Science.gov

Sample records for stratospheric warmings ssws

  1. The Sudden Stratospheric Warming Atlas

    NASA Astrophysics Data System (ADS)

    Sjoberg, J. P.; Butler, A. H.; Seidel, D. J.

    2015-12-01

    Sudden stratospheric warmings (SSWs) are large and rapid temperature increases in the polar stratosphere associated with a complete reversal of the climatological westerly winds in wintertime. These extreme events can have substantial impacts on wintertime surface climate, such as cold air outbreaks over North America and Eurasia, or anomalous warming over Greenland. Here we promote our progress towards a new atlas of historical SSW events and their impacts on the surface. The SSW atlas contains a variety of metrics, time series, maps, and animations for individual SSW events. The atlas will allow users to examine the structure and development of individual SSWs, the variability between events, the surface impacts in temperature and precipitation, and the impacts of SSWs during years with certain tropospheric signatures, like El Niño or La Niña winters.

  2. Defining Sudden Stratospheric Warmings

    NASA Astrophysics Data System (ADS)

    Butler, Amy; Seidel, Dian; Hardiman, Steven; Butchart, Neal; Birner, Thomas; Match, Aaron

    2015-04-01

    The general form of the definition for Sudden Stratospheric Warmings (SSWs) is largely agreed to be a reversal of the temperature gradient and of the zonal circulation polewards of 60° latitude at the 10 hPa level, as developed by the World Meteorological Organization (WMO) in the 1960s and 1970s. However, the details of the definition and its calculation are ambiguous, resulting in inconsistent classifications of SSW events. These discrepancies are problematic for understanding the observed frequency and statistical relationships with SSWs, and for maintaining a robust metric with which to assess wintertime stratospheric variability in observations and climate models. To provide a basis for community-wide discussion, we examine how the SSW definition has changed over time and how sensitive the detection of SSWs is to the definition used. We argue that the general form of the SSW definition should be clarified to ensure that it serves current research and forecasting purposes, and propose possible ways to update the definition.

  3. Evidence for Dynamical Coupling of Stratosphere-MLT during recent minor Stratospheric Warmings in Southern Hemisphere

    NASA Astrophysics Data System (ADS)

    Kim, Yongha; Sunkara, Eswaraiah; Hong, Junseok; Ratnam, Venkat; Chandran, Amal; Rao, Svb; Riggin, Dennis

    2015-04-01

    The mesosphere-lower thermosphere (MLT) response to extremely rare minor sudden stratospheric warming (SSW) events was observed for the first time in the southern hemisphere (SH) during 2010 and is investigated using the meteor radar located at King Sejong Station (62.22°S, 58.78°W), Antarctica. Three episodic SSWs were noticed from early August to late October 2010. The mesospheric wind field was found to significantly differ from normal years due to enhanced planetary wave (PW) activity before the SSWs and secondary PWs in the MLT afterwards. The zonal winds in the mesosphere reversed approximately a week before the SSW occurrence in the stratosphere as has been observed 2002 major SSW, suggesting the downward propagation of disturbance during minor SSWs as well. Signatures of mesospheric cooling (MC) in association with SSWs are found in the Microwave Limb Sounder (MLS) measurements. SD-WACCM simulations are able to produce these observed features.

  4. A New Look at Stratospheric Sudden Warmings. Part II: Evaluation of Numerical Model Simulations

    NASA Technical Reports Server (NTRS)

    Charlton, Andrew J.; Polvani, Lorenza M.; Perlwitz, Judith; Sassi, Fabrizio; Manzini, Elisa; Shibata, Kiyotaka; Pawson, Steven; Nielsen, J. Eric; Rind, David

    2007-01-01

    The simulation of major midwinter stratospheric sudden warmings (SSWs) in six stratosphere-resolving general circulation models (GCMs) is examined. The GCMs are compared to a new climatology of SSWs, based on the dynamical characteristics of the events. First, the number, type, and temporal distribution of SSW events are evaluated. Most of the models show a lower frequency of SSW events than the climatology, which has a mean frequency of 6.0 SSWs per decade. Statistical tests show that three of the six models produce significantly fewer SSWs than the climatology, between 1.0 and 2.6 SSWs per decade. Second, four process-based diagnostics are calculated for all of the SSW events in each model. It is found that SSWs in the GCMs compare favorably with dynamical benchmarks for SSW established in the first part of the study. These results indicate that GCMs are capable of quite accurately simulating the dynamics required to produce SSWs, but with lower frequency than the climatology. Further dynamical diagnostics hint that, in at least one case, this is due to a lack of meridional heat flux in the lower stratosphere. Even though the SSWs simulated by most GCMs are dynamically realistic when compared to the NCEP-NCAR reanalysis, the reasons for the relative paucity of SSWs in GCMs remains an important and open question.

  5. The western Pacific pattern bridging stratospheric sudden warming and ENSO

    NASA Astrophysics Data System (ADS)

    Dai, Ying; Tan, Benkui

    2016-04-01

    Previous studies show that the stratospheric sudden warmings (SSWs) are closely linked to the low height anomalies (LHAs) over the North Pacific and the presence of the LHAs is independent of the phases of the El Nino-Southern Oscillation (ENSO). Based on the wintertime daily reanalysis data from 1958 to 2013, this study demonstrates that most of the LHAs which are linked to SSWs are the footprints left by the western Pacific patterns (WPs), few of them by the Pacific-North American patterns (PNAs), or by mixed WP-PNA patterns. This study also demonstrates that the WPs' LHAs, and therefore the SSWs, are strongly modulated by ENSO and the modulation effects changed over 1958-2013: before 1980, the WPs' LHAs have stronger intensity and longer duration in El Nino winters (EN) than La Nina winters (LN) and ENSO neutral winters (ENSON), and the SSWs occur twice as often during EN, compared to LN and ENSON. After 1980, the WPs' LHAs have stronger intensity in EN and larger frequency during LN than ENSON. Consistently, the SSWs occur nearly twice as often during both EN and LN for this period, compared to ENSON.

  6. Circulation Changes in the Mesosphere and the Lower Thermosphere Associated with Sudden Stratospheric Warmings

    NASA Astrophysics Data System (ADS)

    Hirooka, Toshihiko; Iwao, Koki

    2016-07-01

    Influences of sudden stratospheric warmings (SSWs) reach the mesosphere and the thermosphere. Recently, significant global cooling during SSWs in the thermosphere have been reported on the basis of numerical simulations. However, observational studies are insufficient for the region, so that detailed 3-dimendional structure and the dynamical mechanism are still unclear. Hence, we investigate circulation changes in the mesosphere and thermosphere along with in the stratosphere during SSWs by using TIMED/SABER satellite data and radar data. The SABER observes the atmospheric temperature field in high altitudes up to the lower thermosphere (~120km). Time series of the SABER data includes tidal components, because the satellite orbit is not sun-synchronous and the local time of observation gradually decreases at a specific latitude. The perfect separation of the time series data into tidal and daily changes is difficult especially when diurnal components are amplified. Therefore, we additionally analyze the radar data at some selected stations. Resultantly, north polar temperatures during SSWs show lower thermosphere warming and mesospheric cooling along with the anti-correlated temperature changes in the wide region except over the north pole. In the presentation, we discuss further detailed features of circulation changes associated with SSWs.

  7. Composite analysis of a major sudden stratospheric warming

    NASA Astrophysics Data System (ADS)

    Hocke, K.; Lainer, M.; Schanz, A.

    2015-06-01

    We present the characteristics of a major sudden stratospheric warming (SSW) by using the composite analysis method and ERA Interim reanalysis data from 1979 to 2014. The anomalies of the parameters total ozone column density (TOC), temperature (T), potential vorticity (PV), eastward wind (u), northward wind (v), vertical wind (w), and geopotential height (z) are derived with respect to the ERA Interim climatology (mean seasonal behaviour 1979 to 2014). The composites are calculated by using the time series of the anomalies and the central dates of 20 major SSWs. Increases of up to 90 Dobson units are found for polar TOC after the SSW. Polar TOC remains enhanced until the summer after the major SSW. Precursors of the SSW are a negative TOC anomaly 3 months before the SSW and enhanced temperature at 10 hPa at mid-latitudes about 1 month before the SSW. Eastward wind at 1 hPa is decreased at mid-latitudes about 1 month before the SSW. The 1 hPa geopotential height level is increased by about 500 m during the month before the SSW. These features are significant at the 2σ level for the mean behaviour of the ensemble of the major SSWs. However, knowledge of these precursors may not lead to a reliable prediction of an individual SSW since the variability of the individual SSWs and the polar winter stratosphere is large.

  8. Satellite observations of gravity wave activity and dissipation during sudden stratospheric warmings

    NASA Astrophysics Data System (ADS)

    Ern, Manfred; Preusse, Peter; Riese, Martin

    2015-04-01

    Sudden stratospheric warmings (SSWs) are a circulation anomaly that occurs mainly at high northern latitudes in boreal winter. During major SSWs the eastward directed polar jet reverses, and, for a certain period, the stratosphere is governed by anomalous westward winds. It is known that both planetary waves and gravity waves contribute to the formation and evolution of SSWs. However, the small horizontal scales of gravity waves (tens to a few thousand km) challenge both observations and modeling of gravity waves. Therefore, the role of gravity waves during SSWs is still not fully understood. In particular, gravity waves should play an important role during the recovery of the stratopause and of the eastward directed polar jet after major SSWs. This is indicated by several modeling efforts. However, validation by global observations of gravity waves is still an open issue. Gravity wave momentum fluxes and potential gravity wave drag were derived from HIRDLS and SABER satellite observations, and the role of gravity waves during recent SSWs in the boreal winters 2001/2002-2013/2014 is investigated. We find that gravity waves with slow horizontal phase speeds, likely mountain waves, play an important role during SSWs. Both gravity wave momentum fluxes and gravity wave drag are enhanced before the central date of major SSWs. After the central date, gravity wave momentum fluxes and gravity wave drag in the stratosphere are strongly reduced. Still, gravity wave drag contributes to the wind reversals related to the anomalous westward winds. Another finding is that, after major SSWs, the contribution of gravity wave drag at the bottom of re-established eastward directed polar jets is small. At the top of those jets, however, strong gravity wave drag is found, which indicates that gravity waves contribute to the downward propagation of newly formed polar jets and of elevated stratopauses to their "climatological" altitude. This confirms recent modeling work by, for example

  9. The surface impact of stratospheric sudden warmings in a 1000 year control simulation: sensitivity to event definition and type

    NASA Astrophysics Data System (ADS)

    Maycock, Amanda

    2014-05-01

    Major sudden stratospheric warmings (SSWs) are characterised by large departures of the northern hemisphere winter-time circulation from climatology. Numerous studies have shown that on average these events impact on tropospheric weather patterns leading to a more negative North Atlantic Oscillation index; however, recent studies have suggested that the nature of this downward coupling may be sensitive to the type of SSW (vortex split or displacement). This study explores this issue using a 1000 year pre-industrial control simulation from the IPSL-CM5A-LR model taken from the CMIP5 archive. We identify SSW events using two distinct methods: the widely applied algorithm of Charlton and Polvani (2007) and a 2-D moments-based approach described by Seviour et al (2013). The long simulation offers a unique opportunity to analyse a very large sample of SSW events (~500). We evaluate the relative timing and frequency of SSWs identified by the two methods and examine their impact on the tropospheric state. In contrast to other recent studies, we do not find a significant difference between the impact of split and displacement SSWs on the troposphere in this model. We analyse the evolution of the SSWs that are not consistently identified by the two algorithms, and examine whether they have a significant role in determining the overall impact of SSWs on the troposphere. The large number of warming events enables a comprehensive assessment of the noise that may be associated with analysing stratosphere-troposphere coupling in smaller sample sizes.

  10. Stratospheric predictability and sudden stratospheric warming events

    NASA Astrophysics Data System (ADS)

    Stan, Cristiana; Straus, David M.

    2009-06-01

    A comparative study of the limit of predictability in the stratosphere and troposphere in a coupled general circulation model is carried out using the National Center for Environmental Prediction (NCEP) Climate Forecast System Interactive Ensemble (CFSIE). In "identical twin experiments", we compare the forecast errors of zonal wind and potential temperature in the troposphere and stratosphere for various wave groups. The results show smaller intrinsic error growth in the lower stratosphere compared with troposphere. The limit of predictability of sudden stratospheric warming events, measured by the errors in the divergence of the Eliassen-Palm flux, is dominated by the amplification of small errors in the individual fields due to differences between the phase of the waves.

  11. Ionospheric reaction on sudden stratospheric warming events in Russiás Asia region

    NASA Astrophysics Data System (ADS)

    Polyakova, Anna; Perevalova, Natalya; Chernigovskaya, Marina

    2015-12-01

    The response of the ionosphere to sudden stratospheric warmings (SSWs) in the Asian region of Russia is studied. Two SSW events observed in 2008-2009 and 2012-2013 winter periods of extreme solar minimum and moderate solar maximum are considered. To detect the ionospheric effects caused by SSWs, we carried out a joint analysis of global ionospheric maps (GIM) of the total electron content (TEC), MLS (Microwave Limb Sounder, EOS Aura) measurements of temperature vertical profiles, as well as NCEP/NCAR and UKMO Reanalysis data. For the first time, it was found that during strong SSWs, in the mid-latitude ionosphere the amplitude of diurnal TEC variation decreases nearly half compared to quiet days. At the same time, the intensity of TEC deviations from the background level increases. It was also found that at SSW peak the midday TEC maximum decreases, and night/morning TEC values increase compared to quiet days. It was shown that during SSWs, TEC dynamics was identical for different geophysical conditions.The response of the ionosphere to sudden stratospheric warmings (SSWs) in the Asian region of Russia is studied. Two SSW events observed in 2008-2009 and 2012-2013 winter periods of extreme solar minimum and moderate solar maximum are considered. To detect the ionospheric effects caused by SSWs, we carried out a joint analysis of global ionospheric maps (GIM) of the total electron content (TEC), MLS (Microwave Limb Sounder, EOS Aura) measurements of temperature vertical profiles, as well as NCEP/NCAR and UKMO Reanalysis data. For the first time, it was found that during strong SSWs, in the mid-latitude ionosphere the amplitude of diurnal TEC variation decreases nearly half compared to quiet days. At the same time, the intensity of TEC deviations from the background level increases. It was also found that at SSW peak the midday TEC maximum decreases, and night/morning TEC values increase compared to quiet days. It was shown that during SSWs, TEC dynamics was

  12. Sudden stratospheric warmings and tropospheric blockings in a multi-century simulation of the IPSL-CM5A coupled climate model

    NASA Astrophysics Data System (ADS)

    Vial, Jessica; Osborn, Tim J.; Lott, François

    2013-05-01

    The relation between sudden stratospheric warmings (SSWs) and blocking events is analyzed in a multi-centennial pre-industrial simulation of the Institut Pierre Simon Laplace coupled model (IPSL-CM5A), prepared for the fifth phase of the coupled model intercomparison project. The IPSL model captures a fairly realistic distribution of both SSWs and tropospheric blocking events, albeit with a tendency to overestimate the frequency of blocking in the western Pacific and underestimate it in the Euro-Atlantic sector. The 1000-year long simulation reveals statistically significant differences in blocking frequency and duration over the 40-day periods preceding and following the onset of SSWs. More specifically, there is an enhanced blocking frequency over Eurasia before SSWs, followed by an westward displacement of blocking anomalies over the Atlantic region as SSWs evolve and then decline. The frequency of blocking is reduced over the western Pacific sector during the life-cycle of SSWs, while the model simulates no significant relationship with eastern Pacific blocks. Finally, these changes in blocking frequency tend to be associated with a shift in the distribution of blocking lifetime toward longer-lasting blocking events before the onset of SSWs and shorter-lived blocks after the warmings. This study systematically verifies that the results are consistent with the two pictures that (1) blockings produce planetary scale anomalies that can force vertically propagating Rossby waves and then SSWs when the waves break and (2) SSWs affect blockings in return, for instance via the effect they have on the North Atlantic Oscillation.

  13. Temperature Deviations in the Midlatitude Mesosphere During Stratospheric Warmings as Measured with Rayleigh-Scatter Lidar

    NASA Astrophysics Data System (ADS)

    Sox, Leda; Wickwar, Vincent; Fish, Chad; Herron, Joshua P.

    2016-06-01

    While mesospheric temperature anomalies associated with Sudden Stratospheric Warmings (SSWs) have been observed extensively in the polar regions, observations of these anomalies at midlatitudes are sparse. The original Rayleigh-scatter lidar that operated at the Atmospheric Lidar Observatory (ALO; 41.7°N, 111.8°W) in the Center for Atmospheric and Space Sciences (CASS) on the campus of Utah State University (USU) collected an extensive set of temperature data for 11 years in the 45-90 km altitude range. This work focuses on the extensive Rayleigh lidar observations made during six major SSW events that occurred between 1993 and 2004, providing a climatological study of the midlatitude mesospheric temperatures during these SSW events. An overall disturbance pattern was observed in the mesospheric temperatures during these SSWs. It included coolings in the upper mesosphere, comparable to those seen in the polar regions during SSW events, and warmings in the lower mesosphere.

  14. Analysis of data from spacecraft (stratospheric warmings)

    NASA Technical Reports Server (NTRS)

    1974-01-01

    The details of the stratospheric warming processes as to time, area, and intensity were established, and the warmings with other terrestrial and solar phenomena occurring at satellite platform altitudes, or observable from satellite platforms, were correlated. Links were sought between the perturbed upper atmosphere (mesosphere and thermosphere) and the stratosphere that might explain stratospheric warmings.

  15. TEC disturbances during major Sudden Stratospheric Warmings in the mid-latitude ionosphere.

    NASA Astrophysics Data System (ADS)

    Polyakova, Anna; Voeykov, Sergey; Chernigovskaya, Marina; Perevalova, Natalia

    Using total electron content (TEC) global ionospheric maps, dual-frequency GPS receivers TEC data and MLS (Microwave Limb Sounder, EOS Aura) atmospheric temperature data the ionospheric disturbances during the strong sudden stratospheric warmings (SSWs) of 2008/2009 and 2012/2013 winters are investigated in Russia's Asia region. It is established that during the SSW maximum the midday TEC decrease and the night/morning TEC increase compared to quiet days are observed in the mid-latitude ionosphere. As a result it caused the decrease of the diurnal TEC variations amplitude of about two times in comparison with the undisturbed level. The analysis of TEC deviations from the background level during the SSWs has shown that deviations dynamics vary depending on the observation point position. Negative deviations of TEC are registered in the ionosphere above the region of maximum stratosphere heating (the region of the stratospheric circulation change) as well as above the anticyclone. On the contrary, TEC values increase compared to the quiet day's values above the stratosphere cyclone. It is shown that during maximum phase of a warming, and within several days after it the amplification of wave TEC variations intensity with periods of up to 60 min is registered in ionosphere. The indicated effects may be attributed to the vertical transfer of molecular gas from a stratospheric heating region to the thermosphere as well as to the increase in activity of planetary and gravity waves which is usually observed during strong SSWs. The study is supported by the RF President Grant of Public Support for RF Leading Scientific Schools (NSh-2942.2014.5), the RF President Grant No. MK-3771.2012.5 and RFBR Grant No. 12-05-00865_а.

  16. Absorbing and reflecting sudden stratospheric warming events and their relationship with tropospheric circulation

    NASA Astrophysics Data System (ADS)

    Kodera, Kunihiko; Mukougawa, Hitoshi; Maury, Pauline; Ueda, Manabu; Claud, Chantal

    2016-01-01

    Sudden stratospheric warming (SSW) events have received increased attention since their impacts on the troposphere became evident recently. Studies of SSW usually focus on polar stratospheric conditions; however, understanding the global impact of these events requires studying them from a wider perspective. Case studies are used to clarify the characteristics of the stratosphere-troposphere dynamical coupling, and the meridional extent of the phenomena associated with SSW. Results show that differences in the recovery phase can be used to classify SSW events into two types. The first is the absorbing type of SSW, which has a longer timescale as well as a larger meridional extent due to the persistent incoming planetary waves from the troposphere. The absorbing type of SSW is related to the annular mode on the surface through poleward and downward migration of the deceleration region of the polar night jet. The other is the reflecting type. This is characterized by a quick termination of the warming episode due to the reflection of planetary waves in the stratosphere, which leads to an amplification of tropospheric planetary waves inducing strong westerlies over the North Atlantic and blocking over the North Pacific sector. Differences in the tropospheric impact of the absorbing and reflecting SSWs are also confirmed with composite analysis of 22 major SSWs.

  17. Stratospheric sudden warming and lunar tide

    NASA Astrophysics Data System (ADS)

    Yamazaki, Yosuke; Kosch, Michael

    2016-07-01

    A stratospheric sudden warming is a large-scale disturbance in the middle atmosphere. Recent studies have shown that the effect of stratospheric sudden warnings extends well into the upper atmosphere. A stratospheric sudden warming is often accompanied by an amplification of lunar tides in the ionosphere/theremosphere. However, there are occasionally winters when a stratospheric sudden warming occurs without an enhancement of the lunar tide in the upper atmosphere, and other winters when large lunar tides are observed without a strong stratospheric sudden warming. We examine the winters when the correlation breaks down and discuss possible causes.

  18. Gravity waves in the thermosphere during a sudden stratospheric warming

    NASA Astrophysics Data System (ADS)

    Yigit, E.; Medvedev, A. S.

    2012-12-01

    For the first time, the propagation and dissipation of internal gravity waves (GWs) of lower atmospheric origin to the thermosphere above the turbopause (~105 km) during a sudden stratospheric warming (SSW) are examined. The study is performed with a general circulation model (GCM) coupling the lower atmosphere with the thermosphere and the implemented spectral nonlinear extended GW parameterization of Yigit et al. (2008). The Yigit et al. (2008) extended GW parameterization calculates the propagation and dissipation of small-scale GWs in the whole atmosphere system by physically taking into account ion drag, molecular viscosity and thermal conduction, eddy viscosity, nonlinear diffusion, and radiative damping in form of Newtonian cooling. Model simulations reveal a strong modulation by SSWs of GW activity, momentum deposition rates, and the circulation feedbacks at heights up to F region altitudes (~270 km). Wave-induced root mean square wind fluctuations increase several times during the warming in the thermosphere above the turbopause. This occurs mainly due to a reduction of filtering eastward traveling GWs by the weaker stratospheric jet. These waves propagate higher under the favorable conditions, grow in amplitude, and produce stronger forcing on the mean flow, compared to pre-warming period, when they are dissipated in the thermosphere. The evolution of stratospheric and mesospheric winds during an SSW life-cycle creates a robust and distinctive response in GW activity and mean fields deeply in the thermosphere. Yigit, E., A.~D. Aylward, and A.~S. Medvedev (2008), Parameterization of the effects of vertically propagating gravity waves for thermosphere general circulation models: Sensitivity study, J. Geophys. Res., 113, D19106, doi:10.1029/2008JD010135.

  19. Tropospheric predictability around stratospheric warming events examined with an idealized forecast ensemble

    NASA Astrophysics Data System (ADS)

    Hörnqvist, E.; Körnich, H.

    2012-04-01

    By representing sudden stratospheric warming events (SSWs) in numerical weather prediction models, the predictability length could possibly be improved. It has been suggested that this improvement depends on the initial day of the forecast relative to the central date of the SSW. In this project this hypothesis is tested in the framework of an idealized general circulation model. Furthermore, it will be examined how uncertainties of the initial conditions and model errors in the forecast model affect the predictability around stratospheric warming events. Identical-twin forecast experiments are performed with the Kühlungsborn Mechanistic general Circulation Model KMCM that extends to the stratopause. In a 20-year truth run with perpetual January conditions, 21 SSWs are identified. Ensemble forecasts using random field perturbations in the initial conditions are conducted with initial dates from 20 days before to 20 days after each SSW central date. In four different experiments, we examine how the tropospheric predictability depends on perturbations in troposphere, stratosphere or both, and on model errors in the stratospheric radiative equilibrium temperature. The results show that a forecast initialised before the SSW central date has a greater forecast skill than after. On average useful forecast for the zonal mean zonal wind at 60N and 850 hPa are extended by 10 days, when initialized up to 12 days before the SSW. This extension is robust for the different perturbation experiments and also when a model error was introduced. Thus, the experiments confirm that the largest improvement of predictability is achieved, when the forecast is initialised before the sudden stratospheric warming event.

  20. Satellite observations of middle atmosphere gravity wave absolute momentum flux and of its vertical gradient during recent stratospheric warmings

    NASA Astrophysics Data System (ADS)

    Ern, Manfred; Trinh, Quang Thai; Kaufmann, Martin; Krisch, Isabell; Preusse, Peter; Ungermann, Jörn; Zhu, Yajun; Gille, John C.; Mlynczak, Martin G.; Russell, James M., III; Schwartz, Michael J.; Riese, Martin

    2016-08-01

    Sudden stratospheric warmings (SSWs) are circulation anomalies in the polar region during winter. They mostly occur in the Northern Hemisphere and affect also surface weather and climate. Both planetary waves and gravity waves contribute to the onset and evolution of SSWs. While the role of planetary waves for SSW evolution has been recognized, the effect of gravity waves is still not fully understood, and has not been comprehensively analyzed based on global observations. In particular, information on the gravity wave driving of the background winds during SSWs is still missing.We investigate the boreal winters from 2001/2002 until 2013/2014. Absolute gravity wave momentum fluxes and gravity wave dissipation (potential drag) are estimated from temperature observations of the satellite instruments HIRDLS and SABER. In agreement with previous work, we find that sometimes gravity wave activity is enhanced before or around the central date of major SSWs, particularly during vortex-split events. Often, SSWs are associated with polar-night jet oscillation (PJO) events. For these events, we find that gravity wave activity is strongly suppressed when the wind has reversed from eastward to westward (usually after the central date of a major SSW). In addition, gravity wave potential drag at the bottom of the newly forming eastward-directed jet is remarkably weak, while considerable potential drag at the top of the jet likely contributes to the downward propagation of both the jet and the new elevated stratopause. During PJO events, we also find some indication for poleward propagation of gravity waves. Another striking finding is that obviously localized gravity wave sources, likely mountain waves and jet-generated gravity waves, play an important role during the evolution of SSWs and potentially contribute to the triggering of SSWs by preconditioning the shape of the polar vortex. The distribution of these hot spots is highly variable and strongly depends on the zonal and

  1. Sudden stratospheric warmings as catastrophes

    NASA Technical Reports Server (NTRS)

    Chao, W. C.

    1985-01-01

    The sudden stratospheric warming (SSW) process is qualitatively studied using a conceptual and numerical approach guided by catastrophe theory. A simple example of a catastrophe taken from nonlinear dynamics is given, and results from previous modelling studies of SSW are interpreted in light of catastrophe theory. Properties of this theory such as hysteresis, cusp, and triggering essential to SSW are numerically demonstrated using the truncated quasi-geostrophic beta-plane model of Holton and Mass (1976). A qualitative explanation of the transition from the steady regime to the vacillation regime is given for the Holton and Mass model in terms of the topographically induced barotropic Rossby wave instability. Some implications for the simulation and prediction of SSW are discussed.

  2. Gravity wave activity during stratospheric sudden warmings in the 2007-2008 Northern Hemisphere winter

    NASA Astrophysics Data System (ADS)

    Wang, Ling; Alexander, M. Joan

    2009-09-01

    We use temperature retrievals from the Constellation Observing System for Meteorology, Ionosphere and Climate (COSMIC)/Formosa Satellite Mission 3 (FORMOSAT-3) and Challenging Minisatellite Payload (CHAMP) Global Positioning Satellite (GPS) radio occultation profiles and independent temperature retrievals from the EOS satellite High Resolution Dynamics Limb Sounder (HIRDLS) and Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) aboard the TIMED satellite to investigate stratospheric sudden warming (SSW) events and the accompanying gravity wave (GW) temperature amplitudes in the 2007-2008 Northern Hemisphere winter. We identify four SSW events (including a major one) occurring from late January to late February in 2008. We detect enhanced GW amplitudes in the stratosphere and subdued GW amplitudes in the lower mesosphere during the warming events. The timing of GW enhancement/suppression and warming/cooling events was generally close (within a couple days). We also find that stratospheric GW amplitudes were generally larger at the polar vortex edge and smaller in the vortex core and outside of the vortex and that stratospheric GW amplitudes were generally small over the North Pacific. Using a simplified GW dispersion relation and a GW ray-tracing experiment, we demonstrate that the enhanced GW amplitudes in the stratosphere during SSWs could be explained largely by GW propagation considerations. The existence of GW critical levels (the level at which the background wind is the same as the GW phase speed) near the stratopause during SSWs would block propagation of GWs into the mesosphere and thus could lead to the observed subdued GW activity in the lower mesosphere. Since this is the first study to analyze the COSMIC and CHAMP GPS temperature retrievals up to 60 km in altitude, we compare the GPS analysis with those from HIRDLS and SABER measurements. We find that the temporal variability of zonal mean temperatures derived from the GPS data is

  3. Sudden Stratospheric Warming of 2012-2013, its predictability, and its impact on the Northern Hemispheric winter

    NASA Astrophysics Data System (ADS)

    Tripathi, O. P.; Charlton-Perez, A. J.; Baldwin, M. P.; Charron, M.; Sigmond, M.; Eckermann, S. D.; Gerber, E. P.; Kuroda, Y.; Mizuta, R.; Jackson, D.; Lang, A.; Roff, G.; Son, S.; Kim, B.

    2013-12-01

    The stratospheric winter is characterized by strong circumpolar westerly winds and the region of colder polar cap temperatures called the polar vortex. During every other winter or so this polar winter circulation undergoes a Stratospheric Sudden Warming (SSW), a rapid deceleration resulting in easterly winds on the time scale of a few days a large increase in polar cap temperature. The predictability of these extreme stratospheric events are crucial for their impact on the tropospheric forecast on a timescale of one to two weeks. The Stratospheric Network on Assessment of Predictability (SNAP), a network of major operational forecasting centers, aims to understand the stratosphere-troposphere link and quantify how far in advance SSWs can be predicted and add skill to tropospheric forecasts. During the 2012-2013 winter, anomalous upward propagating planetary wave activity was observed during the second and third weak of December. Around 22nd of December there was a large eddy heat flux anomaly at 10 hPa. This was followed by a rapid deceleration of westerly circulation in the stratosphere starting around January 2, and within 3-4 days the circulation reversed on January 7, 2013. Within a couple of days the polar vortex split in two with a large increase in polar cap temperature. This stratospheric dynamical activity was followed by an equatorward shift of the tropospheric jet stream and a high pressure anomaly over North Atlantic, resulting in severe cold conditions in the UK and Northern Europe. Our current skill in predicting SSWs and therefore its consequential impact on tropospheric weather forecast is very limited due to the gap in proper understanding of stratosphere-troposphere coupling. SNAP has organized predictability experiments in different phases conducted by the operational centers. In this presentation we will show first results from SNAP for the Sudden Stratospheric Warming of January 2013. We will show how far in advance different models were able

  4. Observations of planetary waves in the mesosphere-lower thermosphere during stratospheric warming events

    NASA Astrophysics Data System (ADS)

    Stray, N. H.; Orsolini, Y. J.; Espy, P. J.; Limpasuvan, V.; Hibbins, R. E.

    2015-05-01

    This study investigates the effect of stratospheric sudden warmings (SSWs) on planetary wave (PW) activity in the mesosphere-lower thermosphere (MLT). PW activity near 95 km is derived from meteor wind data using a chain of eight SuperDARN radars at high northern latitudes that span longitudes from 150° W to 25° E and latitudes from 51 to 66° N. Zonal wave number 1 and 2 components were extracted from the meridional wind for the years 2000-2008. The observed wintertime PW activity shows common features associated with the stratospheric wind reversals and the accompanying stratospheric warming events. Onset dates for seven SSW events accompanied by an elevated stratopause (ES) were identified during this time period using the Specified Dynamics Whole Atmosphere Community Climate Model (SD-WACCM). For the seven events, a significant enhancement in wave number 1 and 2 PW amplitudes near 95 km was found to occur after the wind reversed at 50 km, with amplitudes maximizing approximately 5 days after the onset of the wind reversal. This PW enhancement in the MLT after the event was confirmed using SD-WACCM. When all cases of polar cap wind reversals at 50 km were considered, a significant, albeit moderate, correlation of 0.4 was found between PW amplitudes near 95 km and westward polar-cap stratospheric winds at 50 km, with the maximum correlation occurring ∼ 3 days after the maximum westward wind. These results indicate that the enhancement of PW amplitudes near 95 km is a common feature of SSWs irrespective of the strength of the wind reversal.

  5. Investigating troposhpere-stratosphere coupling during the southern hemisphere sudden stratospheric warming using an adjoint model.

    NASA Astrophysics Data System (ADS)

    Holdaway, D.; Coy, L.

    2015-12-01

    In September 2002 a major sudden stratospheric warming (SSW) occurred in the southern hemisphere. Although numerous SSWs have been observed in the northern hemisphere, this remains the only recorded major SSW in the southern hemisphere. Much debate has focused on this unique event and the causes, even resulting in a special issue of the Journal of Atmospheric Science. In this work we use the adjoint of NASA's Goddard Earth Observing System version 5 (GEOS-5) to investigate sensitivity to initial conditions during the onset of the 2002 SSW. The adjoint model provides a framework for propagating gradients with respect to the model state backwards in time. As such it is used to reveal aspects of the model initial conditions that have the biggest impact on the temperature in the stratosphere during the warming. The adjoint model reveals a large sensitivity over the southern Atlantic ocean and in the troposphere. This reinforces previous studies that attributed the SSW to a blocking ridge in this region. By converting sensitivity to perturbations it is shown that relatively small localized tropospheric perturbations to winds and temperature can be transported to the stratosphere and have a large impact on the SSW.

  6. Mixing processes following the final stratospheric warming

    NASA Technical Reports Server (NTRS)

    Hess, Peter G.

    1991-01-01

    An investigation is made of the dynamics responsible for the mixing and dissolution of the polar vortex during the final stratospheric warmings. The dynamics and transport during a Northern Hemisphere final stratospheric warming are simulated via a GCM and an associated offline N2O transport model. The results are compared with those obtained from LIMS data for the final warming of 1979, with emphasis on the potential vorticity evolution in the two datasets, the modeled N2O evolution, and the observed O3 evolution. Following each warming, the remnants of the originally intact vortex are found to gradually homogenize with the atmosphere at large. Two processes leading to this homogenization are identified following the final warmings, namely, the potential vorticity field becomes decorrelated from that of the chemical tracer, and the vortex remnants begin to tilt dramatically in a vertical direction.

  7. Analysis of data from spacecraft (stratospheric warmings)

    NASA Technical Reports Server (NTRS)

    1973-01-01

    Investigations involved a search through existing literature and data to obtain case histories for the six or more stratospheric warmings that occurred in April - May 1969, June - July 1969, August 1969, December 1969 - January 1970, December 1970 - January 1971, and January 1973 - February 1973. For each of these warmings the following steps have been taken in preparation for analysis: (1) defining the nature of the problem; (2) literature search of stratwarmings and solar-terrestrial phenomens; and (3) file of data sources, especially stratospheric temperatures (radiances) and geophysical indices.

  8. Simulated sudden stratospheric warming - Synoptic evolution

    NASA Technical Reports Server (NTRS)

    Blackshear, W. T.; Grose, W. L.; Turner, R. E.

    1987-01-01

    An analysis is presented of a sudden stratospheric warming event which occurred spontaneously during a general circulation model simulation of the global atmospheric circulation. Two separate warming pulses exhibit the same dynamical evolution with a 'cycle' of about two weeks. Two distinct phases of the warming cycle are apparent: (1) the generation of an intense localized warm cell in conjunction with significant adiabatic heating associated with cross-isobar flow which has been induced by vertically propagating long wave disturbances; and (2) the northward transport of that warm cell via advection by the essentially geostrophic windfield corresponding to an intense, offset polar cyclone, in conjunction with a strong Aleutian anticyclone. During the first warming pulse in January, a moderate Aleutian anticyclone was in place prior to the warming cycle and was intensified by interaction with an eastward traveling anticyclone induced by the differential advection of the warm cell. The second warming pulse occurred in early February with a strong Aleutian anticyclone already established. In contrast to the January event, the warming in February culminated with reversal of the zonal westerlies to easterlies over a significant depth of the stratosphere.

  9. Coupling in the middle atmosphere related to the 2013 major sudden stratospheric warming

    NASA Astrophysics Data System (ADS)

    de Wit, R. J.; Hibbins, R. E.; Espy, P. J.; Hennum, E. A.

    2015-03-01

    The previously reported observation of anomalous eastward gravity wave forcing at mesopause heights around the onset of the January 2013 major sudden stratospheric warming (SSW) over Trondheim, Norway (63° N, 10° E), is placed in a global perspective using Microwave Limb Sounder (MLS) temperature observations from the Aura satellite. It is shown that this anomalous forcing results in a clear cooling over Trondheim about 10 km below mesopause heights. Conversely, near the mesopause itself, where the gravity wave forcing was measured, observations with meteor radar, OH airglow and MLS show no distinct cooling. Polar cap zonal mean temperatures show a similar vertical profile. Longitudinal variability in the high northern-latitude mesosphere and lower thermosphere (MLT) is characterized by a quasi-stationary wave-1 structure, which reverses phase at altitudes below ~ 0.1 hPa. This wave-1 develops prior to the SSW onset, and starts to propagate westward at the SSW onset. The latitudinal pole-to-pole temperature structure associated with the major SSW shows a warming (cooling) in the winter stratosphere (mesosphere) which extends to about 40° N. In the stratosphere, a cooling extending over the equator and far into the summer hemisphere is observed, whereas in the mesosphere an equatorial warming is noted. In the Southern Hemisphere mesosphere, a warm anomaly overlaying a cold anomaly is present, which is shown to propagate downward in time. This observed structure is in accordance with the temperature perturbations predicted by the proposed interhemispheric coupling mechanism for cases of increased winter stratospheric planetary wave activity, of which major SSWs are an extreme case. These results provide observational evidence for the interhemispheric coupling mechanism, and for the wave-mean flow interaction believed to be responsible for the establishment of the anomalies in the summer hemisphere.

  10. The 2010 Antarctic ozone hole: Observed reduction in ozone destruction by minor sudden stratospheric warmings

    PubMed Central

    de Laat, A. T. J.; van Weele, M.

    2011-01-01

    Satellite observations show that the 2010 Antarctic ozone hole is characterized by anomalously small amounts of photochemical ozone destruction (40-60% less than the 2005-2009 average). Observations from the MLS instrument show that this is mainly related to reduced photochemical ozone destruction between 20-25 km altitude. Lower down between 15-20 km the atmospheric chemical composition and photochemical ozone destruction is unaffected. The modified chemical composition and chemistry between 20-25 km altitude in 2010 is related to the occurrence of a mid-winter minor Antarctic Sudden Stratospheric Warming (SSW). The measurements indicate that the changes in chemical composition are related to downward motion of air masses rather than horizontal mixing, and affect stratospheric chemistry for several months. Since 1979, years with similar anomalously small amounts of ozone destruction are all characterized by either minor or major SSWs, illustrating that their presence has been a necessary pre-condition for reduced Antarctic stratospheric ozone destruction. PMID:22355557

  11. The 2010 Antarctic ozone hole: observed reduction in ozone destruction by minor sudden stratospheric warmings.

    PubMed

    de Laat, A T J; van Weele, M

    2011-01-01

    Satellite observations show that the 2010 Antarctic ozone hole is characterized by anomalously small amounts of photochemical ozone destruction (40-60% less than the 2005-2009 average). Observations from the MLS instrument show that this is mainly related to reduced photochemical ozone destruction between 20-25 km altitude. Lower down between 15-20 km the atmospheric chemical composition and photochemical ozone destruction is unaffected. The modified chemical composition and chemistry between 20-25 km altitude in 2010 is related to the occurrence of a mid-winter minor Antarctic Sudden Stratospheric Warming (SSW). The measurements indicate that the changes in chemical composition are related to downward motion of air masses rather than horizontal mixing, and affect stratospheric chemistry for several months. Since 1979, years with similar anomalously small amounts of ozone destruction are all characterized by either minor or major SSWs, illustrating that their presence has been a necessary pre-condition for reduced Antarctic stratospheric ozone destruction. PMID:22355557

  12. Connection between the midlatitude mesosphere and sudden stratospheric warmings as measured by Rayleigh-scatter lidar

    NASA Astrophysics Data System (ADS)

    Sox, Leda; Wickwar, Vincent B.; Fish, Chad S.; Herron, Joshua P.

    2016-05-01

    While the mesospheric temperature anomalies associated with Sudden Stratospheric Warmings (SSWs) have been observed extensively in the polar regions, observations of these anomalies at midlatitudes are much more sparse. The Rayleigh-scatter lidar system, which operated at the Center for Atmospheric and Space Sciences on the campus of Utah State University (41.7°N, 111.8°W), collected a very dense set of observations, from 1993 to 2004, over a 45-90 km altitude range. This paper focuses on Rayleigh lidar temperatures derived during the six major SSW events that occurred during the 11 year period when the lidar was operating and aims to characterize the local response to these midlatitude SSW events. In order to determine the characteristics of these mesospheric temperature anomalies, comparisons were made between the temperatures from individual nights during a SSW event and a climatological temperature profile. An overall disturbance pattern was observed in the mesospheric temperatures associated with SSW events, including coolings in the upper mesosphere and warmings in the upper stratosphere and lower mesosphere, both comparable to those seen at polar latitudes.

  13. Observations of Enhanced Semi Diurnal Lunar Tides in the Mesosphere and Lower Thermosphere at Mid and High Northern Latitudes during Sudden Stratospheric Warming Events

    NASA Astrophysics Data System (ADS)

    Chau, J. L.; Hoffmann, P.; Pedatella, N. M.; Matthias, V.

    2014-12-01

    In recent years, there have been a series of reported ground- and satellite-based observations of lunar tide signatures in the equatorial and low latitude ionosphere around sudden stratospheric warming (SSW) events. More recently, Pedatella et al. [2014], using the Whole Atmosphere Community Climate Model Extended version (WACCM-X) and the thermosphere-ionosphere-mesosphere electrodynamics general circulation model (TIME-GCM) has demonstrated that the semi-diurnal lunar tide (M2) is an important contributor to the ionosphere variability during the 2009 SSW. Although the model results were focused on the low-latitude ionosphere and compare with Jicamarca electric fields, Pedatella et al. [2014] also reported that the M2 was enhanced in the northern mid and high latitudes (between 30 and 70oN) at mesospheric and lower thermospheric altitudes during the 2009 SSW. Motivated by this finding, we have analyzed winds from 80 to 100 kms obtained with meteor radars from Juliusruh (54oN) and Andøya (69oN) stations during five SSWs (2008, 2009, 2010, 2012, and 2013). By fitting the usual solar components (diurnal and semidiurnal and M2, we have been able to identify clearly the enhancement of the M2 as well as the semi diurnal solar tide during all these SSWs. The qualitative agreement with the Pedatella et al. [2014] simulations is very good, i.e., stronger signature at 54oN than at 69oN and enhanced around SSW. The analysis of other SSWs not only show the clear relationship with SSWs, but also the different behaviors in strength, time of occurrence, duration, etc., that appear to be associated to the mean wind dynamics as well as the stratospheric planetary wave characteristics.

  14. Stratospheric warmings during February and March 1993

    NASA Technical Reports Server (NTRS)

    Manney, G. L.; Zurek, R. W.; O'Neill, A.; Swinbank, R.; Kumer, J. B.; Mergenthaler, J. L.; Roche, A. E.

    1994-01-01

    Two stratospheric warmings during February and March 1993 are described using United Kingdom Meteorological Office (UKMO) analyses, calculated potential vorticity (PV) and diabetic heating, and N2O observed by the Cryogenic Limb Array Etalon Spectrometer (CLAES) instrument on the Upper Atmosphere Research Satellite (UARS). The first warming affected temperatures over a larger region, while the second produced a larger region of reversed zonal winds. Tilted baroclinic zones formed in the temperature field, and the polar vortex tilted westward with height. Narrow tongues of high PV and low N2O were drawn off the polar vortex, and irreversibly mixed. Tongues of material were drawn from low latitudes into the region between the polar vortex and the anticyclone; diabatic descent was also strongest in this region. Increased N2O over a broad region near the edge of the polar vortex indicates the importance of horizontal transport. N2O decreased in the vortex, consistent with enhanced diabatic descent during the warmings.

  15. Impact of the semidiurnal lunar tide on the midlatitude thermospheric wind and ionosphere during sudden stratosphere warmings

    NASA Astrophysics Data System (ADS)

    Pedatella, N. M.; Maute, A.

    2015-12-01

    Variability of the midlatitude ionosphere and thermosphere during the 2009 and 2013 sudden stratosphere warmings (SSWs) is investigated in the present study using a combination of Constellation Observing System for Meteorology, Ionosphere, and Climate (COSMIC) observations and thermosphere-ionosphere-mesosphere electrodynamics general circulation model (TIME-GCM) simulations. Both the COSMIC observations and TIME-GCM simulations reveal perturbations in the F region peak height (hmF2) at Southern Hemisphere midlatitudes during SSW time periods. The perturbations are ˜20-30 km, which corresponds to 10-20% variability of the background mean hmF2. The TIME-GCM simulations and COSMIC observations of the hmF2 variability are in overall good agreement, and the simulations can thus be used to understand the physical processes responsible for the hmF2 variability. Through comparison of simulations with and without the migrating semidiurnal lunar tide (M2), we conclude that the midlatitude hmF2 variability is primarily driven by the propagation of the M2 into the thermosphere where it modulates the field-aligned neutral winds, which in turn raise and lower the F region peak height. Though there are subtle differences, the consistency of the behavior between the 2009 and 2013 SSWs suggests that variability in the Southern Hemisphere midlatitude ionosphere and thermosphere is a consistent feature of the SSW impact on the upper atmosphere.

  16. Evidence for stratospheric sudden warming effects on the upper thermosphere derived from satellite orbital decay data during 1967-2013

    NASA Astrophysics Data System (ADS)

    Yamazaki, Yosuke; Kosch, Michael J.; Emmert, John T.

    2015-08-01

    We investigate possible impact of stratospheric sudden warmings (SSWs) on the thermosphere by using long-term data of the global average thermospheric total mass density derived from satellite orbital drag during 1967-2013. Residuals are analyzed between the data and empirical Global Average Mass Density Model (GAMDM) that takes into account density variability due to solar activity, season, geomagnetic activity, and long-term trend. A superposed epoch analysis of 37 SSW events reveals a density reduction of 3-7% at 250-575 km around the time of maximum polar vortex weakening. The relative density perturbation is found to be greater at higher altitudes. The temperature perturbation is estimated to be -7.0 K at 400 km. We show that the density reduction can arise from enhanced wave forcing from the lower atmosphere.

  17. Mesospheric signatures observed during 2010 minor stratospheric warming at King Sejong Station (62°S, 59°W)

    NASA Astrophysics Data System (ADS)

    Eswaraiah, S.; Kim, Yong Ha; Hong, Junseok; Kim, Jeong-Han; Ratnam, M. Venkat; Chandran, A.; Rao, S. V. B.; Riggin, Dennis

    2016-03-01

    A minor stratospheric sudden warming (SSW) event was noticed in the southern hemisphere (SH) during September (day 259) 2010 along with two episodic warmings in early August (day 212) and late October (day 300) 2010. Among the three warming events, the signature of mesosphere response was detected only for the September event in the mesospheric wind dataset from both meteor radar and MF radar located at King Sejong Station (62°S, 59°W) and Rothera (68°S, 68°W), Antarctica, respectively. The zonal winds in the mesosphere reversed approximately a week before the September SSW event, as has been observed in the 2002 major SSW. Signatures of mesospheric cooling (MC) in association with stratospheric warmings are found in temperatures measured by the Microwave Limb Sounder (MLS). Simulations of specified dynamics version of Whole Atmosphere Community Climate Model (SD-WACCM) are able to reproduce these observed features. The mesospheric wind field was found to differ significantly from that of normal years probably due to enhanced planetary wave (PW) activity before the SSW. From the wavelet analysis of wind data of both stations, we find that strong 14-16 day PWs prevailed prior to the SSW and disappeared suddenly after the SSW in the mesosphere. Our study provides evidence that minor SSWs in SH can result in significant effects on the mesospheric dynamics as in the northern hemisphere.

  18. Middle-atmospheric Ozone and HCl anomalies during the polar stratospheric warming 2010 observed by JEM/SMILES

    NASA Astrophysics Data System (ADS)

    Esmaeili Mahani, M.; Kreyling, D.; Sagawa, H.; Murata, I.; Kasaba, Y.; Kasai, Y.

    2012-12-01

    In this study we focused on investigating ozone and HCl variations and anomalies in the middle atmosphere due to the Stratospheric Sudden Warming (SSW) event of Arctic winter 2009-2010 using JEM/SMILES data. HCl anomalies in evolution of a SSW have been studied for the first time. SSWs are dramatic events in the winter stratosphere of the Northern Hemisphere where the deceleration or reversal of the eastward winds is accompanied by an increase of temperature by several tens of degrees. The main cause of this phenomenon is known to be the interaction of zonal mean flow with upward propagating transient planetary waves from the troposphere in mid-winter leading to a vortex displacement or break down. SSWs are dynamical disturbances found to affect both dynamics and chemical compositions of the middle atmosphere still having several different atmospheric features and behaviors to be studied. The Superconducting sub-Millimeter Limb Emission Sounder (SMILES) is a highly sensitive radiometer to observe various atmospheric compositions from upper troposphere to the mesosphere. SMILES was developed by the Japanese Aerospace eXploration Agency (JAXA) and the National Institute of Communications and Technology (NICT) located at the Japanese Experiment Module (JEM) on board the International Space Station (ISS). From October 2009 to April 2010, SMILES has accurately measured the vertical distributions and the diurnal variations of for example ozone and HCl with the accuracy of less than 8% and 5% in the middle atmosphere respectively. By using SMILES data the SSW event of 2010 was confirmed on 25-January categorized as a major, vortex displacement warming. After the SSW, ozone values enhanced up to 15-20% in mid-stratosphere due to the meridional transport from lower latitudes and weakening of the polar vortex. The mesospheric ozone response will also be demonstrated and discussed. For HCl, the total increase of 10% in Upper Stratosphere Lower Mesosphere (USLM) before the

  19. Role of Planetary waves in Winter Stratospheric Warming: Decadal variability

    NASA Astrophysics Data System (ADS)

    Bhagavathiammal, G. J.

    2016-07-01

    Winter Stratospheric dynamics is quiet variable and fascinating in nature, because of the energetic planetary waves, propagates upward from troposphere. Using ECMWF ERA Interim Reanalysis datasets, this paper presents the decadal behaviour of winter stratosphere. Traditional diagnostic tool, Eliassen Palm (E-P) flux provides a realistic understanding of the middle atmospheric processes. Horizontal and vertical component of E-P flux is used to characterize the intensity of upward propagating tropospheric planetary waves. Inter annual variability reveals that the intensification planetary wave energy in the extratropical stratosphere was observed in the month of December; revert the stratospheric circulation, by creating the preconditioning state for the occurrence of stratospheric warming in January (mid-winter). After SSW, No evidence of heat flux energy is observed. This work will provide a better understanding in planetary wave - stratospheric warming mechanism.

  20. Meridional heat transport at the onset of winter stratospheric warming

    NASA Technical Reports Server (NTRS)

    Conte, M.

    1981-01-01

    A continuous vertical flow of energy toward high altitude was verified. This process produced a dynamic instability of the stratospheric polar vortex. A meridional heat transport ws primed toward the north, which generated a warming trend.

  1. Aura Microwave Limb Sounder Observations of Dynamics and Transport During the Record-Breaking 2009 Arctic Stratospheric Major Warming

    NASA Technical Reports Server (NTRS)

    Manney, Gloria L.; Schwartz, Michael J.; Krueger, Kirstin; Santee, Michelle L.; Pawson, Steven; Lee, Jae N.; Daffer, William H.; Fuller, Ryan A.; Livesey, Nathaniel J.

    2009-01-01

    A major stratospheric sudden warming (SSW) in January 2009 was the strongest and most prolonged on record. Aura Microwave Limb Sounder (MLS) observations are used to provide an overview of dynamics and transport during the 2009 SSW, and to compare with the intense, long-lasting SSW in January 2006. The Arctic polar vortex split during the 2009 SSW, whereas the 2006 SSW was a vortex displacement event. Winds reversed to easterly more rapidly and reverted to westerly more slowly in 2009 than in 2006. More mixing of trace gases out of the vortex during the decay of the vortex fragments, and less before the fulfillment of major SSW criteria, was seen in 2009 than in 2006; persistent well-defined fragments of vortex and anticyclone air were more prevalent in 2009. The 2009 SSW had a more profound impact on the lower stratosphere than any previously observed SSW, with no significant recovery of the vortex in that region. The stratopause breakdown and subsequent reformation at very high altitude, accompanied by enhanced descent into a rapidly strengthening upper stratospheric vortex, were similar in 2009 and 2006. Many differences between 2006 and 2009 appear to be related to the different character of the SSWs in the two years.

  2. Global variations of zonal mean ozone during stratospheric warming events

    NASA Technical Reports Server (NTRS)

    Randel, William J.

    1993-01-01

    Eight years of Solar Backscatter Ultraviolet (SBUV) ozone data are examined to study zonal mean variations associated with stratospheric planetary wave (warming) events. These fluctuations are found to be nearly global in extent, with relatively large variations in the tropics, and coherent signatures reaching up to 50 deg in the opposite (summer) hemisphere. These ozone variations are a manifestation of the global circulation cells associated with stratospheric warming events; the ozone responds dynamically in the lower stratosphere to transport, and photochemically in the upper stratosphere to the circulation-induced temperature changes. The observed ozone variations in the tropics are of particular interest because transport is dominated by zonal-mean vertical motions (eddy flux divergences and mean meridional transports are negligible), and hence, substantial simplifications to the governing equations occur. The response of the atmosphere to these impulsive circulation changes provides a situation for robust estimates of the ozone-temperature sensitivity in the upper stratosphere.

  3. Gravity wave activities in the stratosphere and mesosphere during sudden stratospheric warming

    NASA Astrophysics Data System (ADS)

    Li, Tao; Leblanc, Thierry; McDermid, I. Stuart; Riggin, Dennis; Fritts, Dave C.

    The gravity wave activities in the stratosphere and mesosphere of subtropics during the sudden stratospheric warming were studied using the temperature profiles measured by the Jet Propul-sion Laboratory (JPL) Rayleigh lidar at Mauna Loa Observatory (19.5N, 195.6W), Hawaii, and horizontal wind profiles measured by the MF radar at Kauai (22N, 200.2W), Hawaii. We found that the significant enhancement of gravity wave activities was observed before the sudden stratospheric warming in winter 2005/2006, followed by the decrease of activity during and after the warming. The significant change of GW activities during the warming will be dis-cussed together with the ECMWF wind in the stratosphere and MF radar mean wind in the mesosphere.

  4. Infrasonic signature of the 2009 major sudden stratospheric warming

    NASA Astrophysics Data System (ADS)

    Evers, L. G.; Siegmund, P.

    2009-12-01

    The study of infrasound is experiencing a renaissance since it was chosen as a verification technique for the Comprehensive Nuclear-Test-Ban Treaty. The success of the verification technique strongly depends on knowledge of upper atmospheric processes. The ability of infrasound to probe the upper atmosphere starts to be exploited, taking the field beyond its monitoring application. Processes in the stratosphere couple to the troposphere and influence our daily weather and climate. Infrasound delivers actual observations on the state of the stratosphere with a high spatial and temporal resolution. Here we show the infrasonic signature, passively obtained, of a drastic change in the stratosphere due to the major sudden stratospheric warming (SSW) of January 2009. With this study, we infer the enormous capacity of infrasound in acoustic remote sensing of stratospheric processes on a global scale with surface based instruments.

  5. Using finite-time Lyapunov exponents to investigate the effect of stratospheric sudden warmings on the polar vortices

    NASA Astrophysics Data System (ADS)

    Smith, M.; McDonald, A. J.

    2012-04-01

    Finite-time Lyapunov exponents are often used to measure mixing in the stratosphere and have been used to investigate the horizontal transport of trace gases near the polar vortices. A better understanding of the dynamics of the polar vortices should provide insight into the circumstances under which odd nitrogen and hydrogen produced by energetic particle precipitation (EPP) in the mesosphere and lower thermosphere (MLT) can be transported to lower levels of the atmosphere. A climatology of finite-time Lyapunov exponents for isentropic surfaces in the stratosphere ranging from 550-2300K for both the northern and southern hemispheres has been created for the observational period of the EOS-MLS instrument.The Lyapunov exponents are derived by using output from a Lagrangian trajectory model forced by data from the MERRA reanalysis. They are calculated at each point on a 2° x 4° global grid by running trajectories for two neighbouring parcels which are initially 1km apart and measuring their separation after a period of time. In order to ensure that the parcel trajectories remain close enough to each other for the exponents to be a good measure of local mixing, the distance between the parcels is periodically reset to 1km. In order to provide a consistency check Lyapunov exponents and trajectories have also been calculated at 550K using NCEP/NCAR reanalysis data. Initial comparisons suggest that the qualitative agreement is quite good between the results using the two different reanalyses. Comparison of the variations in the Lyapunov exponents and trace gas distributions using EOS-MLS data during periods where the stratospheric polar vortices are undisturbed and periods which are disturbed by stratospheric sudden warmings are also discussed. Studying how stratospheric sudden warmings (SSWs) affect the atmospheric dynamics in polar regions is particularly worthwhile since recent studies have shown that they have a significant modulating influence upon the EPP

  6. Simulation of the December 1998 Stratospheric Major Warming

    NASA Technical Reports Server (NTRS)

    Manney, G. L.; Lahoz, W. A.; Swinbank, R.; ONeill, A.; Connew, P. M.; Zurek, R. W.

    1999-01-01

    Prior to 1991, major warmings (defined by increasing zonal mean temperatures and zonal mean easterly winds from 60degN to the pole at 10 hPa) typically occurred approximately once every two Arctic winters; a major warming in mid-Dec. 1998 was the first since Feb. 1991. The Dec. 1998 warming was also the second earliest on record. The earliest, and the only other major warming on record before the end of Dec. was in early Dec 1987; prior to that, the earliest was in late Dec./early Jan. 1984-85. The 1984-85 and 1987 warmings resulted in the warmest and weakest lower stratospheric polar vortices in the 20 years before 1998-99. Fig. 1 compares temperatures and vortex strength in 1998-99 with those in the previous 20 years, using the US National Center for Environmental Prediction (NCEP) record; 1987-88 and 1984-85 are also highlighted. The Dec. 1998 warming had a more pronounced effect on mid-stratospheric temperatures than the Dec. 1987 warming (Fig. 1a), although smaller than that of warmings later in winter (e.g., 1984-85). 10-hPa temperatures fell well below average again in late Jan. 1999 and remained unusually low until an early final warming began in late Feb. 840 K PV gradients (Fig. 1c) set a record minimum in Jan. 1999, but were near average in Feb before the final warming. The effect of the Dec. 1998 warming on lower stratospheric temperatures was comparable to that of other major warmings; there was a brief period of record-high minimum 46-hPa temperatures in early Jan 1999 (Fig. 1b), and temperatures then fell to near average for a short period in mid-Feb. Lower stratospheric PV gradients were the weakest on record during the 1998-99 winter (Fig. 1d). The evolution of the vortex and minimum temperatures during 1998-99 was remarkably similar to that during 1987-88, the only previous year when a major warming was observed before the end of Dec.

  7. Stratospheric warmings: Synoptic, dynamic and general-circulation aspects

    NASA Technical Reports Server (NTRS)

    Mcinturff, R. M. (Editor)

    1978-01-01

    Synoptic descriptions consist largely of case studies, which involve a distinction between major and minor warmings. Results of energetics studies show the importance of tropospheric-stratospheric interaction, and the significance of the pressure-work term near the tropopause. Theoretical studies have suggested the role of wave-zonal flow interaction as well as nonlinear interaction between eddies, chemical and photochemical reactions, boundary forcing, and other factors. Numerical models have been based on such considerations, and these are discussed under various categories. Some indication is given as to why some of the models have been more successful than others in simulating warnings. The question of ozone and its role in warmings is briefly discussed. Finally, a broad view is taken of stratospheric warmings in relation to man's activities.

  8. Upper mesospheric lunar tides over middle and high latitudes during sudden stratospheric warming events

    NASA Astrophysics Data System (ADS)

    Chau, J. L.; Hoffmann, P.; Pedatella, N. M.; Matthias, V.; Stober, G.

    2015-04-01

    In recent years there have been a series of reported ground- and satellite-based observations of lunar tide signatures in the equatorial and low latitude ionosphere/thermosphere around sudden stratospheric warming (SSW) events. This lower atmosphere/ionosphere coupling has been suggested to be via the E region dynamo. In this work we present the results of analyzing 6 years of hourly upper mesospheric winds from specular meteor radars over a midlatitude (54°N) station and a high latitude (69°N) station. Instead of correlating our results with typical definitions of SSWs, we use the definition of polar vortex weaking (PVW) used by Zhang and Forbes. This definition provides a better representation of the strength in middle atmospheric dynamics that should be responsible for the waves propagating to the E region. We have performed a wave decomposition on hourly wind data in 21 day segments, shifted by 1 day. In addition to the radar wind data, the analysis has been applied to simulations from Whole Atmosphere Community Climate Model Extended version and the thermosphere-ionosphere-mesosphere electrodynamics general circulation model. Our results indicate that the semidiurnal lunar tide (M2) enhances in northern hemispheric winter months, over both middle and high latitudes. The time and magnitude of M2 are highly correlated with the time and associated zonal wind of PVW. At middle/high latitudes, M2 in the upper mesosphere occurs after/before the PVW. At both latitudes, the maximum amplitude of M2 is directly proportional to the strength of PVW westward wind. We have found that M2 amplitudes could be comparable to semidiurnal solar tide amplitudes, particularly around PVW and equinoxes. Besides these general results, we have also found peculiarities in some events, particularly at high latitudes. These peculiarities point to the need of considering the longitudinal features of the polar stratosphere and the upper mesosphere and lower thermosphere regions. For

  9. Discrimination of a major stratospheric warming event in February-March 1984 from earlier minor warmings

    NASA Technical Reports Server (NTRS)

    Johnson, K. W.; Quiroz, R. S.; Gelman, M. E.

    1985-01-01

    As part of its responsibility for stratospheric monitoring, the Climate Analysis Center derives time trends of various dynamic parameters from NMC stratospheric analyses. Selected figures from this stratospheric monitoring data base are published in Climate Diagnostics Bulletin in March and October, after each hemispheric winter. During the Northern Hemisphere winter of December 1983-February 1984 several warming events may be seen in the plot of 60 deg. N zonal mean temperatures for 10 mb. Minor warmings may be noted in early December, late December, mid January and early February. A major warming with the 60 deg. N zonal mean temperatures reaching -40C is observed in late February, associated with a circulation reversal. In all of the minor warming episodes, there is a polarward movement of the Aleutian anticyclone; however, at 10 mb the North Pole remains in the cyclonic circulation of the stratospheric vortex which is not displaced far from its usual position. In the case of the later February major warming, the 10 mb circulation pattern over the North Pole is anticyclonic, and the cyclonic circulation has moved to the south and east with a considerable elongation. Cross sections of heat transport and momentum transport are not dramatically different for the minor and major warming episodes.

  10. Future Changes in Major Stratospheric Warmings in CCMI Models

    NASA Technical Reports Server (NTRS)

    Ayarzaguena, B.; Langematz, U.; Polvani, L. M; Abalichin, J.; Akiyoshi, H.; Klekociuk, A.; Michou, M.; Morgenstern, O.; Oman, L.

    2015-01-01

    Major stratospheric warmings (MSWs) are one of the most important phenomena of wintertime Arctic stratospheric variability. They consist of a warming of the Arctic stratosphere and a deceleration of the polar night jet, triggered by an anomalously high injection of tropospheric wave activity into the stratosphere. Due to the relevance and the impact of MSWs on the tropospheric circulation, several model studies have investigated their potential responses to climate change. However, a wide range of results has been obtained, extending from a future increase in the frequency of MSWs to a decrease. These discrepancies might be explained by different factors such as a competition of radiative and dynamical contributors with opposite effects on the Arctic polar vortex, biases of models to reproduce the related processes, or the metric chosen for the identification of MSWs. In this study, future changes in wintertime Arctic stratospheric variability are examined in order to obtaina more precise picture of future changes in the occurrence of MSWs. In particular, transient REFC2 simulations of different CCMs involved in the Chemistry Climate Model Initiative (CCMI) are used. These simulations extend from 1960 to 2100 and include forcings by halogens and greenhouse gases following the specifications of the CCMI-REF-C2 scenario. Sea surface temperatures (SSTs) and sea-ice distributions are either prescribed from coupled climate model integrations or calculated internally in the case of fully coupled atmosphere-ocean CCMs. Potential changes in the frequency and main characteristics of MSWs in the future are investigated with special focus on the dependence of the results on the criterion for the identification of MSWs and the tropospheric forcing of these phenomena.

  11. The infrasonic signature of the 2009 major Sudden Stratospheric Warming

    NASA Astrophysics Data System (ADS)

    Evers, L.; Siegmund, P.

    2009-12-01

    The study of infrasound is experiencing a renaissance since it was chosen as a verification technique for the Comprehensive Nuclear-Test-Ban Treaty (CTBT). The success of the verification technique strongly depends on knowledge of upper atmospheric processes. The ability of infrasound to probe the upper atmosphere starts to be exploited, taking the field beyond its monitoring application. Processes in the stratosphere couple to the troposphere and influence our daily weather and climate. Infrasound delivers actual observations on the state of the stratosphere with a high spatial and temporal resolution. Here we show the infrasonic signature, passively obtained, of a drastic change in the stratosphere due to the major Sudden Stratospheric Warming (SSW) of January 2009. A major SSW started around January 15. At the altitude of 30 km, the average temperature to the north of 65N increased in one week by more than 50 deg C, leading to exceptionally high temperatures of about -20 deg C. Simultaneously, the polar vortex reversed direction from eastward to westward. The warming was accompanied by a split-up of the polar vortex and an increased amplitude of the zonal wavenumber number 2 planetary waves. Infrasound recordings on the Northern Hemisphere have been analysed. These arrays are part of the International Monitoring System (IMS) for the CTBT. Interacting oceanic waves are almost continuously emitting infrasound, where the whole atmospheric wind and temperature structure determines the detectability of these so-called microbaroms. Changes in this detectability have been associated to wind and temperatures changes around 50 km altitude due to the major SSW. With this study, we infer the enormous capacity of infrasound in passive acoustic remote sensing of stratospheric processes on a global scale with surface based instruments.

  12. Analysis of the February 2002 stratospheric warming using SABER data

    NASA Astrophysics Data System (ADS)

    Grose, W.; Lingenfelser, G.; Remsberg, E.; Harvey, V.

    2003-04-01

    The Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) instrument began acquiring data in January 2002. Version 1.01 Level 2A LTE temperature data have been compared with various correlative data sources (e.g. satellites, lidar, and falling spheres). These results generally show good agreement in the stratosphere. Synoptic temperature distributions are being generated from the SABER data using a sequential estimation technique which was developed for the use with the Nimbus 7 LIMS data. From these temperature distributions, corresponding synoptic fields of geopotential height and geostrophic winds can be obtained. The evolution of the lower stratosphere of the Northern Hemisphere during the warming of February 2002 will be analyzed using these SABER data and compared with a similar analysis using assimilated data.

  13. Large stratospheric sudden warming in Antarctic late winter and shallow ozone hole in 1988

    SciTech Connect

    Kanzawa, Hiroshi; Kawaguchi, Sadao )

    1990-01-01

    There occurred a large stratospheric sudden warming in the southern hemisphere in late winter of 1988 which competes in suddenness and size with major mid-winter warmings in the northern hemisphere. Associated with the dynamical phenomenon of the sudden warming, total ozone increased over the eastern hemispheric part of Antarctica. The sudden warming as well as other warmings which followed it made the 1988 Antarctic ozone hole shallow in depth and small in area.

  14. A review of vertical coupling in the Atmosphere-Ionosphere system: Effects of waves, sudden stratospheric warmings, space weather, and of solar activity

    NASA Astrophysics Data System (ADS)

    Yiğit, Erdal; Koucká Knížová, Petra; Georgieva, Katya; Ward, William

    2016-04-01

    This brief introductory review of some recent developments in atmosphere-ionosphere science is written for the "Vertical Coupling Special Issue" that is motivated by the 5th IAGA/ICMA/SCOSTEP Workshop on Vertical Coupling in the Atmosphere-Ionosphere System. Basic processes of vertical coupling in the atmosphere-ionosphere system are discussed, focusing on the effects of internal waves, such as gravity waves and solar tides, sudden stratospheric warmings (SSWs), and of solar activity on the structure of the atmosphere. Internal waves play a crucial role in the current state and evolution of the upper atmosphere-ionosphere system. SSW effects extend into the upper atmosphere, producing changes in the thermospheric circulation and ionospheric disturbances. Sun, the dominant energy source for the atmosphere, directly impacts the upper atmosphere and modulates wave-induced coupling. The emphasis is laid on the most recent developments in the field, while giving credits to older works where necessary. Various international activities in atmospheric vertical coupling, such as SCOSTEP's ROSMIC project, and a brief contextual discussion of the papers published in the special issue are presented.

  15. Simulations of the February 1979 stratospheric sudden warming: Model comparisons and three-dimensional evolution

    SciTech Connect

    Manney, G.L. ); Farrara, J.D.; Mechoso, C.R. )

    1994-06-01

    The evolution of the stratospheric flow during the major stratospheric sudden warming of February 1979 is studied using two primitive equation models of the stratosphere and mesosphere. The United Kingdom Meteorological Office Stratosphere-Mesosphere Model (SMM) uses log pressure as a vertical coordinate. A spectral, entropy coordinate version of the SMM (entropy coordinate model, or ECM) that has recently been developed is also used. The ECM produces a more realistic recombination and recovery of the polar vortex in the midstratosphere after the warming. Comparison of SMM simulations with forecasts performed using the University of California, Los Angeles general circulation model confirms the previously noted sensitivity of stratospheric forecasts to tropospheric forecast and emphasizes the importance of adequate vertical resolution in modeling the stratosphere. The ECM simulations provide a schematic description of the three-dimensional evolution of the polar vortex and the motion of air through it. During the warming, the two cyclonic vortices tilt westward and equatorward with height. Strong upward velocities develop in the lower stratosphere on the west (cold) side of a baroclinic zone as it forms over Europe and Asia. Strong downward velocities appear in the upper stratosphere on the east (warm) side, strengthening the temperature gradients. After the peak of the warming, vertical velocities decrease, downward velocities move into the lower stratosphere, and upward velocities move into the upper stratosphere. Transport calculations show that air with high ozone mixing ratios is advected toward the pole from low latitudes during the warming, and air with low ozone mixing ratios is transported to the midstratosphere from both higher and lower altitudes along the baroclinic zone in the polar regions. 32 refs., 23 figs., 1 tab.

  16. The role of wave-wave interaction during stratospheric splits

    NASA Astrophysics Data System (ADS)

    Miller, Andreas; Plumb, Alan

    2016-04-01

    Sudden Stratospheric Warmings (SSWs) are the most studied example of troposphere-stratosphere coupling. They are often categorized as either splits (dominated by wavenumber 2) or displacements (wavenumber 1) and many studies (e.g. Charlton and Polvani (2007)) found statistically significant differences between the zonal wind fields and associated momentum fluxes. These differences are observed from the stratosphere to the surface. Our study focuses on how wave-wave interactions within the stratosphere can determine the type of SSW. We derive an energy budget for each wavenumber that allows us to quantify the major stratospheric processes within each wavenumber as well as the energy transfer from one wavenumber into another. Calculating these budgets, using MERRA reanalysis data, we find that for many split events the energy flux into the stratosphere is predominantly in wavenumber one. Thus, wave-wave interactions within the stratosphere, which can flux energy between wavenumbers, play a key role in splitting the polar stratospheric vortex. However, the signal is weak when we calculate composites over all splits as the timing of wave-wave interactions is unrelated to classic definitions (e.g. central date) highlighting the need for a dynamically more meaningful definition of SSWs. In order to better understand the role of wave-wave interactions, we employ GFDL's FMS shallow water model to simulate the stratospheric vortex under idealized forcings (similar to Polavani et al. (1994)). Contrary to many other idealized experiments, we are able to simulate both types of warmings with pure wavenumber one or two forcings. We further explore the strength of the necessary forcing to cause stratospheric splits in relation to the state of of the polar vortex. These results are compared to the work of Matthewman and Esler (2011) on splits being a result of resonance. We finally use the energy budget described above to determine the importance of wave-wave interaction in this

  17. Thermospheric meridional circulation during sudden stratospheric warming events

    NASA Astrophysics Data System (ADS)

    Laskar, F. I.; Duggirala, P. R.

    2014-12-01

    Oxygen dayglow emission intensities, at OI 557.7, OI 630.0, and OI 777.4 nm, over a low-latitude location showed systematic enhancements in intensities throughout the daytime hours during the four sudden stratospheric warming (SSW) events that occurred in the years 2010 - 2013. The arctic latitude lower thermospheric temperatures at around 120 km altitudes obtained from the Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) instrument are found to be enhanced during SSW events and show a latitudinal gradient (temperature decreasing towards low-latitudes). Commensurately, the Thermosphere, Ionosphere, Mesosphere, Energetics and Dynamics (TIMED) Doppler Interferometer (TIDI) measurements showed equatorward winds in the mesosphere lower thermosphere (MLT) altitudes over high latitudes during these events. Both, the high-latitude lower thermospheric temperature enhancements and the MLT region equatorward winds occur simultaneously with the observed enhancements in the OI dayglow emission intensities at all the wavelengths. From these observations and other supporting observational and modeling results it is proposed that a new cell of meridional circulation in the MLT winds is set up during SSW events, which enables transport of atomic oxygen from high-to-low latitudes. Such an additional contribution of oxygen density over low-latitudes interacts with daytime lower thermospheric dynamics and is attributed to be the cause for the observed enhancement in the oxygen daytime optical emission intensities over low-latitudes. These results will presented in the light of experimental evidence to such circulation alluded to by earlier simulation studies.

  18. Ionospheric signatures of non-migrating tides and stratospheric warming

    NASA Astrophysics Data System (ADS)

    Lühr, Hermann; Stolle, Claudia; Häusler, Kathrin

    2010-05-01

    Observational data bases from recent years provided more and more evidence that climate and weather phenomena influence the dynamics of the high atmosphere. In the first part of this presentation we will address the dynamical interaction caused by non-migrating tides. Several of these tidal modes are generated in the lower atmosphere and are believed to propagate all the way up to the exosphere. Quantities that reflect the characteristics of the tides very well, are thermospheric temperature and wind. The dynamics of the neutrals is partly transferred to charged particles in the ionospheric E-layer. For that reason tidal signals are also present in the ionospheric E and F region. We show, as examples, the effect on the equatorial electrojet (EEJ), vertical plasma drift and F region electron density. Since the coupling conditions and strength between neutral and charged particles vary over the course of a day (a year, a solar cycle), the recovery of the complete ionospheric tidal signals is complex. We will present the amplitude and annual variation for the most prominent tidal components. A very recent topic of vertical coupling is the influence of sudden stratospheric warming (SSW) on the ionospheric electrodynamics. SSW has been shown to modify among others the diurnal variation of the vertical plasma drift and the electric field at equatorial latitudes. We will present global observations of the EEJ and its response to SSW events in 2002/2003. A typical feature is an enhancement of the EEJ intensity in the pre-noon hours and a reduction in the afternoon. Possible mechanisms causing these modifications will be discussed.

  19. A New Connection Between Greenhouse Warming and Stratospheric Ozone Depletion

    NASA Technical Reports Server (NTRS)

    Salawitch, R.

    1998-01-01

    The direct radiative effects of the build-up of carbon dioxide and other greenhouse gases have led to a gradual cooling of the stratosphere with largest changes in temperature occurring in the upper stratosphere, well above the region of peak ozone concentration.

  20. The interaction of radiative and dynamical processes during a simulated sudden stratospheric warming

    NASA Technical Reports Server (NTRS)

    Pierce, R. B.; Blackshear, W. T.; Fairlie, T. D.; Grose, W. L.; Turner, R. E.

    1993-01-01

    An analysis of a spontaneous sudden stratospheric warming that occurred during a 2-year integration of the Langley Research Center (LaRC) Atmospheric Simulation Model is presented. The simulated warming resembles observed 'wave 1' warmings in the Northern Hemisphere stratosphere and provides an opportunity to investigate the radiative and dynamical processes occurring during the warming event. Isentropic analysis of potential vorticity sources and sinks indicates that dynamically induced departures from radiative equilibrium play an important role in the warming event. Enhanced radiative cooling associated with a series of upper stratospheric warm pools leads to radiative dampening within the polar vortex. Within the 'surf zone' large-scale radiative cooling leads to diabatic advection of high potential vorticity air from aloft. Lagrangian area diagnostics of the simulated warming agree well with Limb Infrared Monitor of the Stratosphere (LIMS) analyses. Dynamical mixing is shown to account for the majority of the decrease in the size of the polar vortex during the simulated warming. An investigation of the nonlinear deformation of material lines that are initially coincident with diagnosed potential vorticity isopleths is conducted to clarify the relationship between the Lagrangian area diagnostics and potential vorticity advection during wave breaking events.

  1. Chemistry and transport in a three-dimensional stratospheric model - Chlorine species during a simulated stratospheric warming

    NASA Technical Reports Server (NTRS)

    Kaye, Jack A.; Rood, Richard B.

    1989-01-01

    The distributions in the stratosphere of a variety of chemical species were calculated for a 6-day period during the February 1979 stratospheric major warming, using winds derived from a spectral forecast model which included O(x), NO(x), HO(x), and ClO(x) chemistries as well as longitudinally varying reaction rate coefficients and photolysis rates for these molecules. The results obtained indicate a particular importance of chemistry and transport for the Cl-containing species ClO, ClONO2, HCl, and HOCl. Dynamical effects dominate the variability of HCl, while diurnal effects dominate that of ClONO2 and ClO. The effects of strong planetary wave activity may be seen in terms of large longitudinal variability of the total HCl and ClONO columns in the stratosphere; in the middle and high northern latitudes, it is sufficiently large to exceed the diurnal variability of the column.

  2. Signature of a sudden stratospheric warming in the near-ground 7Be flux

    NASA Astrophysics Data System (ADS)

    Pacini, A. A.; Usoskin, I. G.; Mursula, K.; Echer, E.; Evangelista, H.

    2015-07-01

    We present here an evidence that cosmogenic 7Be isotopes produced in the lower stratosphere were measured in near-ground air at Rio de Janeiro, Brazil, after the southern hemispheric Sudden Stratospheric Warming (SSW) of 2002. The analysis presented here is based on a comparison of 7Be data measured around Angra Nuclear Power Station (23°S 44°W) during the last three decades and a model estimate of the near-ground air 7Be concentration using the CRAC:7Be model of cosmogenic production together with a simplified model for atmospheric 7Be deposition that assimilates the regional precipitation data. Our results indicate that an anomalous stratosphere-troposphere coupling associated to the unique SSW of 2002 allowed stratospheric aerosols carrying 7Be to reach the ground level very quickly. This methodology points to an important use of 7Be as a quantitative tracer for stratospheric influence on near-ground air patterns.

  3. Response of the Antarctic Stratosphere to Warm Pool EI Nino Events in the GEOS CCM

    NASA Technical Reports Server (NTRS)

    Hurwitz, Margaret M.; Song, In-Sun; Oman, Luke D.; Newman, Paul A.; Molod, Andrea M.; Frith, Stacey M.; Nielsen, J. Eric

    2011-01-01

    A new type of EI Nino event has been identified in the last decade. During "warm pool" EI Nino (WPEN) events, sea surface temperatures (SSTs) in the central equatorial Pacific are warmer than average. The EI Nino signal propagates poleward and upward as large-scale atmospheric waves, causing unusual weather patterns and warming the polar stratosphere. In austral summer, observations show that the Antarctic lower stratosphere is several degrees (K) warmer during WPEN events than during the neutral phase of EI Nino/Southern Oscillation (ENSO). Furthermore, the stratospheric response to WPEN events depends of the direction of tropical stratospheric winds: the Antarctic warming is largest when WPEN events are coincident with westward winds in the tropical lower and middle stratosphere i.e., the westward phase of the quasi-biennial oscillation (QBO). Westward winds are associated with enhanced convection in the subtropics, and with increased poleward wave activity. In this paper, a new formulation of the Goddard Earth Observing System Chemistry-Climate Model, Version 2 (GEOS V2 CCM) is used to substantiate the observed stratospheric response to WPEN events. One simulation is driven by SSTs typical of a WPEN event, while another simulation is driven by ENSO neutral SSTs; both represent a present-day climate. Differences between the two simulations can be directly attributed to the anomalous WPEN SSTs. During WPEN events, relative to ENSO neutral, the model simulates the observed increase in poleward planetary wave activity in the South Pacific during austral spring, as well as the relative warming of the Antarctic lower stratosphere in austral summer. However, the modeled response to WPEN does not depend on the phase of the QBO. The modeled tropical wind oscillation does not extend far enough into the lower stratosphere and upper troposphere, likely explaining the model's insensitivity to the phase of the QBO during WPEN events.

  4. Chemistry and transport in a three-dimensional stratospheric model: Chlorine species during a simulated stratospheric warming

    SciTech Connect

    Kaye, J.A.; Rood, R.B. )

    1989-01-20

    Calculations of coupled chemistry and transport for the stratosphere are carried out for a 6-day period during the February 1979 stratospheric major warming, using winds derived from a spectral forecast model. All major families of stratospheric chemistry (odd oxygen, odd nitrogen, odd hydrogen, and odd chlorine), as well as longitudinally varying reaction rate coefficients and photolysis rates, are included in the model. Eight constituents and/or families are transported in the model; additional ones are held fixed or inferred by photochemical equilibrium approximations. Results presented include zonal mean fields, latitude-longitude distributions (and their changes with time), vertical profiles, and time series of the mixing ratios of transported constituents and families as well as of their total stratospheric column amounts. The results obtained show the relative importance of chemistry and transport for the chlorine-containing species ClO, ClONO{sub 2}, HCl, and HOCl. Dynamical effects dominate the variability of HCl, while diurnal ones dominate that of ClONO{sub 2} and ClO. Diurnal chemistry and dynamical variability are of similar magnitude for HOCl. The effects of strong planetary wave activity may be seen as large longitudinal variability of the total HCl and ClONO{sub 2} columns in the stratosphere; in middle and high northern latitudes it is sufficiently large that it exceeds the diurnal variability of the column.

  5. Contributions of stratospheric water vapor to decadal changes in the rate of global warming.

    PubMed

    Solomon, Susan; Rosenlof, Karen H; Portmann, Robert W; Daniel, John S; Davis, Sean M; Sanford, Todd J; Plattner, Gian-Kasper

    2010-03-01

    Stratospheric water vapor concentrations decreased by about 10% after the year 2000. Here we show that this acted to slow the rate of increase in global surface temperature over 2000-2009 by about 25% compared to that which would have occurred due only to carbon dioxide and other greenhouse gases. More limited data suggest that stratospheric water vapor probably increased between 1980 and 2000, which would have enhanced the decadal rate of surface warming during the 1990s by about 30% as compared to estimates neglecting this change. These findings show that stratospheric water vapor is an important driver of decadal global surface climate change. PMID:20110466

  6. Wintertime Polar Ozone Evolution during Stratospheric Vortex Break-Down

    NASA Astrophysics Data System (ADS)

    Tweedy, O.; Limpasuvan, V.; Smith, A. K.; Richter, J. H.; Orsolini, Y.; Stordal, F.; Kvissel, O.

    2011-12-01

    Stratospheric Sudden Warming (SSW) is characterized by the rapid warming of the winter polar stratosphere and the weakening of the circumpolar flow. During the onset of a major SSW (when the circumpolar flow reverses direction), the warm stratopause layer (SL) descends from its climatological position to the mid-stratosphere level. As the vortex recovers from SSW, a "new" SL forms in the mid-mesosphere region before returning to its typical level. This SL discontinuity appears in conjunction with enhanced downward intrusion of chemical species from the lower thermosphere/upper mesosphere to the stratosphere. The descended species can potentially impact polar ozone. In this study, the NCAR's Whole Atmosphere Community Climate Model (WACCM) is used to investigate the behavior of polar ozone related to major SSWs. Specifically, dynamical evolution and chemistry of NOx, CO, and O3 are examined during three realistic major SSWs and compared with a non-SSW winter season. The simulated (zonal-mean) polar ozone distribution exhibits a "primary" maximum near 40 km, a "secondary" maximum between 90-105 km, and a "tertiary" maximum near 70 km. The concentration of the secondary maximum reduces by ~1.5 parts per million by volume (ppmv) as the vortex recovers and the upper mesospheric polar easterlies return. Enhanced downwelling above the newly formed SL extends up to just above this secondary maximum (~110 km). With an averaged concentration of 2 ppmv, the tertiary ozone maximum layer displaces upward with enhanced upwelling during SSW in conjunction with the lower mesospheric cooling. The downward propagation of the stratospheric wind reversal is accompanied by CO intrusion toward the lowermost stratosphere and anomalous behavior in the primary ozone maximum. Overall, the major SSW, SL, and polar ozone evolution mimic recently reported satellite observations.

  7. Transport of polar winter lower-thermospheric Nitric Oxide to the Stratosphere

    NASA Astrophysics Data System (ADS)

    Bailey, S. M.; Thurairajah, B.; Randall, C. E.; Siskind, D. E.; Hervig, M. E.; Russell, J. M.

    2013-12-01

    Nitric oxide (NO) is a key minor constituent of the lower thermosphere. It is produced there via processes that are initiated with the ionization of N2. This ionization occurs by solar soft X-ray irradiance globally and by precipitating energetic particles in the polar regions. In the mesosphere and stratosphere NO participates in an important catalytic reaction which results in the destruction of ozone. Evidence of NO transported in the Northern Hemisphere (NH) winter from the lower thermosphere to the stratosphere has been growing in recent years. In particular, Stratospheric Sudden Warmings (SSWs) have been identified as triggers of enhanced NO descent. In this talk, we discuss observations of NO from the Solar Occultation for Ice Experiment (SOFIE) instrument on-board the Aeronomy of Ice in the Mesosphere (AIM) satellite. Six years of polar NO observations from 40 to 140 km are now available, including the NH winters of 2007-2008 through 2012-2013. SOFIE shows dramatic transport of NO in the NH winters of both 2008-2009 and 2012-2013. Both of these episodes occur after major SSWs. A weaker but very large enhancement of NO was observed in 2012 after a minor SSW. In each case, SOFIE observations of water also show evidence of transport and SOFIE observations of temperature show an elevated stratopause. These results are consistent with previous observations and the inferred role of SSWs. We will show the SOFIE observations and explore how the strength and timing of SSWs control the magnitude of the NO transport.

  8. Variance in trace constituents following the final stratospheric warming

    NASA Technical Reports Server (NTRS)

    Hess, Peter

    1990-01-01

    Concentration variations with time in trace stratospheric constituents N2O, CF2Cl2, CFCl3, and CH4 were investigated using samples collected aboard balloons flown over southern France during the summer months of 1977-1979. Data are analyzed using a tracer transport model, and the mechanisms behind the modeled tracer variance are examined. An analysis of the N2O profiles for the month of June showed that a large fraction of the variance reported by Ehhalt et al. (1983) is on an interannual time scale.

  9. On the composite response of the MLT to major sudden stratospheric warming events with elevated stratopause

    NASA Astrophysics Data System (ADS)

    Limpasuvan, Varavut; Orsolini, Yvan J.; Chandran, Amal; Garcia, Rolando R.; Smith, Anne K.

    2016-05-01

    Based on a climate-chemistry model (constrained by reanalyses below ~50 km), the zonal-mean composite response of the mesosphere and lower thermosphere (MLT) to major sudden stratospheric warming events with elevated stratopauses demonstrates the role of planetary waves (PWs) in driving the mean circulation in the presence of gravity waves (GWs), helping the polar vortex recover and communicating the sudden stratospheric warming (SSW) impact across the equator. With the SSW onset, strong westward PW drag appears above 80 km primarily from the dissipation of wave number 1 perturbations with westward period of 5-12 days, generated from below by the unstable westward polar stratospheric jet that develops as a result of the SSW. The filtering effect of this jet also allows eastward propagating GWs to saturate in the winter MLT, providing eastward drag that promotes winter polar mesospheric cooling. The dominant PW forcing translates to a net westward drag above the eastward mesospheric jet, which initiates downwelling over the winter pole. As the eastward polar stratospheric jet returns, this westward PW drag persists above 80 km and acts synergistically with the return of westward GW drag to drive a stronger polar downwelling that warms the pole adiabatically and helps reform the stratopause at an elevated altitude. With the polar wind reversal during the SSW onset, the westward drag by the quasi-stationary PW in the winter stratosphere drives an anomalous equatorial upwelling and cooling that enhance tropical stratospheric ozone. Along with equatorial wind anomalies, this ozone enhancement subsequently amplifies the migrating semidiurnal tide amplitude in the winter midlatitudes.

  10. Improved predictability of stratospheric sudden warming events in an atmospheric general circulation model with enhanced stratospheric resolution

    NASA Astrophysics Data System (ADS)

    Marshall, Andrew G.; Scaife, Adam A.

    2010-08-01

    The impact of stratospheric resolution on the predictability of stratospheric sudden warming (SSW) events and their effect on European climate is cleanly assessed in two versions of the Hadley Center's atmospheric climate model, Hadley Center global environmental model. The standard 38-level version of the model extends to an altitude of 39 km (˜3 mbar) while the extended 60-level version has enhanced stratospheric resolution and reaches 84 km altitude (˜0.004 mbar). We show that the L60 model captures SSW events earlier than the L38 model (12 days before an event compared with 8 days) and influences the simulation of European surface winter cold spells at seasonal time scales, highlighting the benefit of high vertical resolution and daily initialization for seasonal forecasting. This is likely due to earlier initialization of the downward-propagating SSW signal in the higher-top L60 model. We suggest however that the increased lead time for predicting SSW events is unlikely to be improved much further by raising the model lid above the L60 model domain.

  11. The Remarkable 2003--2004 Winter and Other Recent Warm Winters in the Arctic Stratosphere Since the Late 1990s

    NASA Technical Reports Server (NTRS)

    Manney, Gloria L.; Kruger, Kirstin; Sabutis, Joseph L.; Sena, Sara Amina; Pawson, Steven

    2005-01-01

    The 2003-2004 Arctic winter was remarkable in the approximately 50-year record of meteorological analyses. A major warming beginning in early January 2004 led to nearly 2 months of vortex disruption with high-latitude easterlies in the middle to lower stratosphere. The upper stratospheric vortex broke up in late December, but began to recover by early January, and in February and March was the strongest since regular observations began in 1979. The lower stratospheric vortex broke up in late January. Comparison with 2 previous years, 1984-1985 and 1986-1987, with prolonged midwinter warming periods shows unique characteristics of the 2003-2004 warming period: The length of the vortex disruption, the strong and rapid recovery in the upper stratosphere, and the slow progression of the warming from upper to lower stratosphere. January 2004 zonal mean winds in the middle and lower stratosphere were over 2 standard deviations below average. Examination of past variability shows that the recent frequency of major stratospheric warmings (7 in the past 6 years) is unprecedented. Lower stratospheric temperatures were unusually high during 6 of the past 7 years, with 5 having much lower than usual potential for polar stratospheric cloud (PSC) formation and ozone loss (nearly none in 1998-1999, 2001-2002, and 2003-2004, and very little in 1997-1998 and 2000-2001). Middle and upper stratospheric temperatures, however, were unusually low during and after February. The pattern of 5 of the last 7 years with very low PSC potential would be expected to occur randomly once every 850 years. This cluster of warm winters, immediately following a period of unusually cold winters, may have important implications for possible changes in interannual variability and for determination and attribution of trends in stratospheric temperatures and ozone.

  12. The Remarkable 2003-2004 Winter and Other Recent Warm Winters in the Arctic Stratosphere Since the Late 1990s

    NASA Technical Reports Server (NTRS)

    Manney, Gloria L.; Krueger, Kirstin; Sabutis, Joseph L.; Sena, Sara Amina; Pawson, Steven

    2004-01-01

    The 2003-2004 Arctic winter was remarkable in the 40-year record of meteorological analyses. A major warming beginning in early January 2004 led to nearly two months of vortex disruption with high-latitude easterlies in the middle to lower stratosphere. The upper stratospheric vortex broke up in late December, but began to recover by early January, and in February and March was the strongest since regular observations began in 1979. The lower stratospheric vortex broke up in late January. Comparison with two previous years, 1984-1985 and 1986-1987, with prolonged mid-winter warming periods shows unique characteristics of the 2003-2004 warming period: The length of the vortex disruption, the strong and rapid recovery in the upper stratosphere, and the slow progression of the warming from upper to lower stratosphere. January 2004 zonal mean winds in the middle and lower stratosphere were over two standard deviations below average. Examination of past variability shows that the recent frequency of major stratospheric warmings (seven in the past six years) is unprecedented. Lower stratospheric temperatures were unusually high during six of the past seven years, with five having much lower than usual potential for PSC formation and ozone loss (nearly none in 1998-1999, 2001-2002 and 2003-2004, and very little in 1997-1998 and 2000-2001). Middle and upper stratospheric temperatures, however, were unusually low during and after February. The pattern of five of the last seven years with very low PSC potential would be expected to occur randomly once every approximately 850 years. This cluster of warm winters, immediately following a period of unusually cold winters, may have important implications for possible changes in interannual variability and for determination and attribution of trends in stratospheric temperatures and ozone.

  13. Troposphere-Stratosphere Coupled Chemistry-Climate Interactions: From Global Warming Projections to Air Quality

    NASA Astrophysics Data System (ADS)

    Nowack, P. J.; Abraham, N. L.; Maycock, A. C.; Braesicke, P.; Pyle, J. A.

    2015-12-01

    Changes in stratospheric composition can affect tropospheric composition and vice versa. Of particular interest are trace gas concentrations at the interface between these two atmospheric layers in the tropical upper troposphere and lower stratosphere (UTLS). This is due to the crucial importance of composition changes in the UTLS for the global energy budget. In a recent study (Nowack et al., 2015), we provided further evidence that composition changes in the tropical UTLS can significantly affect global warming projections. Using a state-of-the-art atmosphere-ocean chemistry-climate model, we found a ~20% smaller global warming in response to an abrupt 4xCO2 forcing if composition feedbacks were included in the calculations as compared to simulations in which composition feedbacks were not considered. We attributed this large difference in surface warming mainly to circulation-driven decreases in tropical UTLS ozone and related changes in stratospheric water vapor, partly counteracted by simultaneous changes in ice clouds. Here, we explain why this result is expected to differ between models and how, inter alia, tropospheric chemical mechanisms can contribute to this uncertainty. We highlight that improving our understanding of processes in the tropical UTLS and their representation in Earth system models remains a key challenge in climate research.Finally, taking geoengineering as a new example, we show that changes in the stratosphere can have an impact on air quality in the troposphere. In particular, we explain for a simple solar radiation management scenario how changes in surface ozone can be linked to changes in meteorology and composition in the troposphere and stratosphere. In conclusion, we highlight the importance of considering air quality impacts when evaluating a variety of geoengineering scenarios. Reference: Nowack, P.J., Abraham, N.L., Maycock, A.C., Braesicke, P., Gregory, J.M., Joshi, M.M., Osprey, A., and Pyle, J.A. Nature Climate Change 5, 41

  14. Behavior of the sodium and hydroxyl nighttime emissions during a stratospheric warming

    NASA Technical Reports Server (NTRS)

    Walker, J. D.; Reed, E. I.

    1975-01-01

    The behavior of the sodium and hydroxyl nighttime emissions during a stratospheric warming has been studied principally by use of data from the airglow photometers on the OGO-4 satellite. It was found that during the late stages of a major warming, both emissions increase appreciably, with the sodium emission returning to normal levels prior to the decrease in hydroxyl emission. The emission behaviors are attributed to temperature and density variations from 70 to 94 km, and a one-dimensional hydrostatic model for that altitude range is used to calculate the effects on the emissions and on the mesospheric ozone densities.

  15. Rapid increases of CO and H2O in the tropical lower stratosphere during January 2010 stratospheric sudden warming event

    NASA Astrophysics Data System (ADS)

    Eguchi, Nawo; Kodera, Kunihiko; Ueyama, Rei; Li, Qian

    2014-05-01

    A potential transport mechanism of various tracers from the tropical troposphere to the lower stratosphere (LS) across the tropical tropopause layer (TTL) is the overshooting convective clouds which inject air with tropospheric characteristics (high CO, high H2O, low O3) into the LS over a period of a few days. Evidence of such convective intrusions extending up to the 90 hPa level are observed over the southern African continent at the end of January 2010 in MLS and CALIOP satellite measurements. Rapid increases of CO and water vapor concentrations over Africa are associated with increased convective activity over the region a few days prior to the onset of stratospheric sudden warming (SSW) event and contribute to enhancements in their zonal tropical mean concentrations during January and February 2010. The modulation of tropical upwelling by SSW appears to force stronger and deeper tropical convection, particularly in the Southern Hemisphere tropics. The January 2010 SSW event induced the lowest recorded LS temperature in MLS history (2004-13), allowing an unprecedented clear detection of stratosphere-troposphere exchange process by way of CO, H2O and O3 intrusions. The present study suggests that short duration, overshooting clouds can have a large impact on the zonally averaged fields of LS composition (zonally-averaged tracer fields in the tropical LS). In this presentation, we present the simulated CO, water vapor and ozone mixing ratios during Jan 2010 SSW using GEOS-Chem model. We further investigate the transport pathways based on trajectory analysis of air parcels in convective regions of the tropics.

  16. Sudden Stratospheric Warming (SSW) and its immediate and broader influence on tropical dynamics using COSMIC Observations

    NASA Astrophysics Data System (ADS)

    Dhaka, Surendra

    2016-07-01

    We have analyzed temperature changes in troposphere and stratosphere from polar to tropical region during major sudden stratospheric warming (SSW) using data derived from COSMIC over a period of 2007-2014. During peak period of SSW, a large variability noted in temperature structure, rise in temperature occurred down to the tropopause height (~8 km height) in polar region. At around 40 km altitudes (as data is available to this height), temperature increased by several tens of degrees within few days of SSW. After SSW termination, temperature decreased up to ~ 80°C in strong SSW cases. After about a week of SSW event, descending cold anomalies emerged at polar region. These features are emerging normally known as polar night jet oscillations (PJO). The cooling phase was much longer along with large spatial coverage than the warm phase. Due to SSW, polar T-CPT and H-CPT alter significantly. As a consequence of SSW, bottom of stratospheric region expands and hence the tropospheric region shrunk by the same height. A rapid atmospheric response is identified between polar and tropical region possibly through set up of strong meridional circulation. During occurrence of SSW, at 40 km altitude in polar region, large increase in temperature noted, while in the tropics temperature dropped at similar heights. After termination of SSW, descending warm anomalies observed over the tropical region for a longer duration, while the long cold phase persisted at the polar region. These warm anomalies at tropical region are much longer and deeper in comparison to those of the cold anomalies. It is concluded that SSW event at polar region connects to the entire tropical tropopause region across the equator in SH up to 40° S. Hence these processes need to be understood thoroughly to contribute to the temperature change.

  17. Wave Signatures in the Polar Mesopause Region during the January, 2009 Sudden Stratospheric Warming

    NASA Astrophysics Data System (ADS)

    Ward, W. E.; Kristoffersen, S.; Vail, C.

    2012-12-01

    Observations on a two minute cadence at the Polar Environment Atmospheric Research Laboratory (PEARL, Eureka, Nunavut, 80N) with an all sky imager and a Doppler Imaging Interferometer were taken during the January, 2009 major stratospheric warming. These observations complement temperature and irradiance measurments previously reported from the same location. Oscillations with periods of 4 days, 2.5 days, 24 hours, 16 hours 12 hours and 8 hours are observed during this warming period. In addition shorter period oscillations in the airglow observations and wind observations are observed. This paper summarizes these observations and delineates the evolution of these features and the large scale winds during this warming event.Meridional winds from Doppler shifts in the oxygen green line airglow observed with the ERWIN II instrument from January 16-31, 2009. Individual points are observations every 2 minutes with an error of 2 m/s.

  18. Mesosphere-to-stratosphere descent of odd nitrogen in February-March 2009 after sudden stratospheric warming

    NASA Astrophysics Data System (ADS)

    Salmi, S.-M.; Verronen, P. T.; Thölix, L.; Kyrölä, E.; Backman, L.; Karpechko, A. Yu.; Seppälä, A.

    2011-01-01

    We use the 3-D FinROSE chemistry transport model (CTM) and ACE-FTS (Atmospheric Chemistry Experiment Fourier Transform Spectrometer) observations to study the connection between atmospheric dynamics and NOx descent during early 2009 in the northern polar region. We force the model NOx at 80 km poleward of 60° N with ACE-FTS observations and then compare the model results with observations at lower altitudes. Low geomagnetic indices indicate absence of local NOx production in early 2009, which gives a good opportunity to study the effects of atmospheric transport on polar NOx. No in-situ production of NOx by energetic particle precipitation is therefore included. This is the first model study using ECMWF (The European Centre for Medium-Range Weather Forecasts) data up to 80 km and simulating the exceptional winter of 2009 with one of the strongest major sudden stratospheric warmings (SSW). The model results show a strong NOx descent in February-March 2009 from the upper mesosphere to the stratosphere after the major SSW. Both observations and model results suggest an increase of NOx to 150-200 ppb (i.e. by factor of 50) at 65 km due to the descent following the SSW. The model, however, underestimates the amount of NOx around 55 km by 40-60 ppb. The results also show that the chemical loss of NOx was insignificant i.e. NOx was mainly controlled by the dynamics. Both ACE-FTS observations and FinROSE show a decrease of ozone of 20-30% at 30-50 km after mid-February to mid-March. However, these changes are not related to the NOx descent, but are due to activation of the halogen chemistry.

  19. Role of Stratospheric Water Vapor in Global Warming from GCM Simulations Constrained by MLS Observation

    NASA Astrophysics Data System (ADS)

    Wang, Y.; Stek, P. C.; Su, H.; Jiang, J. H.; Livesey, N. J.; Santee, M. L.

    2014-12-01

    Over the past century, global average surface temperature has warmed by about 0.16°C/decade, largely due to anthropogenic increases in well-mixed greenhouse gases. However, the trend in global surface temperatures has been nearly flat since 2000, raising a question regarding the exploration of the drivers of climate change. Water vapor is a strong greenhouse gas in the atmosphere. Previous studies suggested that the sudden decrease of stratospheric water vapor (SWV) around 2000 may have contributed to the stall of global warming. Since 2004, the SWV observed by Microwave Limb Sounder (MLS) on Aura satellite has shown a slow recovery. The role of recent SWV variations in global warming has not been quantified. We employ a coupled atmosphere-ocean climate model, the NCAR CESM, to address this issue. It is found that the CESM underestimates the stratospheric water vapor by about 1 ppmv due to limited representations of the stratospheric dynamic and chemical processes important for water vapor variabilities. By nudging the modeled SWV to the MLS observation, we find that increasing SWV by 1 ppmv produces a robust surface warming about 0.2°C in global-mean when the model reaches equilibrium. Conversely, the sudden drop of SWV from 2000 to 2004 would cause a surface cooling about -0.08°C in global-mean. On the other hand, imposing the observed linear trend of SWV based on the 10-year observation of MLS in the CESM yields a rather slow surface warming, about 0.04°C/decade. Our model experiments suggest that SWV contributes positively to the global surface temperature variation, although it may not be the dominant factor that drives the recent global warming hiatus. Additional sensitivity experiments show that the impact of SWV on surface climate is mostly governed by the SWV amount at 100 hPa in the tropics. Furthermore, the atmospheric model simulations driven by observed sea surface temperature (SST) show that the inter-annual variation of SWV follows that of SST

  20. Signature of a Sudden Stratospheric Warming in the near-ground 7Be flux.

    NASA Astrophysics Data System (ADS)

    Pacini, A. A.

    2015-12-01

    We present here a study of the impact of one Sudden Stratospheric Warming (SSW) upon the atmospheric vertical dynamics based on 7Be measurements in near ground air, using both numerical and conceptual. In late September 2002, an unprecedented SSW event occurred in the southern hemisphere (SH), causing changes in the tropospheric circulation, ozone depletion and weakening of the polar jet in the mesosphere. There is an observational evidence suggesting that anomalies in the stratosphere play an important role in driving tropospheric weather producing tropospheric changes that can persists for up to 60 days in NH and up to about 90 days in the SH, as observed after the 2002 SSW (Thompson et al., 2005). Radioactive environmental techniques for tracing large-scale air-mass transport have been applied in studies of atmospheric dynamics for decades and they are becoming more and more precise due to the improvement of the instrumental sensitivity and associated modeling. Temporal variations of the cosmogenic 7Be concentration in the near-surface atmosphere can provide information on the air mass dynamics, precipitation patterns, stratosphere-troposphere coupling and cosmic ray variations. The present study is based on an analysis of 7Be concentration measured in near-ground air in the city of Angra dos Reis, Rio de Janeiro state, Brazil between 1987 and 2009. Using a simplified tropospheric 7Be model deposition based on a two-layer transport model, Pacini (2011) reported that the occurrence of strong downward air flux leave an imprint of the 3D motion of air masses to the near-ground air 7Be data in the studied region. In this work, we have further developed the two-layer model by adding one more layer: the lower stratosphere (LS). In normal conditions, the contribution of the LS 7Be to the near-ground isotopic variability would be very small. On the other hand, stratospheric source can be crucial for the SSW event, indicating that a strong stratospheric air intrusion

  1. A comparison of SAGE I data during the stratospheric warming of February-March, 1979

    NASA Technical Reports Server (NTRS)

    Nagatani, R. M.; Mccormick, M. P.; Mcmaster, L. R.

    1985-01-01

    The fine scale vertical structure of SAGE I ozone and aerosol data during a stratospheric warming is investigated using meteorological and SBUV ozone data. By stratifying the ozone and aerosol data for a limited time period, a comparison of the structure of profiles becomes possible under different meteorological conditions. For example, the cold air region shows more laminated structures than the other regions. In addition, vertical motions calculated at the same locations as the SAGE profiles show that they are consistent with variances found in the ozone and aerosol data.

  2. A Lagrangian analysis of a sudden stratospheric warming - Comparison of a model simulation and LIMS observations

    NASA Technical Reports Server (NTRS)

    Pierce, R. B.; Remsberg, Ellis E.; Fairlie, T. D.; Blackshear, W. T.; Grose, William L.; Turner, Richard E.

    1992-01-01

    Lagrangian area diagnostics and trajectory techniques are used to investigate the radiative and dynamical characteristics of a spontaneous sudden warming which occurred during a 2-yr Langley Research Center model simulation. The ability of the Langley Research Center GCM to simulate the major features of the stratospheric circulation during such highly disturbed periods is illustrated by comparison of the simulated warming to the observed circulation during the LIMS observation period. The apparent sink of vortex area associated with Rossby wave-breaking accounts for the majority of the reduction of the size of the vortex and also acts to offset the radiatively driven increase in the area occupied by the 'surf zone'. Trajectory analysis of selected material lines substantiates the conclusions from the area diagnostics.

  3. First forecast of a sudden stratospheric warming with a coupled whole-atmosphere/ionosphere model IDEA

    NASA Astrophysics Data System (ADS)

    Wang, H.; Akmaev, R. A.; Fang, T.-W.; Fuller-Rowell, T. J.; Wu, F.; Maruyama, N.; Iredell, M. D.

    2014-03-01

    We present the first "weather forecast" with a coupled whole-atmosphere/ionosphere model of Integrated Dynamics in Earth's Atmosphere (IDEA) for the January 2009 Sudden Stratospheric Warming (SSW). IDEA consists of the Whole Atmosphere Model and Global Ionosphere-Plasmasphere model. A 30 day forecast is performed using the IDEA model initialized at 0000 UT on 13 January 2009, 10 days prior to the peak of the SSW. IDEA successfully predicts both the time and amplitude of the peak warming in the polar cap. This is about 2 days earlier than the National Centers for Environmental Prediction operational Global Forecast System terrestrial weather model forecast. The forecast of the semidiurnal, westward propagating, zonal wave number 2 (SW2) tide in zonal wind also shows an increase in the amplitude and a phase shift to earlier hours in the equatorial dynamo region during and after the peak warming, before recovering to their prior values about 15 days later. The SW2 amplitude and phase changes are shown to be likely due to the stratospheric ozone and/or circulation changes. The daytime upward plasma drift and total electron content in the equatorial American sector show a clear shift to earlier hours and enhancement during and after the peak warming, before returning to their prior conditions. These ionospheric responses compare well with other observational studies. Therefore, the predicted ionospheric response to the January 2009 SSW can be largely explained in simple terms of the amplitude and phase changes of the SW2 zonal wind in the equatorial E region.

  4. Estimating efficiency of the controlled sulphur emissions in the stratosphere to mitigate global warming

    NASA Astrophysics Data System (ADS)

    Eliseev, A. V.; Mokhov, I. I.; Chernokulsky, A. V.; Karpenko, A. A.

    2008-12-01

    An attempt is made to estimate an efficiency of sulphur loading in the stratosphere to mitigate global warming employing a large ensemble of numerical experiments with the climate model of intermediate complexity developed at the A.M.Obukhov Institute of Atmospheric Physics RAS (IAP RAS CM). In this ensemble, the model is forced by the historical+SRES A1B anthropogenical greenhouse gases+tropospheric sulphates scenario for 1860--2100 with an additional sulphur emissions in the stratosphere started in 2012. Different ensemble members were constructed by varying emission intensity, residence time and optical properites of stratospheric sulphur. Given global loading of the sulphates in the stratosphere, at the global basis the most efficient latitudinal distribution of geoengineering aerosols is that peaked between 50° N and 70° N. At regional scale other latitudinal distributions may be superior. In particular, the distributions peaked in the tropics are the most efficient to reduce warming in the subtropics and the distrbutions peaked at 50° N is the superior to mitigate annual warming in Siberia. However, an approach of geoengineering has inherent flaws. First, it results in a widespread dryness. The second, and perhaps more dangerous, issue is due to the fast removal of geoengineering climatic effect if the corresponding emissions are stopped. After this stop, climate trajectory returns to the non--mitigated one within few decades. This results in a necessity to continue a geoengineering mitigation very long in future. Third, estimated sulphur emissions amount 5-10 TgS/yr in 2050 and 10-14 TgS/yr in 2100 which is not a small part of the current emissions of tropospheric sulphates. The latter may lead to marked enhancement of the tropospheric sulphates pollution. The results obtained with the IAP RAS CM are further interpreted by making use of an energy--balance climate model. As a whole, the results obtained with this simpler model support conclusions made on

  5. Mesosphere-to-stratosphere descent of odd nitrogen in February-March 2009 after sudden stratospheric warming

    NASA Astrophysics Data System (ADS)

    Salmi, S.-M.; Verronen, P. T.; Thölix, L.; Kyrölä, E.; Backman, L.; Karpechko, A. Yu.; Seppälä, A.

    2011-05-01

    We use the 3-D FinROSE chemistry transport model (CTM) and Atmospheric Chemistry Experiment Fourier Transform Spectrometer (ACE-FTS) observations to study connections between atmospheric dynamics and middle atmospheric NOx (NOx = NO + NO2) distribution. Two cases are considered in the northern polar regions: (1) descent of mesospheric NOx in February-March 2009 after a major sudden stratospheric warming (SSW) and, for comparison, (2) early 2007 when no NOx descent occurred. The model uses the European Centre for Medium-Range Weather Forecasts (ECMWF) operational data for winds and temperature, and we force NOx at the model upper altitude boundary (80 km) with ACE-FTS observations. We then compare the model results with ACE-FTS observations at lower altitudes. For the periods studied, geomagnetic indices are low, which indicates absence of local NOx production by particle precipitation. This gives us a good opportunity to study effects of atmospheric transport on polar NOx. The model results show no NOx descent in 2007, in agreement with ACE-FTS. In contrast, a large amount of NOx descends in February-March 2009 from the upper to lower mesosphere at latitudes larger than 60° N, i.e. inside the polar vortex. Both observations and model results suggest NOx increases of 150-200 ppb (i.e. by factor of 50) at 65 km due to the descent. However, the model underestimates the amount of NOx around 55 km by 40-60 ppb. According to the model results, chemical loss of NOx is insignificant during the descent period, i.e. polar NOx is mainly controlled by dynamics. The descent is terminated and the polar NOx amounts return to pre-descent levels in mid-March, when the polar vortex breaks. The break-up prevents the descending NOx from reaching the upper stratosphere, where it could participate in catalytic ozone destruction. Both ACE-FTS observations and FinROSE show a decrease of ozone of 20-30 % at 30-50 km from mid-February to mid-March. In the model, these ozone changes are not

  6. Towards a physical understanding of stratospheric cooling under global warming through a process-based decomposition method

    NASA Astrophysics Data System (ADS)

    Yang, Yang; Ren, R.-C.; Cai, Ming

    2016-02-01

    The stratosphere has been cooling under global warming, the causes of which are not yet well understood. This study applied a process-based decomposition method (CFRAM; Coupled Surface-Atmosphere Climate Feedback Response Analysis Method) to the simulation results of a Coupled Model Intercomparison Project, phase 5 (CMIP5) model (CCSM4; Community Climate System Model, version 4), to demonstrate the responsible radiative and non-radiative processes involved in the stratospheric cooling. By focusing on the long-term stratospheric temperature changes between the "historical run" and the 8.5 W m-2 Representative Concentration Pathway (RCP8.5) scenario, this study demonstrates that the changes of radiative radiation due to CO2, ozone and water vapor are the main divers of stratospheric cooling in both winter and summer. They contribute to the cooling changes by reducing the net radiative energy (mainly downward radiation) received by the stratospheric layer. In terms of the global average, their contributions are around -5, -1.5, and -1 K, respectively. However, the observed stratospheric cooling is much weaker than the cooling by radiative processes. It is because changes in atmospheric dynamic processes act to strongly mitigate the radiative cooling by yielding a roughly 4 K warming on the global average base. In particular, the much stronger/weaker dynamic warming in the northern/southern winter extratropics is associated with an increase of the planetary-wave activity in the northern winter, but a slight decrease in the southern winter hemisphere, under global warming. More importantly, although radiative processes dominate the stratospheric cooling, the spatial patterns are largely determined by the non-radiative effects of dynamic processes.

  7. Stratospheric Impacts on Arctic Sea Ice

    NASA Astrophysics Data System (ADS)

    Reichler, Thomas

    2016-04-01

    Long-term circulation change in the stratosphere can have substantial effects on the oceans and their circulation. In this study we investigate whether and how sea ice at the ocean surface responds to intraseasonal stratospheric variability. Our main question is whether the surface impact of stratospheric sudden warmings (SSWs) is strong and long enough to affect sea ice. A related question is whether the increased frequency of SSWs during the 2000s contributed to the rapid decrease in Arctic sea ice during this time. To this end we analyze observations of sea ice, NCEP/NCAR reanalysis, and a long control integration with a stratospherically-enhanced version of the GFDL CM2.1 climate model. From both observations and the model we find that stratospheric extreme events have a demonstrable impact on the distribution of Arctic sea ice. The areas most affected are near the edge of the climatological ice line over the North Atlantic, North Pacific, and the Arctic Ocean. The absolute changes in sea ice coverage amount to +/-10 %. Areas and magnitudes of increase and decrease are about the same. It is thus unlikely that the increased SSW frequency during the 2000s contributed to the decline of sea ice during that period. The sea ice changes are consistent with the impacts of a negative NAO at the surface and can be understood in terms of (1) dynamical change due to altered surface wind stress and (2) thermodynamical change due to altered temperature advection. Both dynamical and thermodynamical change positively reinforce each other in producing sea change. A simple advection model is used to demonstrate that most of the sea ice change can be explained from the sea ice drift due to the anomalous surface wind stress. Changes in the production or melt of sea ice by thermodynamical effects are less important. Overall, this study adds to an increasing body of evidence that the stratosphere not only impacts weather and climate of the atmosphere but also the surface and

  8. Upper atmosphere response to stratosphere sudden warming: Local time and height dependence simulated by GAIA model

    NASA Astrophysics Data System (ADS)

    Liu, Huixin; Jin, Hidekatsu; Miyoshi, Yasunobu; Fujiwara, Hitoshi; Shinagawa, Hiroyuki

    2013-02-01

    Abstract The whole atmosphere model GAIA is employed to shed light on atmospheric response to the 2009 major <span class="hlt">stratosphere</span> sudden <span class="hlt">warming</span> (SSW) from the ground to exobase. Distinct features are revealed about SSW impacts on thermospheric temperature and density above 100 km altitude. (1) The effect is primarily quasi-semidiurnal in tropical regions, with <span class="hlt">warming</span> in the noon and pre-midnight sectors and cooling in the dawn and dusk sectors. (2) This pattern exists at all altitudes above 100 km, with its phase being almost constant above 200 km, but propagates downward in the lower thermosphere between 100 and 200 km. (3) The northern polar region experiences <span class="hlt">warming</span> in a narrow layer between 100 and 130 km, while the southern polar region experiences cooling throughout 100-400 km altitudes. (4) The global net thermal effect on the atmosphere above 100 km is a cooling of approximately -12 K. These characteristics provide us with an urgently needed global context to better connect and understand the increasing upper atmosphere observations during SSW events.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015AGUFM.A33K0344C&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015AGUFM.A33K0344C&link_type=ABSTRACT"><span id="translatedtitle">The Plunger Hypothesis: an overview of a new theory of <span class="hlt">stratosphere</span>-troposphere dynamic coupling</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Clark, S.; Baldwin, M. P.; Stephenson, D.</p> <p>2015-12-01</p> <p>I will demonstrate the advantages of a new method of quantifying polar <span class="hlt">stratosphere</span>-troposphere coupling by considering large-scale movements of mass into and out of the polar <span class="hlt">stratosphere</span>. This project aims to use these mass movements to explain pressure and temperature anomalies throughout the polar troposphere and lower <span class="hlt">stratosphere</span> in the aftermath of extreme <span class="hlt">stratospheric</span> events. We hypothesise that these mass movements are induced by deposition of momentum by breaking waves in the <span class="hlt">stratosphere</span>, slowing the wintertime polar vortex, and so are associated with sudden <span class="hlt">stratospheric</span> <span class="hlt">warmings</span> (<span class="hlt">SSWs</span>). Such a mass movement in the upper <span class="hlt">stratosphere</span> acts to compress the polar atmosphere below it in the manner of a plunger. In this way the pressure anomaly in the upper polar <span class="hlt">stratosphere</span> 'controls' the pressure and temperature anomalies below by adiabatic compression of the polar atmospheric column. Better understanding this method of control will allow us to use <span class="hlt">stratospheric</span> data to improve medium-range forecasting ability in the troposphere. One of the key innovations featured in this project is considering pressure and temperature fields at fixed geopotential surfaces, allowing for the easy observation of mass movement into and out of a polar cap region (which we have defined as north of 65N) as a function of altitude. Reanalysis data considered in this manner demonstrates a relationship between tropospheric pressure anomalies and <span class="hlt">stratospheric</span> anomalies in the polar cap, and so a way to predict tropospheric variability given <span class="hlt">stratospheric</span> information. This work forms part of a three and a half year PhD project.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFMSA41B2340M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFMSA41B2340M"><span id="translatedtitle">Lunar tidal effects during the 2013 <span class="hlt">stratospheric</span> sudden <span class="hlt">warming</span> as simulated by the TIME-GCM</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Maute, A. I.; Forbes, J. M.; Zhang, X.; Fejer, B. G.; Yudin, V. A.; Pedatella, N. M.</p> <p>2015-12-01</p> <p><span class="hlt">Stratospheric</span> Sudden <span class="hlt">Warmings</span> (SSW) are associated with strong planetary wave activity in the winterpolar <span class="hlt">stratosphere</span> which result in a very disturbed middle atmosphere. The changes in the middle atmospherealter the propagation conditions and the nonlinear interactions of waves and tides, and result in SSW signals in the upper atmosphere in e.g., neutral winds, electric fields, ionospheric currents and plasma distribution. The upper atmosphere changes can be significant at low-latitudes even during medium solar flux conditions. Observationsalso reveal a strong lunar signal during SSW periods in the low latitude vertical drifts and in ionospheric quantities. Forbes and Zhang [2012] demonstrated that during the 2009 SSW period the Pekeris resonance peak of the atmosphere was altered such that the M2 and N2 lunar tidal componentsgot amplified. This study focuses on the effect of the lunar tidal forcing on the thermosphere-ionosphere system during theJanuary 2013 SSW period. We employthe NCAR Thermosphere-Ionosphere-Mesosphere-Electrodynamics General Circulation Model (TIME-GCM)with a nudging scheme using the Whole-Atmosphere-Community-Climate-Model-Extended (WACCM-X)/Goddard Earth Observing System Model, Version 5 (GEOS5) results to simulate the effects of meteorological forcing on the upper atmosphere. Additionally lunar tidal forcingis included at the lower boundary of the model. To delineate the lunar tidal effects a base simulation without lunar forcingis employed. Interestingly, Jicamarca observations of that period reveal a suppression of the daytime vertical drift before and after the drift enhancement due the SSW. The simulation suggests that the modulation of the vertical driftmay be caused by the interplay of the migrating solar and lunar semidiurnal tide, and therefore can only be reproduced by the inclusion of both lunar and solar tidal forcings in the model. In this presentation the changes due to the lunar tidal forcing will be quantified, and compared</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010cosp...38..982P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010cosp...38..982P"><span id="translatedtitle">The polar Sudden <span class="hlt">Stratospheric</span> <span class="hlt">Warming</span> (SSW) and it's possible manifestations in the equatorial Mesosphere-Thermosphere-Ionosphere</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Pant, Tarun</p> <p></p> <p>In this study, the variations in daytime mesopause temperature and the Equatorial Electrojet over equator during Sudden <span class="hlt">Stratospheric</span> <span class="hlt">Warming</span> (SSW) events over high latitudes have been investigated. To reflect upon the <span class="hlt">stratospheric</span> conditions NCEP-NCAR reanalysis data have also been used. This study indicates a possible dynamical coupling between the two regions through the planetary wave activity. The amplified wave signatures of quasi-16 day period are seen in the equatorial mesopause temperature and zonal mean polar <span class="hlt">stratospheric</span> temperature (at 10 hPa) during the course of SSW. The possibility that the planetary waves over the polar <span class="hlt">stratosphere</span>, which play an important role in the generation of SSW, could also have contribu-tion from the tropics has been indicated through numerical simulations in the past [Dunkerton, 1981], but due to the paucity of global measurements it could not be established unequivocally. These simulations also indicated the presence of a zero-wind line whose real counterparts were not observed in the atmosphere. The NCEP-NCAR reanalysis of <span class="hlt">stratospheric</span> wind and tem-peratures clearly shows that (i) a dynamical feature similar to the zero-wind line appears over the tropics 60 days prior to the major <span class="hlt">warming</span> and progresses poleward and, (ii) enhanced PW activity is seen almost simultaneously. This study shows that the recent SSW events had tropical associations. Further, favored occurrences of Equatorial Counter Electrojets (CEJs) with a quasi 16-day periodicity over Trivandrum (8.5oN, 76.5oE, 0.5oN diplat.) in association with the polar <span class="hlt">Stratospheric</span> Sudden <span class="hlt">Warming</span> (SSW) events are presented. It is seen that, the <span class="hlt">stratospheric</span> temperature at 30 km over Trivandrum showed a sudden cooling prior to the SSW and the first bunch of CEJs occurred around this time. <span class="hlt">Stratospheric</span> zonal mean zonal wind at 30 km exhibited a distinctly different pattern during the SSW period. These circula-tion changes are proposed to be conducive for the upward</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008cosp...37.2343P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008cosp...37.2343P"><span id="translatedtitle">The polar Sudden <span class="hlt">Stratospheric</span> <span class="hlt">Warming</span> (SSW) and it's possible manifestations in the equatorial Mesosphere-Thermosphere-Ionosphere</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Pant, Tarun; Vineeth, C.; Sridharan, R.</p> <p></p> <p>In this study, the variations in daytime mesopause temperature and the Equatorial Electrojet over equator during Sudden <span class="hlt">Stratospheric</span> <span class="hlt">Warming</span> (SSW) events over high latitudes have been investigated. To reflect upon the <span class="hlt">stratospheric</span> conditions NCEP-NCAR reanalysis data have also been used. This study indicates a possible dynamical coupling between the two regions through the planetary wave activity. The amplified wave signatures of quasi-16 day period are seen in the equatorial mesopause temperature and zonal mean polar <span class="hlt">stratospheric</span> temperature (at 10 hPa) during the course of SSW. The possibility that the planetary waves over the polar <span class="hlt">stratosphere</span>, which play an important role in the generation of SSW, could also have contribution from the tropics has been indicated through numerical simulations in the past [Dunkerton, 1981], but due to the paucity of global measurements it could not be established unequivocally. These simulations also indicated the presence of a zero-wind line whose real counterparts were not observed in the atmosphere. The NCEP-NCAR reanalysis of <span class="hlt">stratospheric</span> wind and temperatures clearly shows that (i) a dynamical feature similar to the zero-wind line appears over the tropics 60 days prior to the major <span class="hlt">warming</span> and progresses poleward and, (ii) enhanced PW activity is seen almost simultaneously. This study shows that the recent SSW events had tropical associations. Further, favored occurrences of Equatorial Counter Electrojets (CEJs) with a quasi 16-day periodicity over Trivandrum (8.5oN, 76.5oE, 0.5oN diplat.) in association with the polar <span class="hlt">Stratospheric</span> Sudden <span class="hlt">Warming</span> (SSW) events are presented. It is seen that, the <span class="hlt">stratospheric</span> temperature at 30 km over Trivandrum showed a sudden cooling prior to the SSW and the first bunch of CEJs occurred around this time. <span class="hlt">Stratospheric</span> zonal mean zonal wind at 30 km exhibited a distinctly different pattern during the SSW period. These circulation changes are proposed to be conducive for the upward</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015EGUGA..1710094S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015EGUGA..1710094S"><span id="translatedtitle">Subtropical influence on January 2009 major sudden <span class="hlt">stratospheric</span> <span class="hlt">warming</span> event: diagnostic analysis</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Schneidereit, Andrea; Peters, Dieter; Grams, Christian; Wolf, Gabriel; Riemer, Michael; Gierth, Franziska; Quinting, Julian; Keller, Julia; Martius, Olivia</p> <p>2015-04-01</p> <p>In January 2009 a major sudden <span class="hlt">stratospheric</span> <span class="hlt">warming</span> (MSSW) event occurred with the strongest NAM anomaly ever observed at 10 hPa. Also <span class="hlt">stratospheric</span> Eliassen-Palm flux convergence and zonal mean eddy heat fluxes of ultra-long waves at 100 hPa layer were unusually strong in the mid-latitudes just before and after the onset of the MSSW. Beside internal interactions between the background flow and planetary waves and between planetary waves among themselves the subtropical tropospheric forcing of these enhanced heat fluxes is still an open question. This study investigates in more detail the dynamical reasons for the pronounced heat fluxes based on ERA-Interim re-analysis data. Investigating the regional contributions of the eddy heat flux to the northern hemispheric zonal mean revealed a distinct spatial pattern with maxima in the Eastern Pacific/North America and the Eastern North Atlantic/ Europe in that period. The first region is related with an almost persistent tropospheric blocking high (BH) over the Gulf of Alaska dominating the upper-level flow and the second region with a weaker BH over Northern Europe. The evolution of the BH over the Gulf of Alaska can be explained by a chain of tropospheric weather events linked to and maintained by subtropical and tropical influences: MJO (phase 7-8) and the developing cold phase of ENSO (La Niña), which are in coherence over the Eastern Pacific favor enhanced subtropical baroclinicity. In turn extratropical cyclone activity increases and shifts more poleward associated with an increase of the frequency of <span class="hlt">warm</span> conveyor belts (WCB). These WCBs support enhanced poleward directed eddy heat fluxes in Eastern Pacific/North-American region. The Eastern North Atlantic/European positive heat flux anomaly is associated with a blocking high over Scandinavia. This BH is maintained by an eastward propagating Rossby wave train, emanating from the block over the Gulf of Alaska. Eddy feedback processes support this high pressure</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016ACP....16.4885G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016ACP....16.4885G"><span id="translatedtitle">Influence of the sudden <span class="hlt">stratospheric</span> <span class="hlt">warming</span> on quasi-2-day waves</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gu, Sheng-Yang; Liu, Han-Li; Dou, Xiankang; Li, Tao</p> <p>2016-04-01</p> <p>The influence of the sudden <span class="hlt">stratospheric</span> <span class="hlt">warming</span> (SSW) on a quasi-2-day wave (QTDW) with westward zonal wave number 3 (W3) is investigated using the Thermosphere-Ionosphere-Mesosphere Electrodynamics General Circulation Model (TIME-GCM). The summer easterly jet below 90 km is strengthened during an SSW, which results in a larger refractive index and thus more favorable conditions for the propagation of W3. In the winter hemisphere, the Eliassen-Palm (EP) flux diagnostics indicate that the strong instabilities at middle and high latitudes in the mesopause region are important for the amplification of W3, which is weakened during SSW periods due to the deceleration or even reversal of the winter westerly winds. Nonlinear interactions between the W3 and the wave number 1 stationary planetary wave produce QTDW with westward zonal wave number 2 (W2). The meridional wind perturbations of the W2 peak in the equatorial region, while the zonal wind and temperature components maximize at middle latitudes. The EP flux diagnostics indicate that the W2 is capable of propagating upward in both winter and summer hemispheres, whereas the propagation of W3 is mostly confined to the summer hemisphere. This characteristic is likely due to the fact that the phase speed of W2 is larger, and therefore its waveguide has a broader latitudinal extension. The larger phase speed also makes W2 less vulnerable to dissipation and critical layer filtering by the background wind when propagating upward.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012EGUGA..1410911K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012EGUGA..1410911K"><span id="translatedtitle">Simultaneous microwave measurements of middle atmospheric ozone and temperature during sudden <span class="hlt">stratospheric</span> <span class="hlt">warming</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kulikov, M. Y.; Krasil'nikov, A. A.; Shvetsov, A. A.; Mukhin, D. N.; Fedoseev, L. I.; Ryskin, V. G.; Belikovich, M. V.; Karashtin, D. A.; Kukin, L. M.; Feigin, A. M.</p> <p>2012-04-01</p> <p>At the present time we carry out the experimental campaign aimed to study the response of middle atmosphere on current sudden <span class="hlt">stratospheric</span> <span class="hlt">warming</span> above Nizhny Novgorod, Russia (56N, 44E). The equipment consists of two room-temperature radiometers which specially have been designed to detect emission ozone line at 110.8 GHz and atmospheric radiation in the frequency range 52.5 - 54.5 GHz accordingly. Two digital fast Fourier transform spectroanalyzers developed by "Acqiris" are employed for signal analysis in the intermediate frequency range 0.05-1 GHz with the effective resolution 61 KHz. For retrieval vertical profiles of ozone and temperature from radiometric data we apply novel method based on Bayesian approach to inverse problems which assumes a construction of probability distribution of the characteristics of retrieved profiles with taking into account measurement noise and available a priori information about possible distributions of ozone and temperature in the middle atmosphere. Here we are going to introduce the fist results of the campaign in comparison with Aura MLS data and temperature maps from High Resolution Transport Model MIMOSA. The work was done under support of the RFBR (projects 11-05-97050 and 12-05-00999).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFMSA41B2341G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFMSA41B2341G"><span id="translatedtitle">Deep Ionospheric Hole Created by Sudden <span class="hlt">Stratospheric</span> <span class="hlt">Warming</span> in the Nighttime Ionosphere</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Goncharenko, L. P.</p> <p>2015-12-01</p> <p>Multiple observational studies have demonstrated large ionospheric variations associated with sudden <span class="hlt">stratospheric</span> <span class="hlt">warming</span> (SSW) events during the daytime, but only limited evidence of ionospheric disturbances during the night-time was reported up to now. We focus on the American longitudinal sector with its extensive observational network and utilize observations by GPS receivers, three digisondes located at low and middle latitudes, and Arecibo and Millstone Hill incoherent scatter radars. The study focuses on a major SSW event of January 2013 to investigate large-scale disturbances in the nighttime ionosphere. We report a deep decrease in TEC that reaches a factor of 2-6 as compared to the background level and is observed between the local midnight and local sunrise (6-12UT). This decrease is observed for several consecutive days in the range of latitudes from ~55oS to ~45oN. It is accompanied by a strong downward plasma motion and a significant decrease in ion temperature, as observed by both Arecibo and Millstone Hill radars. We discuss variations in electric field and F-region dynamics as possible drivers of this behavior.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2014cosp...40E2462P&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2014cosp...40E2462P&link_type=ABSTRACT"><span id="translatedtitle">Ionospheric variability over Indian low latitude linked with the 2009 sudden <span class="hlt">stratospheric</span> <span class="hlt">warming</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Patra, Amit; Alex, Sobhana; Samireddipalle, Sripathi; Peddapati, PavanChaitanya</p> <p></p> <p>In this paper, we analyze radar observations of ExB drift and plasma irregularities, ionosonde observations of E- and F-layer parameters including spread F, and magnetic field observations made from Indian low latitudes linked with the 2009 sudden <span class="hlt">stratospheric</span> <span class="hlt">warming</span> (SSW) event. ExB drift variations presented here are the first of their kind from the Indian sector as far as the effect of SSW is concerned. Difference of magnetic fields observed from the equator and low latitude (∆H) and ExB drift show linear relation and both show remarkably large positive values in the morning and negative values in the afternoon exhibiting semidiurnal behavior. Remarkable changing patterns in the critical frequency of F2 layer (foF2) and F3 layer (foF3) were observed after the occurrence of SSW. Large variations with quasi-16-day periodicity were observed in ∆H, foF2 and foF3. Both semidiurnal and quasi-16-day wave modulation observed after the 2009 SSW event are consistent with those reported earlier. We also noted quasi-6 day variations in ∆H and foF2 soon after the SSW commencement, not much reported before. During the counter-electrojet events linked with the SSW event, while equatorial Es (Esq) disappeared as expected, there were no blanketing Es (Esb), a finding not reported and discussed earlier. Esb was also not formed at the off-equatorial location, indicating the absence of required vertical wind shear, but E region plasma irregularities were observed by the ionosonde and radar with a close relationship between the two. Weak F region irregularities were observed in the post-midnight hours and case studies suggest the possible role of SSW related background electric field in the manifestation of post-midnight F region irregularities.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2014JGRA..119.4044P&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2014JGRA..119.4044P&link_type=ABSTRACT"><span id="translatedtitle">Ionospheric variability over Indian low latitude linked with the 2009 sudden <span class="hlt">stratospheric</span> <span class="hlt">warming</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Patra, A. K.; Pavan Chaitanya, P.; Sripathi, S.; Alex, S.</p> <p>2014-05-01</p> <p>In this paper, we analyze radar observations of E × B drift and plasma irregularities, ionosonde observations of E and F layer parameters including spread F, and magnetic field observations made from Indian low latitudes linked with the 2009 sudden <span class="hlt">stratospheric</span> <span class="hlt">warming</span> (SSW) event. E × B drift variations presented here are the first of their kind from the Indian sector as far as the effect of SSW is concerned. Difference of magnetic fields observed from the equator and low-latitude (∆H) and E × B drift show linear relation, and both show remarkably large positive values in the morning and negative values in the afternoon exhibiting semidiurnal behavior. Remarkable changing patterns in the critical frequency of F2 layer (foF2) and F3 layer (foF3) were observed after the occurrence of SSW. Large variations with quasi 16 day periodicity were observed in ∆H, foF2, and foF3. Both semidiurnal and quasi 16 day wave modulation observed after the 2009 SSW event are consistent with those reported earlier. We also noted quasi 6 day variations in ∆H and foF2 soon after the SSW commencement, not much reported before. During the counterelectrojet events linked with the SSW event, while equatorial Es (Esq) disappeared as expected, there were no blanketing Es (Esb), a finding not reported and discussed earlier. Esb was also not formed at the off-equatorial location, indicating the absence of required vertical wind shear, but E region plasma irregularities were observed by the ionosonde and radar with a close relationship between the two. Weak F region irregularities were observed in the postmidnight hours, and case studies suggest the possible role of SSW-related background electric field in the manifestation of postmidnight F region irregularities.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EGUGA..18..982G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EGUGA..18..982G"><span id="translatedtitle">Worldwide impacts of sudden <span class="hlt">stratospheric</span> <span class="hlt">warmings</span> on the ionosphere and thermosphere</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Goncharenko, Larisa; Coster, Anthea; Zhang, Shun-Rong; Erickson, Phillip; Aponte, Nestor; Harvey, V. Lynn; Pedatella, Nicholas; Maute, Astrid</p> <p>2016-04-01</p> <p>Recent studies have demonstrated large variations in the low-latitude ionosphere during strong, persistent meteorological disturbances known as sudden <span class="hlt">stratospheric</span> <span class="hlt">warmings</span>. Several possible lower/upper atmosphere coupling mechanisms were identified, including changes in the dynamics of the background neutral atmosphere, modification of solar and lunar tides, and subsequent variations in electric field. We extend these studies using observations by GNSS TEC receivers, by several ionosondes located at low, middle, and high latitudes, and by Jicamarca, Arecibo and Millstone Hill incoherent scatter radars to investigate large-scale ionospheric disturbances for several SSW events. To separate ionospheric anomalies associated with SSW from regular ionospheric behavior, we develop an empirical model of ionospheric parameters (TEC, NmF2) using available long-term data records (10-40 years of data depending on the instrument). The models describe variations in parameters for each longitude/latitude bin (or ionosonde location) as a function of solar activity, geomagnetic activity, day of year, and local time. Ionospheric anomalies are obtained as the difference between the observations and the empirical model. Ionospheric anomalies are observed for both major and minor SSW events, reaching 50-100% variation from expected seasonal behavior for major SSW events and 30-60% variation for minor SSW events. The largest variations in the daytime TEC and NmF2 are observed both in the crests of equatorial ionization anomaly and at 40-60S (geodetic). Recent expansion of GNSS TEC receiver network to high latitudes in the southern hemisphere indicates that SSW anomalies are communicated across the globe and associated with ionospheric disturbances even over Antarctica. Observational studies focused on SSW events present an important opportunity to better understand processes governing the behavior of the Earth's ionosphere and thermosphere. We use examples of observations from</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016cosp...41E1115L&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016cosp...41E1115L&link_type=ABSTRACT"><span id="translatedtitle">Vertical and Horizontal Coupling of Atmospheres During Sudden <span class="hlt">Stratospheric</span> <span class="hlt">Warming</span> Events</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Laskar, Fazlul; Pallamraju, Duggirala; Chau, Jorge L.</p> <p>2016-07-01</p> <p>The dynamics of neutral behavior over low- mid- and high-latitudes and electrodynamic behavior over low-latitude middle and upper atmosphere during sudden <span class="hlt">stratospheric</span> <span class="hlt">warming</span> (SSW) events have been investigated in this study. Over a decade long datasets of equatorial electrojet (EEJ) and total electron content (TEC) from Indian longitudes at low-latitudes have been used for studying the electrodynamical behavior. From the amplitudes of quasi-16 day waves in these two datasets it has been observed that the vertical coupling is stronger during strong major SSW events and weaker but significant for the minor SSW events. The neutral dynamical behavior has been investigated using both optical and radio measurements. The oxygen dayglow emission intensities from low-latitudes showed enhancements in and around the duration of SSW occurrences. Evidences of equatorward winds at mesosphere lower thermosphere altitude from TIMED-TIDI and lower-thermospheric temperature enhancements from TIMED-SABER are observed in the duration of enhancement in dayglow emission intensities. The results from these three independent datasets and discrete results from earlier modeling and observational studies suggest that an equatorward circulation in the winds is set up in the MLT-region during SSW. The low-latitude oxygen intensity enhancements during SSW are attributed to be due to the transport of oxygen from high- to low-latitudes. Enhanced semi-diurnal tides are also observed during the SSW events in the low-latitude dayglow emission intensities and specular meteor radar-based mid- and high-latitude horizontal winds. These results will be presented in the context of neutral and wave dynamics of the mesosphere-thermosphere region during SSW events.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_3");'>3</a></li> <li><a href="#" onclick='return showDiv("page_4");'>4</a></li> <li class="active"><span>5</span></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_5 --> <div id="page_6" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_4");'>4</a></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li class="active"><span>6</span></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="101"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014cosp...40E1342J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014cosp...40E1342J"><span id="translatedtitle">Atmospheric and Ionospheric Response to <span class="hlt">Stratospheric</span> Sudden <span class="hlt">Warming</span> of January 2013.</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Jonah, Olusegun Folarin; De Paula, Eurico; Kherani, Esfhan alam; Severino, Dutra</p> <p></p> <p>In this work, we examine the atmospheric and ionospheric responses to the January 2013 <span class="hlt">Stratospheric</span> Sudden <span class="hlt">Warming</span> (SSW) event. To examine the atmospheric and ionospheric behavior during this event, three main parameters are used: (1) Total Electron Content (TEC) collected from the International Global Positioning System (IGS) and from the Brazilian Network of Continuous Monitoring (RBMC) stations, (2) Daytime ExB vertical drift derived from the magnetometers located at the equatorial station Alta Floresta (9.9ºS, 55.9ºW, dip lat: 1.96º) and an off equatorial station Cuiaba (15.3ºS, 56.0ºW, dip lat: 7.10º), both in the Brazilian sector, (3) The Mesosphere and lower thermosphere (MLT) meridional and zonal wind components measured by the Meteor Radar located at the southern mid-latitude Santa Maria (29.4ºS, 53.3ºW, dip lat: 17.8º). We identify the anomalous variation in ExB drift based on later local time migration of peak value with SSW days, as reported recently by Goncharenko et al [2013]. A novel feature of the present study is the identification of the similar migration pattern in the TEC anomaly, in spite that the simultaneous solar-flux increase during the SSW event also acts as another dominant forcing. Other novel features are the amplification of the 13-16 day periods in the TEC anomaly during the SSW days, and simultaneous amplification of these periods in the meridional and zonal wind components in the MLT region. These aspects reveal the presence of coupled atmosphere-ionosphere dynamics during the SSW event and the amplification of the lunar and/or solar tidal component, a characteristic which is recently reported from the electrojet current measurements [Park et al, 2012].</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014JGRA..119.4973J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014JGRA..119.4973J"><span id="translatedtitle">Atmospheric and ionospheric response to sudden <span class="hlt">stratospheric</span> <span class="hlt">warming</span> of January 2013</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Jonah, O. F.; Paula, E. R.; Kherani, E. A.; Dutra, S. L. G.; Paes, R. R.</p> <p>2014-06-01</p> <p>In this work, we examine the atmospheric and ionospheric responses to the January 2013 sudden <span class="hlt">stratospheric</span> <span class="hlt">warming</span> (SSW) event. To examine the atmospheric and ionospheric behavior during this event, three main parameters are used (1) Total Electron Content (TEC) collected from the International Global Positioning System and from the Brazilian Network of Continuous Monitoring stations, (2) daytime E × B vertical drift derived from the magnetometers located at the equatorial station Alta Floresta (9.9°S, 55.9°W, dip latitude 1.96°) and an off-equatorial station Cuiaba (15.3°S, 56.0°W, dip latitude 7.10°), both in the Brazilian sector, (3) the mesosphere and lower thermosphere (MLT) meridional and zonal wind components measured by the Meteor Radar located at the southern midlatitude Santa Maria (29.4°S, 53.3°W, dip latitude 17.8°). We identify the anomalous variation in E × B drift based on later local-time migration of peak value with SSW days. A novel feature of the present study is the identification of the similar migration pattern in the TEC anomaly, in spite that the simultaneous solar flux increases during the SSW event. Other novel features are the amplification of the 13-16 day period in the TEC anomaly during the SSW days and simultaneous amplification of this period in the meridional and zonal wind components in the MLT region, as far as 30°S. These aspects reveal the presence of coupled atmosphere-ionosphere dynamics during the SSW event and the amplification of the lunar and/or solar tidal component, a characteristic which is recently reported from the electrojet current measurements.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20140012679','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20140012679"><span id="translatedtitle">The Major <span class="hlt">Stratospheric</span> Sudden <span class="hlt">Warming</span> of January 2013: Analyses and Forecasts in the GEOS-5 Data Assimilation System</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Coy, Lawrence; Pawson, Steven</p> <p>2014-01-01</p> <p>We examine the major <span class="hlt">stratosphere</span> sudden <span class="hlt">warming</span> (SSW) that occurred on 6 January 2013, using output from the NASA Global Modeling and Assimilation Office (GMAO) GEOS-5 (Goddard Earth Observing System) near-real-time data assimilation system (DAS). Results show that the major SSW of January 2013 falls into the vortex splitting type of SSW, with the initial planetary wave breaking occurring near 10 hPa. The vertical flux of wave activity at the tropopause responsible for the SSW occurred mainly in the Pacific Hemisphere, including the a pulse associated with the preconditioning of the polar vortex by wave 1 identified on 23 December 2012. While most of the vertical wave activity flux was in the Pacific Hemisphere, a rapidly developing tropospheric weather system over the North Atlantic on 28 December is shown to have produced a strong transient upward wave activity flux into the lower <span class="hlt">stratosphere</span> coinciding with the peak of the SSW event. In addition, the GEOS-5 5-day forecasts accurately predicted the major SSW of January 2013 as well as the upper tropospheric disturbances responsible for the <span class="hlt">warming</span>. The overall success of the 5-day forecasts provides motivation to produce regular 10-day forecasts with GEOS-5, to better support studies of <span class="hlt">stratosphere</span>-troposphere interaction.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2014cosp...40E2255N&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2014cosp...40E2255N&link_type=ABSTRACT"><span id="translatedtitle">The Tropospheric cooling and the <span class="hlt">Stratospheric</span> <span class="hlt">warming</span> at Tirunelveli during the Annular Solar Eclipse of 15 January, 2010</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Nelli, Narendra Reddy; Choudhary, Raj Kumar; Rao, Kusuma</p> <p></p> <p>The UTLS region, a transition region between the troposphere and the <span class="hlt">stratosphere</span> is of concern to climate scientists as its temperature variations are crucial in determining the water vapour and the other trace gases transport between the two regions, which inturn determine the radiative <span class="hlt">warming</span> and cooling of the troposphere and the <span class="hlt">stratosphere</span>. To examine, the temperature variations from surface to lower <span class="hlt">stratosphere</span>,a major experiment facility was set up for upper air and surface measurements during the Annular Solar Eclipse (ASE) of January 15, 2010 at Tirunelveli (8.72 N, 77.81 E) located in 94% eclipse path in the southern peninsular India. The instruments,namely, 1. high resolution GPS radiosonde system, 2. an instrumented 15 m high Mini Boundary Layer Mast, 3. an instrumented 1 m high Near Surface Mast (NSM), radiation and other ground sensors were operated during the period 14-19 Jan, 2010. The ASE of January 15, 2010 was unique being the longest in duration (9 min, 15.3 sec) among the similar ones that occurred in the past. The major inference from an analysis of surface and upper air measurements is the occurrence of troposphere cooling during the eclipse with the peak cooling of 5 K at 15 km height with respect to no-eclispe conditions. Also, intense <span class="hlt">warming</span> in the <span class="hlt">stratosphere</span> is observed with the peak <span class="hlt">warming</span> of 7 K at 19 km height.Cooling of the Troposphere as the eclipse advanced and the revival to its normal temperature is clearly captured in upper air measurements. The downward vertical velocities observed at 100 hPa in NCEP Re-analyses, consistent with the tropospheric cooling during the ASE window, may be causing the <span class="hlt">stratospheric</span> <span class="hlt">warming</span>. Partly, these vertical velocities could be induced by the mesoscale circulation associated with the mesoscale convective system that prevailed parallel to the eclipse path as described in METEOSAT imageries of brightness temperatures from IR channel. Further analysis is being carried out to quantify the</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016cosp...41E2113Y&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016cosp...41E2113Y&link_type=ABSTRACT"><span id="translatedtitle">Gravity wave effects in the thermosphere during sudden <span class="hlt">stratospheric</span> <span class="hlt">warmings</span> and vertical coupling between the lower and upper atmosphere</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yiǧit, Erdal; Medvedev, Alexander S.</p> <p>2016-07-01</p> <p>Gravity waves are primarily generated in the lower atmosphere, propagate upward, and have profound effects not only in the middle atmosphere but also at much higher altitudes. However, their effects in the upper atmosphere beyond the turbopause ( 105 km) have not been sufficiently studied. Using a general circulating model extending from the lower atmosphere to upper thermosphere and incorporating a whole atmosphere nonlinear parameterization of small-scale GWs developed by Yiǧit et al. (2008)}, we demonstrate that not only GWs penetrate into the thermosphere above the turbopause but also produce substantial dynamical and thermal effects that are comparable to ion drag and Joule heating. During sudden <span class="hlt">stratospheric</span> <span class="hlt">warmings</span>, GW propagation in the thermosphere is enhanced by more than a factor of three (Yiǧit and Medvedev, 2012)}, producing appreciable body forcing of up to 600 m s^{-1} day^{-1} around 250-300 km. The resultant impact on the variability of the thermospheric circulation can exceed ± 50% depending on the phase of the sudden <span class="hlt">warming</span> (Yiǧit et al., 2014)}. References: Yiǧit, E., and A. S. Medvedev (2012), Gravity waves in the thermosphere during a sudden <span class="hlt">stratospheric</span> <span class="hlt">warming</span>, Geophys. Res. Lett., 39, L21101, doi:10.1029/2012GL053812. Yiǧit, E., A. D. Aylward, and A. S. Medvedev (2008), Parameterization of the effects of vertically propagating gravity waves for thermosphere general circulation models: Sensitivity study, J. Geophys. Res., 113, D19106, doi:10.1029/2008JD010135. Yiǧit, E., A. S. Medvedev, S. L. England, and T. J. Immel (2014), Simulated vari- ability of the high-latitude thermosphere induced by small-scale gravity waves during a sudden <span class="hlt">stratospheric</span> <span class="hlt">warming</span>, J. Geophys. Res. Space Physics, 119, doi:10.1002/2013JA019283.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015EGUGA..17.7215K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015EGUGA..17.7215K"><span id="translatedtitle">Definition of <span class="hlt">Stratospheric</span> Sudden <span class="hlt">Warming</span> Events for Multi-Model Analysis and Its Application to the CMIP5</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kim, Junsu; Son, Seok-Woo; Park, Hyo-Seok</p> <p>2015-04-01</p> <p>The onset of major <span class="hlt">stratospheric</span> sudden <span class="hlt">warming</span> (SSW) events has been often defined as the date when the westerly at 10 hPa and 60°N turns to easterly during winter, corresponding to warmer polar <span class="hlt">stratosphere</span> than mid latitudes. This simple definition effectively detects the observed characteristics of SSW, but its application to climate models, which have different background flow and temporal variability, is often challenging. For example, the model whose <span class="hlt">stratospheric</span> mean wind is too weak tends to overestimate the frequency of zonal-wind reversal and SSW events. In this study we propose a simple definition of major SSW events that is applicable to multi-model analysis. Specifically, SSW events are defined when the tendency of zonal-mean zonal wind at 10 hPa at 60°N crosses -1 m/s/day within 30 to 40 days while growing in magnitude. This tendency-based definition, which is independent of mean wind, is applied to both ERA40 reanalysis and CMIP5 models. The models are further grouped into the high-top models with a well-resolved <span class="hlt">stratosphere</span> and low-top models with a relatively simple <span class="hlt">stratosphere</span>. A new definition successfully reproduces the mean frequency of SSW events that is identified by wind reversal approach, i.e., about 6 events per decade in ERA40. High-top models well capture this frequency. Although low-top models underestimate the frequency, in contrast to previous studies, the difference to high-top models is not statistically significant. Likewise, no significant difference is found in the downward coupling in the high-top and low-top models. These results indicate that model vertical resolution itself may not be a key factor in simulating SSW events and the associated downward coupling.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFMSA23A2038L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFMSA23A2038L"><span id="translatedtitle"><span class="hlt">Stratospheric</span> Sudden <span class="hlt">Warming</span> Effects on the Ionospheric Migrating Tides during 2008-2010 observed by FORMOSAT-3/COSMIC</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lin, J.; Lin, C.; Chang, L. C.; Liu, H.; Chen, W.; Chen, C.; Liu, J. G.</p> <p>2013-12-01</p> <p>In this paper, ionospheric electron densities obtained from radio occultation soundings of FORMOSAT-3/COSMIC are decomposed into their various constituent tidal components for studying the <span class="hlt">stratospheric</span> sudden <span class="hlt">warming</span> (SSW) effects on the ionosphere during 2008-2010. The tidal analysis indicates that the amplitudes of the zonal mean and major migrating tidal components (DW1, SW2 and TW3) decrease around the time of the SSW, with phase/time shifts in the daily time of maximum around EIA and middle latitudes. Meanwhile consistent enhancements of the SW2 and nonmigrating SW1 tides are seen after the <span class="hlt">stratospheric</span> temperature increase. In addition to the amplitude changes of the tidal components, well matched phase shifts of the ionospheric migrating tides and the <span class="hlt">stratospheric</span> temperatures are found for the three SSW events, suggesting a good indicator of the ionospheric response. Although the conditions of the planetary waves and the mean winds in the middle atmosphere region during the 2008-2010 SSW events may be different, similar variations of the ionospheric tidal components and their associated phase shifts are found. Futher, these ionospheric responses will be compared with realistic simulations of Thermosphere-Ionosphere-Mesophere-Electrodynamics General Circulation Model (TIME-GCM) by nudging Modern-Era Retrospective analysis for Research and Applications (MERRA) data.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/27051997','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/27051997"><span id="translatedtitle">Dynamics of 2013 Sudden <span class="hlt">Stratospheric</span> <span class="hlt">Warming</span> event and its impact on cold weather over Eurasia: Role of planetary wave reflection.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Nath, Debashis; Chen, Wen; Zelin, Cai; Pogoreltsev, Alexander Ivanovich; Wei, Ke</p> <p>2016-01-01</p> <p>In the present study, we investigate the impact of <span class="hlt">stratospheric</span> planetary wave reflection on tropospheric weather over Central Eurasia during the 2013 Sudden <span class="hlt">Stratospheric</span> <span class="hlt">Warming</span> (SSW) event. We analyze EP fluxes and Plumb wave activity fluxes to study the two and three dimensional aspects of wave propagation, respectively. The 2013 SSW event is excited by the combined influence of wavenumber 1 (WN1) and wavenumber 2 (WN2) planetary waves, which makes the event an unusual one and seems to have significant impact on tropospheric weather regime. We observe an extraordinary development of a ridge over the Siberian Tundra and the North Pacific during first development stage (last week of December 2012) and later from the North Atlantic in the second development stage (first week of January 2013), and these waves appear to be responsible for the excitation of the WN2 pattern during the SSW. The wave packets propagated upward and were then reflected back down to central Eurasia due to strong negative wind shear in the upper <span class="hlt">stratospheric</span> polar jet, caused by the SSW event. Waves that propagated downward led to the formation of a deep trough over Eurasia and brought extreme cold weather over Kazakhstan, the Southern part of Russia and the Northwestern part of China during mid-January 2013. PMID:27051997</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012EGUGA..1412921S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012EGUGA..1412921S"><span id="translatedtitle">HALO aircraft measurements of East Asian anthropogenic SO2 import into the lower <span class="hlt">stratosphere</span> by a <span class="hlt">warm</span> conveyor belt uplift</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Schlager, H.; Arnold, F.; Aufmhoff, H.; Baumann, R.; Pirjola, L.; Roiger, A.; Sailer, T.; Wirth, M.; Schumann, U.</p> <p>2012-04-01</p> <p>We report on a case study of anthropogenic SO2 pollution transport into the lower <span class="hlt">stratosphere</span> from East Asian source regions. The pollution layer was observed over Central Europe by measurements from the new German research aircraft HALO. The layer contained enhanced SO2, HNO3 and water vapor and caused increased Lidar backscatter radiation. Meteorological analysis and air mass transport and dispersion model simulations reveal that the detected pollutants were released from ground-based sources in East-China, South-Korea, and Japan. The pollution plume was uplifted by a <span class="hlt">warm</span> conveyor belt associated with a West-Pacific cyclone and finally injected into the lower <span class="hlt">stratosphere</span>. Our HALO measurements were performed 5 days after the air mass uplift event, when significant parts of the Northern Hemisphere were already covered by the pollution plume. Accompanying trajectory chemistry and aerosol box model simulations indicate that H2SO4/H2O aerosol droplets were generated in the SO2-rich plume and grew to sizes large enough to explain the observed increased Lidar backscatter signal. Implications of the SO2 transport pathway into the lower <span class="hlt">stratosphere</span> presented in this study will be discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016cosp...41E2004V&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016cosp...41E2004V&link_type=ABSTRACT"><span id="translatedtitle">Total Electron Content (TEC) disturbances over Brazilian region during the minor sudden <span class="hlt">stratospheric</span> <span class="hlt">warming</span> (SSW 2012) event of January 2012</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Vieira, Francisco; Fagundes, Paulo Roberto; Kavutarapu, Venkatesh; Gil Pillat, Valdir</p> <p>2016-07-01</p> <p>The effects of Sudden <span class="hlt">Stratospheric</span> <span class="hlt">Warming</span> on ionosphere have been investigated by several scientists, using different observational techniques and model simulations. However, the 2011-2012 minor event is one of those that are less studied. Since, the zonal westward wind is slowed without reversing to eastward, this SSW was consider as a minor event. The <span class="hlt">stratospheric</span> temperature started increasing on December 26, 2011, reached its peak on January 18, 2012, and afterwards started decreasing slowly. In addition, there was moderate geomagnetic storm on January 22-25, 2012, after the SSW temperature peak. In the present study, the GPS-TEC measurements from a network of 72 receivers over the Brazilian region are considered. This network of 72 GPS-TEC locations lies between 5 N and 30 S (35 degrees) latitudes and 35 W and 65 W (30 degrees) longitudes. Further, two chains of GPS receivers are used to study the response of Equatorial Ionization Anomaly (EIA) changes in the Brazilian East and West sectors, as well as its day-to-day variability before and during the SSW2012. It was noted that the TEC is depleted to the order of 30% all over the Brazilian region, from equator to beyond the EIA regions and from East to West sectors. It is also noticed that the EIA strengths at East and West sectors were suppressed after the <span class="hlt">stratospheric</span> temperature peak. However, the Brazilian West sector was found to be more disturbed compared to the East sector during this SSW event.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4823715','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4823715"><span id="translatedtitle">Dynamics of 2013 Sudden <span class="hlt">Stratospheric</span> <span class="hlt">Warming</span> event and its impact on cold weather over Eurasia: Role of planetary wave reflection</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Nath, Debashis; Chen, Wen; Zelin, Cai; Pogoreltsev, Alexander Ivanovich; Wei, Ke</p> <p>2016-01-01</p> <p>In the present study, we investigate the impact of <span class="hlt">stratospheric</span> planetary wave reflection on tropospheric weather over Central Eurasia during the 2013 Sudden <span class="hlt">Stratospheric</span> <span class="hlt">Warming</span> (SSW) event. We analyze EP fluxes and Plumb wave activity fluxes to study the two and three dimensional aspects of wave propagation, respectively. The 2013 SSW event is excited by the combined influence of wavenumber 1 (WN1) and wavenumber 2 (WN2) planetary waves, which makes the event an unusual one and seems to have significant impact on tropospheric weather regime. We observe an extraordinary development of a ridge over the Siberian Tundra and the North Pacific during first development stage (last week of December 2012) and later from the North Atlantic in the second development stage (first week of January 2013), and these waves appear to be responsible for the excitation of the WN2 pattern during the SSW. The wave packets propagated upward and were then reflected back down to central Eurasia due to strong negative wind shear in the upper <span class="hlt">stratospheric</span> polar jet, caused by the SSW event. Waves that propagated downward led to the formation of a deep trough over Eurasia and brought extreme cold weather over Kazakhstan, the Southern part of Russia and the Northwestern part of China during mid-January 2013. PMID:27051997</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20110005602','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20110005602"><span id="translatedtitle">Can the GEOS CCM Simulate the Temperature Response to <span class="hlt">Warm</span> Pool El Nino Events in the Antarctic <span class="hlt">Stratosphere</span>?</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Hurwitz, M. M.; Song, I.-S.; Oman, L. D.; Newman, P. A.; Molod, A. M.; Frith, S. M.; Nielsen, J. E.</p> <p>2010-01-01</p> <p>"<span class="hlt">Warm</span> pool" (WP) El Nino events are characterized by positive sea surface temperature (SST) anomalies in the central equatorial Pacific. During austral spring. WP El Nino events are associated with an enhancement of convective activity in the South Pacific Convergence Zone, provoking a tropospheric planetary wave response and thus increasing planetary wave driving of the Southern Hemisphere <span class="hlt">stratosphere</span>. These conditions lead to higher polar <span class="hlt">stratospheric</span> temperatures and to a weaker polar jet during austral summer, as compared with neutral ENSO years. Furthermore, this response is sensitive to the phase of the quasi-biennial oscillation (QBO): a stronger <span class="hlt">warming</span> is seen in WP El Nino events coincident with the easterly phase of the quasi-biennial oscillation (QBO) as compared with WP El Nino events coincident with a westerly or neutral QBO. The Goddard Earth Observing System (GEOS) chemistry-climate model (CCM) is used to further explore the atmospheric response to ENSO. Time-slice simulations are forced by composited SSTs from observed WP El Nino and neutral ENSO events. The modeled eddy heat flux, temperature and wind responses to WP El Nino events are compared with observations. A new gravity wave drag scheme has been implemented in the GEOS CCM, enabling the model to produce a realistic, internally generated QBO. By repeating the above time-slice simulations with this new model version, the sensitivity of the WP El Nino response to the phase of the quasi-biennial oscillation QBO is estimated.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20110005628','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20110005628"><span id="translatedtitle">Can the GEOS CCM Simulate the Temperature Response to <span class="hlt">Warm</span> Pool El Nino Events in the Antarctic <span class="hlt">Stratosphere</span>?</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Hurwitz, M. M.; Song, I.-S.; Oman, L. D.; Newman, P. A.; Molod, A. M.; Frith, S. M.; Nielsen, J. E.</p> <p>2011-01-01</p> <p>"<span class="hlt">Warm</span> pool" (WP) El Nino events are characterized by positive sea surface temperature (SST) anomalies in the central equatorial Pacific. During austral spring, WP El Nino events are associated with an enhancement of convective activity in the South Pacific Convergence Zone, provoking a tropospheric planetary wave response and thus increasing planetary wave driving of the Southern Hemisphere <span class="hlt">stratosphere</span>. These conditions lead to higher polar <span class="hlt">stratospheric</span> temperatures and to a weaker polar jet during austral summer, as compared with neutral ENSO years. Furthermore, this response is sensitive to the phase of the quasi-biennial oscillation (QBO): a stronger <span class="hlt">warming</span> is seen in WP El Nino events coincident with the easterly phase of the quasi-biennial oscillation (QBO) as compared with WP El Nino events coincident with a westerly or neutral QBO. The Goddard Earth Observing System (GEOS) chemistry-climate model (CCM) is used to further explore the atmospheric response to ENSO. Time-slice simulations are forced by composited SSTs from observed NP El Nino and neutral ENSO events. The modeled eddy heat flux, temperature and wind responses to WP El Nino events are compared with observations. A new gravity wave drag scheme has been implemented in the GEOS CCM, enabling the model to produce e realistic, internally generated QBO. By repeating the above time-slice simulations with this new model version, the sensitivity of the WP El Nino response to the phase of the quasi-biennial oscillation QBO is estimated.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009ACP.....9.4775M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009ACP.....9.4775M"><span id="translatedtitle">Satellite observations and modeling of transport in the upper troposphere through the lower mesosphere during the 2006 major <span class="hlt">stratospheric</span> sudden <span class="hlt">warming</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Manney, G. L.; Harwood, R. S.; MacKenzie, I. A.; Minschwaner, K.; Allen, D. R.; Santee, M. L.; Walker, K. A.; Hegglin, M. I.; Lambert, A.; Pumphrey, H. C.; Bernath, P. F.; Boone, C. D.; Schwartz, M. J.; Livesey, N. J.; Daffer, W. H.; Fuller, R. A.</p> <p>2009-07-01</p> <p>An unusually strong and prolonged <span class="hlt">stratospheric</span> sudden <span class="hlt">warming</span> (SSW) in January 2006 was the first major SSW for which globally distributed long-lived trace gas data are available covering the upper troposphere through the lower mesosphere. We use Aura Microwave Limb Sounder (MLS), Atmospheric Chemistry Experiment-Fourier Transform Spectrometer (ACE-FTS) data, the SLIMCAT Chemistry Transport Model (CTM), and assimilated meteorological analyses to provide a comprehensive picture of transport during this event. The upper tropospheric ridge that triggered the SSW was associated with an elevated tropopause and layering in trace gas profiles in conjunction with <span class="hlt">stratospheric</span> and tropospheric intrusions. Anomalous poleward transport (with corresponding quasi-isentropic troposphere-to-<span class="hlt">stratosphere</span> exchange at the lowest levels studied) in the region over the ridge extended well into the lower <span class="hlt">stratosphere</span>. In the middle and upper <span class="hlt">stratosphere</span>, the breakdown of the polar vortex transport barrier was seen in a signature of rapid, widespread mixing in trace gases, including CO, H2O, CH4 and N2O. The vortex broke down slightly later and more slowly in the lower than in the middle <span class="hlt">stratosphere</span>. In the middle and lower <span class="hlt">stratosphere</span>, small remnants with trace gas values characteristic of the pre-SSW vortex lingered through the weak and slow recovery of the vortex. The upper <span class="hlt">stratospheric</span> vortex quickly reformed, and, as enhanced diabatic descent set in, CO descended into this strong vortex, echoing the fall vortex development. Trace gas evolution in the SLIMCAT CTM agrees well with that in the satellite trace gas data from the upper troposphere through the middle <span class="hlt">stratosphere</span>. In the upper <span class="hlt">stratosphere</span> and lower mesosphere, the SLIMCAT simulation does not capture the strong descent of mesospheric CO and H2O values into the reformed vortex; this poor CTM performance in the upper <span class="hlt">stratosphere</span> and lower mesosphere results primarily from biases in the diabatic descent in assimilated</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20120002032&hterms=Richter+scale&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3D%2528Richter%2Bscale%2529','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20120002032&hterms=Richter+scale&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3D%2528Richter%2Bscale%2529"><span id="translatedtitle">Mesoscale Simulations of Gravity Waves During the 2008-2009 Major <span class="hlt">Stratospheric</span> Sudden <span class="hlt">Warming</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Limpasuvan, Varavut; Alexander, M. Joan; Orsolini, Yvan J.; Wu, Dong L.; Xue, Ming; Richter, Jadwiga H.; Yamashita, Chihoko</p> <p>2011-01-01</p> <p>A series of 24 h mesoscale simulations (of 10 km horizontal and 400 m vertical resolution) are performed to examine the characteristics and forcing of gravity waves (GWs) relative to planetary waves (PWs) during the 2008-2009 major <span class="hlt">stratospheric</span> sudden wam1ing (SSW). Just prior to SSW occurrence, widespread westward propagating GWs are found along the vortex's edge and associated predominantly with major topographical features and strong near-surface winds. Momentum forcing due to GWs surpasses PW forcing in the upper <span class="hlt">stratosphere</span> and tends to decelerate the polar westerly jet in excess of 30 m/s/d. With SSW onset, PWs dominate the momentum forcing, providing decelerative effects in excess of 50 m/s/d throughout the upper polar <span class="hlt">stratosphere</span>. GWs related to topography become less widespread largely due to incipient wind reversal as the vortex starts to elongate. During the SSW maturation and early recovery, the polar vortex eventually splits and both wave signatures and forcing greatly subside. Nonetheless, during SSW, westward and eastward propagating GWs are found in the polar region and may be generated in situ by flow adjustment processes in the <span class="hlt">stratosphere</span> or by secondary GW breaking. The simulated large-scale features agree well with those resolved in satellite observations and analysis products.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011JGRA..11612321W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011JGRA..11612321W"><span id="translatedtitle">First simulations with a whole atmosphere data assimilation and forecast system: The January 2009 major sudden <span class="hlt">stratospheric</span> <span class="hlt">warming</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wang, H.; Fuller-Rowell, T. J.; Akmaev, R. A.; Hu, M.; Kleist, D. T.; Iredell, M. D.</p> <p>2011-12-01</p> <p>A Whole atmosphere Data Assimilation System (WDAS) is used to simulate the January 2009 sudden <span class="hlt">stratospheric</span> <span class="hlt">warming</span> (SSW). WDAS consists of the Whole Atmosphere Model (WAM) and the 3-dimensional variational (3DVar) analysis system GSI (Grid point Statistical Interpolation), modified to be compatible with the WAM model. An incremental analysis update (IAU) scheme was implemented in the data assimilation cycle to overcome the problem of excessive damping by digital filter in WAM of the important tidal waves in the upper atmosphere. IAU updates analysis incrementally into the model, thus avoids the initialization procedure (i.e., digital filter) during the WAM forecast stage. The WDAS simulation of the January 2009 SSW shows a significant increase in TW3 (terdiurnal, westward propagating, zonal wave number 3) and a decrease in SW2 (semidiurnal, westward propagating, zonal wave number 2) wave amplitudes in the E region during the <span class="hlt">warming</span>, which can be attributed likely to the nonlinear wave-wave interactions between SW2, TW3 and DW1 (diurnal, westward propagating, zonal wave number 1). There is a delayed increase in SW2 in the E region after the <span class="hlt">warming</span>, indicating a modulation by the changing large-scale planetary waves in the loweratmosphere during the SSW. These tidal wave responses during SSW appeared to be global in scale. An extended WAM forecast initialized from WDAS analysis shows remarkably consistent tidal wave responses to SSW, indicating a potential forecasting capability of several days in advance of the effects of the large-scale tropospheric and <span class="hlt">stratospheric</span> dynamics on the thermospheric and ionospheric variability.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015ACP....15..297E','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015ACP....15..297E"><span id="translatedtitle">A global non-hydrostatic model study of a downward coupling through the tropical tropopause layer during a <span class="hlt">stratospheric</span> sudden <span class="hlt">warming</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Eguchi, N.; Kodera, K.; Nasuno, T.</p> <p>2015-01-01</p> <p>The dynamical coupling process between the <span class="hlt">stratosphere</span> and troposphere in the tropical tropopause layer (TTL) during a~<span class="hlt">stratospheric</span> sudden <span class="hlt">warming</span> (SSW) in boreal winter was investigated using simulation data from a global non-hydrostatic model (NICAM) that does not use cumulus parameterization. The model reproduced well the observed tropical tropospheric changes during the SSW, including the enhancement of convective activity following the amplification of planetary waves. Deep convective activity was enhanced in the latitude zone 20-10° S, in particular over the southwest Pacific and southwest Indian Ocean. Although the upwelling in the TTL was correlated with that in the <span class="hlt">stratosphere</span>, the temperature tendency in the TTL changed little due to a compensation by diabatic heating originating from cloud formation. This result suggests that the <span class="hlt">stratospheric</span> meridional circulation affects cloud formation in the TTL.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014ACPD...14.6803E','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014ACPD...14.6803E"><span id="translatedtitle">A global non-hydrostatic model study of a downward coupling through the tropical tropopause layer during a <span class="hlt">stratospheric</span> sudden <span class="hlt">warming</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Eguchi, N.; Kodera, K.; Nasuno, T.</p> <p>2014-03-01</p> <p>The dynamical coupling process between the <span class="hlt">stratosphere</span> and troposphere in the tropical tropopause layer (TTL) during a <span class="hlt">stratospheric</span> sudden <span class="hlt">warming</span> (SSW) in boreal winter was investigated using simulation data from a global non-hydrostatic model (NICAM) that does not use cumulus parameterization. The model reproduced well the observed tropical tropospheric changes during the SSW including the enhancement of convective activity following the amplification of planetary waves. Deep convective activity was enhanced in the latitude zone 20-10° S, in particular over the southwest Pacific and southwest Indian Ocean. Although the upwelling in the TTL was correlated with that in the <span class="hlt">stratosphere</span>, the temperature tendency in the TTL was mainly controlled by diabatic heating originating from cloud formation. This result suggests that the <span class="hlt">stratospheric</span> meridional circulation affects cloud formation in the TTL.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010cosp...38.1318K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010cosp...38.1318K"><span id="translatedtitle">Impacts of a <span class="hlt">stratospheric</span> sudden <span class="hlt">warming</span> on thermal structures in the high-latitude mesosphere, lower thermosphere, and ionosphere</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kurihara, Junichi; Oyama, Shin-Ichiro; Nozawa, Satonori; Fujii, Ryoichi; Tsutsumi, Masaki; Ogawa, Yasunobu; Tomikawa, Yoshihiro; Hall, Chris</p> <p></p> <p>We analyzed neutral winds, diffusion coefficients, and neutral temperatures observed by the Nippon/Norway Tromsø Meteor Radar (NTMR) and ion temperatures observed by the Eu-ropean Incoherent Scatter (EISCAT) UHF radar at Tromsø (69.6o N, 19.2 E), during a major <span class="hlt">stratospheric</span> sudden <span class="hlt">warming</span> (SSW) occurred in January 2009. The neutral zonal winds at 80-100 km height reversed about 10 days earlier than the zonal wind reversal in the <span class="hlt">stratosphere</span> and the neutral temperature at 90 km decreased simultaneously with the zonal wind reversal at the same altitude. We found an anticorrelation between geomagnetically quiet nighttime ion temperatures at 100 km and 120-142 km. Our results from the ground-based observations agree well with the satellite observations shown in an accompanying paper. However, significant differences from the previous studies on other SSW events indicate that impacts of a SSW on the upper atmosphere and ionosphere are highly variable with lower atmospheric conditions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014cosp...40E1520K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014cosp...40E1520K"><span id="translatedtitle">Finding of the key formation mechanisms of the ionospheric response to sudden <span class="hlt">stratospheric</span> <span class="hlt">warming</span> using GSM TIP model</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Klimenko, Vladimir; Klimenko, Maxim; Bessarab, Fedor; Korenkov, Yurij; Karpov, Ivan</p> <p></p> <p>The Sudden <span class="hlt">Stratospheric</span> <span class="hlt">Warming</span> (SSW) is a large-scale phenomenon, which response is detected in the mesosphere, thermosphere and ionosphere. SSW ionospheric effects are studied using multi-instrumental satellites and by ground-based measurements. We report a brief overview of the observational and theoretical results of the global ionospheric response and its formation mechanisms during Sudden <span class="hlt">Stratospheric</span> <span class="hlt">Warming</span>. We also present the results of our investigation of thermosphere-ionosphere response to the SSW obtained within the Global Self-consistent Model of the Thermosphere, Ionosphere, Protonosphere (GSM TIP). The SSW effects were modeled by specifying various boundary conditions at the height of 80 km in the GSM TIP model: (1) by setting the stationary perturbations s = 1 of the temperature and density at high latitudes; (2) by setting the global distribution of the neutral atmosphere parameters, calculated in the TIME-GCM and CCM SOCOL models for the conditions of the SSW 2009 event. It has been shown that the selected low boundary conditions do not allow to fully reproduce the observed variation in the ionospheric parameters during SSW 2009 event. Based on observations of the velocity of vertical plasma drift obtained by the incoherent scatter radar at Jicamarca, we introduced additional electric potential in the GSM TIP model, which allowed us to reproduce the zonal electric field (ÉB vertical plasma drift) and the observed SSW effects in the low-latitude ionosphere. Furthermore, we tried to reproduce the SSW ionospheric effects by including internal gravity waves in the high-latitude mesosphere. We discuss the model calculation results and possible reasons for model/data disagreements and give the proposals for further investigations. This work was supported by RFBR Grants №12-05-31217 and №14-05-00578.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_4");'>4</a></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li class="active"><span>6</span></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_6 --> <div id="page_7" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li class="active"><span>7</span></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="121"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19920020073&hterms=dao&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Ddao','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19920020073&hterms=dao&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Ddao"><span id="translatedtitle">Rayleigh/raman Greenland Lidar Observations of Atmospheric Temperature During a Major Arctic <span class="hlt">Stratospheric</span> <span class="hlt">Warming</span> Event</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Meriwether, John W.; Farley, Robert; Mcnutt, R.; Dao, Phan D.; Moskowitz, Warren P.</p> <p>1992-01-01</p> <p>Between Jan. 22 1991 to Feb. 5 1991, we made numerous observations of atmospheric temperature profiles between 10 and 70 km by using the combination of Rayleigh and Raman lidar systems contained in the PL Mobile Lidar Facility located at the National Science Foundation Incoherent Radar Facility of Sondrestrom in Greenland. The purpose of these measurements was to observe the dynamics of the winter Arctic <span class="hlt">stratosphere</span> and mesosphere regions during a winter period from the succession of temperature profiles obtained in our campaign observations. Various aspects of this investigation are presented.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014JGRA..119.1287M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014JGRA..119.1287M"><span id="translatedtitle">TIME-GCM study of the ionospheric equatorial vertical drift changes during the 2006 <span class="hlt">stratospheric</span> sudden <span class="hlt">warming</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Maute, A.; Hagan, M. E.; Richmond, A. D.; Roble, R. G.</p> <p>2014-02-01</p> <p>This modeling study quantifies the daytime low-latitude vertical E×B drift changes in the longitudinal wave number 1 (wn1) to wn4 during the major extended January 2006 <span class="hlt">stratospheric</span> sudden <span class="hlt">warming</span> (SSW) period as simulated by the National Center for Atmospheric Research thermosphere-ionosphere-mesosphere electrodynamics general circulation model (TIME-GCM), and attributes the drift changes to specific tides and planetary waves (PWs). The largest drift amplitude change (approximately 5 m/s) is seen in wn1 with a strong temporal correlation to the SSW. The wn1 drift is primarily caused by the semidiurnal westward propagating tide with zonal wave number 1 (SW1), and secondarily by a stationary planetary wave with zonal wave number 1 (PW1). SW1 is generated by the nonlinear interaction of PW1 and the migrating semidiurnal tide (SW2) at high latitude around 90-100 km. The simulations suggest that the E region PW1 around 100-130 km at the different latitudes has different origins: at high latitudes, the PW1 is related to the original <span class="hlt">stratospheric</span> PW1; at midlatitudes, the model indicates PW1 is due to the nonlinear interaction of SW1 and SW2 around 95-105 km; and at low latitudes, the PW1 might be caused by the nonlinear interaction between DE2 and DE3. The time evolution of the simulated wn4 in the vertical E×B drift amplitude shows no temporal correlation with the SSW. The wn4 in the low-latitude vertical drift is attributed to the diurnal eastward propagating tide with zonal wave number 3 (DE3), and the contributions from SE2, TE1, and PW4 are negligible.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012ACPD...1220033A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012ACPD...1220033A"><span id="translatedtitle">The spring 2011 final <span class="hlt">stratospheric</span> <span class="hlt">warming</span> above Eureka: anomalous dynamics and chemistry</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Adams, C.; Strong, K.; Zhao, X.; Bourassa, A. E.; Daffer, W. H.; Degenstein, D.; Drummond, J. R.; Farahani, E. E.; Fraser, A.; Lloyd, N. D.; Manney, G. L.; McLinden, C. A.; Rex, M.; Roth, C.; Strahan, S. E.; Walker, K. A.; Wohltmann, I.</p> <p>2012-08-01</p> <p>In spring 2011, the Arctic polar vortex was stronger than in any other year on record. As the polar vortex started to break up in April, ozone and NO2 columns were measured with UV-visible spectrometers above the Polar Environment Atmospheric Research Laboratory (PEARL) in Eureka, Canada (80.05° N, 86.42° W) using the differential optical absorption spectroscopy (DOAS) technique. These ground-based column measurements were complemented by Ozone Monitoring Instrument (OMI) and Optical Spectrograph and Infra-Red Imager System (OSIRIS) satellite measurements, Global Modeling Initiative (GMI) simulations, and dynamical parameters. On 8 April 2011, NO2 columns above PEARL from the DOAS, OMI, and GMI datasets were approximately twice as large as in previous years. On this day, temperatures and ozone volume mixing ratios above Eureka were high, suggesting enhanced chemical production of NO2 from NO. Additionally, GMI NOx and N2O fields suggest that downward transport along the vortex edge and horizontal transport from lower latitudes also contributed to the enhanced NO2. The anticyclone that transported lower-latitude NOx above PEARL became frozen-in and persisted in dynamical and GMI N2O fields until the end of the measurement period on 31 May 2011. Ozone isolated within this frozen-in anticyclone (FrIAC) in the middle <span class="hlt">stratosphere</span> was depleted due to reactions with the enhanced NOx. Ozone loss was calculated using the passive tracer technique, with passive ozone profiles from the Lagrangian Chemistry and Transport Model, ATLAS. At 600 K, ozone losses between 1 December 2010 and 20 May 2011 reached 4.2 parts per million by volume (ppmv) (58%) and 4.4 ppmv (61%), when calculated using GMI and OSIRIS ozone profiles, respectively. This middle-<span class="hlt">stratosphere</span> gas-phase ozone loss led to a more rapid decrease in ozone column amounts in April/May 2011 compared with previous years. Ground-based, OMI, and GMI ozone total columns within the FrIAC all decreased by more than 100 DU</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016JGRA..121.1658M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016JGRA..121.1658M"><span id="translatedtitle">Equatorial vertical drift modulation by the lunar and solar semidiurnal tides during the 2013 sudden <span class="hlt">stratospheric</span> <span class="hlt">warming</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Maute, A.; Fejer, B. G.; Forbes, J. M.; Zhang, X.; Yudin, V.</p> <p>2016-02-01</p> <p>During the 2013 <span class="hlt">stratospheric</span> sudden <span class="hlt">warming</span> (SSW) period the Jicamarca Unattended Long-term Investigations of the Ionosphere and Atmosphere (JULIA) radar at Jicarmarca, Peru, observed low-latitude vertical drift modulation with lows of 0-12 m/s daytime maximum drifts between 6-13 and 22-25 January and enhanced drifts up to 43 m/s between 15 snd 19 January. The NCAR thermosphere-ionosphere-mesosphere-electrodynamics general circulation model reproduces the prevailing vertical drift feature and is used to examine possible causes. The simulations indicate that the modulation of the vertical drift is generated by the beating of the semidiurnal solar SW2 and lunar M2 tides. During the SSW period the beating is observable since the magnitudes of lunar and solar semidiurnal tidal amplitudes are comparable. The theoretical beating frequency between SW2 and M2 is 1/(15.13 day) which may be modified due to phase changes. This study highlights the importance of the lunar tide during SSW periods and indicates that the equatorial vertical drift modulation should be observable at other longitudes as well.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013ACP....13..611A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013ACP....13..611A"><span id="translatedtitle">The spring 2011 final <span class="hlt">stratospheric</span> <span class="hlt">warming</span> above Eureka: anomalous dynamics and chemistry</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Adams, C.; Strong, K.; Zhao, X.; Bourassa, A. E.; Daffer, W. H.; Degenstein, D.; Drummond, J. R.; Farahani, E. E.; Fraser, A.; Lloyd, N. D.; Manney, G. L.; McLinden, C. A.; Rex, M.; Roth, C.; Strahan, S. E.; Walker, K. A.; Wohltmann, I.</p> <p>2013-01-01</p> <p>In spring 2011, the Arctic polar vortex was stronger than in any other year on record. As the polar vortex started to break up in April, ozone and NO2 columns were measured with UV-visible spectrometers above the Polar Environment Atmospheric Research Laboratory (PEARL) in Eureka, Canada (80.05° N, 86.42° W) using the differential optical absorption spectroscopy (DOAS) technique. These ground-based column measurements were complemented by Ozone Monitoring Instrument (OMI) and Optical Spectrograph and Infra-Red Imager System (OSIRIS) satellite measurements, Global Modeling Initiative (GMI) simulations, and meteorological quantities. On 8 April 2011, NO2 columns above PEARL from the DOAS, OMI, and GMI datasets were approximately twice as large as in previous years. On this day, temperatures and ozone volume mixing ratios above Eureka were high, suggesting enhanced chemical production of NO2 from NO. Additionally, GMI NOx (NO + NO2) and N2O fields suggest that downward transport along the vortex edge and horizontal transport from lower latitudes also contributed to the enhanced NO2. The anticyclone that transported lower-latitude NOx above PEARL became frozen-in and persisted in dynamical and GMI N2O fields until the end of the measurement period on 31 May 2011. Ozone isolated within this frozen-in anticyclone (FrIAC) in the middle <span class="hlt">stratosphere</span> was lost due to reactions with the enhanced NOx. Below the FrIAC (from the tropopause to 700 K), NOx driven ozone loss above Eureka was larger than in previous years, according to GMI monthly average ozone loss rates. Using the passive tracer technique, with passive ozone profiles from the Lagrangian Chemistry and Transport Model, ATLAS, ozone losses since 1 December 2010 were calculated at 600 K. In the air mass that was above Eureka on 20 May 2011, ozone losses reached 4.2 parts per million by volume (ppmv) (58%) and 4.4 ppmv (61%), when calculated using GMI and OSIRIS ozone profiles, respectively. This gas-phase ozone loss</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/10182802','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/10182802"><span id="translatedtitle">Indirect global <span class="hlt">warming</span> effects of ozone and <span class="hlt">stratospheric</span> water vapor induced by surface methane emission</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Wuebbles, D.J.; Grossman, A.S.; Tamaresis, J.S.; Patten, K.O. Jr.; Jain, A.; Grant, K.A.</p> <p>1994-07-01</p> <p>Methane has indirect effects on climate due to chemical interactions as well as direct radiative forcing effects as a greenhouse gas. We have calculated the indirect, time-varying tropospheric radiative forcing and GWP of O{sub 3} and <span class="hlt">stratospheric</span> H{sub 2}O due to an impulse of CH{sub 4}. This impulse, applied to the lowest layer of the atmosphere, is the increase of the atmospheric mass of CH{sub 4} resulting from a 25 percent steady state increase in the current emissions as a function of latitude. The direct CH{sub 4} radiative forcing and GWP are also calculated. The LLNL 2-D radiative-chemistry-transport model is used to evaluate the resulting changes in the O{sub 3}, H{sub 2}O and CH{sub 4} atmospheric profiles as a function of time. A correlated k-distribution radiative transfer model is used to calculate the radiative forcing at the tropopause of the globally-averaged atmosphere profiles. The O{sub 3} indirect GWPs vary from {approximately}27 after a 20 yr integration to {approximately}4 after 500 years, agreeing with the previous estimates to within about 10 percent. The H{sub 2}O indirect GWPs vary from {approximately}2 after a 20 yr integration to {approximately}0.3 after 500 years, and are in close agreement with other estimates. The CH{sub 4} GWPs vary from {approximately}53 at 20 yrs to {approximately}7 at 500 yrs. The 20 year CH{sub 4} GWP is {approximately}20% larger than previous estimates of the direct CH{sub 4} GWP due to a CH{sub 4} response time ({approximately}17 yrs) that is much longer than the overall lifetime (10 yrs). The increased CH{sub 4} response time results from changes in the OH abundances caused by the CH{sub 4} impulse. The CH{sub 4} radiative forcing results are consistent with IPCC values. Estimates are made of latitude effects in the radiative forcing calculations, and UV effects on the O{sub 3} radiative forcing calculations (10%).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFMSA21C..04M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFMSA21C..04M"><span id="translatedtitle">What can we learn from simulating <span class="hlt">Stratospheric</span> Sudden <span class="hlt">Warming</span> periods with the Thermosphere-Ionosphere-Mesosphere-Electrodynamics GCM?</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Maute, A. I.; Hagan, M. E.; Roble, R. G.; Richmond, A. D.; Yudin, V. A.; Liu, H.; Goncharenko, L. P.; Burns, A. G.; Maruyama, N.</p> <p>2013-12-01</p> <p>The ionosphere-thermosphere system is not only influenced from geospace but also by meteorological variability. Ionospheric observations of GPS TEC during the current solar cycle have shown that the meteorological variability is important during solar minimum, but also can have significant ionospheric effects during solar medium to maximum conditions. Numerical models can be used to help understand the mechanisms that couple the lower and upper atmosphere over the solar cycle. Numerical modelers invoke different methods to simulate realistic, specified events of meteorological variability, e.g. specify the lower boundary forcing, nudge the middle atmosphere, data assimilation. To study the vertical coupling, we first need to assess the numerical models and the various methods used to simulate realistic events with respect to the dynamics of the mesosphere-lower thermosphere (MLT) region, the electrodynamics, and the ionosphere. This study focuses on <span class="hlt">Stratospheric</span> Sudden <span class="hlt">Warming</span> (SSW) periods since these are associated with a strongly disturbed middle atmosphere which can have effects up to the ionosphere. We will use the NCAR Thermosphere-Ionosphere-Mesosphere-Electrodynamics General Circulation model (TIME-GCM) to examine several recent SSW periods, e.g. 2009, 2012, and 2013. The SSW period in TIME-GCM will be specified in three different ways: 1. using reanalysis data to specify the lower boundary; 2. nudging the neutral atmosphere (temperature and winds) with the Whole Atmosphere Community Climate Model (WACCM)/Goddard Earth Observing System Model, Version 5 (GEOS-5) results; 3. nudging the background atmosphere (temperature and winds) with WACCM/GEOS5 results. The different forcing methods will be evaluated for the SSW periods with respect to the dynamics of the MLT region, the low latitude vertical drift changes, and the ionospheric effects for the different SSW periods. With the help of ionospheric data at different longitudinal sectors it will be possible to</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JGRA..120.5226L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JGRA..120.5226L"><span id="translatedtitle">Thermal and dynamical perturbations in the winter polar mesosphere-lower thermosphere region associated with sudden <span class="hlt">stratospheric</span> <span class="hlt">warmings</span> under conditions of low solar activity</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lukianova, Renata; Kozlovsky, Alexander; Shalimov, Sergey; Ulich, Thomas; Lester, Mark</p> <p>2015-06-01</p> <p>The upper mesospheric neutral winds and temperatures have been derived from continuous meteor radar (MR) measurements over Sodankyla, Finland, in 2008-2014. Under conditions of low solar activity pronounced sudden mesospheric coolings linked to the major <span class="hlt">stratospheric</span> <span class="hlt">warming</span> (SSW) in 2009 and a medium SSW in 2010 are observed while there is no observed thermal signature of the major SSW in 2013 occurred during the solar maximum. Mesosphere-ionosphere anomalies observed simultaneously by the MR, the Aura satellite, and the rapid-run ionosonde during a period of major SSW include the following features. The mesospheric temperature minimum occurs 1 day ahead of the <span class="hlt">stratospheric</span> maximum, and the mesospheric cooling is almost of the same value as the <span class="hlt">stratospheric</span> <span class="hlt">warming</span> (~50 K), the former decay faster than the latter. In the course of SSW, a strong mesospheric wind shear of ~70 m/s/km occurs. The wind turns clockwise (anticlockwise) from north-eastward (south-eastward) to south-westward (north-westward) above (below) 90 km. As the mesospheric temperature reaches its minimum, the gravity waves (GW) in the ionosphere with periods of 10-60 min decay abruptly while the GWs with longer periods are not affected. The effect is explained by selective filtering and/or increased turbulence near the mesopause.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016EGUGA..1813970M&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016EGUGA..1813970M&link_type=ABSTRACT"><span id="translatedtitle">The influence of regional Arctic sea-ice decline on <span class="hlt">stratospheric</span> and tropospheric circulation</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>McKenna, Christine; Bracegirdle, Thomas; Shuckburgh, Emily; Haynes, Peter</p> <p>2016-04-01</p> <p>Arctic sea-ice extent has rapidly declined over the past few decades, and most climate models project a continuation of this trend during the 21st century in response to greenhouse gas forcing. A number of recent studies have shown that this sea-ice loss induces vertically propagating Rossby waves, which weaken the <span class="hlt">stratospheric</span> polar vortex and increase the frequency of sudden <span class="hlt">stratospheric</span> <span class="hlt">warmings</span> (<span class="hlt">SSWs</span>). <span class="hlt">SSWs</span> have been shown to increase the probability of a negative NAO in the following weeks, thereby driving anomalous weather conditions over Europe and other mid-latitude regions. In contrast, other studies have shown that Arctic sea-ice loss strengthens the polar vortex, increasing the probability of a positive NAO. Sun et al. (2015) suggest these conflicting results may be due to the region of sea-ice loss considered. They find that if only regions within the Arctic Circle are considered in sea-ice projections, the polar vortex weakens; if only regions outwith the Arctic Circle are considered, the polar vortex strengthens. This is because the anomalous Rossby waves forced in the former/latter scenario constructively/destructively interfere with climatological Rossby waves, thus enhancing/suppressing upward wave propagation. In this study, we investigate whether Sun et al.'s results are robust to a different model. We also divide the regions of sea-ice loss they considered into further sub-regions, in order to examine the regional differences in more detail. We do this by using the intermediate complexity climate model, IGCM4, which has a well resolved <span class="hlt">stratosphere</span> and does a good job of representing <span class="hlt">stratospheric</span> processes. Several simulations are run in atmosphere only mode, where one is a control experiment and the others are perturbation experiments. In the control run annually repeating historical mean surface conditions are imposed at the lower boundary, whereas in each perturbation run the model is forced by SST perturbations imposed in a specific</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFMSA41C4071F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFMSA41C4071F"><span id="translatedtitle">Ionospheric Response to the 2009 Sudden <span class="hlt">Stratospheric</span> <span class="hlt">Warming</span> over the Equatorial, Low- and Mid-Latitudes in American Sector.</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Fagundes, P. R.; Goncharenko, L. P.; de Abreu, A. J.; Gende, M.; de Jesus, R.; Pezzopane, M.; Kavutarapu, V.; Coster, A. J.; Pillat, V. G.</p> <p>2014-12-01</p> <p>The equatorial and low-latitude ionosphere/thermosphere system is predominantly disturbed by waves (MSTIDs, tides, and planetary waves), which are generated in the lower atmosphere or in-situ, as well as electric fields and TIDs produced by geomagnetic storm and UV, EUV, and X-ray solar radiation. For many years, it was thought that, during geomagnetic quiet conditions, the equatorial and low-latitude F-layer was mainly perturbed by waves that were generated not far away from the observed location or electric fields generated by the Equatorial Electroject (EEJ). On the contrary, during geomagnetic storms when the energy sources are in high latitudes the waves (TIDs) travel a very long distance from high latitude to equatorial region and electric fields can be mapped via magnetic field lines. However, in the recent times an unexpected coupling between high latitude, mid- latitude, and equatorial/low latitudes was discovered during sudden <span class="hlt">stratospheric</span> <span class="hlt">warming</span> (SSW) events. All aspects involved in this process must be explored in order to improve our knowledge about the Earth´s atmosphere. The present study investigates the consequences of vertical coupling from lower to the upper atmosphere in the equatorial and low-latitude ionosphere in Southern Hemisphere during a major SSW event, which took place during January-February 2009 in the Northern Hemisphere. Using seventeen ground-based dual-frequency GPS stations and two ionosonde stations spanning from latitude 2.8oN to 53.8oS and from longitude 36.7oW to 67.8oW over the South American sector, it has been observed that the ionosphere was significantly disturbed by the SSW event from Equator to the mid-latitudes. Using one GPS station located in mid-latitude (South America sector) it is reported for the first time that the mid-latitude in southern hemisphere (American Sector) was disturbed by the SSW event in the Northern hemisphere. The VTEC at all 17 GPS and two ionosonde stations show significant deviations</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016JASTP.146..205B&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016JASTP.146..205B&link_type=ABSTRACT"><span id="translatedtitle">Comparison of the dynamical response of low latitude middle atmosphere to the major <span class="hlt">stratospheric</span> <span class="hlt">warming</span> events in the Northern and Southern Hemispheres</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bhagavathiammal, G. J.; Sathishkumar, S.; Sridharan, S.; Gurubaran, S.</p> <p>2016-08-01</p> <p>This study presents comparison of low-latitude dynamical responses to boreal 2008/09 and austral 2002 winter Major <span class="hlt">Stratospheric</span> <span class="hlt">Warming</span> (MSW) events, as both events are of vortex split type. During these winters, planetary wave (PW) variability and changes in low-latitude circulation are examined using European Center for Medium Range Weather Forecasting (ECMWF) reanalysis (ERA)-interim data sets and mesospheric wind data acquired by the MF radars at Tirunelveli (8.7°N) and Rarotonga (22°S). Eliassen-Palm diagnostic is used to provide an evidence for the lateral PW energy propagation from high to low-latitudes during both the MSW events. The PW flux reaches much lower latitudes during the boreal event than during the austral event. The low-latitude westward winds at <span class="hlt">stratospheric</span> heights are stronger (weaker) during the boreal (austral) MSW. Weak (strong) PW wave activity at low latitude mesospheric heights during boreal (austral) MSW indicates the influence of low-latitude <span class="hlt">stratospheric</span> westward winds on the vertical propagation of PW to low-latitude mesosphere.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013JASTP..94...54N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013JASTP..94...54N"><span id="translatedtitle">Lower <span class="hlt">stratospheric</span> gravity wave activity over Gadanki (13.5°N, 79.2°E) during the <span class="hlt">stratospheric</span> sudden <span class="hlt">warming</span> of 2009: Link with potential vorticity intrusion near Indian sector</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Nath, D.; Sridharan, S.; Sathishkumar, S.; Gurubaran, S.; Chen, W.</p> <p>2013-03-01</p> <p>The relation between intrusions of <span class="hlt">stratospheric</span> air into the upper troposphere and deep convection at equator during the <span class="hlt">stratospheric</span> sudden <span class="hlt">warming</span> (SSW) event of 2009 is examined using the ERA-interim reanalysis and NOAA outgoing longwave radiation (OLR) data sets. There is an intrusion of potential vorticity (PV) equatorward and westward, when the amplitude of planetary wave of zonal wavenumber 2 at 10 hPa decreases drastically and polar <span class="hlt">stratospheric</span> temperature increases simultaneously at 60°N. As a special case, the PV intrudes as narrow tongue at longitudes near 60°E (Indian ocean sector) even to latitudes less than 20°N during the SSW, whereas PV normally intrudes near 210°E (eastern Pacific) to equatorial latitudes. Decrease in OLR is observed east of these PV intrusions. Vertical velocity is largely upward at all pressure levels. As the PV intrusion can have profound influence on tropospheric convection and the latent heat release due to equatorial convection is an important source mechanism for the generation of gravity waves, we examined gravity wave activity in the daily radiosonde observations of winds and temperature at Gadanki (13.5°N, 79.2°E). It is observed that the potential energy per unit mass, estimated from the gravity wave temperature perturbations has considerably enhanced in relation with the deep convection. The predominant direction of propagation of the gravity waves is westward prior to the SSW, as a response to the active convection over Indonesia, turns to eastward during and after the SSW, as a response to the PV intrusion induced convection over west of India.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016JGRD..121.1361A&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016JGRD..121.1361A&link_type=ABSTRACT"><span id="translatedtitle">A nudged chemistry-climate model simulation of chemical constituent distribution at northern high-latitude <span class="hlt">stratosphere</span> observed by SMILES and MLS during the 2009/2010 <span class="hlt">stratospheric</span> sudden <span class="hlt">warming</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Akiyoshi, H.; Nakamura, T.; Miyasaka, T.; Shiotani, M.; Suzuki, M.</p> <p>2016-02-01</p> <p><span class="hlt">Stratospheric</span> sudden <span class="hlt">warming</span> (SSW) is a dramatic phenomenon of the winter <span class="hlt">stratosphere</span> in which the distribution of chemical constituents, associated chemical tendency, and transport of chemical constituents differ significantly inside and outside of the polar vortex. In this study, the chemical constituent distributions in the major SSW of 2009/2010 were simulated by the Model for Interdisciplinary Research on Climate 3.2-Chemistry-Climate Model (CCM) nudged toward the European Center for Medium-Range Weather Forecasts-Interim Re-Analysis data. The results were compared with Superconducting Submillimeter-Wave Limb-Emission Sounder (SMILES) and Microwave Limb Sounder (MLS) observations. In addition, ozone tendency due to ozone transport and chemical ozone loss in the high-latitude lower <span class="hlt">stratosphere</span> before and after the SSW was analyzed for the period from 1 January 2010 to 11 February 2010. The evolution and distribution of ozone and HCl inside/outside the polar vortex associated with the vortex shift to the midlatitudes in January are quite similar between SMILES and MLS. Those of ClO are also similar, considering the difference in the local time for the measurement. Analyses of the nudged CCM run indicate that inside the polar vortex at 50 hPa, the ozone concentration increased moderately owing to partial cancelation between the large negative ozone tendency due to chemical ozone destruction and large positive ozone tendency due to horizontal ozone influx from outside of the vortex as well as downward advection. In the region of a high ozone concentration with the same area as that of the polar vortex at 50 hPa, the large increase in ozone was primarily due to a downward advection of ozone. SMILES and MLS observations, nudged CCM simulations, and ozone tendency analyses revealed a highly longitudinal dependent ozone tendency at high latitudes during the SSW.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016cosp...41E1778S&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016cosp...41E1778S&link_type=ABSTRACT"><span id="translatedtitle">Analysis of <span class="hlt">Stratospheric</span> Sudden <span class="hlt">Warming</span> (SSW) over Tropical and Sub-tropical Regions of India using Rayleigh Lidar and Satellite measurements</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sharma, Som Kumar; Chandra, Harish; Jayaraman, Achuthan; Gadhavi, Harish; Vaishnav, Rajesh</p> <p>2016-07-01</p> <p>The <span class="hlt">Stratospheric</span> Sudden <span class="hlt">Warming</span> (SSW) is one of the most spectacular phenomena in the atmosphere and has impacts on the Earth's lower, middle and upper atmospheres. Lidar is one of the best instrument to study Earth's middle atmospheric thermal structure with very temporal and vertical resolution. A Nd: YAG laser based Rayleigh Lidar is operational over Mt. Abu India (24.5 oN, 72.7 oE) since 1997.In this study, two major SSW episodes associated with vortex displacement and vortex splitting occurred in year 1998 and 1999 respectively are investigated first time over Mt. Abu using lidar observations. Analyses show that CIRA-86 and MSISE-90 model fail to capture these SSW episode, whereas ground based lidar and satellite observations from Halogen occultation experiment (HALOE) onboard upper atmospheric research satellite (UARS)are able to capture effect of SSW events. Lidar measurements are able to capture SSW <span class="hlt">warming</span> and its decay very accurately. Impact of SSW is further investigated in ECMWF Interim reanalyzed potential vorticity. Moreover, a detail study has been presented to understand the latitudinal variation of SSW <span class="hlt">warming</span> and associated mesospheric cooling over Indian region.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015EGUGA..1714787S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015EGUGA..1714787S"><span id="translatedtitle">Chemistry and dynamics of the secondary ozone layer during the sudden <span class="hlt">stratospheric</span> <span class="hlt">warming</span> in the southern hemisphere in 2002, using WACCM-SD</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Smith-Johnsen, Christine; Limpasuvan, Varavut; Yvan, Orsolini; Frode, Stordal</p> <p>2015-04-01</p> <p>A sudden <span class="hlt">stratospheric</span> <span class="hlt">warming</span> (SSW) will affect the chemistry and dynamics of the middle atmosphere, and up to the thermosphere. The major <span class="hlt">warmings</span> occur roughly every other year in the northern hemispheric winter, but has only been observed once in the southern hemisphere, during the antarctic winter of 2002. In this paper we will investigate the effects of the 2002 southern hemispheric <span class="hlt">warming</span> on the upper atmosphere, by using the National Centre for Atmospheric Research's Whole Atmosphere Community Climate Model with specified dynamics (WACCM-SD). The secondary ozone layer at around 90km altitude will be the focus, and chemical compounds such as hydrogen, oxygen, carbon monoxide and nitric oxide will be studied as well as the temperature and zonal, meridional and vertical winds, all outputs from WACCM-SD. Three reductions of the zonal mean zonal wind occurs before the final reversal from westerlies to easterlies winds defines the onset of the SSW. At about the same time, at 90 km altitude, an increase of O3 can be seen, and a decrease of NOX, O, CO, H and temperature.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/23858990','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/23858990"><span id="translatedtitle"><span class="hlt">Stratospheric</span> ozone, global <span class="hlt">warming</span>, and the principle of unintended consequences--an ongoing science and policy success story.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Andersen, Stephen O; Halberstadt, Marcel L; Borgford-Parnell, Nathan</p> <p>2013-06-01</p> <p>In 1974, Mario Molina and F. Sherwood Rowland warned that chlorofluorocarbons (CFCs) could destroy the <span class="hlt">stratospheric</span> ozone layer that protects Earth from harmful ultraviolet radiation. In the decade after scientists documented the buildup and long lifetime of CFCs in the atmosphere; found the proof that CFCs chemically decomposed in the <span class="hlt">stratosphere</span> and catalyzed the depletion of ozone; quantified the adverse effects; and motivated the public and policymakers to take action. In 1987, 24 nations plus the European Community signed the Montreal Protocol. Today, 25 years after the Montreal Protocol was agreed, every United Nations state is a party (universal ratification of 196 governments); all parties are in compliance with the stringent controls; 98% of almost 100 ozone-depleting chemicals have been phased out worldwide; and the <span class="hlt">stratospheric</span> ozone layer is on its way to recovery by 2065. A growing coalition of nations supports using the Montreal Protocol to phase down hydrofluorocarbons, which are ozone safe but potent greenhouse gases. Without rigorous science and international consensus, emissions of CFCs and related ozone-depleting substances (ODSs) could have destroyed up to two-thirds of the ozone layer by 2065, increasing the risk of causing millions of cancer cases and the potential loss of half of global agricultural production. Furthermore, because most, ODSs are also greenhouse gases, CFCs and related ODSs could have had the effect of the equivalent of 24-76 gigatons per year of carbon dioxide. This critical review describes the history of the science of <span class="hlt">stratospheric</span> ozone depletion, summarizes the evolution of control measures and compliance under the Montreal Protocol and national legislation, presents a review of six separate transformations over the last 100 years in refrigeration and air conditioning (A/C) technology, and illustrates government-industry cooperation in continually improving the environmental performance of motor vehicle A/C. PMID</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EGUGA..18..955K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EGUGA..18..955K"><span id="translatedtitle">Simulating influence of QBO phase on planetary waves during a <span class="hlt">stratospheric</span> <span class="hlt">warming</span> in a general circulation model of the middle atmosphere</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Koval, Andrey; Gavrilov, Nikolai; Pogoreltsev, Alexander; Savenkova, Elena</p> <p>2016-04-01</p> <p>One of the important factors of dynamical interactions between the lower and upper atmosphere is energy and momentum transfer by atmospheric internal gravity waves. For numerical modeling of the general circulation and thermal regime of the middle and upper atmosphere, it is important to take into account accelerations of the mean flow and heating rates produced by dissipating internal waves. The quasi-biennial oscillations (QBOs) of the zonal mean flow at lower latitudes at <span class="hlt">stratospheric</span> heights can affect the propagation conditions of planetary waves. We perform numerical simulation of global atmospheric circulation for the initial conditions corresponding to the years with westerly and easterly QBO phases. We focus on the changes in amplitudes of stationary planetary waves (SPWs) and traveling normal atmospheric modes (NAMs) in the atmosphere during SSW events for the different QBO phases. For these experiments, we use the global circulation of the middle and upper atmosphere model (MUAM). There is theory of PW waveguide describing atmospheric regions where the background wind and temperature allow the wave propagation. There were introduced the refractive index for PWs and found that strongest planetary wave propagation is in areas of large positive values of this index. Another important PW characteristic is the Eliassen-Palm flux (EP-flux). These characteristics are considered as useful tools for visualizing the PW propagation conditions. Sudden <span class="hlt">stratospheric</span> <span class="hlt">warming</span> (SSW) event has significant influence on the formation of the weather anomalous and climate changes in the troposphere. Also, SSW event may affect the dynamical and energy processes in the upper atmosphere. The major SSW events imply significant temperature rises (up to 30 - 40 K) at altitudes 30 - 50 km accompanying with corresponding decreases, or reversals, of climatological eastward zonal winds in the <span class="hlt">stratosphere</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014cosp...40E1832L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014cosp...40E1832L"><span id="translatedtitle">Study of thermospheric and ionospheric tidal responses to the 2009 <span class="hlt">stratospheric</span> sudden <span class="hlt">warming</span> by an assimilative atmosphere-ionosphere coupled TIME-GCM with FORMOSAT-3/COSMIC observations</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lin, Jia-Ting; Liu, Hanli; Liu, Jann-Yenq; Lin, Charles C. H.; Chen, Chia-Hung; Chang, Loren; Chen, Wei-Han</p> <p></p> <p>In this study, ionospheric peak densities obtained from radio occultation soundings of FORMOSAT-3/COSMIC are decomposed into their various constituent tidal components for studying the <span class="hlt">stratospheric</span> sudden <span class="hlt">warming</span> (SSW) effects on the tidal responses during the 2008/2009. The observations are further compared with the results from an atmosphere-ionosphere coupled model, TIME-GCM. The model assimilates MERRA 3D meteorological data between the lower-boundary (~30km) and 0.1h Pa (~62km) by a nudging method. The comparison shows general agreement in the major features of decrease of migrating tidal signatures (DW1, SW2 and TW3) in ionosphere around the growth phase of SSW, with phase/time shifts in the daily time of maximum around EIA and middle latitudes. Both the observation and simulation indicate a pronounced enhancement of the ionospheric SW2 signatures after the <span class="hlt">stratospheric</span> temperature increase. The model suggest that the typical morning enhancement/afternoon reduction of electron density variation is mainly caused by modification of the ionospheric migrating tidal signatures. The model shows that the thermospheric SW2 tide variation is similar to ionosphere as well as the phase shift. These phases shift of migrating tides are highly related to the present of induced secondary planetary wave 1 in the E region.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JGRA..120.7873K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JGRA..120.7873K"><span id="translatedtitle">Study of the thermospheric and ionospheric response to the 2009 sudden <span class="hlt">stratospheric</span> <span class="hlt">warming</span> using TIME-GCM and GSM TIP models: First results</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Klimenko, M. V.; Klimenko, V. V.; Bessarab, F. S.; Korenkov, Yu N.; Liu, Hanli; Goncharenko, L. P.; Tolstikov, M. V.</p> <p>2015-09-01</p> <p>This paper presents a study of mesosphere and low thermosphere influence on ionospheric disturbances during 2009 major sudden <span class="hlt">stratospheric</span> <span class="hlt">warming</span> (SSW) event. This period was characterized by extremely low solar and geomagnetic activity. The study was performed using two first principal models: thermosphere-ionosphere-mesosphere electrodynamics general circulation model (TIME-GCM) and global self-consistent model of thermosphere, ionosphere, and protonosphere (GSM TIP). The <span class="hlt">stratospheric</span> anomalies during SSW event were modeled by specifying the temperature and density perturbations at the lower boundary of the TIME-GCM (30 km altitude) according to data from European Centre for Medium-Range Weather Forecasts. Then TIME-GCM output at 80 km was used as lower boundary conditions for driving GSM TIP model runs. We compare models' results with ground-based ionospheric data at low latitudes obtained by GPS receivers in the American longitudinal sector. GSM TIP simulation predicts the occurrence of the quasi-wave vertical structure in neutral temperature disturbances at 80-200 km altitude, and the positive and negative disturbances in total electron content at low latitude during the 2009 SSW event. According to our model results the formation mechanisms of the low-latitude ionospheric response are the disturbances in the n(O)/n(N2) ratio and thermospheric wind. The change in zonal electric field is key mechanism driving the ionospheric response at low latitudes, but our model results do not completely reproduce the variability in zonal electric fields (vertical plasma drift) at low latitudes.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010GeoRL..3713806K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010GeoRL..3713806K"><span id="translatedtitle">Links between a <span class="hlt">stratospheric</span> sudden <span class="hlt">warming</span> and thermal structures and dynamics in the high-latitude mesosphere, lower thermosphere, and ionosphere</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kurihara, J.; Ogawa, Y.; Oyama, S.; Nozawa, S.; Tsutsumi, M.; Hall, C. M.; Tomikawa, Y.; Fujii, R.</p> <p>2010-07-01</p> <p>We analyzed neutral winds, ambipolar diffusion coefficients, and neutral temperatures observed by the Nippon/Norway Tromsø Meteor Radar (NTMR) and ion temperatures observed by the European Incoherent Scatter (EISCAT) UHF radar at Tromsø (69.6°N, 19.2°E), during a major <span class="hlt">stratospheric</span> sudden <span class="hlt">warming</span> (SSW) that occurred in January 2009. The zonal winds at 80-100 km height reversed approximately 10 days earlier than the zonal wind reversal in the <span class="hlt">stratosphere</span> and the neutral temperature at 90 km decreased simultaneously with the zonal wind reversal at the same altitude. We found different variations between geomagnetically quiet nighttime ion temperatures at 101-110 km and 120-142 km for about 10 days around the SSW. Our results from the ground-based observations agree well with the satellite observations shown in an accompanying paper. Thus, this study indicates that a SSW is strongly linked to thermal structure and dynamics in the high-latitude mesosphere, lower thermosphere, and ionosphere.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li class="active"><span>7</span></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_7 --> <div id="page_8" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li class="active"><span>8</span></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="141"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012JGRD..11716101T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012JGRD..11716101T"><span id="translatedtitle">Growth of planetary waves and the formation of an elevated stratopause after a major <span class="hlt">stratospheric</span> sudden <span class="hlt">warming</span> in a T213L256 GCM</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tomikawa, Yoshihiro; Sato, Kaoru; Watanabe, Shingo; Kawatani, Yoshio; Miyazaki, Kazuyuki; Takahashi, Masaaki</p> <p>2012-08-01</p> <p>Recovery processes after a major <span class="hlt">stratospheric</span> sudden <span class="hlt">warming</span> (SSW) with the formation of an elevated stratopause and a strong polar-night jet are investigated using a gravity-wave-resolving GCM. The major SSW that occurred in the GCM bears a strong resemblance to observations in January 2006 and January 2009. The recovery phase of the SSW in the GCM is divided into two stages. In the first stage during about five days just after the SSW, a large positive Eliassen-Palm (E-P) flux divergence associated with the growth of planetary waves contributes to the quick recovery of eastward wind above 2 hPa (about 42 km), which is likely due to baroclinic and/or barotropic instabilities. In the second stage over the next three weeks, a prolonged westward wind in the lower <span class="hlt">stratosphere</span> blocked upward propagation of gravity waves with westward intrinsic phase velocities. It reduces the deceleration of eastward wind in the upper mesosphere and raises the breaking height of gravity waves. Since the height of westward gravity wave forcing also rises, the polar stratopause created by the gravity-wave-driven meridional circulation is formed at an elevated height (about 75 km) compared to that before the SSW (55-65 km). In addition, the weaker westward gravity-wave forcing in the upper mesosphere drives weaker downwelling around 1 hPa and forms a cold layer. Consequently, the strong polar-night jet forms at a higher altitude than before the SSW as a result of adjustment toward the thermal wind balance. This indicates that these two stages provide eastward acceleration in different ways.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016JGRA..121.5571G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016JGRA..121.5571G"><span id="translatedtitle">An incoherent scatter radar study of the midnight temperature maximum that occurred at Arecibo during a sudden <span class="hlt">stratospheric</span> <span class="hlt">warming</span> event in January 2010</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gong, Yun; Zhou, Qihou; Zhang, Shaodong; Aponte, Nestor; Sulzer, Michael</p> <p>2016-06-01</p> <p>We present an analysis of the thermospheric midnight temperature maximum, a large increment of temperature around midnight. The analysis is based on data collected from the Arecibo incoherent scatter radar during 14-21 January 2010. The experiment overlaps with a major sudden <span class="hlt">stratospheric</span> <span class="hlt">warming</span> (SSW) event which commenced on 18 January 2010. Throughout the observation, the ion temperature exhibited moderate increase around postmidnight during 14-17 January, while it showed more intense increment during 18-21 January. In particular, on 20 January, the amplitude of the midnight temperature maximum (MTM) is 310 K, which is seldom seen at Arecibo. During the SSW, the meridional wind reverses toward the pole just before the commencement of the MTM. Then, the poleward wind and the ion temperature maximize almost at the same time. The variation of meridional wind and the MTM are consistent with the Whole Atmosphere Model (WAM) studies, which suggested that the variation is due to effects from an upward propagating terdiurnal tide. On the nights of 18-19 January, the MTM showed clear phase variation at the heights of 265, 303, and 342 km. A strong terdiurnal tide has been observed during the SSW and it is likely generated from low atmosphere and propagating upward. Our results provide direct observational evidence that the propagating upward terdiurnal tide plays an important role in causing the MTM, which supports the WAM simulations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JGRD..120.8299H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JGRD..120.8299H"><span id="translatedtitle">Impacts of <span class="hlt">stratospheric</span> ozone depletion and recovery on wave propagation in the boreal winter <span class="hlt">stratosphere</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hu, Dingzhu; Tian, Wenshou; Xie, Fei; Wang, Chunxiao; Zhang, Jiankai</p> <p>2015-08-01</p> <p>This paper uses a state-of-the-art general circulation model to study the impacts of the <span class="hlt">stratospheric</span> ozone depletion from 1980 to 2000 and the expected partial ozone recovery from 2000 to 2020 on the propagation of planetary waves in December, January, and February. In the Southern Hemisphere (SH), the <span class="hlt">stratospheric</span> ozone depletion leads to a cooler and stronger Antarctic <span class="hlt">stratosphere</span>, while the <span class="hlt">stratospheric</span> ozone recovery has the opposite effects. In the Northern Hemisphere (NH), the impacts of the <span class="hlt">stratospheric</span> ozone depletion on polar <span class="hlt">stratospheric</span> temperature are not opposite to that of the <span class="hlt">stratospheric</span> ozone recovery; i.e., the <span class="hlt">stratospheric</span> ozone depletion causes a weak cooling and the <span class="hlt">stratospheric</span> ozone recovery causes a statistically significant cooling. The <span class="hlt">stratospheric</span> ozone depletion leads to a weakening of the Arctic polar vortex, while the <span class="hlt">stratospheric</span> ozone recovery leads to a strengthening of the Arctic polar vortex. The cooling of the Arctic polar vortex is found to be dynamically induced via modulating the planetary wave activity by <span class="hlt">stratospheric</span> ozone increases. Particularly interesting is that <span class="hlt">stratospheric</span> ozone changes have opposite effects on the stationary and transient wave fluxes in the NH <span class="hlt">stratosphere</span>. The analysis of the wave refractive index and Eliassen-Palm flux in the NH indicates (1) that the wave refraction in the <span class="hlt">stratosphere</span> cannot fully explain wave flux changes in the Arctic <span class="hlt">stratosphere</span> and (2) that <span class="hlt">stratospheric</span> ozone changes can cause changes in wave propagation in the northern midlatitude troposphere which in turn affect wave fluxes in the NH <span class="hlt">stratosphere</span>. In the SH, the radiative cooling (<span class="hlt">warming</span>) caused by <span class="hlt">stratospheric</span> ozone depletion (recovery) produces a larger (smaller) meridional temperature gradient in the midlatitude upper troposphere, accompanied by larger (smaller) zonal wind vertical shear and larger (smaller) vertical gradients of buoyancy frequency. Hence, there are more (fewer) transient waves</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/5147105','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/5147105"><span id="translatedtitle"><span class="hlt">Stratospheric</span> chemistry</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Brune, W.H. )</p> <p>1991-01-01</p> <p>Advances in <span class="hlt">stratospheric</span> chemistry made by investigators in the United States from 1987 to 1990 are reviewed. Subject areas under consideration include photochemistry of the polar <span class="hlt">stratosphere</span>, photochemistry of the global <span class="hlt">stratosphere</span>, and assessments of inadvertent modification of the <span class="hlt">stratosphere</span> by anthropogenic activity. Particular attention is given to early observations and theories, gas phase chemistry, Antarctic observations, Arctic observations, odd-oxygen, odd-hydrogen, odd-nitrogen, halogens, aerosols, modeling of <span class="hlt">stratospheric</span> ozone, and reactive nitrogen effects.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFMGC43D1086K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFMGC43D1086K"><span id="translatedtitle">How Much Winter <span class="hlt">Stratospheric</span> Polar-cap <span class="hlt">Warming</span> Is Explained By Upward-propagating Planetary Waves In CMIP5 Models?: Part 1. An Indirect Approach Using A Wave Interference Index</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kim, J.; Kim, B.</p> <p>2013-12-01</p> <p>The breaking of upward-propagating planetary (typically characterized by the combination of zonal wave number 1 and 2) waves in the <span class="hlt">stratosphere</span> is regarded as one of the factors that provoke the sudden <span class="hlt">stratospheric</span> <span class="hlt">warming</span> (SSW) and the accompanying collapse of <span class="hlt">stratospheric</span> polar vortex during winter. It is also known that if the anomalous stationary wave pattern is in phase with that of the climatology during a certain period, this period is dynamically favorable for the upward propagation and amplification of planetary waves. This kind of phenomenon that amplitude of resultant wave increases by combining two or more waves in phase is called the constructive interference. Our research evaluates whether and to what degree the Coupled Model Intercomparison Project Phase 5 (CMIP5) models simulate such a relation between tropospheric wave interference and Northern polar <span class="hlt">stratosphere</span> temperature anomaly during winter. Here the 500-hPa wave interference index (WII500) is defined as the coefficient that is obtained by projecting the anomaly of wave number 1 and 2 components of 500-hPa geopotential height onto its climatology. Using monthly outputs of the CMIP5 historical runs currently available to us, we examine the lagged relationship (R-square) between the WII500 during November-December-January (NDJ) and the polar-cap temperature anomaly at 50 hPa (PCT50) during December-January-February (DJF) on an interannual timescale. By sampling uncertainty in R-squares of 33-yr samples (chosen fit with the modern reanalysis period, 1980-2012) with bootstrap resampling, we obtain the sampled medians for all models. The observed relations are then calculated using six reanalyses (ERA-40, ERA-Interim, JRA-25, MERRA, NCEP-R1, and NCEP-R2), and the 5-95% confidence interval of their observed R-square is obtained again with bootstrap resampling of all six reanalyses blended. Then we evaluate which CMIP5 model simulates the WII500-PCT50 relation within the probable range of</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22391276','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22391276"><span id="translatedtitle"><span class="hlt">Stratospheric</span> aerosol geoengineering</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Robock, Alan</p> <p>2015-03-30</p> <p>The Geoengineering Model Intercomparison Project, conducting climate model experiments with standard <span class="hlt">stratospheric</span> aerosol injection scenarios, has found that insolation reduction could keep the global average temperature constant, but global average precipitation would reduce, particularly in summer monsoon regions around the world. Temperature changes would also not be uniform; the tropics would cool, but high latitudes would <span class="hlt">warm</span>, with continuing, but reduced sea ice and ice sheet melting. Temperature extremes would still increase, but not as much as without geoengineering. If geoengineering were halted all at once, there would be rapid temperature and precipitation increases at 5–10 times the rates from gradual global <span class="hlt">warming</span>. The prospect of geoengineering working may reduce the current drive toward reducing greenhouse gas emissions, and there are concerns about commercial or military control. Because geoengineering cannot safely address climate change, global efforts to reduce greenhouse gas emissions and to adapt are crucial to address anthropogenic global <span class="hlt">warming</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=1609402','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=1609402"><span id="translatedtitle"><span class="hlt">Stratospheric</span> ozone depletion</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Rowland, F. Sherwood</p> <p>2006-01-01</p> <p>Solar ultraviolet radiation creates an ozone layer in the atmosphere which in turn completely absorbs the most energetic fraction of this radiation. This process both <span class="hlt">warms</span> the air, creating the <span class="hlt">stratosphere</span> between 15 and 50 km altitude, and protects the biological activities at the Earth's surface from this damaging radiation. In the last half-century, the chemical mechanisms operating within the ozone layer have been shown to include very efficient catalytic chain reactions involving the chemical species HO, HO2, NO, NO2, Cl and ClO. The NOX and ClOX chains involve the emission at Earth's surface of stable molecules in very low concentration (N2O, CCl2F2, CCl3F, etc.) which wander in the atmosphere for as long as a century before absorbing ultraviolet radiation and decomposing to create NO and Cl in the middle of the <span class="hlt">stratospheric</span> ozone layer. The growing emissions of synthetic chlorofluorocarbon molecules cause a significant diminution in the ozone content of the <span class="hlt">stratosphere</span>, with the result that more solar ultraviolet-B radiation (290–320 nm wavelength) reaches the surface. This ozone loss occurs in the temperate zone latitudes in all seasons, and especially drastically since the early 1980s in the south polar springtime—the ‘Antarctic ozone hole’. The chemical reactions causing this ozone depletion are primarily based on atomic Cl and ClO, the product of its reaction with ozone. The further manufacture of chlorofluorocarbons has been banned by the 1992 revisions of the 1987 Montreal Protocol of the United Nations. Atmospheric measurements have confirmed that the Protocol has been very successful in reducing further emissions of these molecules. Recovery of the <span class="hlt">stratosphere</span> to the ozone conditions of the 1950s will occur slowly over the rest of the twenty-first century because of the long lifetime of the precursor molecules. PMID:16627294</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/16627294','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/16627294"><span id="translatedtitle"><span class="hlt">Stratospheric</span> ozone depletion.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Rowland, F Sherwood</p> <p>2006-05-29</p> <p>Solar ultraviolet radiation creates an ozone layer in the atmosphere which in turn completely absorbs the most energetic fraction of this radiation. This process both <span class="hlt">warms</span> the air, creating the <span class="hlt">stratosphere</span> between 15 and 50 km altitude, and protects the biological activities at the Earth's surface from this damaging radiation. In the last half-century, the chemical mechanisms operating within the ozone layer have been shown to include very efficient catalytic chain reactions involving the chemical species HO, HO2, NO, NO2, Cl and ClO. The NOX and ClOX chains involve the emission at Earth's surface of stable molecules in very low concentration (N2O, CCl2F2, CCl3F, etc.) which wander in the atmosphere for as long as a century before absorbing ultraviolet radiation and decomposing to create NO and Cl in the middle of the <span class="hlt">stratospheric</span> ozone layer. The growing emissions of synthetic chlorofluorocarbon molecules cause a significant diminution in the ozone content of the <span class="hlt">stratosphere</span>, with the result that more solar ultraviolet-B radiation (290-320 nm wavelength) reaches the surface. This ozone loss occurs in the temperate zone latitudes in all seasons, and especially drastically since the early 1980s in the south polar springtime-the 'Antarctic ozone hole'. The chemical reactions causing this ozone depletion are primarily based on atomic Cl and ClO, the product of its reaction with ozone. The further manufacture of chlorofluorocarbons has been banned by the 1992 revisions of the 1987 Montreal Protocol of the United Nations. Atmospheric measurements have confirmed that the Protocol has been very successful in reducing further emissions of these molecules. Recovery of the <span class="hlt">stratosphere</span> to the ozone conditions of the 1950s will occur slowly over the rest of the twenty-first century because of the long lifetime of the precursor molecules. PMID:16627294</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2014AGUFMSA43C..04N&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2014AGUFMSA43C..04N&link_type=ABSTRACT"><span id="translatedtitle">The Future of the <span class="hlt">Stratosphere</span> and the Ozone Layer</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Newman, P. A.; Oman, L.; Pawson, S.; Fleming, E. L.; Li, F.; Jackman, C. H.</p> <p>2014-12-01</p> <p><span class="hlt">Stratospheric</span> ozone has been slightly depleted (2-4 % globally) by emissions of ozone depleting substances (ODSs). The landmark 1987 Montreal Protocol led to the end of most these ODS emissions, and total levels of ODSs have been declining since the late 1990s. The interim replacements for these ODSs were hydroclorofluorocarbons (HCFCs), but these HCFCs have also now been regulated. The period in which <span class="hlt">stratospheric</span> change has been dominated by CFC-induced ozone loss (the "CFC era") is now coming to an end, as a period begins when the impacts of <span class="hlt">stratospheric</span> circulation and chemistry changes induced by Greenhouse Gas increases (the "GHG era"). The <span class="hlt">stratosphere</span> GHG-era will be characterized by continued decreases of ODSs and increases of CO2, N2O, and CH4. In this talk, we will describe how these factors will modify <span class="hlt">stratospheric</span> ozone levels and the basic <span class="hlt">stratospheric</span> climatology: CO2 and CH4 increases will increase <span class="hlt">stratospheric</span> ozone, while N2O increases will decrease <span class="hlt">stratospheric</span> ozone. In particular, GHG increases and the associated <span class="hlt">warming</span> of the troposphere will modify <span class="hlt">stratospheric</span> transport and cool the upper <span class="hlt">stratosphere</span>. We will quantitatively show the contributions by various GHGs to these changes and the specifics of the chemical, dynamical, and radiative changes. Further, we will show how the <span class="hlt">stratosphere</span> evolves under future GHG projections from the various Representative Concentration Pathways, illustrating the different changes in <span class="hlt">stratospheric</span> ozone caused by the concurrent radiative, chemical and dynamical impacts of GHG changes.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/10162460','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/10162460"><span id="translatedtitle"><span class="hlt">Stratospheric</span> aircraft: Impact on the <span class="hlt">stratosphere</span>?</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Johnston, H.</p> <p>1992-02-01</p> <p>The steady-state distribution of natural <span class="hlt">stratospheric</span> ozone is primarily maintained through production by ultraviolet photolysis of molecular oxygen, destruction by a catalytic cycle involving nitrogen oxides (NO{sub x}), and relocation by air motions within the <span class="hlt">stratosphere</span>. Nitrogen oxides from the exhausts of a commercially viable fleet of supersonic transports would exceed the natural source of <span class="hlt">stratospheric</span> nitrogen oxides if the t should be equipped with 1990 technology jet engines. This model-free comparison between a vital natural global ingredient and a proposed new industrial product shows that building a large fleet of passenger <span class="hlt">stratospheric</span> aircraft poses a significant global problem. NASA and aircraft industries have recognized this problem and are studying the redesign of jet aircraft engines in order to reduce the nitrogen oxides emissions. In 1989 atmospheric models identified two other paths by which the ozone destroying effects of <span class="hlt">stratospheric</span> aircraft might be reduced or eliminated: (1) Use relatively low supersonic Mach numbers and flight altitudes. For a given rate of nitrogen oxides injection into the <span class="hlt">stratosphere</span>, the calculated reduction of total ozone is a strong function of altitude, and flight altitudes well below 20 kilometers give relatively low calculated ozone reductions. (2) Include heterogeneous chemistry in the two-dimensional model calculations. Necessary conditions for answering the question on the title above are to improve the quality of our understanding of the lower <span class="hlt">stratosphere</span> and to broaden our knowledge of hetergeneous <span class="hlt">stratospheric</span> chemistry. This article reviews recently proposed new mechanisms for heterogeneous reactions on the global <span class="hlt">stratospheric</span> sulfate aerosols.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/7279879','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/7279879"><span id="translatedtitle"><span class="hlt">Stratospheric</span> aircraft: Impact on the <span class="hlt">stratosphere</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Johnston, H.</p> <p>1992-02-01</p> <p>The steady-state distribution of natural <span class="hlt">stratospheric</span> ozone is primarily maintained through production by ultraviolet photolysis of molecular oxygen, destruction by a catalytic cycle involving nitrogen oxides (NO{sub x}), and relocation by air motions within the <span class="hlt">stratosphere</span>. Nitrogen oxides from the exhausts of a commercially viable fleet of supersonic transports would exceed the natural source of <span class="hlt">stratospheric</span> nitrogen oxides if the t should be equipped with 1990 technology jet engines. This model-free comparison between a vital natural global ingredient and a proposed new industrial product shows that building a large fleet of passenger <span class="hlt">stratospheric</span> aircraft poses a significant global problem. NASA and aircraft industries have recognized this problem and are studying the redesign of jet aircraft engines in order to reduce the nitrogen oxides emissions. In 1989 atmospheric models identified two other paths by which the ozone destroying effects of <span class="hlt">stratospheric</span> aircraft might be reduced or eliminated: (1) Use relatively low supersonic Mach numbers and flight altitudes. For a given rate of nitrogen oxides injection into the <span class="hlt">stratosphere</span>, the calculated reduction of total ozone is a strong function of altitude, and flight altitudes well below 20 kilometers give relatively low calculated ozone reductions. (2) Include heterogeneous chemistry in the two-dimensional model calculations. Necessary conditions for answering the question on the title above are to improve the quality of our understanding of the lower <span class="hlt">stratosphere</span> and to broaden our knowledge of hetergeneous <span class="hlt">stratospheric</span> chemistry. This article reviews recently proposed new mechanisms for heterogeneous reactions on the global <span class="hlt">stratospheric</span> sulfate aerosols.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://eric.ed.gov/?q=Ozone+AND+depletion&id=EJ912888','ERIC'); return false;" href="http://eric.ed.gov/?q=Ozone+AND+depletion&id=EJ912888"><span id="translatedtitle">Global <span class="hlt">Warming</span>: Lessons from Ozone Depletion</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Hobson, Art</p> <p>2010-01-01</p> <p>My teaching and textbook have always covered many physics-related social issues, including <span class="hlt">stratospheric</span> ozone depletion and global <span class="hlt">warming</span>. The ozone saga is an inspiring good-news story that's instructive for solving the similar but bigger problem of global <span class="hlt">warming</span>. Thus, as soon as students in my physics literacy course at the University of…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JASTP.136..187P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JASTP.136..187P"><span id="translatedtitle">Interannual and intraseasonal variability of <span class="hlt">stratospheric</span> dynamics and <span class="hlt">stratosphere</span>-troposphere coupling during northern winter</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Pogoreltsev, A. I.; Savenkova, E. N.; Aniskina, O. G.; Ermakova, T. S.; Chen, W.; Wei, K.</p> <p>2015-12-01</p> <p>The UK Met Office reanalysis data have been used to investigate the interannual and intraseasonal variability of the <span class="hlt">stratospheric</span> dynamics and thermal structure. The results obtained show that the maximum of interannual variability of the mean zonal flow associated with the quasi-biennial oscillation (QBO) is observed at the altitude of about 30 km. It is shown that there is a statistically significant influence of the QBO phase on the extratropical <span class="hlt">stratosphere</span>, the so-called, Holton-Tan effect. The results of data analysis show that the conditions under the easterly QBO phase are more favorable for the development of the sudden <span class="hlt">stratospheric</span> <span class="hlt">warmings</span> (SSW). The statistical analysis of 15 major SSW observed during two last decades has been performed. The obtained results demonstrate that in recent years internal processes associated with nonlinear interactions of stationary planetary waves (SPW) with the mean flow played a dominant role. It is shown that the first enhancement of the SPW1 in the upper <span class="hlt">stratosphere</span> takes place because of an amplification of nonlinear interactions between this wave and the mean flow. This enhancement is accompanied by a subsequent increase in the wave activity flux from the <span class="hlt">stratosphere</span> into the troposphere with further redistribution of wave activity in the horizontal plane. Then, an increase of the upward flux from the troposphere into the <span class="hlt">stratosphere</span> in another region occurs. The secondary enhancement of the planetary wave activity in the <span class="hlt">stratosphere</span> is accompanied by the heating of the polar region and the weakening, or even reversal of the <span class="hlt">stratospheric</span> jet. Additionally to the well-known result that meridional refraction of SPW to the polar region in <span class="hlt">stratosphere</span> is one of the preconditions of development SSW, the nonlinear wave-wave and wave-mean flow interactions can play an important role before and during SSW. It is shown that the upper <span class="hlt">stratosphere</span> can be considered as the region where SPW2 is generated during SSW.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EGUGA..18.9242G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EGUGA..18.9242G"><span id="translatedtitle"><span class="hlt">Stratospheric</span> Response to Intraseasonal Changes in Incoming Solar Radiation</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Garfinkel, Chaim; silverman, vered; harnik, nili; Erlich, caryn</p> <p>2016-04-01</p> <p>Superposed epoch analysis of meteorological reanalysis data is used to demonstrate a significant connection between intraseasonal solar variability and temperatures in the <span class="hlt">stratosphere</span>. Decreasing solar flux leads to a cooling of the tropical upper <span class="hlt">stratosphere</span> above 7hPa, while increasing solar flux leads to a <span class="hlt">warming</span> of the tropical upper <span class="hlt">stratosphere</span> above 7hPa, after a lag of approximately six to ten days. Late winter (February-March) Arctic <span class="hlt">stratospheric</span> temperatures also change in response to changing incoming solar flux in a manner consistent with that seen on the 11 year timescale: ten to thirty days after the start of decreasing solar flux, the polar cap <span class="hlt">warms</span> during the easterly phase of the Quasi-Biennal Oscillation. In contrast, cooling is present after decreasing solar flux during the westerly phase of the Quasi-Biennal Oscillation (though it is less robust than the <span class="hlt">warming</span> during the easterly phase). The estimated composite mean changes in Northern Hemisphere upper <span class="hlt">stratospheric</span> (~ 5hPa) polar temperatures exceed 8K, and are potentially a source of intraseasonal predictability for the surface. These changes in polar temperature are consistent with the changes in wave driving entering the <span class="hlt">stratosphere</span>. Garfinkel, C.I., V. Silverman, N. Harnik, C. Erlich, Y. Riz (2015), <span class="hlt">Stratospheric</span> Response to Intraseasonal Changes in Incoming Solar Radiation, J. Geophys. Res. Atmos., 120, 7648-7660. doi: 10.1002/2015JD023244.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/23698448','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/23698448"><span id="translatedtitle">Weakened <span class="hlt">stratospheric</span> quasibiennial oscillation driven by increased tropical mean upwelling.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Kawatani, Yoshio; Hamilton, Kevin</p> <p>2013-05-23</p> <p>The zonal wind in the tropical <span class="hlt">stratosphere</span> switches between prevailing easterlies and westerlies with a period of about 28 months. In the lowermost <span class="hlt">stratosphere</span>, the vertical structure of this quasibiennial oscillation (QBO) is linked to the mean upwelling, which itself is a key factor in determining <span class="hlt">stratospheric</span> composition. Evidence for changes in the QBO have until now been equivocal, raising questions as to the extent of <span class="hlt">stratospheric</span> circulation changes in a global <span class="hlt">warming</span> context. Here we report an analysis of near-equatorial radiosonde observations for 1953-2012, and reveal a long-term trend of weakening amplitude in the zonal wind QBO in the tropical lower <span class="hlt">stratosphere</span>. The trend is particularly notable at the 70-hectopascal pressure level (an altitude of about 19 kilometres), where the QBO amplitudes dropped by roughly one-third over the period. This trend is also apparent in the global <span class="hlt">warming</span> simulations of the four models in the Coupled Model Intercomparison Project Phase 5 (CMIP5) that realistically simulate the QBO. The weakening is most reasonably explained as resulting from a trend of increased mean tropical upwelling in the lower <span class="hlt">stratosphere</span>. Almost all comprehensive climate models have projected an intensifying tropical upwelling in global <span class="hlt">warming</span> scenarios, but attempts to estimate changes in the upwelling by using observational data have yielded ambiguous, inconclusive or contradictory results. Our discovery of a weakening trend in the lower-<span class="hlt">stratosphere</span> QBO amplitude provides strong support for the existence of a long-term trend of enhanced upwelling near the tropical tropopause. PMID:23698448</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016GeoRL..43.2323D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016GeoRL..43.2323D"><span id="translatedtitle">Transport of ice into the <span class="hlt">stratosphere</span> and the humidification of the <span class="hlt">stratosphere</span> over the 21st century</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Dessler, A. E.; Ye, H.; Wang, T.; Schoeberl, M. R.; Oman, L. D.; Douglass, A. R.; Butler, A. H.; Rosenlof, K. H.; Davis, S. M.; Portmann, R. W.</p> <p>2016-03-01</p> <p>Climate models predict that tropical lower <span class="hlt">stratospheric</span> humidity will increase as the climate <span class="hlt">warms</span>. We examine this trend in two state-of-the-art chemistry-climate models. Under high greenhouse gas emissions scenarios, the <span class="hlt">stratospheric</span> entry value of water vapor increases by ~1 ppmv over the 21st century in both models. We show with trajectory runs driven by model meteorological fields that the <span class="hlt">warming</span> tropical tropopause layer (TTL) explains 50-80% of this increase. The remainder is a consequence of trends in evaporation of ice convectively lofted into the TTL and lower <span class="hlt">stratosphere</span>. Our results further show that within the models we examined, ice lofting is primarily important on long time scales; on interannual time scales, TTL temperature variations explain most of the variations in lower <span class="hlt">stratospheric</span> humidity. Assessing the ability of models to realistically represent ice lofting processes should be a high priority in the modeling community.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19850061224&hterms=variance&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Dvariance','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19850061224&hterms=variance&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Dvariance"><span id="translatedtitle">The origin of temporal variance in long-lived trace constituents in the summer <span class="hlt">stratosphere</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Hess, P. G.; Holton, J. R.</p> <p>1985-01-01</p> <p>Temporal variances in the concentrations of N2O, CF2Cl2, CFCl3 and CH4 in the summer <span class="hlt">stratosphere</span> at a midlatitude location have been measured by Ehhalt and others. A simple dynamical model is used to argue that these variances are created by irreversible mixing associated with the springtime final <span class="hlt">stratospheric</span> <span class="hlt">warming</span>. Tracer perturbations generated during the <span class="hlt">warming</span> are advected passively in the zonal mean easterlies so that the tracer variance is effectively frozen into the summertime <span class="hlt">stratosphere</span>. Temperature perturbations, on the other hand, are subject to radiative dissipation; the temperature variance created during the final <span class="hlt">warming</span> relaxes quickly to an ambient value.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015APS..APRM14006Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015APS..APRM14006Z"><span id="translatedtitle">Studying <span class="hlt">Stratospheric</span> Temperature Variation with Cosmic Ray Measurements</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zhang, Xiaohang; He, Xiaochun</p> <p>2015-04-01</p> <p>The long term <span class="hlt">stratospheric</span> cooling in recent decades is believed to be equally important as surface <span class="hlt">warming</span> as evidence of influences of human activities on the climate system. Un- fortunatly, there are some discrepancies among different measurements of <span class="hlt">stratospheric</span> tem- peratures, which could be partially caused by the limitations of the measurement techniques. It has been known for decades that cosmic ray muon flux is sensitive to <span class="hlt">stratospheric</span> temperature change. Dorman proposed that this effect could be used to probe the tempera- ture variations in the stratophere. In this talk, a method for reconstructing <span class="hlt">stratospheric</span> temperature will be discussed. We verify this method by comparing the <span class="hlt">stratospheric</span> tem- perature measured by radiosonde with the ones derived from cosmic ray measurement at multiple locations around the globe.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26158244','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26158244"><span id="translatedtitle">Significant radiative impact of volcanic aerosol in the lowermost <span class="hlt">stratosphere</span>.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Andersson, Sandra M; Martinsson, Bengt G; Vernier, Jean-Paul; Friberg, Johan; Brenninkmeijer, Carl A M; Hermann, Markus; van Velthoven, Peter F J; Zahn, Andreas</p> <p>2015-01-01</p> <p>Despite their potential to slow global <span class="hlt">warming</span>, until recently, the radiative forcing associated with volcanic aerosols in the lowermost <span class="hlt">stratosphere</span> (LMS) had not been considered. Here we study volcanic aerosol changes in the <span class="hlt">stratosphere</span> using lidar measurements from the NASA CALIPSO satellite and aircraft measurements from the IAGOS-CARIBIC observatory. Between 2008 and 2012 volcanism frequently affected the Northern Hemisphere <span class="hlt">stratosphere</span> aerosol loadings, whereas the Southern Hemisphere generally had loadings close to background conditions. We show that half of the global <span class="hlt">stratospheric</span> aerosol optical depth following the Kasatochi, Sarychev and Nabro eruptions is attributable to LMS aerosol. On average, 30% of the global <span class="hlt">stratospheric</span> aerosol optical depth originated in the LMS during the period 2008-2011. On the basis of the two independent, high-resolution measurement methods, we show that the LMS makes an important contribution to the overall volcanic forcing. PMID:26158244</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4510655','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4510655"><span id="translatedtitle">Significant radiative impact of volcanic aerosol in the lowermost <span class="hlt">stratosphere</span></span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Andersson, Sandra M.; Martinsson, Bengt G.; Vernier, Jean-Paul; Friberg, Johan; Brenninkmeijer, Carl A. M.; Hermann, Markus; van Velthoven, Peter F. J.; Zahn, Andreas</p> <p>2015-01-01</p> <p>Despite their potential to slow global <span class="hlt">warming</span>, until recently, the radiative forcing associated with volcanic aerosols in the lowermost <span class="hlt">stratosphere</span> (LMS) had not been considered. Here we study volcanic aerosol changes in the <span class="hlt">stratosphere</span> using lidar measurements from the NASA CALIPSO satellite and aircraft measurements from the IAGOS-CARIBIC observatory. Between 2008 and 2012 volcanism frequently affected the Northern Hemisphere <span class="hlt">stratosphere</span> aerosol loadings, whereas the Southern Hemisphere generally had loadings close to background conditions. We show that half of the global <span class="hlt">stratospheric</span> aerosol optical depth following the Kasatochi, Sarychev and Nabro eruptions is attributable to LMS aerosol. On average, 30% of the global <span class="hlt">stratospheric</span> aerosol optical depth originated in the LMS during the period 2008–2011. On the basis of the two independent, high-resolution measurement methods, we show that the LMS makes an important contribution to the overall volcanic forcing. PMID:26158244</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li class="active"><span>8</span></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_8 --> <div id="page_9" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li class="active"><span>9</span></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="161"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20060026077&hterms=stratosphere&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Dstratosphere','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20060026077&hterms=stratosphere&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Dstratosphere"><span id="translatedtitle">Weather from the <span class="hlt">Stratosphere</span>?</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Baldwin, Mark P.; Thompson, David W. J.; Shuckburgh, Emily F.; Norton, Warwick A.; Gillett, Nathan P.</p> <p>2006-01-01</p> <p>Is the <span class="hlt">stratosphere</span>, the atmospheric layer between about 10 and 50 km, important for predicting changes in weather and climate? The traditional view is that the <span class="hlt">stratosphere</span> is a passive recipient of energy and waves from weather systems in the underlying troposphere, but recent evidence suggests otherwise. At a workshop in Whistler, British Columbia (1), scientists met to discuss how the <span class="hlt">stratosphere</span> responds to forcing from below, initiating feedback processes that in turn alter weather patterns in the troposphere. The lowest layer of the atmosphere, the troposphere, is highly dynamic and rich in water vapor, clouds, and weather. The <span class="hlt">stratosphere</span> above it is less dense and less turbulent (see the figure). Variability in the <span class="hlt">stratosphere</span> is dominated by hemispheric-scale changes in airflow on time scales of a week to several months. Occasionally, however, <span class="hlt">stratospheric</span> air flow changes dramatically within just a day or two, with large-scale jumps in temperature of 20 K or more. The troposphere influences the <span class="hlt">stratosphere</span> mainly through atmospheric waves that propagate upward. Recent evidence shows that the <span class="hlt">stratosphere</span> organizes this chaotic wave forcing from below to create long-lived changes in the <span class="hlt">stratospheric</span> circulation. These <span class="hlt">stratospheric</span> changes can feed back to affect weather and climate in the troposphere.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20010050736','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20010050736"><span id="translatedtitle">Climate and Ozone Response to Increased <span class="hlt">Stratospheric</span> Water Vapor</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Shindell, Drew T.</p> <p>2001-01-01</p> <p><span class="hlt">Stratospheric</span> water vapor abundance affects ozone, surface climate, and <span class="hlt">stratospheric</span> temperatures. From 30-50 km altitude, temperatures show global decreases of 3-6 K over recent decades. These may be a proxy for water vapor increases, as the Goddard Institute for Space Studies (GISS) climate model reproduces these trends only when <span class="hlt">stratospheric</span> water vapor is allowed to increase. Observations suggest that <span class="hlt">stratospheric</span> water vapor is indeed increasing, however, measurements are extremely limited in either spatial coverage or duration. The model results suggest that the observed changes may be part of a global, long-term trend. Furthermore, the required water vapor change is too large to be accounted for by increased production within the <span class="hlt">stratosphere</span>, suggesting that ongoing climate change may be altering tropospheric input. The calculated <span class="hlt">stratospheric</span> water vapor increase contributes an additional approximately equals 24% (approximately equals 0.2 W/m(exp 2)) to the global <span class="hlt">warming</span> from well-mixed greenhouse gases over the past two decades. Observed ozone depletion is also better reproduced when destruction due to increased water vapor is included. If the trend continues, it could increase future global <span class="hlt">warming</span> and impede <span class="hlt">stratospheric</span> ozone recovery.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016GeoRL..43.4609M&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016GeoRL..43.4609M&link_type=ABSTRACT"><span id="translatedtitle">The contribution of ozone to future <span class="hlt">stratospheric</span> temperature trends</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Maycock, A. C.</p> <p>2016-05-01</p> <p>The projected recovery of ozone from the effects of ozone depleting substances this century will modulate the <span class="hlt">stratospheric</span> cooling due to CO2, thereby affecting the detection and attribution of <span class="hlt">stratospheric</span> temperature trends. Here the impact of future ozone changes on <span class="hlt">stratospheric</span> temperatures is quantified for three representative concentration pathways (RCPs) using simulations from the Fifth Coupled Model Intercomparison Project (CMIP5). For models with interactive chemistry, ozone trends offset ~50% of the global annual mean upper <span class="hlt">stratospheric</span> cooling due to CO2 for RCP4.5 and 20% for RCP8.5 between 2006-2015 and 2090-2099. For RCP2.6, ozone trends cause a net <span class="hlt">warming</span> of the upper and lower <span class="hlt">stratosphere</span>. The misspecification of ozone trends for RCP2.6/RCP4.5 in models that used the International Global Atmospheric Chemistry (IGAC)/<span class="hlt">Stratosphere</span>-troposphere Processes and their Role in Climate (SPARC) Ozone Database causes anomalous <span class="hlt">warming</span> (cooling) of the upper (lower) <span class="hlt">stratosphere</span> compared to chemistry-climate models. The dependence of ozone chemistry on greenhouse gas concentrations should therefore be better represented in CMIP6.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20140013024','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20140013024"><span id="translatedtitle">Contrasting Effects of Central Pacific and Eastern Pacific El Nino on <span class="hlt">Stratospheric</span> Water Vapor</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Garfinkel, Chaim I.; Hurwitz, Margaret M.; Oman, Luke D.; Waugh, Darryn W.</p> <p>2013-01-01</p> <p>Targeted experiments with a comprehensive chemistry-climate model are used to demonstrate that seasonality and the location of the peak <span class="hlt">warming</span> of sea surface temperatures dictate the response of <span class="hlt">stratospheric</span> water vapor to El Nino. In spring, El Nino events in which sea surface temperature anomalies peak in the eastern Pacific lead to a <span class="hlt">warming</span> at the tropopause above the <span class="hlt">warm</span> pool region, and subsequently to more <span class="hlt">stratospheric</span> water vapor (consistent with previous work). However, in fall and in early winter, and also during El Nino events in which the sea surface temperature anomaly is found mainly in the central Pacific, the response is qualitatively different: temperature changes in the <span class="hlt">warm</span> pool region are nonuniform and less water vapor enters the <span class="hlt">stratosphere</span>. The difference in water vapor in the lower <span class="hlt">stratosphere</span> between the two variants of El Nino approaches 0.3 ppmv, while the difference between the winter and spring responses exceeds 0.5 ppmv.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008cosp...37.2963S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008cosp...37.2963S"><span id="translatedtitle"><span class="hlt">Stratospheric</span> Airships: New Opportunities</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Smith, Ira; Perry, William; West, Mark</p> <p></p> <p>Southwest Research Institute (SwRI) and Aerostar International, Inc. have been involved in developing a lightweight, expendable <span class="hlt">stratospheric</span> airship since 1997. The concept of a <span class="hlt">stratospheric</span> airship has been around almost as long as <span class="hlt">stratospheric</span> free balloons. Airships are defined as lighter-than-air vehicles with propulsion and steering systems. The basic technology that makes <span class="hlt">stratospheric</span> airships possible is rooted in the free floating <span class="hlt">stratospheric</span> super pressure balloon technology developed for NASA and the U.S. Air Force over the last 40 years. The current efforts are the next step in a spiral development program for a family of portable launch, long-endurance autonomous solar-electric, <span class="hlt">stratospheric</span> airships. These low-cost systems will be capable of lifting small to medium payloads (20-200 pounds) to near-space pressure altitudes of 50 mbs for a duration of 30 days or greater. Designed for launch from remote sites like a free balloon, these airships will not require large hangars or special facilities. The paper will include a brief history of <span class="hlt">stratospheric</span> airship development, a discussion of the flight environment, key technologies and performance trade study results for <span class="hlt">stratospheric</span> airships. An overview of the application of this technology to Earth and Space Sciences will be presented.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19920006240','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19920006240"><span id="translatedtitle">Trends in <span class="hlt">stratospheric</span> temperature</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Schoeberl, M. R.; Newman, P. A.; Rosenfield, J. E.; Angell, J.; Barnett, J.; Boville, B. A.; Chandra, S.; Fels, S.; Fleming, E.; Gelman, M.</p> <p>1989-01-01</p> <p><span class="hlt">Stratospheric</span> temperatures for long-term and recent trends and the determination of whether observed changes in upper <span class="hlt">stratospheric</span> temperatures are consistent with observed ozone changes are discussed. The long-term temperature trends were determined up to 30mb from radiosonde analysis (since 1970) and rocketsondes (since 1969 and 1973) up to the lower mesosphere, principally in the Northern Hemisphere. The more recent trends (since 1979) incorporate satellite observations. The mechanisms that can produce recent temperature trends in the <span class="hlt">stratosphere</span> are discussed. The following general effects are discussed: changes in ozone, changes in other radiatively active trace gases, changes in aerosols, changes in solar flux, and dynamical changes. Computations were made to estimate the temperature changes associated with the upper <span class="hlt">stratospheric</span> ozone changes reported by the Solar Backscatter Ultraviolet (SBUV) instrument aboard Nimbus-7 and the <span class="hlt">Stratospheric</span> Aerosol and Gas Experiment (SAGE) instruments.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFMGC11C0996J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFMGC11C0996J"><span id="translatedtitle">The impacts of Unilateral <span class="hlt">Stratospheric</span> Geoengineering</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Jones, A.; Haywood, J. M.; Bellouin, N.; Stephenson, D.</p> <p>2013-12-01</p> <p><span class="hlt">Stratospheric</span> geoengineering proposals have been suggested on the premise that the cooling impacts of volcanic eruptions could be deliberately mimicked to offset the impacts of increased greenhouse gas concentrations in the future by counterbalance global <span class="hlt">warming</span>. Here, we examine both the impacts of hemispherically asymmetric volcanoes in the observational record and the impact of prolonged deliberate injection of <span class="hlt">stratospheric</span> aerosol into either the northern or southern hemisphere <span class="hlt">stratosphere</span> or into both hemispheres equally to assess the impacts on Sahelian rainfall and agriculture (Haywood et al., 2013). While the frequency of volcanic eruptions during the past 100 years is too sparse for definitive attribution, there is a suggestion that volcanic eruptions that preferentially load the northern hemisphere are the harbinger of Sahelian drought. Simulations are then performed with the HadGEM2 couple atmospheric-ocean model to assess the impacts of these volcanic eruptions and deliberate unilateral <span class="hlt">stratospheric</span> geoengineering. Figure 1 shows the impacts of the geoengineering simulations which show that <span class="hlt">stratospheric</span> injection into the northern hemisphere induces a severe and prolonged Sahelian drought with undoubted detrimental consequences for the local population. Conversely injection into the southern hemisphere causes a significant greening of the Sahel with vegetation productivity enhanced by over 100%. On the face of it, this suggests potential advocacy of injection into the southern hemisphere: we will investigate potential other side-effects from such a strategy...... Haywood, J.M., A. Jones, N. Bellouin, and D.B. Stephenson, Asymmetric forcing from <span class="hlt">stratospheric</span> aerosols impacts Sahelian drought, Nature Climate Change, Vol 3, No 7, 660-665, doi: 10.1038/NCLIMATE1857, 2013.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19920005321','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19920005321"><span id="translatedtitle"><span class="hlt">Stratospheric</span> Data Analysis System (STRATAN)</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Rood, Richard B.; Fox-Rabinovitz, Michael; Lamich, David J.; Newman, Paul A.; Pfaendtner, James W.</p> <p>1990-01-01</p> <p>A state of the art <span class="hlt">stratospheric</span> analyses using a coupled <span class="hlt">stratosphere</span>/troposphere data assimilation system is produced. These analyses can be applied to <span class="hlt">stratospheric</span> studies of all types. Of importance to this effort is the application of the <span class="hlt">Stratospheric</span> Data Analysis System (STRATAN) to constituent transport and chemistry problems.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20040161514&hterms=NaSH&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3DNaSH','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20040161514&hterms=NaSH&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3DNaSH"><span id="translatedtitle"><span class="hlt">Stratospheric</span> Impact of Varying Sea Surface Temperatures</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Newman, Paul A.; Nash, Eric R.; Nielsen, Jon E.; Waugh, Darryn; Pawson, Steven</p> <p>2004-01-01</p> <p>The Finite-Volume General Circulation Model (FVGCM) has been run in 50 year simulations with the: 1) 1949-1999 Hadley Centre sea surface temperatures (SST), and 2) a fixed annual cycle of SSTs. In this presentation we first show that the 1949-1999 FVGCM simulation produces a very credible <span class="hlt">stratosphere</span> in comparison to an NCEP/NCAR reanalysis climatology. In particular, the northern hemisphere has numerous major and minor <span class="hlt">stratospheric</span> <span class="hlt">warming</span>, while the southern hemisphere has only a few over the 50-year simulation. During the northern hemisphere winter, temperatures are both warmer in the lower <span class="hlt">stratosphere</span> and the polar vortex is weaker than is found in the mid-winter southern hemisphere. Mean temperature differences in the lower <span class="hlt">stratosphere</span> are shown to be small (less than 2 K), and planetary wave forcing is found to be very consistent with the climatology. We then will show the differences between our varying SST simulation and the fixed SST simulation in both the dynamics and in two parameterized trace gases (ozone and methane). In general, differences are found to be small, with subtle changes in planetary wave forcing that lead to reduced temperatures in the SH and increased temperatures in the NH.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19890062622&hterms=Carl+Sagan&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3DCarl%2BSagan','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19890062622&hterms=Carl+Sagan&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3DCarl%2BSagan"><span id="translatedtitle">Triton - <span class="hlt">Stratospheric</span> molecules and organic sediments</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Thompson, W. Reid; Singh, Sushil K.; Khare, B. N.; Sagan, Carl</p> <p>1989-01-01</p> <p>Continuous-flow plasma discharge techniques show production rates of hydrocarbons and nitriles in N2 + CH4 atmospheres appropriate to the <span class="hlt">stratosphere</span> of Titan, and indicate that a simple eddy diffusion model together with the observed electron flux quantitatively matches the Voyager IRIS observations for all the hydrocarbons, except for the simplest ones. Charged particle chemistry is very important in Triton's <span class="hlt">stratosphere</span>. In the more CH4-rich case of Titan, many hydrocarbons and nitriles are produced in high yield. If N2 is present, the CH4 fraction is low, but hydrocarbons and nitriles are produced in fair yield, abundances of HCN and C2H2 in Triton's <span class="hlt">stratosphere</span> exceed 10 to the 19th molecules/sq cm per sec, and NCCN, C3H4, and other species are predicted to be present. These molecules may be detected by IRIS if the <span class="hlt">stratosphere</span> is as <span class="hlt">warm</span> as expected. Both organic haze and condensed gases will provide a substantial UV and visible opacity in Triton's atmosphere.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19850012148','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19850012148"><span id="translatedtitle">Abnormal Circulation Changes in the Winter <span class="hlt">Stratosphere</span>, Detected Through Variations of D Region Ionospheric Absorption</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Delamorena, B. A.</p> <p>1984-01-01</p> <p>A method to detect <span class="hlt">stratospheric</span> <span class="hlt">warmings</span> using ionospheric absorption records obtained by an Absorption Meter (method A3) is introduced. The activity of the <span class="hlt">stratospheric</span> circulation and the D region ionospheric absorption as well as other atmospheric parameters during the winter anomaly experience an abnormal variation. A simultaneity was found in the beginning of abnormal variation in the mentioned parameters, using the absorption records for detecting the initiation of the <span class="hlt">stratospheric</span> <span class="hlt">warming</span>. Results of this scientific experience of forecasting in the El Arenosillo Range, are presented.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryId=47358&keyword=WARMING+AND+EARTH&actType=&TIMSType=+&TIMSSubTypeID=&DEID=&epaNumber=&ntisID=&archiveStatus=Both&ombCat=Any&dateBeginCreated=&dateEndCreated=&dateBeginPublishedPresented=&dateEndPublishedPresented=&dateBeginUpdated=&dateEndUpdated=&dateBeginCompleted=&dateEndCompleted=&personID=&role=Any&journalID=&publisherID=&sortBy=revisionDate&count=50&CFID=75968783&CFTOKEN=90720403','EPA-EIMS'); return false;" href="http://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryId=47358&keyword=WARMING+AND+EARTH&actType=&TIMSType=+&TIMSSubTypeID=&DEID=&epaNumber=&ntisID=&archiveStatus=Both&ombCat=Any&dateBeginCreated=&dateEndCreated=&dateBeginPublishedPresented=&dateEndPublishedPresented=&dateBeginUpdated=&dateEndUpdated=&dateBeginCompleted=&dateEndCompleted=&personID=&role=Any&journalID=&publisherID=&sortBy=revisionDate&count=50&CFID=75968783&CFTOKEN=90720403"><span id="translatedtitle">LINKAGE BETWEEN CLIMATE CHANGE AND <span class="hlt">STRATOSPHERIC</span> OZONE DEPLETION</span></a></p> <p><a target="_blank" href="http://oaspub.epa.gov/eims/query.page">EPA Science Inventory</a></p> <p></p> <p></p> <p>Two primary areas link the issue of <span class="hlt">stratospheric</span> ozone depletion to global climate change: atmospheric processes and ecological processes. tmospheric processes establish a linkage through the dual roles of certain trace gases in promoting global <span class="hlt">warming</span> and in depleting the ozon...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012PhDT.......187A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012PhDT.......187A"><span id="translatedtitle">Pathways for Communicating the Effects of <span class="hlt">Stratospheric</span> Ozone to Northern Hemisphere <span class="hlt">Stratospheric</span> Climate</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Albers, John Robert</p> <p></p> <p> the upper <span class="hlt">stratosphere</span>, where damping due to photochemically accelerated cooling dominates, causing a large reduction in planetary wave drag and thus a colder polar vortex. Task two examines the role of ozone in communicating secular and episodic changes in lower <span class="hlt">stratospheric</span> ozone to affect the upper <span class="hlt">stratosphere</span> and lower mesosphere. It is found that while the radiative effects of the ozone loss are confined to the ozone loss region (below ˜30 km in height), the ozone-dynamical feedbacks amplify the response throughout the <span class="hlt">stratosphere</span> and lower mesosphere. In particular, ozone-dynamical feedbacks cause decreased zonal-mean winds and increased residual downwelling in the upper <span class="hlt">stratosphere</span>. The final task utilizes an atmospheric general circulation model. It is found that ZAO profoundly changes the morphology of the NH planetary waveguide (PWG). ZAO causes the PWG to contract meridionally and expand vertically, with a significant increase in vertical wave propagation. Consequently, there is a significant increase in the upward flux of wave activity from the troposphere and lower <span class="hlt">stratosphere</span> into the interior of the <span class="hlt">stratosphere</span> and lower mesosphere. The ZAO-induced changes in the PWG increase the Eliassen-Palm flux divergence, causing a warmer and weaker <span class="hlt">stratospheric</span> polar vortex. The implications for accurately modeling wave-driven phenomena in the middle atmosphere, including sudden <span class="hlt">stratospheric</span> <span class="hlt">warmings</span>, 11-year solar cycle-modulated wave activity, and the Brewer-Dobson circulation is examined in light of the ability of ZAO to alter the flux of planetary wave activity into the polar vortex.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3831493','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3831493"><span id="translatedtitle"><span class="hlt">Stratospheric</span> water vapor feedback</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Dessler, A. E.; Schoeberl, M. R.; Wang, T.; Davis, S. M.; Rosenlof, K. H.</p> <p>2013-01-01</p> <p>We show here that <span class="hlt">stratospheric</span> water vapor variations play an important role in the evolution of our climate. This comes from analysis of observations showing that <span class="hlt">stratospheric</span> water vapor increases with tropospheric temperature, implying the existence of a <span class="hlt">stratospheric</span> water vapor feedback. We estimate the strength of this feedback in a chemistry–climate model to be +0.3 W/(m2⋅K), which would be a significant contributor to the overall climate sensitivity. One-third of this feedback comes from increases in water vapor entering the <span class="hlt">stratosphere</span> through the tropical tropopause layer, with the rest coming from increases in water vapor entering through the extratropical tropopause. PMID:24082126</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/24082126','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/24082126"><span id="translatedtitle"><span class="hlt">Stratospheric</span> water vapor feedback.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Dessler, A E; Schoeberl, M R; Wang, T; Davis, S M; Rosenlof, K H</p> <p>2013-11-01</p> <p>We show here that <span class="hlt">stratospheric</span> water vapor variations play an important role in the evolution of our climate. This comes from analysis of observations showing that <span class="hlt">stratospheric</span> water vapor increases with tropospheric temperature, implying the existence of a <span class="hlt">stratospheric</span> water vapor feedback. We estimate the strength of this feedback in a chemistry-climate model to be +0.3 W/(m(2)⋅K), which would be a significant contributor to the overall climate sensitivity. One-third of this feedback comes from increases in water vapor entering the <span class="hlt">stratosphere</span> through the tropical tropopause layer, with the rest coming from increases in water vapor entering through the extratropical tropopause. PMID:24082126</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1994AdSpR..14...41T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1994AdSpR..14...41T"><span id="translatedtitle"><span class="hlt">Stratospheric</span> and mesospheric observations with ISAMS</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Taylor, F. W.; Ballard, J.; Dudhia, A.; Goss-Custard, M.; Kerridge, B. J.; Lambert, A.; López-Valverde, M.; Rodgers, C. D.; Remedios, J. J.</p> <p>1994-09-01</p> <p>The scientific objectives of the Improved <span class="hlt">Stratospheric</span> and Mesospheric Sounder (ISAMS) experiment involve the measurement of global temperature and composition profiles from an instrument on the Upper Atmosphere Research Satellite (UARS). This paper discusses these objectives in the light of the data acquired during the first ten months of the mission. Interesting interim results include detailed observations of a <span class="hlt">stratospheric</span> sudden <span class="hlt">warming</span> and a nitrogen dioxide (NO2) ``Noxon cliff'', enhanced thermospheric nitric oxide (NO) production during a solar flare, strongly increased concentrations of carbon monoxide (CO) over the winter poles, non-LTE behaviour of mesospheric water vapour (H2O), and unexpected transport properties of volcanic aerosol, and the long-lived tracers methane (CH4) and nitrous oxide (N2O).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015EGUGA..17.1112B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015EGUGA..17.1112B"><span id="translatedtitle">Influence of <span class="hlt">Stratospheric</span> Ozone Distribution on Tropospheric Circulation Patterns</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Barodka, Siarhei; Krasouski, Aliaksandr; Mitskevich, Yaroslav; Shalamyansky, Arkady</p> <p>2015-04-01</p> <p>In the present study we investigate the cause-and-effect relationship between the <span class="hlt">stratospheric</span> ozone distribution and tropospheric circulation, focusing our attention mainly on the possible "top-down" side of this interaction: the impact of the <span class="hlt">stratosphere</span> on tropospheric circulation patterns and the associated weather and climate conditions. Proceeding from analysis of several decades of observational data performed at the A.I. Voeikov Main Geophysical Observatory, which suggests a clear relation between the <span class="hlt">stratospheric</span> ozone distribution, temperature field of the lower <span class="hlt">stratosphere</span> and air-masses boundaries in the upper troposphere, we combine atmospheric reanalyzes and ground-based observations with numerical simulations to identify features of the general circulation that can be traced back to anomalies in the <span class="hlt">stratospheric</span> ozone field. Specifically, we analyze the time evolution of instantaneous position of the stationary upper-level atmospheric fronts, defining the boundaries of global tropospheric air masses associated with basic cells of general circulation. We assume that <span class="hlt">stratospheric</span> heating in ozone-related processes can exert its influence on the location of stationary fronts and characteristics of general circulation cells by displacing the tropopause, which itself is defined by a dynamical equilibrium between tropospheric vertical convection and <span class="hlt">stratospheric</span> radiative heating. As an example, we consider the Spring season of 2013. Unusually high total ozone column (TOC) values observed in Northern Hemisphere (NH) at the beginning of 2013 induced low tropopause level in the Atlantic region and southward displacement of the polar front, leading to an anomalously cold Spring in Europe. Furthermore, we study manifestations of this mechanism in the aftermath of sudden <span class="hlt">stratospheric</span> <span class="hlt">warming</span> (SSW) events. In particular, the November 2013 SSW over Eastern Siberia, which is characterized by abrupt <span class="hlt">stratospheric</span> temperatures change in the course of one day</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AtmRe.164..358I','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AtmRe.164..358I"><span id="translatedtitle">Characteristics of cirrus clouds in the tropical lower <span class="hlt">stratosphere</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Iwasaki, Suginori; Luo, Zhengzhao Johnny; Kubota, Hisayuki; Shibata, Takashi; Okamoto, Hajime; Ishimoto, Hiroshi</p> <p>2015-10-01</p> <p>A unique type of cloud in the tropical lower <span class="hlt">stratosphere</span>, which we call "<span class="hlt">stratospheric</span> cirrus", is described in this study. <span class="hlt">Stratospheric</span> cirrus clouds are generally detached from overshooting deep convection and are much smaller than subvisual cirrus often observed near the tropical tropopause. We analyzed two cases of <span class="hlt">stratospheric</span> cirrus in the tropical and subtropical lower <span class="hlt">stratosphere</span> captured by the space-borne lidar, Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP). Both cases occurred 2-3 hours after the most active phase of the nearby convective cloud clusters. Case 1 has a double-layer structure above the cold point height (CPH); the CPH and two cloud top heights are, respectively, 17.8, 18.9, and 19.9 km. Case 2 has a single cloud layer where CPH and the cloud top height are, respectively, 16.5 and 18.7 km. The mode radius and ice water content of the <span class="hlt">stratospheric</span> cirrus clouds are estimated to be 4-10 μm and 0.2-0.8 mg/m3 based on the radar-lidar method and consideration of the cloud particle terminal velocity. Comparisons with previous numerical model simulation studies suggest that the double-layer <span class="hlt">stratospheric</span> cirrus clouds are likely from an overshooting plume, pushed up into the <span class="hlt">stratosphere</span> in an overshoot when <span class="hlt">warm</span> <span class="hlt">stratospheric</span> air is inhomogeneously mixed with cold overshooting air. The single-layer <span class="hlt">stratospheric</span> cirrus cloud is associated with some non-negligible wind shear, so it could be a jumping cirrus cloud, although we cannot rule out the possibility that it came from an overshooting plume because of the similarity in cloud characteristics and morphology between the two cases. Guided by the case studies, an automatic algorithm was developed to select <span class="hlt">stratospheric</span> cirrus clouds for global survey and statistical analysis. A total of four years of CALIPSO and space-borne cloud radar (CloudSat) data were analyzed. Statistical analysis suggests that <span class="hlt">stratospheric</span> cirrus clouds occur on the order of 3.0 × 103 times a year</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010EGUGA..12.5779H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010EGUGA..12.5779H"><span id="translatedtitle"><span class="hlt">Stratospheric</span> changes caused by geoengineering aerosols</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Heckendorn, P.; Peter, T.; Weisenstein, D.; Luo, B. P.; Rozanov, E.; Fueglistaler, S.; Thomason, L. W.</p> <p>2010-05-01</p> <p>Anthropogenic greenhouse gas emissions are <span class="hlt">warming</span> the global climate at an unprecedented rate. Significant emission reductions will be required soon to avoid a rapid temperature rise. One of the most prominent geoengineering ideas to counteract global <span class="hlt">warming</span> is the increase of Earth's albedo by artificially enhancing <span class="hlt">stratospheric</span> sulphate aerosols. This idea is based on the observed increase of atmospheric optical thickness after volcanic eruptions. The most straightforward method, from a technical point of view, is to inject sulphur in the tropical <span class="hlt">stratosphere</span>. We use a 3D chemistry climate model, fed by aerosol size distributions from a zonal mean aerosol model, to simulate continuous injection of 1-10 Mt/a sulphur in form of SO2 into the lower tropical <span class="hlt">stratosphere</span>. The volcanic and geoengineering forcings differ in terms of their radiative, chemical and dynamical impact on climate, mainly because the geoengineering forcing has to be continuously applied over a long period of time, whereas volcanic eruptions are single events, leading to a non-linear relationship between annual sulphur input and <span class="hlt">stratospheric</span> sulphur burden. The reason is the continuous supply of sulphuric acid and hence freshly formed small aerosol particles, which enhance the formation of large aerosol particles by coagulation and, to a lesser extent, also by condensation. This shows the importance of investigating carefully the microphysics of the sulphate aerosols. The growth of the particles is sensitive to the injection region and the sulphur loading per injection time. The consequences of the formation of large particles lead to notable disadvantages. Larger particles are less efficient in cooling than small particles with the same mass. Furthermore, a large fraction of the emitted sulphur is lost rapidly by gravitational settling and subsequent tropospheric washout. Hence, larger sulphur amounts are needed to achieve a targeted cooling. Some particles are trapped in the tropopause</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2011PhDT.......202K&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2011PhDT.......202K&link_type=ABSTRACT"><span id="translatedtitle"><span class="hlt">Stratospheric</span> geoengineering with black carbon aerosols</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kravitz, Benjamin S.</p> <p></p> <p>I use a general circulation model of Earth's climate to simulate <span class="hlt">stratospheric</span> geoengineering with black carbon aerosols, varying the altitude of injection, initial particle size, and whether the deposited black carbon modifies ground albedo. 1 Tg of black carbon aerosols injected into the <span class="hlt">stratosphere</span> each year will cause significant enough surface cooling to negate anthropogenic <span class="hlt">warming</span> if the aerosols are small (r=0.03 mum) or if the aerosols are injected into the middle <span class="hlt">stratosphere</span>, although using small aerosols causes large regional cooling effects that would be catastrophic to agriculture. The aerosols cause significant <span class="hlt">stratospheric</span> heating, resulting in <span class="hlt">stratospheric</span> ozone destruction and circulation changes, most notably an increase in the Northern Hemisphere polar jet, which forms an Arctic ozone hole and forces a positive mode of the Arctic Oscillation. The hydrologic cycle is perturbed, specifically the summer monsoon system of India, Africa, and East Asia, resulting in monsoon precipitation collapse. Global primary productivity is decreased by 35.5% for the small particle case. Surface cooling causes some sea ice regrowth, but not at statistically significant levels. All of these climate impacts are exacerbated for small particle geoengineering, with high altitude geoengineering with the default particle size (r=0.08 mum) causing a reasonable amount of cooling, and large particle (r=0.15 mum) geoengineering or particle injection into the lower <span class="hlt">stratosphere</span> causing few of these effects. The modification of ground albedo by the soot particles slightly perturbs the radiative budget but does not cause any distinguishable climate effects. The cheapest means we investigated for placing 1 Tg of black carbon aerosols into the <span class="hlt">stratosphere</span> by diesel fuel combustion would cost 1.4 trillion initially and 541 billion annual, or 2.0% and 0.8% of GDP, respectively. The additional carbon dioxide released from combusting diesel to produce these aerosols is about 1</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li class="active"><span>9</span></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_9 --> <div id="page_10" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li class="active"><span>10</span></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="181"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20150011025','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20150011025"><span id="translatedtitle">Disentangling the Roles of Various Forcing Mechanisms on <span class="hlt">Stratospheric</span> Temperature Changes Since 1979 with the NASA GEOSCCM</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Aquila, Valentina; Swartz, W.; Colarco, P.; Pawson, S.; Polvani, L.; Stolarski, R.; Waugh, D.</p> <p>2015-01-01</p> <p>Observations show that the cooling of global <span class="hlt">stratospheric</span> temperatures from 1979 to 2015 took place in two major steps coincident with the 1982 El Chichon and 1991 Mount Pinatubo eruptions. In order to attribute the features of the global <span class="hlt">stratospheric</span> temperature time series to the main forcing agents, we performed a set of simulations with the NASA Goddard Earth Observing System Chemistry Climate Model. Our results show that the characteristic step-like behavior is to be attributed to the effects of the solar cycle, except for the post-1995 flattening of the lower <span class="hlt">stratospheric</span> temperatures, where the decrease in ozone depleting substances due to the Montreal Protocol slowed ozone depletion and therefore also the cooling of the <span class="hlt">stratosphere</span>. Volcanic eruptions also caused a significant <span class="hlt">warming</span> of the <span class="hlt">stratosphere</span> after 1995. The observed general cooling is mainly caused by increasing ozone depleting substances in the lower <span class="hlt">stratosphere</span>, and greenhouse gases in the middle and upper <span class="hlt">stratosphere</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19810028856&hterms=variance&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3Dvariance','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19810028856&hterms=variance&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3Dvariance"><span id="translatedtitle">Seasonal variation of radiance variances from satellite observations Implication of seasonal variation of available potential energy in the <span class="hlt">stratosphere</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Chen, T.-C.; Stanford, J. L.</p> <p>1980-01-01</p> <p>Nimbus 5 satellite radiances for the period 1973-74 are used to examine the seasonal variation of available potential energy in the <span class="hlt">stratosphere</span> in order to provide a further observational basis for a long-term numerical simulation of <span class="hlt">stratospheric</span> circulation. The maximum value of <span class="hlt">stratospheric</span> zonal available potential energy, A(Z), in the upper and middle <span class="hlt">stratosphere</span> shows pronounced variations between winter and summer, while little variation occurs in the lower <span class="hlt">stratospheric</span> A(Z). The aperiodic occurrence of sudden <span class="hlt">warmings</span> complicates the seasonal variation of A(Z) and A(E) (eddy available potential energy) in the <span class="hlt">stratosphere</span>, making the energetics irregular. Time-Fourier analysis reveals that the primary variation of A(Z) and A(E) in the <span class="hlt">stratosphere</span> is annual and semiannual, respectively.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007ACPD....7.6557K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007ACPD....7.6557K"><span id="translatedtitle">Observation of Polar <span class="hlt">Stratospheric</span> Clouds down to the Mediterranean coast</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Keckhut, P.; David, Ch.; Marchand, M.; Bekki, S.; Jumelet, J.; Hauchecorne, A.</p> <p>2007-05-01</p> <p>A Polar <span class="hlt">Stratospheric</span> Cloud (PSC) was detected for the first time in January 2006 over Southern Europe after 25 years of systematic lidar observations. This cloud was observed while the polar vortex was highly distorted during the initial phase of a major <span class="hlt">stratospheric</span> <span class="hlt">warming</span>. Very cold <span class="hlt">stratospheric</span> temperatures (<190 K) centred over the Northern-Western Europe were reported, extending down to the South of France where lidar observations were performed. CTM (Chemical Transport Model) investigations show that this event led to a significant direct ozone destruction (35 ppb/day), within and outside the vortex as chlorine activated air masses were moved to sunlight regions allowing ozone destruction. If such exceptional events of mid-latitudes PSCs were to become frequent in the future, they should not compromise the ozone recovery because their effect appears to be limited temporally and spatially. More importantly, these events might tend to be associated with the initial phase of a <span class="hlt">stratospheric</span> <span class="hlt">warming</span> that results into a weakening and <span class="hlt">warming</span> of the polar vortex and hence into a reduced probability occurrence of PSC temperatures during the rest of the winter.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007ACP.....7.5275K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007ACP.....7.5275K"><span id="translatedtitle">Observation of Polar <span class="hlt">Stratospheric</span> Clouds down to the Mediterranean coast</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Keckhut, P.; David, Ch.; Marchand, M.; Bekki, S.; Jumelet, J.; Hauchecorne, A.; Höpfner, M.</p> <p>2007-10-01</p> <p>A Polar <span class="hlt">Stratospheric</span> Cloud (PSC) was detected for the first time in January 2006 over Southern Europe after 25 years of systematic lidar observations. This cloud was observed while the polar vortex was highly distorted during the initial phase of a major <span class="hlt">stratospheric</span> <span class="hlt">warming</span>. Very cold <span class="hlt">stratospheric</span> temperatures (<190 K) centred over the Northern-Western Europe were reported, extending down to the South of France where lidar observations were performed. CTM (Chemical Transport Model) investigations show that this event led to a significant direct ozone destruction (35 ppb/day), within and outside the vortex as chlorine activated air masses were moved to sunlight regions allowing ozone destruction. If such exceptional events of mid-latitudes PSCs were to become frequent in the future, they should not compromise the ozone recovery because their effect appears to be limited temporally and spatially. More importantly, these events might tend to be associated with the initial phase of a <span class="hlt">stratospheric</span> <span class="hlt">warming</span> that results into a weakening and <span class="hlt">warming</span> of the polar vortex and hence into a reduced probability occurrence of PSC temperatures during the rest of the winter.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20080030230&hterms=stratosphere&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Dstratosphere','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20080030230&hterms=stratosphere&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Dstratosphere"><span id="translatedtitle">Analysis of the Interactions of Planetary Waves with the Mean Flow of the <span class="hlt">Stratosphere</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Newman, Paul A.</p> <p>2007-01-01</p> <p>During the winter period, large scale waves (planetary waves) are observed to propagate from the troposphere into the <span class="hlt">stratosphere</span>. Such wave events have been recognized since the 1 950s. The very largest wave events result in major <span class="hlt">stratospheric</span> <span class="hlt">warmings</span>. These large scale wave events have typical durations of a few days to 2 weeks. The wave events deposit easterly momentum in the <span class="hlt">stratosphere</span>, decelerating the polar night jet and <span class="hlt">warming</span> the polar region. In this presentation we show the typical characteristics of these events via a compositing analysis. We will show the typical periods and scales of motion and the associated decelerations and <span class="hlt">warmings</span>. We will illustrate some of the differences between major and minor <span class="hlt">warming</span> wave events. We will further illustrate the feedback by the mean flow on subsequent wave events.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2012cosp...39.1850S&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2012cosp...39.1850S&link_type=ABSTRACT"><span id="translatedtitle"><span class="hlt">Stratospheric</span> Airship Design Sensitivity</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Smith, Ira Steve; Fortenberry, Michael; Noll, . James; Perry, William</p> <p>2012-07-01</p> <p>The concept of a <span class="hlt">stratospheric</span> or high altitude powered platform has been around almost as long as <span class="hlt">stratospheric</span> free balloons. Airships are defined as Lighter-Than-Air (LTA) vehicles with propulsion and steering systems. Over the past five (5) years there has been an increased interest by the U. S. Department of Defense as well as commercial enterprises in airships at all altitudes. One of these interests is in the area of <span class="hlt">stratospheric</span> airships. Whereas DoD is primarily interested in things that look down, such platforms offer a platform for science applications, both downward and outward looking. Designing airships to operate in the <span class="hlt">stratosphere</span> is very challenging due to the extreme high altitude environment. It is significantly different than low altitude airship designs such as observed in the familiar advertising or tourism airships or blimps. The <span class="hlt">stratospheric</span> airship design is very dependent on the specific application and the particular requirements levied on the vehicle with mass and power limits. The design is a complex iterative process and is sensitive to many factors. In an effort to identify the key factors that have the greatest impacts on the design, a parametric analysis of a simplified airship design has been performed. The results of these studies will be presented.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20020009749','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20020009749"><span id="translatedtitle">Human Health Effects of Ozone Depletion From <span class="hlt">Stratospheric</span> Aircraft</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Wey, Chowen (Technical Monitor)</p> <p>2001-01-01</p> <p>This report presents EPA's initial response to NASA's request to advise on potential environmental policy issues associated with the future development of supersonic flight technologies. Consistent with the scope of the study to which NASA and EPA agreed, EPA has evaluated only the environmental concerns related to the <span class="hlt">stratospheric</span> ozone impacts of a hypothetical HSCT fleet, although recent research indicates that a fleet of HSCT is predicted to contribute to climate <span class="hlt">warming</span> as well. This report also briefly describes the international and domestic institutional frameworks established to address <span class="hlt">stratospheric</span> ozone depletion, as well as those established to control pollution from aircraft engine exhaust emissions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19880029795&hterms=Ozone+layer&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3D%2528Ozone%2Blayer%2529','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19880029795&hterms=Ozone+layer&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3D%2528Ozone%2Blayer%2529"><span id="translatedtitle">Ozone and the <span class="hlt">stratosphere</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Shimazaki, Tatsuo</p> <p>1987-01-01</p> <p>It is shown that the <span class="hlt">stratospheric</span> ozone is effective in absorbing almost all radiation below 300 nm at heights below 300 km. The distribution of global ozone in the troposphere and the lower <span class="hlt">stratosphere</span>, and the latitudinal variations of the total ozone column over four seasons are considered. The theory of the ozone layer production is discussed together with catalytic reactions for ozone loss and the mechanisms of ozone transport. Special attention is given to the anthropogenic perturbations, such as SST exhaust gases and freon gas from aerosol cans and refrigerators, that may cause an extensive destruction of the <span class="hlt">stratospheric</span> ozone layer and thus have a profound impact on the world climate and on life.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009EGUGA..1113073K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009EGUGA..1113073K"><span id="translatedtitle"><span class="hlt">Stratospheric</span> changes caused by geoengineering applications: potential repercussions and uncertainties</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kenzelmann, P.; Weisenstein, D.; Peter, T.; Luo, B. P.; Rozanov, E.; Fueglistaler, S.; Thomason, L. W.</p> <p>2009-04-01</p> <p>Anthropogenic greenhouse gas emissions tend to <span class="hlt">warm</span> the global climate, calling for significant rapid emission reductions. As potential support measures various ideas for geoengineering are currently being discussed. The assessment of the possible manifold and as yet substantially unexplored repercussions of implementing geoengineering ideas to ameliorate climate change poses enormous challenges not least in the realm of aerosol-cloud-climate interactions. Sulphur aerosols cool the Earth's surface by reflecting short wave radiation. By increasing the amount of sulphur aerosols in the <span class="hlt">stratosphere</span>, for example by sulphur dioxide injections, part of the anthropogenic climate <span class="hlt">warming</span> might be compensated due to enhanced albedo. However, we are only at the beginning of understanding possible side effects. One such effect that such aerosol might have is the <span class="hlt">warming</span> of the tropical tropopause and consequently the increase of the amount of <span class="hlt">stratospheric</span> water vapour. Using the 2D AER Aerosol Model we calculated the aerosol distributions for yearly injections of 1, 2, 5 and 10 Mt sulphur into the lower tropical <span class="hlt">stratosphere</span>. The results serve as input for the 3D chemistry-climate model SOCOL, which allows calculating the aerosol effect on <span class="hlt">stratospheric</span> temperatures and chemistry. In the injection region the continuously formed sulphuric acid condensates rapidly on sulphate aerosol, which eventually grow to such extent that they sediment down to the tropical tropopause region. The growth of the aerosol particles depends on non-linear processes: the more sulphur is emitted the faster the particles grow. As a consequence for the scenario with continuous sulphur injection of totally 10 Mt per year, only 6 Mt sulphur are in the <span class="hlt">stratosphere</span> if equilibrium is reached. According to our model calculations this amount of sulphate aerosols leads to a net surface forcing of -3.4 W/m2, which is less then expected radiative forcing by doubling of carbon dioxide concentration. Hence</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19840055075&hterms=Bromine&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3DBromine','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19840055075&hterms=Bromine&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3DBromine"><span id="translatedtitle">Measurements of <span class="hlt">stratospheric</span> bromine</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Sedlacek, W. A.; Lazrus, A. L.; Gandrud, B. W.</p> <p>1984-01-01</p> <p>From 1974 to 1977, molecules containing acidic bromine were sampled in the <span class="hlt">stratosphere</span> by using tetrabutyl ammonium hydroxide impregnated filters. Sampling was accomplished by WB-57F aircraft and high-altitude balloons, spanning latitudes from the equator to 75 deg N and altitudes up to 36.6 km. Analytical results are reported for 4 years of measurements and for laboratory simulations that determined the filter collection efficiencies for a number of brominated species. Mass mixing ratios for the collected bromine species in air average about 27 pptm in the <span class="hlt">stratosphere</span>. Seasonal variability seems to be small.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2010PhTea..48..525H&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2010PhTea..48..525H&link_type=ABSTRACT"><span id="translatedtitle">Global <span class="hlt">Warming</span>: Lessons from Ozone Depletion</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hobson, Art</p> <p>2010-11-01</p> <p>My teaching and textbook have always covered many physics-related social issues, including <span class="hlt">stratospheric</span> ozone depletion and global <span class="hlt">warming</span>. The ozone saga is an inspiring good-news story that's instructive for solving the similar but bigger problem of global <span class="hlt">warming</span>. Thus, as soon as students in my physics literacy course at the University of Arkansas have developed a conceptual understanding of energy and of electromagnetism, including the electromagnetic spectrum, I devote a lecture (and a textbook section) to ozone depletion and another lecture (and section) to global <span class="hlt">warming</span>. Humankind came together in 1986 and quickly solved, to the extent that humans can solve it, ozone depletion. We could do the same with global <span class="hlt">warming</span>, but we haven't and as yet there's no sign that we will. The parallel between the ozone and global <span class="hlt">warming</span> cases, and the difference in outcomes, are striking and instructive.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19770024750','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19770024750"><span id="translatedtitle">Chlorofluoromethanes and the <span class="hlt">Stratosphere</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Hudson, R. D. (Editor)</p> <p>1977-01-01</p> <p>The conclusions of a workshop held by the National Aeronautics and Space Administration to assess the current knowledge of the impact of chlorofluoromethane release in the troposphere on <span class="hlt">stratospheric</span> ozone concentrations. The following topics are discussed; (1) Laboratory measurements; (2) Ozone measurements and trends; (3) Minor species and aerosol measurements; (4) One dimensional modeling; and (5) Multidimensional modeling.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20140017638','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20140017638"><span id="translatedtitle">Northern Winter Climate Change: Assessment of Uncertainty in CMIP5 Projections Related to <span class="hlt">Stratosphere</span>-Troposphere Coupling</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Manzini, E.; Karpechko, A.Yu.; Anstey, J.; Shindell, Drew Todd; Baldwin, M.P.; Black, R.X.; Cagnazzo, C.; Calvo, N.; Charlton-Perez, A.; Christiansen, B.; Davini, Paolo; Gerber, E.; Giorgetta, M.; Gray, L.; Hardiman, S.C.; Lee, Y.-Y.; Marsh, D.R.; McDaniel, B.A.; Purich, A.; Scaife, A.A.; Shindell, Drew; Son, S.-W; Watanabe, S.; Zappa, G.</p> <p>2014-01-01</p> <p>Future changes in the <span class="hlt">stratospheric</span> circulation could have an important impact on northern winter tropospheric climate change, given that sea level pressure (SLP) responds not only to tropospheric circulation variations but also to vertically coherent variations in troposphere-<span class="hlt">stratosphere</span> circulation. Here we assess northern winter <span class="hlt">stratospheric</span> change and its potential to influence surface climate change in the Coupled Model Intercomparison Project-Phase 5 (CMIP5) multimodel ensemble. In the <span class="hlt">stratosphere</span> at high latitudes, an easterly change in zonally averaged zonal wind is found for the majority of the CMIP5 models, under the Representative Concentration Pathway 8.5 scenario. Comparable results are also found in the 1% CO2 increase per year projections, indicating that the <span class="hlt">stratospheric</span> easterly change is common feature in future climate projections. This <span class="hlt">stratospheric</span> wind change, however, shows a significant spread among the models. By using linear regression, we quantify the impact of tropical upper troposphere <span class="hlt">warming</span>, polar amplification, and the <span class="hlt">stratospheric</span> wind change on SLP. We find that the intermodel spread in <span class="hlt">stratospheric</span> wind change contributes substantially to the intermodel spread in Arctic SLP change. The role of the <span class="hlt">stratosphere</span> in determining part of the spread in SLP change is supported by the fact that the SLP change lags the <span class="hlt">stratospheric</span> zonally averaged wind change. Taken together, these findings provide further support for the importance of simulating the coupling between the <span class="hlt">stratosphere</span> and the troposphere, to narrow the uncertainty in the future projection of tropospheric circulation changes.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/5702593','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/5702593"><span id="translatedtitle">Scientific assessment of <span class="hlt">stratospheric</span> ozone: 1989, volume 1</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Not Available</p> <p>1989-01-01</p> <p>A review is presented of the current understanding of <span class="hlt">stratospheric</span> ozone (SO). The focus is on four major current aspects of SO: (1) polar ozone; (2) global trends; (3) theoretical predictions; and (4) halocarbon ozone depleting materials and global <span class="hlt">warming</span> potentials. Other ozone related topics are also discussed: (1) the trends of <span class="hlt">stratospheric</span> temperature, <span class="hlt">stratospheric</span> aerosols, source gases, and surface ultraviolet radiation; and (2) the oxidizing capacity of the troposphere as it pertains to the lifetimes of ozone related chemicals. There have been highly significant advances in the understanding of the impact of human activities on the Earth's protective ozone layer. There are four major findings that each heighten the concern that chlorine and bromine containing chemicals can lead to a significant depletion of SO: (1) Antarctic Ozone Hole; (2) Perturbed Arctic Chemistry; (3) Long-term Ozone Decreases; and (4) Model Limitations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013ACPD...1328869R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013ACPD...1328869R"><span id="translatedtitle">A Tropical West Pacific OH minimum and implications for <span class="hlt">stratospheric</span> composition</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Rex, M.; Wohltmann, I.; Ridder, T.; Lehmann, R.; Rosenlof, K.; Wennberg, P.; Weisenstein, D.; Notholt, J.; Krüger, K.; Mohr, V.; Tegtmeier, S.</p> <p>2013-11-01</p> <p>Hundreds of biogenic and anthropogenic chemical species are emitted into the atmosphere. Most break down efficiently by reaction with OH and do not reach the <span class="hlt">stratosphere</span>. Here we show the existence of pronounced minima in the tropospheric columns of ozone and OH over the West Pacific, the main source region for <span class="hlt">stratospheric</span> air. We show that this amplifies the impact of surface emissions on the <span class="hlt">stratospheric</span> composition. Specifically, emissions of biogenic halogenated species from natural sources and from kelp and seaweed farming can have a larger effect on <span class="hlt">stratospheric</span> ozone depletion. Increasing anthropogenic emissions of SO2 in South East Asia or from minor volcanic eruptions can play a larger role for the <span class="hlt">stratospheric</span> aerosol budget, a key element for explaining the recently observed decrease in global <span class="hlt">warming</span> rates (Solomon et al., 2011).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016EGUGA..1812060N&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016EGUGA..1812060N&link_type=ABSTRACT"><span id="translatedtitle">Validation of <span class="hlt">stratospheric</span> temperature profiles from a ground-based microwave radiometer with other techniques</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Navas, Francisco; Kämpfer, Niklaus; Haefele, Alexander; Keckhut, Philippe; Hauchecorne, Alain</p> <p>2016-04-01</p> <p>Vertical profiles of atmospheric temperature trends has become recognized as an important indicator of climate change, because different climate forcing mechanisms exhibit distinct vertical <span class="hlt">warming</span> and cooling patterns. For example, the cooling of the <span class="hlt">stratosphere</span> is an indicator for climate change as it provides evidence of natural and anthropogenic climate forcing just like surface <span class="hlt">warming</span>. Despite its importance, our understanding of the observed <span class="hlt">stratospheric</span> temperature trend and our ability to test simulations of the <span class="hlt">stratospheric</span> response to emissions of greenhouse gases and ozone depleting substances remains limited. One of the main reason is because <span class="hlt">stratospheric</span> long-term datasets are sparse and obtained trends differ from one another. Different techniques allow to measure <span class="hlt">stratospheric</span> temperature profiles as radiosonde, lidar or satellite. The main advantage of microwave radiometers against these other instruments is a high temporal resolution with a reasonable good spatial resolution. Moreover, the measurement at a fixed location allows to observe local atmospheric dynamics over a long time period, which is crucial for climate research. This study presents an evaluation of the <span class="hlt">stratospheric</span> temperature profiles from a newly ground-based microwave temperature radiometer (TEMPERA) which has been built and designed at the University of Bern. The measurements from TEMPERA are compared with the ones from other different techniques such as in-situ (radiosondes), active remote sensing (lidar) and passive remote sensing on board of Aura satellite (MLS) measurements. In addition a statistical analysis of the <span class="hlt">stratospheric</span> temperature obtained from TEMPERA measurements during four years of data has been performed. This analysis evidenced the capability of TEMPERA radiometer to monitor the temperature in the <span class="hlt">stratosphere</span> for a long-term. The detection of some singular sudden <span class="hlt">stratospheric</span> <span class="hlt">warming</span> (SSW) during the analyzed period shows the necessity of these</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20040085351','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20040085351"><span id="translatedtitle">Mesosphere-<span class="hlt">Stratosphere</span> Coupling: Implications for Climate Variability and Trends</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Baldwin, Mark P.</p> <p>2004-01-01</p> <p>A key aspect of this project is the establishment of a causal link from circulation anomalies in the lower mesosphere and stratopause region downward through the <span class="hlt">stratosphere</span> to the troposphere. The observational link for <span class="hlt">stratospheric</span> sudden <span class="hlt">warmings</span> and surface climate is fairly clear. However, our understanding of the dynamics is incomplete. We have been making significant progress in the area of dynamical mechanisms by which circulation anomalies in the <span class="hlt">stratosphere</span> affect the troposphere. We are trying to understand the details and sequence of events that occur when a middle atmosphere (wind) anomaly propagates downward to near the tropopause. The wind anomaly could be caused by a <span class="hlt">warming</span> or solar variations in the low-latitude stratopause region, or could have other causes. The observations show a picture that is consistent with a circulation anomaly that descends to the tropopause region, and can be detected as low as the mid-troposphere. Processes near the stratopause in the tropics appear to be important precursors to the wintertime development of the northern polar vortex. This may affect significantly our understanding of the process by which low-latitude wind anomalies in the low mesosphere and upper <span class="hlt">stratosphere</span> evolve through the winter and affect the polar vortex.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20050232880&hterms=stratosphere&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3Dstratosphere','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20050232880&hterms=stratosphere&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3Dstratosphere"><span id="translatedtitle">In-situ Observations of Mid-latitude Forest Fire Plumes Deep in the <span class="hlt">Stratosphere</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Jost, Hans-Juerg; Drdla, Katja; Stohl, Andreas; Pfister, Leonhard; Loewenstein, Max; Lopez, Jimena P.; Hudson, Paula K.; Murphy, Daniel M.; Cziczo, Daniel J.; Fromm, Michael</p> <p>2004-01-01</p> <p>We observed a plume of air highly enriched in carbon monoxide and particles in the <span class="hlt">stratosphere</span> at altitudes up to 15.8 km. It can be unambiguously attributed to North American forest fires. This plume demonstrates an extratropical direct transport path from the planetary boundary layer several kilometers deep into the <span class="hlt">stratosphere</span>, which is not fully captured by large-scale atmospheric transport models. This process indicates that the <span class="hlt">stratospheric</span> ozone layer could be sensitive to changes in forest burning associated with climatic <span class="hlt">warming</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20140001055','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20140001055"><span id="translatedtitle">Sensitivity of <span class="hlt">Stratospheric</span> Geoengineering with Black Carbon to Aerosol Size and Altitude of Injection</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Kravitz, Ben; Robock, Alan; Shindell, Drew T.; Miller, Mark A.</p> <p>2012-01-01</p> <p>Simulations of <span class="hlt">stratospheric</span> geoengineering with black carbon (BC) aerosols using a general circulation model with fixed sea surface temperatures show that the climate effects strongly depend on aerosol size and altitude of injection. 1 Tg BC/a injected into the lower <span class="hlt">stratosphere</span> would cause little surface cooling for large radii but a large amount of surface cooling for small radii and <span class="hlt">stratospheric</span> <span class="hlt">warming</span> of over 60 C. With the exception of small particles, increasing the altitude of injection increases surface cooling and <span class="hlt">stratospheric</span> <span class="hlt">warming</span>. <span class="hlt">Stratospheric</span> <span class="hlt">warming</span> causes global ozone loss by up to 50% in the small radius case. The Antarctic shows less ozone loss due to reduction of polar <span class="hlt">stratospheric</span> clouds, but strong circumpolar winds would enhance the Arctic ozone hole. Using diesel fuel to produce the aerosols is likely prohibitively expensive and infeasible. Although studying an absorbing aerosol is a useful counterpart to previous studies involving sulfate aerosols, black carbon geoengineering likely carries too many risks to make it a viable option for deployment.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/17569652','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/17569652"><span id="translatedtitle">Ensemble climate simulations using a fully coupled ocean-troposphere-<span class="hlt">stratosphere</span> general circulation model.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Huebener, H; Cubasch, U; Langematz, U; Spangehl, T; Niehörster, F; Fast, I; Kunze, M</p> <p>2007-08-15</p> <p>Long-term transient simulations are carried out in an initial condition ensemble mode using a global coupled climate model which includes comprehensive ocean and <span class="hlt">stratosphere</span> components. This model, which is run for the years 1860-2100, allows the investigation of the troposphere-<span class="hlt">stratosphere</span> interactions and the importance of representing the middle atmosphere in climate-change simulations. The model simulates the present-day climate (1961-2000) realistically in the troposphere, <span class="hlt">stratosphere</span> and ocean. The enhanced <span class="hlt">stratospheric</span> resolution leads to the simulation of sudden <span class="hlt">stratospheric</span> <span class="hlt">warmings</span>; however, their frequency is underestimated by a factor of 2 with respect to observations.In projections of the future climate using the Intergovernmental Panel on Climate Change special report on emissions scenarios A2, an increased tropospheric wave forcing counteracts the radiative cooling in the middle atmosphere caused by the enhanced greenhouse gas concentration. This leads to a more dynamically active, warmer <span class="hlt">stratosphere</span> compared with present-day simulations, and to the doubling of the number of <span class="hlt">stratospheric</span> <span class="hlt">warmings</span>. The associated changes in the mean zonal wind patterns lead to a southward displacement of the Northern Hemisphere storm track in the climate-change signal. PMID:17569652</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li class="active"><span>10</span></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_10 --> <div id="page_11" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li class="active"><span>11</span></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="201"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013JGRD..118..563A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013JGRD..118..563A"><span id="translatedtitle"><span class="hlt">Stratospheric</span> ozone and the morphology of the northern hemisphere planetary waveguide</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Albers, John R.; McCormack, John P.; Nathan, Terrence R.</p> <p>2013-01-01</p> <p>A middle atmosphere general circulation model is used to examine the effects of zonally asymmetric ozone (ZAO) on the Northern Hemisphere planetary waveguide (PWG) during winter (December-February). The morphology of the PWG is measured by a refractive index, Eliassen-Palm flux vectors, the latitude of the subtropical zero wind line, and the latitude of the subtropical jet. ZAO causes the PWG to contract meridionally in the upper <span class="hlt">stratosphere</span>, expand meridionally in the lower <span class="hlt">stratosphere</span>, and expand vertically in the upper <span class="hlt">stratosphere</span> and lower mesosphere. The ZAO-induced changes in the PWG are the result of increased upward and poleward flux of planetary wave activity into the extratropical <span class="hlt">stratosphere</span> and lower mesosphere. These changes cause an increase in the Eliassen-Palm flux convergence at high latitudes, which produces a warmer and weaker <span class="hlt">stratospheric</span> polar vortex and an increase in the frequency of <span class="hlt">stratospheric</span> sudden <span class="hlt">warmings</span>. The ability of ZAO to alter the flux of planetary wave activity into the polar vortex has important implications for accurately modeling wave-modulated and wave-driven phenomena in the middle atmosphere, including the 11-year solar cycle, <span class="hlt">stratospheric</span> sudden <span class="hlt">warmings</span>, and the phase of the Northern Hemisphere annular mode.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015JASTP.136..201S&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015JASTP.136..201S&link_type=ABSTRACT"><span id="translatedtitle">Generation of waves by jet-stream instabilities in winter polar <span class="hlt">stratosphere</span>/mesosphere</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Shpynev, B. G.; Churilov, S. M.; Chernigovskaya, M. A.</p> <p>2015-12-01</p> <p>In the paper we investigate the manifestation of large-scale and middle-scale atmospheric irregularities observed on <span class="hlt">stratosphere</span>/mesosphere heights. We consider typical patterns of circulation in <span class="hlt">stratosphere</span> and lower mesosphere which are formed due to a difference of air potential energy between equatorial and polar latitudes, especially in polar night conditions. On the base of ECMWF Era Interim reanalysis data we consider the dynamics of midlatitude winter jet-streams which transfer heat from low latitudes to polar region and which develop due to equator/pole baroclinic instabilities. We consider typical patterns of general circulation in <span class="hlt">stratosphere</span>/lower mesosphere and reasons for creation of flaky structure of polar <span class="hlt">stratosphere</span>. Also we analyze conditions that are favorable for splitting of winter circumpolar vortex during sudden <span class="hlt">stratosphere</span> <span class="hlt">warming</span> events and role of phase difference tides in this process. The analysis of vertical structure of the <span class="hlt">stratosphere</span> wind shows the presence of regions with significant shear of horizontal velocity which favors for inducing of shear-layer instability that appears as gravity wave on boundary surface. During powerful sudden <span class="hlt">stratosphere</span> <span class="hlt">warming</span> events the main jet-stream can amplify these gravity waves to very high amplitudes that causes wave overturning and releasing of wave energy into the heat due to the cascade breakdown and turbulence. For the dynamics observed in reanalysis data we consider physical mechanisms responsible for observed phenomena.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/1008259','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/1008259"><span id="translatedtitle">Impact of geoengineered aerosols on the troposphere and <span class="hlt">stratosphere</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Tilmes, S.; Garcia, Rolando R.; Kinnison, Douglas E.; Gettelman, A.; Rasch, Philip J.</p> <p>2009-06-27</p> <p>A coupled chemistry climate model, the Whole Atmosphere Community Climate Model was used to perform a transient climate simulation to quantify the impact of geoengineered aerosols on atmospheric processes. In contrast to previous model studies, the impact on <span class="hlt">stratospheric</span> chemistry, including heterogeneous chemistry in the polar regions, is considered in this simulation. In the geoengineering simulation, a constant <span class="hlt">stratospheric</span> distribution of volcanic-sized, liquid sulfate aerosols is imposed in the period 2020–2050, corresponding to an injection of 2 Tg S/a. The aerosol cools the troposphere compared to a baseline simulation. Assuming an Intergovernmental Panel on Climate Change A1B emission scenario, global <span class="hlt">warming</span> is delayed by about 40 years in the troposphere with respect to the baseline scenario. Large local changes of precipitation and temperatures may occur as a result of geoengineering. Comparison with simulations carried out with the Community Atmosphere Model indicates the importance of <span class="hlt">stratospheric</span> processes for estimating the impact of <span class="hlt">stratospheric</span> aerosols on the Earth’s climate. Changes in <span class="hlt">stratospheric</span> dynamics and chemistry, especially faster heterogeneous reactions, reduce the recovery of the ozone layer in middle and high latitudes for the Southern Hemisphere. In the geoengineering case, the recovery of the Antarctic ozone hole is delayed by about 30 years on the basis of this model simulation. For the Northern Hemisphere, a onefold to twofold increase of the chemical ozone depletion occurs owing to a simulated stronger polar vortex and colder temperatures compared to the baseline simulation, in agreement with observational estimates.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20040031806&hterms=space+travelling&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dspace%2Btravelling','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20040031806&hterms=space+travelling&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dspace%2Btravelling"><span id="translatedtitle">On the Eastward Travelling Wavenumber Two in the Northern <span class="hlt">Stratosphere</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Pawson, Steven; Krueger, Kirstin</p> <p>2003-01-01</p> <p>Disturbances in the middle atmosphere are often interpreted in the framework of waves superimposed on a zonal-mean flow. This paper presents an analysis of travelling waves in the northern hemisphere <span class="hlt">stratosphere</span>, concentrating on planetary wavenumber two (W2). Space-time spectral analysis reveals the existence of a substantial eastward-travelling planetary W2 at high latitudes in winter. While a similar feature is well documented in the southern hemisphere <span class="hlt">stratosphere</span>, where it is observed in most winters, this northern hemisphere counterpart is less common and has not been examined in detail. A climatology of occurrence of the wave is given for the northern <span class="hlt">stratospheric</span> winter. It is denoted as the quasi-16-day eastward travelling W2, because of its dominant periodicity, which ranges from about one to three weeks. Although the wave has some similarities with the southern hemispheric wave, there is much larger interannual and intraseasonal variability in the northern hemisphere. will emphasize the variations in the spatial and temporal structure of this wave, as isolated in meteorological analyses of radiosonde and satellite data. The possible role of these travelling waves in preconditioning the <span class="hlt">stratosphere</span> as a precursor to sudden <span class="hlt">stratospheric</span> <span class="hlt">warmings</span> in both hemispheres will be discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/7129539','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/7129539"><span id="translatedtitle">Antarctic <span class="hlt">stratospheric</span> ice crystals</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Goodman, J. ); Toon, O.B.; Pueschel, R.F.; Snetsinger, K.G. ) Verma, S. )</p> <p>1989-11-30</p> <p>Ice crystals were replicated over the Palmer Peninsula at approximately 72{degree}S on six occasions during the 1987 Airborne Antarctic Ozone Experiment. The sampling altitude was between 12.5 and 18.5 km (45-65 thousand ft pressure altitude) with the temperature between 190 and 201 K. The atmosphere was subsaturated with respect to ice in all cases. The collected crystals were predominantly solid and hollow columns. The largest crystals were sampled at lower altitudes where the potential temperature was below 400 K. While the crystals were larger than anticipated, their low concentration results in a total surface area that is less than one tenth of the total aerosol surface area. The large ice crystals may play an important role in the observed <span class="hlt">stratospheric</span> dehydration processes through sedimentation. Evidence of scavenging of submicron particles further suggests that the ice crystals may be effective in the removal of <span class="hlt">stratospheric</span> chemicals.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013grcc.book...21K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013grcc.book...21K"><span id="translatedtitle"><span class="hlt">Stratospheric</span> Aerosols for Solar Radiation Management</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kravitz, Ben</p> <p></p> <p>SRM in the context of this entry involves placing a large amount of aerosols in the <span class="hlt">stratosphere</span> to reduce the amount of solar radiation reaching the surface, thereby cooling the surface and counteracting some of the <span class="hlt">warming</span> from anthropogenic greenhouse gases. The way this is accomplished depends on the specific aerosol used, but the basic mechanism involves backscattering and absorbing certain amounts of solar radiation aloft. Since <span class="hlt">warming</span> from greenhouse gases is due to longwave (thermal) emission, compensating for this <span class="hlt">warming</span> by reduction of shortwave (solar) energy is inherently imperfect, meaning SRM will have climate effects that are different from the effects of climate change. This will likely manifest in the form of regional inequalities, in that, similarly to climate change, some regions will benefit from SRM, while some will be adversely affected, viewed both in the context of present climate and a climate with high CO2 concentrations. These effects are highly dependent upon the means of SRM, including the type of aerosol to be used, the particle size and other microphysical concerns, and the methods by which the aerosol is placed in the <span class="hlt">stratosphere</span>. SRM has never been performed, nor has deployment been tested, so the research up to this point has serious gaps. The amount of aerosols required is large enough that SRM would require a major engineering endeavor, although SRM is potentially cheap enough that it could be conducted unilaterally. Methods of governance must be in place before deployment is attempted, should deployment even be desired. Research in public policy, ethics, and economics, as well as many other disciplines, will be essential to the decision-making process. SRM is only a palliative treatment for climate change, and it is best viewed as part of a portfolio of responses, including mitigation, adaptation, and possibly CDR. At most, SRM is insurance against dangerous consequences that are directly due to increased surface air</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFM.A12A..02D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFM.A12A..02D"><span id="translatedtitle">A <span class="hlt">stratospheric</span> water vapor feedback</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Dessler, A. E.; Schoeberl, M. R.; Wang, T.; Davis, S. M.; Rosenlof, K. H.</p> <p>2013-12-01</p> <p>Variations in <span class="hlt">stratospheric</span> water vapor play a role in the evolution of our climate. We show here that variations in water vapor since 2004 can be traced to tropical tropopause layer (TTL) temperature perturbations from at least three processes: the quasi-biennial oscillation, the strength of the Brewer-Dobson circulation, and the temperature of the troposphere. The connection between <span class="hlt">stratospheric</span> water vapor and the temperature of the troposphere implies the existence of a <span class="hlt">stratospheric</span> water vapor feedback. We estimate the feedback in a chemistry-climate model to have a magnitude of +0.3 W/m2/K, which could be a significant contributor to the overall climate sensitivity. About two-thirds of the feedback comes from the extratropical <span class="hlt">stratosphere</span> below ~16 km (the lowermost <span class="hlt">stratosphere</span>), with the rest coming from the <span class="hlt">stratosphere</span> above ~16 km (the overworld).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19980006745','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19980006745"><span id="translatedtitle">Science in the <span class="hlt">Stratosphere</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Lester, Dan</p> <p>1997-01-01</p> <p>The Science in the <span class="hlt">Stratosphere</span> program, first established in 1992, was conceived to introduce K-6 teachers to airborne infrared astronomy through the Kuiper Airborne Observatory (KAO), and to use this venue as a basis for seeing scientists at work in a mission-intensive program. The teachers selected for this program would bring their new perspectives back to their schools and students. Unlike the related FOSTER program, the emphasis of this program was on more intensive exposure of the KAO mission to a small number of teachers. The teachers in the Science in the <span class="hlt">Stratosphere</span> program essentially lived with the project scientists and staff for almost a week. One related goal was to imbed the KAO project with perspectives of working teachers, thereby sensitizing the project staff and scientists to educational outreach efforts in general, which is an important goal of the NASA airborne astronomy program. A second related goal was to explore the ways in which K-5 educators could participate in airborne astronomy missions. Also unlike FOSTER, the Science in the <span class="hlt">Stratosphere</span> program was intentionally relatively unstructured, in that the teacher participants were wholly embraced by the science team, and were encouraged to 'sniff out' the flavor of the whole facility by talking with people.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19930040390&hterms=eruptions+volcanic&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Deruptions%2Bvolcanic','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19930040390&hterms=eruptions+volcanic&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Deruptions%2Bvolcanic"><span id="translatedtitle">Winter <span class="hlt">warming</span> from large volcanic eruptions</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Robock, Alan; Mao, Jianping</p> <p>1992-01-01</p> <p>An examination of the Northern Hemisphere winter surface temperature patterns after the 12 largest volcanic eruptions from 1883-1992 shows <span class="hlt">warming</span> over Eurasia and North America and cooling over the Middle East which are significant at the 95-percent level. This pattern is found in the first winter after tropical eruptions, in the first or second winter after midlatitude eruptions, and in the second winter after high latitude eruptions. The effects are independent of the hemisphere of the volcanoes. An enhanced zonal wind driven by heating of the tropical <span class="hlt">stratosphere</span> by the volcanic aerosols is responsible for the regions of <span class="hlt">warming</span>, while the cooling is caused by blocking of incoming sunlight.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/6459161','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/6459161"><span id="translatedtitle">Winter <span class="hlt">warming</span> from large volcanic eruptions</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Robock, A.; Mao, J.</p> <p>1992-01-01</p> <p>An examination of the Northern Hemisphere winter surface temperature patterns after the 12 largest volcanic eruptions from 1883-1992 shows <span class="hlt">warming</span> over Eurasia and North America and cooling over the Middle East which are significant at the 95 percent level. This pattern is found in the first winter after tropical eruptions, in the first or second winter after midlatitude eruptions, and in the second winter after high latitude eruptions. The effects are independent of the hemisphere of the volcanoes. An enhanced zonal wind driven by heating of the tropical <span class="hlt">stratosphere</span> by the volcanic aerosols is responsible for the regions of <span class="hlt">warming</span>, while the cooling is caused by blocking of incoming sunlight.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19970004797','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19970004797"><span id="translatedtitle">Freezing Behavior of <span class="hlt">Stratospheric</span> Sulfate Aerosols Inferred from Trajectory Studies</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Tabazadeh, A.; Toon, O. B.; Hamill, Patrick</p> <p>1995-01-01</p> <p>Based on the trajectory analysis presented in this paper, a new mechanism is described for the freezing of the <span class="hlt">stratospheric</span> sulfate aerosols. Temperature histories based on 10-day back trajectories for six ER-2 flights during AASE-I (1989) and AAOE (1987) are presented. The mechanism requires, as an initial step, the cooling of a H2SO4/H2O aerosol to low temperatures. If a cooling cycle is then followed up by a <span class="hlt">warming</span> to approximately 196-198 K, the aerosols may freeze due to the growth of the crystallizing embryos formed at the colder temperature. The HNO3 absorbed at colder temperatures may increase the nucleation rate of the crystalling embryos and therefore influence the crystallization of the supercooled aerosols upon <span class="hlt">warming</span>. Of all the ER-2 flights described, only the polar <span class="hlt">stratospheric</span> clouds (PSC), observed on the flights of January 24, and 25, 1989 are consistent with the thermodynamics of liquid ternary solutions of H2SO4/HNO3/H2O (type Ib PSCs). For those two days, back trajectories indicate that the air mass was exposed to sulfuric acid tetrahydrate (SAT) melting temperatures about 24 hours prior to being sampled by the ER-2. Temperature histories, recent laboratory measurements, and the properties of glassy solids suggest that <span class="hlt">stratospheric</span> H2SO4 aerosols may undergo a phase transition to SAT upon <span class="hlt">warming</span> at approximately 198 K after going through a cooling cycle to about 194 K or lower.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://eric.ed.gov/?q=evidence+AND+global+AND+warming&pg=2&id=EJ484206','ERIC'); return false;" href="http://eric.ed.gov/?q=evidence+AND+global+AND+warming&pg=2&id=EJ484206"><span id="translatedtitle">Global <span class="hlt">Warming</span>?</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Eichman, Julia Christensen; Brown, Jeff A.</p> <p>1994-01-01</p> <p>Presents information and data on an experiment designed to test whether different atmosphere compositions are affected by light and temperature during both cooling and heating. Although flawed, the experiment should help students appreciate the difficulties that researchers face when trying to find evidence of global <span class="hlt">warming</span>. (PR)</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011ACP....11.7687H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011ACP....11.7687H"><span id="translatedtitle">Tropospheric temperature response to <span class="hlt">stratospheric</span> ozone recovery in the 21st century</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hu, Y.; Xia, Y.; Fu, Q.</p> <p>2011-08-01</p> <p>Recent simulations predicted that the <span class="hlt">stratospheric</span> ozone layer will likely return to pre-1980 levels in the middle of the 21st century, as a result of the decline of ozone depleting substances under the Montreal Protocol. Since the ozone layer is an important component in determining <span class="hlt">stratospheric</span> and tropospheric-surface energy balance, the recovery of <span class="hlt">stratospheric</span> ozone may have significant impact on tropospheric-surface climate. Here, using multi-model results from both the Intergovernmental Panel on Climate Change Fourth Assessment Report (IPCC-AR4) models and coupled chemistry-climate models, we show that as ozone recovery is considered, the troposphere is <span class="hlt">warmed</span> more than that without considering ozone recovery, suggesting an enhancement of tropospheric <span class="hlt">warming</span> due to ozone recovery. It is found that the enhanced tropospheric <span class="hlt">warming</span> is mostly significant in the upper troposphere, with a global and annual mean magnitude of ~0.41 K for 2001-2050. We also find that relatively large enhanced <span class="hlt">warming</span> occurs in the extratropics and polar regions in summer and autumn in both hemispheres, while the enhanced <span class="hlt">warming</span> is stronger in the Northern Hemisphere than in the Southern Hemisphere. Enhanced <span class="hlt">warming</span> is also found at the surface. The global and annual mean enhancement of surface <span class="hlt">warming</span> is about 0.16 K for 2001-2050, with maximum enhancement in the winter Arctic.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/963441','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/963441"><span id="translatedtitle">Sudden <span class="hlt">stratospheric</span> <span class="hlt">warmings</span> seen in MINOS deep underground muon data</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Osprey, S.; Barnett, J.; Smith, J.; Adamson, P.; Andreopoulos, C.; Arms, K.E.; Armstrong, R.; Auty, D.J.; Ayres, D.S.; Baller, B.; Barnes, P.D., Jr.; /LLNL, Livermore /Oxford U.</p> <p>2009-01-01</p> <p>The rate of high energy cosmic ray muons as measured underground is shown to be strongly correlated with upper-air temperatures during short-term atmospheric (10-day) events. The effects are seen by correlating data from the MINOS underground detector and temperatures from the European Centre for Medium Range Weather Forecasts during the winter periods from 2003-2007. This effect provides an independent technique for the measurement of meteorological conditions and presents a unique opportunity to measure both short and long-term changes in this important part of the atmosphere.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015ClDy..tmp..364R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015ClDy..tmp..364R"><span id="translatedtitle">A decomposition of ENSO's impacts on the northern winter <span class="hlt">stratosphere</span>: competing effect of SST forcing in the tropical Indian Ocean</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Rao, Jian; Ren, Rongcai</p> <p>2015-09-01</p> <p>This study applies WACCM, a <span class="hlt">stratosphere</span>-resolving model to dissect the <span class="hlt">stratospheric</span> responses in the northern winter extratropics to the imposed ENSO-related SST anomalies in the tropics. It is found that the anomalously warmer and weaker <span class="hlt">stratospheric</span> polar vortex during <span class="hlt">warm</span> ENSO is basically a balance of the opposite effects between the SST anomalies in the tropical Pacific (TPO) and that over the tropical Indian Ocean basin (TIO). Specifically, the ENSO-related SST anomalies over the TIO are to induce an anomalously colder and stronger <span class="hlt">stratospheric</span> polar vortex during <span class="hlt">warm</span> ENSO, which acts to partially cancel out the much stronger warmer and weaker polar vortex response to the SST anomalies over the TPO. Further analysis indicates that, while the SST forcing from the TPO contributes to the anomalously positive Pacific North America (PNA) pattern in the troposphere and the enhancement of the stationary wavenumber (WN)-1 in the <span class="hlt">stratosphere</span> during <span class="hlt">warm</span> ENSO, the TIO SST forcing is to induce an anomalously negative PNA and a reduction of both WN-1 and WN-2 in the <span class="hlt">stratosphere</span>. Diagnosis of E-P flux confirms that, the anomalously upward propagation of stationary waves in the extratropics mainly lies over the western coast of North America during <span class="hlt">warm</span> ENSO, which is mainly associated with the TPO-induced positive PNA response and is partially suppressed by the effect of the accompanying TIO SST forcing.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016ClDy...46.3689R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016ClDy...46.3689R"><span id="translatedtitle">A decomposition of ENSO's impacts on the northern winter <span class="hlt">stratosphere</span>: competing effect of SST forcing in the tropical Indian Ocean</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Rao, Jian; Ren, Rongcai</p> <p>2016-06-01</p> <p>This study applies WACCM, a <span class="hlt">stratosphere</span>-resolving model to dissect the <span class="hlt">stratospheric</span> responses in the northern winter extratropics to the imposed ENSO-related SST anomalies in the tropics. It is found that the anomalously warmer and weaker <span class="hlt">stratospheric</span> polar vortex during <span class="hlt">warm</span> ENSO is basically a balance of the opposite effects between the SST anomalies in the tropical Pacific (TPO) and that over the tropical Indian Ocean basin (TIO). Specifically, the ENSO-related SST anomalies over the TIO are to induce an anomalously colder and stronger <span class="hlt">stratospheric</span> polar vortex during <span class="hlt">warm</span> ENSO, which acts to partially cancel out the much stronger warmer and weaker polar vortex response to the SST anomalies over the TPO. Further analysis indicates that, while the SST forcing from the TPO contributes to the anomalously positive Pacific North America (PNA) pattern in the troposphere and the enhancement of the stationary wavenumber (WN)-1 in the <span class="hlt">stratosphere</span> during <span class="hlt">warm</span> ENSO, the TIO SST forcing is to induce an anomalously negative PNA and a reduction of both WN-1 and WN-2 in the <span class="hlt">stratosphere</span>. Diagnosis of E-P flux confirms that, the anomalously upward propagation of stationary waves in the extratropics mainly lies over the western coast of North America during <span class="hlt">warm</span> ENSO, which is mainly associated with the TPO-induced positive PNA response and is partially suppressed by the effect of the accompanying TIO SST forcing.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19800006383','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19800006383"><span id="translatedtitle">The <span class="hlt">stratosphere</span>: Present and future</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Hudson, R. D. (Editor); Reed, E. I. (Editor)</p> <p>1979-01-01</p> <p>The present status of <span class="hlt">stratospheric</span> science is discussed. The three basic elements of <span class="hlt">stratospheric</span> science-laboratory measurements, atmospheric observations, and theoretical studies are presented along with an attempt to predict, with reasonable confidence, the effect on ozone of particular anthropogenic sources of pollution.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008AGUFM.U41E..05T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008AGUFM.U41E..05T"><span id="translatedtitle"><span class="hlt">Stratospheric</span> Aerosol Injection for Geoengineering Purposes</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Turco, R. P.; Yu, F.</p> <p>2008-12-01</p> <p>A number of studies have focused on the large-scale aspects of massive <span class="hlt">stratospheric</span> aerosol injections for the purpose of modifying global climate to counterbalance current and future greenhouse <span class="hlt">warming</span> effects. However, no descriptions of actual injection schemes have been presented at any level of detail; it is generally assumed that the procedure would be straightforward. Approaches mentioned include direct injection of dispersed microparticles of sulfates or other mineral particles, or the emission of precursor vapors, such as sulfur dioxide or hydrogen sulfide, that lead to particle formation. Using earlier aircraft plume research as a guide, we investigate the fate of injected aerosols/precursors from a <span class="hlt">stratospheric</span> platform in terms of the chemical and microphysical evolution occurring in a mixing plume. We utilize an advanced microphysics model that treats nucleation, coagulation, condensation and other processes relevant to the injection of particulates at high altitudes, as well as the influence of plume dilution. The requirements of particle size and concentration for producing the desired engineered radiative forcing place significant constraints on the injection system. Here, we focus on the effects of early microphysical processing on the formation of a suitable aerosol layer, and consider strategies to overcome potential hurdles. Among the problems explicitly addressed are: the propensity for emitted particles to coagulate to sizes that are optically inefficient at solar wavelengths, accelerated scavenging by an enhanced background aerosol layer, the evolution of size dispersion leading to significant infrared effects, and total mass injection rates implied by <span class="hlt">stratospheric</span> residence times. We also investigate variability in aerosol properties owing to uncertain nucleation rates in evolving plumes. In the context of the microphysical simulations, we discuss infrastructure requirements in terms of the scale of the intervention and, hence, the</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2005RPPh...68.1343H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2005RPPh...68.1343H"><span id="translatedtitle">Global <span class="hlt">warming</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Houghton, John</p> <p>2005-06-01</p> <p>'Global <span class="hlt">warming</span>' is a phrase that refers to the effect on the climate of human activities, in particular the burning of fossil fuels (coal, oil and gas) and large-scale deforestation, which cause emissions to the atmosphere of large amounts of 'greenhouse gases', of which the most important is carbon dioxide. Such gases absorb infrared radiation emitted by the Earth's surface and act as blankets over the surface keeping it warmer than it would otherwise be. Associated with this <span class="hlt">warming</span> are changes of climate. The basic science of the 'greenhouse effect' that leads to the <span class="hlt">warming</span> is well understood. More detailed understanding relies on numerical models of the climate that integrate the basic dynamical and physical equations describing the complete climate system. Many of the likely characteristics of the resulting changes in climate (such as more frequent heat waves, increases in rainfall, increase in frequency and intensity of many extreme climate events) can be identified. Substantial uncertainties remain in knowledge of some of the feedbacks within the climate system (that affect the overall magnitude of change) and in much of the detail of likely regional change. Because of its negative impacts on human communities (including for instance substantial sea-level rise) and on ecosystems, global <span class="hlt">warming</span> is the most important environmental problem the world faces. Adaptation to the inevitable impacts and mitigation to reduce their magnitude are both necessary. International action is being taken by the world's scientific and political communities. Because of the need for urgent action, the greatest challenge is to move rapidly to much increased energy efficiency and to non-fossil-fuel energy sources.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012cosp...39.1147M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012cosp...39.1147M"><span id="translatedtitle">Studies on the Effect of Cloud Coverage and Galactic Cosmic Ray on <span class="hlt">Stratospheric</span> Moistening</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Maitra, Animesh; Saha, Upal; Das, Saurabh</p> <p>2012-07-01</p> <p>Increased <span class="hlt">stratospheric</span> water vapor is one of the significant causes of global <span class="hlt">warming</span> as increased <span class="hlt">stratospheric</span> water vapor acts to cool the <span class="hlt">stratosphere</span> but it <span class="hlt">warms</span> the underlying troposphere. The sun can influence the clouds by mediating through Galactic cosmic rays (GCR) which controls the nucleation of water droplets in the atmosphere. The role of primary GCR in generating low-level cloud condensation nuclei reflects solar energy back into space affecting the temperature on earth. In the present study, variations of different types of cloud coverage (low, mid and high) are correlated with the intensity of GCR flux and their effects on the <span class="hlt">stratospheric</span> moistening in the equatorial, mid- latitude and polar region have been investigated for the years 2004 and 2005 using the Aura's Microwave Limb Sounder (MLS) water vapor data, ISCCP cloud data and GCR from neutron monitor observations at Calgary (51.080 N, 245.870 E). The relation between GCR and <span class="hlt">stratospheric</span> moistening is also investigated in this paper. Additionally, the latitudinal variation of different types of cloud coverage is also studied for the same period. The southern mid-latitudinal region has the highest coverage of low-level cloud, followed by the equatorial region. Both the Polar Regions are highly covered with mid-level cloud. The mid-latitudinal region shows highest coverage of high-cloud, followed by the equatorial region. Lower level clouds exert a large net cooling effect on the climate indicating an inter-relationship between cosmic ray and cloud coverage. However, the mid and high cloud coverage have no significant correlation with GCR flux. The <span class="hlt">stratospheric</span> moistening is controlled by transport of water vapour from troposphere to <span class="hlt">stratosphere</span> through the tropopause region and the oxidation of methane within the <span class="hlt">stratosphere</span>. Water vapour plays a major role in the chemistry and radiative budget of the <span class="hlt">stratosphere</span>. One possible water vapor source in the <span class="hlt">stratosphere</span> is the advection of</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li class="active"><span>11</span></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_11 --> <div id="page_12" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li class="active"><span>12</span></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="221"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19760087420&hterms=summer+camp&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dsummer%2Bcamp','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19760087420&hterms=summer+camp&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dsummer%2Bcamp"><span id="translatedtitle"><span class="hlt">Stratospheric</span> aerosols and climatic change</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Baldwin, B.; Pollack, J. B.; Summers, A.; Toon, O. B.; Sagan, C.; Van Camp, W.</p> <p>1976-01-01</p> <p>Generated primarily by volcanic explosions, a layer of submicron silicate particles and particles made of concentrated sulfuric acids solution is present in the <span class="hlt">stratosphere</span>. Flights through the <span class="hlt">stratosphere</span> may be a future source of <span class="hlt">stratospheric</span> aerosols, since the effluent from supersonic transports contains sulfurous gases (which will be converted to H2SO4) while the exhaust from Space Shuttles contains tiny aluminum oxide particles. Global heat balance calculations have shown that the <span class="hlt">stratospheric</span> aerosols have made important contributions to some climatic changes. In the present paper, accurate radiative transfer calculations of the globally-averaged surface temperature (T) are carried out to estimate the sensitivity of the climate to changes in the number of <span class="hlt">stratospheric</span> aerosols. The results obtained for a specified model atmosphere, including a vertical profile of the aerosols, indicate that the climate is unlikely to be affected by supersonic transports and Space Shuttles, during the next decades.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19950036038&hterms=Motion+pictures&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3DMotion%2Bpictures','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19950036038&hterms=Motion+pictures&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3DMotion%2Bpictures"><span id="translatedtitle">On the motion of air through the <span class="hlt">stratospheric</span> polar vortex</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Manney, G. L.; Zurek, R. W.; O'Neill, A.; Swinbank, R.</p> <p>1994-01-01</p> <p>Trajectory calculations using horizontal winds from the U.K. Meteorological Office data assimilation system and vertical velocities from a radiation calculation are used to simulate the three-dimensional motion of air through the <span class="hlt">stratospheric</span> polar vortex for Northern Hemisphere (NH) and Southern Hemisphere (SH) winters since the launch of the Upper Atmosphere Research Satellite (UARS). Throughout the winter, air from the upper <span class="hlt">stratosphere</span> moves poleward and descends into the middle <span class="hlt">stratosphere</span>. In the SH lower to middle <span class="hlt">stratosphere</span>, strongest descent occurs near the edge of the polar vortex, with that edge defined by mixing characteristics. The NH shows a similar pattern in late winter, but in early winter strongest descent is near the center of the vortex, except when wave activity is particularly strong. Strong barriers to latitudinal mixing exist above about 420 K throughout the winter. Below this, the polar night jet is weak in early winter, so air descending below that level mixes between polar and middle latitudes. In late winter, parcels descend less and the polar night jet moves downward, so there is less latitudinal mixing. The degree of mixing in the lower <span class="hlt">stratosphere</span> thus depends strongly on the position and evolution of the polar night jet and on the amount of descent experienced by the air parcels; these characteristics show considerable interannual variability in both hemispheres. The computed trajectories provide a three-dimensional picture of air motion during the final <span class="hlt">warming</span>. Large tongues of air are drawn off the vortex and stretched into increasingly long and narrow tongues extending into low latitudes. This vortex erosion process proceeds more rapidly in the NH than in he SH. In the lower <span class="hlt">stratosphere</span>, the majority of air parcels remain confined within a lingering region of strong potential vorticity gradients into December in the SH and April in the NH, well after the vortex breaks up in the midstratosphere.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20070034992&hterms=global+warming+climate&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Dglobal%2Bwarming%2Bclimate','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20070034992&hterms=global+warming+climate&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Dglobal%2Bwarming%2Bclimate"><span id="translatedtitle">AO/NAO Response to Climate Change. 1; Respective Influences of <span class="hlt">Stratospheric</span> and Tropospheric Climate Changes</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Rind, D.; Perlwitz, J.; Lonergan, P.</p> <p>2005-01-01</p> <p>We utilize the GISS Global Climate Middle Atmosphere Model and 8 different climate change experiments, many of them focused on <span class="hlt">stratospheric</span> climate forcings, to assess the relative influence of tropospheric and <span class="hlt">stratospheric</span> climate change on the extratropical circulation indices (Arctic Oscillation, AO; North Atlantic Oscillation, NAO). The experiments are run in two different ways: with variable sea surface temperatures (SSTs) to allow for a full tropospheric climate response, and with specified SSTs to minimize the tropospheric change. The results show that tropospheric <span class="hlt">warming</span> (cooling) experiments and <span class="hlt">stratospheric</span> cooling (<span class="hlt">warming</span>) experiments produce more positive (negative) AO/NAO indices. For the typical magnitudes of tropospheric and <span class="hlt">stratospheric</span> climate changes, the tropospheric response dominates; results are strongest when the tropospheric and <span class="hlt">stratospheric</span> influences are producing similar phase changes. Both regions produce their effect primarily by altering wave propagation and angular momentum transports, but planetary wave energy changes accompanying tropospheric climate change are also important. <span class="hlt">Stratospheric</span> forcing has a larger impact on the NAO than on the AO, and the angular momentum transport changes associated with it peak in the upper troposphere, affecting all wavenumbers. Tropospheric climate changes influence both the A0 and NAO with effects that extend throughout the troposphere. For both forcings there is often vertical consistency in the sign of the momentum transport changes, obscuring the difference between direct and indirect mechanisms for influencing the surface circulation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016ClDy...46.1397O','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016ClDy...46.1397O"><span id="translatedtitle">Troposphere-<span class="hlt">stratosphere</span> response to large-scale North Atlantic Ocean variability in an atmosphere/ocean coupled model</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Omrani, N.-E.; Bader, Jürgen; Keenlyside, N. S.; Manzini, Elisa</p> <p>2016-03-01</p> <p>The instrumental records indicate that the basin-wide wintertime North Atlantic <span class="hlt">warm</span> conditions are accompanied by a pattern resembling negative North Atlantic oscillation (NAO), and cold conditions with pattern resembling the positive NAO. This relation is well reproduced in a control simulation by the <span class="hlt">stratosphere</span> resolving atmosphere-ocean coupled Max-Planck-Institute Earth System Model (MPI-ESM). Further analyses of the MPI-ESM model simulation shows that the large-scale <span class="hlt">warm</span> North Atlantic conditions are associated with a <span class="hlt">stratospheric</span> precursory signal that propagates down into the troposphere, preceding the wintertime negative NAO. Additional experiments using only the atmospheric component of MPI-ESM (ECHAM6) indicate that these <span class="hlt">stratospheric</span> and tropospheric changes are forced by the <span class="hlt">warm</span> North Atlantic conditions. The basin-wide <span class="hlt">warming</span> excites a wave-induced <span class="hlt">stratospheric</span> vortex weakening, <span class="hlt">stratosphere</span>/troposphere coupling and a high-latitude tropospheric <span class="hlt">warming</span>. The induced high-latitude tropospheric <span class="hlt">warming</span> is associated with reduction of the growth rate of low-level baroclinic waves over the North Atlantic region, contributing to the negative NAO pattern. For the cold North Atlantic conditions, the strengthening of the westerlies in the coupled model is confined to the troposphere and lower <span class="hlt">stratosphere</span>. Comparing the coupled and uncoupled model shows that in the cold phase the tropospheric changes seen in the coupled model are not well reproduced by the standalone atmospheric configuration. Our experiments provide further evidence that North Atlantic Ocean variability (NAV) impacts the coupled <span class="hlt">stratosphere</span>/troposphere system. As NAV has been shown to be predictable on seasonal-to-decadal timescales, these results have important implications for the predictability of the extra-tropical atmospheric circulation on these time-scales.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1981Natur.294..733F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1981Natur.294..733F"><span id="translatedtitle">Halocarbons in the <span class="hlt">stratosphere</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Fabian, P.; Borchers, R.</p> <p>1981-12-01</p> <p>The possible impact of chlorine compounds on the Earth's ozone layer has caused concern. Profiles of the anthropogenic halocarbons F-11 (CFC13) and F-12 (CF2Cl2) have already been measured in the <span class="hlt">stratosphere</span>1-4. Measurements of the vertical distribution of methyl chloride (CH3Cl), the most important natural chlorine-bearing species confirm that chlorine of anthropogenic origin now predominates the <span class="hlt">stratosphere</span>5,6. More halogen radicals are added through decomposition of various other halocarbons, most of them released by man. We report here the first measurements of vertical profiles of F-13 (CF3Cl), F-14 (CF4), F-113 (C2F3Cl3), F-114 (C2F4Cl2), F-115 (C2F5Cl), F-116 (C2F6), and F-13 B(CF3Br) resulting from gas chromatography-mass spectrometer (GC-MS) analysis of air samples collected cryogenically between 10 and 33 km, at 44° N. Some data for F-22 (CHF2C1), methyl bromide (CH3Br) and methyl chloroform (CH3CC13) also presented are subject to confirmation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016cosp...41E1481O&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016cosp...41E1481O&link_type=ABSTRACT"><span id="translatedtitle">ORISON, a <span class="hlt">stratospheric</span> project</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ortiz Moreno, Jose Luis; Mueller, Thomas; Duffard, Rene; Juan Lopez-Moreno, Jose; Wolf, Jürgen; Schindler, Karsten; Graf, Friederike</p> <p>2016-07-01</p> <p>Astronomical research based on satellites is extremely expensive, complex, requires years of development, and the overall difficulties are immense. The ORISON project addresses the feasibility study and the design of a global solution based on platforms on-board <span class="hlt">stratospheric</span> balloons, which allows overcoming the limitations of the Earth's atmosphere, but at a much lower cost and with fewer complications than on satellite platforms. The overall idea is the use of small low-cost <span class="hlt">stratospheric</span> balloons, either individually or as a fleet, equipped with light-weight medium-sized telescopes and other instruments to perform specific tasks on short-duration missions. They could carry different payloads for specific "experiments" too, and should be configurable to some degree to accommodate variable instrumentation. These balloon-based telescopes should be designed to be launched from many sites on Earth, not necessarily from remote sites such as Antarctica or near the North Pole, and at low cost. This project has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement No 690013.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20150007705','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20150007705"><span id="translatedtitle">Effect of Recent Sea Surface Temperature Trends on the Arctic <span class="hlt">Stratospheric</span> Vortex</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Garfinkel, Chaim I.; Oman, Luke; Hurwitz, Margaret</p> <p>2015-01-01</p> <p>The springtime Arctic polar vortex has cooled significantly over the satellite era, with consequences for ozone concentrations in the springtime transition season. The causes of this cooling trend are deduced by using comprehensive chemistry-climate model experiments. Approximately half of the satellite era early springtime cooling trend in the Arctic lower <span class="hlt">stratosphere</span> was caused by changing sea surface temperatures (SSTs). An ensemble of experiments forced only by changing SSTs is compared to an ensemble of experiments in which both the observed SSTs and chemically- and radiatively-active trace species are changing. By comparing the two ensembles, it is shown that <span class="hlt">warming</span> of Indian Ocean, North Pacific, and North Atlantic SSTs, and cooling of the tropical Pacific, have strongly contributed to recent polar <span class="hlt">stratospheric</span> cooling in late winter and early spring, and to a weak polar <span class="hlt">stratospheric</span> <span class="hlt">warming</span> in early winter. When concentrations of ozone-depleting substances and greenhouse gases are fixed, polar ozone concentrations show a small but robust decline due to changing SSTs. Ozone changes are magnified in the presence of changing gas concentrations. The <span class="hlt">stratospheric</span> changes can be understood by examining the tropospheric height and heat flux anomalies generated by the anomalous SSTs. Finally, recent SST changes have contributed to a decrease in the frequency of late winter <span class="hlt">stratospheric</span> sudden <span class="hlt">warmings</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20100031214','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20100031214"><span id="translatedtitle">Response of the Antarctic <span class="hlt">Stratosphere</span> to Two Types of El Nino Events</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Hurwitz, M. M.; Newman, P. A.; Oman, L. D.; Molod, A. M.</p> <p>2010-01-01</p> <p>This study is the first to identify a robust El Nino/Southern Oscillation (ENSO) signal in the Antarctic <span class="hlt">stratosphere</span>. El Nino events are classified as either conventional "cold tongue" events (positive SST anomalies in the Nino 3 region) or "<span class="hlt">warm</span> pool" events (positive SST anomalies in the Nino 4 region). The ERA-40, NCEP and MERRA meteorological reanalyses are used to show that the Southern Hemisphere <span class="hlt">stratosphere</span> responds differently to these two types of El Nino events. Consistent with previous studies, "cold tongue" events do not impact temperatures in the Antarctic <span class="hlt">stratosphere</span>. During "<span class="hlt">warm</span> pool" El Nino events, the poleward extension and increased strength of the South Pacific Convergence Zone (SPCZ) favor an enhancement of planetary wave activity during the SON season. On average, these conditions lead to higher polar <span class="hlt">stratospheric</span> temperatures and a weakening of the Antarctic polar jet in November and December, as compared with neutral ENSO years. The phase of the quasi-biennial oscillation (QBO) modulates the <span class="hlt">stratospheric</span> response to "<span class="hlt">warm</span> pool" El Nino events: the strongest planetary wave driving events are coincident with the easterly phase of the QBO.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2010AGUFMGC22A..09X&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2010AGUFMGC22A..09X&link_type=ABSTRACT"><span id="translatedtitle">Effects of <span class="hlt">Stratospheric</span> Sulfate Geoengineering on Food Supply in China</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Xia, L.; Robock, A.</p> <p>2010-12-01</p> <p>Possible food supply change is one of the most important concerns in the discussion of <span class="hlt">stratospheric</span> geoengineering. In regions with high population density, climate changes such as precipitation reduction spurred by <span class="hlt">stratospheric</span> sulfate injection may cause drought, reduce crop yield, and affect the food supply for hundreds of millions of people. Therefore, as part of the research into the benefits and risks of <span class="hlt">stratospheric</span> geoengineering, it is necessary to fully investigate its effects on the regional climate system and crop yields, which is the goal of this study. In particular, we focus on China, not only because of its high risk to experience severe regional climate change after <span class="hlt">stratospheric</span> geoengineering, but also because of its high vulnerability due to a large share of its population living on agriculture. To examine the effects of climate changes induced by geoengineering on Chinese agriculture, we use the DSSAT and CLICROP agricultural simulation models. We first evaluate these models by forcing them with daily weather data and management practices for the period 1978-2008 for all the provinces in China, and compare the results to observations of the yields of major crops in China (early season paddy, double crop paddy, spring wheat, winter wheat, corn, sorghum and soybean). Overall, there is a strong upward trend in both yield and fertilizer use, but interannual variations can be associated with temperature and precipitation variations. Using climate model simulations with the NASA GISS general circulation model forced by both a standard global <span class="hlt">warming</span> scenario (A1B) and A1B combined with <span class="hlt">stratospheric</span> geoengineering, we then apply scenarios of changes of precipitation and temperature from these runs to examine their effects on Chinese agricultural production. Compared to global <span class="hlt">warming</span> only, the geoengineering runs produced summer precipitation reductions in northeastern China but precipitation increases in the Yangtze River region. Without changes</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015A%26A...580A..89G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015A%26A...580A..89G"><span id="translatedtitle"><span class="hlt">Stratospheric</span> benzene and hydrocarbon aerosols detected in Saturn's auroral regions</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Guerlet, S.; Fouchet, T.; Vinatier, S.; Simon, A. A.; Dartois, E.; Spiga, A.</p> <p>2015-08-01</p> <p>Context. Saturn's polar upper atmosphere exhibits significant auroral activity; however, its impact on <span class="hlt">stratospheric</span> chemistry (i.e. the production of benzene and heavier hydrocarbons) and thermal structure remains poorly documented. Aims: We aim to bring new constraints on the benzene distribution in Saturn's <span class="hlt">stratosphere</span>, to characterize polar aerosols (their vertical distribution, composition, thermal infrared optical properties), and to quantify the aerosols' radiative impact on the thermal structure. Methods: Infrared spectra acquired by the Composite Infrared Spectrometer (CIRS) on board Cassini in limb viewing geometry are analysed to derive benzene column abundances and aerosol opacity profiles over the 3 to 0.1 mbar pressure range. The spectral dependency of the haze opacity is assessed in the ranges 680-900 and 1360-1440 cm-1. Then, a radiative climate model is used to compute equilibrium temperature profiles, with and without haze, given the haze properties derived from CIRS measurements. Results: On Saturn's auroral region (80°S), benzene is found to be slightly enhanced compared to its equatorial and mid-latitude values. This contrasts with the Moses & Greathouse (2005, J. Geophys. Res., 110, 9007) photochemical model, which predicts a benzene abundance 50 times lower at 80°S than at the equator. This advocates for the inclusion of ion-related reactions in Saturn's chemical models. The polar <span class="hlt">stratosphere</span> is also enriched in aerosols, with spectral signatures consistent with vibration modes assigned to aromatic and aliphatic hydrocarbons, and presenting similarities with the signatures observed in Titan's <span class="hlt">stratosphere</span>. The aerosol mass loading at 80°S is estimated to be 1-4 × 10-5 g cm-2, an order of magnitude less than on Jupiter, which is consistent with the order of magnitude weaker auroral power at Saturn. We estimate that this polar haze <span class="hlt">warms</span> the middle <span class="hlt">stratosphere</span> by 6 K in summer and cools the upper <span class="hlt">stratosphere</span> by 5 K in winter. Hence</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20140011364','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20140011364"><span id="translatedtitle">On the Lack of <span class="hlt">Stratospheric</span> Dynamical Variability in Low-top Versions of the CMIP5 Models</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Charlton-Perez, Andrew J.; Baldwin, Mark P.; Birner, Thomas; Black, Robert X.; Butler, Amy H.; Calvo, Natalia; Davis, Nicholas A.; Gerber, Edwin P.; Gillett, Nathan; Hardiman, Steven; Kim, Junsu; Kruger, Kirstin; Lee, Yun-Young; Manzini, Elisa; McDaniel, Brent A.; Polvani, Lorenzo; Reichler, Thomas; Shaw, Tiffany A.; Sigmond, Michael; Son, Seok-Woo; Toohey, Matthew; Wilcox, Laura; Yoden, Shigeo; Christiansen, Bo; Lott, Francois; Shindell, Drew; Yukimoto, Seiji; Watanabe, Shingo</p> <p>2013-01-01</p> <p>We describe the main differences in simulations of <span class="hlt">stratospheric</span> climate and variability by models within the fifth Coupled Model Intercomparison Project (CMIP5) that have a model top above the stratopause and relatively fine <span class="hlt">stratospheric</span> vertical resolution (high-top), and those that have a model top below the stratopause (low-top). Although the simulation of mean <span class="hlt">stratospheric</span> climate by the two model ensembles is similar, the low-top model ensemble has very weak <span class="hlt">stratospheric</span> variability on daily and interannual time scales. The frequency of major sudden <span class="hlt">stratospheric</span> <span class="hlt">warming</span> events is strongly underestimated by the low-top models with less than half the frequency of events observed in the reanalysis data and high-top models. The lack of <span class="hlt">stratospheric</span> variability in the low-top models affects their <span class="hlt">stratosphere</span>-troposphere coupling, resulting in short-lived anomalies in the Northern Annular Mode, which do not produce long-lasting tropospheric impacts, as seen in observations. The lack of <span class="hlt">stratospheric</span> variability, however, does not appear to have any impact on the ability of the low-top models to reproduce past <span class="hlt">stratospheric</span> temperature trends. We find little improvement in the simulation of decadal variability for the high-top models compared to the low-top, which is likely related to the fact that neither ensemble produces a realistic dynamical response to volcanic eruptions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20140010937','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20140010937"><span id="translatedtitle">Modifications of the Quasi-biennial Oscillation by a Geoengineering Perturbation of the <span class="hlt">Stratospheric</span> Aerosol Layer</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Aquila, V.; Garfinkel, C. I.; Newman, P. A.; Oman, L. D.; Waugh, D. W.</p> <p>2014-01-01</p> <p>This paper examines the impact of geoengineering via <span class="hlt">stratospheric</span> sulfate aerosol on the quasi-biennial oscillation (QBO) using the NASA Goddard Earth Observing System (GEOS-5) Chemistry Climate Model. We performed four 30-year simulations with a continuous injection of sulfur dioxide on the equator at 0 degree longitude. The four simulations differ by the amount of sulfur dioxide injected (5Tg per year and 2.5 Tg per year) and the altitude of the injection (16km-25km and 22km-25km). We find that such an injection dramatically alters the quasi-biennial oscillation, prolonging the phase of easterly shear with respect to the control simulation. In the case of maximum perturbation, i.e. highest <span class="hlt">stratospheric</span> aerosol burden, the lower tropical <span class="hlt">stratosphere</span> is locked into a permanent westerly QBO phase. This locked QBO westerly phase is caused by the increased aerosol heating and associated <span class="hlt">warming</span> in the tropical lower <span class="hlt">stratosphere</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20100004813&hterms=Ozone+layer&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3D%2528Ozone%2Blayer%2529','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20100004813&hterms=Ozone+layer&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3D%2528Ozone%2Blayer%2529"><span id="translatedtitle">The Impact of Geoengineering Aerosols on <span class="hlt">Stratospheric</span> Temperature and Ozone</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Heckendorn, P.; Weisenstein, D.; Fueglistaler, S.; Luo, B. P.; Rozanov, E.; Schraner, M.; Peter, T.; Thomason, L. W.</p> <p>2009-01-01</p> <p>Anthropogenic greenhouse gas emissions are <span class="hlt">warming</span> the global climate at an unprecedented rate. Significant emission reductions will be required soon to avoid a rapid temperature rise. As a potential interim measure to avoid extreme temperature increase, it has been suggested that Earth's albedo be increased by artificially enhancing <span class="hlt">stratospheric</span> sulfate aerosols. We use a 3D chemistry climate model, fed by aerosol size distributions from a zonal mean aerosol model, to simulate continuous injection of 1-10 Mt/a into the lower tropical <span class="hlt">stratosphere</span>. In contrast to the case for all previous work, the particles are predicted to grow to larger sizes than are observed after volcanic eruptions. The reason is the continuous supply of sulfuric acid and hence freshly formed small aerosol particles, which enhance the formation of large aerosol particles by coagulation and, to a lesser extent, by condensation. Owing to their large size, these particles have a reduced albedo. Furthermore, their sedimentation results in a non-linear relationship between <span class="hlt">stratospheric</span> aerosol burden and annual injection, leading to a reduction of the targeted cooling. More importantly, the sedimenting particles heat the tropical cold point tropopause and, hence, the <span class="hlt">stratospheric</span> entry mixing ratio of H2O increases. Therefore, geoengineering by means of sulfate aerosols is predicted to accelerate the hydroxyl catalyzed ozone destruction cycles and cause a significant depletion of the ozone layer even though future halogen concentrations will be significantly reduced.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20110014198&hterms=Ozone+layer&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3D%2528Ozone%2Blayer%2529','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20110014198&hterms=Ozone+layer&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3D%2528Ozone%2Blayer%2529"><span id="translatedtitle">The Impact of Geoengineering Aerosols on <span class="hlt">Stratospheric</span> Temperature and Ozone</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Heckendorn, P.; Weisenstein, D.; Fueglistaler, S.; Luo, B. P.; Rozanov, E.; Schraner, M.; Thomason, L. W.; Peter, T.</p> <p>2011-01-01</p> <p>Anthropogenic greenhouse gas emissions are <span class="hlt">warming</span> the global climate at an unprecedented rate. Significant emission reductions will be required soon to avoid a rapid temperature rise. As a potential interim measure to avoid extreme temperature increase, it has been suggested that Earth's albedo be increased by artificially enhancing <span class="hlt">stratospheric</span> sulfate aerosols. We use a 3D chemistry climate model, fed by aerosol size distributions from a zonal mean aerosol model. to simulate continuous injection of 1-10 Mt/a into the lower tropical <span class="hlt">stratosphere</span>. In contrast to the case for all previous work, the particles are predicted to grow to larger sizes than are observed after volcanic eruptions. The reason is the continuous supply of sulfuric acid and hence freshly formed small aerosol particles, which enhance the formation of large aerosol particles by coagulation and, to a lesser extent, by condensation. Owing to their large size, these particles have a reduced albedo. Furthermore, their sedimentation results in a non-linear relationship between <span class="hlt">stratospheric</span> aerosol burden and annual injection, leading to a reduction of the targeted cooling. More importantly, the sedimenting particles heat the tropical cold point tropopause and, hence, the <span class="hlt">stratospheric</span> entry mixing ratio of H2O increases. Therefore, geoengineering by means of sulfate aerosols is predicted to accelerate the hydroxyl catalyzed ozone destruction cycles and cause a significant depletion of the ozone layer even though future halogen concentrations will he significantly reduced.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010AGUFMGC31A0860M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010AGUFMGC31A0860M"><span id="translatedtitle">Arctic climate response to geoengineering with <span class="hlt">stratospheric</span> sulfate aerosols</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>McCusker, K. E.; Battisti, D. S.; Bitz, C. M.</p> <p>2010-12-01</p> <p>Recent <span class="hlt">warming</span> and record summer sea-ice area minimums have spurred expressions of concern for arctic ecosystems, permafrost, and polar bear populations, among other things. Geoengineering by <span class="hlt">stratospheric</span> sulfate aerosol injections to deliberately cancel the anthropogenic temperature rise has been put forth as a possible solution to restoring Arctic (and global) climate to modern conditions. However, climate is particularly sensitive in the northern high latitudes, responding easily to radiative forcing changes. To that end, we explore the extent to which tropical injections of <span class="hlt">stratospheric</span> sulfate aerosol can accomplish regional cancellation in the Arctic. We use the Community Climate System Model version 3 global climate model to execute simulations with combinations of doubled CO2 and imposed <span class="hlt">stratospheric</span> sulfate burdens to investigate the effects on high latitude climate. We further explore the sensitivity of the polar climate to ocean dynamics by running a suite of simulations with and without ocean dynamics, transiently and to equilibrium respectively. We find that, although annual, global mean temperature cancellation is accomplished, there is over-cooling on land in Arctic summer, but residual <span class="hlt">warming</span> in Arctic winter, which is largely due to atmospheric circulation changes. Furthermore, the spatial extent of these features and their concurrent impacts on sea-ice properties are modified by the inclusion of ocean dynamical feedbacks.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2004JAtS...61..161H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2004JAtS...61..161H"><span id="translatedtitle"><span class="hlt">Stratospheric</span> Tracer Spectra.</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Haynes, P. H.; Vanneste, J.</p> <p>2004-01-01</p> <p>The combined effects of advection and diffusion on the equilibrium spatial structure of a tracer whose spatial variation is maintained by a large-scale forcing are considered. Motivated by the lower <span class="hlt">stratosphere</span>, the flow is taken to be large-scale, time-dependent, and purely horizontal but varying in the vertical, with the vertical shear much larger than horizontal velocity gradients. As a result, the ratio α between horizontal and vertical tracer scales is large. (For the lower <span class="hlt">stratospheric</span> surf zone α has been shown to be about 250.) The diffusion parameterizes the mixing effects of small-scale processes.The three space dimensions and the large range between the forcing scale and the diffusive scale mean that direct numerical simulation would be prohibitively expensive for this problem. Instead, an ensemble approach is used that takes advantage of the separation between the large scale of the flow and the small scale of the tracer distribution. This approach, which has previously been used in theoretical investigations of two-dimensional flows, provides an efficient technique to derive statistical properties of the tracer distributions such as horizontal-wavenumber spectrum.First, the authors consider random-strain models in which the velocity gradient experienced by a fluid parcel is modeled by a random process. The results show the expected k-1 Batchelor spectrum at large scales, with a deviation from this form at a scale that is larger by a factor α than the diffusive scale found in the absence of vertical shear. This effect may be crudely captured by replacing the diffusivity κ by an “=uivalent diffusivity” α2κ, but the diffusive dissipation is then substantially overestimated, and the spectrum at large k is too steep. This may be attributed to the failure of the equivalent diffusivity to capture the variability of the vertical shear.The technique is then applied to lower-<span class="hlt">stratospheric</span> velocity fields. For realistic values of the diffusivity κ</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EGUGA..1817925O','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EGUGA..1817925O"><span id="translatedtitle">Dynamics of the future anthropogenic climate change in the Northern Hemisphere coupled <span class="hlt">stratosphere</span>/troposphere system.</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Omrani, Nour-Eddine</p> <p>2016-04-01</p> <p>There is increasing evidence that the response to future anthropogenic climate changes in Northern hemisphere is characterized by weakening of high-latitude westerlies in the coupled <span class="hlt">stratosphere</span>/troposphere-system and strengthening of mid-latitude tropospheric eddy-driven jet with strong impact on large-scale precipitation. Here we show using different model experiments and wave geometry diagnostics that the overall dynamics of this response can be understood in the framework of two competing atmospheric bridges. One bridge is located in the <span class="hlt">stratosphere</span> and connect the tropical Sea Surface Temperature (SST) with the coupled high-latitude <span class="hlt">stratosphere</span>/troposphere system through changes in the upper flank of subtropical jet and downward <span class="hlt">stratosphere</span>/troposphere dynamical coupling. This bridge is responsible for the weakening of the westerlies in high latitude <span class="hlt">stratosphere</span>/troposphere system. The second bridge is in the troposphere and connects the tropical ocean <span class="hlt">warming</span> with the extra-tropics trough changes in the static stability. This bridge is responsible for the wave-induced strengthening of the tropospheric eddy-driven jet. It is shown that the large-scale precipitation response in mid-to-high latitudes results mainly from the dynamical adjustment to wave-driven changes in the tropospheric meridional overturning circulation. The competing interaction between the <span class="hlt">stratospheric</span> and tropospheric pathway constitutes another aspect of <span class="hlt">stratosphere</span>/troposphere dynamical coupling. Her we will show how that such coupling can help understanding model discrepancies in the Northern Hemisphere future climate change.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19880042145&hterms=Nitrous+oxide+chemistry&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3DNitrous%2Boxide%2Bchemistry','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19880042145&hterms=Nitrous+oxide+chemistry&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3DNitrous%2Boxide%2Bchemistry"><span id="translatedtitle">Chemistry of the Antarctic <span class="hlt">stratosphere</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Mcelroy, Michael B.; Salawitch, Ross J.; Wofsy, Steven C.</p> <p>1988-01-01</p> <p>Interferometric measurements of HCl, ClNO3, HNO3, NO2, and NO obtained over the Antarctic in 1986 are used to model the chemistry of the atmosphere in the region of the Ozone Hole. The low abundance noted in <span class="hlt">stratospheric</span> HCl is attributed to incorporation of HCl in polar <span class="hlt">stratospheric</span> clouds and subsequent reaction of HCl with ClNO3. The results point to a net loss of HNO3 from the <span class="hlt">stratosphere</span> and to the suppression of the abundance of odd nitrogen at high altitudes in the vortex. O3 loss is suggested to be due to the catalytic influence of halogen radicals.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19950054948&hterms=love&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3Dlove','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19950054948&hterms=love&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3Dlove"><span id="translatedtitle">Densities of <span class="hlt">stratospheric</span> micrometeorites</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Love, Stanley G.; Joswiak, David J.; Brownlee, Donald E.</p> <p>1994-01-01</p> <p>We have measured the densities of roughly 150 5- to 15-microns interplanetary dust particles (IDPs) harvested in the <span class="hlt">stratosphere</span>. Care was taken to minimize selection bias in the sample population. Masses were determined using an absolute X-ray analysis technique with a transmission electron microscope, and volumes were found using scanning electron microscope imagery. Unmelted chondritic particles have densities ranging between 0.3 and 6.2 g/cu cm, averaging 2.0 g/cu cm. The low medium densities indicates appreciable porosity, suggesting primitive, uncompacted parent bodies for these particles. Porosities greater than 70% are rare. IDPs with densities above 3.5 g/cu cm usually contain large sulfide grains. We find no evidence of bimodality in the unmelted particle density distribution. Chondritic spherules (melted particles) have densities near 3.4 g/cu cm, consistent with previous results for stony spheurles culled from deep-sea sediments.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19810024205','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19810024205"><span id="translatedtitle"><span class="hlt">Stratospheric</span> CCN sampling program</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Rogers, C. F.</p> <p>1981-01-01</p> <p>When Mt. St. Helens produced several major eruptions in the late spring of 1980, there was a strong interest in the characterization of the cloud condensation nuclei (CCN) activity of the material that was injected into the troposphere and <span class="hlt">stratosphere</span>. The scientific value of CCN measurements is two fold: CCN counts may be directly applied to calculations of the interaction of the aerosol (enlargement) at atmospherically-realistic relative humidities or supersaturations; and if the chemical constituency of the aerosol can be assumed, the number-versus-critical supersaturation spectrum may be converted into a dry aerosol size spectrum covering a size region not readily measured by other methods. The sampling method is described along with the instrumentation used in the experiments.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li class="active"><span>12</span></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_12 --> <div id="page_13" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li class="active"><span>13</span></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="241"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AGUFM.A23A0174S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AGUFM.A23A0174S"><span id="translatedtitle">Numerical simulation of the gravitational separation in the <span class="hlt">stratosphere</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sugawara, S.; Ishidoya, S.; Morimoto, S.; Aoki, S.; Nakazawa, T.; Honda, H.; Murayama, S.</p> <p>2012-12-01</p> <p>It has been shown that the gravitational separation effect in the <span class="hlt">stratosphere</span> can be observable from the measurements of N2, O2 and Ar isotopic ratios and Ar/N2 ratio. The gravitational separation has a possibility to be a new tracer of <span class="hlt">stratospheric</span> circulation. In this study, theoretical simulations were performed to validate an existence of the gravitational separation in the <span class="hlt">stratosphere</span>, as well as to evaluate the magnitude of the isotopic discrimination of the atmospheric major components driven by molecular diffusion process. The 2-dimensional model of the middle atmosphere (SOCRATES) developed by NCAR was used to evaluate the gravitational separation in the <span class="hlt">stratosphere</span>. This model originally includes mass transport processes caused by molecular diffusion to take into account only above the mesosphere, since the molecular diffusion effect has been thought to be negligibly small in the <span class="hlt">stratosphere</span>, compared with the eddy diffusion effect. In this study, we simply lowered its vertical domain to the tropopause for the calculation of molecular diffusion. We assumed the thermal diffusion factor to be zero, since the thermal diffusion effect would be of no importance in the <span class="hlt">stratosphere</span>. We simulated the height-latitude distributions of 44CO2 and 45CO2 concentrations, and then calculated the isotopic ratio as a δ value (in per meg). As a result, it is concluded that the magnitude of the gravitational separation in the <span class="hlt">stratosphere</span> will be significant enough to be detected by recent isotopic measurements. To examine how the CO2 age and the δ value are influenced by changes in the <span class="hlt">stratospheric</span> circulation, we made numerical simulations under the condition that the meridional mass transport is arbitrarily accelerated on the supposition that the Brewer-Dobson circulation (BDC) is enhanced due to global <span class="hlt">warming</span>. The relationships between the two variables under the enhanced-BDC condition are clearly different from those under the normal condition, indicating that</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19960016947','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19960016947"><span id="translatedtitle">NDSC and JPL <span class="hlt">stratospheric</span> lidars</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>McDermid, I. Stuart</p> <p>1995-01-01</p> <p>The Network for the Detection of <span class="hlt">Stratospheric</span> Change is an international cooperation providing a set of high-quality, remote-sensing instruments at observing stations around the globe. A brief description of the NDSC and its goals is presented. Lidar has been selected as the NDSC instrument for measurements of <span class="hlt">stratospheric</span> profiles of ozone, temperature, and aerosol. The Jet Propulsion Laboratory has developed and implemented two <span class="hlt">stratospheric</span> lidar systems for NDSC. These are located at Table Mountain, California, and at Mauna Loa, Hawaii. These systems, which utilize differential absorption lidar, Rayleigh lidar, raman lidar, and backscatter lidar, to measure ozone, temperature, and aerosol profiles in the <span class="hlt">stratosphere</span> are briefly described. Examples of results obtained for both long-term and individual profiles are presented.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015ESASP.730..641L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015ESASP.730..641L"><span id="translatedtitle">Project Together into the <span class="hlt">Stratosphere</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lenza, L.; Kapus, J.; Zavodsky, O.; Erdziak, J.; Zitka, J.; Kizek, R.; Peciva, T.</p> <p>2015-09-01</p> <p><span class="hlt">Stratosphere</span> is easily accessible near-space environment with potential to be extensively used for experiments and interdisciplinary research requiring harsh conditions difficult to simulate on Earth. But it turns out that it has other properties as well. It can also connect people. In this case young people, students and scientists from both sides of former Czechosloyak border, which led to project called "Together into <span class="hlt">stratosphere</span>". It is a cross-border collaboration project between Valasské Mezirici Observatory in Czech Republic and Slovak Organization for Space Activities in Slovakia, which started in 2013. By sending probes on meteorological balloons to <span class="hlt">stratosphere</span>, members of this project already executed multiple experiments, which involved biological experiments, measurements of cosmic radiation, technology experiments like tests of photovoltaic panels, JR radiation measurements, R-wave measurements, tests of picosatellite, communication between ground station and <span class="hlt">stratospheric</span> platform and tests of GPS.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015PrAeS..75...26W&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015PrAeS..75...26W&link_type=ABSTRACT"><span id="translatedtitle">Thermal modeling of <span class="hlt">stratospheric</span> airships</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wu, Jiangtao; Fang, Xiande; Wang, Zhenguo; Hou, Zhongxi; Ma, Zhenyu; Zhang, Helei; Dai, Qiumin; Xu, Yu</p> <p>2015-05-01</p> <p>The interest in <span class="hlt">stratospheric</span> airships has increased and great progress has been achieved since the late 1990s due to the advancement of modern techniques and the wide range of application demands in military, commercial, and scientific fields. Thermal issues are challenging for <span class="hlt">stratospheric</span> airships, while there is no systematic review on this aspect found yet. This paper presents a comprehensive literature review on thermal issues of <span class="hlt">stratospheric</span> airships. The main challenges of thermal issues on <span class="hlt">stratospheric</span> airships are analyzed. The research activities and results on the main thermal issues are surveyed, including solar radiation models, environmental longwave radiation models, external convective heat transfer, and internal convective heat transfer. Based on the systematic review, guides for thermal model selections are provided, and topics worthy of attention for future research are suggested.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/6702538','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/6702538"><span id="translatedtitle">Greenhouse gases in the <span class="hlt">stratosphere</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Wenyi Zhong; Haigh, J.D. ); Pyle, J.A. )</p> <p>1993-02-20</p> <p>The potential radiative forcing in the <span class="hlt">stratosphere</span> of changing concentrations of ozone, methane, nitrous oxide and chlorofluorocarbons 11 and 12 is assessed. Significant changes in heating rate in the lower <span class="hlt">stratosphere</span> are found. The response of a fully interactive radiative-photochemical-dynamical two-dimensional model to such changes in gaseous concentrations is investigated. The inclusion of CH[sub 4], N[sub 2]O and the CFC in the radiation scheme causes a small (1 K) decrease in temperature throughout the <span class="hlt">stratosphere</span> after 50 model years with a resulting increase in ozone column up to 1% in summer high latitudes. An experiment in which lower <span class="hlt">stratospheric</span> ozone concentrations were forcibly reduced in line with recent satellite observations results in significant (several degrees) temperature decrease in this region. Such decreases may be very significant in maintaining polar ozone loss. 20 refs., 12 figs., 2 tabs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JGRD..12011438Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JGRD..12011438Y"><span id="translatedtitle">Signal of central Pacific El Niño in the Southern Hemispheric <span class="hlt">stratosphere</span> during austral spring</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yang, Chengyun; Li, Tao; Dou, Xiankang; Xue, Xianghui</p> <p>2015-11-01</p> <p>Using ERA-Interim and Modern-Era Retrospective Analysis for Research and Applications reanalysis data sets, we investigated the effects of the central Pacific (CP) El Niño on the Southern Hemispheric (SH) <span class="hlt">stratosphere</span> particularly during the austral spring. SH <span class="hlt">stratosphere</span> <span class="hlt">warming</span> is at a maximum in September rather than in November and December, as suggested by previous studies. SH <span class="hlt">stratospheric</span> temperature anomalies become significant beginning in July and reach a peak of approximately 4 K in September, reflecting a weakened SH vortex and a strengthened SH <span class="hlt">stratospheric</span> Brewer-Dobson circulation. The anomalous Eliassen-Palm flux and its divergence in the SH midlatitudes are most significantly enhanced in August, leading to the SH maximum <span class="hlt">stratospheric</span> temperature anomalies approximately 1 month later. In the middle latitudes of the SH, the poleward and upward propagation of enhanced planetary waves (PWs) during the austral winter (July-September) causes anomalous SH polar <span class="hlt">warming</span> and tropical cooling in the <span class="hlt">stratosphere</span>. The wave number 1 (WN1) pattern is responsible for PW anomalies in August, whereas the WN2 pattern is responsible for those in September. Eddy heat flux during CP El Niño is also anomalously enhanced in extratropical SH <span class="hlt">stratosphere</span> in both August and September and subsequently weaken during the following months.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014cosp...40E3411T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014cosp...40E3411T"><span id="translatedtitle">Universal <span class="hlt">stratospheric</span> balloon gradiometer</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tsvetkov, Yury; Filippov, Sergey; Brekhov, Oleg; Nikolaev, Nikolay</p> <p></p> <p>The study of the interior structure of the Earth and laws of its evolution is one of the most difficult problems of natural science. Among the geophysical fields the anomaly magnetic field is one of the most informational in questions of the Earth’s crust structure. Many important parameters of an environment are expedient for measuring at lower altitudes, than satellite ones. So, one of the alternatives is <span class="hlt">stratospheric</span> balloon survey. The balloon flight altitudes cover the range from 20 to 50 km. At such altitudes there are steady zone air flows due to which the balloon flight trajectories can be of any direction, including round-the-world (round-the-pole). For investigation of Earth's magnetic field one of the examples of such sounding system have been designed, developed and maintained at IZMIRAN and MAI during already about 25 years. This system consists of three instrumental containers uniformly placed along a vertical 6 km line. Up today this set has been used only for geomagnetic purposes. So we describe this system on example of the measuring of the geomagnetic field gradient. System allows measuring a module and vertical gradient of the geomagnetic field along the whole flight trajectory and so one’s name is - <span class="hlt">stratospheric</span> balloon magnetic gradiometer (SMBG). The GPS-receivers, located in each instrumental container, fix the flight coordinates to within several tens meters. Process of SBMG deployment, feature of the exit of rope from the magazine at the moment of balloon launching has been studied. Used magazine is cellular type. The hodograph of the measuring base of SBMG and the technique of correction of the deviations of the measuring base from the vertical line (introduction of the amendments for the deviation) during the flight have been investigated. It is shown that estimation of the normal level of values of the vertical gradient of the geomagnetic field is determined by the accuracy of determining the length of the measuring base SBMG</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009APS..APR.Q7002R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009APS..APR.Q7002R"><span id="translatedtitle">The Many Problems with Geoengineering Using <span class="hlt">Stratospheric</span> Aerosols</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Robock, Alan</p> <p>2009-05-01</p> <p>In response to the global <span class="hlt">warming</span> problem, there has been a recent renewed call for geoengineering ``solutions'' involving injecting particles into the <span class="hlt">stratosphere</span> or blocking sunlight with satellites between the Sun and Earth. While volcanic eruptions have been suggested as innocuous examples of <span class="hlt">stratospheric</span> aerosols cooling the planet, the volcano analog actually argues against geoengineering because of ozone depletion and regional hydrologic and temperature responses. In this talk, I consider the suggestion to create an artificial <span class="hlt">stratospheric</span> aerosol layer. No systems to conduct geoengineering now exist, but a comparison of different proposed <span class="hlt">stratospheric</span> injection schemes, airplanes, balloons, artillery, and a space elevator, shows that using airplanes would not be that expensive. We simulated the climate response to both tropical and Arctic <span class="hlt">stratospheric</span> injection of sulfate aerosol precursors using a comprehensive atmosphere-ocean general circulation model, the National Aeronautics and Space Administration Goddard Institute for Space Studies ModelE. We simulated the injection of SO2 and the model converts it to sulfate aerosols, transports them and removes them through dry and wet deposition, and calculates the climate response to the radiative forcing from the aerosols. We conducted simulations of future climate with the Intergovernmental Panel on Climate Change A1B business-as-usual scenario both with and without geoengineering, and compare the results. We found that if there were a way to continuously inject SO2 into the lower <span class="hlt">stratosphere</span>, it would produce global cooling. Acid deposition from the sulfate would not be enough to disturb most ecosystems. Tropical SO2 injection would produce sustained cooling over most of the world, with more cooling over continents. Arctic SO2 injection would not just cool the Arctic. But both tropical and Arctic SO2 injection would disrupt the Asian and African summer monsoons, reducing precipitation to the food supply</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010EGUGA..1213034G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010EGUGA..1213034G"><span id="translatedtitle">The relationship between the polar vortex and ozone in the boreal <span class="hlt">stratosphere</span> from ERA-40 reanalysis</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>González-Merino, Beatriz; Serrano, Encarna</p> <p>2010-05-01</p> <p>The relation between the ozone and the polar vortex in the <span class="hlt">stratosphere</span> has an outstanding role in climate studios, and also a large repercussion in the improvement of the climate models. This importance is due to the combination of two reasons: the key role of the <span class="hlt">stratospheric</span> ozone in the Earth climate due to its radiative properties, and that the most important dynamic activity in the high-latitude <span class="hlt">stratosphere</span> is associated with the polar vortex (present during the whole winter and part of the spring). This work focuses on the spring months, a transitional period in the <span class="hlt">stratospheric</span> circulation between the winter westerlies (the <span class="hlt">stratospheric</span> polar vortex, SPV, is completely developed) and summer easterlies (SPV has already disappeared). This breakdown of the SPV is known as the <span class="hlt">Stratospheric</span> Final <span class="hlt">Warming</span>, SFW. Using ERA-40 data, currently the longest-period reanalysis (1979-2002) with a sufficiently realistic representation of the <span class="hlt">stratosphere</span> circulation, we analyze different aspects about the relation between the ozone concentration and the intensity of polar vortex in the boreal <span class="hlt">stratosphere</span> during the springtime. Among other results, we see that the 24-yr mean evolution of the <span class="hlt">stratospheric</span> ozone, averaged over the polar region (60°N-80°N), exhibits a slow increase along March followed by a progressive decrease during April and May. The interannual variability of the monthly mean of zonal wind and ozone mixing ratio at 50 hPa in the analyzed polar region decreases gradually along the season as well. When analyzing the springtime <span class="hlt">stratospheric</span> preconditioning, we found that almost all the <span class="hlt">warm</span> Februaries are not associated with low ozone content and strong SPV at the beginning of March; and that none cold February was followed by a weak SPV in the first third of March. Also, the <span class="hlt">stratospheric</span> conditions around the SFW occurrence have been studied. It is seen that the 50-hPa ozone over the polar region is nearly constant prior to the SFW, while it gets</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20000074253&hterms=Datasets&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3DDatasets','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20000074253&hterms=Datasets&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3DDatasets"><span id="translatedtitle">Troposphere-<span class="hlt">Stratosphere</span> Connections in Recent Northern Winters in NASA GEOS Assimilated Datasets</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Pawson, Steven</p> <p>2000-01-01</p> <p>The northern winter <span class="hlt">stratosphere</span> displays a wide range of interannual variability, much of which is believed to result from the response to the damping of upward-propagating waves. However, there is considerable (growing) evidence that the <span class="hlt">stratospheric</span> state can also impact the tropospheric circulation. This issue will be examined using datasets generated in the Data Assimilation Office (DAO) at NASA's Goddard Space Flight Center. Just as the tropospheric circulation in each of these years was dominated by differing synoptic-scale structures, the <span class="hlt">stratospheric</span> polar vortex also displayed different evolutions. The two extremes are the winter 1998/1999, when the <span class="hlt">stratosphere</span> underwent a series of <span class="hlt">warming</span> events (including two major <span class="hlt">warmings</span>), and the winter 1999/2000, which was dominated by a persistent, cold polar vortex, often distorted by a dominant blocking pattern in the troposphere. This study will examine several operational and research-level versions of the DAO's systems. The 70-level-TRMM-system with a resolution of 2-by-2.5 degrees and the 48-level, 1-by-l-degree resolution ''Terra'' system were operational in 1998/1999 and 1999/2000, respectively. Research versions of the system used a 48-level, 2-by-2.5-degree configuration, which facilitates studies of the impact of vertical resolution. The study includes checks against independent datasets and error analyses, as well as the main issue of troposphere-<span class="hlt">stratosphere</span> interactions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2003AIPC..664..523O','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2003AIPC..664..523O"><span id="translatedtitle">Beam Driven <span class="hlt">Stratospheric</span> Airship</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Onda, Masahiko</p> <p>2003-05-01</p> <p>Even though satellite, balloons and aircraft have served admirably as aerospace platforms for remote sensing and telecommunication, requirements for a new kind of platforms - an easily modifiable, sub-orbital platform - have been widely identified. The High-Altitude Long-Range Observational Platform(HALROP) was at first conceptualized as a solar power driven unmanned LTA (Lighter-Than-Air) vehicle or an airship to maintain a station-keeping position in the lower <span class="hlt">stratosphere</span> for long-durations and to carry out missions such as high-resolution monitoring and high-speed informational relays. Nevertheless solar power is not available in winter seasons in the high-latitudinal regions. Therefore, alternative power sources are necessary and the candidates are surface-to-air transmission of microwave energy and high-power laser beams. The author introduces a wireless power transmission test by microwave carried in 1995 in Kobe, Japan, and then, discusses possibilities of using laser beam for powering such LTA platforms.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/6488246','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/6488246"><span id="translatedtitle">Superpressure <span class="hlt">stratospheric</span> vehicle</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Chocol, C.; Robinson, W.; Epley, L.</p> <p>1990-09-15</p> <p>Our need for wide-band global communications, earth imaging and sensing, atmospheric measurements and military reconnaissance is extensive, but growing dependence on space-based systems raises concerns about vulnerability. Military commanders require space assets that are more accessible and under local control. As a result, a robust and low cost access to space-like capability has become a national priority. Free floating buoyant vehicles in the middle <span class="hlt">stratosphere</span> can provide the kind of cost effective access to space-like capability needed for a variety of missions. These vehicles are inexpensive, invisible, and easily launched. Developments in payload electronics, atmospheric modeling, and materials combined with improving communications and navigation infrastructure are making balloon-borne concepts more attractive. The important milestone accomplished by this project was the planned test flight over the continental United States. This document is specifically intended to review the technology development and preparations leading up to the test flight. Although the test flight experienced a payload failure just before entering its assent altitude, significant data were gathered. The results of the test flight are presented here. Important factors included in this report include quality assurance testing of the balloon, payload definition and characteristics, systems integration, preflight testing procedures, range operations, data collection, and post-flight analysis. 41 figs., 5 tabs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19930001903','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19930001903"><span id="translatedtitle"><span class="hlt">Stratospheric</span> processes: Observations and interpretation</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Brune, William H.; Cox, R. Anthony; Turco, Richard; Brasseur, Guy P.; Matthews, W. Andrew; Zhou, Xiuji; Douglass, Anne; Zander, Rudi J.; Prendez, Margarita; Rodriguez, Jose M.</p> <p>1991-01-01</p> <p>Explaining the observed ozone trends discussed in an earlier update and predicting future trends requires an understanding of the <span class="hlt">stratospheric</span> processes that affect ozone. <span class="hlt">Stratospheric</span> processes occur on both large and small spatial scales and over both long and short periods of time. Because these diverse processes interact with each other, only in rare cases can individual processes be studied by direct observation. Generally the cause and effect relationships for ozone changes were established by comparisons between observations and model simulations. Increasingly, these comparisons rely on the developing, observed relationships among trace gases and dynamical quantities to initialize and constrain the simulations. The goal of this discussion of <span class="hlt">stratospheric</span> processes is to describe the causes for the observed ozone trends as they are currently understood. At present, we understand with considerable confidence the <span class="hlt">stratospheric</span> processes responsible for the Antarctic ozone hole but are only beginning to understand the causes of the ozone trends at middle latitudes. Even though the causes of the ozone trends at middle latitudes were not clearly determined, it is likely that they, just as those over Antarctica, involved chlorine and bromine chemistry that was enhanced by heterogeneous processes. This discussion generally presents only an update of the observations that have occurred for <span class="hlt">stratospheric</span> processes since the last assessment (World Meteorological Organization (WMO), 1990), and is not a complete review of all the new information about <span class="hlt">stratospheric</span> processes. It begins with an update of the previous assessment of polar <span class="hlt">stratospheres</span> (WMO, 1990), followed by a discussion on the possible causes for the ozone trends at middle latitudes and on the effects of bromine and of volcanoes.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015EGUGA..17.9459K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015EGUGA..17.9459K"><span id="translatedtitle"><span class="hlt">Stratospheric</span> carbonyl sulfide (OCS) burden</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kloss, Corinna; Walker, Kaley A.; Deshler, Terry; von Hobe, Marc</p> <p>2015-04-01</p> <p>An estimation of the global <span class="hlt">stratospheric</span> burden of carbonyl sulfide (OCS) calculated using satellite based measurements from the Atmospheric Chemistry Experiment - Fourier Transform Spectrometer (ACE-FTS) will be presented. OCS is the most abundant sulfur containing gas in the atmosphere in the absence of volcanic eruptions. With a long lifetime of 2-6 years it reaches the <span class="hlt">stratosphere</span> where it is photolyzed and the sulfur oxidized and condensed to aerosols, contributing to the <span class="hlt">stratospheric</span> aerosol layer. The aerosol layer is the one factor of the middle-atmosphere with a direct impact on the Earth's climate by scattering incoming solar radiation back to space. Therefore it is crucial to understand and estimate the different processes and abundances of the species contributing to the aerosol layer. However, the exact amount of OCS in the <span class="hlt">stratosphere</span> has not been quantified yet. A study on the OCS mixing ratio distribution based on ACE-FTS data has already been made by Barkley et al. (2008), also giving an estimation for the total atmospheric OCS mass. ACE-FTS is an infrared solar occultation spectrometer providing high- resolution profile observations since 2004. In the scope of this work the focus lies on the <span class="hlt">stratospheric</span> OCS burden, calculated by integrating the ACE profiles. A global overview on the <span class="hlt">stratospheric</span> OCS amount in the past and present based on the ACE data as well as a look at regional and seasonal variability will be given. Furthermore, the results of this work will be useful for further studies on OCS fluxes and lifetimes, and in quantifying the contribution of OCS to the global <span class="hlt">stratospheric</span> sulfur burden. Barkley et al., 2008, Geophys. Res. Lett., 35, L14810.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010EGUGA..1210057P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010EGUGA..1210057P"><span id="translatedtitle">STRAPOLETE : Studying summer polar <span class="hlt">stratosphere</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Payan, Sebastien</p> <p>2010-05-01</p> <p>The polar <span class="hlt">stratosphere</span> in the summertime remains largely unexplored. Dynamical conditions are characterized by large scale transport and mixing between air masses of higher and lower latitude origins. Understanding these exchanges is crucial since they have a large impact on the distribution of trace gases and aerosols at polar latitudes, and thus on the <span class="hlt">stratospheric</span> ozone budget. Ozone change affects the radiative balance, the coupling between troposphere and <span class="hlt">stratosphere</span>, and therefore the climate. In the framework of the International Polar Year, the STRAPOLETE project starts on January 2009. It is associated with a successful balloon borne campaign which took place close to Kiruna (Sweeden) from 2 August 2009 to 12 September 2009 with eight balloon flights. During this campaign the main characteristics of the summertime arctic <span class="hlt">stratosphere</span> have been captured. The data set obtained using UV-visible and infrared instruments, remote and in situ sensing embarked spectrometers provided detailed information on vertical distributions of more than fifteen chemical tracers and reactive species from the upper troposphere to the middle <span class="hlt">stratosphere</span>. A number of in situ optical aerosol counters, a UV-visible remote spectrometer for the aerosol extinction and a photopolarimeter provided information on the nature and size distribution of the <span class="hlt">stratospheric</span> aerosols. These balloon measurements with high precision and high vertical resolution are relevant to qualify the dynamical processes occurring in this region during summertime, the aerosols variability, the bromine abundance and establish a reference state of the polar summer <span class="hlt">stratosphere</span>. The data set is completed by satellite data offering large spatial coverage of the region of interest. Data analysis is made using relevant dynamical (trajectory calculations, contour advection model) and chemistry-transport models (CTM) to highlight major mechanisms that control the distribution of tracers, aerosols and bromine. An</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/166245','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/166245"><span id="translatedtitle">Modeled impacts of <span class="hlt">stratospheric</span> ozone and water vapor perturbations with implications for high-speed civil transport aircraft</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Rind, D.; Lonergan, P.</p> <p>1995-04-20</p> <p>Ozone and water vapor perturbations are explored in a series of experiments with the Goddard Institute for Space Studies climate/middle atmosphere model. Large perturbations, and realistic perturbations, to <span class="hlt">stratospheric</span> ozone and water vapor are investigated, with and without allowing sea surface temperatures to change, to illuminate the nature of the dynamic and climatic impact. Removing ozone in the lower <span class="hlt">stratosphere</span> without allowing sea surface temperatures to change results in in situ cooling of up to 10{degrees}C in the tropical lower <span class="hlt">stratosphere</span>, with radiative <span class="hlt">warming</span> about half as large in the middle <span class="hlt">stratosphere</span>. The temperature changes induce increases in tropospheric and lower <span class="hlt">stratospheric</span> eddy energy and in the lower <span class="hlt">stratosphere</span> residual circulation of the order of 10%. When sea surface temperatures are allowed to respond to this forcing, the global, annual-average surface air temperature cools by about 1{degrees}C as a result of the decreased ozone greenhouse capacity, reduced tropospheric water vapor, and increased cloud cover. For more realistic ozone changes, as defined in the High-Speed Research Program/Atmospheric Effects of <span class="hlt">Stratospheric</span> Aircraft reports, the <span class="hlt">stratosphere</span> generally cools by a few tenths degrees Celsius. In this case, the surface air temperature change is not significant, due to the conflicting influences of <span class="hlt">stratospheric</span> ozone reduction and tropospheric ozone increase, although high-latitude cooling of close to 0.5{degrees}C does occur consistently. With a more realistic increase of <span class="hlt">stratospheric</span> water vapor of 7%, the middle atmosphere cools by 0.5{degrees}C or less, and the surface temperature change is neither significant nor consistent. Overall, the experiments emphasize that <span class="hlt">stratospheric</span> changes affect tropospheric dynamics, and that tropospheric feedback processes and natural variability are important when assessing the climatic response to aircraft emissions. 21 refs., 20 figs., 3 tabs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015EGUGA..1710223L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015EGUGA..1710223L"><span id="translatedtitle">Optimizing <span class="hlt">stratospheric</span> sulfur geoengineering by seasonally changing sulfur injections</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Laakso, Anton; Partanen, Antti-Ilari; Kokkola, Harri; Lehtinen, Kari; Korhonen, Hannele</p> <p>2015-04-01</p> <p>Solar radiation management (SRM) by <span class="hlt">stratospheric</span> sulfur injection has been shown to have potential in counteracting global <span class="hlt">warming</span> if reducing of greenhouse gases has not been achieved fast enough and if climate <span class="hlt">warming</span> will continue. Injecting large amounts of sulfate particles to the <span class="hlt">stratosphere</span> would increase the reflectivity of the atmosphere and less sunlight would reach the surface. However, the effectivity (per injected sulphur mass unit) of this kind of geoengineering would decrease when amount of injected sulfur is increased. When sulfur concentration increases, <span class="hlt">stratospheric</span> particles would grow to larger sizes which have larger gravitational settling velocity and which do not reflect radiation as efficiently as smaller particles. In many previous studies, sulfur has been assumed to be injected along the equator where yearly mean solar intensity is the highest and from where sulfur is spread equally to both hemispheres. However, the solar intensity will change locally during the year and sulfate has been assumed to be injected and spread to the hemisphere also during winter time, when the solar intensity is low. Thus sulfate injection could be expected to be more effective, if sulfur injection area is changed seasonally. Here we study effects of the different SRM injection scenarios by using two versions of the MPI climate models. First, aerosol spatial and temporal distributions as well as the resulting radiative properties from the SRM are defined by using the global aerosol-climate model ECHAM6.1-HAM2.2-SALSA. After that, the global and regional climate effects from different injection scenarios are predicted by using the Max Planck Institute's Earth System Model (MPI-ESM). We carried out simulations, where 8 Tg of sulfur is injected as SO2 to the <span class="hlt">stratosphere</span> at height of 20-22 km in an area ranging over a 20 degree wide latitude band. Results show that changing the sulfur injection area seasonally would lead to similar global mean shortwave</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19810037718&hterms=Mount+St+Helens&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3D%2528%2528Mount%2BSt%2529%2BHelens%2529','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19810037718&hterms=Mount+St+Helens&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3D%2528%2528Mount%2BSt%2529%2BHelens%2529"><span id="translatedtitle">Long-wave <span class="hlt">stratospheric</span> transmission of Mount St. Helens ejecta</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Kuhn, P. M.; Haughney, L. C.; Innis, R. C.</p> <p>1981-01-01</p> <p>The NASA/Ames Research C-141 aircraft underflew the Mount St. Helens ejecta plume in Utah three days after the eruption. Upward-looking 20-40-microns on-board radiometry provided data resulting in a calculated long-wave transmission of 0.93. From this value, an optical depth of 0.073 is inferred. This value is compared with an accepted background, <span class="hlt">stratospheric</span> infrared optical depth of 0.06. Assumptions on particle size, shortwave albedo, and thermal <span class="hlt">warming</span> imply little surface temperature change caused by the ejecta on the third day immediately following the eruption.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/6848426','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/6848426"><span id="translatedtitle">Long-wave <span class="hlt">stratospheric</span> transmission of Mount St. Helens ejecta</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Kuhn, P.M.; Haughney, L.C.; Innis, R.C.</p> <p>1981-01-01</p> <p>The NASA/Ames Research C-141 aircraft underflew the Mount St. Helens ejecta plume in Utah three days after the eruption. Upward-looking 20--40-..mu..m on-board radiometry provided data resulting in a calculated long-wave transmission of 0.93. From this value, an optical depth of 0.073 is inferred. This value is compared with an accepted background, <span class="hlt">stratospheric</span> infrared optical depth of 0.06. Assumptions on particle size, shortwave albedo, and thermal <span class="hlt">warming</span> imply little surface temperature change caused by the ejecta on the third day immediately following the eruption.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010ACPD...1022019H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010ACPD...1022019H"><span id="translatedtitle">Tropospheric temperature response to <span class="hlt">stratospheric</span> ozone recovery in the 21st century</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hu, Y.; Xia, Y.; Fu, Q.</p> <p>2010-09-01</p> <p>Observations show a stabilization or a weak increase of the <span class="hlt">stratospheric</span> ozone layer since the late 1990s. Recent coupled chemistry-climate model simulations predicted that the <span class="hlt">stratospheric</span> ozone layer will likely return to pre-1980 levels in the middle of the 21st century, as a results of the decline of ozone depleting substances under the 1987 Montreal Protocol. Since the ozone layer is an important component in determining <span class="hlt">stratospheric</span> and tropospheric-surface energy balance, the recovery of the ozone layer may have significant impact on tropospheric-surface climate. Here, using multi-model ensemble results from both the Intergovernmental Panel on Climate Change Fourth Assessment Report (IPCC-AR4) models and coupled chemistry-climate models, we show that as ozone recovery is considered, the troposphere is <span class="hlt">warmed</span> more than that without considering ozone recovery, suggesting an enhancement of tropospheric <span class="hlt">warming</span> due to ozone recovery. It is found that the enhanced tropospheric <span class="hlt">warming</span> is mostly significant in the upper troposphere, with a global mean magnitude of ~0.41 K for 2001-2050. We also find that relatively large enhanced <span class="hlt">warming</span> occurs in the extratropics and polar regions in summer and autumn in both hemispheres while the enhanced <span class="hlt">warming</span> is stronger in the Northern Hemisphere than in the Southern Hemisphere. Enhanced <span class="hlt">warming</span> is also found at the surface. The strongest enhancement of surface <span class="hlt">warming</span> is located in the Arctic in boreal winter. The global annual mean enhancement of surface <span class="hlt">warming</span> is about 0.16 K for 2001-2050.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li class="active"><span>13</span></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_13 --> <div id="page_14" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li class="active"><span>14</span></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="261"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19850019103','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19850019103"><span id="translatedtitle">Measurement of Elements in the <span class="hlt">Stratosphere</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Anderson, J. G.</p> <p>1985-01-01</p> <p>Balloon-borne winch system; <span class="hlt">stratospheric</span> free radicals; <span class="hlt">stratospheric</span> sounding; copper vapor lasers; ozone measurement; NO2 analysis; chlorine chemistry; trace elements; and ClO observations are discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19920000224&hterms=condensed&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dcondensed','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19920000224&hterms=condensed&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dcondensed"><span id="translatedtitle">Condensed Acids In Antartic <span class="hlt">Stratospheric</span> Clouds</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Pueschel, R. F.; Snetsinger, K. G.; Toon, O. B.; Ferry, G. V.; Starr, W. L.; Oberbeck, V. R.; Chan, K. R.; Goodman, J. K.; Livingston, J. M.; Verma, S.; Fong, W.</p> <p>1992-01-01</p> <p>Report dicusses nitrate, sulfate, and chloride contents of <span class="hlt">stratospheric</span> aerosols during 1987 Airborne Antarctic Ozone Experiment. Emphasizes growth of HNO3*3H2O particles in polar <span class="hlt">stratospheric</span> clouds. Important in testing theories concerning Antarctic "ozone hole".</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryId=35285&keyword=Real+AND+earth&actType=&TIMSType=+&TIMSSubTypeID=&DEID=&epaNumber=&ntisID=&archiveStatus=Both&ombCat=Any&dateBeginCreated=&dateEndCreated=&dateBeginPublishedPresented=&dateEndPublishedPresented=&dateBeginUpdated=&dateEndUpdated=&dateBeginCompleted=&dateEndCompleted=&personID=&role=Any&journalID=&publisherID=&sortBy=revisionDate&count=50&CFID=76763061&CFTOKEN=27310628','EPA-EIMS'); return false;" href="http://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryId=35285&keyword=Real+AND+earth&actType=&TIMSType=+&TIMSSubTypeID=&DEID=&epaNumber=&ntisID=&archiveStatus=Both&ombCat=Any&dateBeginCreated=&dateEndCreated=&dateBeginPublishedPresented=&dateEndPublishedPresented=&dateBeginUpdated=&dateEndUpdated=&dateBeginCompleted=&dateEndCompleted=&personID=&role=Any&journalID=&publisherID=&sortBy=revisionDate&count=50&CFID=76763061&CFTOKEN=27310628"><span id="translatedtitle"><span class="hlt">STRATOSPHERIC</span> OZONE DEPLETION: IMPLICATIONS FOR MARINE ECOSYSTEMS</span></a></p> <p><a target="_blank" href="http://oaspub.epa.gov/eims/query.page">EPA Science Inventory</a></p> <p></p> <p></p> <p>The <span class="hlt">stratospheric</span> ozone layer shields the earth from biologically damaging solar ultraviolet radiation. Chlorofluorocarbons (CFCs), used in refrigerants, etc. and halons, used in fire extinguishers, escape into the lower atmosphere and migrate to the <span class="hlt">stratosphere</span>, destroying the ...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2009NatGe...2...28E&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2009NatGe...2...28E&link_type=ABSTRACT"><span id="translatedtitle">Age of <span class="hlt">stratospheric</span> air unchanged within uncertainties over the past 30years</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Engel, A.; Möbius, T.; Bönisch, H.; Schmidt, U.; Heinz, R.; Levin, I.; Atlas, E.; Aoki, S.; Nakazawa, T.; Sugawara, S.; Moore, F.; Hurst, D.; Elkins, J.; Schauffler, S.; Andrews, A.; Boering, K.</p> <p>2009-01-01</p> <p>The rising abundances of greenhouse gases in the atmosphere is associated with an increase in radiative forcing that leads to <span class="hlt">warming</span> of the troposphere, the lower portion of the Earth's atmosphere, and cooling of the <span class="hlt">stratosphere</span> above. A secondary effect of increasing levels of greenhouse gases is a possible change in the <span class="hlt">stratospheric</span> circulation, which could significantly affect chlorofluorocarbon lifetimes, ozone levels and the climate system more generally. Model simulations have shown that the mean age of <span class="hlt">stratospheric</span> air is a good indicator of the strength of the residual circulation, and that this mean age is expected to decrease with rising levels of greenhouse gases in the atmosphere. Here we use balloon-borne measurements of <span class="hlt">stratospheric</span> trace gases over the past 30years to derive the mean age of air from sulphur hexafluoride (SF6) and CO2 mixing ratios. In contrast to the models, these observations do not show a decrease in mean age with time. If models are to make valid predictions of future <span class="hlt">stratospheric</span> ozone levels, and of the coupling between ozone and climate change, a correct description of <span class="hlt">stratospheric</span> transport and possible changes in the transport pathways are necessary.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20020050917&hterms=Light+pollution&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3DLight%2Bpollution','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20020050917&hterms=Light+pollution&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3DLight%2Bpollution"><span id="translatedtitle">Light Absorption of <span class="hlt">Stratospheric</span> Aerosols: Long-Term Trend and Contribution by Aircraft</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Pueschel , R. F.; Gore, Waren J. Y. (Technical Monitor)</p> <p>1997-01-01</p> <p>Measurements of aerosol light-absorption coefficients are useful for studies of radiative transfer and heating rates. Ogren appears to have published the first light- absorption coefficients in the <span class="hlt">stratosphere</span> in 1981, followed by Clarke in 1983 and Pueschel in 1992. Because most <span class="hlt">stratospheric</span> soot appears to be due to aircraft operations, application of an aircraft soot aerosol emission index to projected fuel consumption suggests a threefold increase of soot loading and light absorption by 2025. Together, those four data sets indicate an increase in mid-visible light extinction at a rate of 6 % per year. This trend is similar to the increase per year of sulfuric acid aerosol and of commercial fleet size. The proportionality between stepped-up aircraft operations above the tropopause and increases in <span class="hlt">stratospheric</span> soot and sulfuric acid aerosol implicate aircraft as a source of <span class="hlt">stratospheric</span> pollution. Because the strongly light-absorbing soot and the predominantly light-scattering sulfuric acid aerosol increase at similar rates, however, the mid-visible <span class="hlt">stratospheric</span> aerosol single scatter albedo is expected to remain constant and not approach a critical value of 0.98 at which <span class="hlt">stratospheric</span> cooling could change to <span class="hlt">warming</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19910018326','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19910018326"><span id="translatedtitle">Background <span class="hlt">stratospheric</span> aerosol reference model</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Mccormick, M. P.; Wang, P.</p> <p>1989-01-01</p> <p>In this analysis, a reference background <span class="hlt">stratospheric</span> aerosol optical model is developed based on the nearly global SAGE 1 satellite observations in the non-volcanic period from March 1979 to February 1980. Zonally averaged profiles of the 1.0 micron aerosol extinction for the tropics and the mid- and high-altitudes for both hemispheres are obtained and presented in graphical and tabulated form for the different seasons. In addition, analytic expressions for these seasonal global zonal means, as well as the yearly global mean, are determined according to a third order polynomial fit to the vertical profile data set. This proposed background <span class="hlt">stratospheric</span> aerosol model can be useful in modeling studies of <span class="hlt">stratospheric</span> aerosols and for simulations of atmospheric radiative transfer and radiance calculations in atmospheric remote sensing.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://eric.ed.gov/?q=Ozone+AND+depletion&pg=5&id=EJ191220','ERIC'); return false;" href="http://eric.ed.gov/?q=Ozone+AND+depletion&pg=5&id=EJ191220"><span id="translatedtitle">Chemistry and Pollution of the <span class="hlt">Stratosphere</span>.</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Donovan, R. J.</p> <p>1978-01-01</p> <p>Presents an outline of the chemistry involved and the steps which are being taken to gain a better understanding of the <span class="hlt">stratosphere</span>. Chemical composition of natural <span class="hlt">stratosphere</span> and depletion of ozone in the <span class="hlt">stratosphere</span> by man-made pollutants are covered. (HM)</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19990103360','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19990103360"><span id="translatedtitle">Statistical Perspectives on <span class="hlt">Stratospheric</span> Transport</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Sparling, L. C.</p> <p>1999-01-01</p> <p>Long-lived tropospheric source gases, such as nitrous oxide, enter the <span class="hlt">stratosphere</span> through the tropical tropopause, are transported throughout the <span class="hlt">stratosphere</span> by the Brewer-Dobson circulation, and are photochemically destroyed in the upper <span class="hlt">stratosphere</span>. These chemical constituents, or "tracers" can be used to track mixing and transport by the <span class="hlt">stratospheric</span> winds. Much of our understanding about the <span class="hlt">stratospheric</span> circulation is based on large scale gradients and other spatial features in tracer fields constructed from satellite measurements. The point of view presented in this paper is different, but complementary, in that transport is described in terms of tracer probability distribution functions (PDFs). The PDF is computed from the measurements, and is proportional to the area occupied by tracer values in a given range. The flavor of this paper is tutorial, and the ideas are illustrated with several examples of transport-related phenomena, annotated with remarks that summarize the main point or suggest new directions. One example shows how the multimodal shape of the PDF gives information about the different branches of the circulation. Another example shows how the statistics of fluctuations from the most probable tracer value give insight into mixing between different regions of the atmosphere. Also included is an analysis of the time-dependence of the PDF during the onset and decline of the winter circulation, and a study of how "bursts" in the circulation are reflected in transient periods of rapid evolution of the PDF. The dependence of the statistics on location and time are also shown to be important for practical problems related to statistical robustness and satellite sampling. The examples illustrate how physically-based statistical analysis can shed some light on aspects of <span class="hlt">stratospheric</span> transport that may not be obvious or quantifiable with other types of analyses. An important motivation for the work presented here is the need for synthesis of the</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20020041487&hterms=distribution+commercial&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Ddistribution%2Bcommercial','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20020041487&hterms=distribution+commercial&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Ddistribution%2Bcommercial"><span id="translatedtitle">Pole-to-Pole Distribution of <span class="hlt">Stratospheric</span> Black Carbon (Soot) Aerosol from Aircraft</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Pueschel, R. F.; Ferry, G. V.; Verma, S.; Howard, S. D.; Strawa, Anthony W. (Technical Monitor)</p> <p>1995-01-01</p> <p>The distribution of black carbon (soot) aerosol (BCA) in the atmosphere is of interest for several reasons: (1) Because BCA has the highest absorption cross section of any compound known, it can absorb solar radiation to cause atmospheric <span class="hlt">warming</span>. (2) Because it is a strong adsorber of gases, it can catalyze heterogeneous reactions to change the chemical composition of the atmosphere.(3) If aircraft are a major source of BCA, it is an important tracer of aircraft emissions. Analysis for BCA of impactor samples from Arctic and Antarctic deployments, utilizing particle morphology of scanning electron microscopy images, permits the following conclusions: (1) The BCA concentration in the northern <span class="hlt">stratosphere</span> varies between 0 and 2.6 ng m-3 averaging 0.6 ng/cu m. (2) This BCA loading is commensurate with estimated fuel consumptions in the <span class="hlt">stratosphere</span> by the current commercial fleet and an emission index E=0.03 g BCA per kg fuel burnt which was measured in jet exhaust at al titude.Thus, most <span class="hlt">stratospheric</span> BCA in the northern <span class="hlt">stratosphere</span> results from aircraft emissions. The background BCA concentration in the southern <span class="hlt">stratosphere</span> varies between 0 and 0.6 ng cu m averaging 0.1 ng/cu m. This strong meridional gradient implies that <span class="hlt">stratospheric</span> BCA residence time- is shorter than are mixing times between hemispheres. Projected annual fuel consumption of a future supersonic commercial fleet is 7E13 g. This fleet would increase <span class="hlt">stratospheric</span> BCA loadings by a factor of 2-3, because almost all fuel would be burnt above the tropopause. An improved EI(BCA) by a factor of ten would result in an increase of <span class="hlt">stratospheric</span> BCA loadings by approximately 50 %.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JASTP.132...74S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JASTP.132...74S"><span id="translatedtitle">Extreme <span class="hlt">stratospheric</span> springs and their consequences for the onset of polar mesospheric clouds</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Siskind, David E.; Allen, Douglas R.; Randall, Cora E.; Harvey, V. Lynn; Hervig, Mark E.; Lumpe, Jerry; Thurairajah, Brentha; Bailey, Scott M.; Russell, James M.</p> <p>2015-09-01</p> <p>We use data from the Aeronomy of Ice in the Mesosphere (AIM) explorer and from the NASA Modern Era Retrospective Analysis for Research and Applications (MERRA) <span class="hlt">stratospheric</span> analysis to explore the variability in the onset of the Northern Hemisphere (NH) Polar Mesospheric Cloud (PMC) season. Consistent with recently published results, we show that the early onset of the NH PMC season in 2013 was accompanied by a <span class="hlt">warm</span> springtime <span class="hlt">stratosphere</span>; conversely, we show that the late onset in 2008 coincides with a very cold springtime <span class="hlt">stratosphere</span>. Similar <span class="hlt">stratospheric</span> temperature anomalies for 1997 and 2011 also are connected either directly, through observed temperatures, or indirectly, through an early PMC onset, to conditions near the mesopause. These 4 years, 2008, 1997, 2011, and 2013 represent the extremes of <span class="hlt">stratospheric</span> springtime temperatures seen in the MERRA analysis and correspond to analogous extrema in planetary wave activity. The three years with enhanced planetary wave activity (1997, 2011 and 2013) are shown to coincide with the recently identified <span class="hlt">stratospheric</span> Frozen In Anticyclone (FrIAC) phenomenon. FrIACs in 1997 and 2013 are associated with early PMC onsets; however, the dramatic FrIAC of 2011 is not. This may be because the 2011 FrIAC occurred too early in the spring. The link between NH PMC onset and <span class="hlt">stratospheric</span> FrIAC occurrences represents a new mode of coupling between the <span class="hlt">stratosphere</span> and mesosphere. Since FrIACs appear to be more frequent in recent years, we speculate that as a result, PMCs may occur earlier as well. Finally we compare the zonal mean zonal winds and observed gravity wave activity for the FrIACs of 2011 and 2013. We find no evidence that gravity wave activity was favored in 2013 relative to 2011, thus suggesting that direct forcing by planetary waves was the key mechanism in accelerating the cooling and moistening of the NH mesopause region in May of 2013.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011GeoRL..38.3808M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011GeoRL..38.3808M"><span id="translatedtitle">Quantifying <span class="hlt">stratospheric</span> ozone trends: Complications due to <span class="hlt">stratospheric</span> cooling</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>McLinden, C. A.; Fioletov, V.</p> <p>2011-02-01</p> <p>Recent studies suggest that ozone turnaround (the second stage of ozone recovery) is near. Determining precisely when this occurs, however, will be complicated by greenhouse gas-induced <span class="hlt">stratospheric</span> cooling as ozone trends derived from profile data in different units and/or vertical co-ordinates will not agree. <span class="hlt">Stratospheric</span> cooling leads to simultaneous trends in air density and layer thicknesses, confounding the interpretation of ozone trends. A simple model suggests that instruments measuring ozone in different units may differ as to the onset of turnaround by a decade, with some indicting a continued decline while others an increase. This concept was illustrated by examining the long-term (1979-2005) ozone trends in the SAGE (<span class="hlt">Stratospheric</span> Aerosol and Gas Experiment) and SBUV (Solar Backscatter Ultraviolet) time series. Trends from SAGE, which measures number density as a function of altitude, and SBUV, which measures partial column as a function of pressure, are known to differ by 4-6%/decade in the upper <span class="hlt">stratosphere</span>. It is shown that this long-standing difference can be reconciled to within 2%/decade when the trend in temperature is properly accounted for.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/5365127','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/5365127"><span id="translatedtitle">Policies on global <span class="hlt">warming</span> and ozone depletion</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Green, B.</p> <p>1987-04-01</p> <p>The recent discovery of a dramatic seasonal drop in the amount of ozone over Antarctica has catalyzed concern for protection of <span class="hlt">stratospheric</span> ozone, the layer of gas that shields the entire planet from excess ultraviolet radiation. Conservative scientific models predict about a 5% reduction in the amount of global ozone by the middle of the next century, with large local variations. The predicted global <span class="hlt">warming</span> from increased emissions of greenhouse gases will also have differing effects on local climate and weather conditions and consequently on agriculture. Although numerous uncertainties are associated with both ozone depletion and a global <span class="hlt">warming</span>, there is a consensus that world leaders need to address the problems. The US Congress is now beginning to take note of the task. In this article, one representative outlines some perceptions of the problems and the policy options available to Congress.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19920006216','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19920006216"><span id="translatedtitle">Halocarbon ozone depletion and global <span class="hlt">warming</span> potentials</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Cox, Richard A.; Wuebbles, D.; Atkinson, R.; Connell, Peter S.; Dorn, H. P.; Derudder, A.; Derwent, Richard G.; Fehsenfeld, F. C.; Fisher, D.; Isaksen, Ivar S. A.</p> <p>1990-01-01</p> <p>Concern over the global environmental consequences of fully halogenated chlorofluorocarbons (CFCs) has created a need to determine the potential impacts of other halogenated organic compounds on <span class="hlt">stratospheric</span> ozone and climate. The CFCs, which do not contain an H atom, are not oxidized or photolyzed in the troposphere. These compounds are transported into the <span class="hlt">stratosphere</span> where they decompose and can lead to chlorine catalyzed ozone depletion. The hydrochlorofluorocarbons (HCFCs or HFCs), in particular those proposed as substitutes for CFCs, contain at least one hydrogen atom in the molecule, which confers on these compounds a much greater sensitivity toward oxidation by hydroxyl radicals in the troposphere, resulting in much shorter atmospheric lifetimes than CFCs, and consequently lower potential for depleting ozone. The available information is reviewed which relates to the lifetime of these compounds (HCFCs and HFCs) in the troposphere, and up-to-date assessments are reported of the potential relative effects of CFCs, HCFCs, HFCs, and halons on <span class="hlt">stratospheric</span> ozone and global climate (through 'greenhouse' global <span class="hlt">warming</span>).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015EGUGA..17.6654G&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015EGUGA..17.6654G&link_type=ABSTRACT"><span id="translatedtitle">Effect of Recent Sea Surface Temperature Trends on the Springtime Cooling Trend of the Arctic <span class="hlt">Stratospheric</span> Vortex</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Garfinkel, Chaim; Oman, Luke; Hurwitz, Margaret</p> <p>2015-04-01</p> <p>The springtime Arctic polar vortex has cooled significantly over the satellite era, with consequences for ozone concentrations in the springtime transition season. The causes of this cooling trend are deduced by using comprehensive chemistry-climate model experiments. Approximately half of the satellite era early springtime cooling trend in the Arctic lower <span class="hlt">stratosphere</span> was caused by changing sea surface temperatures (SSTs). An ensemble of experiments forced only by changing SSTs is compared to an ensemble of experiments in which both the observed SSTs and chemically- and radiatively-active trace species are changing. By comparing the two ensembles, it is shown that <span class="hlt">warming</span> of Indian Ocean, North Pacific, and North Atlantic SSTs, and cooling of the tropical Pacific, have strongly contributed to recent polar <span class="hlt">stratospheric</span> cooling in late winter and early spring, and to a weak polar <span class="hlt">stratospheric</span> <span class="hlt">warming</span> in early winter. When concentrations of ozone-depleting substances and greenhouse gases are fixed, polar ozone concentrations show a small but robust decline due to changing SSTs. Ozone changes are magnified in the presence of changing gas concentrations. The <span class="hlt">stratospheric</span> changes can be understood by examining the tropospheric height and heat flux anomalies generated by the anomalous SSTs. Finally, recent SST changes have contributed to a decrease in the frequency of late winter <span class="hlt">stratospheric</span> sudden <span class="hlt">warmings</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016ACP....16.8791T&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016ACP....16.8791T&link_type=ABSTRACT"><span id="translatedtitle">How <span class="hlt">stratospheric</span> are deep <span class="hlt">stratospheric</span> intrusions? LUAMI 2008</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Trickl, Thomas; Vogelmann, Hannes; Fix, Andreas; Schäfler, Andreas; Wirth, Martin; Calpini, Bertrand; Levrat, Gilbert; Romanens, Gonzague; Apituley, Arnoud; Wilson, Keith M.; Begbie, Robert; Reichardt, Jens; Vömel, Holger; Sprenger, Michael</p> <p>2016-07-01</p> <p>A large-scale comparison of water-vapour vertical-sounding instruments took place over central Europe on 17 October 2008, during a rather homogeneous deep <span class="hlt">stratospheric</span> intrusion event (LUAMI, Lindenberg Upper-Air Methods Intercomparison). The measurements were carried out at four observational sites: Payerne (Switzerland), Bilthoven (the Netherlands), Lindenberg (north-eastern Germany), and the Zugspitze mountain (Garmisch-Partenkichen, German Alps), and by an airborne water-vapour lidar system creating a transect of humidity profiles between all four stations. A high data quality was verified that strongly underlines the scientific findings. The intrusion layer was very dry with a minimum mixing ratios of 0 to 35 ppm on its lower west side, but did not drop below 120 ppm on the higher-lying east side (Lindenberg). The dryness hardens the findings of a preceding study ("Part 1", Trickl et al., 2014) that, e.g., 73 % of deep intrusions reaching the German Alps and travelling 6 days or less exhibit minimum mixing ratios of 50 ppm and less. These low values reflect values found in the lowermost <span class="hlt">stratosphere</span> and indicate very slow mixing with tropospheric air during the downward transport to the lower troposphere. The peak ozone values were around 70 ppb, confirming the idea that intrusion layers depart from the lowermost edge of the <span class="hlt">stratosphere</span>. The data suggest an increase of ozone from the lower to the higher edge of the intrusion layer. This behaviour is also confirmed by <span class="hlt">stratospheric</span> aerosol caught in the layer. Both observations are in agreement with the idea that sections of the vertical distributions of these constituents in the source region were transferred to central Europe without major change. LAGRANTO trajectory calculations demonstrated a rather shallow outflow from the <span class="hlt">stratosphere</span> just above the dynamical tropopause, for the first time confirming the conclusions in "Part 1" from the Zugspitze CO observations. The trajectories qualitatively explain</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19820051667&hterms=dehydration&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Ddehydration','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19820051667&hterms=dehydration&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Ddehydration"><span id="translatedtitle">A dehydration mechanism for the <span class="hlt">stratosphere</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Danielsen, E. F.</p> <p>1982-01-01</p> <p>Although mean circulations are generally credited with dehydration of the earth's <span class="hlt">stratosphere</span>, convective instability in the tropics converts mean circulations to small residuals of local convective circulations. The effects of large cumulonimbus which penetrate the <span class="hlt">stratosphere</span> and form huge anvils in the lower <span class="hlt">stratosphere</span> are discussed with respect to hydration and dehydration of the <span class="hlt">stratosphere</span>. Radiative heating at anvil base combined with cooling at anvil top drives a dehydration engine considered essential to explain the dry <span class="hlt">stratosphere</span>. Seasonal and longitudinal variations in dehydration potentials are examined with maximum potential attributed to Micronesian area during winter and early spring.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/569483','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/569483"><span id="translatedtitle">Stable isotope enrichment in <span class="hlt">stratospheric</span> nitrous oxide</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Rahn, T.; Wahlen, M.</p> <p>1997-12-05</p> <p>Nitrous oxide is a greenhouse gas that also plays a role in the cycling of <span class="hlt">stratospheric</span> ozone. Air samples from the lower <span class="hlt">stratosphere</span> exhibit {sup 15}N/{sup 14}N and {sup 18}O/{sup 16}O enrichment in nitrous oxide, which can be accounted for with a simple model describing an irreversible destruction process. The observed enrichments are quite large and incompatible with those determined for the main <span class="hlt">stratospheric</span> nitrous oxide loss processes of photolysis and reaction with excited atomic oxygen. Thus, although no <span class="hlt">stratospheric</span> source needs to be invoked, the data indicate that present understanding of <span class="hlt">stratospheric</span> nitrous oxide chemistry is incomplete. 21 refs., 1 fig., 1 tab.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19850013561','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19850013561"><span id="translatedtitle">21 Layer troposphere-<span class="hlt">stratosphere</span> climate model</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Rind, D.; Suozzo, R.; Lacis, A.; Russell, G.; Hansen, J.</p> <p>1984-01-01</p> <p>The global climate model is extended through the <span class="hlt">stratosphere</span> by increasing the vertical resolution and raising the rigid model top to the 0.01 mb (75 km) level. The inclusion of a realistic <span class="hlt">stratosphere</span> is necessary for the investigation of the climate effects of <span class="hlt">stratospheric</span> perturbations, such as changes of ozone, aerosols or solar ultraviolet irradiance, as well as for studying the effect on the <span class="hlt">stratosphere</span> of tropospheric climate changes. The observed temperature and wind patterns throughout the troposphere and <span class="hlt">stratosphere</span> are simulated. In addition to the excess planetary wave amplitude in the upper <span class="hlt">stratosphere</span>, other model deficiences include the Northern Hemisphere lower <span class="hlt">stratospheric</span> temperatures being 5 to 10 C too cold in winter at high latitudes and the temperature at 50 to 60 km altitude near the equator are too cold. Methods of correcting these deficiencies are discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20030053448','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20030053448"><span id="translatedtitle">The Unusual Southern Hemisphere <span class="hlt">Stratosphere</span> Winter of 2002</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Newman, Paul A.; Nash, Eric R.</p> <p>2003-01-01</p> <p>The southern hemisphere <span class="hlt">stratospheric</span> winter of 2002 was the most unusual winter yet observed in the southern hemisphere climate record. Temperatures near the edge of the Antarctic polar vortex were considerably warmer than normal over the entire course of the winter. The polar night jet was considerably weaker than normal, and was displaced more poleward than has been observed in previous winters. These record high temperatures and weak jet resulted from a series of wave events that took place over the course of the winter. The first large event occurred on 15 May, and the final <span class="hlt">warming</span> occurred on 25 October. The propagation of these wave events from the troposphere is diagnosed from time series of Eliassen-Palm flux vectors. The wave events tended to occur irregularly over the course of the winter, and pre-conditioned the polar night jet for the extremely large wave event of 22 September. This large wave event resulted in the first ever observed major <span class="hlt">stratospheric</span> <span class="hlt">warming</span> in the southern hemisphere. This wave event split the Antarctic ozone hole. The combined effect of the wave events of the 2002 winter resulted in the smallest ozone hole observed since 1988.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014EGUGA..1615073C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014EGUGA..1615073C"><span id="translatedtitle">Role of Methane in Antarctic <span class="hlt">Stratospheric</span> Ozone Recovery</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Calvo, Natalia; Kinnison, Douglas E.; Marsh, Daniel R.; Garcia, Rolando R.; Palmeiro, Froila</p> <p>2014-05-01</p> <p>Observational and modeling studies have shown the impact of changes in Antarctic <span class="hlt">stratospheric</span> ozone on tropospheric climate in austral spring and summer. In the future, effects of increasing greenhouse gases and ozone depleting substances oppose each other. Projections show potential impact of ozone recovery on precipitation, carbon uptake in the Southern Hemisphere ocean, Antarctic ice sheets and Southern Hemisphere sea ice. In order to quantify properly the tropospheric impacts of ozone recovery, future Antarctic ozone changes in the upper troposphere lower <span class="hlt">stratosphere</span> region and the role (if any) of increasing greenhouse gases in ozone recovery need to be evaluated. To do so, we use the National Center for Atmospheric Research's Community Earth System Model, CESM, with the high-top version of the atmospheric component, CESM(WACCM), which is a fully coupled chemistry climate model. Three climate change scenarios (RCP2.6, RCP4.5 and RCP8.5) of 3 simulations each from 2005 to 2065 are analyzed. In scenario RCP2.6, the largest ozone recovery is simulated in October and November at 50hPa and it is followed by the largest response in temperature in November and December at 70hPa. While the response in RCP4.5 in ozone and temperature is almost identical to that in RCP2.6 in the upper troposphere and lower <span class="hlt">stratosphere</span> region, scenario RCP8.5 shows significantly stronger ozone recovery and <span class="hlt">warming</span> than the other two scenarios, particularly in November and December at 70hPa in ozone and 100hPa in temperature. We show that this is due to larger amounts of methane in RCP8.5 compared to the other two scenarios, which reduces catalytic ozone loss locally. Differences across scenarios in advection of ozone from the source region in the tropical <span class="hlt">stratosphere</span> do not play a significant role.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li class="active"><span>14</span></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_14 --> <div id="page_15" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li class="active"><span>15</span></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="281"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016ACP....16.7559X','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016ACP....16.7559X"><span id="translatedtitle">Strong modification of <span class="hlt">stratospheric</span> ozone forcing by cloud and sea-ice adjustments</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Xia, Yan; Hu, Yongyun; Huang, Yi</p> <p>2016-06-01</p> <p>We investigate the climatic impact of <span class="hlt">stratospheric</span> ozone recovery (SOR), with a focus on the surface temperature change in atmosphere-slab ocean coupled climate simulations. We find that although SOR would cause significant surface <span class="hlt">warming</span> (global mean: 0.2 K) in a climate free of clouds and sea ice, it causes surface cooling (-0.06 K) in the real climate. The results here are especially interesting in that the <span class="hlt">stratosphere</span>-adjusted radiative forcing is positive in both cases. Radiation diagnosis shows that the surface cooling is mainly due to a strong radiative effect resulting from significant reduction of global high clouds and, to a lesser extent, from an increase in high-latitude sea ice. Our simulation experiments suggest that clouds and sea ice are sensitive to <span class="hlt">stratospheric</span> ozone perturbation, which constitutes a significant radiative adjustment that influences the sign and magnitude of the global surface temperature change.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015ApJ...813L...3K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015ApJ...813L...3K"><span id="translatedtitle"><span class="hlt">Stratospheric</span> Temperatures and Water Loss from Moist Greenhouse Atmospheres of Earth-like Planets</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kasting, James F.; Chen, Howard; Kopparapu, Ravi K.</p> <p>2015-11-01</p> <p>A radiative-convective climate model is used to calculate <span class="hlt">stratospheric</span> temperatures and water vapor concentrations for ozone-free atmospheres warmer than that of modern Earth. Cold, dry <span class="hlt">stratospheres</span> are predicted at low surface temperatures, in agreement with recent 3D calculations. However, at surface temperatures above 350 K, the <span class="hlt">stratosphere</span> <span class="hlt">warms</span> and water vapor becomes a major upper atmospheric constituent, allowing water to be lost by photodissociation and hydrogen escape. Hence, a moist greenhouse explanation for loss of water from Venus, or some exoplanet receiving a comparable amount of stellar radiation, remains a viable hypothesis. Temperatures in the upper parts of such atmospheres are well below those estimated for a gray atmosphere, and this factor should be taken into account when performing inverse climate calculations to determine habitable zone boundaries using 1D models.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20040074999&hterms=ultraviolet+radiation&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3D%2528ultraviolet%2Bradiation%2529','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20040074999&hterms=ultraviolet+radiation&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3D%2528ultraviolet%2Bradiation%2529"><span id="translatedtitle">Ultraviolet Radiation and <span class="hlt">Stratospheric</span> Ozone</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Stolarski, R.</p> <p>2003-01-01</p> <p>Ultraviolet radiation from the sun produces ozone in the <span class="hlt">stratosphere</span> and it participates in the destruction of ozone. Absorption of solar ultraviolet radiation by ozone is the primary heating mechanism leading to the maximum in temperature at the stratopause. Variations of solar ultraviolet radiation on both the 27-day solar rotation period and the 11-year solar cycle affect ozone by several mechanisms. The temperature and ozone in the upper <span class="hlt">stratosphere</span> respond to solar uv variations as a coupled system. An increase in uv leads to an increase in the production of ozone through the photolysis of molecular oxygen. An increase in uv leads to an increase in temperature through the heating by ozone photolysis. The increase in temperature leads to a partially-offsetting decrease in ozone through temperature-dependent reaction rate coefficients. The ozone variation modulates the heating by ozone photolysis. The increase in ozone at solar maximum enhances the uv heating. The processes are understood and supported by long-term data sets. Variation in the upper <span class="hlt">stratospheric</span> temperatures will lead to a change in the behavior of waves propagating upward from the troposphere. Changes in the pattern of wave dissipation will lead to acceleration or deceleration of the mean flow and changes in the residual or transport circulation. This mechanism could lead to the propagation of the solar cycle uv variation from the upper <span class="hlt">stratosphere</span> downward to the lower <span class="hlt">stratosphere</span>. This process is not well-understood and has been the subject of an increasing number of model studies. I will review the data analyses for solar cycle and their comparison to model results.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015DPS....4731116H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015DPS....4731116H"><span id="translatedtitle">Saturn's <span class="hlt">Stratospheric</span> Water Vapor Distribution</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hesman, Brigette E.; Bjoraker, Gordon L.; Achterberg, Richard K.; Romani, Paul N.; Irwin, Patrick G. J.</p> <p>2015-11-01</p> <p>Water is a sought after commodity in the solar system. It is used as an indication of life, planetary formation timescales, and signatures of past cometary impacts. In Saturn’s atmosphere there are two sources of water: an internal primordial reservoir that is confined to the troposphere, and an external source of unknown origin that delivers water to the <span class="hlt">stratosphere</span>. Potential sources of <span class="hlt">stratospheric</span> water include: Saturn’s main rings (via neutral infall and/or ions transported along magnetic field lines - “Ring Rain”), interplanetary dust particles, and the E-ring that is supplied with water from the plumes of Enceladus. Measuring the latitudinal and seasonal variation of H2O on Saturn will constrain the source of Saturn’s <span class="hlt">stratospheric</span> water.Cassini’s Composite InfraRed Spectrometer (CIRS) has detected emission lines of H2O on Saturn at wavelengths of 40 and 50 microns. CIRS also retrieves the temperature of the <span class="hlt">stratosphere</span> using CH4 lines at 7.7 microns. Using our retrieved temperatures, we derive the mole fraction of H2O at the 0.5-5 mbar level for comparison with water-source models. The latitudinal variation of <span class="hlt">stratospheric</span> water vapor will be presented as a first step in understanding the external source of water on Saturn. The observed local maximum near Saturn’s equator supports either a neutral infall from the rings or a source in the E-ring. We will look for secondary maxima at mid-latitudes to determine whether “Ring Rain” also contributes to the inventory of water in Saturn’s upper atmosphere.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFM.P41B2058H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFM.P41B2058H"><span id="translatedtitle">Saturn's <span class="hlt">Stratospheric</span> Water Vapor Distribution</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hesman, B. E.</p> <p>2015-12-01</p> <p>Water is a sought after commodity in the solar system. It is used as an indication of life, planetary formation timescales, and signatures of past cometary impacts. In Saturn's atmosphere there are two sources of water: an internal primordial reservoir that is confined to the troposphere, and an external source of unknown origin that delivers water to the <span class="hlt">stratosphere</span>. Potential sources of <span class="hlt">stratospheric</span> water include: Saturn's main rings (via neutral infall and/or ions transported along magnetic field lines - "Ring Rain"), interplanetary dust particles, and the E-ring that is supplied with water from the plumes of Enceladus. Measuring the latitudinal and seasonal variation of H2O on Saturn will constrain the source of Saturn's <span class="hlt">stratospheric</span> water. Cassini's Composite InfraRed Spectrometer (CIRS) has detected emission lines of H2O on Saturn at wavelengths of 40 and 50 microns. CIRS also retrieves the temperature of the <span class="hlt">stratosphere</span> using CH4 lines at 7.7 microns. Using our retrieved temperatures, we derive the mole fraction of H2O at the 0.5-5 mbar level for comparison with water-source models. The latitudinal variation of <span class="hlt">stratospheric</span> water vapor between 2004-2009 will be presented as a first step in understanding the external source of water on Saturn. The observed local maximum near Saturn's equator supports either a neutral infall from the rings or a source in the E-ring. We will look for secondary maxima at mid-latitudes to determine whether "Ring Rain" also contributes to the inventory of water in Saturn's upper atmosphere.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015JGRD..120.5404G&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015JGRD..120.5404G&link_type=ABSTRACT"><span id="translatedtitle">Effect of recent sea surface temperature trends on the Arctic <span class="hlt">stratospheric</span> vortex</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Garfinkel, C. I.; Hurwitz, M. M.; Oman, L. D.</p> <p>2015-06-01</p> <p>Comprehensive chemistry-climate model experiments and observational data are used to show that up to half of the satellite era early springtime cooling trend in the Arctic lower <span class="hlt">stratosphere</span> was caused by changing sea surface temperatures (SSTs). An ensemble of experiments forced only by changing SSTs is compared to an ensemble of experiments in which both the observed SSTs and chemically and radiatively active trace species are changing. By comparing the two ensembles, it is shown that <span class="hlt">warming</span> of Indian Ocean, North Pacific, and North Atlantic SSTs and cooling of the tropical Pacific have strongly contributed to recent polar <span class="hlt">stratospheric</span> cooling in late winter and early spring. When concentrations of ozone-depleting substances and greenhouse gases are fixed, polar ozone concentrations show a small but robust decline due to changing SSTs. Ozone loss is larger in the presence of changing concentrations of ozone-depleting substances and greenhouse gases. The <span class="hlt">stratospheric</span> changes can be understood by examining the tropospheric height and heat flux anomalies generated by the anomalous SSTs. Finally, recent SST changes have contributed to a decrease in the frequency of late winter <span class="hlt">stratospheric</span> sudden <span class="hlt">warmings</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016IzAOP..52....1V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016IzAOP..52....1V"><span id="translatedtitle">Analysis of the reproduction of dynamic processes in the <span class="hlt">stratosphere</span> using the climate model of the institute of numerical mathematics, Russian academy of sciences</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Vargin, P. N.; Volodin, E. M.</p> <p>2016-01-01</p> <p>The reproduction of dynamic processes in the <span class="hlt">stratosphere</span> at extratropical latitudes is considered in calculations of the atmospheric module of the global climate model of the Institute of Numerical Mathematics, Russian Academy of Sciences, with an upper boundary of 0.2 hPa (~60 km) for the period from 1979 to 2008 in comparison with the data observational. Changes in temperature, zonal wind, activity of planetary waves, heat fluxes in the lower <span class="hlt">stratosphere</span>, and sudden <span class="hlt">stratospheric</span> <span class="hlt">warmings</span> with the displacement and splitting of the polar vortex, as well as the distribution of associated circulation anomalies in the troposphere, are analyzed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19870066897&hterms=masato&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dmasato','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19870066897&hterms=masato&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dmasato"><span id="translatedtitle">Dynamical factors affecting ozone mixing ratios in the Antarctic lower <span class="hlt">stratosphere</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Shiotani, Masato; Gille, John C.</p> <p>1987-01-01</p> <p>An account is given of the climatology and interannual variability of dynamical quantities and ozone mixing ratios during the Southern Hemisphere spring for 1979-1984. The seasonal variation in temperature in the lower <span class="hlt">stratosphere</span> is repeatable; a steep decrease in zonal mean ozone mixing ratios is observed around 60 deg S toward the South Pole in September which, with time, becomes shallower in association with minor <span class="hlt">warmings</span> and a final <span class="hlt">warming</span>. Climatological synoptic charts in the lower <span class="hlt">stratosphere</span> show the circumpolar circulation in the geopotential height field and the prominence of planetary wave 1 in the temperature and ozone fields. When wave activity is strong, there are weaker westeries, higher temperatures, and higher ozone mixing ratios at high latitudes.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016ERL....11c4012F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016ERL....11c4012F"><span id="translatedtitle">Quantifying the temperature-independent effect of <span class="hlt">stratospheric</span> aerosol geoengineering on global-mean precipitation in a multi-model ensemble</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ferraro, Angus J.; Griffiths, Hannah G.</p> <p>2016-03-01</p> <p>The reduction in global-mean precipitation when <span class="hlt">stratospheric</span> aerosol geoengineering is used to counterbalance global <span class="hlt">warming</span> from increasing carbon dioxide (CO2) concentrations has been mainly attributed to the temperature-independent effect of CO2 on atmospheric radiative cooling. We demonstrate here that <span class="hlt">stratospheric</span> sulphate aerosol itself also acts to reduce global-mean precipitation independent of its effects on temperature. The temperature-independent effect of <span class="hlt">stratospheric</span> aerosol geoenginering on global-mean precipitation is calculated by removing temperature-dependent effects from climate model simulations of the Geoengineering Model Intercomparison Project (GeoMIP). When sulphate aerosol is injected into the <span class="hlt">stratosphere</span> at a rate of 5 Tg SO2 per year the aerosol reduces global-mean precipitation by approximately 0.2 %, though multiple ensemble members are required to separate this effect from internal variability. For comparison, the precipitation reduction from the temperature-independent effect of increasing CO2 concentrations under the RCP4.5 scenario of the future is approximately 0.5 %. The temperature-independent effect of <span class="hlt">stratospheric</span> sulphate aerosol arises from the aerosol’s effect on tropospheric radiative cooling. Radiative transfer calculations show this is mainly due to increasing downward emission of infrared radiation by the aerosol, but there is also a contribution from the <span class="hlt">stratospheric</span> <span class="hlt">warming</span> the aerosol causes. Our results suggest climate model simulations of solar dimming can capture the main features of the global-mean precipitation response to <span class="hlt">stratospheric</span> aerosol geoengineering.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016JGRD..121.6085P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016JGRD..121.6085P"><span id="translatedtitle">Transport versus energetic particle precipitation: Northern polar <span class="hlt">stratospheric</span> NOx and ozone in January-March 2012</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Päivärinta, S.-M.; Verronen, P. T.; Funke, B.; Gardini, A.; Seppälä, A.; Andersson, M. E.</p> <p>2016-05-01</p> <p>In early 2012, a strong sudden <span class="hlt">stratospheric</span> <span class="hlt">warming</span> (SSW) took place, accompanied by several medium-scale solar proton events (SPEs). Here we use a chemistry transport model (CTM) in order to assess the relative contributions of (1) intensified downward transport of odd nitrogen (NOx) and (2) in situ production of NOx by protons, on <span class="hlt">stratospheric</span> NOx and ozone during January-March 2012. The CTM is constrained by an upper boundary condition for reactive nitrogen (NOy) species, based on satellite observations from Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) on board Envisat, and includes a new parameterization of the SPE-caused effects on NOy and odd hydrogen (HOx) species. We found that the amount of NOx increases due to both transport and in situ production effects, the intensified descent of NOx dominating the middle and upper <span class="hlt">stratospheric</span> impact. The model results indicate NOx enhancements of 120-3300% (5-48 ppbv) between 38 and 50 km, caused by the transport of mesosphere/lower thermosphere NOx down to the <span class="hlt">stratosphere</span> following the SSW. The SPEs increase NOx by up to 820-1200% (14-21 ppbv) at 33 to 50 km. The effect on the <span class="hlt">stratospheric</span> ozone is larger following the downward transport of NOx than during and after the SPEs. The model predicts ozone losses of up to 17% and 9% at around 40 km due to transport and SPE effects, respectively.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20100031244&hterms=variability+climate&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dvariability%2Bclimate','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20100031244&hterms=variability+climate&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dvariability%2Bclimate"><span id="translatedtitle">QBO Influence on Polar <span class="hlt">Stratospheric</span> Variability in the GEOS Chemistry-Climate Model</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Hurwitz, M. M.; Oman, L. D.; Li, F.; Slong, I.-S.; Newman, P. A.; Nielsen, J. E.</p> <p>2010-01-01</p> <p>The quasi-biennial oscillation modulates the strength of both the Arctic and Antarctic <span class="hlt">stratospheric</span> vortices. Model and observational studies have found that the phase and characteristics of the quasi-biennial oscillation (QBO) contribute to the high degree of variability in the Arctic <span class="hlt">stratosphere</span> in winter. While the Antarctic <span class="hlt">stratosphere</span> is less variable, recent work has shown that Southern Hemisphere planetary wave driving increases in response to "<span class="hlt">warm</span> pool" El Nino events that are coincident with the easterly phase of the QBO. These events hasten the breakup of the Antarctic polar vortex. The Goddard Earth Observing System (GEOS) chemistry-climate model (CCM) is now capable of generating a realistic QBO, due a new parameterization of gravity wave drag. In this presentation, we will use this new model capability to assess the influence of the QBO on polar <span class="hlt">stratospheric</span> variability. Using simulations of the recent past, we will compare the modeled relationship between QBO phase and mid-winter vortex strength with the observed Holton-Tan relation, in both hemispheres. We will use simulations of the 21 St century to estimate future trends in the relationship between QBO phase and vortex strength. In addition, we will evaluate the combined influence of the QBO and El Nino/Southern Oscillation (ENSO) on the timing of the breakup of the polar <span class="hlt">stratospheric</span> vortices in the GEOS CCM. We will compare the influence of these two natural phenomena with trends in the vortex breakup associated with ozone recovery and increasing greenhouse gas concentrations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4408860','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4408860"><span id="translatedtitle"><span class="hlt">Stratospheric</span> sulfur and its implications for radiative forcing simulated by the chemistry climate model EMAC</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Brühl, C; Lelieveld, J; Tost, H; Höpfner, M; Glatthor, N</p> <p>2015-01-01</p> <p>Multiyear simulations with the atmospheric chemistry general circulation model EMAC with a microphysical modal aerosol module at high vertical resolution demonstrate that the sulfur gases COS and SO2, the latter from low-latitude and midlatitude volcanic eruptions, predominantly control the formation of <span class="hlt">stratospheric</span> aerosol. Marine dimethyl sulfide (DMS) and other SO2 sources, including strong anthropogenic emissions in China, are found to play a minor role except in the lowermost <span class="hlt">stratosphere</span>. Estimates of volcanic SO2 emissions are based on satellite observations using Total Ozone Mapping Spectrometer and Ozone Monitoring Instrument for total injected mass and Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) on Envisat or <span class="hlt">Stratospheric</span> Aerosol and Gases Experiment for the spatial distribution. The 10 year SO2 and COS data set of MIPAS is also used for model evaluation. The calculated radiative forcing of <span class="hlt">stratospheric</span> background aerosol including sulfate from COS and small contributions by DMS oxidation, and organic aerosol from biomass burning, is about 0.07W/m2. For <span class="hlt">stratospheric</span> sulfate aerosol from medium and small volcanic eruptions between 2005 and 2011 a global radiative forcing up to 0.2W/m2 is calculated, moderating climate <span class="hlt">warming</span>, while for the major Pinatubo eruption the simulated forcing reaches 5W/m2, leading to temporary climate cooling. The Pinatubo simulation demonstrates the importance of radiative feedback on dynamics, e.g., enhanced tropical upwelling, for large volcanic eruptions. PMID:25932352</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008AGUFM.U43A0047T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008AGUFM.U43A0047T"><span id="translatedtitle">Impact Of Geo-engineered Aerosols On <span class="hlt">Stratospheric</span> Chemistry And Dynamics</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tilmes, S.; Garcia, R. R.; Kinnison, D. E.; Gettelman, A.; Rasch, P. J.</p> <p>2008-12-01</p> <p>Geo-engineering schemes have been proposed to alleviate the consequences of global <span class="hlt">warming</span>; one proposed scheme is to inject sulfur into the <span class="hlt">stratosphere</span> so as to mimic the effects of large volcanic eruptions. Past volcanic eruptions have shown that strongly enhanced sulfate aerosols in the <span class="hlt">stratosphere</span> result in a higher planetary albedo, leading to surface cooling. However, the increase of sulfate aerosol surface area enhances heterogeneous reactions in the <span class="hlt">stratosphere</span> that lead to ozone loss. The potential for high Arctic ozone depletion in the context of geo-engineering is known. On the other hand, halogen compounds are now decreasing in the atmosphere as a result of the enforcement of the Montreal Protocol and its amendments, and this is expected to bring about the recovery of the ozone layer and to lessen the potential impact of aerosols. In this study we present results of calculations made with NCAR's Whole Atmosphere Community Climate Model (WACCM), focusing on the impact of Geo-engineering on <span class="hlt">stratospheric</span> chemistry and dynamics. Aside from changes in heterogeneous reactions, changes in <span class="hlt">stratospheric</span> dynamics have a significant impact on ozone. On average, changes of both chemistry and dynamics result in a slowdown of the recovery of ozone for mid- and high latitudes. An increase of ozone depletion as a result of geo-engineering was found in both polar regions for the period between 2040-2050.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2008AGUFM.A13A0204A&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2008AGUFM.A13A0204A&link_type=ABSTRACT"><span id="translatedtitle">CFC Destruction of Ozone - Major Cause of Recent Global <span class="hlt">Warming</span>!</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ashworth, R. A.</p> <p>2008-12-01</p> <p>There has been a lot of discussion about global <span class="hlt">warming</span>. Some say anthropogenic carbon dioxide (CO2) emissions caused the earth to <span class="hlt">warm</span>. Others say there is no abnormality at all, that it is just natural <span class="hlt">warming</span>. As you will see from the data presented and analyzed, a greater than normal <span class="hlt">warming</span> did occur in recent times but no measurements confirm an increase in CO2, whether anthropogenic or natural, had any effect on global temperatures. There is however, strong evidence that anthropogenic emissions of chlorofluorocarbons (CFCs) were the major cause of the recent abnormal <span class="hlt">warming</span>. CFCs have created both unnatural atmospheric cooling and <span class="hlt">warming</span> based on these facts: CFCs have destroyed ozone in the lower <span class="hlt">stratosphere</span>/ upper troposphere causing these zones in the atmosphere to cool 1.37°C from 1966 to 1998. This time span was selected to eliminate the effect of the natural solar irradiance (cooling-<span class="hlt">warming</span>) cycle effect on the earth's temperature. The loss of ozone allowed more UV light to pass through the <span class="hlt">stratosphere</span> at a sufficient rate to <span class="hlt">warm</span> the lower troposphere plus 8-3/4" of the earth by 0.48°C (1966 to 1998). Mass and energy balances show that the energy that was absorbed in the lower <span class="hlt">stratosphere</span> and upper troposphere hit the lower troposphere/earth at a sustainable level of 1.69 × 10 18 Btu more in 1998 than it did in 1966. Greater ozone depletion in the Polar Regions has caused these areas to <span class="hlt">warm</span> some two and one-half (2 1/2) times that of the average earth temperature -1.2°C versus 0.48°C. This has caused permafrost to melt, which is releasing copious quantities of methane, estimated at 100 times that of manmade CO2 release, to the atmosphere. Methane in the atmosphere slowly converts to CO2 and water vapor and its release has contributed to higher CO2 concentrations in the atmosphere. There is a temperature anomaly in Antarctica. The Signey Island landmass further north, <span class="hlt">warmed</span> like the rest of the Polar Regions; but south at Vostok, there has</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2014ACP....14.7705Z&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2014ACP....14.7705Z&link_type=ABSTRACT"><span id="translatedtitle">Evidence for an earlier greenhouse cooling effect in the <span class="hlt">stratosphere</span> before 1980 over the Northern Hemisphere</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zerefos, C. S.; Tourpali, K.; Zanis, P.; Eleftheratos, K.; Repapis, C.; Goodman, A.; Wuebbles, D.; Isaksen, I. S. A.; Luterbacher, J.</p> <p>2014-08-01</p> <p>This study provides a new look at the observed and calculated long-term temperature changes from the lower troposphere to the lower <span class="hlt">stratosphere</span> since 1958 over the Northern Hemisphere. The data sets include the NCEP/NCAR reanalysis, the Free University of Berlin (FU-Berlin) and the RICH radiosonde data sets as well as historical simulations with the CESM1-WACCM global model participating in CMIP5. The analysis is mainly based on monthly layer mean temperatures derived from geopotential height thicknesses in order to take advantage of the use of the independent FU-Berlin <span class="hlt">stratospheric</span> data set of geopotential height data since 1957. This approach was followed to extend the records for the investigation of the <span class="hlt">stratospheric</span> temperature trends to the earliest possible time. After removing the natural variability with an autoregressive multiple regression model our analysis shows that the period 1958-2011 can be divided into two distinct sub-periods of long-term temperature variability and trends: before and after 1980. By calculating trends for the summer time to reduce interannual variability, the two periods are as follows. From 1958 until 1979, a non-significant trend (0.06 ± 0.06 °C decade-1 for NCEP) and slightly cooling trends (-0.12 ± 0.06 °C decade-1 for RICH) are found in the lower troposphere. The second period from 1980 to the end of the records shows significant <span class="hlt">warming</span> (0.25 ± 0.05 °C decade-1 for both NCEP and RICH). Above the tropopause a significant cooling trend is clearly seen in the lower <span class="hlt">stratosphere</span> both in the pre-1980 period (-0.58 ± 0.17 °C decade-1 for NCEP, -0.30 ± 0.16 °C decade-1 for RICH and -0.48 ± 0.20 °C decade-1 for FU-Berlin) and the post-1980 period (-0.79 ± 0.18 °C decade-1 for NCEP, -0.66 ± 0.16 °C decade-1 for RICH and -0.82 ± 0.19 °C decade-1 for FU-Berlin). The cooling in the lower <span class="hlt">stratosphere</span> persists throughout the year from the tropics up to 60° N. At polar latitudes competing dynamical and radiative</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1994GeoRL..21.1447L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1994GeoRL..21.1447L"><span id="translatedtitle">Freezing of <span class="hlt">stratospheric</span> aerosol droplets</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Luo, Beiping; Peter, Thomas; Crutzen, Paul</p> <p></p> <p>Theoretical calculations are presented for homogeneous and heterogeneous freezing of sulfuric acid droplets under <span class="hlt">stratospheric</span> conditions, based on classical nucleation theory. In contrast to previous results it is shown that a prominent candidate for freezing, sulfuric acid tetrahydrate (SAT ≡ H2SO4·4H2O), does not freeze homogeneously. The theoretical results limit the homogeneous freezing rate at 200 K to much less than 1 cm-3s-1, a value that may be estimated from bulk phase laboratory experiments. This suggests that the experimental value is likely to be a measure of heterogeneous, not homogeneous nucleation. Thus, under statospheric conditions, freezing of SAT can only occur in the presence of suitable nuclei; however, even for heterogeneous nucleation experimental results impose strong constraints. Since a nitric acid trihydrate (NAT) embryo probably needs a solid body for nucleation, these results put an important constraint on the theory of NAT formation in polar <span class="hlt">stratospheric</span> clouds.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19940033096','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19940033096"><span id="translatedtitle"><span class="hlt">Stratospheric</span> emissions effects database development</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Baughcum, Steven L.; Henderson, Stephen C.; Hertel, Peter S.; Maggiora, Debra R.; Oncina, Carlos A.</p> <p>1994-01-01</p> <p>This report describes the development of a <span class="hlt">stratospheric</span> emissions effects database (SEED) of aircraft fuel burn and emissions from projected Year 2015 subsonic aircraft fleets and from projected fleets of high-speed civil transports (HSCT's). This report also describes the development of a similar database of emissions from Year 1990 scheduled commercial passenger airline and air cargo traffic. The objective of this work was to initiate, develop, and maintain an engineering database for use by atmospheric scientists conducting the Atmospheric Effects of <span class="hlt">Stratospheric</span> Aircraft (AESA) modeling studies. Fuel burn and emissions of nitrogen oxides (NO(x) as NO2), carbon monoxide, and hydrocarbons (as CH4) have been calculated on a 1-degree latitude x 1-degree longitude x 1-kilometer altitude grid and delivered to NASA as electronic files. This report describes the assumptions and methodology for the calculations and summarizes the results of these calculations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20030105974','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20030105974"><span id="translatedtitle">Artemis: A <span class="hlt">Stratospheric</span> Planet Finder</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Ford, H. C.; Petro, L. D.; Burrows, C.; Ftaclas, C.; Roggemann, M. C.; Trauger, J. T.</p> <p>2003-01-01</p> <p>The near-space environment of the <span class="hlt">stratosphere</span> is far superior to terrestrial sites for optical and infrared observations. New balloon technologies will enable flights and safe recovery of 2-ton payloads at altitudes of 35 km for 100 days and longer. The combination of long flights and superb observing conditions make it possible to undertake science programs that otherwise could only be done from orbit. We propose to fly an "Ultra-Hubble" <span class="hlt">Stratospheric</span> Telescope (UHST) equipped with a coronagraphic camera and active optics at 35 km to search for planets around 200 of the nearest stars. This ULDB mission will establish the frequency of solar-type planetary systems, and provide targets to search for earth-like planets.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/6952854','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/6952854"><span id="translatedtitle"><span class="hlt">Stratospheric</span> emissions effects database development</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Baughcum, S.L.; Henderson, S.C.; Hertel, P.S.; Maggiora, D.R.; Oncina, C.A.</p> <p>1994-07-01</p> <p>This report describes the development of a <span class="hlt">stratospheric</span> emissions effects database (SEED) of aircraft fuel burn and emissions from projected Year 2015 subsonic aircraft fleets and from projected fleets of high-speed civil transports (HSCT's). This report also describes the development of a similar database of emissions from Year 1990 scheduled commercial passenger airline and air cargo traffic. The objective of this work was to initiate, develop, and maintain an engineering database for use by atmospheric scientists conducting the Atmospheric Effects of <span class="hlt">Stratospheric</span> Aircraft (AESA) modeling studies. Fuel burn and emissions of nitrogen oxides (NO(x) as NO2), carbon monoxide, and hydrocarbons (as CH4) have been calculated on a 1-degree latitude x 1-degree longitude x 1-kilometer altitude grid and delivered to NASA as electronic files. This report describes the assumptions and methodology for the calculations and summarizes the results of these calculations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20110005651','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20110005651"><span id="translatedtitle">Ices in Titan's Lower <span class="hlt">Stratosphere</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Anderson, Carrie</p> <p>2010-01-01</p> <p>Analyses of Cassini CIRS far-infrared limb spectra of Titan at 15N, 15S, and 58S reveal a broad emission feature between 70 and 270/cm, restricted to altitudes between 60 and 100 km. This emission feature is chemically different from Titan's photochemical aerosol, which has an emission feature peak around 145 cm-1. The shape of the observed broad emission feature resembles a mixture of the solid component of the two most abundant nitrites in Titan's <span class="hlt">stratosphere</span>, that of HCN and HC3N. Following the saturation vapor pressure vertical profiles of HCN and HC3N, the 60 to 100 km altitude range corresponds closely to the vertical location where these nitriles are expected to condense out and form small, suspended ice particles. This is the first time ices in Titan's <span class="hlt">stratosphere</span> have been identified at latitudes south of 50N. Results and physical implications will be discussed.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li class="active"><span>15</span></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_15 --> <div id="page_16" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li class="active"><span>16</span></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="301"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013JGRD..118.9658G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013JGRD..118.9658G"><span id="translatedtitle">Temperature trends in the tropical upper troposphere and lower <span class="hlt">stratosphere</span>: Connections with sea surface temperatures and implications for water vapor and ozone</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Garfinkel, C. I.; Waugh, D. W.; Oman, L. D.; Wang, L.; Hurwitz, M. M.</p> <p>2013-09-01</p> <p>Satellite observations and chemistry-climate model experiments are used to understand the zonal structure of tropical lower <span class="hlt">stratospheric</span> temperature, water vapor, and ozone trends. The <span class="hlt">warming</span> in the tropical upper troposphere over the past 30 years is strongest near the Indo-Pacific <span class="hlt">warm</span> pool, while the <span class="hlt">warming</span> trend in the western and central Pacific is much weaker. In the lower <span class="hlt">stratosphere</span>, these trends are reversed: the historical cooling trend is strongest over the Indo-Pacific <span class="hlt">warm</span> pool and is weakest in the western and central Pacific. These zonal variations are stronger than the zonal-mean response in boreal winter. Targeted experiments with a chemistry-climate model are used to demonstrate that sea surface temperature (hereafter SST) trends are driving the zonal asymmetry in upper tropospheric and lower <span class="hlt">stratospheric</span> tropical temperature trends. <span class="hlt">Warming</span> SSTs in the Indian Ocean and in the <span class="hlt">warm</span> pool region have led to enhanced moist heating in the upper troposphere, and in turn to a Gill-like response that extends into the lower <span class="hlt">stratosphere</span>. The anomalous circulation has led to zonal structure in the ozone and water vapor trends near the tropopause, and subsequently to less water vapor entering the <span class="hlt">stratosphere</span>. The radiative impact of these changes in trace gases is smaller than the direct impact of the moist heating. Projected future SSTs appear to drive a temperature and water vapor response whose zonal structure is similar to the historical response. In the lower <span class="hlt">stratosphere</span>, the changes in water vapor and temperature due to projected future SSTs are of similar strength to, though slightly weaker than, that due directly to projected future CO2, ozone, and methane.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20140013023','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20140013023"><span id="translatedtitle">Temperature Trends in the Tropical Upper Troposphere and Lower <span class="hlt">Stratosphere</span>: Connections with Sea Surface Temperatures and Implications for Water Vapor and Ozone</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Garfinkel, C. I.; Waugh, D. W.; Oman, L. D.; Wang, L.; Hurwitz, M. M.</p> <p>2013-01-01</p> <p>Satellite observations and chemistry-climate model experiments are used to understand the zonal structure of tropical lower <span class="hlt">stratospheric</span> temperature, water vapor, and ozone trends. The <span class="hlt">warming</span> in the tropical upper troposphere over the past 30 years is strongest near the Indo-Pacific <span class="hlt">warm</span> pool, while the <span class="hlt">warming</span> trend in the western and central Pacific is much weaker. In the lower <span class="hlt">stratosphere</span>, these trends are reversed: the historical cooling trend is strongest over the Indo-Pacific <span class="hlt">warm</span> pool and is weakest in the western and central Pacific. These zonal variations are stronger than the zonal-mean response in boreal winter. Targeted experiments with a chemistry-climate model are used to demonstrate that sea surface temperature (hereafter SST) trends are driving the zonal asymmetry in upper tropospheric and lower <span class="hlt">stratospheric</span> tropical temperature trends. <span class="hlt">Warming</span> SSTs in the Indian Ocean and in the <span class="hlt">warm</span> pool region have led to enhanced moist heating in the upper troposphere, and in turn to a Gill-like response that extends into the lower <span class="hlt">stratosphere</span>. The anomalous circulation has led to zonal structure in the ozone and water vapor trends near the tropopause, and subsequently to less water vapor entering the <span class="hlt">stratosphere</span>. The radiative impact of these changes in trace gases is smaller than the direct impact of the moist heating. Projected future SSTs appear to drive a temperature and water vapor response whose zonal structure is similar to the historical response. In the lower <span class="hlt">stratosphere</span>, the changes in water vapor and temperature due to projected future SSTs are of similar strength to, though slightly weaker than, that due directly to projected future CO2, ozone, and methane.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://eric.ed.gov/?q=warm+AND+up&pg=7&id=EJ404495','ERIC'); return false;" href="http://eric.ed.gov/?q=warm+AND+up&pg=7&id=EJ404495"><span id="translatedtitle"><span class="hlt">Warm</span> Up with Skill.</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Hoyle, R. J.; Smith, Robert F.</p> <p>1989-01-01</p> <p>Too little time is often spent on <span class="hlt">warm</span>-up activities in the school or recreation class. <span class="hlt">Warm</span>-ups are often perfunctory and unimaginative. Several suggestions are made for <span class="hlt">warm</span>-up activities that incorporate both previously learned and new skills, while preparing the body for more vigorous activity. (IAH)</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015GeoRL..42.4989M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015GeoRL..42.4989M"><span id="translatedtitle">Inability of <span class="hlt">stratospheric</span> sulfate aerosol injections to preserve the West Antarctic Ice Sheet</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>McCusker, K. E.; Battisti, D. S.; Bitz, C. M.</p> <p>2015-06-01</p> <p>Injection of sulfate aerosols into the <span class="hlt">stratosphere</span> has the potential to reduce the climate impacts of global <span class="hlt">warming</span>, including sea level rise (SLR). However, changes in atmospheric and oceanic circulation that can significantly influence the rate of basal melting of Antarctic marine ice shelves and the associated SLR have not previously been considered. Here we use a fully coupled global climate model to investigate whether rapidly increasing <span class="hlt">stratospheric</span> sulfate aerosol concentrations after a period of global <span class="hlt">warming</span> could preserve Antarctic ice sheets by cooling subsurface ocean temperatures. We contrast this climate engineering method with an alternative strategy in which all greenhouse gases (GHG) are returned to preindustrial levels. We find that the rapid addition of a <span class="hlt">stratospheric</span> aerosol layer does not effectively counteract surface and upper level atmospheric circulation changes caused by increasing GHGs, resulting in continued upwelling of <span class="hlt">warm</span> water in proximity of ice shelves, especially in the vicinity of the already unstable Pine Island Glacier in West Antarctica. By contrast, removal of GHGs restores the circulation, yielding relatively cooler subsurface ocean temperatures to better preserve West Antarctica.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20070025103&hterms=warming&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dwarming','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20070025103&hterms=warming&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dwarming"><span id="translatedtitle">Simulations of Dynamics and Transport during the September 2002 Antarctic Major <span class="hlt">Warming</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Manney, Gloria L.; Sabutis, Joseph L.; Allen, Douglas R.; Lahoz, Willian A.; Scaife, Adam A.; Randall, Cora E.; Pawson, Steven; Naujokat, Barbara; Swinbank, Richard</p> <p>2005-01-01</p> <p>A mechanistic model simulation initialized on 14 September 2002, forced by 100-hPa geopotential heights from Met Office analyses, reproduced the dynamical features of the 2002 Antarctic major <span class="hlt">warming</span>. The vortex split on approx.25 September; recovery after the <span class="hlt">warming</span>, westward and equatorward tilting vortices, and strong baroclinic zones in temperature associated with a dipole pattern of upward and downward vertical velocities were all captured in the simulation. Model results and analyses show a pattern of strong upward wave propagation throughout the <span class="hlt">warming</span>, with zonal wind deceleration throughout the <span class="hlt">stratosphere</span> at high latitudes before the vortex split, continuing in the middle and upper <span class="hlt">stratosphere</span> and spreading to lower latitudes after the split. Three-dimensional Eliassen-Palm fluxes show the largest upward and poleward wave propagation in the 0(deg)-90(deg)E sector prior to the vortex split (coincident with the location of strongest cyclogenesis at the model's lower boundary), with an additional region of strong upward propagation developing near 180(deg)-270(deg)E. These characteristics are similar to those of Arctic wave-2 major <span class="hlt">warmings</span>, except that during this <span class="hlt">warming</span>, the vortex did not split below approx.600 K. The effects of poleward transport and mixing dominate modeled trace gas evolution through most of the mid- to high-latitude <span class="hlt">stratosphere</span>, with a core region in the lower-<span class="hlt">stratospheric</span> vortex where enhanced descent dominates and the vortex remains isolated. Strongly tilted vortices led to low-latitude air overlying vortex air, resulting in highly unusual trace gas profiles. Simulations driven with several meteorological datasets reproduced the major <span class="hlt">warming</span>, but in others, stronger latitudinal gradients at high latitudes at the model boundary resulted in simulations without a complete vortex split in the midstratosphere. Numerous tests indicate very high sensitivity to the boundary fields, especially the wave-2 amplitude. Major <span class="hlt">warmings</span></p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/23192146','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/23192146"><span id="translatedtitle">The mystery of recent <span class="hlt">stratospheric</span> temperature trends.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Thompson, David W J; Seidel, Dian J; Randel, William J; Zou, Cheng-Zhi; Butler, Amy H; Mears, Carl; Osso, Albert; Long, Craig; Lin, Roger</p> <p>2012-11-29</p> <p>A new data set of middle- and upper-<span class="hlt">stratospheric</span> temperatures based on reprocessing of satellite radiances provides a view of <span class="hlt">stratospheric</span> climate change during the period 1979-2005 that is strikingly different from that provided by earlier data sets. The new data call into question our understanding of observed <span class="hlt">stratospheric</span> temperature trends and our ability to test simulations of the <span class="hlt">stratospheric</span> response to emissions of greenhouse gases and ozone-depleting substances. Here we highlight the important issues raised by the new data and suggest how the climate science community can resolve them. PMID:23192146</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19990099126','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19990099126"><span id="translatedtitle"><span class="hlt">Stratospheric</span> Temperature Changes: Observations and Model Simulations</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Ramaswamy, V.; Chanin, M.-L.; Angell, J.; Barnett, J.; Gaffen, D.; Gelman, M.; Keckhut, P.; Koshelkov, Y.; Labitzke, K.; Lin, J.-J. R.</p> <p>1999-01-01</p> <p>This paper reviews observations of <span class="hlt">stratospheric</span> temperatures that have been made over a period of several decades. Those observed temperatures have been used to assess variations and trends in <span class="hlt">stratospheric</span> temperatures. A wide range of observation datasets have been used, comprising measurements by radiosonde (1940s to the present), satellite (1979 - present), lidar (1979 - present) and rocketsonde (periods varying with location, but most terminating by about the mid-1990s). In addition, trends have also been assessed from meteorological analyses, based on radiosonde and/or satellite data, and products based on assimilating observations into a general circulation model. Radiosonde and satellite data indicate a cooling trend of the annual-mean lower <span class="hlt">stratosphere</span> since about 1980. Over the period 1979-1994, the trend is 0.6K/decade. For the period prior to 1980, the radiosonde data exhibit a substantially weaker long-term cooling trend. In the northern hemisphere, the cooling trend is about 0.75K/decade in the lower <span class="hlt">stratosphere</span>, with a reduction in the cooling in mid-<span class="hlt">stratosphere</span> (near 35 km), and increased cooling in the upper <span class="hlt">stratosphere</span> (approximately 2 K per decade at 50 km). Model simulations indicate that the depletion of lower <span class="hlt">stratospheric</span> ozone is the dominant factor in the observed lower <span class="hlt">stratospheric</span> cooling. In the middle and upper <span class="hlt">stratosphere</span> both the well-mixed greenhouse gases (such as CO) and ozone changes contribute in an important manner to the cooling.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015DPS....4740008S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015DPS....4740008S"><span id="translatedtitle">Seasonal evolution of Saturn's <span class="hlt">stratosphere</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sylvestre, Melody; Fouchet, Thierry; Spiga, Aymeric; Guerlet, Sandrine</p> <p>2015-11-01</p> <p>The exceptional duration of the Cassini-Huygens mission enables unprecedented study of Saturn's atmospheric dynamics and chemistry. In Saturn's <span class="hlt">stratosphere</span> (from 20 hPa to 10-4 hPa), photochemical and radiative timescales are in the same order as Saturn's revolution period (29.5 years). Consequently, the large seasonal insolation variations experienced by this planet are expected to influence significantly temperatures and abundances of photochemical by-products in this region. We investigate the seasonal evolution of Saturn's <span class="hlt">stratosphere</span> by measuring meridional and seasonal variations (from 2005 to 2012) of temperature and C2H6, C2H2, and C3H8 abundances using Cassini/CIRS limb observations. We complete this study with the development of a GCM (Global Climate Model), in order to understand the physical processes behind this seasonal evolution.The analysis of the CIRS limb observations show that the lower and upper <span class="hlt">stratospheres</span> do not exhibit the same trends in their seasonal variations, especially for temperature. In the lower <span class="hlt">stratosphere</span>, the seasonal temperature contrast is maximal (at 1 hPa) and can be explained by the radiative contributions included in our GCM. In contrast, upper <span class="hlt">stratospheric</span> temperatures (at 0.01 hPa) are constant from northern winter to spring, at odds with our GCM predictions. This behavior indicates that other physical processes such as gravity waves breaking may be at play. At 1 hPa, C2H6, C2H2, and C3H8 abundances exhibit a striking seasonal stability, consistently with the predictions of the photochemical models of Moses and Greathouse, 2005 and Hue et al., 2015. However, the meridional distributions of these species do not follow the predicted trends, which gives insight on atmospheric dynamics. We perform numerical simulations with the GCM to better understand dynamical phenomena in Saturn's atmosphere. We investigate how the large insolation variations induced by the shadow of the rings influence temperatures and atmospheric</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19850017663','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19850017663"><span id="translatedtitle">Development of algorithms for using satellite meteorological data sets to study global transport of <span class="hlt">stratospheric</span> aerosols and ozone</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Want, P. H.; Deepak, A.</p> <p>1985-01-01</p> <p>The utilization of <span class="hlt">stratospheric</span> aerosol and ozone measurements obtained from the NASA developed SAM II and SAGE satellite instruments were investigated for their global scale transports. The <span class="hlt">stratospheric</span> aerosols showed that during the <span class="hlt">stratospheric</span> <span class="hlt">warming</span> of the winter 1978 to 1979, the distribution of the zonal mean aerosol extinction ratio in the northern high latitude exhibited distinct changes. Dynamic processes might have played an important role in maintenance role in maintenance of this zonal mean distribution. As to the <span class="hlt">stratospheric</span> ozone, large poleward ozone transports are shown to occur in the altitude region from 24 km to 38 km near 55N during this <span class="hlt">warming</span>. This altitude region is shown to be a transition region of the phase relationship between ozone and temperature waves from an in-phase one above 38 km. It is shown that the ozone solar heating in the upper <span class="hlt">stratosphere</span> might lead to enhancement of the damping rate of the planetary waves due to infrared radiation alone in agreement with theoretical analyses and an earlier observational study.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009ACPD....9.9693M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009ACPD....9.9693M"><span id="translatedtitle">Satellite observations and modelling of transport in the upper troposphere through the lower mesosphere during the 2006 major <span class="hlt">stratospheric</span> sudden arming</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Manney, G. L.; Harwood, R. S.; MacKenzie, I. A.; Minschwaner, K.; Allen, D. R.; Santee, M. L.; Walker, K. A.; Hegglin, M. I.; Lambert, A.; Pumphrey, H. C.; Bernath, P. F.; Boone, C. D.; Schwartz, M. J.; Livesey, N. J.; Daffer, W. H.; Fuller, R. A.</p> <p>2009-04-01</p> <p>An unusually strong and prolonged <span class="hlt">stratospheric</span> sudden <span class="hlt">warming</span> (SSW) in January 2006 was the first major SSW for which globally distributed long-lived trace gas data are available covering the upper troposphere through the lower mesosphere. We use Aura Microwave Limb Sounder (MLS), Atmospheric Chemistry Experiment-Fourier Transform Spectrometer (ACE-FTS) data, the SLIMCAT Chemistry Transport Model (CTM), and assimilated meteorological analyses to provide a comprehensive picture of transport during this event. The upper tropospheric ridge that triggered the SSW was associated with an elevated tropopause and layering in trace gas profiles in conjunction with <span class="hlt">stratospheric</span> and tropospheric intrusions. Anomalous poleward transport (with corresponding quasi-isentropic troposphere-to-<span class="hlt">stratosphere</span> exchange at the lowest levels studied) in the region over the ridge extended well into the lower <span class="hlt">stratosphere</span>. In the middle and upper <span class="hlt">stratosphere</span>, the breakdown of the polar vortex transport barrier was seen in a signature of rapid, widespread mixing in trace gases, including CO, H2O, CH4 and N2O. The vortex broke down slightly later and more slowly in the lower than in the middle <span class="hlt">stratosphere</span>. In the middle and lower <span class="hlt">stratosphere</span>, small remnants with trace gas values characteristic of the pre-SSW vortex lingered through the weak and slow recovery of the vortex. The upper <span class="hlt">stratospheric</span> vortex quickly reformed, and, as enhanced diabatic descent set in, CO descended into this strong vortex, echoing the fall vortex development. Trace gas evolution in the SLIMCAT CTM agrees well with that in the satellite trace gas data from the upper troposphere through the middle <span class="hlt">stratosphere</span>. In the upper <span class="hlt">stratosphere</span> and lower mesosphere, the SLIMCAT simulation does not capture the strong descent of mesospheric CO and H2O values into the reformed vortex; poor CTM performance in the upper <span class="hlt">stratosphere</span> and lower mesosphere results primarily from biases in the diabatic descent in assimilated</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016ClDy..tmp..333R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016ClDy..tmp..333R"><span id="translatedtitle">Tracking the delayed response of the northern winter <span class="hlt">stratosphere</span> to ENSO using multi reanalyses and model simulations</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ren, Rongcai; Rao, Jian; Wu, Guoxiong; Cai, Ming</p> <p>2016-06-01</p> <p>The concurrent effects of the El Niño-Southern Oscillation (ENSO) on the northern winter <span class="hlt">stratosphere</span> have been widely recognized; however, the delayed effects of ENSO in the next winter after mature ENSO have yet to be confirmed in multi reanalyses and model simulations. This study uses three reanalysis datasets, a long-term fully coupled model simulation, and a high-top general circulation model to examine ENSO's delayed effects in the <span class="hlt">stratosphere</span>. The <span class="hlt">warm</span>-minus-cold composite analyses consistently showed that, except those quick-decaying quasi-biennial ENSO events that reverse signs during July-August-September (JAS) in their decay years, ENSO events particularly those quasi-quadrennial (QQ) that persist through JAS, always have a significant effect on the extratropical <span class="hlt">stratosphere</span> in both the concurrent winter and the next winter following mature ENSO. During the concurrent winter, the QQ ENSO-induced Pacific-North American (PNA) pattern corresponds to an anomalous wavenumber-1 from the upper troposphere to the <span class="hlt">stratosphere</span>, which acts to intensify/weaken the climatological wave pattern during <span class="hlt">warm</span>/cold ENSO. Associated with the zonally quasi-homogeneous tropical forcing in spring of the QQ ENSO decay years, there appear persistent and zonally quasi-homogeneous temperature anomalies in the midlatitudes from the upper troposphere to the lower <span class="hlt">stratosphere</span> until summer. With the reduction in ENSO forcing and the PNA responses in the following winter, an anomalous wavenumber-2 prevails in the extratropics. Although the anomalous wave flux divergence in the upper <span class="hlt">stratospheric</span> layer is still dominated by wavenumber-1, it is mainly caused by wavenumber-2 in the lower <span class="hlt">stratosphere</span>. However, the wavenumber-2 activity in the next winter is always underestimated in the model simulations, and wavenumber-1 activity dominates in both winters.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012Icar..221..560F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012Icar..221..560F"><span id="translatedtitle">The origin and evolution of Saturn’s 2011-2012 <span class="hlt">stratospheric</span> vortex</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Fletcher, Leigh N.; Hesman, B. E.; Achterberg, R. K.; Irwin, P. G. J.; Bjoraker, G.; Gorius, N.; Hurley, J.; Sinclair, J.; Orton, G. S.; Legarreta, J.; García-Melendo, E.; Sánchez-Lavega, A.; Read, P. L.; Simon-Miller, A. A.; Flasar, F. M.</p> <p>2012-11-01</p> <p>The planet-encircling springtime storm in Saturn’s troposphere (December 2010-July 2011, Fletcher, L.N. et al. [2011]. Science 332, 1413-1414; Sánchez-Lavega, A. et al. [2011]. Nature 475, 71-74; Fischer, G. et al. [2011]. Nature 475, 75-77) produced dramatic perturbations to <span class="hlt">stratospheric</span> temperatures, winds and composition at mbar pressures that persisted long after the tropospheric disturbance had abated. Thermal infrared (IR) spectroscopy from the Cassini Composite Infrared Spectrometer (CIRS), supported by ground-based IR imaging from the VISIR instrument on the Very Large Telescope and the MIRSI instrument on NASA’s IRTF, is used to track the evolution of a large, hot <span class="hlt">stratospheric</span> anticyclone between January 2011 and March 2012. The evolutionary sequence can be divided into three phases: (I) the formation and intensification of two distinct <span class="hlt">warm</span> airmasses near 0.5 mbar between 25 and 35°N (B1 and B2) between January-April 2011, moving westward with different zonal velocities, B1 residing directly above the convective tropospheric storm head; (II) the merging of the <span class="hlt">warm</span> airmasses to form the large single ‘<span class="hlt">stratospheric</span> beacon’ near 40°N (B0) between April and June 2011, disassociated from the storm head and at a higher pressure (2 mbar) than the original beacons, a downward shift of 1.4 scale heights (approximately 85 km) post-merger; and (III) the mature phase characterised by slow cooling (0.11 ± 0.01 K/day) and longitudinal shrinkage of the anticyclone since July 2011. Peak temperatures of 221.6 ± 1.4 K at 2 mbar were measured on May 5th 2011 immediately after the merger, some 80 K warmer than the quiescent surroundings. From July 2011 to the time of writing, B0 remained as a long-lived stable <span class="hlt">stratospheric</span> phenomenon at 2 mbar, moving west with a near-constant velocity of 2.70 ± 0.04 deg/day (-24.5 ± 0.4 m/s at 40°N relative to System III longitudes). No perturbations to visible clouds and hazes were detected during this period. With no</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016JGRD..121.3776E','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016JGRD..121.3776E"><span id="translatedtitle">Troposphere-<span class="hlt">stratosphere</span> dynamical coupling in the southern high latitudes and its linkage to the Amundsen Sea</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>England, Mark R.; Shaw, Tiffany A.; Polvani, Lorenzo M.</p> <p>2016-04-01</p> <p>Extremes in the distribution of Southern Hemisphere <span class="hlt">stratospheric</span> heat flux are connected simultaneously to anomalous high-latitude tropospheric weather patterns in reanalysis, consistent with results from the Northern Hemisphere. The dynamical links are revealed using a metric based on extreme <span class="hlt">stratospheric</span> planetary-scale wave heat flux events, defined as the 10th and 90th percentiles of the daily high-latitude wave 1 heat flux distribution at 50 hPa. We show extreme negative (positive) heat flux events are linked to a westward (eastward) shift in the Amundsen Sea Low and anomalous <span class="hlt">warming</span> (cooling) over the Amundsen Bellingshausen Seas in reanalysis data. Since coupling to the <span class="hlt">stratosphere</span> via planetary waves has significant impacts on the tropospheric circulation of both hemispheres, it is important to understand which coupled climate models can reproduce this phenomenon. The heat flux metric is used to evaluate troposphere-<span class="hlt">stratosphere</span> coupling in models participating in the Coupled Model Intercomparison Project Phase 5 (CMIP5) and compare their performance across hemispheres. The results show that models with a degraded representation of <span class="hlt">stratospheric</span> extremes exhibit robust biases in tropospheric sea level pressure variability over the Antarctic Peninsula. Models which fail to capture the extremes in <span class="hlt">stratospheric</span> heat flux, significantly underestimate the variance of the distribution of mean sea level pressure anomalies over Western Antarctica.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20120013522','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20120013522"><span id="translatedtitle">The Evolution and Fate of Saturn's <span class="hlt">Stratospheric</span> Vortex: Infrared Spectroscopy from Cassini</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Fletcher, Leigh N.; Hesman, B. E.; Arhterberg, R. K.; Bjoraker, G.; Irwin, P. G. J.; Hurley, J.; Sinclair, J.; Gorius, N.; Orton, G. S.; Read, P. L.; Simon-Miller, A. A.; Flasar, F. M.</p> <p>2012-01-01</p> <p>The planet-encircling springtime storm in Saturn's troposphere (December 2010-July 2011) produced dramatic perturbations to <span class="hlt">stratospheric</span> temperatures, winds and composition at mbar pressures that persisted long after the tropospheric disturbance had abated. Observations from the Cassini Composite Infrared Spectrometer (CIRS), supported by ground-based imaging from the VISIR instrument on the Very Large Telescope,is used to track the evolution of a large, hot <span class="hlt">stratospheric</span> anticyclone between January 2011 and the present day. The evolutionary sequence can be divided into three phases: (I) the formation and intensification of two distinct <span class="hlt">warm</span> airmasses near 0.5 mbar between 25 and 35N (one residing directly above the convective storm head) between January-April 2011, moving westward with different zonal velocities; (II) the merging of the <span class="hlt">warm</span> airmasses to form the large single '<span class="hlt">stratospheric</span> beacon' near 40N between April and June 2011, dissociated from the storm head and at a higher pressure (2 mbar) than the original beacons; and (III) the mature phase characterized by slow cooling and longitudinal shrinkage of the anticyclone since July 2011, moving west with a near-constant velocity of 2.70+/-0.04 deg/day (-24.5+/-0.4 m/s at 40N). Peak temperatures of 220 K at 2 mbar were measured on May 5th 2011 immediately after the merger, some 80 K warmer than the quiescent surroundings. Thermal winds hear calculations in August 2011 suggest clockwise peripheral velocities of 200400 mls at 2 mbar, defining a peripheral collar with a width of 65 degrees longitude (50,000 km in diameter) and 25 degrees latitude. <span class="hlt">Stratospheric</span> acetylene (C2H2) was uniformly enhanced by a factor of three within the vortex, whereas ethane (C2H6) remained unaffected. We will discuss the thermal and chemical characteristics of Saturn's beacon in its mature phase, and implications for <span class="hlt">stratospheric</span> vortices on other giant planets.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19920005296','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19920005296"><span id="translatedtitle">Radiative flux measurements in the <span class="hlt">stratosphere</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Valero, Francisco P. J.</p> <p>1990-01-01</p> <p>The objective is to determine how the <span class="hlt">stratospheric</span> tropospheric exchange of water vapor is affected by the interaction of solar (visible) and planetary (infrared) radiation with tropical cumulonimbus anvils. This research involves field measurements from the ER-2 aircraft as well as radiative transfer modelling to determine heating and cooling rates and profiles that directly affect the exchange between the troposphere and the <span class="hlt">stratosphere</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://eric.ed.gov/?q=Halogens&pg=2&id=EJ391165','ERIC'); return false;" href="http://eric.ed.gov/?q=Halogens&pg=2&id=EJ391165"><span id="translatedtitle">Changing Composition of the Global <span class="hlt">Stratosphere</span>.</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>McElroy, Michael B.; Salawitch, Ross J.</p> <p>1989-01-01</p> <p>Discusses the chemistry of the <span class="hlt">stratosphere</span> at mid-latitudes, the Antarctic phenomenon, and temporal trends in ozone levels. Includes equations, diagrams of the global distribution of ozone, and halogen growth projections. Concludes that studies of <span class="hlt">stratospheric</span> ozone demonstrate that the global environment is fragile and is impacted by human…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFMGC13I0788L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFMGC13I0788L"><span id="translatedtitle">Arctic <span class="hlt">stratospheric</span> sulphur injections: radiative forcings and cloud responses</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lohmann, U.; Gasparini, B.; Miriam, K.; Kravitz, B.; Rasch, P. J.</p> <p>2014-12-01</p> <p>Observations and climate projections show a high sensitivity of the Arctic climate to the increase in greenhouse gas emissions, known as the polar amplification. This study evaluates the options of counteracting the rising polar temperatures by <span class="hlt">stratospheric</span> sulphur injections in the Northern Hemisphere high latitudes.10 Mt of sulphur dioxide are emitted in a point emission source setup centred at the 100 hPa pressure level over Svalbard island (80°N,15°E). We perform simulations with the general circulation models ECHAM5, ECHAM6, and GISS ModelE. We study pulsed emission simulations that differ among themselves by the injection starting date (March-September), injection length (1, 30, or 90 day emission period), and the vertical resolution of the model (for ECHAM6). We find injections in April to be the most efficient in terms of the shortwave radiative forcing at the top-of-the atmosphere over the Arctic region. The distribution of sulphate aerosol spreads out beyond the injection region, with a significant share reaching the Southern Hemisphere. Results from ModelE show high latitude injections could counteract the spring and summer temperature increase due to higher atmospheric CO2 concentrations. Preliminary results with a more realistic description of clouds in ECHAM-HAM reveal a complex pattern of responses, most notably: a decrease in Northern Hemisphere cirrus clouds strengthening the effect of <span class="hlt">stratospheric</span> aerosols in ECHAM5 a decrease in low-level clouds over the Arctic increasing the incoming solar radiation and causing a net positive radiative balance cirrus clouds are resilient to <span class="hlt">stratospheric</span> sulphur injections in the absence of sulphate <span class="hlt">warming</span></p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1987AdSpR...7...73M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1987AdSpR...7...73M"><span id="translatedtitle">Background <span class="hlt">stratospheric</span> aerosol reference model</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>McCormick, M. P.; Wang, Pi-Huan</p> <p></p> <p>Nearly global SAGE I satellite observations in the nonvolcanic period from March 1979 to February 1980 are used to produce a reference background <span class="hlt">stratospheric</span> aerosol optical model. Zonally average profiles of the 1.0-micron aerosol extinction for the tropics, midlatitudes, and high latitudes for both hemispheres are given in graphical and tabulated form for the different seasons. A third order polynomial fit to the vertical profile data set is used to derive analytic expressions for the seasonal global means and the yearly global mean. The results have application to the simulation of atmospheric radiative transfer and radiance calculations in atmospheric remote sensing.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010sf2a.conf....7H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010sf2a.conf....7H"><span id="translatedtitle"><span class="hlt">Stratospheric</span> Observatory for Infrared Astronomy</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hamidouche, M.; Young, E.; Marcum, P.; Krabbe, A.</p> <p>2010-12-01</p> <p>We present one of the new generations of observatories, the <span class="hlt">Stratospheric</span> Observatory For Infrared Astronomy (SOFIA). This is an airborne observatory consisting of a 2.7-m telescope mounted on a modified Boeing B747-SP airplane. Flying at an up to 45,000 ft (14 km) altitude, SOFIA will observe above more than 99 percent of the Earth's atmospheric water vapor allowing observations in the normally obscured far-infrared. We outline the observatory capabilities and goals. The first-generation science instruments flying on board SOFIA and their main astronomical goals are also presented.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20040031759&hterms=kawa&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dkawa','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20040031759&hterms=kawa&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dkawa"><span id="translatedtitle">Total Ozone Prediction: <span class="hlt">Stratospheric</span> Dynamics</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Jackman, Charles H.; Kawa, S. Ramdy; Douglass, Anne R.</p> <p>2003-01-01</p> <p>The correct prediction of total ozone as a function of latitude and season is extremely important for global models. This exercise tests the ability of a particular model to simulate ozone. The ozone production (P) and loss (L) will be specified from a well- established global model and will be used in all GCMs for subsequent prediction of ozone. This is the "B-3 Constrained Run" from M&MII. The exercise mostly tests a model <span class="hlt">stratospheric</span> dynamics in the prediction of total ozone. The GCM predictions will be compared and contrasted with TOMS measurements.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li class="active"><span>16</span></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_16 --> <div id="page_17" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li class="active"><span>17</span></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="321"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19990089301&hterms=NaSH&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3DNaSH','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19990089301&hterms=NaSH&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3DNaSH"><span id="translatedtitle">Quantifying the Wave Driving of the <span class="hlt">Stratosphere</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Newman, Paul A.; Nash, Eric R.</p> <p>1999-01-01</p> <p>The zonal mean eddy heat flux is directly proportional to the wave activity that propagates from the troposphere into the <span class="hlt">stratosphere</span>. This quantity is a simple eddy diagnostic which is easily calculated from conventional meteorological analyses. Because this "wave driving" of the <span class="hlt">stratosphere</span> has a strong impact on the <span class="hlt">stratospheric</span> temperature, it is necessary to compare the impact of the flux with respect to <span class="hlt">stratospheric</span> radiative changes caused by greenhouse gas changes. Hence, we must understand the precision and accuracy of the heat flux derived from our global meteorological analyses. Herein, we quantify the <span class="hlt">stratospheric</span> heat flux using five different meteorological analyses, and show that there are 30% differences between these analyses during the disturbed conditions of the northern hemisphere winter. Such large differences result from the planetary differences in the stationary temperature and meridional wind fields. In contrast, planetary transient waves show excellent agreement amongst these five analyses, and this transient heat flux appears to have a long term downward trend.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19990014075&hterms=Montreal+protocol&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3D%2528Montreal%2Bprotocol%2529','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19990014075&hterms=Montreal+protocol&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3D%2528Montreal%2Bprotocol%2529"><span id="translatedtitle"><span class="hlt">Stratospheric</span> Cooling and Arctic Ozone Recovery</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Danilin, Michael Y.; Sze, Nien-Dak; Ko, Malcolm K. W.; Rodriquez, Jose M.</p> <p>1998-01-01</p> <p>We present sensitivity studies using the AER( box model for an idealized parcel in the lower <span class="hlt">stratosphere</span> at 70 N during winter/spring with different assumed <span class="hlt">stratospheric</span> coolings and chlorine loadings. Our calculations show that <span class="hlt">stratospheric</span> cooling could further deplete ozone via increased polar <span class="hlt">stratospheric</span> cloud (PSC) formation and retard its expected recovery even with the projected chlorine loading decrease. We introduce the concept of chlorine-cooling equivalent and show that a 1 K cooling could provide the same local ozone depletion as an increase of chlorine by 0.4-0.7 ppbv for the scenarios considered. Thus, sustained <span class="hlt">stratospheric</span> cooling could further reduce Arctic ozone content and delay the anticipated ozone recovery in the Northern Hemisphere even with the realization of the Montreal Protocol and its Amendments.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19990039174&hterms=Montreal+protocol&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3D%2528Montreal%2Bprotocol%2529','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19990039174&hterms=Montreal+protocol&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3D%2528Montreal%2Bprotocol%2529"><span id="translatedtitle"><span class="hlt">Stratospheric</span> Cooling and Arctic Ozone Recovery</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Danilin, Michael Y.; Sze, Nien-Dak; Ko, Malcolm K. W.; Rodriquez, Jose M.</p> <p>1998-01-01</p> <p>We present sensitivity studies using the AER box model for an idealized parcel in the lower <span class="hlt">stratosphere</span> at 70 deg N during winter/spring with different assumed <span class="hlt">stratospheric</span> cooling and chlorine loadings. Our calculations show that <span class="hlt">stratospheric</span> cooling could further deplete ozone via increased polar <span class="hlt">stratospheric</span> cloud (PSC) formation and retard its expected recovery even with the projected chlorine loading decrease. We introduce the concept of chlorine-cooling equivalent and show that a 1 K Cooling could provide the same local ozone depletion as an increase of chlorine by 0.4-0.7 ppbv for the scenarios considered. Thus, sustained <span class="hlt">stratospheric</span> cooling could further reduce Arctic ozone content and delay the anticipated ozone recovery in the Northern Hemisphere even with the realization of the Montreal Protocol and its Amendments.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20020015683&hterms=Franco&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAuthor-Name%26N%3D0%26No%3D60%26Ntt%3DFranco','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20020015683&hterms=Franco&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAuthor-Name%26N%3D0%26No%3D60%26Ntt%3DFranco"><span id="translatedtitle">What Controls the Arctic Lower <span class="hlt">Stratosphere</span> Temperature?</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Newman, Paul A.; Nash, Eric R.; Einaudi, Franco (Technical Monitor)</p> <p>2001-01-01</p> <p>The temperature of the Arctic lower <span class="hlt">stratosphere</span> is critical for understanding polar ozone levels. As temperatures drop below about 195 K, polar <span class="hlt">stratospheric</span> clouds form, which then convert HCl and ClONO2 into reactive forms that are catalysts for ozone loss reactions. Hence, the lower <span class="hlt">stratospheric</span> temperature during the March period is a key parameter for understanding polar ozone losses. The temperature is basically understood to be a result of planetary waves which drive the polar temperature away from a cold "radiative equilibrium" state. This is demonstrated using NCEP/NCAR reanalysis calculations of the heat flux and the mean polar temperature. The temperature during the March period is fundamentally driven by the integrated impact of large scale waves moving from the troposphere to the <span class="hlt">stratosphere</span> during the January through February period. We will further show that the recent cold years in the northern polar vortex are a result of this weakened wave driving of the <span class="hlt">stratosphere</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20020015679&hterms=Franco&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAuthor-Name%26N%3D0%26No%3D60%26Ntt%3DFranco','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20020015679&hterms=Franco&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAuthor-Name%26N%3D0%26No%3D60%26Ntt%3DFranco"><span id="translatedtitle">The Evolution of <span class="hlt">Stratospheric</span> Data Assimilation Systems</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Rood, Richard B.; Einaudi, Franco (Technical Monitor)</p> <p>2001-01-01</p> <p>The use of model-assimilated meteorological observations for <span class="hlt">stratospheric</span> research has become routine since the late 1980's. The first <span class="hlt">stratospheric</span> assimilation systems were straightforward extensions of systems developed for tropospheric weather forecasting. During the 1990's systems were developed that more directly addressed the specifics of <span class="hlt">stratospheric</span> applications. These developments include better treatment of the satellite observations and improved models that better represent the residual circulation in the assimilated data sets. This talk will review the evolution of <span class="hlt">stratospheric</span> data assimilation and its application, especially to problems of tracer transport. The new data assimilation currently under validation at NASA will be described in some detail, and results from the validation exercise will be presented. This data assimilation system sits at the foundation of a proposed <span class="hlt">stratospheric</span> reanalysis that covers the era of the Upper Atmosphere Research Satellite (UARS).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015GeoRL..42.6852S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015GeoRL..42.6852S"><span id="translatedtitle">Injection of iodine to the <span class="hlt">stratosphere</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Saiz-Lopez, A.; Baidar, S.; Cuevas, C. A.; Koenig, T. K.; Fernandez, R. P.; Dix, B.; Kinnison, D. E.; Lamarque, J.-F.; Rodriguez-Lloveras, X.; Campos, T. L.; Volkamer, R.</p> <p>2015-08-01</p> <p>We report a new estimation of the injection of iodine into the <span class="hlt">stratosphere</span> based on novel daytime (solar zenith angle < 45°) aircraft observations in the tropical tropopause layer and a global atmospheric model with the most recent knowledge about iodine photochemistry. The results indicate that significant levels of total reactive iodine (0.25-0.7 parts per trillion by volume), between 2 and 5 times larger than the accepted upper limits, can be injected into the <span class="hlt">stratosphere</span> via tropical convective outflow. At these iodine levels, modeled iodine catalytic cycles account for up to 30% of the contemporary ozone loss in the tropical lower <span class="hlt">stratosphere</span> and can exert a <span class="hlt">stratospheric</span> ozone depletion potential equivalent to, or even larger than, that of very short-lived bromocarbons. Therefore, we suggest that iodine sources and chemistry need to be considered in assessments of the historical and future evolution of the <span class="hlt">stratospheric</span> ozone layer.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19990063764&hterms=coagulation&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3Dcoagulation','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19990063764&hterms=coagulation&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3Dcoagulation"><span id="translatedtitle">The Life Cycle of <span class="hlt">Stratospheric</span> Aerosol Particles</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Hamill, Patrick; Jensen, Eric J.; Russell, P. B.; Bauman, Jill J.</p> <p>1997-01-01</p> <p>This paper describes the life cycle of the background (nonvolcanic) <span class="hlt">stratospheric</span> sulfate aerosol. The authors assume the particles are formed by homogeneous nucleation near the tropical tropopause and are carried aloft into the <span class="hlt">stratosphere</span>. The particles remain in the Tropics for most of their life, and during this period of time a size distribution is developed by a combination of coagulation, growth by heteromolecular condensation, and mixing with air parcels containing preexisting sulfate particles. The aerosol eventually migrates to higher latitudes and descends across isentropic surfaces to the lower <span class="hlt">stratosphere</span>. The aerosol is removed from the <span class="hlt">stratosphere</span> primarily at mid- and high latitudes through various processes, mainly by isentropic transport across the tropopause from the <span class="hlt">stratosphere</span> into the troposphere.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19990025891','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19990025891"><span id="translatedtitle">Heterogeneous Chemistry Related to <span class="hlt">Stratospheric</span> Aircraft</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Tolbert, Margaret A.</p> <p>1995-01-01</p> <p>Emissions from <span class="hlt">stratospheric</span> aircraft that may directly or indirectly affect ozone include NO(y), H2O, soot and sulfuric acid. To fully assess the impact of such emissions, it is necessary to have a full understanding of both the homogeneous and heterogeneous transformations that may occur in the <span class="hlt">stratosphere</span>. Heterogeneous reactions on <span class="hlt">stratospheric</span> particles play a key role in partitioning ozone-destroying species between their active and reservoir forms. In particular, heterogeneous reactions tend to activate odd chlorine while deactivating odd nitrogen. Accurate modeling of the net atmospheric effects of <span class="hlt">stratospheric</span> aircraft requires a thorough understanding of the competing effects of this activation/deactivation. In addition, a full understanding of the potential aircraft impacts requires that the abundance, composition and formation mechanisms of the particles themselves be established. Over the last three years with support from the High Speed Research Program, we have performed laboratory experiments to determine the chemical composition, formation mechanism, and reactivity of <span class="hlt">stratospheric</span> aerosols.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19910071867&hterms=freezing+point&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dfreezing%2Bpoint','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19910071867&hterms=freezing+point&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dfreezing%2Bpoint"><span id="translatedtitle">Homogeneous freezing nucleation of <span class="hlt">stratospheric</span> solution droplets</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Jensen, Eric J.; Toon, Owen B.; Hamill, Patrick</p> <p>1991-01-01</p> <p>The classical theory of homogeneous nucleation was used to calculate the freezing rate of sulfuric acid solution aerosols under <span class="hlt">stratospheric</span> conditions. The freezing of <span class="hlt">stratospheric</span> aerosols would be important for the nucleation of nitric acid trihydrate particles in the Arctic and Antarctic <span class="hlt">stratospheres</span>. In addition, the rate of heterogeneous chemical reactions on <span class="hlt">stratospheric</span> aerosols may be very sensitive to their state. The calculations indicate that homogeneous freezing nucleation of pure water ice in the <span class="hlt">stratospheric</span> solution droplets would occur at temperatures below about 192 K. However, the physical properties of H2SO4 solution at such low temperatures are not well known, and it is possible that sulfuric acid aerosols will freeze out at temperatures ranging from about 180 to 195 K. It is also shown that the temperature at which the aerosols freeze is nearly independent of their size.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013EPSC....8..343C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013EPSC....8..343C"><span id="translatedtitle">Chemical composition and temperature structure of Titan's <span class="hlt">stratosphere</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Coustenis, A.; Bampasidis, G.; Achterberg, R.; Lavvas, P.; Vinatier, S.; Nixon, C.; Jennings, D.; Teanby, N.; Flasar, F. M.; Orton, G.; Romani, P.; Carlson, R.; Guandique, E. A.</p> <p>2013-09-01</p> <p>We have explored the thermal and chemical composition of Titan's atmosphere by combining Cassini CIRS recordings and the related ground - and space - based observations. The fulfillment of one Titanian year of space observations provides us for the first time with the opportunity to evaluate the relative role of different physical processes in the long term evolution of this complex environment. We find indication for a weakening of the temperature gradient with <span class="hlt">warming</span> of the <span class="hlt">stratosphere</span> and cooling of the lower mesosphere. In addition, we infer precise concentrations for the trace gases and their main isotopologues and find that the chemical composition in Titan's <span class="hlt">stratosphere</span> varies significantly with latitude during the 6 years investigated here, with increased mixing ratios towards the northern latitudes. In particular, we monitor and quantify the amplitu de of a maximum enhancement of several gases observed at northern latitudes up to 50°N around mid-2009, at the time of the NSE. We find that this raise is followed by a rapid decrease in chemical inventory in 2010 probably due to a weakening north polar vortex with reduced lateral mixing across the vortex boundary. By comparing the Cassini/CIRS results from both the limb and the nadir observations with past V1 (1980) and ISO (1997)inferences we find indication for seasonal variations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19910016145','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19910016145"><span id="translatedtitle">The Cl-36 in the <span class="hlt">stratosphere</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Deck, Bruce; Wahlen, Martin; Weyer, Harley; Kubik, Peter; Sharma, Pankaj; Gove, Harry</p> <p>1991-01-01</p> <p>Initial measurements of the cosmogenic radionuclide, Cl-36, in the lower <span class="hlt">stratosphere</span> were made by accelerator mass spectrometry. Samples were obtained using the large volume LASL air sampling pods on a NASA WB-57F aircraft. Untreated (for collection of particulates only) and tetrabutyl ammonium hydroxide treated (for collection of particulates and HCl) IPC-1478 filters were flown on three flights in the lower <span class="hlt">stratosphere</span>. Chlorine (Cl) and Cl compounds are important trace constituents for <span class="hlt">stratospheric</span> chemistry, in particular with respect to O3 destruction. <span class="hlt">Stratospheric</span> Cl chemistry has recently received increased attention with the observation of strong O3 depletion in the Antarctic winter vortex and in the weaker and more complex Arctic winter vortices. Cosmogenic (Cl-36) is produced by spallation reactions from Ar mainly in the <span class="hlt">stratosphere</span>, and has had several applications as a geochemical tracer. The large amounts of Cl-36 introduced by nuclear weapon testing have been removed from the <span class="hlt">stratosphere</span> by now, and measurements in the <span class="hlt">stratosphere</span> to obtain cosmogenic production rates and concentration distributions is now possible. The use of cosmogenic Cl-36 as a tracer for <span class="hlt">stratospheric</span> Cl chemistry and for <span class="hlt">stratospheric</span>/tropospheric exchange processes is investigated. A first attempt to determine <span class="hlt">stratospheric</span> and tropospheric production rates, the partitioning of Cl-36 among particulate and gaseous Cl compounds, and the respective inventories and removal rates is being made. Results from a flight at 13.7 km, 30-33 degrees N, 97-107 degrees W, and from a second flight at 17.7 km, 43-45-36 degrees N, 92-94 degrees W, for the untreated and treated filters respectively are presented.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010AGUFMSA31B1737L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010AGUFMSA31B1737L"><span id="translatedtitle">Is the <span class="hlt">Stratospheric</span> QBO affected by Solar Wind Dynamic Pressure via an Annual Cycle Modulation?</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lu, H.; Jarvis, M. J.</p> <p>2010-12-01</p> <p>This study explores possible solar wind dynamic pressure effects on equatorial temperature and wind with an emphasis on the <span class="hlt">stratospheric</span> Quasi-biennial Oscillation (QBO). The QBO phase occurrence and transition are closely linked to an annual cycle of tropical lower <span class="hlt">stratospheric</span> temperature. The statistical response of the tropical temperature to solar wind dynamic pressure is characterized by ~1.25 K <span class="hlt">warming</span> near the tropopause during the Boreal winter and spring and ~ 0.5 K cooling in the troposphere during the Austral winter and spring. The combined effect of this is a reduction of the amplitude of the annual cycle in temperature in the tropical tropopause region. The weakening of the annual cycle causes systematic and significant change in the tropical upwelling and therefore the strength and phase distribution of the QBO in the lower <span class="hlt">stratosphere</span>. In the lower <span class="hlt">stratosphere</span>, significantly stronger and more frequency easterly anomalies are found to be associated with high solar wind dynamic pressure during August to October. In addition to the seasonal response, there is a small but seasonally invariant response that is characterized by a vertical three-cell anomaly pattern with westerly anomalies in the troposphere and at 3-10 hPa and easterly anomalies in the lower <span class="hlt">stratosphere</span>. We propose that significantly stronger easterly anomalies in the tropical lower <span class="hlt">stratosphere</span> under high solar wind dynamic pressure during the Austral winter and spring are a consequence both of the initializing effect of this three-cell structure and of an amplification effect due to the seasonal modulation of the annual cycle.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19820049127&hterms=pollution+Marina&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dpollution%2BMarina','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19820049127&hterms=pollution+Marina&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dpollution%2BMarina"><span id="translatedtitle"><span class="hlt">Stratospheric</span> aerosols - Observation and theory</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Turco, R. P.; Whitten, R. C.; Toon, O. B.</p> <p>1982-01-01</p> <p>Important chemical and physical roles of aerosols are discussed, and properties of <span class="hlt">stratospheric</span> aerosols as revealed by experimental data are described. In situ measurements obtained by mechanical collection and scattered-light detection yield the overall size distribution of the aerosols, and analyses of preserved aerosol precursor gases by wet chemical, cryogenic and spectroscopic techniques indicate the photochemical sources of particle mass. Aerosol chemical reactions including those of gaseous precursors, those in aqueous solution, and those on particle surfaces are discussed, in addition to aerosol microphysical processes such as nucleation, condensation/evaporation, coagulation and sedimentation. Models of aerosols incorporating such chemical and physical processes are presented, and simulations are shown to agree with measurements. Estimates are presented for the potential aerosol changes due to emission of particles and gases by aerospace operations and industrial consumption of fossil fuels, and it is demonstrated that although the climatic effects of existing levels of <span class="hlt">stratospheric</span> aerosol pollution are negligible, potential increases in those levels might pose a future threat.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1995GeoRL..22.1725T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1995GeoRL..22.1725T"><span id="translatedtitle">Freezing behavior of <span class="hlt">stratospheric</span> sulfate aerosols inferred from trajectory studies</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tabazadeh, A.; Toon, O. B.; Hamill, Patrick</p> <p></p> <p>Temperature histories based on 10-day back trajectories for six ER-2 flights during AASE I (1989) and AAOE (1987) are presented. These trajectories along with the properties of the observed PSC (polar <span class="hlt">stratospheric</span> cloud) particles are used here to infer the physical state of the preexisting sulfuric acid aerosols. Of all the ER-2 flights described here, only the PSCs observed on the flights of January 24 and 25, 1989 are consistent with the thermo-dynamics of liquid ternary solutions of H2SO4/HNO3/H2O (Type Ib PSCs). For these two days, back trajectories indicate that the air mass was exposed to SAT (sulfuric acid tetrahydrate) melting temperatures about 24 hours prior to being sampled by the ER-2. For the remaining ER-2 flights (January, 16, 19, and 20 for the AASE I campaign and August 17 for the AAOE campaign), the observed PSCs were probably composed of amorphous solid solutions of HNO3 and H2O (Type Ic PSCs). Formation of such Type Ic PSCs requires the presence of solid H2SO4 aerosols since liquid aerosols yield ternary solutions. The 10-day back trajectories of these flights indicate that the air mass was not exposed to SAT melting temperatures during the past week and had experienced cooling/<span class="hlt">warming</span> cycles prior to being sampled by the ER-2. These temperature histories, recent laboratory measurements and the properties of glassy solids suggest that <span class="hlt">stratospheric</span> H2SO4 aerosols may undergo a phase transition to SAT upon <span class="hlt">warming</span> at ∼ 198 K after going through a cooling cycle to about 194 K or lower.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007ACPD....7.8933P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007ACPD....7.8933P"><span id="translatedtitle">Is there a <span class="hlt">stratospheric</span> fountain?</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Pommereau, J.-P.; Held, G.</p> <p>2007-06-01</p> <p>The impact of convection on the thermal structure of the Tropical Tropopause Layer (TTL) was investigated from a series of four daily radiosonde ascents and weather S-band radar observations carried out during the HIBISCUS campaign in the South Atlantic Convergence Zone in Southeast Brazil in February 2004. The temperature profiles display a large impact of convective activity on the thermal structure of the TTL. Compared to non-active periods, convection is observed to result in a cooling of 4.5°C to 7.5°C at the Lapse Rate Tropopause at 16 km, propagating up to 19 km or 440 K potential temperature levels in the <span class="hlt">stratosphere</span> in most intense convective cases. Consistent with the diurnal cycle of echo top heights seen by a S-band weather radar, a systematic temperature diurnal cycle is observed in the layer, displaying a rapid cooling of 3.5°C on average (-9°, -2°C extremes) during the development phase of convection in the early afternoon during the most active period. Since the cooling occurs during daytime within a timescale of 6-h, its maximum amplitude is at the altitude of the Cold Point Tropopause at 390 K and temperature fluctuations associated to gravity waves do not display significant diurnal change, the afternoon cooling of the TTL cannot be attributed to radiation, advection, gravity waves or adiabatic lofting. It implies a fast insertion of adiabatically cooled air parcels by overshooting turrets followed by mixing with the warmer environment. During most intense convective days, the overshoot is shown to penetrate the <span class="hlt">stratosphere</span> up to 450 K potential temperature level. Such fast updraft offers an explanation for the presence of ice crystals, and enhanced water vapour layers observed up to 18-19 km (410-430 K) in the same area by the HIBISCUS balloons and the TROCCINOX Geophysica aircraft, as well as high tropospheric chemical species concentrations in the TTL over land observed from space. Overall, injection of cold air by irreversible mixing</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19850044892&hterms=LIMS&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3DLIMS','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19850044892&hterms=LIMS&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3DLIMS"><span id="translatedtitle">The global distribution and variability of <span class="hlt">stratospheric</span> constituents measured by LIMS. [Limb Infrared Monitor of the <span class="hlt">Stratosphere</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Russell, J. M., III</p> <p>1984-01-01</p> <p>The purpose of the Nimbus 7 LIMS experiment was to sound the composition and structure of the upper atmosphere and provide data for study of photochemistry, radiation, and dynamics processes. Vertical profiles were measured of temperature and ozone (O3) over the 10-km to 65-km range and water vapor, nitrogen dioxide, and nitric acid over the 10-km to 50-km range. Latitude coverage extended from 64 deg S to 84 deg N. Several general features of the atmosphere have emerged from data analyzes thus far. Nitrogen dioxide exhibits rapid latitudinal variations in winter and shows hemispheric asymmetry with generally higher vertical column amount in the summer hemisphere. HNO3 data show that this gas is highly variable with altitude, latitude, and season. Smallest mixing ratios occur in the tropics, and the largest values occur in the high latitude winter hemisphere. The results show that O3, NO2, and HNO3 are strongly affected during a <span class="hlt">stratospheric</span> <span class="hlt">warming</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010AGUFM.A33A0141X','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010AGUFM.A33A0141X"><span id="translatedtitle">Ozone recovery may enhance global <span class="hlt">warming</span> in the 21st century</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Xia, Y.; Hu, Y.</p> <p>2010-12-01</p> <p>Observations show a stabilization or weak increasing of the <span class="hlt">stratospheric</span> ozone layer since the late 1990s. Recent coupled chemistry-climate model simulations predicted that the <span class="hlt">stratospheric</span> ozone layer will likely return to pre-1980 levels in the middle of the 21st century, as a result of the decline of ozone depleting substances under the 1987 Montreal Protocol. Since the ozone layer is an important component in determining <span class="hlt">stratospheric</span> and tropospheric-surface energy balance, the recovery of the ozone layer may have significant impact on tropospheric-surface climate. Here, using multi-model ensemble results from both the Intergovernmental Panel on Climate Change Fourth Assessment Report (IPCC-AR4) models and coupled chemistry-climate models, we show that as ozone recovery is considered, the troposphere is <span class="hlt">warmed</span> more than that without considering ozone recovery, suggesting an enhancement of tropospheric <span class="hlt">warming</span> due to ozone recovery. It is found that the enhanced tropospheric <span class="hlt">warming</span> is mostly significant in the upper troposphere, with global mean magnitudes of about 0.41 K for A1B scenario and about 0.2 K for A2 and B1 scenarios over the period of 2001-2050. We also find that relatively large enhanced <span class="hlt">warming</span> occurs in the extratratropics and polar regions in summer and autumn in both hemispheres while the enhanced <span class="hlt">warming</span> is stronger in the Northern Hemisphere than in the Southern Hemisphere. Enhanced <span class="hlt">warming</span> is also found at the surface. The strongest enhancement of surface <span class="hlt">warming</span> is located in the Arctic in boreal winter. The global annual mean enhancement of surface <span class="hlt">warming</span> is about 0.16 K, 0.08 K and 0.13 K for A1B, A2, and B1 over 2001-2050, respectively.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://eric.ed.gov/?q=Warm+AND+Up&pg=5&id=EJ601591','ERIC'); return false;" href="http://eric.ed.gov/?q=Warm+AND+Up&pg=5&id=EJ601591"><span id="translatedtitle"><span class="hlt">Warm</span>-Up Activities.</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Mingguang, Yang</p> <p>1999-01-01</p> <p>Discusses how <span class="hlt">warm</span>-up activities can help to make the English-as-a-foreign-language classroom a lively and interesting place. <span class="hlt">Warm</span>-up activities are games carried out at the beginning of each class to motivate students to make good use of class time. (Author/VWL)</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22086224','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22086224"><span id="translatedtitle">THERMAL AND CHEMICAL STRUCTURE VARIATIONS IN TITAN'S <span class="hlt">STRATOSPHERE</span> DURING THE CASSINI MISSION</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Bampasidis, Georgios; Coustenis, A.; Vinatier, S.; Achterberg, R. K.; Lavvas, P.; Nixon, C. A.; Jennings, D. E.; Flasar, F. M.; Carlson, R. C.; Romani, P. N.; Guandique, E. A.; Teanby, N. A.; Moussas, X.; Preka-Papadema, P.; Stamogiorgos, S.</p> <p>2012-12-01</p> <p>We have developed a line-by-line Atmospheric Radiative Transfer for Titan code that includes the most recent laboratory spectroscopic data and haze descriptions relative to Titan's <span class="hlt">stratosphere</span>. We use this code to model Cassini Composite Infrared Spectrometer data taken during the numerous Titan flybys from 2006 to 2012 at surface-intercepting geometry in the 600-1500 cm{sup -1} range for latitudes from 50 Degree-Sign S to 50 Degree-Sign N. We report variations in temperature and chemical composition in the <span class="hlt">stratosphere</span> during the Cassini mission, before and after the Northern Spring Equinox (NSE). We find indication for a weakening of the temperature gradient with <span class="hlt">warming</span> of the <span class="hlt">stratosphere</span> and cooling of the lower mesosphere. In addition, we infer precise concentrations for the trace gases and their main isotopologues and find that the chemical composition in Titan's <span class="hlt">stratosphere</span> varies significantly with latitude during the 6 years investigated here, with increased mixing ratios toward the northern latitudes. In particular, we monitor and quantify the amplitude of a maximum enhancement of several gases observed at northern latitudes up to 50 Degree-Sign N around mid-2009, at the time of the NSE. We find that this rise is followed by a rapid decrease in chemical inventory in 2010 probably due to a weakening north polar vortex with reduced lateral mixing across the vortex boundary.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AGUFM.A11J0190I','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AGUFM.A11J0190I"><span id="translatedtitle">Gravitational Separation in the <span class="hlt">Stratosphere</span> - A New Tracer of Atmospheric Circulation</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ishidoya, S.; Sugawara, S.; Morimoto, S.; Aoki, S.; Nakazawa, T.; Honda, H.; Murayama, S.</p> <p>2012-12-01</p> <p>As a basic knowledge of atmospheric science, it has been believed that the gravitational separation of atmospheric components is observable only in the atmosphere above the turbopause. Despite this common perception, we found, from high-precision measurements not only of the isotopic ratios of N2, O2 and Ar but also of the concentration of Ar, that the gravitational separation occurs significantly even in the <span class="hlt">stratosphere</span>; their observed vertical profiles are in good agreement with those expected theoretically from molecular mass differences. The O2/N2 ratio observed in the middle <span class="hlt">stratosphere</span>, corrected for the gravitational separation, showed the same mean air age as estimated from the CO2 concentration. Simulations with a 2-dimensional NCAR model (SOCRATES) also indicated that a relationship between the gravitational separation and the air age in the <span class="hlt">stratosphere</span> would be affected by an enhancement of the Brewer-Dobson circulation due to global <span class="hlt">warming</span>. Therefore, the gravitational separation would be usable as a new tracer for an understanding of atmospheric circulation in the <span class="hlt">stratosphere</span>.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li class="active"><span>17</span></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_17 --> <div id="page_18" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li class="active"><span>18</span></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="341"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AGUFMGC51A1156O','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AGUFMGC51A1156O"><span id="translatedtitle">Simulation of the climate effects of a geoengineered <span class="hlt">stratospheric</span> sulfate cloud with the NASA GEOSCCM</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Oman, L.; Aquila, V.; Colarco, P. R.</p> <p>2012-12-01</p> <p>Suggested solar radiation management (SRM) methods to mitigate global <span class="hlt">warming</span> include the injection of sulfur dioxide (SO2 ) in the <span class="hlt">stratosphere</span>. We present the results from SRM simulation ensemble performed with the NASA GEOS-5 Chemistry Climate Model (GEOSCCM). We focus on the response of the <span class="hlt">stratosphere</span> to a <span class="hlt">stratospheric</span> SO2 injection. In particular, we investigate the changes of the <span class="hlt">stratospheric</span> dynamics and composition, and the impact of an increased aerosol layer on ozone recovery. As prescribed for experiment G4 of the Geoengineering Model Intercomparison Project (GeoMIP), we inject 5 Tg/year of SO2 from 2020 to 2070. The location of the injection is the equator at 0° longitude between 16 km and 25 km altitude. After 2070, we interrupt the SO2 injection and simulate the readjustment until 2090. The emissions scenario is RCP4.5, which predicts a radiative forcing of about 4.5 W/m2 by 2100. This is considered a "medium-low" scenario in terms of radiative forcing. GEOSCCM does not include an interactive ocean model, therefore we use the sea surface temperatures forecasted by the Community Climate System Model Version 4 (CCSM4) for RCP4.5.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016EGUGA..1817204M&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016EGUGA..1817204M&link_type=ABSTRACT"><span id="translatedtitle">The ISA-MIP Historical Eruption SO2 Emissions Assessment (HErSEA): an intercomparison for interactive <span class="hlt">stratospheric</span> aerosol models</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Mann, Graham; Dhomse, Sandip; Sheng, Jianxiong; Mills, Mike</p> <p>2016-04-01</p> <p>Major historical volcanic eruptions have injected huge amounts of sulphur dioxide into the <span class="hlt">stratosphere</span> with observations showing an enhancement of the <span class="hlt">stratospheric</span> aerosol layer for several years (ASAP, 2006). Such long-lasting increases in <span class="hlt">stratospheric</span> aerosol loading cool the Earth's surface by scattering incoming solar radiation and <span class="hlt">warm</span> the <span class="hlt">stratosphere</span> via absorption of near infra-red solar and long-wave terrestrial radiation with complex effects on climate (e.g. Robock, 2000). Two recent modelling studies of Mount Pinatubo (Dhomse et al., 2014; Sheng et al. 2015) have highlighted that observations suggest the sulphur loading of the volcanically enhanced <span class="hlt">stratospheric</span> aerosol may have been considerably lower than suggested by measurements of the injected SO2. This poster describes a new model intercomparison activity "ISA-MIP" for interactive <span class="hlt">stratospheric</span> aerosol models within the framework of the SPARC initiative on <span class="hlt">Stratospheric</span> Sulphur and its Role in Climate (SSiRC). The new "Historical Eruption SO2 emissions Assessment" (HErSEA) will intercompare model simulations of the three largest volcanic perturbations to the <span class="hlt">stratosphere</span> in the last 50 years, 1963 Mt Agung, 1982 El Chichon and 1991 Mt Pinatubo. The aim is to assess how effectively the emitted SO2 translates into perturbations to <span class="hlt">stratospheric</span> aerosol properties and simulated radiative forcings in different composition-climate models with interactive <span class="hlt">stratospheric</span> aerosol (ISA). Each modelling group will run a mini-ensemble of transient AMIP-type runs for the 3 eruptions with a control no-eruption run followed by upper and lower bound injection amount estimates and 3 different injection height settings for two shallow (e.g. 19-21km amd 23-25km) and one deep (e.g. 19-25km) injection. First order analysis will intercompare <span class="hlt">stratospheric</span> aerosol metrics such as 2D-monthly AOD(550nm, 1020nm) and timeseries of tropical and NH/SH mid-visible extinction at three different models levels (15, 20 and 25km</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFM.A23L3423D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFM.A23L3423D"><span id="translatedtitle">Why Does the <span class="hlt">Stratosphere</span> Get Wetter During the 21st Century?</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Dessler, A. E.; Schoeberl, M. R.; Wang, T.; Douglass, A. R.; Oman, L.</p> <p>2014-12-01</p> <p>All chemistry-climate models predict that 1) the TTL <span class="hlt">warms</span> during the 21st century and 2) that the humidity of air entering the <span class="hlt">stratosphere</span> increases over this same period. It seems reasonable to conclude that the former causes the latter, but to our knowledge no one has actually tested that. We do so here by analyzing one chemistry-climate model in detail (the Goddard Earth Observing System Chemistry Climate Model, GEOSCCM) and find that the <span class="hlt">warming</span> of the TTL explains only a fraction of the increase in humidity of air entering the <span class="hlt">stratosphere</span>. We do this by using meteorological fields from the model to drive a trajectory model, which estimates the water vapor variations in response to the large-scale temperature field. Water vapor simulated by the trajectory model increases by about one quarter of the amount it increases in the GEOSCCM. We conclude that, over the 21st century, an increase in the flux of ice through the TTL is responsible for most of the increase in the humidity of air entering the <span class="hlt">stratosphere</span> in this model.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20150000795','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20150000795"><span id="translatedtitle">Why Does the <span class="hlt">Stratosphere</span> Get Moister During the 21st Century?</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Dessler, A.E.; Schoberl, M. R.; Ye, H.; Wang, T.; Oman, L.; Douglass, A. R.</p> <p>2014-01-01</p> <p>All chemistry-climate models predict that 1) the TTL <span class="hlt">warms</span> during the 21st century and 2) that the humidity of air entering the <span class="hlt">stratosphere</span> increases over this same period. It seems reasonable to conclude that the former causes the latter, but to our knowledge no one has actually tested that. We do so here by analyzing one chemistry-climate model in detail (the Goddard Earth Observing System Chemistry Climate Model, GEOSCCM) and find that the <span class="hlt">warming</span> of the TTL explains only a fraction of the increase in humidity of air entering the <span class="hlt">stratosphere</span>. We do this by using meteorological fields from the model to drive a trajectory model, which estimates the water vapor variations in response to the large-scale temperature field. Water vapor simulated by the trajectory model increases by about one quarter of the amount it increases in the GEOSCCM. We conclude that, over the 21st century, an increase in the flux of ice through the TTL is responsible for most of the increase in the humidity of air entering the <span class="hlt">stratosphere</span> in this model.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016ACP....16.4191N&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016ACP....16.4191N&link_type=ABSTRACT"><span id="translatedtitle"><span class="hlt">Stratospheric</span> ozone changes under solar geoengineering: implications for UV exposure and air quality</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Nowack, Peer Johannes; Abraham, Nathan Luke; Braesicke, Peter; Pyle, John Adrian</p> <p>2016-03-01</p> <p>Various forms of geoengineering have been proposed to counter anthropogenic climate change. Methods which aim to modify the Earth's energy balance by reducing insolation are often subsumed under the term solar radiation management (SRM). Here, we present results of a standard SRM modelling experiment in which the incoming solar irradiance is reduced to offset the global mean <span class="hlt">warming</span> induced by a quadrupling of atmospheric carbon dioxide. For the first time in an atmosphere-ocean coupled climate model, we include atmospheric composition feedbacks for this experiment. While the SRM scheme considered here could offset greenhouse gas induced global mean surface <span class="hlt">warming</span>, it leads to important changes in atmospheric composition. We find large <span class="hlt">stratospheric</span> ozone increases that induce significant reductions in surface UV-B irradiance, which would have implications for vitamin D production. In addition, the higher <span class="hlt">stratospheric</span> ozone levels lead to decreased ozone photolysis in the troposphere. In combination with lower atmospheric specific humidity under SRM, this results in overall surface ozone concentration increases in the idealized G1 experiment. Both UV-B and surface ozone changes are important for human health. We therefore highlight that both <span class="hlt">stratospheric</span> and tropospheric ozone changes must be considered in the assessment of any SRM scheme, due to their important roles in regulating UV exposure and air quality.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20040082134','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20040082134"><span id="translatedtitle">Extratropical <span class="hlt">Stratosphere</span>-Troposphere Mass Exchange</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Schoeberl, Mark R.</p> <p>2004-01-01</p> <p>Understanding the exchange of gases between the <span class="hlt">stratosphere</span> and the troposphere is important for determining how pollutants enter the <span class="hlt">stratosphere</span> and how they leave. This study does a global analysis of that the exchange of mass between the <span class="hlt">stratosphere</span> and the troposphere. While the exchange of mass is not the same as the exchange of constituents, you can t get the constituent exchange right if you have the mass exchange wrong. Thus this kind of calculation is an important test for models which also compute trace gas transport. In this study I computed the mass exchange for two assimilated data sets and a GCM. The models all agree that amount of mass descending from the <span class="hlt">stratosphere</span> to the troposphere in the Northern Hemisphere extra tropics is approx. 10(exp 10) kg/s averaged over a year. The value for the Southern Hemisphere by about a factor of two. ( 10(exp 10) kg of air is the amount of air in 100 km x 100 km area with a depth of 100 m - roughly the size of the D.C. metro area to a depth of 300 feet.) Most people have the idea that most of the mass enters the <span class="hlt">stratosphere</span> through the tropics. But this study shows that almost 5 times more mass enters the <span class="hlt">stratosphere</span> through the extra-tropics. This mass, however, is quickly recycled out again. Thus the lower most <span class="hlt">stratosphere</span> is a mixture of upper <span class="hlt">stratospheric</span> air and tropospheric air. This is an important result for understanding the chemistry of the lower <span class="hlt">stratosphere</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19980015254','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19980015254"><span id="translatedtitle">Laboratory Investigations of <span class="hlt">Stratospheric</span> Halogen Chemistry</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Wine, Paul H.; Nicovich, J. Michael; Stickel, Robert E.; Hynes, Anthony J.</p> <p>1997-01-01</p> <p>A final report for the NASA-supported project on laboratory investigations of <span class="hlt">stratospheric</span> halogen chemistry is presented. In recent years, this project has focused on three areas of research: (1) kinetic, mechanistic, and thermochemical studies of reactions which produce weakly bound chemical species of atmospheric interest; (2) development of flash photolysis schemes for studying radical-radical reactions of <span class="hlt">stratospheric</span> interest; and (3) photochemistry studies of interest for understanding <span class="hlt">stratospheric</span> chemistry. The first section of this paper contains a discussion of work which has not yet been published. All subsequent chapters contain reprints of published papers that acknowledge support from this grant.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/150489','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/150489"><span id="translatedtitle">Observed <span class="hlt">stratospheric</span> profiles and <span class="hlt">stratospheric</span> lifetimes of HCFC-141b and HCFC-142b</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Lee, J.M.; Sturges, W.T.; Penkett, S.A.</p> <p>1995-06-01</p> <p>The authors present profile measurements of HCFC-141b and HCFC-142b in the <span class="hlt">stratosphere</span>. The measurements show that these chemicals are not in equilibrium in the <span class="hlt">stratosphere</span> at present, and allow inferences of <span class="hlt">stratospheric</span> lifetimes. The lifetimes are strongly dependent upon the actual N{sub 2}O lifetime, and for an N{sub 2}O lifetime of 110y, are 68 {+-} 11y for HCFC-141b and a minimum of 138y for HCFC-142b.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19990077343&hterms=tide&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Dtide','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19990077343&hterms=tide&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Dtide"><span id="translatedtitle"><span class="hlt">Stratospheric</span> Tides and Data Assimilation</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Swinbank, R.; Orris, R. L.; Wu, D. L.</p> <p>1999-01-01</p> <p>In the upper <span class="hlt">stratosphere</span>, the atmosphere exhibits significant diurnal and semi-diurnal tidal variations, with typical amplitude of about 2K in mid-latitudes. In this paper we examine how well the tidal variations in temperature are represented by the Goddard Geodesic Earth Orbiting Satellite (GEOS-2) data assimilation system. We show that the GEOS-2 atmospheric model is quite successful at simulating the tidal temperature variations. However, the assimilation of satellite temperature soundings significantly damps the simulated tides. The reason is because the tides are not well represented by the satellite retrievals used by the assimilation system (which have a typical tidal amplitude of around 1K). As a result of this study, we suggest improvements that should be made to the treatment of satellite soundings by the assimilation system.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19890056696&hterms=denitrification&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Ddenitrification','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19890056696&hterms=denitrification&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Ddenitrification"><span id="translatedtitle">Denitrification in the Antarctic <span class="hlt">stratosphere</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Salawitch, R. J.; Gobbi, G. P.; Wofsy, S. C.; Mcelroy, M. B.</p> <p>1989-01-01</p> <p>Rapid loss of ozone over Antarctica in spring requires that the abundance of gaseous nitric acid be very low. Precipitation of particulate nitric acid has been assumed to occur in association with large ice crystals, requiring significant removal of H2O and temperatures well below the frost point. However, <span class="hlt">stratospheric</span> clouds exhibit a bimodal size distribution in the Antarctic atmosphere, with most of the nitrate concentrated in particles with radii of 1 micron or greater. It is argued here that the bimodal size distribution sets the stage for efficient denitrification, with nitrate particles either falling on their own or serving as nuclei for the condensation of ice. Denitrification can therefore occur without significant dehydration, and it is unnecessary for temperatures to drop significantly below the frost point.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19870050668&hterms=Hydrogen+peroxide&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3D%2528Hydrogen%2Bperoxide%2529','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19870050668&hterms=Hydrogen+peroxide&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3D%2528Hydrogen%2Bperoxide%2529"><span id="translatedtitle">Evidence for <span class="hlt">stratospheric</span> hydrogen peroxide</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Chance, K. V.; Traub, W. A.</p> <p>1987-01-01</p> <p>A statistically significant measurement of H2O2 in the <span class="hlt">stratosphere</span> has been obtained. The results were obtained from the 112.19/cm RQ5 branch of the torsional-rotational spectrum with a remote-sensing far-infrared Fourier transform spectrometer during the Balloon Intercomparison Campaign (BIC-2), on June 20, 1983. The concentration above the balloon gondola is unexpectedly large, corresponding to 0.68 + or - 0.21 parts per billion by volume (ppbv) at an effective altitude of 38.3 km. Below the gondola altitude the concentration of H2O2 is slightly less than expected from the model predictions at 33.2 km (0.19 + or - 0.05 ppbv) and significantly less than expected at 29.3 km (0.08 + or - 0.03 ppbv).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFM.A23J3385R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFM.A23J3385R"><span id="translatedtitle">Pronounced Minima in Tropospheric Ozone and OH above the Tropical West Pacific and their Role for <span class="hlt">Stratospheric</span> Composition</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Rex, M.; Wohltmann, I.; Lehmann, R.; Rosenlof, K. H.; Wennberg, P. O.; Weisenstein, D. K.; Notholt, J.; Krüger, K.; Mohr, V.; Tegtmeier, S.</p> <p>2014-12-01</p> <p>Hundreds of organic species are emitted into the atmosphere mostly from biogenic processes. The rapid breakdown by reactions with OH radicals prevents most of them from reaching the <span class="hlt">stratosphere</span>. Hence, the omnipresent layer of OH in the troposphere shields the <span class="hlt">stratosphere</span> from these emissions and is particularly relevant for those species that do not photolyse efficiently. Reactions involving ozone are a strong source of OH in clean tropical air. Hence the OH concentration is closely coupled to ozone abundances. The Western Pacific <span class="hlt">warm</span> pool is key for troposphere to <span class="hlt">stratosphere</span> exchange. We report measurements of 14 ozonesondes launched during the Transbrom ship cruise through the center of the <span class="hlt">warm</span> pool. During a 2500km portion of the ship track between 10S and 15N we found ozone concentrations below the detection limit of the sondes throughout the troposphere. We will discuss the uncertainties of ozonesonde measurements at very low ozone concentrations, the robustness of our observations and the upper limit of the ozone concentration that would be consistent with our raw data. Based on modelling and measurements of OH on the ER-2 during the STRAT campaign we suggest that there also is a pronounced minimum in the tropospheric column of OH over the tropical West Pacific. We show that this increases the lifetime of chemical species and has the potential to amplify the impact of surface emissions on the <span class="hlt">stratospheric</span> composition. Specifically, we discuss the role of emissions of biogenic halogenated species from this geographic region for <span class="hlt">stratospheric</span> ozone depletion. Also, we discuss the potential role of increasing anthropogenic emissions of SO2 in South East Asia or from minor volcanic eruptions for the <span class="hlt">stratospheric</span> aerosol budget.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/121739','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/121739"><span id="translatedtitle">Modeling the effects of UV variability and the QBO on the troposphere-<span class="hlt">stratosphere</span> system. Part I: The middle atmosphere</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Balachandran, N.K.; Rind, D.</p> <p>1995-08-01</p> <p>Results of experiments with a GCM involving changes in UV input ({plus_minus}25%, {plus_minus}10%, {plus_minus}5% at wavelengths below 0.3 {mu}m) and simulated equatorial QBO are presented, with emphasis on the middle atmosphere response. The UV forcing employed is larger than observed during the last solar cycle and does not vary with wavelength, hence the relationship of these results to those from actual solar UV forcing should be treated with caution. The QBO alters the location of the zero wind line and the horizontal shear of the zonal wind in the low to middle <span class="hlt">stratosphere</span>, while the UV change alters the magnitude of the polar jet and the vertical shear of the zonal wind. Both mechanisms thus affect planetary wave propagation. The east phase of the QBO leads to tropical cooling and high-latitude <span class="hlt">warming</span> in the lower <span class="hlt">stratosphere</span>, with opposite effects in the upper <span class="hlt">stratosphere</span>. This quadrupole pattern is also seen in the observations. The high-latitude responses are due to altered planetary wave effects, while the model`s tropical response in the upper <span class="hlt">stratosphere</span> is due to gravity wave drag. Increased UV forcing <span class="hlt">warms</span> tropical latitudes in the middle atmosphere, resulting in stronger extratropical west winds, an effect which peaks in the upper <span class="hlt">stratosphere</span>/lower mesosphere with the more extreme UV forcing but at lower altitudes and smaller wind variations with the more realistic forcing. The increased vertical gradient of the zonal wind leads to increased vertical propagation of planetary waves, altering energy convergences and temperatures. The exact altitudes affected depend upon the UV forcing applied. Results with combined QBO and UV forcing show that in the Northern Hemisphere, polar <span class="hlt">warming</span> for the east QBO is stronger when the UV input is reduced by 25% and 5% as increased wave propagation to high latitudes (east QBO effect) is prevented from then propagating vertically (reduced UV effect). 30 refs., 14 figs., 6 tabs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011ACPD...1132535D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011ACPD...1132535D"><span id="translatedtitle">The 2009-2010 arctic <span class="hlt">stratospheric</span> winter - general evolution, mountain waves and predictability of an operational weather forecast model</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Dörnbrack, A.; Pitts, M. C.; Poole, L. R.; Orsolini, Y. J.; Nishii, K.; Nakamura, H.</p> <p>2011-12-01</p> <p>The relatively <span class="hlt">warm</span> 2009-2010 Arctic winter was an exceptional one as the North Atlantic Oscillation index attained persistent extreme negative values. Here, selected aspects of the Arctic <span class="hlt">stratosphere</span> during this winter inspired by the analysis of the international field experiment RECONCILE are presented. First of all, and as a kind of reference, the evolution of the polar vortex in its different phases is documented. Special emphasis is put on explaining the formation of the exceptionally cold vortex in mid winter after a sequence of <span class="hlt">stratospheric</span> disturbances which were caused by upward propagating planetary waves. A major sudden <span class="hlt">stratospheric</span> <span class="hlt">warming</span> (SSW) occurring near the end of January 2010 concluded the anomalous cold vortex period. Wave ice polar <span class="hlt">stratospheric</span> clouds were frequently observed by spaceborne remote-sensing instruments over the Arctic during the cold period in January 2010. Here, one such case observed over Greenland is analysed in more detail and an attempt is made to correlate flow information of an operational numerical weather prediction model to the magnitude of the mountain-wave induced temperature fluctuations. Finally, it is shown that the forecasts of the ECMWF ensemble prediction system for the onset of the major SSW were very skilful and the ensemble spread was very small. However, the ensemble spread increased dramatically after the major SSW, displaying the strong non-linearity and internal variability involved in the SSW event.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012ACP....12.3659D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012ACP....12.3659D"><span id="translatedtitle">The 2009-2010 Arctic <span class="hlt">stratospheric</span> winter - general evolution, mountain waves and predictability of an operational weather forecast model</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Dörnbrack, A.; Pitts, M. C.; Poole, L. R.; Orsolini, Y. J.; Nishii, K.; Nakamura, H.</p> <p>2012-04-01</p> <p>The relatively <span class="hlt">warm</span> 2009-2010 Arctic winter was an exceptional one as the North Atlantic Oscillation index attained persistent extreme negative values. Here, selected aspects of the Arctic <span class="hlt">stratosphere</span> during this winter inspired by the analysis of the international field experiment RECONCILE are presented. First of all, and as a kind of reference, the evolution of the polar vortex in its different phases is documented. Special emphasis is put on explaining the formation of the exceptionally cold vortex in mid winter after a sequence of <span class="hlt">stratospheric</span> disturbances which were caused by upward propagating planetary waves. A major sudden <span class="hlt">stratospheric</span> <span class="hlt">warming</span> (SSW) occurring near the end of January 2010 concluded the anomalous cold vortex period. Wave ice polar <span class="hlt">stratospheric</span> clouds were frequently observed by spaceborne remote-sensing instruments over the Arctic during the cold period in January 2010. Here, one such case observed over Greenland is analysed in more detail and an attempt is made to correlate flow information of an operational numerical weather prediction model to the magnitude of the mountain-wave induced temperature fluctuations. Finally, it is shown that the forecasts of the ECMWF ensemble prediction system for the onset of the major SSW were very skilful and the ensemble spread was very small. However, the ensemble spread increased dramatically after the major SSW, displaying the strong non-linearity and internal variability involved in the SSW event.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/445371','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/445371"><span id="translatedtitle">The chemistry of <span class="hlt">stratospheric</span> ozone depletion</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Tuck, A.</p> <p>1997-01-01</p> <p>In the early 1980`s the Antarctic ozone hole was discovered. The ozone loss was 50 percent in the lower <span class="hlt">stratosphere</span> during springtime, which is made possible by the conditions over Antarctica in winter. The absence of sunlight in the <span class="hlt">stratosphere</span> during polar winter causes the <span class="hlt">stratospheric</span> air column there to cool and sink, drawing air from lower latitudes into the upper <span class="hlt">stratosphere</span>. This lower-latitude air gets closer to the Earth`s axis of rotation as it moves poleward and is accelerated by the need to conserve angular momentum to greater and greater westerly wind speeds forming a vortex bounded by the polar night jet stream. The air entering the vortex contains reactive ozone-destroying species. The observed ozone losses occurred concurrently with increases of chlorofluorocarbon increases.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19840040381&hterms=doherty&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAuthor-Name%26N%3D0%26No%3D50%26Ntt%3Ddoherty','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19840040381&hterms=doherty&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAuthor-Name%26N%3D0%26No%3D50%26Ntt%3Ddoherty"><span id="translatedtitle">Radiative heating rates near the <span class="hlt">stratospheric</span> fountain</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Doherty, G. M.; Newell, R. E.; Danielsen, E. F.</p> <p>1984-01-01</p> <p>Radiative heating rates are computed for various sets of conditions thought to be appropriate to the <span class="hlt">stratospheric</span> fountain region: with and without a layer of cirrus cloud between 100 and 150 mbar; with standard ozone and with decreased ozone in the lower <span class="hlt">stratosphere</span>, again with and without the cirrus cloud; and with different temperatures in the tropopause region. The presence of the cloud decreases the radiative cooling below the cloud in the upper troposphere and increases the cooling above it in the lower <span class="hlt">stratosphere</span>. The cloud is heated at the base and cooled at the top and thus radiatively destabilized; overall it gains energy by radiation. Decreasing ozone above the cloud also tends to cool the lower <span class="hlt">stratosphere</span>. The net effect is a tendency for vertical convergence and horizontal divergence in the cloud region. High resolution profiles of temperature, ozone, and cloudiness within the fountain region are required in order to assess the final balance of the various processes.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19870036267&hterms=Cloud+Computing&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3DCloud%2BComputing','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19870036267&hterms=Cloud+Computing&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3DCloud%2BComputing"><span id="translatedtitle">Polar <span class="hlt">stratospheric</span> clouds inferred from satellite data</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Austin, J.; Jones, R. L.; Remsberg, E. E.; Tuck, A. F.</p> <p>1986-01-01</p> <p>Anomalously high radiances from the ozone channel of the Limb Infrared Monitor of the <span class="hlt">Stratosphere</span> (LIMS) sounding instrument have been observed in the Northern Hemisphere winter lower <span class="hlt">stratosphere</span>. Such events, thought to be due to polar <span class="hlt">stratospheric</span> clouds (PSCs), are examined further by computing relative humidities using <span class="hlt">Stratospheric</span> Sounding Unit temperatures and water vapor measurements from the LIMS Map Archive Tape analyses. Regions identified as PSCs are found to correspond closely to regions of high humidity. While instances of saturation were found, the average humidity at the centers of 39 PSCs was calculated to be 58 percent. Possible reasons for this apparent discrepancy are discussed. Applying a similar approach to the Southern Hemisphere, in 1979, virtually no PSCs are found in the vortex after September 10 at 20 km. This result has important implications for a number of proposed explanations for the Antarctic ozone hole.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20010060090&hterms=NaSH&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3DNaSH','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20010060090&hterms=NaSH&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3DNaSH"><span id="translatedtitle">What Controls the Arctic Lower <span class="hlt">Stratosphere</span> Temperature?</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Newman, Paul A.; Nash, Eric R.; Einaudi, Franco (Technical Monitor)</p> <p>2000-01-01</p> <p>The temperature of the Arctic lower <span class="hlt">stratosphere</span> is critical for understanding polar ozone levels. As temperatures drop below about 195 K, polar <span class="hlt">stratospheric</span> clouds form, which then convert HCl and ClONO2 into reactive forms that are catalysts for ozone loss reactions. Hence, the lower <span class="hlt">stratospheric</span> temperature during the March period is a key parameter for understanding polar ozone losses. The temperature is basically understood to be a result of planetary waves which drive the polar temperature away from a cold "radiative equilibrium" state. This is demonstrated using NCEP/NCAR reanalysis calculations of the heat flux and the mean polar temperature. The temperature during the March period is fundamentally driven by the integrated impact of large scale waves moving from the troposphere to the <span class="hlt">stratosphere</span> during the January through February period.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19960027887','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19960027887"><span id="translatedtitle">Laboratory studies of <span class="hlt">stratospheric</span> aerosol chemistry</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Molina, Mario J.</p> <p>1996-01-01</p> <p>In this report we summarize the results of the two sets of projects funded by the NASA grant NAG2-632, namely investigations of various thermodynamic and nucleation properties of the aqueous acid system which makes up <span class="hlt">stratospheric</span> aerosols, and measurements of reaction probabilities directly on ice aerosols with sizes corresponding to those of polar <span class="hlt">stratospheric</span> cloud particles. The results of these investigations are of importance for the assessment of the potential <span class="hlt">stratospheric</span> effects of future fleets of supersonic aircraft. In particular, the results permit to better estimate the effects of increased amounts of water vapor and nitric acid (which forms from nitrogen oxides) on polar <span class="hlt">stratospheric</span> clouds and on the chemistry induced by these clouds.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li class="active"><span>18</span></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_18 --> <div id="page_19" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li class="active"><span>19</span></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="361"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008Natur.453..163D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008Natur.453..163D"><span id="translatedtitle">Planetary science: Music of the <span class="hlt">stratospheres</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Dowling, Timothy E.</p> <p>2008-05-01</p> <p>Fifteen-year oscillations in Saturn's equatorial <span class="hlt">stratosphere</span> bear a striking resemblance to the shorter-term oscillations seen on Earth and Jupiter - akin to notes played on a cello, a violin and a viola.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19900041442&hterms=denitrification&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Ddenitrification','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19900041442&hterms=denitrification&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Ddenitrification"><span id="translatedtitle">Denitrification mechanisms in the polar <span class="hlt">stratospheres</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Toon, Owen B.; Turco, R. P.; Hamill, P.</p> <p>1990-01-01</p> <p>Microphysical simulations suggest that the time required for nitric acid particles to sediment from the <span class="hlt">stratosphere</span> is comparable to the time required for falling ice particles to incorporate nitric acid vapor from the vapor phase. Since nitric acid particles form earlier in the winter than ice particles, these simulations favor denitrification being a separate process from dehydration, with denitrification being due to nitric acid particles and dehydration due to ice particles. In the simulations, the column abundance of nitric acid is only depleted if temperatures low enough for nitric acid particles to exist extend to the altitude above which the column is measured. Such low temperatures are infrequent in the Arctic lower <span class="hlt">stratosphere</span>, which may be the main reason that the Arctic <span class="hlt">stratospheric</span> column shows little loss of nitric acid during winter, while the colder Antarctic <span class="hlt">stratospheric</span> column shows a substantial loss of nitric acid.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19740028410&hterms=Ammonium+sulfate&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3DAmmonium%2Bsulfate','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19740028410&hterms=Ammonium+sulfate&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3DAmmonium%2Bsulfate"><span id="translatedtitle">Physical properties of the <span class="hlt">stratospheric</span> aerosols</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Toon, O. B.; Pollack, J. B.</p> <p>1973-01-01</p> <p>A comparison of the equilibrium vapor pressure over nitric acid solutions with observed water and nitric acid partial pressures in the <span class="hlt">stratosphere</span> implies that nitric acid cannot be present as an aerosol particle in the lower <span class="hlt">stratosphere</span>. A similar comparison for sulfuric acid solutions indicates that sulfuric acid aerosol particles are 75% H2SO4 by weight in water, in good agreement with direct observations. The freezing curve of H2SO4 solutions requires that the H2SO4 aerosol particles be solid or supercooled. The equilibrium vapor pressure of H2SO4 in the <span class="hlt">stratosphere</span> is of the order of 20 picotorr. At <span class="hlt">stratospheric</span> temperatures, ammonium sulfate is in a ferroelectric phase. As a result, polar molecules may form a surface coating on these aerosols, which may be a fertile ground for further chemical reaction.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2012AdSpR..50..906Z&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2012AdSpR..50..906Z&link_type=ABSTRACT"><span id="translatedtitle">Trajectory tracking control for underactuated <span class="hlt">stratospheric</span> airship</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zheng, Zewei; Huo, Wei; Wu, Zhe</p> <p>2012-10-01</p> <p><span class="hlt">Stratospheric</span> airship is a new kind of aerospace system which has attracted worldwide developing interests for its broad application prospects. Based on the trajectory linearization control (TLC) theory, a novel trajectory tracking control method for an underactuated <span class="hlt">stratospheric</span> airship is presented in this paper. Firstly, the TLC theory is described sketchily, and the dynamic model of the <span class="hlt">stratospheric</span> airship is introduced with kinematics and dynamics equations. Then, the trajectory tracking control strategy is deduced in detail. The designed control system possesses a cascaded structure which consists of desired attitude calculation, position control loop and attitude control loop. Two sub-loops are designed for the position and attitude control loops, respectively, including the kinematics control loop and dynamics control loop. Stability analysis shows that the controlled closed-loop system is exponentially stable. Finally, simulation results for the <span class="hlt">stratospheric</span> airship to track typical trajectories are illustrated to verify effectiveness of the proposed approach.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19800014436','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19800014436"><span id="translatedtitle">The stratcom 8 effort. [<span class="hlt">stratospheric</span> photochemistry</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Reed, E. I. (Editor)</p> <p>1980-01-01</p> <p>The ozone-nitrogen oxides ultraviolent flux interactions were investigated to obtain data on <span class="hlt">stratospheric</span> photochemistry. The balloon, rocket, and aircraft operations are described along with the instruments, parameter measurements, and payloads.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/569485','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/569485"><span id="translatedtitle">Isotopic fractionation of <span class="hlt">stratospheric</span> nitrous oxide</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Yung, Yuk L.; Miller, C.L.</p> <p>1997-12-05</p> <p>An isotopic fractionation mechanism is proposed, based on photolytic destruction to explain the {sup 15}N/{sup 14}N and {sup 18}O/{sup 16}O fractionation of <span class="hlt">stratospheric</span> nitrous oxide (N{sub 2}O) and reconcile laboratory experiments with atmospheric observations. The theory predicts that (i) the isotopomers {sup 15}N{sup 14}N{sup 16}O and {sup 14}N{sup 15}N{sup 16}O have very different isotopic fractionations in the <span class="hlt">stratosphere</span>, and (ii) laboratory photolysis experiments conducted at 205 nanometers should better simulate the observed isotopic fractionation of <span class="hlt">stratospheric</span> N{sub 2}O. Modeling results indicate that there is no compelling reason to invoke a significant chemical source of N{sub 2}O in the middle atmosphere and that individual N{sub 2}O isotopomers might be useful tracers of <span class="hlt">stratospheric</span> air parcel motion. 32 refs., 2 figs., 1 tab.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/900173','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/900173"><span id="translatedtitle"><span class="hlt">Stratospheric</span> Relaxation in IMPACT's Radiation Code</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Edis, T; Grant, K; Cameron-Smith, P</p> <p>2006-11-13</p> <p>While Impact incorporates diagnostic radiation routines from our work in previous years, it has not previously included the <span class="hlt">stratospheric</span> relaxation required for forcing calculations. We have now implemented the necessary changes for <span class="hlt">stratospheric</span> relaxation, tested its stability, and compared the results with <span class="hlt">stratosphere</span> temperatures obtained from CAM3 met data. The relaxation results in stable temperature profiles in the <span class="hlt">stratosphere</span>, which is encouraging for use in forcing calculations. It does, however, produce a cooling bias when compared to CAM3, which appears to be due to differences in radiation calculations rather than the interactive treatment of ozone. The cause of this bias is unclear as yet, but seems to be systematic and hence cancels out when differences are taken relative to a control simulation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20070035963','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20070035963"><span id="translatedtitle">SOFIA: <span class="hlt">Stratospheric</span> Observatory for Infrared Astronomy</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Becker, Eric; Kunz, Nans; Bowers, Al</p> <p>2007-01-01</p> <p>This viewgraph presentation reviews the <span class="hlt">Stratospheric</span> Observatory for Infrared Astronomy (SOFIA). The contents include: 1) Heritage & History; 2) Level 1 Requirements; 3) Top Level Overview of the Observatory; 4) Development Challenges; and 5) Highlight Photos.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20070035890','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20070035890"><span id="translatedtitle">SOFIA - <span class="hlt">Stratospheric</span> Observatory for Infrared Astronomy</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Kunz, Nans; Bowers, Al</p> <p>2007-01-01</p> <p>This viewgraph presentation reviews the <span class="hlt">Stratospheric</span> Observatory for Infrared Astronomy (SOFIA). The contents include: 1) Heritage & History; 2) Level 1 Requirements; 3) Top Level Overview of the Observatory; 4) Development Challenges; and 5) Highlight Photos.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19790035058&hterms=nitrosyl&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dnitrosyl','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19790035058&hterms=nitrosyl&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dnitrosyl"><span id="translatedtitle">Nitrogen-sulfur compounds in <span class="hlt">stratospheric</span> aerosols</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Farlow, N. H.; Snetsinger, K. G.; Hayes, D. M.; Lem, H. Y.; Tooper, B. M.</p> <p>1978-01-01</p> <p>Two forms of nitrosyl sulfuric acid (NOHSO4 and NOHS2O7) have been tentatively identified in <span class="hlt">stratospheric</span> aerosols. The first of these can be formed either directly from gas reactions of NO2 with SO2 or by gas-particle interactions between NO2 and H2SO4. The second product may form when SO3 is involved. Estimates based on these reactions suggest that the maximum quantity of NO that might be absorbed in <span class="hlt">stratospheric</span> aerosols could vary from one-third to twice the amount of NO in the surrounding air. If these reactions occur in the <span class="hlt">stratosphere</span>, then a mechanism exists for removing nitrogen oxides from that region by aerosol particle fallout. This process may typify another natural means that helps cleanse the lower <span class="hlt">stratosphere</span> of excessive pollutants.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008GeoRL..3510812B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008GeoRL..3510812B"><span id="translatedtitle">Impact of geo-engineering on the ion composition of the <span class="hlt">stratosphere</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Beig, Gufran</p> <p>2008-05-01</p> <p>A remedy called ``geo-engineering solution'' has been recently proposed by some scientists to handle the global <span class="hlt">warming</span> problem through injection of sulfates high aloft into the <span class="hlt">stratosphere</span>. However, this idea may have some other side impacts. We have investigated the perturbation caused by geo-engineering solution on the <span class="hlt">stratospheric</span> charged species using a coupled neutral-ion photochemical model. Model calculations indicate additional production of sulfuric acid immediately after the injection which further leads to increased abundance of heavy negative ion family by several orders of magnitude over the ambient. After 2 months, most of the H2SO4 vapor condensed to H2SO4 aerosols and the density of charged aerosol increases several folds and the effect spread further in the tropics. The perturbation in ionic species spread globally after about 1 year but became weaker in magnitude. The ion perturbation has implications on the electrical properties of the atmospheric medium.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19820026810&hterms=cyanide&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dcyanide','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19820026810&hterms=cyanide&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dcyanide"><span id="translatedtitle">Spectroscopic detection of <span class="hlt">stratospheric</span> hydrogen cyanide</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Coffey, M. T.; Mankin, W. G.; Cicerone, R. J.</p> <p>1981-01-01</p> <p>A number of features have been identified as absorption lines of hydrogen cyanide in infrared spectra of <span class="hlt">stratospheric</span> absorption obtained from a high-altitude aircraft. Column amounts of <span class="hlt">stratospheric</span> hydrogen cyanide have been derived from spectra recorded on eight flights. The average vertical column amount above 12 kilometers is 7.1 + or - 0.8 x 10 to the 14th molecules per square centimeter, corresponding to an average mixing ratio of 170 parts per trillion by volume.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/15496919','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/15496919"><span id="translatedtitle">Extreme climate of the global troposphere and <span class="hlt">stratosphere</span> in 1940-42 related to El Niño.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Brönnimann, S; Luterbacher, J; Staehelin, J; Svendby, T M; Hansen, G; Svenøe, T</p> <p>2004-10-21</p> <p>Although the El Niño/Southern Oscillation phenomenon is the most prominent mode of climate variability and affects weather and climate in large parts of the world, its effects on Europe and the high-latitude <span class="hlt">stratosphere</span> are controversial. Using historical observations and reconstruction techniques, we analyse the anomalous state of the troposphere and <span class="hlt">stratosphere</span> in the Northern Hemisphere from 1940 to 1942 that occurred during a strong and long-lasting El Niño event. Exceptionally low surface temperatures in Europe and the north Pacific Ocean coincided with high temperatures in Alaska. In the lower <span class="hlt">stratosphere</span>, our reconstructions show high temperatures over northern Eurasia and the north Pacific Ocean, and a weak polar vortex. In addition, there is observational evidence for frequent <span class="hlt">stratospheric</span> <span class="hlt">warmings</span> and high column ozone at Arctic and mid-latitude sites. We compare our historical data for the period 1940-42 with more recent data and a 650-year climate model simulation. We conclude that the observed anomalies constitute a recurring extreme state of the global troposphere-<span class="hlt">stratosphere</span> system in northern winter that is related to strong El Niño events. PMID:15496919</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016JGRD..121.3388N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016JGRD..121.3388N"><span id="translatedtitle">Predictability of the <span class="hlt">stratospheric</span> polar vortex breakdown: An ensemble reforecast experiment for the splitting event in January 2009</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Noguchi, Shunsuke; Mukougawa, Hitoshi; Kuroda, Yuhji; Mizuta, Ryo; Yabu, Shoukichi; Yoshimura, Hiromasa</p> <p>2016-04-01</p> <p>A series of ensemble reforecast experiments is conducted to investigate the predictability and the occurrence mechanism of a <span class="hlt">stratospheric</span> sudden <span class="hlt">warming</span> occurred in late January 2009, which is a typical polar vortex splitting event. To fully examine the rapid vortex splitting evolution and predictability variation, ensemble forecasts are carried out every day during January 2009. The vortex splitting event is reliably predicted by forecasts initialized after 6 days prior to the vortex breakup. It is also found that the propagating property of planetary waves within the <span class="hlt">stratosphere</span> is a key to the successful prediction for the vortex splitting event. Planetary waves incoming from the troposphere are reflected back into the troposphere for failed forecasts, whereas they are absorbed within the <span class="hlt">stratosphere</span> for succeeded forecasts. Composite analysis reveals the following reflection process of planetary waves for the failed forecast: Upward propagation of planetary wave activity from a tropospheric blocking over Alaska is weaker during initial prediction periods; then, the deceleration of the zonal wind in the upper <span class="hlt">stratosphere</span> becomes weaker over Europe, which produces a preferable condition for the wave reflection; hence, subsequently incoming wave activity from the troposphere over Europe is reflected back over the Siberia inducing the eastward phase tilt of planetary waves, which shuts down the further upward propagation of planetary waves leading to the vortex splitting. Thus, this study shows that the <span class="hlt">stratospheric</span> condition would be another important control factor for the occurrence of the vortex splitting event, besides anomalous tropospheric circulations enforcing upward propagation of planetary waves.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016EGUGA..1813966S&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016EGUGA..1813966S&link_type=ABSTRACT"><span id="translatedtitle">Injection of iodine to the <span class="hlt">stratosphere</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Saiz-Lopez, Alfonso; Baidar, Sunil; Cuevas, Carlos A.; Koening, Theodore; Fernandez, Rafael P.; Dix, Barbara; Kinnison, Douglas E.; Lamarque, Jean-Francois; Rodriguez-Lloveras, Xavier; Campos, Teresa L.; Volkamer, Rainer</p> <p>2016-04-01</p> <p>There are still many uncertainties about the influence of iodine chemistry in the <span class="hlt">stratosphere</span>, as the real amount of reactive iodine injected to this layer the troposphere and the partitioning of iodine species are still unknown. In this work we report a new estimation of the injection of iodine into the <span class="hlt">stratosphere</span> based on novel daytime (SZA < 45°) aircraft observations in the tropical tropopause layer (TORERO campaign) and a 3D global chemistry-climate model (CAM-Chem) with the most recent knowledge about iodine photochemistry. The results indicate that significant levels of total reactive iodine (0.25-0.7 pptv), between 2 and 5 times larger than the accepted upper limits, could be injected into the <span class="hlt">stratosphere</span> via tropical convective outflow. At these iodine levels, modelled iodine catalytic cycles account for up to 30% of the contemporary ozone loss in the tropical lower <span class="hlt">stratosphere</span> and can exert a <span class="hlt">stratospheric</span> ozone depletion potential equivalent or even larger than that of very short-lived bromocarbons. Therefore, we suggest that iodine sources and chemistry need to be considered in assessments of the historical and future evolution of the <span class="hlt">stratospheric</span> ozone layer.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2006AGUSM.A44C..05S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2006AGUSM.A44C..05S"><span id="translatedtitle">How Model Differences in <span class="hlt">Stratospheric</span> Transport can Influence Polar Ozone Recovery</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Strahan, S. E.; Douglass, A. R.; Stolarski, R. S.</p> <p>2006-05-01</p> <p>We examine 3 Global Modeling Initiative (GMI) chemistry and transport simulations that have the same WMO A2 source gas boundary conditions for 1980-2025 but different <span class="hlt">stratospheric</span> circulations and Arctic temperatures. We examine the evolution of Cly in each polar vortex and compare the models' ozone response. Two simulations of the GMI <span class="hlt">stratospheric</span> model were run at 2ox2.5o resolution. One had a repeating cold Arctic winter with abundant PSCs; the other had a repeating dynamically active, <span class="hlt">warm</span> winter with almost no PSCs. Maximum Cly in the cold simulation was 2.9 ppb in 2000 and was slightly lower in the <span class="hlt">warm</span> simulation. The cold winter showed greater sensitivity to Cly and consequently recovered at a faster rate. Nevertheless, both are projected to recover at about the same time. The factors controlling recovery are the halogen boundary condition and mean <span class="hlt">stratospheric</span> circulation (i.e., age of air), both of which are nearly the same in these simulations. The differences between these simulations demonstrate that interannual variation in transport will play a large role in the appearance of Arctic ozone recovery. Age of air is a diagnostic for <span class="hlt">stratospheric</span> circulation, but it does not assess the credibility of specific model transport processes. We compare the two simulations above with a GMI simulation run at 4ox5o resolution. All 3 models compare extremely well with mean age determined from aircraft CO2, but the lower resolution model has considerably lower vortex Cly. The low Cly is caused by a leaky vortex which leads to two credibility problems: the leaky vortex can't produce near complete O3 loss because it doesn't maintain the necessary high levels of Cly, and the leakiness causes the model to respond faster to reductions in chlorine, allowing it return to 1980 levels sooner. Models used to predict ozone recovery need to demonstrate a strong Antarctic mixing barrier.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20000011670&hterms=Greenhouse+effect+Atmospheric&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3D%2528%2528Greenhouse%2Beffect%2529%2BAtmospheric%2529','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20000011670&hterms=Greenhouse+effect+Atmospheric&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3D%2528%2528Greenhouse%2Beffect%2529%2BAtmospheric%2529"><span id="translatedtitle">An Estimation of the Climatic Effects of <span class="hlt">Stratospheric</span> Ozone Losses during the 1980s. Appendix K</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>MacKay, Robert M.; Ko, Malcolm K. W.; Shia, Run-Lie; Yang, Yajaing; Zhou, Shuntai; Molnar, Gyula</p> <p>1997-01-01</p> <p>In order to study the potential climatic effects of the ozone hole more directly and to assess the validity of previous lower resolution model results, the latest high spatial resolution version of the Atmospheric and Environmental Research, Inc., seasonal radiative dynamical climate model is used to simulate the climatic effects of ozone changes relative to the other greenhouse gases. The steady-state climatic effect of a sustained decrease in lower <span class="hlt">stratospheric</span> ozone, similar in magnitude to the observed 1979-90 decrease, is estimated by comparing three steady-state climate simulations: 1) 1979 greenhouse gas concentrations and 1979 ozone, II) 1990 greenhouse gas concentrations with 1979 ozone, and III) 1990 greenhouse gas concentrations with 1990 ozone. The simulated increase in surface air temperature resulting from nonozone greenhouse gases is 0.272 K. When changes in lower <span class="hlt">stratospheric</span> ozone are included, the greenhouse <span class="hlt">warming</span> is 0.165 K, which is approximately 39% lower than when ozone is fixed at the 1979 concentrations. Ozone perturbations at high latitudes result in a cooling of the surface-troposphere system that is greater (by a factor of 2.8) than that estimated from the change in radiative forcing resulting from ozone depiction and the model's 2 x CO, climate sensitivity. The results suggest that changes in meridional heat transport from low to high latitudes combined with the decrease in the infrared opacity of the lower <span class="hlt">stratosphere</span> are very important in determining the steady-state response to high latitude ozone losses. The 39% compensation in greenhouse <span class="hlt">warming</span> resulting from lower <span class="hlt">stratospheric</span> ozone losses is also larger than the 28% compensation simulated previously by the lower resolution model. The higher resolution model is able to resolve the high latitude features of the assumed ozone perturbation, which are important in determining the overall climate sensitivity to these perturbations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://eric.ed.gov/?q=dinosaur&pg=4&id=EJ658270','ERIC'); return false;" href="http://eric.ed.gov/?q=dinosaur&pg=4&id=EJ658270"><span id="translatedtitle"><span class="hlt">Warm</span> and Cool Dinosaurs.</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Mannlein, Sally</p> <p>2001-01-01</p> <p>Presents an art activity in which first grade students draw dinosaurs in order to learn about the concept of <span class="hlt">warm</span> and cool colors. Explains how the activity also helped the students learn about the concept of distance when drawing. (CMK)</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/46040','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/46040"><span id="translatedtitle">Global <span class="hlt">warming</span> elucidated</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Shen, S.</p> <p>1995-03-01</p> <p>The meaning of global <span class="hlt">warming</span> and its relevance to everyday life is explained. Simple thermodynamics is used to predict an oscillatory nature of the change in climate due to global <span class="hlt">warming</span>. Global <span class="hlt">warming</span> causes extreme events and bad weather in the near term. In the long term it may cause the earth to transition to another equilibrium state through many oscillation in climatic patterns. The magnitudes of these oscillations could easily exceed the difference between the end points. The author further explains why many no longer fully understands the nature and magnitudes of common phenomena such as storms and wind speeds because of these oscillations, and the absorptive properties of clouds. The author links the increase in duration of the El Nino to global <span class="hlt">warming</span>, and further predicts public health risks as the earth transitions to another equilibrium state in its young history.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20150000726','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20150000726"><span id="translatedtitle">Reconciling <span class="hlt">Warming</span> Trends</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Schmidt, Gavin A.; Shindell, Drew T.; Tsigaridis, Konstantinos</p> <p>2014-01-01</p> <p>Climate models projected stronger <span class="hlt">warming</span> over the past 15 years than has been seen in observations. Conspiring factors of errors in volcanic and solar inputs, representations of aerosols, and El NiNo evolution, may explain most of the discrepancy.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li class="active"><span>19</span></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_19 --> <div id="page_20" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li class="active"><span>20</span></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="381"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016JGRD..121.8067A&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016JGRD..121.8067A&link_type=ABSTRACT"><span id="translatedtitle">Isolating the roles of different forcing agents in global <span class="hlt">stratospheric</span> temperature changes using model integrations with incrementally added single forcings</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Aquila, V.; Swartz, W. H.; Waugh, D. W.; Colarco, P. R.; Pawson, S.; Polvani, L. M.; Stolarski, R. S.</p> <p>2016-07-01</p> <p>Satellite instruments show a cooling of global <span class="hlt">stratospheric</span> temperatures over the whole data record (1979-2014). This cooling is not linear and includes two descending steps in the early 1980s and mid-1990s. The 1979-1995 period is characterized by increasing concentrations of ozone-depleting substances (ODSs) and by the two major volcanic eruptions of El Chichón (1982) and Mount Pinatubo (1991). The 1995-present period is characterized by decreasing ODS concentrations and by the absence of major volcanic eruptions. Greenhouse gas (GHG) concentrations increase over the whole time period. In order to isolate the roles of different forcing agents in the global <span class="hlt">stratospheric</span> temperature changes, we performed a set of simulations using the NASA Goddard Earth Observing System Chemistry-Climate Model with prescribed sea surface temperatures. We find that in our model simulations the cooling of the <span class="hlt">stratosphere</span> from 1979 to present is mostly driven by changes in GHG concentrations in the middle and upper <span class="hlt">stratosphere</span> and by GHG and ODS changes in the lower <span class="hlt">stratosphere</span>. While the cooling trend caused by increasing GHGs is roughly constant over the satellite era, changing ODS concentrations cause a significant <span class="hlt">stratospheric</span> cooling only up to the mid-1990s, when they start to decrease because of the implementation of the Montreal Protocol. Sporadic volcanic events and the solar cycle have a distinct signature in the time series of <span class="hlt">stratospheric</span> temperature anomalies but do not play a statistically significant role in the long-term trends from 1979 to 2014. Several factors combine to produce the step-like behavior in the <span class="hlt">stratospheric</span> temperatures: in the lower <span class="hlt">stratosphere</span>, the flattening starting in the mid-1990s is due to the decrease in ozone-depleting substances; Mount Pinatubo and the solar cycle cause the abrupt steps through the aerosol-associated <span class="hlt">warming</span> and the volcanically induced ozone depletion. In the middle and upper <span class="hlt">stratosphere</span>, changes in solar</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1994PhDT........71L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1994PhDT........71L"><span id="translatedtitle">Issues in <span class="hlt">Stratospheric</span> Ozone Depletion.</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lloyd, Steven Andrew</p> <p></p> <p>Following the announcement of the discovery of the Antarctic ozone hole in 1985 there have arisen a multitude of questions pertaining to the nature and consequences of polar ozone depletion. This thesis addresses several of these specific questions, using both computer models of chemical kinetics and the Earth's radiation field as well as laboratory kinetic experiments. A coupled chemical kinetic-radiative numerical model was developed to assist in the analysis of in situ field measurements of several radical and neutral species in the polar and mid-latitude lower <span class="hlt">stratosphere</span>. Modeling was used in the analysis of enhanced polar ClO, mid-latitude diurnal variation of ClO, and simultaneous measurements of OH, HO_2, H_2 O and O_3. Most importantly, such modeling was instrumental in establishing the link between the observed ClO and BrO concentrations in the Antarctic polar vortex and the observed rate of ozone depletion. The principal medical concern of <span class="hlt">stratospheric</span> ozone depletion is that ozone loss will lead to the enhancement of ground-level UV-B radiation. Global ozone climatology (40^circS to 50^ circN latitude) was incorporated into a radiation field model to calculate the biologically accumulated dosage (BAD) of UV-B radiation, integrated over days, months, and years. The slope of the annual BAD as a function of latitude was found to correspond to epidemiological data for non-melanoma skin cancers for 30^circ -50^circN. Various ozone loss scenarios were investigated. It was found that a small ozone loss in the tropics can provide as much additional biologically effective UV-B as a much larger ozone loss at higher latitudes. Also, for ozone depletions of > 5%, the BAD of UV-B increases exponentially with decreasing ozone levels. An important key player in determining whether polar ozone depletion can propagate into the populated mid-latitudes is chlorine nitrate, ClONO_2 . As yet this molecule is only indirectly accounted for in computer models and field</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013JGRD..118.4533C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013JGRD..118.4533C"><span id="translatedtitle">Microphysical and radiative changes in cirrus clouds by geoengineering the <span class="hlt">stratosphere</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Cirisan, A.; Spichtinger, P.; Luo, B. P.; Weisenstein, D. K.; Wernli, H.; Lohmann, U.; Peter, T.</p> <p>2013-05-01</p> <p>In the absence of tangible progress in reducing greenhouse gas emissions, the implementation of solar radiation management has been suggested as measure to stop global <span class="hlt">warming</span>. Here we investigate the impacts on northern midlatitude cirrus from continuous SO2emissions of 2-10 Mt/a in the tropical <span class="hlt">stratosphere</span>. Transport of geoengineering aerosols into the troposphere was calculated along trajectories based on ERA Interim reanalyses using ozone concentrations to quantify the degree of mixing of <span class="hlt">stratospheric</span> and tropospheric air termed "troposphericity". Modeled size distributions of the geoengineered H2SO4-H2O droplets have been fed into a cirrus box model with spectral microphysics. The geoengineering is predicted to cause changes in ice number density by up to 50%, depending on troposphericity and cooling rate. We estimate the resulting cloud radiative effects from a radiation transfer model. Complex interplay between the few large <span class="hlt">stratospheric</span> and many small tropospheric H2SO4-H2O droplets gives rise to partly counteracting radiative effects: local increases in cloud radiative forcing up to +2 W/m2for low troposphericities and slow cooling rates, and decreases up to -7.5 W/m2for high troposphericities and fast cooling rates. The resulting mean impact on the northern midlatitudes by changes in cirrus is predicted to be low, namely <1% of the intended radiative forcing by the <span class="hlt">stratospheric</span> aerosols. This suggests that <span class="hlt">stratospheric</span> sulphate geoengineering is unlikely to have large microphysical effects on the mean cirrus radiative forcing. However, this study disregards feedbacks, such as temperature and humidity changes in the upper troposphere, which must be examined separately.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EGUGA..1813549D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EGUGA..1813549D"><span id="translatedtitle">Precursors of weak <span class="hlt">stratospheric</span> polar vortex events: intra-seasonal variability</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Díaz-Durán, Adelaida; Ayarzagüena, Blanca; Serrano, Encarna; Ábalos, Marta; de la Camara, Álvaro</p> <p>2016-04-01</p> <p>It is known that changes in the strength of <span class="hlt">stratospheric</span> polar vortex are related to forcings that can affect the tropospheric upward wave propagation. In particular, an anomalous weak polar vortex (WPV) is preceded by a strong wave activity from the troposphere into the <span class="hlt">stratosphere</span> causing a <span class="hlt">warming</span> over the polar region and a consequent weakening of the polar cyclonic circulation. El Niño-Southern Oscillation (ENSO), Quasi-Biennial Oscillation (QBO) or certain tropospheric anomalous circulation structure, among others, have been identified in many studies as potential precursors of WPV events. However, although the timing of the most effective impact of those precursors on the <span class="hlt">stratospheric</span> polar vortex is already known, the generation of WPV events at any given time of winter is still unknown in detail. The aim of this work is to explore the WPV occurred in different boreal winter sub-seasons and their possible precursors. Namely, we consider early winter (from October to December), mid-winter (January and February) and late winter (March and April) separately. For this purpose, we use daily-mean data from ERA-Interim for the period 1979-2011. Preliminary results by the authors give evidence of intra-winter variability in the state of the polar <span class="hlt">stratosphere</span> prior to WPV events, in the characteristics of the anomalous wave activity triggering them and in the tropospheric circulation structures related to this enhancement of wave activity. In this work we show that mid- and late winter WPV events are preceded by an anomalously strong vortex and a peak of high wave activity with relevant contribution of wavenumber-1 and wavenumber-2 components. In contrast, a preconditioning in the <span class="hlt">stratosphere</span> is observed for early winter WPVs, which are preceded by a weak enhancement of wavenumber-1 wave activity. The contribution of precursors of WVP events, such as QBO, Arctic sea ice anomalies or ENSO, presents differences among the three winter sub-seasons.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFM.A43E0324G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFM.A43E0324G"><span id="translatedtitle">Quantifying the Summertime Austral Jet Stream and Hadley Cell Response to <span class="hlt">Stratospheric</span> Ozone and Greenhouse Gases</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gerber, E. P.; Son, S.</p> <p>2013-12-01</p> <p>The impact of anthropogenic forcing on the austral jet stream and Hadley Cell in summer is assessed across three comprehensive climate model datasets, the Chemistry Climate Model Validation Activity 2 (CCMVal2) and Coupled Model Intercomparison Projects, Phases 3 and 5 (CMIP3,5). Changes in <span class="hlt">stratospheric</span> ozone and greenhouse gases impact the troposphere in this season, and a simple framework based on temperature trends in the lower polar <span class="hlt">stratosphere</span> and upper tropical troposphere is developed to separate their effects. It suggests that Southern Hemisphere circulation trends are driven by changes in upper troposphere/lower <span class="hlt">stratosphere</span> temperature gradients: the subtropical and extratropical jets respond similarly when the tropics <span class="hlt">warm</span> or the polar <span class="hlt">stratosphere</span> cools. The mean circulation response to greenhouse gases and ozone is fairly comparable across the three multimodel datasets; consistent with previous studies, ozone has dominated changes in recent decades, while in the future, ozone and greenhouse gases will largely offset each other. The multimodel mean perspective, however, masks considerable spread between individual models. Uncertainty resulting from differences in temperature trends is separated from differences in the circulation response to a given temperature change. Both sources of uncertainty contribute equally to model spread. Uncertainty in temperature trends is dominated by differences in the polar <span class="hlt">stratosphere</span>, not the tropics, suggesting that reducing uncertainty in models' climate sensitivity may not narrow the spread in subtropical and extratropical circulation trends in this season. Rather, the ozone forcing must be constrained. Even if the temperature trends could be perfectly constrained, however, models' 'circulation sensitivity,' differences in the response of the circulation to the same thermal forcing, must be addressed in order to narrow spread in climate projections.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19920006243','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19920006243"><span id="translatedtitle">Trends in <span class="hlt">stratospheric</span> minor constituents</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Stolarski, R. S.; Chu, W. P.; Coffey, M. T.; Heaps, W. S.; Kaye, J. A.; Mccormick, M. P.; Zander, R.</p> <p>1989-01-01</p> <p>Photochemical models predict that increasing source gas concentrations are also expected to lead to changes in the concentrations of both catalytically active radical species (such as NO2, ClO, and OH) and inactive reservoir species (such as HNO3, HCl, and H2O). For simplicity, we will refer to all these as trace species. Those species that are expected to have increasing concentration levels are investigated. Additionally, the trace species concentration levels are monitored for unexpected changes on the basis of the measure increase in source gases. Carrying out these investigations is difficult due to the limited data base of measurements of <span class="hlt">stratospheric</span> trace species. In situ measurements are made only infrequently, and there are few satelliteborne measurements, most over a time space insufficient for trend determination. Instead, ground-based measurements of column content must be used for many species, and interpretation is complicated by contributions from the troposphere or mesosphere or both. In this chapter, we examine existing measurements as published or tabulated.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19800035571&hterms=pollution+Marina&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dpollution%2BMarina','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19800035571&hterms=pollution+Marina&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dpollution%2BMarina"><span id="translatedtitle">OCS, <span class="hlt">stratospheric</span> aerosols and climate</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Turco, R. P.; Whitten, R. C.; Toon, O. B.; Pollack, J. B.; Hamill, P.</p> <p>1980-01-01</p> <p>The carbonyl sulfide budget in the atmosphere is examined, and the effects of <span class="hlt">stratospheric</span> sulfate aerosol particles, formed in part from atmospheric carbonyl sulfate, on global climate are considered. From tropospheric measurements of carbon disulfide and the rate constant for the conversion of carbon disulfide to carbonyl sulfide, it is estimated that five Tg of carbonyl sulfide/year could be generated from carbon disulfide in the atmosphere. Direct sources of OCS include the refining and combustion of fossil fuels (1 Tg/year), natural and agricultural fires (0.2 to 0.3 Tg/year), and soils (0.5 Tg/year), yielding a total influx of from 1 to 10 Tg/year, up to 50% of which may be anthropogenic. Considerations of carbonyl sulfide sinks and concentrations indicate an atmospheric lifetime of one year, with OCS the major atmospheric sulfur compound. It is estimated that a ten-fold increase in atmospheric carbonyl sulfide would cause an optical depth perturbation comparable to that of a modest volcanic eruption, leading to an average global surface temperature decrease of 0.1 K, in addition to a possible greenhouse effect.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014ACP....1413705K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014ACP....1413705K"><span id="translatedtitle">The impact of polar <span class="hlt">stratospheric</span> ozone loss on Southern Hemisphere <span class="hlt">stratospheric</span> circulation and climate</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Keeble, J.; Braesicke, P.; Abraham, N. L.; Roscoe, H. K.; Pyle, J. A.</p> <p>2014-12-01</p> <p>The impact of polar <span class="hlt">stratospheric</span> ozone loss resulting from chlorine activation on polar <span class="hlt">stratospheric</span> clouds is examined using a pair of model integrations run with the fully coupled chemistry climate model UM-UKCA. Suppressing chlorine activation through heterogeneous reactions is found to produce modelled ozone differences consistent with observed ozone differences between the present and pre-ozone hole period. Statistically significant high-latitude Southern Hemisphere (SH) ozone loss begins in August and peaks in October-November, with > 75% of ozone destroyed at 50 hPa. Associated with this ozone destruction is a > 12 K decrease of the lower polar <span class="hlt">stratospheric</span> temperatures and an increase of > 6 K in the upper <span class="hlt">stratosphere</span>. The heating components of this temperature change are diagnosed and it is found that the temperature dipole is the result of decreased short-wave heating in the lower <span class="hlt">stratosphere</span> and increased dynamical heating in the upper <span class="hlt">stratosphere</span>. The cooling of the polar lower <span class="hlt">stratosphere</span> leads, through thermal wind balance, to an acceleration of the polar vortex and delays its breakdown by ~ 2 weeks. A link between lower <span class="hlt">stratospheric</span> zonal wind speed, the vertical component of the Eliassen-Palm (EP) flux, Fz and the residual mean vertical circulation, <span style="border-top: 1px solid #000; color: #000;">w*, is identified. In November and December, increased westerly winds and a delay in the breakup of the polar vortex lead to increases in Fz, indicating increased wave activity entering the <span class="hlt">stratosphere</span> and propagating to higher altitudes. The resulting increase in wave breaking, diagnosed by decreases to the EP flux divergence, drives enhanced downwelling over the polar cap. Many of the <span class="hlt">stratospheric</span> signals modelled in this study propagate down to the troposphere, and lead to significant surface changes in December.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/153561','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/153561"><span id="translatedtitle">Long range global <span class="hlt">warming</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Rolle, K.C.; Pulkrabek, W.W.; Fiedler, R.A.</p> <p>1995-12-31</p> <p>This paper explores one of the causes of global <span class="hlt">warming</span> that is often overlooked, the direct heating of the environment by engineering systems. Most research and studies of global <span class="hlt">warming</span> concentrate on the modification that is occurring to atmospheric air as a result of pollution gases being added by various systems; i.e., refrigerants, nitrogen oxides, ozone, hydrocarbons, halon, and others. This modification affects the thermal radiation balance between earth, sun and space, resulting in a decrease of radiation outflow and a slow rise in the earth`s steady state temperature. For this reason the solution to the problem is perceived as one of cleaning up the processes and effluents that are discharged into the environment. In this paper arguments are presented that suggest, that there is a far more serious cause for global <span class="hlt">warming</span> that will manifest itself in the next two or three centuries; direct heating from the exponential growth of energy usage by humankind. Because this is a minor contributor to the global <span class="hlt">warming</span> problem at present, it is overlooked or ignored. Energy use from the combustion of fuels and from the output of nuclear reactions eventually is manifest as <span class="hlt">warming</span> of the surroundings. Thus, as energy is used at an ever increasing rate the consequent global <span class="hlt">warming</span> also increases at an ever increasing rate. Eventually this rate will become equal to a few percent of solar radiation. When this happens the earth`s temperature will have risen by several degrees with catastrophic results. The trends in world energy use are reviewed and some mathematical models are presented to suggest future scenarios. These models can be used to predict when the global <span class="hlt">warming</span> problem will become undeniably apparent, when it will become critical, and when it will become catastrophic.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/245289','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/245289"><span id="translatedtitle"><span class="hlt">Warm</span> up to the idea: Global <span class="hlt">warming</span> is here</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Lynch, C.F.</p> <p>1996-07-01</p> <p>This article summarizes recent information about global <span class="hlt">warming</span> as well as the history of greenhouse gas emissions which have lead to more and more evidence of global <span class="hlt">warming</span>. The primary source detailed is the second major study report on global <span class="hlt">warming</span> by the Intergovernmental Panel on climate change. Along with comments about the environmental effects of global <span class="hlt">warming</span> such as coastline submersion, the economic, social and political aspects of alleviating greenhouse emissions and the threat of global <span class="hlt">warming</span> are discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/45767','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/45767"><span id="translatedtitle">Ozone depletion and global <span class="hlt">warming</span> potentials of CF3I</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Solomon, S.; Burkholder, J.B.; Ravishankara, A.R.; Garcia, R.R. |</p> <p>1994-10-01</p> <p>Laboratory measurements of the infrared and near-ultraviolet absorption characteristics of CF3I (a potentially useful substitute for halons) are presented. Using these data together with a detailed photochemical model, it is shown that the lifetime of this gas in the sunlit atmosphere is less than a day. The chemistry of iodine in the <span class="hlt">stratosphere</span> is evaluated, and it is shown that any iodine that reaches the <span class="hlt">stratosphere</span> will be very effective for ozone destruction there. However, the extremely short lifetime of CF3I greatly limits its transport to the <span class="hlt">stratosphere</span> when released at the surface, especially at midlatitudes, and the total anthropogenic surface release of CF3I is likely to be far less than that of natural iodocarbons such as CH3I on a global basis. It is highly probable that the steady-state ozone depletion potential (ODP) of CF3I for surface releases is less than 0.008 and more likely below 0.0001. Measured infrared absorption data are also combined with the lifetime to show that the 20-year global <span class="hlt">warming</span> potential (GWP) of this gas is likely to be very small, less than 5. Therefore, this study suggests that neither the ODP nor the GWP of this gas represent significant obstacles to its use as a replacement for halons.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19850044877&hterms=process+global+warming&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dprocess%2Bglobal%2Bwarming','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19850044877&hterms=process+global+warming&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dprocess%2Bglobal%2Bwarming"><span id="translatedtitle">Recent advances in understanding <span class="hlt">stratospheric</span> dynamics and transport processes - Application of satellite data to their interpretation</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Grose, W. L.</p> <p>1984-01-01</p> <p>The present paper discusses the use of the transformed Eulerian (or 'residual') mean-flow formulation, the Eliassen-Palm flux, and Ertel's potential vorticity to provide an increased understanding of wave, mean-flow interactions, and constituent transport processes in the <span class="hlt">stratosphere</span>. Temperature and ozone data retrieved from radiance profiles obtained by the LIMS instrument on the Nimbus 7 satellite are utilized in conjunction with these theoretical concepts for the interpretation of phenomena that occurred during the major and minor <span class="hlt">warmings</span> of January-February 1979. The results illustrate the insight provided by these concepts and demonstrate that useful diagnostic quantities can be derived from global satellite temperature fields.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015AGUFM.A13C0334W&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015AGUFM.A13C0334W&link_type=ABSTRACT"><span id="translatedtitle">Long-term changes in the relationship between <span class="hlt">stratospheric</span> circulation and East Asian Winter Monsoon</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wei, K.</p> <p>2015-12-01</p> <p>Using two generations of reanalysis datasets from the NCAR, ECMWF, and JMA, we showed that on the interannual timescale the two leading modes of the East Asian winter monsoon (EAWM) are associated with tropospheric annular mode (AM) and <span class="hlt">stratospheric</span> polar vortex (SPV), respectively. The relationship between AM and the first EAWM mode remained stable during 1958 to 2013, whereas that between SPV and the second EAWM mode increased since the late 1980s. The SPV-related circulation and planetary wave activities are intensified in the latter period. We suggested that this change might be caused by the global <span class="hlt">warming</span> and ozone depletion.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015EGUGA..1710691K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015EGUGA..1710691K"><span id="translatedtitle"><span class="hlt">Stratospheric</span> Pathways to Enhanced Persistence of European Surface Temperatures</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kolstad, Erik W.; Sobolowski, Stefan P.; Scaife, Adam A.</p> <p>2015-04-01</p> <p>In recent years, severe weather anomalies in Europe have received considerable attention, mostly due to their detrimental impacts on human and natural systems, but also because of the apparent persistence of weather patterns over weeks and even months. The cold winter of 2009-2010 is a case in point. It is of great interest to improve our ability to forecast such events. Weather forecasts at mid-latitudes generally show low skill beyond 5-10 days ahead, but long-range forecast skill may increase during tropospheric blocking or sudden <span class="hlt">stratospheric</span> <span class="hlt">warmings</span>, which appear to affect midlatitude weather out to several weeks ahead. Here we use a simple approach to identify previously undocumented persistence in northern European summer and winter temperature anomalies in an ensemble of 18 pre-industrial climate model simulations, corroborated by actual observations. For instance, the probability of experiencing cold anomalies in February to April when the preceding months are anomalously cold and have a weak polar vortex is raised threefold compared to when the preceding months are not cold and the vortex is not weak. The persistence is observed irrespective of the data source or driving mechanisms, but is always enhanced when the <span class="hlt">stratospheric</span> polar vortex or the NAO is also perturbed. Another interesting result is that an existing surface temperature anomaly is a necessary precondition; a weak vortex alone is a relatively poor predictor on the intraseasonal time scales considered here. Our results have a potential to conditionally improve the skill of long-range forecasts and to enhance recent advancements in dynamical seasonal prediction.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014DPS....4650809S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014DPS....4650809S"><span id="translatedtitle">An exploration of Saturn's <span class="hlt">stratospheric</span> dynamics through Global Climate Modeling</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Spiga, Aymeric; Guerlet, Sandrine; Indurain, Mikel; Millour, Ehouarn; Sylvestre, Mélody; Thierry, Fouchet; Meurdesoif, Yann; Thomas, Dubos</p> <p>2014-11-01</p> <p>A decade of Cassini observations has yielded a new vision on the dynamical phenomena in Saturn's troposphere and <span class="hlt">stratosphere</span>. Several puzzling signatures (equatorial oscillations with a period of about half a Saturn year, interhemispheric circulations affecting the hydrocarbons’ distribution, including possible effects of rings shadowing, sudden <span class="hlt">warming</span> associated with the powerful 2010 Great White Spot) cannot be explained by current photochemical and radiative models, which do not include dynamics. We therefore suspect that 1. the observed anomalies arise from large-scale dynamical circulations and 2. those large-scale dynamical motions are driven by atmospheric waves, eddies, and convection, in other words fundamental mechanisms giving birth to, e.g., the Quasi-Biennal Oscillation and Brewer-Dobson circulation in the Earth’s middle atmosphere. We explore the plausibility of this scenario using our new Global Climate Modeling (GCM) for Saturn. To build this model, we firstly formulated dedicated physical parameterizations for Saturn’s atmosphere, with a particular emphasis on radiative computations (using a correlated-k radiative transfer model, with radiative species and spectral discretization tailored for Saturn) aimed at both efficiency and accuracy, and validated them against existing Cassini observations. A second step consisted in coupling this radiative model to an hydrodynamical solver to predict the three-dimensional evolution of Saturn's tropospheric and <span class="hlt">stratospheric</span> flow. We will provide an analysis of the first results of those dynamical simulations, with a focus on the development of baroclinic and barotropic instability, on eddy vs. mean flow interactions, and how this could relate to the enigmatic signatures observed by Cassini. Preliminary high-resolution simulations with a new icosahedral dynamical solver adapted to high-performance computing will also be analyzed. Perspectives are twofold: firstly, broadening our fundamental knowledge</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015AGUFM.A51C0068P&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015AGUFM.A51C0068P&link_type=ABSTRACT"><span id="translatedtitle">Ozone Radiative Feedback in Global <span class="hlt">Warming</span> Simulations with CO2 and non-CO2 Forcings</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ponater, M.; Rieger, V.; Dietmüller, S.</p> <p>2015-12-01</p> <p>It has been found that ozone radiative feedback acts to reduce the climate sensitivity in global <span class="hlt">warming</span> simulations including interactive atmospheric chemistry, if the radiative forcing origins from CO2 increase. The effect can be traced to a negative feedback from <span class="hlt">stratospheric</span> ozone changes and it is amplified by a reduced positive feedback from <span class="hlt">stratospheric</span> water vapor.These findings cannot be simply transferred to simulations in which the <span class="hlt">warming</span> is driven by a non-CO2 radiative forcing. Using a perturbation of surface NOx and CO emissions as an example, we demonstrate that a tropospheric ozone feedback may have significant impacts on physical feedbacks. These interactions can act to an extent that the effect of a negative ozone feedback can be reversed by changes in other feedbacks, thus increasing the climate sensitivity instead of reducing it. We also address some conceptual issues showing up as chemical feedbacks are added to set of physical feedbacks in simulation with interactive chemistry.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016GeoRL..43.5851K&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016GeoRL..43.5851K&link_type=ABSTRACT"><span id="translatedtitle">Climate change reduces <span class="hlt">warming</span> potential of nitrous oxide by an enhanced Brewer-Dobson circulation</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kracher, Daniela; Reick, Christian H.; Manzini, Elisa; Schultz, Martin G.; Stein, Olaf</p> <p>2016-06-01</p> <p>The Brewer-Dobson circulation (BDC), which is an important driver of the <span class="hlt">stratosphere</span>-troposphere exchange, is expected to accelerate with climate change. One particular consequence of this acceleration is the enhanced transport of nitrous oxide (N2O) from its sources at the Earth's surface toward its main sink region in the <span class="hlt">stratosphere</span>, thus inducing a reduction in its lifetime. N2O is a potent greenhouse gas and the most relevant currently emitted ozone-depleting substance. Here we examine the implications of a reduced N2O lifetime in the context of climate change. We find a decrease in its global <span class="hlt">warming</span> potential (GWP) and, due to a decline in the atmospheric N2O burden, also a reduction in its total radiative forcing. From the idealized transient global <span class="hlt">warming</span> simulation we can identify linear regressions for N2O sink, lifetime, and GWP with temperature rise. Our findings are thus not restricted to a particular scenario.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014E%26SS....1....1S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014E%26SS....1....1S"><span id="translatedtitle">Cloud formation, convection, and <span class="hlt">stratospheric</span> dehydration</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Schoeberl, Mark R.; Dessler, Andrew E.; Wang, Tao; Avery, Melody A.; Jensen, Eric J.</p> <p>2014-12-01</p> <p>Using the Modern-Era Retrospective Analysis for Research and Applications (MERRA) reanalysis winds, temperatures, and anvil cloud ice, we use our domain-filling, forward trajectory model combined with a new cloud module to show that convective transport of saturated air and ice to altitudes below the tropopause has a significant impact on <span class="hlt">stratospheric</span> water vapor and upper tropospheric clouds. We find that including cloud microphysical processes (rather than assuming that parcel water vapor never exceeds saturation) increases the lower <span class="hlt">stratospheric</span> average H2O by 10-20%. Our model-computed cloud fraction shows reasonably good agreement with tropical upper troposphere (TUT) cloud frequency observed by the Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) instrument in boreal winter with poorer agreement in summer. Our results suggest that over 40% of TUT cirrus is due to convection, and it is the saturated air from convection rather than injected cloud ice that primarily contributes to this increase. Convection can add up to 13% more water to the <span class="hlt">stratosphere</span>. With just convective hydration (convection adds vapor up to saturation), the global lower <span class="hlt">stratospheric</span> modeled water vapor is close to Microwave Limb Sounder observations. Adding convectively injected ice increases the modeled water vapor to ~8% over observations. Improving the representation of MERRA tropopause temperatures fields reduces <span class="hlt">stratospheric</span> water vapor by ~4%.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016EGUGA..1815194P&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016EGUGA..1815194P&link_type=ABSTRACT"><span id="translatedtitle">The fate of <span class="hlt">stratospheric</span> potential vorticity cutoffs</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Portmann, Raphael; Crezee, Bas; Quinting, Julian; Wernli, Heini</p> <p>2016-04-01</p> <p><span class="hlt">Stratospheric</span> cutoffs of potential vorticity (PV) frequently form through non-linear breaking of Rossby waves in mid-latitudes. Through destabilisation of the tropospheric layers beneath, they can trigger convection. Alternatively, through their induced horizontal advection they can produce intense precipitation events near topography and in regions with a background baroclinicity. PV cutoff lifecycles show high variability: their lifetime ranges between 1 and more than 10 days and the end of the lifecycle can occur through diabatic decay - leading to <span class="hlt">stratosphere</span>-troposphere exchange - or re-absorption by the polar <span class="hlt">stratospheric</span> reservoir. The relative frequency of these two processes is however unclear, as is the quantitative link between cutoffs and convective and large-scale precipitation. Two case studies are performed by using ECMWF analysis data, backward trajectories and radio soundings to look in detail at the processes involved in the diabatic decay. It is found that latent heating in convective updrafts - and the associated cross-isentropic transport of low PV air - largely explains the diabatic decay of the cutoffs. Using a tracking algorithm we produce an ERA-Interim cutoff climatology that provides information about the statistics of the cutoff lifetime and the relative frequency of <span class="hlt">stratospheric</span> re-absorption versus diabatic decay. In addition, we track atmospheric stability and total column water beneath the cutoffs in order to investigate why certain cutoffs decay faster than others. The results contribute to a better understanding of the lifecycle of PV cutoffs and a particular process of <span class="hlt">stratosphere</span>-troposphere exchange.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19770060210&hterms=Ammonium+sulfate&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3DAmmonium%2Bsulfate','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19770060210&hterms=Ammonium+sulfate&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3DAmmonium%2Bsulfate"><span id="translatedtitle">Microphysical processes affecting <span class="hlt">stratospheric</span> aerosol particles</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Hamill, P.; Toon, O. B.; Kiang, C. S.</p> <p>1977-01-01</p> <p>Physical processes which affect <span class="hlt">stratospheric</span> aerosol particles include nucleation, condensation, evaporation, coagulation and sedimentation. Quantitative studies of these mechanisms to determine if they can account for some of the observed properties of the aerosol are carried out. It is shown that the altitude range in which nucleation of sulfuric acid-water solution droplets can take place corresponds to that region of the <span class="hlt">stratosphere</span> where the aerosol is generally found. Since heterogeneous nucleation is the dominant nucleation mechanism, the <span class="hlt">stratospheric</span> solution droplets are mainly formed on particles which have been mixed up from the troposphere or injected into the <span class="hlt">stratosphere</span> by volcanoes or meteorites. Particle growth by heteromolecular condensation can account for the observed increase in mixing ratio of large particles in the <span class="hlt">stratosphere</span>. Coagulation is important in reducing the number of particles smaller than 0.05 micron radius. Growth by condensation, applied to the mixed nature of the particles, shows that available information is consistent with ammonium sulfate being formed by liquid phase chemical reactions in the aerosol particles. The upper altitude limit of the aerosol layer is probably due to the evaporation of sulfuric acid aerosol particles, while the lower limit is due to mixing across the tropopause.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li class="active"><span>20</span></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_20 --> <div id="page_21" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li class="active"><span>21</span></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="401"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19990010757&hterms=Bismuth&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3DBismuth','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19990010757&hterms=Bismuth&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3DBismuth"><span id="translatedtitle">Bismuth Oxide Nanoparticles in the <span class="hlt">Stratosphere</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Rietmeijer, Frans J. M.; Mackinnon, Ian D. R.</p> <p>1997-01-01</p> <p>Platey grains of cubic Bi2O3, alpha-Bi2O3, and Bi2O(2.75), nanograins were associated with chondritic porous interplanetary dust particles W7029C1, W7029E5, and 2011C2 that were collected in the <span class="hlt">stratosphere</span> at 17-19 km altitude. Similar Bi oxide nanograins were present in the upper <span class="hlt">stratosphere</span> during May 1985. These grains are linked to the plumes of several major volcanic eruptions during the early 1980s that injected material into the <span class="hlt">stratosphere</span>. The mass of sulfur from these eruptions is a proxy for the mass of <span class="hlt">stratospheric</span> Bi from which we derive the particle number densities (p/cu m) for "average Bi2O3 nanograins" due to this volcanic activity and those necessary to contaminate the extraterrestrial chondritic porous interplanetary dust particles via collisional sticking. The match between both values supports the idea that Bi2O3 nanograins of volcanic origin could contaminate interplanetary dust particles in the Earth's <span class="hlt">stratosphere</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19930013868','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19930013868"><span id="translatedtitle">The atmospheric effects of <span class="hlt">stratospheric</span> aircraft</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Stolarski, Richard S. (Editor); Wesoky, Howard L. (Editor)</p> <p>1993-01-01</p> <p>This document presents a second report from the Atmospheric Effects of <span class="hlt">Stratospheric</span> Aircraft (AESA) component of NASA's High-Speed Research Program (HSRP). This document presents a second report from the Atmospheric Effects of <span class="hlt">Stratospheric</span> Aircraft (AESA) component of NASA's High Speed Research Program (HSRP). Market and technology considerations continue to provide an impetus for high-speed civil transport research. A recent United Nations Environment Program scientific assessment has shown that considerable uncertainty still exists about the possible impact of aircraft on the atmosphere. The AESA was designed to develop the body of scientific knowledge necessary for the evaluation of the impact of <span class="hlt">stratospheric</span> aircraft on the atmosphere. The first Program report presented the basic objectives and plans for AESA. This second report presents the status of the ongoing research as reported by the principal investigators at the second annual AESA Program meeting in May 1992: Laboratory studies are probing the mechanism responsible for many of the heterogeneous reactions that occur on <span class="hlt">stratospheric</span> particles. Understanding how the atmosphere redistributes aircraft exhaust is critical to our knowing where the perturbed air will go and for how long it will remain in the <span class="hlt">stratosphere</span>. The assessment of fleet effects is dependent on the ability to develop scenarios which correctly simulate fleet operations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19990026876','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19990026876"><span id="translatedtitle">Tropospheric- <span class="hlt">Stratospheric</span> Measurement Studies Summary</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Browen, Stuart W.</p> <p>1998-01-01</p> <p>The two high altitude aircraft, ER-2 NASA #706 and 709 and the DC-8 NASA #717 are in active use in several programs of upper atmospheric research to study polar ozone changes, <span class="hlt">stratospheric</span>-tropospheric exchange processes and atmospheric effects of aviation aircraft. The ER-2 has participated in seven major missions which mainly concentrated on vortex dynamics and the large losses of Ozone in the Polar regions (Ozone hole) observed in the spring. One mission verified the complex dynamical chemical and physical processes that occur during sunrise and sunset. <span class="hlt">Stratospheric</span> Tracers of Atmospheric Transport (STRAT) obtained background measurements using the full ER-2 suite of instruments. Photochemistry of Ozone Loss in the Arctic Region in Summer (POLARIS) in 1997 assisted in understanding the mid-latitude and Arctic Ozone losses during the Northern Summer. The DC-8 with the Meteorological Measurement System (MMS) has participated in the Subsonic Aircraft: Cloud and Contrail Effects Special Study (SUCCESS), in 1996 and the Subsonic assessment Ozone and Nitrogen oxide experiment (SONEX) in 1997 missions. The MMS with its sophisticated software accurately measures ground speed and attitude, in-situ static and dynamic pressure total temperature, which are used to calculate the three dimensional wind fields, static pressure, temperature and turbulence values to meteorological accuracy. The meteorological data is not only of interest for its own sake in atmospheric dynamical processes such as mountain waves and flux measurements; but is also required by other ER-2 experiments that simultaneously measure water vapor, O3, aerosols, NO, HCl, CH4, N2O, ClO, BrO, CO2, NOy, HOx and temperature gradients. MMS products are extensively used to assist in the interpretation of their results in understanding the importance of convective effects relative to in-situ chemical changes, as may be noted by examining the list of references attached. The MMS consists of three subsystems: (a</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19890020521','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19890020521"><span id="translatedtitle">Large-scale dynamics of the <span class="hlt">stratosphere</span> and mesosphere during the MAP/WINE campaign winter 1983 to 1984 in comparison with other winters</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Petzoldt, K.</p> <p>1989-01-01</p> <p>For the MAP/WINE winter temperature and wind measurements of rockets were combined with SSU radiances (<span class="hlt">Stratospheric</span> Sounder Unit onboard the NOAA satellites) and stratopause heights from the Solar Mesosphere Explorer (SME) to get a retrieved data set including all available information. By means of this data set a hemispheric geopotential height, temperature and geostrophic wind fields eddy transports for wave mean flow interaction and potential vorticity for the interpretation of nonlinear wave breaking could be computed. Wave reflection at critical lines was investigated with respect of <span class="hlt">stratospheric</span> <span class="hlt">warmings</span>. The meridional gradient of the potential vorticity and focusing of wave activity is compared with derived data from satellite observations during other winters.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19890001411','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19890001411"><span id="translatedtitle">Numerical simulations of dust transport into northern high latitudes during a Martian polar <span class="hlt">warming</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Barnes, J. R.; Hollingsworth, J. L.</p> <p>1987-01-01</p> <p>The formation and evolution of the polar laminated terrain depends on rates of dust transport to the polar caps. A simplified dynamical model is shown similar to models used to simulate terrestrial <span class="hlt">stratospheric</span> polar <span class="hlt">warmings</span> could simulate certain observed features of the circulation during Martian global dust storms. Model simulations of dust transport showed that substantial quantities of dust, enough to produce optical depths of approx. 1, could reach the pole during these storms.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2006epsc.conf..426C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2006epsc.conf..426C"><span id="translatedtitle">Nitrogen compounds in Titan's <span class="hlt">stratosphere</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Coustenis, A.; Cirs Investigation Team</p> <p></p> <p>Titan's atmosphere is essentially composed of molecular nitrogen (N2). The chemistry between the two mother molecules (N2 and CH4) leads to the formation of a certain number of nitriles observed in Titan's <span class="hlt">stratosphere</span> as early as at the time of the Voyager 1 encounter in 1980. In the spectra taken by the Infrared Radiometer Interferometer Spectrometer (IRIS) the signatures of HCN, HC3N, C2N2 and C4N2 (in solid form) were found and reported. Subsequent observations from the ground better described the vertical profiles of these constituents and allowed for the detection of CH3CN (acetonitrile) in the mm range [3,4]. Recent data recorded by the Composite Infrared Spectrometer (CIRS) aboard the Cassini spacecraft during the Titan flybys (October 2004 - June 2006) give a handle on the temporal and latitudinal variations of these constituents. The nadir spectra characterize various regions on Titan from 85°S to 75°N with a variety of emission angles. We study the emission observed in the mid-infrared CIRS detector arrays (covering roughly the 600-1500 cm-1 spectral range with apodized resolutions of 2.54 or 0.53 cm-1 ). The composite spectrum shows several molecular signatures of nitriles. Information is retrieved on the meridional variations of the trace constituents and tied to predictions by dynamical-photochemical models [1,2,5]. The nitriles show a significant enhancement at high northern latitudes albeit not as marked as at the time of the Voyager encounter. We will give a review of our current understanding of the minor nitrile chemistry on Titan. References : [1] Coustenis et al., 2006. Icarus, in press. [2] Flasar et al., 2005. Science 308, 975. [3] Marten, A., et al., 2002, Icarus, 158, 532-544. [4] Marten, A. & Moreno, R., 2003. 35th Annual DPS Meeting, Monterey, Ca, BAAS, 35, 952. [5] Teanby et al., 2006. Icarus, 181, 243-255.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014ACPD...1418049K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014ACPD...1418049K"><span id="translatedtitle">The impact of polar <span class="hlt">stratospheric</span> ozone loss on Southern Hemisphere <span class="hlt">stratospheric</span> circulation and climate</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Keeble, J.; Braesicke, P.; Abraham, N. L.; Roscoe, H. K.; Pyle, J. A.</p> <p>2014-07-01</p> <p>The impact of polar <span class="hlt">stratospheric</span> ozone loss resulting from chlorine activation on polar <span class="hlt">stratospheric</span> clouds is examined using a pair of model integrations run with the fully coupled chemistry climate model UM-UKCA. Suppressing chlorine activation through heterogeneous reactions is found to produce modelled ozone differences consistent with observed ozone differences between the present and pre-ozone hole period. Statistically significant high latitude Southern Hemisphere (SH) ozone loss begins in August and peaks in October-November, with >75% of ozone destroyed at 50 hPa. Associated with this ozone destruction is a >12 K decrease of the lower polar <span class="hlt">stratospheric</span> temperatures and an increase of >6 K in the upper <span class="hlt">stratosphere</span>. The heating components of this temperature change are diagnosed and it is found that the temperature dipole is the result of decreased shortwave heating in the lower <span class="hlt">stratosphere</span> and increased dynamical heating in the upper <span class="hlt">stratosphere</span>. The cooling of the polar lower <span class="hlt">stratosphere</span> leads, through thermal wind balance, to an acceleration of the polar vortex and delays its breakdown by ~2 weeks. A link between lower <span class="hlt">stratospheric</span> zonal wind speed, the vertical component of the EP flux, Fz, and the residual mean vertical circulation, <span style="text-decoration: overline">w*, is identified. In December and January, increased westerly winds lead to increases in Fz, associated with an increase in tropopause height. The resulting increase in wavebreaking leads to enhanced downwelling/reduced upwelling over the polar cap. Many of the <span class="hlt">stratospheric</span> signals modelled in this study propagate down to the troposphere, and lead to significant surface changes in December.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19850042627&hterms=SAMs+mexico&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3DSAMs%2Bmexico','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19850042627&hterms=SAMs+mexico&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3DSAMs%2Bmexico"><span id="translatedtitle">Surface sulfur measurements on <span class="hlt">stratospheric</span> particles</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Mackinnon, I. D. R.; Mogk, D. W.</p> <p>1985-01-01</p> <p>The surface chemistries of three particulate samples collected from the lower <span class="hlt">stratosphere</span> have been determined using a Scanning Auger Microprobe (SAM). These samples are typical of the most abundant natural and anthropogenic particles observed within the <span class="hlt">stratosphere</span> in the greater-than-2-micron diameter size fraction. Succsessive sputtering and analysis below the first few adsorbed monolayers of all particles shows the presence of a thin (less than 150A) sulfur layer. These sulfur regions probably formed by surface reaction of sulfur-rich aerosols with each particle within the <span class="hlt">stratosphere</span>. Settling rate calculations show that a typical sphere (10-micron diameter) may reside within the aerosol layer for 20 days and thus provide a qualitative guide to surface sulfur reaction rates.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19920009885','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19920009885"><span id="translatedtitle">Lower <span class="hlt">Stratospheric</span> Measurement Issues Workshop Report</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Schmeltekopf, Arthur L.</p> <p>1992-01-01</p> <p>The Lower <span class="hlt">Stratospheric</span> Measurement Issues workshop was held on 17-19 Oct. 1990. The 3-day workshop was sponsored by the Atmospheric Effects of <span class="hlt">Stratospheric</span> Aircraft (AESA) component of the High Speed Research Program (HSRP). Its purpose was to provide a scientific forum for addressing specific issues regarding chemistry and transport in the lower <span class="hlt">stratosphere</span>, for which measurements are essential to an assessment of the environmental impact of a projected fleet of high speed civil transports (HSCTs). The objective of the workshop was to obtain vigorous and critical review of the following topics: (1) atmospheric measurements needed for the assessment; (2) present capability for making those measurements; and (3) areas in instrumentation or platform development essential to making the measurements.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19950043435&hterms=marx&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dmarx','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19950043435&hterms=marx&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dmarx"><span id="translatedtitle">Observations of lightning in the <span class="hlt">stratosphere</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Boeck, William L.; Vaughan, Otha H., Jr.; Blakeslee, Richard J.; Vonnegut, Bernard; Brook, Marx; Mckune, John</p> <p>1995-01-01</p> <p>An examination and analysis of video images of lightning, captured by the payload bay TV cameras of the space shuttle, provided a variety of examples of lightning in the <span class="hlt">stratosphere</span> above thunderstorms. These images were obtained on several recent shuttle flights while conducting the Mesoscale Lightning Experiment (MLE). The images of <span class="hlt">stratospheric</span> lightning illustrate the variety of filamentary and broad vertical discharges in the <span class="hlt">stratosphere</span> that may accompany a lightning flash. A typical event is imaged as a single or multiple filament extending 30 to 40 km above a thunderstorm that is illuminated by a series of lightning strokes. Examples are found in temperate and tropical areas, over the oceans, and over the land.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19900012594&hterms=features+granted+past+now&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dfeatures%2Bgranted%2Bpast%2Bnow','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19900012594&hterms=features+granted+past+now&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dfeatures%2Bgranted%2Bpast%2Bnow"><span id="translatedtitle">New spectral features of <span class="hlt">stratospheric</span> trace gases</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Goldman, A.; Murcray, F. J.; Blatherwick, R. D.; Kosters, J. J.; Murcray, F. H.; Murcray, D. G.; Rinsland, C. P.</p> <p>1990-01-01</p> <p>A new Michelson-type interferometer system operating in the infrared at very high resolution (0.002 to 0.003 wavenumber FWHM) was used to record numerous balloon-borne solar absorption spectra of the <span class="hlt">stratosphere</span>, ground-based solar absorption spectra, and laboratory spectra of molecules of atmospheric interest. Results obtained are reported for several important <span class="hlt">stratospheric</span> trace gases, HNO3, ClONO2, HO2NO2, NO2, and COF2, in the 8 to 12 micron spectral region. Many features of these gases were identified in the <span class="hlt">stratospheric</span> spectra. Comparison of the spectra with line-by-line simulations shows previous spectral parameters are often inadequate. New analysis of high resolution laboratory and atmospheric spectra and improved theoretical calculations will be required for all bands. Preliminary versions of several sets of improved line parameters are presented.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2011JCos...16.6677B&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2011JCos...16.6677B&link_type=ABSTRACT"><span id="translatedtitle">Sources of particulates in the upper <span class="hlt">stratosphere</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bigg, E. Keith</p> <p>2011-10-01</p> <p>The dominant forms of particles collected at altitudes of 39, 42 and 45km during three balloon flights over Australia were aggregates having components with diameters typically 40 to 50nm. Their partial electron transparency suggested an organic composition and all were accompanied by a volatile liquid that could be stabilised by reaction with a thin copper film. They closely resembled particles called "fluffy micrometeorites" collected earlier in the mesosphere from rockets and their properties were consistent with those of particles collected from a comet by a recent spacecraft experiment. Particles in the upper <span class="hlt">stratosphere</span> included some that resembled viruses and cocci, the latter being one of the organisms cultured from upper <span class="hlt">stratospheric</span> air in a recent experiment. A plausible source of the <span class="hlt">stratospheric</span>, mesospheric and cometary aggregates is consistent with the "panspermia" theory, that microorganisms present in space at the birth of the solar system could have reproduced in water within comets and brought life to Earth.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2002AGUSM.B22D..07B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2002AGUSM.B22D..07B"><span id="translatedtitle">Photolytic Fractionation of <span class="hlt">Stratospheric</span> Nitrous Oxide</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Blake, G. A.; Liang, M.; Morgan, C. G.</p> <p>2002-05-01</p> <p>The isotopically light N2O produced by microbial activity is known to be balanced by the return of heavy <span class="hlt">stratospheric</span> nitrous oxide. Present atmospheric models predict fractionation factors approximately half those observed, however, leaving open the possibility that unknown processes generate substantial quantities of isotopically enriched nitrous oxide. Here we present a rigorous Born-Oppenheimer analysis of the wavelength-dependent N2O photolytic fractionation and incorporate the resulting fractionation factors into two-dimensional simulations of the <span class="hlt">stratosphere</span>. Excellent agreement is found between predictions and laboratory/<span class="hlt">stratospheric</span> measurements, and implies that our understanding of the photochemical cycling of this important trace gas is sufficiently complete to permit quantitative determinations of the natural and anthropogenic sources of N2O using their isotopic signatures.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20060033954&hterms=Chlorine&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3DChlorine','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20060033954&hterms=Chlorine&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3DChlorine"><span id="translatedtitle">Measurements of Chlorine Partitioning in the Winter Arctic <span class="hlt">Stratosphere</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Stachnik, R.; Salawitch, R.; Engel, A.; Schmidt, U.</p> <p>1999-01-01</p> <p>Under the extremely cold conditions in the polar winter <span class="hlt">stratosphere</span>, heterogeneous reactions involving HCl and CIONO(sub 2) on the surfaces of polar <span class="hlt">stratospheric</span> cloud particles can release large amounts of reactive chlorine from these reservoirs leading to rapid chemical loss of ozone in the Arctic lower <span class="hlt">stratosphere</span> during late winter and early spring.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2005AGUFM.A23B0953T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2005AGUFM.A23B0953T"><span id="translatedtitle">The Truth about <span class="hlt">Stratospheric</span> Aerosols: Key Results from SPARC`s Assessment of <span class="hlt">Stratospheric</span> Aerosol Properties</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Thomason, L. W.; Peter, T.</p> <p>2005-12-01</p> <p>Given the critical role it plays in ozone chemistry, the Assessment of <span class="hlt">Stratospheric</span> Aerosol Properties (ASAP) has been carried out by the WCRP project on <span class="hlt">Stratospheric</span> Process and their Role in Climate (SPARC). The objective of this report was to present a systematic analysis of the state of knowledge of <span class="hlt">stratospheric</span> aerosols including their precursors. It includes an examination of precursor concentrations and trends, measurements of <span class="hlt">stratospheric</span> aerosol properties, trends in those properties, and modeling their formation, transport, and distribution in both background and volcanic conditions. The assessment found that the dominant nonvolcanic <span class="hlt">stratospheric</span> aerosol precursor gases are OCS, SO2, and tropospheric aerosol. Therefore, though SO2, human-related activities play a significant role in the observed background <span class="hlt">stratospheric</span> aerosol. There is general agreement between measured OCS and modeling of its transformation to sulfate aerosol, and observed aerosols. However, there is a significant dearth of SO2 measurements, and the role of tropospheric SO2 in the <span class="hlt">stratospheric</span> aerosol budget - while significant - remains a matter of some guesswork. The assessment also found that there is basic agreement between the various data sets and models particularly during periods of elevated loading. However, at background levels significant differences were found that indicate that substantial questions remain regarding the nature of <span class="hlt">stratospheric</span> aerosol during these periods particularly in the lower <span class="hlt">stratosphere</span>. For instance, during periods of very low aerosol loading significant differences exist between systems for key parameters including aerosol surface area density and extinction. At the same time, comparisons of models and satellite observations of aerosol extinction found good agreement at visible wavelengths above 20-25 km altitude region but are less satisfactory for infrared wavelengths. While there are some model short-comings relative to observations in</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19890016421','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19890016421"><span id="translatedtitle">Transport of Mars atmospheric water into high northern latitudes during a polar <span class="hlt">warming</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Barnes, J. R.; Hollingsworth, J. L.</p> <p>1988-01-01</p> <p>Several numerical experiments were conducted with a simplified tracer transport model in order to attempt to examine the poleward transport of Mars atmospheric water during a polar <span class="hlt">warming</span> like that which occurred during the winter solstice dust storm of 1977. The flow for the transport experiments was taken from numerical simulations with a nonlinear beta-plane dynamical model. Previous studies with this model have demonstrated that a polar <span class="hlt">warming</span> having essential characteristics like those observed during the 1977 dust storm can be produced by a planetary wave mechanism analogous to that responsible for terrestrial sudden <span class="hlt">stratospheric</span> <span class="hlt">warmings</span>. Several numerical experiments intended to simulate water transport in the absence of any condensation were carried out. These experiments indicate that the flow during a polar <span class="hlt">warming</span> can transport very substantial amounts of water to high northern latitudes, given that the water does not condense and fall out before reaching the polar region.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20030064053&hterms=nsf&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3Dnsf','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20030064053&hterms=nsf&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3Dnsf"><span id="translatedtitle">Large-scale <span class="hlt">Stratospheric</span> Transport Processes</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Plumb, R. Alan</p> <p>2003-01-01</p> <p>The PI has undertaken a theoretical analysis of the existence and nature of compact tracer-tracer relationships of the kind observed in the <span class="hlt">stratosphere</span>, augmented with three-dimensional model simulations of <span class="hlt">stratospheric</span> tracers (the latter being an extension of modeling work the group did during the SOLVE experiment). This work achieves a rigorous theoretical basis for the existence and shape of these relationships, as well as a quantitative theory of their width and evolution, in terms of the joint tracer-tracer PDF distribution. A paper on this work is almost complete and will soon be submitted to Rev. Geophys. We have analyzed lower <span class="hlt">stratospheric</span> water in simulations with an isentropic-coordinate version of the MATCH transport model which we recently helped to develop. The three-dimensional structure of lower <span class="hlt">stratospheric</span> water, in particular, attracted our attention: dry air is, below about 400K potential temperature, localized in the regions of the west Pacific and equatorial South America. We have been analyzing air trajectories to determine how air passes through the tropopause cold trap. This work is now being completed, and a paper will be submitted to Geophys. Res. Lett. before the end of summer. We are continuing to perform experiments with the 'MATCH' CTM, in both sigma- and entropy-coordinate forms. We earlier found (in collaboration with Dr Natalie Mahowald, and as part of an NSF-funded project) that switching to isentropic coordinates made a substantial improvement to the simulation of the age of <span class="hlt">stratospheric</span> air. We are now running experiments with near-tropopause sources in both versions of the model, to see if and to what extent the simulation of <span class="hlt">stratosphere</span>-troposphere transport is dependent on the model coordinate. Personnel Research is supervised by the PI, Prof. Alan Plumb. Mr William Heres conducts the tracer modeling work and performs other modeling tasks. Two graduate students, Ms Irene Lee and Mr Michael Ring, have been participating</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014EGUGA..1612671M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014EGUGA..1612671M"><span id="translatedtitle">Is <span class="hlt">stratospheric</span> air getting younger with time?</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Monge-Sanz, Beatriz; Chipperfield, Martyn; Dee, Dick; Simmons, Adrian; Stiller, Gabriele</p> <p>2014-05-01</p> <p>Most climate models have predicted that with the increase in greenhouse gases concentrations, the <span class="hlt">stratospheric</span> circulation will intensify, showing younger age-of-air (AoA) values in this region (e.g. Butchart et al., 2010; WMO, 2011). However, balloon and satellite observations do not agree with the widespread modelled trend towards younger age-of-air (Engel et al., 2009; Stiller et al., 2012). To increase our confidence in climate-chemistry projections, the causes for the apparent age-of-air disagreement between observations and most models need to be identified. Here we have carried out <span class="hlt">stratospheric</span> simulations with a chemistry transport model (CTM) to evaluate the <span class="hlt">stratospheric</span> circulation with the ERA-Interim dataset produced by the European Centre for Medium-Range Weather Forecasts (ECMWF). The ERA-Interim reanalysis provides age-of-air (AoA) distributions in very good agreement with observations in the lower <span class="hlt">stratosphere</span>. Given this agreement, we have used our simulations to quantify interannual variability and trends in the <span class="hlt">stratospheric</span> AoA for the whole ERA-Interim period (1979-present). Our model results with ERA-Interim fields disagree with the decreasing tendency in age-of-air widespread in most models, but are in good agreement with the recent age-of-air studies based on observations. To explore potential causes for the AoA trends in our model, Lagrangian calculations are also performed to assess mixing processes for the ERA-Interim period. Potential links between our modelled AoA trends and <span class="hlt">stratospheric</span> ozone evolution are also shown. References: Butchart, et al., 2010. J. Climate, 23, 5349-5374, doi:10.1175/2010JCLI3404.1. Engel et al., 2009. Nat. Geosci. 2: 28-31, doi:10.1038/ngeo388. Stiller et al., 2012. Atmos. Chem. Phys. 12: 3311-3331, doi:10.5194/acp-12-3311-2012. WMO. 2011. Global Ozone Research and Monitoring Project -Report No. 52.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19990097312&hterms=Information+Retrieval&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3DInformation%2BRetrieval','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19990097312&hterms=Information+Retrieval&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3DInformation%2BRetrieval"><span id="translatedtitle">Improved <span class="hlt">Stratospheric</span> Temperature Retrievals for Climate Reanalysis</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Rokke, L.; Joiner, J.</p> <p>1999-01-01</p> <p>The Data Assimilation Office (DAO) is embarking on plans to generate a twenty year reanalysis data set of climatic atmospheric variables. One of the focus points will be in the evaluation of the dynamics of the <span class="hlt">stratosphere</span>. The <span class="hlt">Stratospheric</span> Sounding Unit (SSU), flown as part of the TIROS Operational Vertical Sounder (TOVS), is one of the primary <span class="hlt">stratospheric</span> temperature sensors flown consistently throughout the reanalysis period. Seven unique sensors made the measurements over time, with individual instrument characteristics that need to be addressed. The <span class="hlt">stratospheric</span> temperatures being assimilated across satellite platforms will profoundly impact the reanalysis dynamical fields. To attempt to quantify aspects of instrument and retrieval bias we are carefully collecting and analyzing all available information on the sensors, their instrument anomalies, forward model errors and retrieval biases. For the retrieval of <span class="hlt">stratospheric</span> temperatures, we adapted the minimum variance approach of Jazwinski (1970) and Rodgers (1976) and applied it to the SSU soundings. In our algorithm, the state vector contains an initial guess of temperature from a model six hour forecast provided by the Goddard EOS Data Assimilation System (GEOS/DAS). This is combined with an a priori covariance matrix, a forward model parameterization, and specifications of instrument noise characteristics. A quasi-Newtonian iteration is used to obtain convergence of the retrieved state to the measurement vector. This algorithm also enables us to analyze and address the systematic errors associated with the unique characteristics of the cell pressures on the individual SSU instruments and the resolving power of the instruments to vertical gradients in the <span class="hlt">stratosphere</span>. The preliminary results of the improved retrievals and their assimilation as well as baseline calculations of bias and rms error between the NESDIS operational product and col-located ground measurements will be presented.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012GeoRL..39.2806Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012GeoRL..39.2806Z"><span id="translatedtitle">Importance of the upper-level <span class="hlt">warm</span> core in the rapid intensification of a tropical cyclone</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zhang, Da-Lin; Chen, Hua</p> <p>2012-01-01</p> <p>In this study, the rapid intensification (RI) of tropical cyclone is examined using a 72-h cloud-permitting prediction of Hurricane Wilma (2005) with a record-breaking intensity of 882 hPa. Results show the formation of an upper-level <span class="hlt">warm</span> core from the descending air of <span class="hlt">stratospheric</span> origin in the eye, which coincides with the onset of RI; it reaches the peak amplitude of more than 18°C from its initial conditions at the time of peak intensity. The descending air is associated with the detrainment of convective bursts in the eyewall, and it appears as (perturbation) cyclonic radial inflows above the upper outflow layer and causes the subsidence <span class="hlt">warming</span> below. We hypothesize that the upper divergent outflow layer favors the generation of a <span class="hlt">warm</span> core by protecting it from ventilation by environmental flows. Use of the hydrostatic equation shows that the <span class="hlt">warm</span> core of <span class="hlt">stratospheric</span> origin contributes more than twice as much as the lower-level <span class="hlt">warm</span> column to the pressure change at the peak intensity of Wilma. Results suggest that more attention be paid to the magnitude of storm-relative flows and vertical wind shear in the upper troposphere, rather than just vertical shear in the typical 850-200 hPa layer, in order to reasonably predict the RI of tropical cyclones.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li class="active"><span>21</span></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_21 --> <div id="page_22" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li class="active"><span>22</span></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="421"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/121740','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/121740"><span id="translatedtitle">Modeling the effects of UV variability and the QBO on the troposphere-<span class="hlt">stratosphere</span> system. Part II: The troposphere</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Rind, D.; Balachandran, N.K.</p> <p>1995-08-01</p> <p>Results of experiments with a GCM involving changes in UV input ({plus_minus} 25%, {plus_minus}5% at wavelengths below 0.3 {mu}) and simulated equatorial QBO are presented, with emphasis on the tropospheric response. The QBO and UV changes alter the temperature in the lower <span class="hlt">stratosphere</span>/upper troposphere <span class="hlt">warms</span>, tropospheric eddy energy is reduced, leading to extratropical tropospheric cooling of some 0.5{degrees}C on the zonal average, and surface temperature changes up to {plus_minus}5{degrees}C locally. Opposite effects occur when the extratropical lower <span class="hlt">stratosphere</span>/upper troposphere cools. Cooling or <span class="hlt">warming</span> of the comparable region in the Tropics decreases/increases static stability, accelerating/decelerating the Hadley circulation. Tropospheric dynamical changes are on the order of 5%. The combined UV/QBO effect in the troposphere results from its impact on the middle atmosphere; in the QBO east phase, more energy is refracted to higher latitudes, due to the increased horizontal shear of the zonal wind, but with increased UV, this energy propagates preferentially out of the polar lower <span class="hlt">stratosphere</span>, in response to the increased vertical shear of the zonal winds; therefore, it is less effective in <span class="hlt">warming</span> the polar lower <span class="hlt">stratosphere</span>. Due to their impacts on planetary wave generation and propagation, all combinations of UV and QBO phases affect the longitudinal patterns of tropospheric temperatures and geopotential heights. The modeled perturbations often agree qualitatively with observations and are of generally similar orders of magnitude. The results are sensitive to the forcing employed. In particular, the nature of the tropospheric response depends upon the magnitude (and presumably wavelength) of the solar irradiance perturbation. The results of the smaller UV variations ({plus_minus}5%) are more in agreement with observations, showing clear differences between the UV impact in the east and west QBO phase. 34 refs., 15 figs., 3 tabs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/164894','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/164894"><span id="translatedtitle">Y-12 Plant <span class="hlt">Stratospheric</span> Ozone Protection plan</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p></p> <p>1995-09-01</p> <p>The Y-12 Plant staff is required by Lockheed Martin Energy Systems (Energy Systems) (formerly Martin Marietta Energy Systems) standard ESS-EP-129 to develop and implement a <span class="hlt">Stratospheric</span> Ozone Protection Program which will minimize emissions of ozone-depleting substances to the environment and maximize the use of ozone-safe alternatives in order to comply with Title VI of the 1990 Clean Air Act (CAA) Amendments and the implementing regulations promulgated by the Environmental Protection Agency (EPA). This plan describes the requirements, initiatives, and accomplishments of the Y-12 Plant <span class="hlt">Stratospheric</span> Ozone Protection Program.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19840018305','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19840018305"><span id="translatedtitle">Advanced laser <span class="hlt">stratospheric</span> monitoring systems analyses</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Larsen, J. C.</p> <p>1984-01-01</p> <p>This report describes the software support supplied by Systems and Applied Sciences Corporation for the study of Advanced Laser <span class="hlt">Stratospheric</span> Monitoring Systems Analyses under contract No. NAS1-15806. This report discusses improvements to the Langley spectroscopic data base, development of LHS instrument control software and data analyses and validation software. The effect of diurnal variations on the retrieved concentrations of NO, NO2 and C L O from a space and balloon borne measurement platform are discussed along with the selection of optimum IF channels for sensing <span class="hlt">stratospheric</span> species from space.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19900041437&hterms=hydrochloric+acid&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dhydrochloric%2Bacid','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19900041437&hterms=hydrochloric+acid&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dhydrochloric%2Bacid"><span id="translatedtitle">Incorporation of <span class="hlt">stratospheric</span> acids into water ice</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Elliott, Scott; Turco, Richard P.; Toon, Owen B.; Hamill, Patrick</p> <p>1990-01-01</p> <p>Hydrochloric and hydrofluoric acids are absorbed within the water ice lattice at mole fractions maximizing below 0.00001 and 0.0001 in a variety of solid impurity studies. The absorption mechanism may be substitutional or interstitial, leading in either case to a weak permeation of <span class="hlt">stratospheric</span> ices by the acids at equilibrium. Impurities could also inhabit grain boundaries, and the acid content of atmospheric ice crystals will then depend on details of their surface and internal microstructures. Limited evidence indicates similar properties for the absorption of HNO3. Water ice lattices saturated with acid cannot be a significant local reservoir for HCl in the polar <span class="hlt">stratosphere</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19790034308&hterms=Ozone+layer&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3D%2528Ozone%2Blayer%2529','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19790034308&hterms=Ozone+layer&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3D%2528Ozone%2Blayer%2529"><span id="translatedtitle">SSTs, nitrogen fertiliser and <span class="hlt">stratospheric</span> ozone</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Turco, R. P.; Whitten, R. C.; Poppoff, I. G.; Capone, L. A.</p> <p>1978-01-01</p> <p>A recently revised model of the <span class="hlt">stratosphere</span> is used to show that a substantial enhancement in the ozone layer could accompany worldwide SST fleet operations and that water vapor may be an important factor in SST assessments. Revised rate coefficients for various ozone-destroying reactions are employed in calculations which indicate a slight increase in the total content of <span class="hlt">stratospheric</span> ozone for modest-sized fleets of SSTs flying below about 25 km. It is found that water-vapor chemical reactions can negate in large part the NOx-induced ozone gains computed below 25 km and that increased use of nitrogen fertilizer might also enhance the ozone layer.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19920033133&hterms=Uranus&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3DUranus','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19920033133&hterms=Uranus&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3DUranus"><span id="translatedtitle">Equatorial waves in the <span class="hlt">stratosphere</span> of Uranus</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Hinson, David P.; Magalhaes, Julio A.</p> <p>1991-01-01</p> <p>Analyses of radio occultation data from Voyager 2 have led to the discovery and characterization of an equatorial wave in the Uranus <span class="hlt">stratosphere</span>. The observed quasi-periodic vertical atmospheric density variations are in close agreement with theoretical predictions for a wave that propagates vertically through the observed background structure of the <span class="hlt">stratosphere</span>. Quantitative comparisons between measurements obtained at immersion and at emersion yielded constraints on the meridional and zonal structure of the wave; the fact that the two sets of measurements are correlated suggests a wave of planetary scale. Two equatorial wave models are proposed for the wave.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20070034037&hterms=Hydrocyanic+acid&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3D%2528Hydrocyanic%2Bacid%2529','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20070034037&hterms=Hydrocyanic+acid&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3D%2528Hydrocyanic%2Bacid%2529"><span id="translatedtitle">On the <span class="hlt">Stratospheric</span> Chemistry of Hydrogen Cyanide</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Kleinbohl, Armin; Toon, Geoffrey C.; Sen, Bhaswar; Blavier, Jean-Francois L.; Weisenstein, Debra K.; Strekowski, Rafal S.; Nicovich, J. Michael; Wine, Paul H.; Wennberg, Paul O.</p> <p>2006-01-01</p> <p>HCN profiles measured by solar occultation spectrometry during 10 balloon flights of the JPL MkIV instrument are presented. The HCN profiles reveal a compact correlation with <span class="hlt">stratospheric</span> tracers. Calculations with a 2D-model using established rate coefficients for the reactions of HCN with OH and O(1D) severely underestimate the measured HCN in the middle and upper <span class="hlt">stratosphere</span>. The use of newly available rate coefficients for these reactions gives reasonable agreement of measured and modeled HCN. An HCN yield of approx.30% from the reaction of CH3CN with OH is consistent with the measurements.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19910050225&hterms=Jay+Martin&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAuthor-Name%26N%3D0%26No%3D10%26Ntt%3DJay%2BMartin','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19910050225&hterms=Jay+Martin&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAuthor-Name%26N%3D0%26No%3D10%26Ntt%3DJay%2BMartin"><span id="translatedtitle">Thermal maps of Jupiter - Spatial organization and time dependence of <span class="hlt">stratospheric</span> temperatures, 1980 to 1990</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Orton, Glenn S.; Friedson, A. James; Baines, Kevin H.; Martin, Terry Z.; West, Robert A.; Caldwell, John; Hammel, Heidi B.; Bergstralh, Jay T.; Malcolm, Michael E.</p> <p>1991-01-01</p> <p>The spatial organization and time dependence of Jupiter's <span class="hlt">stratospheric</span> temperatures have been measured by observing thermal emission from the 7.8-micrometer CH4 band. These temperatures, observed through the greater part of a Jovian year, exhibit the influence of seasonal radiative forcing. Distinct bands of high temperature are located at the poles and midlatitudes, while the equator alternates between <span class="hlt">warm</span> and cold with a period of approximately 4 years. Substantial longitudinal variability is often observed within the <span class="hlt">warm</span> midlatitude bands, and occasionally elsewhere on the planet. This variability includes small, localized structures, as well as large-scale waves with wavelengths longer than about 30,000 kilometers. The amplitudes of the waves vary on a time scale of about 1 month; structures on a smaller scale may have lifetimes of only days. Waves observed in 1985, 1987, and 1988 propagated with group velocities less than + or - 30 meters/sec.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://eric.ed.gov/?q=bridges+AND+type&pg=5&id=EJ1002704','ERIC'); return false;" href="http://eric.ed.gov/?q=bridges+AND+type&pg=5&id=EJ1002704"><span id="translatedtitle"><span class="hlt">Warm</span> and Cool Cityscapes</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Jubelirer, Shelly</p> <p>2012-01-01</p> <p>Painting cityscapes is a great way to teach first-grade students about <span class="hlt">warm</span> and cool colors. Before the painting begins, the author and her class have an in-depth discussion about big cities and what types of buildings or structures that might be seen in them. They talk about large apartment and condo buildings, skyscrapers, art museums,…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20020041061&hterms=hydrates&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Dhydrates','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20020041061&hterms=hydrates&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Dhydrates"><span id="translatedtitle">Investigating Type I Polar <span class="hlt">Stratospheric</span> Cloud Formation Mechanisms with POAM Satellite Observations</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Strawa, Anthony W.; Drdla, K.; Fromm, M.; Hoppel, K.; Browell, E.; Hamill, P.; Dempsey, D.; Gore, Warren J. (Technical Monitor)</p> <p>2001-01-01</p> <p>Type Ia PSCs are believed to be composed of nitric acid hydrate particles. Recent results from the SOLVE/THESEO 2000 campaign showed evidence that this type of PSC was composed of a small number of very large particles capable of sedimentary denitrification of regions of the <span class="hlt">stratosphere</span>. It is unknown whether homogeneous or heterogeneous nucleation is responsible for the formation of these PSCs. Arctic winters are tending to be colder in response to global tropospheric <span class="hlt">warming</span>. The degree to which this influences ozone depletion will depend on the freezing mechanism of nitric acid hydrate particles. If nucleation is homogeneous it implies that the freezing process is an inherent property of the particle, while heterogeneous freezing means that the extent of PSCs will depend in part on the number of nuclei available. The Polar Ozone and Aerosol Measurement (POAM)II and III satellites have been making observations of <span class="hlt">stratospheric</span> aerosols and Polar <span class="hlt">Stratospheric</span> Clouds (PSCs) since 1994. Recently, we have developed a technique that can discriminate between Type Ia and Ib PSCs using these observations. A statistical approach is employed to demonstrate the robustness of this approach and results are compared with lidar measurements. The technique is used to analyze observations from POAM II and II during Northern Hemisphere winters where significant PSC formation occurred with the objective of exploring Type I PSC formation mechanisms. The different PSCs identified using this method exhibit different growth curve as expressed as extinction versus temperature.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19980237757','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19980237757"><span id="translatedtitle">Fiber-Optic Coupled Lidar Receiver System to Measure <span class="hlt">Stratospheric</span> Ozone</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Harper, David Brent; Elsayed-Ali, Hani</p> <p>1998-01-01</p> <p>The measurement of ozone in the atmosphere has become increasingly important over the past two decades. Significant increases of ozone concentrations in the lower atmosphere, or troposphere, and decreases in the upper atmosphere, or <span class="hlt">stratosphere</span>, have been attributed to man-made causes. High ozone concentrations in the troposphere pose a health hazard to plants and animals and can add to global <span class="hlt">warming</span>. On the other hand, ozone in the <span class="hlt">stratosphere</span> serves as a protective barrier against strong ultraviolet (UV) radiation from the sun. Man-made CFC's (chlorofluorocarbons) act as a catalyst with a free oxygen atom and an ozone molecule to produce two oxygen molecules therefore depleting the protective layer of ozone in the <span class="hlt">stratosphere</span>. The beneficial and harmful effects of ozone require the study of ozone creation and destruction processes in the atmosphere. Therefore, to provide an accurate model of these processes, an ozone lidar system must be able to be used frequently with as large a measurement range as possible. Various methods can be used to measure atmospheric ozone concentrations. These include different airborne and balloon measurements, solar occulation satellite techniques, and the use of lasers in lidar (high detection and ranging,) systems to probe the atmosphere. Typical devices such as weather balloons can only measure within the direct vicinity of the instrument and are therefore used infrequently. Satellites use solar occulation techniques that yield low horizontal and vertical resolution column densities of ozone.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2014ClDy...43.2569K&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2014ClDy...43.2569K&link_type=ABSTRACT"><span id="translatedtitle">-induced continental <span class="hlt">warming</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kamae, Youichi; Watanabe, Masahiro; Kimoto, Masahide; Shiogama, Hideo</p> <p>2014-11-01</p> <p>In this the second of a two-part study, we examine the physical mechanisms responsible for the increasing contrast of the land-sea surface air temperature (SAT) in summertime over the Far East, as observed in recent decades and revealed in future climate projections obtained from a series of transient <span class="hlt">warming</span> and sensitivity experiments conducted under the umbrella of the Coupled Model Intercomparison Project phase 5. On a global perspective, a strengthening of land-sea SAT contrast in the transient <span class="hlt">warming</span> simulations of coupled atmosphere-ocean general circulation models is attributed to an increase in sea surface temperature (SST). However, in boreal summer, the strengthened contrast over the Far East is reproduced only by increasing atmospheric CO2 concentration. In response to SST increase alone, the tropospheric <span class="hlt">warming</span> over the interior of the mid- to high-latitude continents including Eurasia are weaker than those over the surrounding oceans, leading to a weakening of the land-sea SAT contrast over the Far East. Thus, the increasing contrast and associated change in atmospheric circulation over East Asia is explained by CO2-induced continental <span class="hlt">warming</span>. The degree of strengthening of the land-sea SAT contrast varies in different transient <span class="hlt">warming</span> scenarios, but is reproduced through a combination of the CO2-induced positive and SST-induced negative contributions to the land-sea contrast. These results imply that changes of climate patterns over the land-ocean boundary regions are sensitive to future scenarios of CO2 concentration pathways including extreme cases.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2014ACP....1412479H&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2014ACP....1412479H&link_type=ABSTRACT"><span id="translatedtitle"><span class="hlt">Stratospheric</span> lifetime ratio of CFC-11 and CFC-12 from satellite and model climatologies</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hoffmann, L.; Hoppe, C. M.; Müller, R.; Dutton, G. S.; Gille, J. C.; Griessbach, S.; Jones, A.; Meyer, C. I.; Spang, R.; Volk, C. M.; Walker, K. A.</p> <p>2014-11-01</p> <p>Chlorofluorocarbons (CFCs) play a key role in <span class="hlt">stratospheric</span> ozone loss and are strong infrared absorbers that contribute to global <span class="hlt">warming</span>. The <span class="hlt">stratospheric</span> lifetimes of CFCs are a measure of their <span class="hlt">stratospheric</span> loss rates that are needed to determine global <span class="hlt">warming</span> and ozone depletion potentials. We applied the tracer-tracer correlation approach to zonal mean climatologies from satellite measurements and model data to assess the lifetimes of CFCl3 (CFC-11) and CF2Cl2 (CFC-12). We present estimates of the CFC-11/CFC-12 lifetime ratio and the absolute lifetime of CFC-12, based on a reference lifetime of 52 years for CFC-11. We analyzed climatologies from three satellite missions, the Atmospheric Chemistry Experiment-Fourier Transform Spectrometer (ACE-FTS), the HIgh Resolution Dynamics Limb Sounder (HIRDLS), and the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS). We found a CFC-11/CFC-12 lifetime ratio of 0.47±0.08 and a CFC-12 lifetime of 112(96-133) years for ACE-FTS, a ratio of 0.46±0.07 and a lifetime of 113(97-134) years for HIRDLS, and a ratio of 0.46±0.08 and a lifetime of 114(98-136) years for MIPAS. The error-weighted, combined CFC-11/CFC-12 lifetime ratio is 0.46±0.04 and the CFC-12 lifetime estimate is 113(103-124) years. These results agree with the recent <span class="hlt">Stratosphere</span>-troposphere Processes And their Role in Climate (SPARC) reassessment, which recommends lifetimes of 52(43-67) years and 102(88-122) years, respectively. Having smaller uncertainties than the results from other recent studies, our estimates can help to better constrain CFC-11 and CFC-12 lifetime recommendations in future scientific studies and assessments. Furthermore, the satellite observations were used to validate first simulation results from a new coupled model system, which integrates a Lagrangian chemistry transport model into a climate model. For the coupled model we found a CFC-11/CFC-12 lifetime ratio of 0.48±0.07 and a CFC-12 lifetime of 110(95-129) years</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008PhDT........35V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008PhDT........35V"><span id="translatedtitle">The interaction of jet/front systems and mountain waves: Implications for lower <span class="hlt">stratospheric</span> aviation turbulence</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Vollmer, David Russell</p> <p></p> <p>The role of jet streaks and their associated upper-level structures (fronts, troughs, thermal fields, etc.) in enhancing orographically-induced aviation turbulence near and above the tropopause is investigated. The primary hypothesis for this research suggests that there is an optimal configuration for the positioning of upper-level circulations leading to vertically confluent flow and differential thermal advection, forming an intense inversion. Such a configuration may be associated with vertically-intersecting ageostrophic jet circulations or trough-induced differential vertical motions leading to cold air undercutting a <span class="hlt">warm</span> layer aloft, and compression of the <span class="hlt">warm</span> layer in the presence of jet-induced shear. This structure is then perturbed by mountain waves, leading to a downscale cascade of kinetic energy, eventually leading to potential aviation turbulence. Two cases of clear-air turbulence (CAT) are examined using mesoscale numerical simulations. The first case involved a DC-8 attempting to cross the Colorado Front Range when it encountered extreme CAT resulting in loss of part of one wing and an engine. In this case the superposition of two distinct jet features was hypothesized to have established an unusually strong tropopause which allowed strong buoyancy-driven motions to enhance the horizontal shear and turbulent eddies, eventually leading to the turbulent downburst hypothesized to have played a role in damaging the aircraft. The second study used data from the Terrain-Induced Rotor Experiment (T-REX) and examined a turbulent wave-breaking event recorded by a research aircraft in the lower <span class="hlt">stratosphere</span>. A different jet regime was found in this case, with a strong upstream trough and decreasing cyclonic curvature with height above the tropopause and a strong lower <span class="hlt">stratospheric</span> inversion. The vertical variation of static stability in the lower <span class="hlt">stratosphere</span> was found to create a favorable environment for amplification and breaking of the mountain wave</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20130013590','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20130013590"><span id="translatedtitle">Composite Materials With Uncured Epoxy Matrix Exposed in <span class="hlt">Stratosphere</span> During NASA <span class="hlt">Stratospheric</span> Balloon Flight</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Kondyurin, Alexey; Kondyurina, Irina; Bilek, Marcela; de Groh, Kim K.</p> <p>2013-01-01</p> <p>A cassette of uncured composite materials with epoxy resin matrixes was exposed in the <span class="hlt">stratosphere</span> (40 km altitude) over three days. Temperature variations of -76 to 32.5C and pressure up to 2.1 torr were recorded during flight. An analysis of the chemical structure of the composites showed, that the polymer matrix exposed in the <span class="hlt">stratosphere</span> becomes crosslinked, while the ground control materials react by way of polymerization reaction of epoxy groups. The space irradiations are considered to be responsible for crosslinking of the uncured polymers exposed in the <span class="hlt">stratosphere</span>. The composites were cured on Earth after landing. Analysis of the cured composites showed that the polymer matrix remains active under <span class="hlt">stratospheric</span> conditions. The results can be used for predicting curing processes of polymer composites in a free space environment during an orbital space flight.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19770021719','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19770021719"><span id="translatedtitle">International Conference on Problems Related to the <span class="hlt">Stratosphere</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Huntress, W., Jr.</p> <p>1977-01-01</p> <p>The conference focused on four main areas of investigation: laboratory studies and <span class="hlt">stratospheric</span> chemistry and constituents, sources for and chemical budget of <span class="hlt">stratospheric</span> halogen compounds, sources for and chemical budget of <span class="hlt">stratospheric</span> nitrous oxide, and the dynamics of decision making on regulation of potential pollutants of the <span class="hlt">stratosphere</span>. Abstracts of the scientific sessions of the conference as well as complete transcriptions of the panel discussions on sources for an atmospheric budget of holocarbons and nitrous oxide are included. The political, social and economic issues involving regulation of potential <span class="hlt">stratospheric</span> pollutants were examined extensively.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2014EGUGA..16.9692C&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2014EGUGA..16.9692C&link_type=ABSTRACT"><span id="translatedtitle">Recent Increases in <span class="hlt">Stratospheric</span> HCl: <span class="hlt">Stratospheric</span> Dynamics versus the Montreal Protocol</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Chipperfield, Martyn; Mahieu, Emmanuel; Notholt, Justus</p> <p>2014-05-01</p> <p>Long-lived chlorine-containing source gases, such as chlorofluorocarbons (CFCs), are transported into the <span class="hlt">stratosphere</span> where they decompose and cause ozone depletion. Increases in chlorine during the 1970s-1990s resulted in long-term ozone decreases, especially in the polar regions. Following the implementation of the Montreal Protocol, the near-surface chlorine loading was observed to peak in 1993 and, since then, to decrease in line with expectations. After release from source gases in the <span class="hlt">stratosphere</span>, chlorine mainly forms the reservoir HCl, providing an alternative method for monitoring the progress of the Montreal Protocol. A maximum in <span class="hlt">stratospheric</span> HCl was observed around 1996, followed by decay at a rate close to 1%/year, consistent with the tropospheric chlorine peak and known transport timescales. However, we will present total column observations from ground-based FTIR instruments which show an unexpected and significant upturn in <span class="hlt">stratospheric</span> HCl around 2007 in the northern hemisphere. Height-resolved observations from satellite instruments (HALOE, MLS, ACE) confirm this increase and show that it occurs in the lower <span class="hlt">stratosphere</span>. These observations contrast with the ongoing monotonic decrease of near-surface chlorine source gases. Using 3-D model simulations (TOMCAT/SLIMCAT and KASIMA) we attribute this trend anomaly to a slowdown in the NH atmospheric circulation, causing air in the lower <span class="hlt">stratosphere</span> to become more aged with a larger relative conversion of source gases to HCl. An important conclusion is that the Montreal Protocol is still on track and will still lead to long-term decreases in <span class="hlt">stratospheric</span> chlorine. This dynamical variability could also significantly affect the evolution of <span class="hlt">stratospheric</span> ozone and must be accounted for when searching for signs of ozone recovery.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19950031230&hterms=chlorofluorocarbon&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Dchlorofluorocarbon','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19950031230&hterms=chlorofluorocarbon&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Dchlorofluorocarbon"><span id="translatedtitle">Age as a diagnostic of <span class="hlt">stratospheric</span> transport</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Hall, Timothy M.; Plumb, R. Alan</p> <p>1994-01-01</p> <p>Estimates of <span class="hlt">stratospheric</span> age from observations of long-lived trace gases with increasing tropospheric concentrations invoke the implicit assumption that an air parcel has been transported intact from the tropopical tropopause. However, because of rapid and irreversible mixing in the <span class="hlt">stratosphere</span>, a particular air parcel cannot be identified with one that left the troposphere at some prior time. The parcel contains a mix of air with a range of transit times, and the mean value over this range is the most appropriate definition of age. The measured tracer concentration is also a mean over the parcel, but its value depends both on the transit time distribution and the past history of the tracer in the troposphere. In principle, only if the tropospheric concentration is increasing linearly can the age be directly inferred. We illustrate these points by employing both a one-dimensional diffusive analog of <span class="hlt">stratospheric</span> transport, and the general circulation model (GCM) of the Goddard Institute for Space Studies (GISS). Within the limits of the GCM, we estimate the time over which tropospheric tracer concentrations must be approximately linear in order to determine <span class="hlt">stratospheric</span> age unambiguously; the concentration of an exponentially increasing tracer is a function only of age if the growth time constant is greater than about 7 years, which is true for all the chlorofluorocarbons. More rapid source variations (for example, the annual cycle in CO2) have no such direct relationship with age.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19800034778&hterms=Nitrogen+cycle&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3D%2528Nitrogen%2Bcycle%2529','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19800034778&hterms=Nitrogen+cycle&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3D%2528Nitrogen%2Bcycle%2529"><span id="translatedtitle">Nitrogen fertiliser and <span class="hlt">stratospheric</span> ozone - Latitudinal effects</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Whitten, R. C.; Borucki, W. J.; Capone, L. A.; Riegel, C. A.; Turco, R. P.</p> <p>1980-01-01</p> <p>Substantial increases in atmospheric N2O resulting from the increased use of nitrogen fertilizers might cause large (to 10%) decreases in the <span class="hlt">stratospheric</span> ozone content. Such ozone decreases would be caused by catalytic reaction cycles involving odd-nitrogen that is formed by N2O decomposition in the upper <span class="hlt">stratosphere</span>. Turco et al. (1978), using a background chlorine level of 2 ppbv, have shown that if the measured values of specified reactions are used a 50% increase in N2O would lead to a 2.7% increase in the <span class="hlt">stratospheric</span> column density, although the ozone content above 30 km would be reduced by more than 5%; they also estimated (unpublished data) that the change in the ozone column density caused by doubling the N2O abundance would be very close to zero (within about 0.1%). The present paper extends these calculations of N2O/ozone effects to two dimensions, thereby identifying the latitude dependence expected for such ozone perturbations. The effects of changes in <span class="hlt">stratospheric</span> chlorine levels on predicted ozone changes are also discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19860018339&hterms=complex+ion+equilibrium&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dcomplex%2Bion%2Bequilibrium','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19860018339&hterms=complex+ion+equilibrium&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dcomplex%2Bion%2Bequilibrium"><span id="translatedtitle">Ion loss processes in the <span class="hlt">stratosphere</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Prasad, B. S. N.; Chandramma, S.</p> <p>1985-01-01</p> <p>Small ions consisting of aggregates of a few molecules determine th <span class="hlt">stratospheric</span> electrical parameters such as conductivity, mobility, etc. The small ion density is controlled by the ionizing mechanisms for the production of ions and electrons and the loss processes for these charged particles. Ion production in <span class="hlt">stratosphere</span> is chiefly due to galactic cosmic rays, and the loss processes due to recombination and attachment. Free electrons do not exist at <span class="hlt">stratospheric</span> heights. The primary positive ion O2+ and the electrons are converted into complex clusters of positive and negative ions. The equilibrium ion density is governed by the equation of continuity for the production and loss of these ions. In the generalized equation of continuity, the gain or loss of ions due to transport is neglected. When aerosols or particulates are not present in the atmosphere, ions are loss due to ion-ion recombination. In the presence of aerosols, small ions can also be lost by attachment to the aerosols, and thus aerosols are likely to cause perturbations in the <span class="hlt">stratosphere</span> electrification. A simplified model approach is adopted to study the effect of aerosols on the equilibrium ion density. The results of the analysis for the equatorial station Thumba (8.5 deg N) are presented.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li class="active"><span>22</span></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_22 --> <div id="page_23" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li class="active"><span>23</span></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="441"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19790056607&hterms=N2O+Absorption+Lines&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3DN2O%2BAbsorption%2BLines','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19790056607&hterms=N2O+Absorption+Lines&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3DN2O%2BAbsorption%2BLines"><span id="translatedtitle"><span class="hlt">Stratospheric</span> sounding by infrared heterodyne spectroscopy</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Abbas, M. M.; Kunde, V. G.; Mumma, M. J.; Kostiuk, T.; Buhl, D.; Frerking, M. A.</p> <p>1979-01-01</p> <p>Intensity profiles of infrared spectral lines of <span class="hlt">stratospheric</span> constituents can be fully resolved with a heterodyne spectrometer of sufficiently high resolution (approximately 5 MHz = 0.000167 kaysers at 10 microns). The constituents' vertical distributions can then be evaluated accurately by analytic inversion of the measured line profiles. Estimates of the detection sensitivity of a heterodyne receiver are given in terms of minimum detectable volume mixing ratios of <span class="hlt">stratospheric</span> constituents, indicating a large number of minor constituents which can be studied. <span class="hlt">Stratospheric</span> spectral line shapes and the resolution required to measure them are discussed in light of calculated synthetic line profiles for some <span class="hlt">stratospheric</span> molecules in a model atmosphere. The inversion technique for evaluation of gas concentration profiles is briefly described, and applications to synthetic lines of O3, CO2, CH4, and N2O are given. Some recent heterodyne measurements of CO2 and O3 absorption lines are analytically inverted, and the vertical distributions of the two gases are determined.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20020010116','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20020010116"><span id="translatedtitle">Large-Scale <span class="hlt">Stratospheric</span> Transport Processes</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Plumb, R. Alan</p> <p>2001-01-01</p> <p>The paper discusses the following: 1. The Brewer-Dobson circulation: tropical upwelling. 2. Mixing into polar vortices. 3. The latitudinal structure of "age" in the <span class="hlt">stratosphere</span>. 4. The subtropical "tracer edges". 5. Transport in the lower troposphere. 6. Tracer modeling during SOLVE. 7. 3D modeling of "mean age". 8. Models and measurements II.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20020039144','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20020039144"><span id="translatedtitle">Chemistry-Climate Models of the <span class="hlt">Stratosphere</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Austin, J.; Shindell, D.; Bruehl, C.; Dameris, M.; Manzini, E.; Nagashima, T.; Newman, P.; Pawson, S.; Pitari, G.; Rozanov, E.; Bhartia, P. K. (Technical Monitor)</p> <p>2001-01-01</p> <p>Over the last decade, improved computer power has allowed three-dimensional models of the <span class="hlt">stratosphere</span> to be developed that can be used to simulate polar ozone levels over long periods. This paper compares the meteorology between these models, and discusses the future of polar ozone levels over the next 50 years.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryId=38131&keyword=buy&actType=&TIMSType=+&TIMSSubTypeID=&DEID=&epaNumber=&ntisID=&archiveStatus=Both&ombCat=Any&dateBeginCreated=&dateEndCreated=&dateBeginPublishedPresented=&dateEndPublishedPresented=&dateBeginUpdated=&dateEndUpdated=&dateBeginCompleted=&dateEndCompleted=&personID=&role=Any&journalID=&publisherID=&sortBy=revisionDate&count=50&CFID=64199043&CFTOKEN=37830791','EPA-EIMS'); return false;" href="http://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryId=38131&keyword=buy&actType=&TIMSType=+&TIMSSubTypeID=&DEID=&epaNumber=&ntisID=&archiveStatus=Both&ombCat=Any&dateBeginCreated=&dateEndCreated=&dateBeginPublishedPresented=&dateEndPublishedPresented=&dateBeginUpdated=&dateEndUpdated=&dateBeginCompleted=&dateEndCompleted=&personID=&role=Any&journalID=&publisherID=&sortBy=revisionDate&count=50&CFID=64199043&CFTOKEN=37830791"><span id="translatedtitle">SUCCESS OF EPA'S <span class="hlt">STRATOSPHERIC</span> OZONE ENGINEERING RESEARCH</span></a></p> <p><a target="_blank" href="http://oaspub.epa.gov/eims/query.page">EPA Science Inventory</a></p> <p></p> <p></p> <p>The paper summarizes recent successes in, as well as work in progress (with the cooperation of industry) on, EPA's <span class="hlt">stratospheric</span> ozone engineering research. he Montreal Protocol and U.S. regulations implementing the Protocol necessitate that engineering solutions be found and imp...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19820010896','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19820010896"><span id="translatedtitle">The <span class="hlt">Stratosphere</span> 1981: Theory and measurements</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p></p> <p>1982-01-01</p> <p>Measurements of trace species are compared with theoretical estimates and the similarities and the differences between the two sets of data are discussed. The theoretical predictions are compared with long term trends in both column content and altitude profile of ozone as observed from ground-based and satellite instruments. The chemical kinetics and photochemistry of the <span class="hlt">stratosphere</span> were reviewed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008cosp...37.2419P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008cosp...37.2419P"><span id="translatedtitle">Space and Earth Observations from <span class="hlt">Stratospheric</span> Balloons</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Peterzen, Steven; Ubertini, Pietro; Masi, Silvia; Ibba, Roberto; Ivano, Musso; Cardillo, Andrea; Romeo, Giovanni; Dragøy, Petter; Spoto, Domenico</p> <p></p> <p><span class="hlt">Stratospheric</span> balloons are rapidly becoming the vehicle of choice for near space investigations and earth observations by a variety of science disciplines. With the ever increasing research into climatic change, instruments suspended from <span class="hlt">stratospheric</span> balloons offer the science team a unique, stable and reusable platform that can circle the Earth in the polar region or equatorial zone for thirty days or more. The Italian Space Agency (ASI) in collaboration with Andoya Rocket Range (Andenes, Norway) has opened access in the far northern latitudes above 78o N from Longyearbyen, Svalbard. In 2006 the first Italian UltraLite Long Duration Balloon was launched from Baia Terra Nova, Mario Zuchelli station in Antarctica and now ASI is setting up for the their first equatorial <span class="hlt">stratospheric</span> launch from their satellite receiving station and rocket launch site in Malindi, Kenya. For the equatorial missions we have analysed the statistical properties of trajectories considering the biennal oscillation and the seasonal effects of the <span class="hlt">stratospheric</span> winds. Maintaining these launch sites offer the science community 3 point world coverage for heavy lift balloons as well as the rapidly deployed Ultralight payloads and TM system ASI developed to use for test platforms, micro experiments, as well as a comprehensive student pilot program</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011RvGeo..49.3003G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011RvGeo..49.3003G"><span id="translatedtitle">The Extratropical Upper Troposphere and Lower <span class="hlt">Stratosphere</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gettelman, A.; Hoor, P.; Pan, L. L.; Randel, W. J.; Hegglin, M. I.; Birner, T.</p> <p>2011-08-01</p> <p>The extratropical upper troposphere and lower <span class="hlt">stratosphere</span> (Ex-UTLS) is a transition region between the <span class="hlt">stratosphere</span> and the troposphere. The Ex-UTLS includes the tropopause, a strong static stability gradient and dynamic barrier to transport. The barrier is reflected in tracer profiles. This region exhibits complex dynamical, radiative, and chemical characteristics that place stringent spatial and temporal requirements on observing and modeling systems. The Ex-UTLS couples the <span class="hlt">stratosphere</span> to the troposphere through chemical constituent transport (of, e.g., ozone), by dynamically linking the <span class="hlt">stratospheric</span> circulation with tropospheric wave patterns, and via radiative processes tied to optically thick clouds and clear-sky gradients of radiatively active gases. A comprehensive picture of the Ex-UTLS is presented that brings together different definitions of the tropopause, focusing on observed dynamical and chemical structure and their coupling. This integral view recognizes that thermal gradients and dynamic barriers are necessarily linked, that these barriers inhibit mixing and give rise to specific trace gas distributions, and that there are radiative feedbacks that help maintain this structure. The impacts of 21st century anthropogenic changes to the atmosphere due to ozone recovery and climate change will be felt in the Ex-UTLS, and recent simulations of these effects are summarized and placed in context.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryId=128956&keyword=Ozone+AND+depletion&actType=&TIMSType=+&TIMSSubTypeID=&DEID=&epaNumber=&ntisID=&archiveStatus=Both&ombCat=Any&dateBeginCreated=&dateEndCreated=&dateBeginPublishedPresented=&dateEndPublishedPresented=&dateBeginUpdated=&dateEndUpdated=&dateBeginCompleted=&dateEndCompleted=&personID=&role=Any&journalID=&publisherID=&sortBy=revisionDate&count=50&CFID=77945317&CFTOKEN=82490758','EPA-EIMS'); return false;" href="http://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryId=128956&keyword=Ozone+AND+depletion&actType=&TIMSType=+&TIMSSubTypeID=&DEID=&epaNumber=&ntisID=&archiveStatus=Both&ombCat=Any&dateBeginCreated=&dateEndCreated=&dateBeginPublishedPresented=&dateEndPublishedPresented=&dateBeginUpdated=&dateEndUpdated=&dateBeginCompleted=&dateEndCompleted=&personID=&role=Any&journalID=&publisherID=&sortBy=revisionDate&count=50&CFID=77945317&CFTOKEN=82490758"><span id="translatedtitle"><span class="hlt">STRATOSPHERIC</span> OZONE PROTECTION: AN EPA ENGINEERING PERSPECTIVE</span></a></p> <p><a target="_blank" href="http://oaspub.epa.gov/eims/query.page">EPA Science Inventory</a></p> <p></p> <p></p> <p>Chlorine released into the atmosphere is a major factor in the depletion of the protective <span class="hlt">stratospheric</span> ozone layer. The Montreal Protocol, as amended in 1990, and the Clean Air Act Amendments of 1990, address the limits and reduction schedules to be placed on chlorine- and brom...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://eric.ed.gov/?q=aerosol&pg=2&id=EJ349576','ERIC'); return false;" href="http://eric.ed.gov/?q=aerosol&pg=2&id=EJ349576"><span id="translatedtitle"><span class="hlt">Stratospheric</span> Aerosols: The Transfer of Scientific Information.</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Feidler, Anita; Hurt, C. D.</p> <p>1986-01-01</p> <p>Examines information transfer in atmospheric physics by tracing one paper through five years of citations and suggesting patterns for highly cited papers. The results are also discussed in terms of information transfer in a popularized environment, as <span class="hlt">stratospheric</span> aerosols have been prominently discussed in the popular press. (Author/EM)</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19920005320','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19920005320"><span id="translatedtitle"><span class="hlt">Stratospheric</span> General Circulation with Chemistry Model (SGCCM)</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Rood, Richard B.; Douglass, Anne R.; Geller, Marvin A.; Kaye, Jack A.; Nielsen, J. Eric; Rosenfield, Joan E.; Stolarski, Richard S.</p> <p>1990-01-01</p> <p>In the past two years constituent transport and chemistry experiments have been performed using both simple single constituent models and more complex reservoir species models. Winds for these experiments have been taken from the data assimilation effort, <span class="hlt">Stratospheric</span> Data Analysis System (STRATAN).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19930029492&hterms=infrared+astronomy&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3D%2528infrared%2Bastronomy%2529','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19930029492&hterms=infrared+astronomy&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3D%2528infrared%2Bastronomy%2529"><span id="translatedtitle">SOFIA - <span class="hlt">Stratospheric</span> Observatory For Infrared Astronomy</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Erickson, E. F.</p> <p>1992-01-01</p> <p>The features and scientific aims of SOFIA (<span class="hlt">Stratospheric</span> Observatory For Infrared Astronomy), a planned 2.5 m telescope to be installed in an aircraft and operated at altitudes from 41,000 to 46,000 ft, are discussed. A brief overview of the SOFIA program is given.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/6956876','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/6956876"><span id="translatedtitle">Sulfate aerosols and polar <span class="hlt">stratospheric</span> cloud formation</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Tolbert, M.A. )</p> <p>1994-04-22</p> <p>Before the discovery of the Antarctic ozone hole, it was generally assumed that gas-phase chemical reactions controlled the abundance of <span class="hlt">stratospheric</span> ozone. However, the massive springtime ozone losses over Antarctica first reported by Farman et al in 1985 could not be explained on the basis of gas-phase chemistry alone. In 1986, Solomon et al suggested that chemical reactions occurring on the surfaces of polar <span class="hlt">stratospheric</span> clouds (PSCs) could be important for the observed ozone losses. Since that time, an explosion of laboratory, field, and theoretical research in heterogeneous atmospheric chemistry has occurred. Recent work has indicated that the most important heterogeneous reaction on PSCs is ClONO[sub 2] + HCl [yields] Cl[sub 2] + HNO[sub 3]. This reaction converts inert chlorine into photochemically active Cl[sub 2]. Photolysis of Cl[sub 2] then leads to chlorine radicals capable of destroying ozone through very efficient catalytic chain reactions. New observations during the second Airborne Arctic <span class="hlt">Stratospheric</span> Expedition found stoichiometric loss of ClONO[sub 2] and HCl in air processed by PSCs in accordance with reaction 1. Attention is turning toward understanding what kinds of aerosols form in the <span class="hlt">stratospheric</span>, their formation mechanism, surface area, and specific chemical reactivity. Some of the latest findings, which underline the importance of aerosols, were presented at a recent National Aeronautics and Space Administration workshop in Boulder, Colorado.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013GeoRL..40.2796B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013GeoRL..40.2796B"><span id="translatedtitle">Climate impact of <span class="hlt">stratospheric</span> ozone recovery</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bekki, S.; Rap, A.; Poulain, V.; Dhomse, S.; Marchand, M.; Lefevre, F.; Forster, P. M.; Szopa, S.; Chipperfield, M. P.</p> <p>2013-06-01</p> <p><span class="hlt">stratospheric</span> ozone depletion has acted to cool the Earth's surface. As the result of the phase-out of anthropogenic halogenated compounds emissions, <span class="hlt">stratospheric</span> ozone is projected to recover and its radiative forcing (RF-O3 ~ -0.05 W/m2 presently) might therefore be expected to decay in line with ozone recovery itself. Using results from chemistry-climate models, we find that, although model projections using a standard greenhouse gas scenario broadly agree on the future evolution of global ozone, they strongly disagree on RF-O3 because of a large model spread in ozone changes in a narrow (several km thick) layer, in the northern lowermost <span class="hlt">stratosphere</span>. Clearly, future changes in global <span class="hlt">stratospheric</span> ozone cannot be considered an indicator of its overall RF. The multi-model mean RF-O3 estimate for 2100 is +0.06 W/m2 but with a range such that it could remain negative throughout this century or change sign and reach up to ~0.25 W/m2.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016RvGeo..54..278K&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016RvGeo..54..278K&link_type=ABSTRACT"><span id="translatedtitle"><span class="hlt">Stratospheric</span> aerosol—Observations, processes, and impact on climate</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kremser, Stefanie; Thomason, Larry W.; Hobe, Marc; Hermann, Markus; Deshler, Terry; Timmreck, Claudia; Toohey, Matthew; Stenke, Andrea; Schwarz, Joshua P.; Weigel, Ralf; Fueglistaler, Stephan; Prata, Fred J.; Vernier, Jean-Paul; Schlager, Hans; Barnes, John E.; Antuña-Marrero, Juan-Carlos; Fairlie, Duncan; Palm, Mathias; Mahieu, Emmanuel; Notholt, Justus; Rex, Markus; Bingen, Christine; Vanhellemont, Filip; Bourassa, Adam; Plane, John M. C.; Klocke, Daniel; Carn, Simon A.; Clarisse, Lieven; Trickl, Thomas; Neely, Ryan; James, Alexander D.; Rieger, Landon; Wilson, James C.; Meland, Brian</p> <p>2016-06-01</p> <p>Interest in <span class="hlt">stratospheric</span> aerosol and its role in climate have increased over the last decade due to the observed increase in <span class="hlt">stratospheric</span> aerosol since 2000 and the potential for changes in the sulfur cycle induced by climate change. This review provides an overview about the advances in <span class="hlt">stratospheric</span> aerosol research since the last comprehensive assessment of <span class="hlt">stratospheric</span> aerosol was published in 2006. A crucial development since 2006 is the substantial improvement in the agreement between in situ and space-based inferences of <span class="hlt">stratospheric</span> aerosol properties during volcanically quiescent periods. Furthermore, new measurement systems and techniques, both in situ and space based, have been developed for measuring physical aerosol properties with greater accuracy and for characterizing aerosol composition. However, these changes induce challenges to constructing a long-term <span class="hlt">stratospheric</span> aerosol climatology. Currently, changes in <span class="hlt">stratospheric</span> aerosol levels less than 20% cannot be confidently quantified. The volcanic signals tend to mask any nonvolcanically driven change, making them difficult to understand. While the role of carbonyl sulfide as a substantial and relatively constant source of <span class="hlt">stratospheric</span> sulfur has been confirmed by new observations and model simulations, large uncertainties remain with respect to the contribution from anthropogenic sulfur dioxide emissions. New evidence has been provided that <span class="hlt">stratospheric</span> aerosol can also contain small amounts of nonsulfate matter such as black carbon and organics. Chemistry-climate models have substantially increased in quantity and sophistication. In many models the implementation of <span class="hlt">stratospheric</span> aerosol processes is coupled to radiation and/or <span class="hlt">stratospheric</span> chemistry modules to account for relevant feedback processes.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20160010788&hterms=Climate&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3DClimate','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20160010788&hterms=Climate&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3DClimate"><span id="translatedtitle"><span class="hlt">Stratospheric</span> Aerosol--Observations, Processes, and Impact on Climate</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Kresmer, Stefanie; Thomason, Larry W.; von Hobe, Marc; Hermann, Markus; Deshler, Terry; Timmreck, Claudia; Toohey, Matthew; Stenke, Andrea; Schwarz, Joshua P.; Weigel, Ralf; Fueglistaler, Stephan; Prata, Fred J.; Vernier, Jean-Paul; Schlager, Hans; Barnes, John E.; Antuna-Marrero, Juan-Carlos; Fairlie, Duncan; Palm, Mathias; Mahieu, Emmanuel; Notholt, Justus; Rex, Markus; Bingen, Christine; Vanhellemont, Filip; Bourassa, Adam; Plane, John M. C.; Klocke, Daniel; Carn, Simon A.; Clarisse, Lieven; Trickl, Thomas; Neeley, Ryan; James, Alexander D.; Rieger, Landon; Wilson, James C.; Meland, Brian</p> <p>2016-01-01</p> <p>Interest in <span class="hlt">stratospheric</span> aerosol and its role in climate have increased over the last decade due to the observed increase in <span class="hlt">stratospheric</span> aerosol since 2000 and the potential for changes in the sulfur cycle induced by climate change. This review provides an overview about the advances in <span class="hlt">stratospheric</span> aerosol research since the last comprehensive assessment of <span class="hlt">stratospheric</span> aerosol was published in 2006. A crucial development since 2006 is the substantial improvement in the agreement between in situ and space-based inferences of <span class="hlt">stratospheric</span> aerosol properties during volcanically quiescent periods. Furthermore, new measurement systems and techniques, both in situ and space based, have been developed for measuring physical aerosol properties with greater accuracy and for characterizing aerosol composition. However, these changes induce challenges to constructing a long-term <span class="hlt">stratospheric</span> aerosol climatology. Currently, changes in <span class="hlt">stratospheric</span> aerosol levels less than 20% cannot be confidently quantified. The volcanic signals tend to mask any nonvolcanically driven change, making them difficult to understand. While the role of carbonyl sulfide as a substantial and relatively constant source of <span class="hlt">stratospheric</span> sulfur has been confirmed by new observations and model simulations, large uncertainties remain with respect to the contribution from anthropogenic sulfur dioxide emissions. New evidence has been provided that <span class="hlt">stratospheric</span> aerosol can also contain small amounts of nonsulfatematter such as black carbon and organics. Chemistry-climate models have substantially increased in quantity and sophistication. In many models the implementation of <span class="hlt">stratospheric</span> aerosol processes is coupled to radiation and/or <span class="hlt">stratospheric</span> chemistry modules to account for relevant feedback processes.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20020064962&hterms=scarcity&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dscarcity','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20020064962&hterms=scarcity&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dscarcity"><span id="translatedtitle"><span class="hlt">Stratospheric</span> Sulfuric Acid and Black Carbon Aerosol Measured During POLARIS and its Role in Ozone Chemistry</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Strawa, Anthony W.; Pueschel, R. F.; Drdla, K.; Verma, S.; Gore, Warren J. (Technical Monitor)</p> <p>1998-01-01</p> <p><span class="hlt">Stratospheric</span> aerosol can affect the environment in three ways. Sulfuric acid aerosol have been shown to act as sites for the reduction of reactive nitrogen and chlorine and as condensation sites to form Polar <span class="hlt">Stratospheric</span> Clouds, under very cold conditions, which facilitate ozone depletion. Recently, modeling studies have suggested a link between BCA (Black Carbon Aerosol) and ozone chemistry. These studies suggest that HNO3, NO2, and O3 may be reduced heterogeneously on BCA particles. The ozone reaction converts ozone to oxygen molecules, while HNO3 and NO2 react to form NOx. Finally, a buildup of BCA could reduce the single-scatter albedo of aerosol below a value of 0.98, a critical value that has been postulated to change the effect of <span class="hlt">stratospheric</span> aerosol from cooling to <span class="hlt">warming</span>. Correlations between measured BCA amounts and aircraft usage have been reported. Attempts to link BCA to ozone chemistry and other <span class="hlt">stratospheric</span> processes have been hindered by questions concerning the amount of BCA that exists in the <span class="hlt">stratosphere</span>, the magnitude of reaction probabilities, and the scarcity of BCA measurements. The Ames Wire Impactors (AWI) participated in POLARIS as part of the complement of experiments on the NASA ER-2. One of our main objectives was to determine the amount of aerosol surface area, particularly BCA, available for reaction with <span class="hlt">stratospheric</span> constituents and assess if possible, the importance of these reactions. The AWI collects aerosol and BCA particles on thin Palladium wires that are exposed to the ambient air in a controlled manner. The samples are returned to the laboratory for subsequent analysis. The product of the AWI analysis is the size, surface area, and volume distributions, morphology and elemental composition of aerosol and BCA. This paper presents results from our experiments during POLARIS and puts these measurements in the context of POLARIS and other missions in which we have participated. It describes modifications to the AWI data</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFMSM21C2205H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFMSM21C2205H"><span id="translatedtitle">The Evolution of Hydrocarbon Compounds in Saturn's <span class="hlt">Stratosphere</span> During the 2010 Northern Storm</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hesman, B. E.; Bjoraker, G. L.; Achterberg, R. K.; Sada, P. V.; Jennings, D. E.; Lunsford, A. W.; Sinclair, J.; Romani, P. N.; Boyle, R.; Fletcher, L. N.; Irwin, P.</p> <p>2013-12-01</p> <p>The massive eruption at 40N (planetographic latitude) in December 2010 has produced significant and long-lived changes in temperature and species abundances in Saturn's northern hemisphere (Hesman et al. 2012a, Fletcher et al. 2012). The northern storm region has been observed on many occasions between January 2011 and June of 2012 by Cassini's Composite Infrared Spectrometer (CIRS). In this time period, temperatures in regions referred to as 'beacons' (<span class="hlt">warm</span> regions in the <span class="hlt">stratosphere</span> at certain longitudes in the storm latitude) became significantly warmer than pre-storm values of 140K. In this period hydrocarbon emission greatly increased; however, this increased emission could not be attributed due to the temperature changes alone for many of these species (Hesman et al. 2012b, Bjoraker et al 2012). The unique nature of the <span class="hlt">stratospheric</span> beacons also resulted in the detection of ethylene (C2H4) using CIRS. These beacon regions have also led to the identification of rare hydrocarbon species such as C4H2 and C3H4 in the <span class="hlt">stratosphere</span>. These species are all expected from photochemical processes in the <span class="hlt">stratosphere</span>, however high temperatures, unusual chemistry, or dynamics are enhancing these species. The exact cause of these enhancements is still under investigation. Ground-based observations were performed using the high-resolution spectrometer Celeste in May 2011 to confirm the CIRS detection of C2H4 and to study its spectral signatures at higher spectral resolution. In order to follow the evolution of its emission further observations were performed in July 2011 and March 2012. These observations are being used in conjunction with the CIRS observations to investigate the source of the approximately 100-fold increase of ethylene in the <span class="hlt">stratospheric</span> beacon. The time evolution of hydrocarbon emission from C2H2, C2H4, C2H6, C3H4, and C4H2 in Saturn's Northern Storm beacon regions will be discussed. References: Bjoraker, G., B.E. Hesman, R.K. Achterberg, P.N. Romani</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/24533155','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/24533155"><span id="translatedtitle">A risk-based framework for assessing the effectiveness of <span class="hlt">stratospheric</span> aerosol geoengineering.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Ferraro, Angus J; Charlton-Perez, Andrew J; Highwood, Eleanor J</p> <p>2014-01-01</p> <p>Geoengineering by <span class="hlt">stratospheric</span> aerosol injection has been proposed as a policy response to <span class="hlt">warming</span> from human emissions of greenhouse gases, but it may produce unequal regional impacts. We present a simple, intuitive risk-based framework for classifying these impacts according to whether geoengineering increases or decreases the risk of substantial climate change, with further classification by the level of existing risk from climate change from increasing carbon dioxide concentrations. This framework is applied to two climate model simulations of geoengineering counterbalancing the surface <span class="hlt">warming</span> produced by a quadrupling of carbon dioxide concentrations, with one using a layer of sulphate aerosol in the lower <span class="hlt">stratosphere</span>, and the other a reduction in total solar irradiance. The solar dimming model simulation shows less regional inequality of impacts compared with the aerosol geoengineering simulation. In the solar dimming simulation, 10% of the Earth's surface area, containing 10% of its population and 11% of its gross domestic product, experiences greater risk of substantial precipitation changes under geoengineering than under enhanced carbon dioxide concentrations. In the aerosol geoengineering simulation the increased risk of substantial precipitation change is experienced by 42% of Earth's surface area, containing 36% of its population and 60% of its gross domestic product. PMID:24533155</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EGUGA..1815345D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EGUGA..1815345D"><span id="translatedtitle">Seasonal prediction of the NAO from <span class="hlt">stratospheric</span> and tropospheric indicators for different data products and index definitions</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Domeisen, Daniela; Koszalka, Inga</p> <p>2016-04-01</p> <p>Skilful winter forecasts of the North Atlantic Oscillation (NAO) anomaly - a proxy for weather conditions in Europe - are of crucial importance to industry applications and power supply policies at the local and regional level. These forecasts are achieved by either dynamical models, based on deterministic equations, or statistical models exploring correlations and teleconnections between key <span class="hlt">stratospheric</span> and tropospheric variables and the NAO index. The response to anomalies in <span class="hlt">stratospheric</span> polar cap temperatures, as e.g. the negative NAO response observed after major <span class="hlt">stratospheric</span> sudden <span class="hlt">warming</span> events, is quite reliably reproduced in seasonal prediction models. The strength of this response depends on the model and the strength and vertical extent of the forcing, which is modulated by teleconnections affecting the <span class="hlt">stratosphere</span>, such as El Nino and the Quasi-Biennial Oscillation. In addition, various teleconnections with tropospheric origin tend to affect the prediction of the NAO. Both types of models - dynamical and statistical models - show some skill in predicting the NAO index anomaly on seasonal timescales, but this skill exhibits a strong year-to-year variability, since the connection between the NAO and the different predictors including the teleconnection mechanisms are not yet well understood. We present results comparing the statistical properties of the NAO index time series based on different reanalysis datasets and different index definitions with respect to the NAO winter variability, and their relation to statistical indicators used in weather forecasting for different winter regimes in Europe.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2002EGSGA..27.4020B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2002EGSGA..27.4020B"><span id="translatedtitle">Arctic <span class="hlt">Stratospheric</span> Temperature In The Winters 1999/2000 and 2000/2001: A Quantitative Assessment and Microphysical Implications</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Buss, S.; Wernli, H.; Peter, T.; Kivi, R.; Bui, T. P.; Kleinböhl, A.; Schiller, C.</p> <p></p> <p><span class="hlt">Stratospheric</span> winter temperatures play a key role in the chain of microphysical and chemical processes that lead to the formation of polar <span class="hlt">stratospheric</span> clouds (PSCs), chlorine activation and eventually to <span class="hlt">stratospheric</span> ozone depletion. Here the tempera- ture conditions during the Arctic winters 1999/2000 and 2000/2001 are quantitatively investigated using observed profiles of water vapour and nitric acid, and tempera- tures from high-resolution radiosondes and aircraft observations, global ECMWF and UKMO analyses and mesoscale model simulations over Scandinavia and Greenland. The ECMWF model resolves parts of the gravity wave activity and generally agrees well with the observations. However, for the very cold temperatures near the ice frost point the ECMWF analyses have a <span class="hlt">warm</span> bias of 1-6 K compared to radiosondes. For the mesoscale model HRM, this bias is generally reduced due to a more accurate rep- resentation of gravity waves. Quantitative estimates of the impact of the mesoscale temperature perturbations indicates that over Scandinavia and Greenland the wave- induced <span class="hlt">stratospheric</span> cooling (as simulated by the HRM) affects only moderately the estimated chlorine activation and homogeneous NAT particle formation, but strongly enhances the potential for ice formation.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li class="active"><span>23</span></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_23 --> <div id="page_24" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li class="active"><span>24</span></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="461"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014ACPD...14..651L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014ACPD...14..651L"><span id="translatedtitle">Convective transport of very-short-lived bromocarbons to the <span class="hlt">stratosphere</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Liang, Q.; Atlas, E.; Blake, D.; Dorf, M.; Pfeilsticker, K.; Schauffler, S.</p> <p>2014-01-01</p> <p>We use the NASA GEOS Chemistry Climate Model (GEOSCCM) to quantify the contribution of two most important brominated very short-lived substances (VSLS), bromoform (CHBr3) and dibromomethane (CH2Br2), to <span class="hlt">stratospheric</span> bromine and its sensitivity to convection strength. Model simulations suggest that the most active transport of VSLS from the marine boundary layer through the tropopause occurs over the tropical Indian Ocean, the Western Pacific <span class="hlt">warm</span> pool, and off the Pacific coast of Mexico. Together, convective lofting of CHBr3 and CH2Br2 and their degradation products supplies ∼8 ppt total bromine to the base of the Tropical Tropopause Layer (TTL, ∼150 hPa), similar to the amount of VSLS organic bromine available in the marine boundary layer (∼7.8-8.4 ppt) in the above active convective lofting regions. Of the total ∼8 ppt VSLS-originated bromine that enters the base of TTL at ∼150 hPa, half is in the form of source gas injection (SGI) and half as product gas injection (PGI). Only a small portion (< 10%) the VSLS-originated bromine is removed via wet scavenging in the TTL before reaching the lower <span class="hlt">stratosphere</span>. On global and annual average, CHBr3 and CH2Br2, together, contribute ∼7.7 pptv to the present-day inorganic bromine in the <span class="hlt">stratosphere</span>. However, varying model deep convection strength between maximum and minimum convection conditions can introduce a ∼2.6 pptv uncertainty in the contribution of VSLS to inorganic bromine in the <span class="hlt">stratosphere</span> (BryVSLS). Contrary to the conventional wisdom, minimum convection condition leads to a larger BryVSLS as the reduced scavenging in soluble product gases, thus a significant increase in PGI (2-3 ppt), greatly exceeds the relative minor decrease in SGI (a few 10ths ppt).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20140005411','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20140005411"><span id="translatedtitle">Convective Transport of Very-short-lived Bromocarbons to the <span class="hlt">Stratosphere</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Liang, Qing; Atlas, Elliot Leonard; Blake, Donald Ray; Dorf, Marcel; Pfeilsticker, Klaus August; Schauffler, Sue Myhre</p> <p>2014-01-01</p> <p>We use the NASA GEOS Chemistry Climate Model (GEOSCCM) to quantify the contribution of two most important brominated very short-lived substances (VSLS), bromoform (CHBr3) and dibromomethane (CH2Br2), to <span class="hlt">stratospheric</span> bromine and its sensitivity to convection strength. Model simulations suggest that the most active transport of VSLS from the marine boundary layer through the tropopause occurs over the tropical Indian Ocean, the Western Pacific <span class="hlt">warm</span> pool, and off the Pacific coast of Mexico. Together, convective lofting of CHBr3 and CH2Br2 and their degradation products supplies 8 ppt total bromine to the base of the Tropical Tropopause Layer (TTL, 150 hPa), similar to the amount of VSLS organic bromine available in the marine boundary layer (7.8-8.4 ppt) in the above active convective lofting regions. Of the total 8 ppt VSLS-originated bromine that enters the base of TTL at 150 hPa, half is in the form of source gas injection (SGI) and half as product gas injection (PGI). Only a small portion (< 10%) the VSLS-originated bromine is removed via wet scavenging in the TTL before reaching the lower <span class="hlt">stratosphere</span>. On global and annual average, CHBr3 and CH2Br2, together, contribute 7.7 pptv to the present-day inorganic bromine in the <span class="hlt">stratosphere</span>. However, varying model deep convection strength between maximum and minimum convection conditions can introduce a 2.6 pptv uncertainty in the contribution of VSLS to inorganic bromine in the <span class="hlt">stratosphere</span> (BryVSLS). Contrary to the conventional wisdom, minimum convection condition leads to a larger BryVSLS as the reduced scavenging in soluble product gases, thus a significant increase in PGI (2-3 ppt), greatly exceeds the relative minor decrease in SGI (a few 10ths ppt.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EGUGA..18.2367T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EGUGA..18.2367T"><span id="translatedtitle">Challenges to producing a long-term <span class="hlt">stratospheric</span> aerosol climatology for chemistry and climate</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Thomason, Larry; Vernier, Jean-Paul; Bourassa, Adam; Rieger, Landon; Luo, Beiping; Peter, Thomas; Arfeuille, Florian</p> <p>2016-04-01</p> <p><span class="hlt">Stratospheric</span> aerosol data sets are key inputs for climate models (GCMs, CCMs) particularly for understanding the role of volcanoes on climate and as a surrogate for understanding the potential of human-derived <span class="hlt">stratospheric</span> aerosol as mitigation for global <span class="hlt">warming</span>. In addition to supporting activities of individual climate models, the data sets also act as a historical input to the activities of SPARC's Chemistry-Climate Model Initiative (CCMI) and the World Climate Research Programme's Coupled Model Intercomparison Project (CMIP). One such data set was produced in 2004 as a part of the SPARC Assessment of <span class="hlt">Stratospheric</span> Aerosol Properties (ASAP), extending from 1979 and 2004. It was primarily constructed from the <span class="hlt">Stratospheric</span> Aerosol and Gas Experiment series of instruments but supplemented by data from other space-based sources and a number of ground-based and airborne instruments. Updates to this data set have expanded the timeframe to span from 1850 through 2014 through the inclusion of data from additional sources, such as photometer data and ice core analyses. Fundamentally, there are limitations to the reliability of the optical properties of aerosol inferred from even the most complete single instrument data sets. At the same time, the heterogeneous nature of the underlying data to this historical data set produces considerable challenges to the production of a climate data set which is both homogeneous and reliable throughout its timespan. In this presentation, we will discuss the impact of this heterogeneity showing specific examples such as the SAGE II to OSIRIS/CALIPSO transition in 2005. Potential solutions to these issues will also be discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015EGUGA..17.7601N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015EGUGA..17.7601N"><span id="translatedtitle">Comparison of <span class="hlt">stratospheric</span> temperature profiles from a ground-based microwave radiometer with lidar, radiosonde and satellite data</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Navas-Guzmán, Francisco; Kämpfer, Niklaus; Haefele, Alexander; Keckhut, Philippe; Hauchecorne, Alain</p> <p>2015-04-01</p> <p>The importance of the knowledge of the temperature structure in the atmosphere has been widely recognized. Temperature is a key parameter for dynamical, chemical and radiative processes in the atmosphere. The cooling of the <span class="hlt">stratosphere</span> is an indicator for climate change as it provides evidence of natural and anthropogenic climate forcing just like surface <span class="hlt">warming</span> ( [1] and references therein). However, our understanding of the observed <span class="hlt">stratospheric</span> temperature trend and our ability to test simulations of the <span class="hlt">stratospheric</span> response to emissions of greenhouse gases and ozone depleting substances remains limited. <span class="hlt">Stratospheric</span> long-term datasets are sparse and obtained trends differ from one another [1]. Therefore it is important that in the future such datasets are generated. Different techniques allow to measure <span class="hlt">stratospheric</span> temperature profiles as radiosonde, lidar or satellite. The main advantage of microwave radiometers against these other instruments is a high temporal resolution with a reasonable good spatial resolution. Moreover, the measurement at a fixed location allows to observe local atmospheric dynamics over a long time period, which is crucial for climate research. TEMPERA (TEMPERature RAdiometer) is a newly developed ground-based microwave radiometer designed, built and operated at the University of Bern. The instrument and the retrieval of temperature profiles has been described in detail in [2]. TEMPERA is measuring a pressure broadened oxygen line at 53.1 GHz in order to determine <span class="hlt">stratospheric</span> temperature profiles. The retrieved profiles of TEMPERA cover an altitude range of approximately 20 to 45 km with a vertical resolution in the order of 15 km. The lower limit is given by the instrumental baseline and the bandwidth of the measured spectrum. The upper limit is given by the fact that above 50 km the oxygen lines are splitted by the Zeeman effect in the terrestrial magnetic field. In this study we present a comparison of <span class="hlt">stratospheric</span></p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2004APS..APRL13003H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2004APS..APRL13003H"><span id="translatedtitle">Teaching Global <span class="hlt">Warming</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hobson, Art</p> <p>2004-05-01</p> <p>Every citizen's education should include socially relevant science courses because, as the American Association for the Advancement of Science puts it, "Without a scientifically literate population, the outlook for a better world is not promising." I have developed a conceptual liberal-arts physics course that covers the major principles of classical physics, emphasizes modern/contemporary physics, and includes societal topics such as global <span class="hlt">warming</span>, ozone depletion, transportation, exponential growth, scientific methodology, risk assessment, nuclear weapons, nuclear power, and the energy future. The societal topics, occupying only about 15% of the class time, appear to be the main cause of the surprising popularity of this course among non-scientists. I will outline some ideas for incorporating global <span class="hlt">warming</span> into such a course or into any other introductory physics course. For further details, see my textbook Physics: Concepts and Connections (Prentice Hall, 3rd edition 2003).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016cosp...41E.356C&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016cosp...41E.356C&link_type=ABSTRACT"><span id="translatedtitle"><span class="hlt">Stratospheric</span> experiments on curing of composite materials</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Chudinov, Viacheslav; Kondyurin, Alexey; Svistkov, Alexander L.; Efremov, Denis; Demin, Anton; Terpugov, Viktor; Rusakov, Sergey</p> <p>2016-07-01</p> <p>Future space exploration requires a large light-weight structure for habitats, greenhouses, space bases, space factories and other constructions. A new approach enabling large-size constructions in space relies on the use of the technology of polymerization of fiber-filled composites with a curable polymer matrix applied in the free space environment on Erath orbit. In orbit, the material is exposed to high vacuum, dramatic temperature changes, plasma of free space due to cosmic rays, sun irradiation and atomic oxygen (in low Earth orbit), micrometeorite fluence, electric charging and microgravitation. The development of appropriate polymer matrix composites requires an understanding of the chemical processes of polymer matrix curing under the specific free space conditions to be encountered. The goal of the <span class="hlt">stratospheric</span> flight experiment is an investigation of the effect of the <span class="hlt">stratospheric</span> conditions on the uncured polymer matrix of the composite material. The unique combination of low residual pressure, high intensity UV radiation including short-wave UV component, cosmic rays and other aspects associated with solar irradiation strongly influences the chemical processes in polymeric materials. We have done the <span class="hlt">stratospheric</span> flight experiments with uncured composites (prepreg). A balloon with payload equipped with heater, temperature/pressure/irradiation sensors, microprocessor, carrying the samples of uncured prepreg has been launched to <span class="hlt">stratosphere</span> of 25-30 km altitude. After the flight, the samples have been tested with FTIR, gel-fraction, tensile test and DMA. The effect of cosmic radiation has been observed. The composite was successfully cured during the <span class="hlt">stratospheric</span> flight. The study was supported by RFBR grants 12-08-00970 and 14-08-96011.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ars.usda.gov/research/publications/Publications.htm?seq_no_115=209721','TEKTRAN'); return false;" href="http://www.ars.usda.gov/research/publications/Publications.htm?seq_no_115=209721"><span id="translatedtitle">PERENNIAL <span class="hlt">WARM</span>-SEASON GRASSES</span></a></p> <p><a target="_blank" href="http://www.ars.usda.gov/services/TekTran.htm">Technology Transfer Automated Retrieval System (TEKTRAN)</a></p> <p></p> <p></p> <p><span class="hlt">Warm</span>-season grasses and can be used to augment the forage supply for grazing livestock operations in the northeastern U.S. Much of what is known about <span class="hlt">warm</span> season grass production and management in the northeastern US was obtained from a soil conservation or wildlife habitat perspective. <span class="hlt">Warm</span>-seas...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2010-title40-vol17/pdf/CFR-2010-title40-vol17-part82-subpartA-appI.pdf','CFR'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2010-title40-vol17/pdf/CFR-2010-title40-vol17-part82-subpartA-appI.pdf"><span id="translatedtitle">40 CFR Appendix I to Subpart A of... - Global <span class="hlt">Warming</span> Potentials (Mass Basis), Referenced to the Absolute GWP for the Adopted Carbon...</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2010&page.go=Go">Code of Federal Regulations, 2010 CFR</a></p> <p></p> <p>2010-07-01</p> <p>... Environment Programme (UNEP), February 1995, Scientific Assessment of Ozone Depletion: 1994, Chapter 13, “Ozone Depleting Potentials, Global <span class="hlt">Warming</span> Potentials and Future Chlorine/Bromine Loading,” and do not... PROGRAMS (CONTINUED) PROTECTION OF <span class="hlt">STRATOSPHERIC</span> OZONE Production and Consumption Controls Pt. 82, Subpt....</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2011-title40-vol17/pdf/CFR-2011-title40-vol17-part82-subpartA-appI.pdf','CFR2011'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2011-title40-vol17/pdf/CFR-2011-title40-vol17-part82-subpartA-appI.pdf"><span id="translatedtitle">40 CFR Appendix I to Subpart A of... - Global <span class="hlt">Warming</span> Potentials (Mass Basis), Referenced to the Absolute GWP for the Adopted Carbon...</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2011&page.go=Go">Code of Federal Regulations, 2011 CFR</a></p> <p></p> <p>2011-07-01</p> <p>... Environment Programme (UNEP), February 1995, Scientific Assessment of Ozone Depletion: 1994, Chapter 13, “Ozone Depleting Potentials, Global <span class="hlt">Warming</span> Potentials and Future Chlorine/Bromine Loading,” and do not... PROGRAMS (CONTINUED) PROTECTION OF <span class="hlt">STRATOSPHERIC</span> OZONE Production and Consumption Controls Pt. 82, Subpt....</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2012EGUGA..14.3397B&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2012EGUGA..14.3397B&link_type=ABSTRACT"><span id="translatedtitle">Global <span class="hlt">Warming</span> And Meltwater</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bratu, S.</p> <p>2012-04-01</p> <p>In order to find new approaches and new ideas for my students to appreciate the importance of science in their daily life, I proposed a theme for them to debate. They had to search for global <span class="hlt">warming</span> information and illustrations in the media, and discuss the articles they found in the classroom. This task inspired them to search for new information about this important and timely theme in science. I informed my students that all the best information about global <span class="hlt">warming</span> and meltwater they found would be used in a poster that would help us to update the knowledge base of the Physics laboratory. I guided them to choose the most eloquent images and significant information. Searching and working to create this poster, the students arrived to better appreciate the importance of science in their daily life and to critically evaluate scientific information transmitted via the media. In the poster we created, one can find images, photos and diagrams and some interesting information: Global <span class="hlt">warming</span> refers to the rising average temperature of the Earth's atmosphere and oceans and its projected evolution. In the last 100 years, the Earth's average surface temperature increased by about 0.8 °C with about two thirds of the increase occurring over just the last three decades. <span class="hlt">Warming</span> of the climate system is unequivocal, and scientists are more than 90% certain most of it is caused by increasing concentrations of greenhouse gases produced by human activities such as deforestation and burning fossil fuel. They indicate that during the 21st century the global surface temperature is likely to rise a further 1.1 to 2.9 °C for the lowest emissions scenario and 2.4 to 6.4 °C for the highest predictions. An increase in global temperature will cause sea levels to rise and will change the amount and pattern of precipitation, and potentially result in expansion of subtropical deserts. <span class="hlt">Warming</span> is expected to be strongest in the Arctic and would be associated with continuing decrease of</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19910042409&hterms=LIMS&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3DLIMS','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19910042409&hterms=LIMS&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3DLIMS"><span id="translatedtitle">LIMS (Limb Infrared Monitor of the <span class="hlt">Stratosphere</span>) observation of traveling planetary waves and potential vorticity advection in the <span class="hlt">stratosphere</span> and mesosphere</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Dunkerton, Timothy J.</p> <p>1991-01-01</p> <p>Eastward and westward traveling waves were observed by the Nimbus 7 Limb Infrared Monitor of the <span class="hlt">Stratosphere</span> (LIMS) during the northern winter 1978-1979. Eastward waves were prevalent in early winter and were involved in a minor Canadian <span class="hlt">warming</span> in December 1978. A large westward traveling wave, as described by previous authors, was observed in January 1979 during a series of minor <span class="hlt">warmings</span>. By comparing these two events, it is shown that in both cases the superposition of traveling and quasi-stationary waves led to constructive interference that was responsible for the <span class="hlt">warmings</span>. However, there was significant asymmetry between eastward and westward traveling components. A local Eulerian analysis of potential vorticity (PV) transport indicates that adiabatic, geostrophic advection by the resolvable scales of motion explains qualitatively (but not quantitatively) the observed potential vorticity tendencies in the LIMS Northern Hemisphere winter. In particular, calculated advection explains the eastward rotation of the main vortex, intrusion of low PV air into the polar cap, and formation of high PV filaments at the vortex periphery.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015PhDT.......297S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015PhDT.......297S"><span id="translatedtitle"><span class="hlt">Stratospheric</span> flight environmental impact: Analysis of trends and tradeoffs</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sheng, Hang</p> <p></p> <p>When jetliners fly in the <span class="hlt">stratosphere</span>, their emissions tend to be longer-lived and therefore have greater environmental impact. Since the bottom of the <span class="hlt">stratosphere</span> can be lower than the cruise altitude of most commercial flights, the amount of <span class="hlt">stratospheric</span> emissions must not be overlooked. The impacts of <span class="hlt">stratospheric</span> emissions are different from tropospheric emissions, and the amount of <span class="hlt">stratospheric</span> emissions today need to be evaluated. On the other hand, some studies suggest placing more flights into the <span class="hlt">stratosphere</span>, as flying in the <span class="hlt">stratosphere</span> can significantly reduce the presence of contrails. The tradeoff between the effect of contrails and that of <span class="hlt">stratospheric</span> emissions is still unclear, but contrails can often be avoided without entering the <span class="hlt">stratosphere</span>. In this study, we develop simple quantitative ways of assessing current <span class="hlt">stratospheric</span> fuel burn using publicly available data, and then we develop a way of assessing <span class="hlt">stratospheric</span> flight strategies. Our analysis covers 78% of the total travelled distance reported by the United States Bureau of Transportation Statistics, and shows that these flights burned ~ 9 million tons of fuel annually, or ~ 25% of cruise fuel, in the <span class="hlt">stratosphere</span> between 2008 and 2012. Our results also show that the chance of flying into <span class="hlt">stratosphere</span> varies by area because of variations in the tropopause height, but flights within the contiguous United States tend to stay below the <span class="hlt">stratosphere</span>. The <span class="hlt">stratosphere</span> fuel burn of Asia-US flights may be significantly reduced by taking jet stream routes since the <span class="hlt">stratosphere</span> is lower near the poles. For the feasibility of contrail avoidance, our result showed that the chance of finding an Ice-Supersaturated-free region within 1000 ft. of the current flight level below the tropopause is significant for mid-latitude regions. We also found that if the region right below the tropopause is occupied by an Ice-Supersaturated Region (ISSR), this ISSR tends to be thicker. Thus, if a flight in</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/7297740','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/7297740"><span id="translatedtitle">Revelations of a <span class="hlt">stratospheric</span> circulation: The dynamical transport of hydrocarbons in the <span class="hlt">stratosphere</span> of Uranus</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>McMillan, W.W.</p> <p>1992-01-01</p> <p>Observations by the Ultraviolet Spectrometer (UVS) onboard the Voyager 2 spacecraft revealed that above the 1 mb level, the mixing ratios of CH[sub 4], C[sub 2]H[sub 2], and C[sub 2]H[sub 6] are at least 10-100 times larger at the equator than at the south pole. In addition, the Voyager 2 Infrared Interferometric Spectrometer (IRIS) measured small meridional temperature gradients at the tropopause (60-200 mb) and in the upper troposphere (200-1000 mb) of Uranus. These temperature gradients result from a weak meridional circulation in the Uranian troposphere which penetrates into the <span class="hlt">stratosphere</span> with upwelling at low southern latitudes and polar subsidence (vertical velocities [approximately]10[sup [minus]6] m/s, meridional velocities [approximately]10[sup [minus]3] m/s). The role of the zonally-averaged, meridional <span class="hlt">stratospheric</span> circulation in determining the distribution of hydrocarbons in the <span class="hlt">stratosphere</span> (0.1-100 mb) of Uranus is investigated with a 2-dimensional photochemical transport model. The <span class="hlt">stratospheric</span> circulation is calculated with a linear, zonally-symmetric model with Newtonian cooling and Rayleigh friction similar to that used by Flaser et al. (1987). Operator-splitting is utilized to numerically solve the continuity equations for trace species in the <span class="hlt">stratosphere</span> of Uranus. It is determined that advective transport by the <span class="hlt">stratospheric</span> circulation can account for the essential observed meridional variation of <span class="hlt">stratospheric</span> hydrocarbon abundances. However, vertical transport by eddy and molecular diffusion is required to fit the inferred vertical distribution of hydrocarbons. The uniform eddy diffusion coefficient is constrained to 10 cm[sup 2]/s < K < 100 cm[sup 2]/s (i.e. constant in both altitude and latitude). The best fit model has a meridional circulation three times stronger than the circulation of Flaser et al. and a weak uniform eddy diffusion coefficient, K = 100 cm[sup 2]/s.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/6823689','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/6823689"><span id="translatedtitle">Global <span class="hlt">warming</span> - A reduced threat</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Michaels, P.J.; Stooksbury, D.E. )</p> <p>1992-10-01</p> <p>Issues associated with global <span class="hlt">warming</span> are analyzed focusing on global and hemispheric temperature histories and trace gas concentrations; artificial <span class="hlt">warming</span> from urban heat islands; high-latitude and diurnal temperatures; recent climate models; direct effects on vegetation of an increase in carbon dioxide; and compensatory cooling from other industrial products. Data obtained indicate that anthropogenerated sulfate emissions are mitigating some of the <span class="hlt">warming</span>, and that increased cloudiness as a result of these emissions will further enhance night, rather than day, <span class="hlt">warming</span>. It is noted that the sulfate emissions are not sufficient to explain all of the night <span class="hlt">warming</span>. The sensitivity of climate to anthropogenerated aerosols, and the general lack of previously predicted <span class="hlt">warming</span>, could drastically alter the debate on global <span class="hlt">warming</span> in favor of less expensive policies. 61 refs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20080023301&hterms=warming&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dwarming','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20080023301&hterms=warming&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dwarming"><span id="translatedtitle">The Evolution of the Stratopause during the 2006 Major <span class="hlt">Warming</span>: Satellite Data and Assimilated Meteorological Analyses</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Manney, Gloria L.; Krueger, Kirstin; Pawson, Steven; Minschwaner, Ken; Schwartz, Michael J.; Daffer, William H.; Livesey, Nathaniel J.; Mlynczak, Martin G.; Remsberg, Ellis E.; Russell, James M., III; Waters, Joe W.</p> <p>2008-01-01</p> <p>Microwave Limb Sounder and Sounding of the Atmosphere with Broadband Emission Radiometry data provide the first opportunity to characterize the four-dimensional stratopause evolution throughout the life-cycle of a major <span class="hlt">stratospheric</span> sudden <span class="hlt">warming</span> (SSW). The polar stratopause, usually higher than that at midlatitudes, dropped by 30 km and <span class="hlt">warmed</span> during development of a major "wave 1" SSW in January 2006, with accompanying mesospheric cooling. When the polar vortex broke down, the stratopause cooled and became ill-defined, with a nearly isothermal <span class="hlt">stratosphere</span>. After the polar vortex started to recover in the upper <span class="hlt">stratosphere</span>/lower mesosphere (USLM), a cool stratopause reformed above 75 km, then dropped and <span class="hlt">warmed</span>; both the mesosphere above and the <span class="hlt">stratosphere</span> below cooled at this time. The polar stratopause remained separated from that at midlatitudes across the core of the polar night jet. In the early stages of the SSW, the strongly tilted (westward with increasing altitude) polar vortex extended into the mesosphere, and enclosed a secondary temperature maximum extending westward and slightly equatorward from the highest altitude part of the polar stratopause over the cool stratopause near the vortex edge. The temperature evolution in the USLM resulted in strongly enhanced radiative cooling in the mesosphere during the recovery from the SSW, but significantly reduced radiative cooling in the upper <span class="hlt">stratosphere</span>. Assimilated meteorological analyses from the European Centre for Medium-Range weather Forecasts (ECMWF) and Goddard Earth Observing System Version 5.0.1 (GEOS-5), which are not constrained by data at polar stratopause altitudes and have model tops near 80 km, could not capture the secondary temperature maximum or the high stratopause after the SSW; they also misrepresent polar temperature structure during and after the stratopause breakdown, leading to large biases in their radiative heating rates. ECMWF analyses represent the <span class="hlt">stratospheric</span> temperature</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1997hst..prop.7961C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1997hst..prop.7961C"><span id="translatedtitle">FLATs: <span class="hlt">Warming</span> Up</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Calzetti, Daniela</p> <p>1997-07-01</p> <p>The purpose of this proposal is to monitor the flat fields during the interval between the end of science observations and the exhaustion of cryogen and subsequent <span class="hlt">warming</span> of the dewar to > 100K. These flats will provide a monitor for particulate comtamination {GROT} and detector lateral position {from the coronagraphic spot and FDA vignetting}. They will provide some measure of relative {flat field} and absolute QE variation as a function of temperature. When stars are visible they might provide a limited degree of focus determination.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1997hst..prop.8083C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1997hst..prop.8083C"><span id="translatedtitle">FLATs: <span class="hlt">Warming</span> Up - continuation</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Calzetti, Daniela</p> <p>1997-07-01</p> <p>The purpose of this proposal is to monitor the flat fields during the interval between the end of science observations and the exhaustion of cryogen and subsequent <span class="hlt">warming</span> of the dewar to > 100K. These flats will provide a monitor for particulate comtamination {GROT} and detector lateral position {from the coronagraphic spot and FDA vignetting}. They will provide some measure of relative {flat field} and absolute QE variation as a function of temperature. When stars are visible they might provide a limited degree of focus determination.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20120011786','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20120011786"><span id="translatedtitle">Long-Term Changes in <span class="hlt">Stratospheric</span> Age Spectra in the 21st Century in the Goddard Earth Observing System Chemistry-Climate Model (GEOSCCM)</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Li, Feng; Waugh, Darryn W.; Douglass, Anne R.; Newman, Paul A.; Strahan, Susan E.; Ma, Jun; Nielsen, J. Eric; Liang, Qing</p> <p>2012-01-01</p> <p>In this study we investigate the long-term variations in the <span class="hlt">stratospheric</span> age spectra using simulations of the 21st century with the Goddard Earth Observing System Chemistry- Climate Model (GEOSCCM). Our purposes are to characterize the long-term changes in the age spectra and identify processes that cause the decrease of the mean age in a <span class="hlt">warming</span> climate. Changes in the age spectra in the 21st century simulations are characterized by decreases in the modal age, the mean age, the spectral width, and the tail decay timescale. Our analyses show that the decrease in the mean age is caused by two processes: the acceleration of the residual circulation that increases the young air masses in the <span class="hlt">stratosphere</span>, and the weakening of the recirculation that leads to the decrease of tail of the age spectra and the decrease of the old air masses. The weakening of the <span class="hlt">stratospheric</span> recirculation is also strongly correlated with the increase of the residual circulation. One important result of this study is that the decrease of the tail of the age spectra makes an important contribution to the decrease of the main age. Long-term changes in the <span class="hlt">stratospheric</span> isentropic mixing are investigated. Mixing increases in the subtropical lower <span class="hlt">stratosphere</span>, but its impact on the age spectra is outweighed by the increase of the residual circulation. The impacts of the long-term changes in the age spectra on long-lived chemical traces are also investigated. 37 2</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009PhDT.......130H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009PhDT.......130H"><span id="translatedtitle">Retrieval of <span class="hlt">stratospheric</span> ozone and nitrogen dioxide profiles from Odin Optical Spectrograph and Infrared Imager System (OSIRIS) limb-scattered sunlight measurements</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Haley, Craig Stuart</p> <p>2009-12-01</p> <p>Key to understanding and predicting the effects of global environmental problems such as ozone depletion and global <span class="hlt">warming</span> is a detailed understanding of the atmospheric processes, both dynamical and chemical. Essential to this understanding are accurate global data sets of atmospheric constituents with adequate temporal and spatial (vertical and horizontal) resolutions. For this purpose the Canadian satellite instrument OSIRIS (Optical Spectrograph and Infrared Imager System) was launched on the Odin satellite in 2001. OSIRIS is primarily designed to measure minor <span class="hlt">stratospheric</span> constituents, including ozone (O3) and nitrogen dioxide (NO2), employing the novel limb-scattered sunlight technique, which can provide both good vertical resolution and near global coverage. This dissertation presents a method to retrieve <span class="hlt">stratospheric</span> O 3 and NO2 from the OSIRIS limb-scatter observations. The retrieval method incorporates an a posteriori optimal estimator combined with an intermediate spectral analysis, specifically differential optical absorption spectroscopy (DOAS). A detailed description of the retrieval method is presented along with the results of a thorough error analysis and a geophysical validation exercise. It is shown that OSIRIS limb-scatter observations successfully produce accurate <span class="hlt">stratospheric</span> O3 and NO2 number density profiles throughout the <span class="hlt">stratosphere</span>, clearly demonstrating the strength of the limb-scatter technique. The OSIRIS observations provide an extremely useful data set that is of particular importance for studies of the chemistry of the middle atmosphere. The long OSIRIS record of <span class="hlt">stratospheric</span> ozone and nitrogen dioxide may also prove useful for investigating variability and trends.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1985maph...15...90W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1985maph...15...90W"><span id="translatedtitle">Microwave limb sounder for <span class="hlt">stratospheric</span> measurements</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Waters, J. W.; Hardy, J. C.; Jarnot, R. F.; Pickett, H. M.; Zimmerman, P.</p> <p>1985-06-01</p> <p>The balloon-borne Microwave Limb Sounder (BMLS) measures atmospheric thermal emission from millimeter wavelength spectral lines to determine vertical profiles of <span class="hlt">stratospheric</span> species. The instrument flown to data operates at 205 BHz to measure ClO, O3, and H2O2. A 63 GHz radiometer is added to test the technique for determining tangent point pressure from the MLS experiment on the Upper Atmosphere Research Satellite (UARS). Many additional species is also measured by the BLMS. A radiometer at 270 GHz would provide measurements of HO2, NO2, HNO3, N2O, 16O18O16O, and HCN. With this addition the BMLS can test the current theory of O3 heavy ozone photochemical balance in the upper <span class="hlt">stratosphere</span>.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li class="active"><span>24</span></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_24 --> <div id="page_25" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li class="active"><span>25</span></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="481"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20120001837','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20120001837"><span id="translatedtitle">Pristine <span class="hlt">Stratospheric</span> Collections of Cosmic Dust</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Messenger, S.; Keller, L. P.; Nakamura-Messenger, K.; Clemett, S. J.</p> <p>2012-01-01</p> <p>Since 1981, NASA has routinely collected interplanetary dust particles (IDPs) in the <span class="hlt">stratosphere</span> by inertial impact onto silicone oil-coated flat plate collectors deployed on the wings of high-altitude aircraft [1]. The highly viscous oil traps and localizes the particles, which can fragment during collection. Particles are removed from the collectors with a micromanipulator and washed of the oil using organic solvents, typically hexane or xylene. While silicone oil is an efficient collection medium, its use is problematic. All IDPs are initially coated with this material (polydimethylsiloxane, n(CH3)2SiO) and traces of oil may remain after cleaning. The solvent rinse itself is also a concern as it likely removes indigenous organics from the particles. To avoid these issues, we used a polyurethane foam substrate for the oil-free <span class="hlt">stratospheric</span> collection of IDPs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20010037601','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20010037601"><span id="translatedtitle">Modeling Nitrogen Oxides in the Lower <span class="hlt">Stratosphere</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Kawa, S. Randy; Einaudi, Franco (Technical Monitor)</p> <p>2001-01-01</p> <p>This talk will focus on the status of current understanding (not a historical review) as regards modeling nitrogen oxides (NOy) in the lower <span class="hlt">stratosphere</span> (LS). The presentation will be organized around three major areas of process understanding: 1) NOy sources, sinks, and transport to the LS, 2) NOy species partitioning, and 3) polar multiphase processes. In each area, process topics will be identified with an estimate of the degree of confidence associated with their representation in numerical models. Several exotic and/or speculative processes will also be discussed. Those topics associated with low confidence or knowledge gaps, weighted by their prospective importance in <span class="hlt">stratospheric</span> chemical modeling, will be collected into recommendations for further study. Suggested approaches to further study will be presented for discussion.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19850035855&hterms=Hydrogen+peroxide&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3D%2528Hydrogen%2Bperoxide%2529','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19850035855&hterms=Hydrogen+peroxide&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3D%2528Hydrogen%2Bperoxide%2529"><span id="translatedtitle">An upper limit for <span class="hlt">stratospheric</span> hydrogen peroxide</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Chance, K. V.; Traub, W. A.</p> <p>1984-01-01</p> <p>It has