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Sample records for stratospheric warmings ssws

  1. Comparing Sudden Stratospheric Warming Definitions in Reanalysis Data

    NASA Astrophysics Data System (ADS)

    Palmeiro, Froila M.; Barriopedro, David; García-Herrera, Ricardo; Calvo, Natalia

    2015-04-01

    Sudden Stratospheric Warmings (SSWs) are the main source of variability in the northern hemisphere polar stratosphere during winter. They are characterized by a dramatic warming of the polar stratosphere and weakening of the polar vortex circulation. SSWs can have an impact on surface weather, which makes them a potential tool for seasonal prediction. However, there is no consensus on the definition of SSWs, and multiple methods exist in the literature, yielding discrepancies on the detected events. In this presentation we compare the SSWs signatures of eight representative definitions for the 1958-2009 period and using three different reanalysis data (ERA, NCEP and JRA). The monthly distribution of SSWs is indistinguishable across definitions, with a common peak in January. However, the multi-decadal variability is method-dependent, with only three definitions displaying minimum frequencies in the 1990s. Comparison of several SSW benchmarks reveals negligible differences among methods due to the large case-to-case variability of events within a given definition. In the troposphere, the most robust signals across definitions before and after events are dominated by major SSWs, which are detected by most methods. Interestingly, minor SSWs represent the largest source of discrepancy in the surface signals of SSWs across definitions. Therefore, our results indicate that only major SSWs should be considered in future studies if robust tropospheric signals of SSWs want to be obtained regardless of the chosen method.

  2. A sudden stratospheric warming compendium

    NASA Astrophysics Data System (ADS)

    Butler, Amy H.; Sjoberg, Jeremiah P.; Seidel, Dian J.; Rosenlof, Karen H.

    2017-02-01

    Major, sudden midwinter stratospheric warmings (SSWs) are large and rapid temperature increases in the winter polar stratosphere are associated with a complete reversal of the climatological westerly winds (i.e., the polar vortex). These extreme events can have substantial impacts on winter surface climate, including increased frequency of cold air outbreaks over North America and Eurasia and anomalous warming over Greenland and eastern Canada. Here we present a SSW Compendium (SSWC), a new database that documents the evolution of the stratosphere, troposphere, and surface conditions 60 days prior to and after SSWs for the period 1958-2014. The SSWC comprises data from six different reanalysis products: MERRA2 (1980-2014), JRA-55 (1958-2014), ERA-interim (1979-2014), ERA-40 (1958-2002), NOAA20CRv2c (1958-2011), and NCEP-NCAR I (1958-2014). Global gridded daily anomaly fields, full fields, and derived products are provided for each SSW event. The compendium will allow users to examine the structure and evolution of individual SSWs, and the variability among events and among reanalysis products. The SSWC is archived and maintained by NOAA's National Centers for Environmental Information (NCEI, doi:10.7289/V5NS0RWP).

  3. 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.

  4. 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.

  5. Do split and displacement sudden stratospheric warmings have different annular mode signatures?

    NASA Astrophysics Data System (ADS)

    Maycock, Amanda C.; Hitchcock, Peter

    2015-12-01

    Sudden stratospheric warmings (SSWs) contribute to intraseasonal tropospheric forecasting skill due to their surface impacts. Recent studies suggest these impacts depend upon whether the polar vortex splits or is displaced during the SSW. We analyze the annular mode signatures of SSWs in a 1000 year IPSL-CM5A-LR simulation. Although small differences in the mean surface Northern Annular Mode (NAM) index following splits and displacements are found, the sign is not consistent for two independent SSW algorithms, and over 50 events are required to distinguish the responses. We use the wintertime correlation between extratropical lower stratospheric wind anomalies and the surface NAM index as a metric for two-way stratosphere-troposphere coupling and find that the differences between splits and displacements, and between classification methodologies, can be simply understood in terms of their mean stratospheric wind anomalies. Predictability studies should therefore focus on understanding the factors that determine the persistence of these anomalies following SSWs.

  6. Do split and displacement sudden stratospheric warmings have different annular mode signatures?

    NASA Astrophysics Data System (ADS)

    Maycock, Amanda; Hitchcock, Peter

    2016-04-01

    Sudden stratospheric warmings (SSWs) contribute to intraseasonal tropospheric forecasting skill due to their surface impacts. Recent studies suggest these impacts depend upon whether the polar vortex splits or is displaced during the SSW. We analyse the annular mode signatures of SSWs in a 1000 year IPSL-CM5A-LR simulation. Although small differences in the mean surface Northern Annular Mode (NAM) index following splits and displacements are found, the sign is not consistent for two independent SSW algorithms, and over 50 events are required to distinguish the responses. We use the winter-time correlation between extratropical lower stratospheric wind anomalies and the surface NAM index as a metric for two-way stratosphere-troposphere coupling, and find that the differences between splits and displacements, and between classification methodologies, can be simply understood in terms of their mean stratospheric wind anomalies. Predictability studies should therefore focus on understanding the factors that determine the persistence of these anomalies following SSWs.

  7. Role of Stratospheric Sudden Warmings on the response to Central Pacific El Niño

    NASA Astrophysics Data System (ADS)

    Iza, Maddalen; Calvo, Natalia

    2015-04-01

    The Northern Hemisphere (NH) polar stratospheric response to Central Pacific El Niño (CP-El Niño) events remains unclear. Contradictory results have been reported depending on the definition and events considered. We show that this is due to the prominent role of Stratospheric Sudden Warmings (SSWs), whose signal dominates the NH winter polar stratospheric response to CP-El Niño. In fact, the CP-El Niño signal is robust when the events are classified according to the occurrence of SSWs and displays opposite response in winters with and without SSWs. In the absence of SSWs, polar stratospheric responses to Central Pacific and Eastern Pacific El Niño are clearly distinguishable in early winter, in relation to differences in the Pacific-North American pattern. Our results demonstrate that the occurrence of SSWs needs to be taken into account when studying the stratospheric response to CP-El Niño and explain why different responses to CP-El Niño have been reported previously.

  8. 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.

  9. Properties of stratospheric warming events during northern winter.

    NASA Astrophysics Data System (ADS)

    Maury, Pauline; Claud, Chantal; Manzini, Elisa; Hauchecorne, Alain; Keckhut, Philippe

    2015-04-01

    During wintertime the polar mid-stratosphere is characterized by the setting up of westerly winds around the pole; the so-called polar vortex. The polar vortex is one of the most variable features of the zonal-mean circulation of the earth atmosphere, due to a highly non linear interaction between planetary-scale Rossby waves and the zonal flow. Indeed, the interaction between the upward tropospheric propagating waves and the polar vortex leads to a zonal flow weakening, implying a large day to day vortex variability. In the most dramatic cases the polar vortex breaks down, the stratospheric polar flow can reverse its direction and the temperatures can rise locally by more than 50K in a span of a few days. Such phenomena are known as Sudden Stratospheric Warmings (SSWs) and constitute, since their discovery, the most impressive dynamical events in the physical climate system. There are however situations where the polar vortex does not break down, but temperatures increase dramatically. In this study, we propose a global characterization of stratospheric warmings situations based on a temperature threshold in the 50-10hPa layer, in order to assess the properties of daily stratospheric temperature variability during the northern winter. The originality of this approch consists in evaluating the wintertime positive temperature anomalies in terms of intensity and duration. We will show that there is a wide spectrum of warming types. The major SSWs are the most extreme, but there are other events that share some common properties with the major ones. Though neglected, these latter warmings may play a key role in the coupling of the stratosphere-troposphere system.

  10. Poleward transport variability in the Northern Hemisphere during final stratospheric warmings simulated by CESM(WACCM)

    NASA Astrophysics Data System (ADS)

    Thiéblemont, Rémi; Matthes, Katja; Orsolini, Yvan J.; Hauchecorne, Alain; Huret, Nathalie

    2016-09-01

    Observational studies of Arctic stratospheric final warmings have shown that tropical/subtropical air masses can be advected to high latitudes and remain confined within a long-lived "frozen-in" anticyclone (FrIAC) for several months. It was suggested that the frequency of FrIACs may have increased since 2000 and that their interannual variability may be modulated by (i) the occurrence of major stratospheric warmings (mSSWs) in the preceding winter and (ii) the phase of the quasi-biennial oscillation (QBO). In this study, we tested these observational-based hypotheses for the first time using a chemistry climate model. Three 145 year sensitivity experiments were performed with the National Center of Atmospheric Research's Community Earth System Model (CESM): one control experiment including only natural variability, one with an extreme greenhouse gas emission scenario, and one without the QBO in the tropical stratosphere. In comparison with reanalysis, the model simulates a realistic frequency and characteristics of FrIACs, which occur under an abrupt and early winter-to-summer stratospheric circulation transition, driven by enhanced planetary wave activity. Furthermore, the model results support the suggestion that the development of FrIACs is favored by an easterly QBO in the middle stratosphere and by the absence of mSSWs during the preceding winter. The lower stratospheric persistence of background dynamical state anomalies induced by deep mSSWs leads to less favorable conditions for planetary waves to enter the high-latitude stratosphere in April, which in turn decreases the probability of FrIAC development. Our model results do not suggest that climate change conditions (RCP8.5 scenario) influence FrIAC occurrences.

  11. 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.

  12. 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.

  13. Lunar tide in the equatorial electrojet in relation to stratospheric warmings

    NASA Astrophysics Data System (ADS)

    Stening, R. J.

    2011-12-01

    The relationship between sudden stratospheric warmings (SSWs) and large-amplitude lunar tides in the equatorial electrojet (EEJ) is studied. Analysis of ground magnetometer data shows that the lunar tide in the EEJ is maximum during the northern winter season except in the Pacific Ocean region. Since SSWs are also a northern winter phenomenon, it is suggested that the relation between the large lunar tide in the EEJ and the SSW may possibly be coincidental. The lunar tide in the geomagnetic variations at Huancayo is anomalously large compared with other EEJ stations. An examination of geomagnetic variations at EEJ stations during SSW events shows that afternoon counter-electrojets are frequently present at new moon and full moon, though the relationship is sometimes broken. The observation of large lunar EEJs when no SSW is present and of various different delay times suggests that other atmospheric processes are likely to be in play.

  14. 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.

  15. Modeling of the effect of internal gravity waves on upper atmospheric conditions during sudden stratospheric warming

    NASA Astrophysics Data System (ADS)

    Vasilyev, Pavel; Karpov, Ivan; Kshevetskiy, Sergey

    2016-09-01

    We present results of modeling of the effect of internal gravity waves (IGW), excited in the region of the development of a sudden stratospheric warming (SSW), on upper atmospheric conditions. In the numerical experiment, we use a two-dimensional model of propagation of atmospheric waves, taking into account dissipative and nonlinear processes accompanying wave propagation. As a source of disturbances, we consider temperature and density disturbances in the stratosphere during SSWs. Amplitude and frequency characteristics of the source of disturbances are estimated from observations and IGW theory. Numerical calculations showed that waves generated at stratospheric heights during SSW can cause temperature changes in the upper atmosphere. Maximum relative disturbances, generated by such waves, with respect to quiet conditions are observed at 100-200 km. Disturbances of the upper atmosphere in turn have an effect on dynamics of a charged component in the ionosphere and can contribute to observable ionospheric effects of SSW.

  16. Impact of semidiurnal tidal variability during SSWs on the mean state of the ionosphere and thermosphere

    NASA Astrophysics Data System (ADS)

    Pedatella, N. M.; Richmond, A. D.; Maute, A.; Liu, H.-L.

    2016-08-01

    Observations from the Constellation Observing System for Meteorology, Ionosphere, and Climate (COSMIC) satellites reveal a global reduction in the zonal and diurnal mean F region peak electron density (NmF2) during sudden stratosphere warmings (SSWs). The present study investigates the source of the global NmF2 decrease by performing numerical experiments with the National Center for Atmospheric Research (NCAR) thermosphere-ionosphere-electrodynamics general circulation model. The simulations reveal that the NmF2 reduction coincides with a depletion of thermospheric [O]/[N2], indicating that the NmF2 depletion is related to changes in thermospheric composition during SSWs. Numerical experiments further illustrate that the short-term (˜10 day) enhancement of the migrating semidiurnal solar tide (SW2) during SSWs is the source of the variability in thermospheric composition. In particular, the enhancement of the SW2 during SSWs alters the lower thermosphere zonal mean circulation, leading to a reduction in atomic oxygen in the lower thermosphere. The atomic oxygen reduction propagates into the upper thermosphere through molecular diffusion, leading to a decrease in [O]/[N2] throughout the low- to middle-latitude thermosphere. It is anticipated that the effects of the SW2 on the ionosphere and thermosphere investigated herein will be modulated by SSW related enhancements of the migrating semidiurnal lunar tide (M2). The magnitude of the combined impact of the SW2 and M2 on the ionosphere-thermosphere mean state will depend on the relative phasing of the solar and lunar tides. The results demonstrate that in addition to modulating the low-latitude electrodynamics, tidal variability during SSWs can significantly impact the mean state of the ionosphere and thermosphere.

  17. 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

  18. 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.

  19. Signatures of the Sudden Stratospheric Warming events of January-February 2008 in Seoul, S. Korea

    NASA Astrophysics Data System (ADS)

    De Wachter, Evelyn; Hocke, Klemens; Flury, Thomas; Scheiben, Dominik; Kämpfer, Niklaus; Ka, Soohyun; Oh, Jung Jin

    2011-11-01

    The period January-February 2008 was characterized by four Sudden Stratospheric Warmings (SSWs) in the Northern Hemisphere, of which the last warming, at the end of February 2008, was a major warming. A significant decrease in mesospheric water vapour (H 2O) of more than 2 ppmv (˜40%) was observed by the ground-based microwave (GBMW) radiometer in Seoul, S. Korea [37.3°N, 126.3°E] during the major SSW. A comparison with ground-based mesospheric H 2O observations from the mid-latitude station in Bern [46.9°N, 7°E] revealed an anticorrelation in the mesospheric H 2O data during the major SSW. In addition, prior to the major warming, strong periodic fluctuations were recorded in the Aura MLS vertical temperature distribution between 15 and 0.05 hPa at Seoul. The mesospheric temperature oscillation was found to have a period of ˜10-14 days with a persistency of 3-4 cycles. The observed anticorrelation in mesospheric H 2O between the stations in Seoul and Bern is associated with an increased meridional flow. Trajectory calculations give evidence that H 2O-rich subtropical air had moved to Bern during the major SSW while H 2O-poor polar air was transported to Seoul. The results shown in this study are a possible indication of a strong coupling between the dynamic regimes of the low- and the high-latitude regions during SSWs.

  20. The winter anomaly and sudden stratospheric warmings

    NASA Astrophysics Data System (ADS)

    Lastovicka, J.

    1984-08-01

    Large-scale stratospheric warmings are examined on the basis of 22-year measurements of radio-wave absorption at the Panska Ves observatory. It is shown that these warmings, accompanied by the reversal of wind direction in the lower thermosphere, lead not to an increase but to a decrease in the radio-wave absorption in the lower ionosphere, i.e., to the disappearance of the winter anomaly. It is concluded that the absorption decrease is connected not only with cooling in the mesopause region but also with a total change in the dynamic conditions of the lower ionosphere. The behavior of the winter anomaly in the 1979-1980 and 1981-1982 periods is examined in detail.

  1. Composite analysis of the temporal development of waves in the polar MLT region during stratospheric warmings

    NASA Astrophysics Data System (ADS)

    Matthias, Vivien; Hoffmann, Peter; Rapp, Markus; Baumgarten, Gerd

    2012-12-01

    During winter the wind field in the mesosphere/lower thermosphere (MLT) at middle and polar latitudes is characterized by a strong variability due to enhanced planetary wave activity and related stratospheric sudden warming (SSW) events. Such events are considered as distinct vertical coupling processes influencing the atmosphere below and above the stratosphere. In the last 12 years, an enhanced number of SSW, compared to the period from 1989 to 1998, has been observed in the northern hemisphere. Every SSW is connected with different effects in the MLT (strength and temporal development of wind reversals, temperature changes, wave activity, longitudinal dependence). To characterize the average behavior of the mesospheric response to strong SSWs, we combine high-resolution wind measurements from MF- and meteor radar at Andenes (69°N, 16°E) with global temperature observations from MLS aboard the Aura satellite for SSW events with a return to the middle atmosphere normal winter condition afterwards. Our aim is to identify characteristic wave patterns which are common to the majority of these events and to define the average characteristics of the SSW-related wave activity in the MLT. These will be compared to the relatively quiet winter 2011 with only a short minor warming without a wind reversal and to the wave activity in 2009 and 2010. The results show clear signatures of enhanced mesospheric planetary wave activity before and during the SSW and an earlier onset of the short term wind reversal in the mesosphere compared to wind and temperature changes in the stratosphere. The strong eastward winds at altitudes below 80 km after SSW are connected with an enhanced gravity wave activity caused by changed filter conditions. This provides evidence for a strong modulation of semidiurnal tidal amplitudes before and during SSW by planetary waves. However, no clear relation has been found in the temporal development of tides relative to the onset of the selected SSW

  2. 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.

  3. 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.

  4. 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.

  5. The Hiccup: a dynamical coupling process during the autumn transition in the Northern Hemisphere - similarities and differences to sudden stratospheric warmings

    NASA Astrophysics Data System (ADS)

    Matthias, V.; Shepherd, T. G.; Hoffmann, P.; Rapp, M.

    2015-02-01

    Sudden stratospheric warmings (SSWs) are the most prominent vertical coupling process in the middle atmosphere, which occur during winter and are caused by the interaction of planetary waves (PWs) with the zonal mean flow. Vertical coupling has also been identified during the equinox transitions, and is similarly associated with PWs. We argue that there is a characteristic aspect of the autumn transition in northern high latitudes, which we call the "hiccup", and which acts like a "mini SSW", i.e. like a small minor warming. We study the average characteristics of the hiccup based on a superimposed epoch analysis using a nudged version of the Canadian Middle Atmosphere Model, representing 30 years of historical data. Hiccups can be identified in about half the years studied. The mesospheric zonal wind results are compared to radar observations over Andenes (69° N, 16° E) for the years 2000-2013. A comparison of the average characteristics of hiccups and SSWs shows both similarities and differences between the two vertical coupling processes.

  6. Models of warm and cold regimes of the winter stratosphere

    NASA Astrophysics Data System (ADS)

    Guryanov, Vladimir

    Research of fields of geopotential height, temperature, zonal and meridional wind in stratosphere was carried out using the Met Office data for winter seasons from 1991/1992 to 2006-2007. The above analyzes shows that change within season thermodynamic values at high latitudes during the winter is higher than seasonal or longitudinal change. Hence the average models of the cold periods of high latitudes and average monthly values have a limited applicability. In 1982 International Standard Organization (ISO) also acknowledged the necessity for creating of special models for "warm" and "cold" regimes of the high latitude winter stratosphere. Warm and cold stratosphere states were distinguished by the presence or absence of stratospheric warmings of variable intensity exceeding 10 hPa. Special maps and latitude-longitude cuts of mean values and mean square deviations of the geopotential height, temperature, zonal and meridional wind have been created for these regimes. Models of "warm" and "cold" regimes also included zonal harmonics with wave numbers 1 and 2 for all observed meteorological fields

  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. Characterizing Middle Atmospheric Dynamical Variability and its Impact on the Thermosphere/Ionosphere System During Recent Stratospheric Sudden Warmings

    NASA Astrophysics Data System (ADS)

    McCormack, J. P.; Sassi, F.; Hoppel, K.; Ma, J.; Eckermann, S. D.

    2015-12-01

    We investigate the evolution of neutral atmospheric dynamics in the 10-100 km altitude range before, during, and after recent stratospheric sudden warmings (SSWs) using a prototype high-altitude version of the Navy Global Environmental Model (NAVGEM), which combines a 4-dimensional variational (4DVAR) data assimilation system with a 3-time-level semi-Lagrangian semi-implicit global forecast model. In addition to assimilating conventional meteorological observations, NAVGEM also assimilates middle atmospheric temperature and constituent observations from both operational and research satellite platforms to provide global synoptic meteorological analyses of winds, temperatures, ozone, and water vapor from the surface to ~90 km. In this study, NAVGEM analyses are used to diagnose the spatial and temporal evolution of the main dynamical drivers in the mesosphere and lower thermosphere (MLT) before, during, and after specific SSW events during the 2009-2013 period when large disturbances were observed in the thermosphere/ionosphere (TI) region. Preliminary findings show strong modulation of the semidiurnal tide in the MLT during the onset of an SSW. To assess the impact of the neutral atmosphere dynamical variability on the TI system, NAVGEM analyses are used to constrain simulations of select SSW events using the specified dynamics (SD) configuration of the extended Whole Atmosphere Community Climate Model (WACCM-X).

  11. 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.

  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. Semi diurnal lunar tides in the MLT at mid and high northern and southern latitudes during major sudden stratospheric warming events

    NASA Astrophysics Data System (ADS)

    Chau, J. L.; Hoffmann, P.; Pedatella, N. M.; Janches, D.; Murphy, D. J.; Stober, G.

    2015-12-01

    From recent ground- and satellite-based observations as well as from model results, it is well known that lunar tide signatures are amplified significantly during northern hemisphere sudden stratospheric warming events (SSWs). Such signatures have been observed in the equatorial and low latitude ionosphere and mesosphere, and at the mesosphere and lower thermosphere (MLT) at the northern mid and high latitude mesosphere. More recently, ionospheric signatures at mid-latitudes have been also observed in satellite instruments and such observations are corroborated with model results when the lunar tides are included. From these results (N. Pedatella, personal communication), there is a strong hemispheric asymmetry, where ionospheric perturbations occur primarily in the southern hemisphere. Motivated by these results, in this work we compare the tidal signatures in the MLT region at mid and high latitudes in both hemispheres. We make use of MLT winds obtained with specular meteor radars (SMR) at Juliusruh (54oN), Andøya (69oN), Rio Grande (54oS), and Davis (69oS) around the 2009 and 2013 major SSWs. In addition we complement our studies, with model results from the Whole Atmosphere Community Climate Model Extended version (WACCM-X) combined with the thermosphere-ionosphere-mesosphere electrodynamics general circulation model (TIME-GCM) and the inclusions of lunar tides. Besides these results, we present a brief description and preliminary results of our new approach to derive wind fields in the MLT region using multi-static, multi-frequency specular meteor radars, called MMARIA.

  14. Polar mesosphere and lower thermosphere dynamics: 2. Response to sudden stratospheric warmings

    NASA Astrophysics Data System (ADS)

    Dowdy, Andrew J.; Vincent, Robert A.; Tsutsumi, Masaki; Igarashi, Kiyoshi; Murayama, Yasuhiro; Singer, Werner; Murphy, Damian J.; Riggin, D. M.

    2007-09-01

    The dynamical response of the polar mesosphere and lower thermosphere (MLT) to sudden stratospheric warmings is investigated using MF radars at Davis (69°S, 78°E), Syowa (69°S, 40°E) and Rothera (68°S, 68°W) in the Antarctic and Poker Flat (65°N, 147°W) and Andenes (69°N, 16°E) in the Arctic. Mean winds, gravity waves and planetary waves are investigated during sudden stratospheric warmings, and comparisons are made with climatological means. The available MF radar data set includes six major sudden stratospheric warmings in the Northern Hemisphere and the unprecedented 2002 Southern Hemisphere major stratospheric warming. Three of the six northern events are relatively weak and could almost be classed as minor warmings, while the larger three have similar characteristics to the event in the Southern Hemisphere. Zonal wind reversals associated with the major warmings in both hemispheres are generally weaker and earlier by several days in the mesosphere than in the stratosphere. There are, however, significant differences between locations in their response to stratospheric warmings. The zonal winds are remarkably weaker than average during both winter and spring around the time of the southern major warming of 2002, but these effects are not observed for the Northern Hemisphere events. Gravity wave activity is found to vary significantly between individual stratospheric warming events and also between individual locations.

  15. Microphysics and chemistry of sulphate aerosols at warm stratospheric temperatures

    NASA Astrophysics Data System (ADS)

    Drdla, K.; Pueschel, R. F.; Strawa, A. W.; Cohen, R. C.; Hanisco, T. F.

    1999-11-01

    Observations of high NOx/NOy ratios (overall 40% larger than modelled values) during the Polar Ozone Loss in the Arctic Region in Summer campaign have led us to re-examine the heterogeneous chemistry of stratospheric aerosol particles during the polar summer period, using the Integrated MicroPhysics and Aerosol Chemistry on Trajectories model. The warm summer temperatures (up to 235 K) imply very concentrated sulphuric acid solutions (80 wt %). On the one hand, these solutions are more likely to freeze, into sulphuric acid monohydrate (SAM), reducing the efficiency of the N2O5 hydrolysis reaction. Including this freezing process increases NOx/NOy ratios but does not improve model/measurement agreement: in polar spring, SAM formation causes the NOx/NOy ratio to be overpredicted whereas freezing has a much smaller effect on nitrogen chemistry during the continuous solar exposure of polar summer. On the other hand, if sulphate aerosols remain liquid, the high acidity may promote acid-catalysed reactions. The most important reaction is CH2O + HNO3, which effectively increases NOx/NOy ratios across a wide range of conditions, improving agreement with measurements. Furthermore, the production of HONO can either enhance gas-phase OH concentrations or promote secondary liquid reactions, including HONO + HNO3 and HONO + HCl. Primary uncertainties include the uptake coefficient of CH2O relevant to reaction with HNO3, the amount of HONO available for secondary reaction, and the relative rates of HONO reaction with HNO3 and HCl. The fate of the formic acid product, whose presence in the stratosphere may be an indicator for the CH2O reaction, and the impact on the stratospheric hydrogen budget are also discussed.

  16. Polar stratospheric clouds: A high latitude warming mechanism in an ancient greenhouse world

    NASA Astrophysics Data System (ADS)

    Sloan, L. Cirbus; Pollard, D.

    The presence of water vapor clouds in the stratosphere produces warming in excess of tropospheric greenhouse warming, via radiative warming in the lower stratosphere. The stratospheric clouds form only in regions of very low temperature and so the warming produced by the clouds is concentrated in polar winter regions. Results from a paleoclimate modeling study that includes idealized, prescribed polar stratospheric clouds (PSCs) show that the clouds cause up to 20°C of warming at high latitude surfaces of the winter hemisphere, with greatest impact in oceanic regions where sea ice is reduced. The modeled temperature response suggests that PSCs may have been a significant climate forcing factor for past time intervals associated with high concentrations of atmospheric methane. The clouds and associated warming may help to explain long-standing discrepancies between model-produced paleotemperatures and geologic proxy temperature interpretations at high latitudes, a persistent problem in studies of ancient greenhouse climates.

  17. Future changes in dynamical processes triggering major stratospheric warmings

    NASA Astrophysics Data System (ADS)

    Ayarzagüena, Blanca; Langematz, Ulrike; Meul, Stefanie; Oberländer, Sophie; Abalichin, Janna; Kubin, Anne

    2013-04-01

    One of the most important examples of the coupling between the boreal troposphere and stratosphere is major stratospheric warmings (MSWs). They are initiated by an anomalously high injection of tropospheric wave activity into the stratosphere that leads to a weakening of the polar vortex, a deceleration of the westerly polar night jet and a warming at high latitudes. Some studies have identified future changes in the main features of these phenomena such as the frequency or seasonal distribution, but with no clear consensus among them. Thus, a detailed analysis of possible future changes in the triggering mechanisms of MSWs is still needed. In this study, we examine potential future changes in the nature of the anomalous wave activity that triggers MSWs by means of time-slice simulations under present and projected future conditions using the EMAC Chemistry-Climate-Model. These experiments include climate forcings by halogens, greenhouse gases (GHG), and prescribed sea surface temperatures (SSTs) (including sea ice concentrations). Following the methodology of Smith and Kushner (2012), we decompose the anomalous vertical wave activity preceding MSWs into its different contributors (i.e., the linear term related to the interference between the climatological stationary waves and wave anomalies; and the nonlinear one, associated with the wave anomalies themselves). First results show that the linear term becomes more important in the future than the nonlinear term and it is predominant in the days prior to the occurrence of the MSWs. Moreover, this increase of the interaction term is primarily due to an intensification of wavenumber-1 wave activity. Given that tropical SST variability, in particular the Pacific one, has been already shown to be linked to an amplification of wavenumber-1 stationary waves, its increase in the future could be a signature of the impact of future changes in tropical SSTs on variations in the occurrence of MSWs. These results will be

  18. Winter stratospheric warmings and their influence on the temperature regime in the lower ionosphere

    NASA Astrophysics Data System (ADS)

    Tarasenko, D. A.; Kidiiarova, V. G.; Milenkova, L. P.; Zakhariev, V. I.; Spasov, Kh. V.

    An analysis is presented of the relationship between the temperature conditions in the D layer of the ionosphere and the intensity of winter stratospheric warmings in different geographic regions, namely, high latitudes and midlatitudes in the Northern Hemisphere and high latitudes in the Southern Hemisphere. The relationships between the temperatures in the stratosphere and mesosphere and the parameters' transmission coefficient, defraction coefficient, and the phase of the two-year equatorial circulation cycle are considered. The temperature conditions in the stratosphere and mesosphere are found to be controlled by the quasi-two-year cycle of the equatorial circulation, which is connected with the intensity of winter stratospheric warmings.

  19. Downward influence of stratospheric final warming events in an idealized model

    NASA Astrophysics Data System (ADS)

    Sun, Lantao; Robinson, Walter A.

    2009-02-01

    The stratospheric final warming is the final transition of the zonal winds from wintertime westerlies to summertime easterlies as solar heating of the high latitude stratosphere increases. Here the stratospheric influence on the tropospheric circulation during the stratospheric final warming events is investigated through ensemble model integrations of a simple dynamical core general circulation model. When the radiative equilibrium temperature in the stratosphere alone is gradually changed from a winter to a summer profile, the model generates realistic final warmings. As in the observations, the simulated final warmings occur at different ``dates'' in different realizations. Following previously published analyses of observed final warmings, we form a climatological springtime transition and compute composite anomalies centered on the final warmings. Simulations for both non-topographic and topographic cases show that starting five days before the final warming, the stratospheric zonal wind rapidly decelerates, in association with a strong upward Eliassen-Palm (EP) flux anomaly and EP flux convergence. Precursor events of wave driven zonal-wind deceleration occur, but at different times in simulations with and without topography. The composite zonal wind anomalies for final warmings with and without topography are compared with each other and with observations. In both cases, a statistically significant zonal wind anomaly extends downward to the surface, similarly to what is observed in the Northern Hemisphere (NH). These tropospheric zonal wind anomalies are stronger in the simulations with topography. Tropospheric geopotential height anomalies across the final warming also resemble NH observations.

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

    NASA Technical Reports Server (NTRS)

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

    1994-01-01

    The evolution of the stratopsheric 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. 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 forecasts 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.

  1. 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.

  2. 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.

  3. Wave Dynamical Coupling of Atmospheres During Sudden Stratospheric Warming Events

    NASA Astrophysics Data System (ADS)

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

    2015-12-01

    The electrodynamic and neutral dynamic behavior of the low-latitude upper atmosphere during sudden stratospheric warming (SSW) events has been investigated. The equatorial electrojet (EEJ) strength and the total electron content (TEC) data from low latitudes, over Indian longitudes, during the mid-winter season in the years 2005 to 2013 are used in this study. Five major and three minor SSW events occurred in the observation duration, wherein the solar activity had varied from minimum (almost no sunspots) to mini-maximum (approximately 50 sunspots of the solar cycle 24). Spectral powers of the quasi-16-day waves in the EEJ and the TEC have been found to be dominant and varying with solar activity and SSW strengths. Specifically, the spectral powers of quasi-16-day type variations during the three dramatic strong SSW events in the years 2006, 2009, and 2013 were found to be very high in comparison with those of other years. For these major events, the amplitudes of the semi-diurnal tides and quasi-16-day waves were found to be highly correlated and were maximum around the peak of SSW, suggesting a strong interaction between the two waves. However, this correlation was poor and the quasi-16-day spectral power was low for the minor events. A strong vertical coupling of atmospheres was noted in spite of the solar activity being relatively higher during 2013, which was, however, explained to be due to the occurrence of a strong SSW event. These results suggest that the wave dynamical vertical coupling of atmospheres is stronger during strong major SSW events and weaker during minor events. Also, SSW events play an important role in enabling the upward coupling of atmospheres even during high solar activity.

  4. 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.

  5. Differing tropospheric responses to stratospheric vortex splits and displacements in a global circulation model

    NASA Astrophysics Data System (ADS)

    O'Callaghan, Amee; Joshi, Manoj; Stevens, David; Mitchell, Daniel

    2014-05-01

    Sudden Stratospheric Warmings (SSWs) have become an increasingly popular topic of study due to the range of potential effects that they have on climate. Often stratospheric anomalies possess the ability to descend into the troposphere. These anomalies can then affect the surface climate for up to two months [Baldwin and Dunkerton, 2001] implying that improved scientific understanding could lead to extended forecasting. However, not all SSWs possess the ability to strongly affect the surface climate. Analysis of reanalysis data has shown that the behaviour of vortex splits and displacements (two classes of SSWs) is clearly distinct. Tropospheric anomalies associated with either type of event contain different spatial structures and often the response associated with vortex splits is stronger [Mitchell et al., 2013]. SSWs are identified in a 200 year integration of the Intermediate General Circulation Model (IGCM). The model's performance is evaluated following the benchmarks of Charlton et al. [2007], and is found to simulate both the frequency and the tropospheric response of SSWs well. Distinctive differences are found in the IGCM's responses to vortex splits and displacements. The vortex split composite displays a significant weakening of the Icelandic Low and Azores High for up to 60 days following an event, indicative of a negative NAM anomaly. On the other hand the vortex displacement composite displays little significant deviation from climatology, implying a lack of NAM anomaly descent. This reaffirms the findings from reanalysis and highlights the need to separate the distinct classes of Sudden Stratospheric Warming events in model studies. We discuss the sensitivity of the model response to other processes such as the parameterisation of gravity waves. References M Baldwin and T Dunkerton. Stratospheric harbingers of anomalous weather regimes. Science, 294:581-584, 2001. A Charlton and Coauthors. A new look at stratospheric sudden warmings. part II

  6. Studies of temperature disturbances of lower and middle atmosphere during stratospheric warmings 2006-2013

    NASA Astrophysics Data System (ADS)

    Medvedev, Andrey; Medvedeva, Irina; Ratovsky, Konstantin; Tolstikov, Maxim

    This paper was devoted to study of sudden winter stratospheric warmings 2006-2013. Initial data were vertical temperature profiles obtained by the Microwave Limb Sounder (MLS) aboard the spacecraft EOS Aura. Shown that the temperature disturbances, propagated during stratospheric warmings are result of interference of at least two waves. Two-wave interference model of stratospheric warming was developed. Characteristics of planetary waves were obtained by using this model. Periods of disturbances vary from 5 to 45 days. Vertical wave numbers range is 20-150 km. Amplitudes and horizontal wave numbers obtained by the two-wave model vary smoothly in space and time, forming vorticity-like structure. We compared warmings 2006-2013 by using global amplitude. Comparison of variations of ionospheric parameters and characteristics of planetary waves in the stratosphere during warmings was done. On the basis of regular, continuous observations of the Irkutsk ionosonde DSP-4, was shown that number of traveling ionospheric disturbances (TIDs) tend to increase during stratospheric warmings. Found correlations between the amount of traveling ionospheric disturbances and the temperature at 80 km, between the daily maximum electron concentration and global amplitude of wave with upward phase velocity between the ion temperature and the amplitude of wave with downward phase velocity over Irkutsk. The work was supported by Russian Foundation for Basic Research Grant 13-05-00153 and RF President Grant of Public Support for RF Leading Scientific Schools (NSh-2942.2014.5).

  7. Dynamical Coupling Between the Stratosphere and the Troposphere: The Influence of External Forcings

    NASA Astrophysics Data System (ADS)

    Hansen, Felicitas; Matthes, Katja

    2013-04-01

    The dynamical coupling between the stratosphere and the troposphere is dominated by planetary waves that are generated in the troposphere by orography and land-sea contrasts. These waves travel upward into the stratosphere where they either dissipate or are reflected downward to impact the troposphere again. Through the interaction with the zonal mean flow planetary waves can induce stratospheric sudden warmings (SSWs), i.e., conditions during NH winter where the stratospheric polar vortex is disturbed so that the zonal mean zonal wind in the NH stratospheric jet becomes easterly and the polar cap meridional temperature gradient reverses. Since strong major SSWs can propagate down into the troposphere and even affect surface weather, SSWs present a strong and clear manifestation of the dynamical coupling in the stratosphere-troposphere system. We will investigate the influence of some external forcings, namely sea surface temperatures (SSTs), anthropogenic greenhouse gases and the quasi-biennial oscillation (QBO), on these coupling processes. Thereby we are interested in how the distribution of SSWs in the winter months changes due to the different forcings, whether the events evolve differently, and whether they show differences in their preconditioning, e.g. a different wave geometry. We will also investigate whether and how vertical reflective surfaces in the stratosphere, which can reflect upward propagating planetary waves, influence the evolution of SSWs. To address these questions, we performed a set of model simulations with NCAR's Community Earth System Model (CESM), a coupled model system including an interactive ocean (POP2), land (CLM4), sea ice (CICE) and atmosphere (NCAR's Whole Atmosphere Community Climate Model (WACCM)) component. Our control experiment is a 140-year simulation with the fully coupled atmosphere-ocean version of CESM. A second experiment is a 55-year simulation with only CESM's atmospheric component WACCM, a fully interactive

  8. 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.

  9. Dynamical amplification of the stratospheric solar response simulated with the Chemistry-Climate Model LMDz-Reprobus

    NASA Astrophysics Data System (ADS)

    Marchand, M.; Keckhut, P.; Lefebvre, S.; Claud, C.; Cugnet, D.; Hauchecorne, A.; Lefèvre, F.; Lefebvre, M.-P.; Jumelet, J.; Lott, F.; Hourdin, F.; Thuillier, G.; Poulain, V.; Bossay, S.; Lemennais, P.; David, C.; Bekki, S.

    2012-02-01

    The impact of the 11-year solar cycle on the stratosphere and, in particular, on the polar regions is investigated using simulations from the Chemistry Climate Model (CCM) LMDz-Reprobus. The annual solar signal clearly shows a stratospheric response largely driven by radiative and photochemical processes, especially in the upper stratosphere. A month-by-months analysis suggests that dynamical feedbacks play an important role in driving the stratospheric response on short timescales. CCM outputs on a 10 days frequency indicate how, in the northern hemisphere, changes in solar heating in the winter polar stratosphere may influence the upward propagation of planetary waves and thus their deposition of momentum, ultimately modifying the strength of the mean stratospheric overtuning circulation at middle and high latitudes. The model results emphasize that the main temperature and wind responses in the northern hemisphere can be explained by a different timing in the occurrence of Sudden Stratospheric Warmings (SSWs) that are caused by small changes in planetary wave propagation depending on solar conditions. The differences between simulations forced by different solar conditions indicate successive positive and negative responses during the course of the winter. The solar minimum simulation generally indicates a slightly stronger polar vortex early in the winter while the solar maximum simulation experiences more early SSWs with a stronger wave-mean flow interaction and reduced zonal wind at mid-latitudes in the upper stratosphere. The opposite response is observed during mid-winter, in February, with more SSWs simulated for solar minimum conditions while solar maximum conditions are associated with a damped planetary wave activity and a reinforced vortex after the initial stratospheric warming period. In late winter, the response is again reversed, as noticed in the temperature differences, with major SSW mostly observed in the solar maximum simulation and less

  10. Stratospheric variability contributed to and sustained the recent hiatus in Eurasian winter warming

    NASA Astrophysics Data System (ADS)

    Garfinkel, Chaim I.; Son, Seok-Woo; Song, Kanghyun; Aquila, Valentina; Oman, Luke D.

    2017-01-01

    The recent hiatus in global-mean surface temperature warming was characterized by a Eurasian winter cooling trend, and the cause(s) for this cooling is unclear. Here we show that the observed hiatus in Eurasian warming was associated with a recent trend toward weakened stratospheric polar vortices. Specifically, by calculating the change in Eurasian surface air temperature associated with a given vortex weakening, we demonstrate that the recent trend toward weakened polar vortices reduced the anticipated Eurasian warming due to increasing greenhouse gas concentrations. Those model integrations whose stratospheric vortex evolution most closely matches that in reanalysis data also simulate a hiatus. While it is unclear whether the recent weakening of the midwinter stratospheric polar vortex was forced, a properly configured model can simulate substantial deviations of the polar vortex on decadal timescales and hence such hiatus events, implying that similar hiatus events may recur even as greenhouse gas concentrations rise.

  11. The Interaction of Radiative and Dynamical Processes during a Simulated Sudden Stratospheric Warming.

    NASA Astrophysics Data System (ADS)

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

    1993-12-01

    An analysis of a spontaneous sudden stratospheric warming that occurred during a 2-year integration of the Langley Research Center 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 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.

  12. A comparison of observed and simulated properties of sudden stratospheric warmings

    NASA Technical Reports Server (NTRS)

    Quiroz, R. S.; Miller, A. J.; Nagatani, R. M.

    1975-01-01

    Review of observational data and dynamical numerical simulations of stratospheric warmings. Classes of warmings, major and minor (major if poleward movement of planetary-scale thermal systems entails reversal of polar circulation at 10 mb or below), trajectories of warm cells, vertical and horizontal scale of warm-air systems, the time-scale of warming, initial zonal flow conditions prior to a warming, circulation reversals, and details of the energy budget before and after a warming are discussed. The 1963 and 1973 types of warmings are contrasted: the strong baroclinic conversion of eddy potential to eddy kinetic energy was not repeated in the latter, but both events were preceded by very large fluxes from the troposphere. Numerical model simulations by various authors are compared and evaluated.

  13. Role of gravity waves in vertical coupling during sudden stratospheric warmings

    NASA Astrophysics Data System (ADS)

    Yiğit, Erdal; Medvedev, Alexander S.

    2016-12-01

    Gravity waves are primarily generated in the lower atmosphere, and can reach thermospheric heights in the course of their propagation. This paper reviews the recent progress in understanding the role of gravity waves in vertical coupling during sudden stratospheric warmings. Modeling of gravity wave effects is briefly reviewed, and the recent developments in the field are presented. Then, the impact of these waves on the general circulation of the upper atmosphere is outlined. Finally, the role of gravity waves in vertical coupling between the lower and the upper atmosphere is discussed in the context of sudden stratospheric warmings.

  14. Ionospheric disturbances in Asian region of Russia during sudden stratospheric warmings

    NASA Astrophysics Data System (ADS)

    Kurkin, Vladimir; Chernigovskaya, Marina; Medvedeva, Irina; Orlov, Igor

    This paper presents an investigation of the subauroral and mid-latitude ionosphere variations in the Asian region of Russia during stratospheric warmings in 2008, 2009 and 2010. We used the data from network of vertical and oblique-incidence sounding ionosounders of ISTP SB RAS. Irkutsk chirp-sounder (vertical incidence sounding) run every 1 minute on 24-hour basis for 30 days in winter of 2008, 2009 and 2010 to study small-scale and medium-scale distur-bances. The experiments on the radio paths Magadan-Irkutsk, Khabarovsk-Irkutsk and Norilsk -Irkutsk were conducted in order to study large-scale ionospheric disturbances. The frequency range was from 4 to 30 MHz, the sweep rate used 500 kHz/sec. To identify the stratospheric warming events the Berlin Meteorological University data (http://strat-www.met.fu-berlin.de) on stratospheric warming at standard isobaric levels and the atmospheric temperature height profiles measured by the Microwave Limb Sounder (MLS) aboard the EOS Aura spacecraft were used. The increase of wave activity in upper ionosphere over Asian region of Russia has recorded during stratospheric warmings. Spectrums of multi-scale variations were derived from the data obtained during the prolonged experiments. The analysis of experimental data has revealed the amplitudes of planetary waves in ionosphere during stratospheric warmings in 2008 and 2010 larger than ones in winter 2009 as opposed to amplitude variations of temperature in stratosphere. This work was supported by Russian Foundation for Basic Research (grant 08-05-00658).

  15. 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.

  16. Global warming mitigation by sulphur loading in the stratosphere: dependence of required emissions on allowable residual warming rate

    NASA Astrophysics Data System (ADS)

    Eliseev, Alexey V.; Chernokulsky, Alexandr V.; Karpenko, Andrey A.; Mokhov, Igor I.

    2010-07-01

    An approach to mitigate global warming via sulphur loading in the stratosphere (geoengineering) is studied, employing a large ensemble of numerical experiments with the climate model of intermediate complexity IAP RAS CM. The model is forced by the historical+SRES A1B anthropogenic greenhouse gases+tropospheric sulphates scenario for 1860-2100 with additional sulphur emissions in the stratosphere in the twenty-first century. Different ensemble members are constructed by varying values of the parameters governing mass, horizontal distribution and radiative forcing of the stratospheric sulphates. It is obtained that, given a global loading of the sulphates in the stratosphere, among those studied in this paper latitudinal distributions of geoengineering aerosols, the most efficient one at the global basis is that peaked between 50° N and 70° N and with a somewhat smaller burden in the tropics. Uniform latitudinal distribution of stratospheric sulphates is a little less efficient. Sulphur emissions in the stratosphere required to stop the global temperature at the level corresponding to the mean value for 2000-2010 amount to more than 10 TgS/year in the year 2100. These emissions may be reduced if some warming is allowed to occur in the twenty-first century. For instance, if the global temperature trend S g in every decade of this century is limited not to exceed 0.10 K/decade (0.15 K/decade), geoengineering emissions of 4-14 TgS/year (2-7 TgS/year) would be sufficient. Even if the global warming is stopped, temperature changes in different regions still occur with a magnitude up to 1 K. Their horizontal pattern depends on implied latitudinal distribution of stratospheric sulphates. In addition, for the stabilised global mean surface air temperature, global precipitation decreases by about 10%. If geoengineering emissions are stopped after several decades of implementation, their climatic effect is removed within a few decades. In this period, surface air

  17. Freezing of polar stratospheric clouds in orographically induced strong warming events

    NASA Astrophysics Data System (ADS)

    Tsias, A.; Prenni, A. J.; Carslaw, K. S.; Onasch, T. P.; Luo, B. P.; Tolbert, M. A.; Peter, Th.

    1997-09-01

    Results from laboratory experiments and microphysical modeling are presented that suggest a potential freezing nucleation mechanism for polar stratospheric cloud (PSC) particles above the water ice frost point (Tice). The mechanism requires very high HNO3 concentrations of about 58 wt% in the droplets, and leads to the freezing of nitric acid dihydrate (NAD) in a highly selective manner in the smallest droplets of an ensemble. In the stratosphere such liquid compositions are predicted to occur in aerosol droplets which are warmed adiabatically with rates of about +150 K/h from below 190 K to 194 K. Such rapid temperature changes have been observed in mountain leewaves that occur frequently in the stratosphere, clearly demonstrating the need for a stratospheric gravity wave climatology.

  18. Impact of the stratospheric warming 2012/2013 on the upper mesosphere

    NASA Astrophysics Data System (ADS)

    Bittner, Michael; Lisa, Kuechelbacher; Carsten, Schmidt; Sabine, Wuest

    2014-05-01

    Impact of the stratospheric warming 2012 / 2013 on the upper mesosphere The effects of stratospheric warming events are not restricted to the stratosphere only. There is also considerable impact on the mesosphere. Remote-sensing data derived by satellite and ground-based instruments are analysed in order to dynamically characterize the stratospheric warming event which took place during winter 2012/2013. The temporal and spatial structure of planetary waves with zonal wave number 1 to 3 is studied from strato- to mesospheric heights using global ozone and temperature data from METOP-GOME-2 and TIMED-SABER, respectively. Ground-based infrared airglow spectrometer measurements (GRIPS) of OH rotational temperature in the mesopause region derived at European mid-latitude NDMC stations complete the data set. Planetary wave amplitudes show characteristic warming pulses whereby planetary wave with zonal wave number 3 significantly changes period and phase speed. The changing planetary wave regime obviously affects gravity wave propagation up to the mesosphere. Indication for varying mesopause airglow layer height is found.

  19. A study of the airglow and the sporadic E layers during stratospheric warming events

    NASA Astrophysics Data System (ADS)

    Mikhalev, Alexander; Ratovsky, Konstantin; Medvedev, Andrey; Medvedeva, Irina; Kurkin, Vladimir; Chernigovskaya, Marina; Kostyleva, Nadegda

    In the present work the events of disturbances of the 557.7 nm and 630 nm airglow and occurrence of sporadic E layer in middle latitudes of Asian region during sudden stratospheric warmings in December 2006 and January-February 2008 are analyzed. Ionosphere data were obtained with the DPS-4 ionosonde located in Irkutsk (52.3N, 104.3E). Airglow measurements were made by the 4-channel zenith photometer and colour CCD imager at ISTP Geophysical observatory located 130 km southwest of Irkutsk. To identify the stratospheric warming events the Berlin Meteorological University data (http://strat-www.met.fu-berlin.de) on stratospheric warming at standard isobaric levels and the atmospheric temperature height profiles measured by the Microwave Limb Sounder (MLS) aboard the EOS Aura spacecraft were used. In some cases we observed correlated diurnal variations of 557.7 nm airglow intensity and Es characteristics. The fact that the correlation between 557.7 nm and Es layer characteristics did not always happen probably can be explained by the different spatial localization of Es layer and emitting layer as well as by the features of their dynamics. During a maximal rise of 557.7 nm airglow its spatial inhomogeneity registered by CCD imager in a continuum was observed. The possible mechanisms of the airglow disturbances and occurrence of sporadic E layers during sudden stratospheric warming are discussed. The work was supported by RAS Presidium Program 16 (Part 3).

  20. 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.

  1. Stratospheric tropical warming event and its impact on the polar and tropical troposphere

    NASA Astrophysics Data System (ADS)

    Kodera, Kunihiko; Eguchi, Nawo; Mukougawa, Hitoshi; Nasuno, Tomoe; Hirooka, Toshihiko

    2017-01-01

    Stratosphere-troposphere coupling is investigated in relation to middle atmospheric subtropical jet (MASTJ) variations in boreal winter. An exceptional strengthening of the MASTJ occurred in association with a sudden equatorward shift of the stratospheric polar night jet (PNJ) in early December 2011. This abrupt transformation of the MASTJ and PNJ had no apparent relation to the upward propagation of planetary waves from the troposphere. The impact of this stratospheric event penetrated into the troposphere in two regions: in the northern polar region and the tropics. Due to the strong MASTJ, planetary waves at higher latitudes were deflected and trapped in the northern polar region. Trapping of the planetary waves resulted in amplification of zonal wave number 1 component, which appeared in the troposphere as the development of a trough over the Atlantic sector and a ridge over the Eurasian sector. A strong MASTJ also suppressed the equatorward propagation of planetary waves, which resulted in weaker tropical stratospheric upwelling and produced anomalous warming in the tropical stratosphere. In the tropical tropopause layer (TTL), however, sublimation of ice clouds kept the temperature change minor. In the troposphere, an abrupt termination of a Madden-Julian Oscillation (MJO) event occurred following the static stability increase in the TTL. This termination suggests that the stratospheric event affected the convective episode in the troposphere.

  2. Rapid Transport of Carbon Monoxide and Water Vapor from Troposphere to Stratosphere via Tropical Convection During Stratospheric Sudden Warming

    NASA Astrophysics Data System (ADS)

    Eguchi, N.; Kodera, K.; Ueyama, R.; Takashima, H.; Deushi, M.

    2015-12-01

    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 carbon monoxide (CO), high water vapor (H2O), low ozone (O3) into the LS over a period of a few days. Evidence of such convective intrusions is observed at the end of January and beginning of February in 2010 associated with increased convective activity over the southern African continent following the onset of stratospheric sudden warming (SSW) event. The modulation of tropical upwelling by SSW appears to force stronger and deeper tropical convection, particularly in the Southern Hemisphere (SH) tropics. The simulation analysis with fine vertical resolution also showed that deep convection especially in the SH became stronger during the SSW event because the upwelling associated with SSW destabilized the TTL [Eguchi et al., ACP, 2015]. The January 2010 SSW event induced the lowest recorded LS temperature in MLS history (2004-13), which destabilized the TTL 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.

  3. 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.

  4. Variations of O2(0-1) and Oh(6,2) Intensities During Stratospheric Warming

    NASA Astrophysics Data System (ADS)

    Ammosov, P. P.; Gavrilyeva, G. A.

    The comparison results of variations of nightly averaged intensities and rotational temperatures of OH(6,2) and O2(0-1) bands in the nightglow measured with the in- frared spectrograph at station Maimaga (63N, 129,5E) and changes of the thermal stratosphere state at heights of 2 and 10 mbar have been given. The daily averaged temperature of the stratosphere in the polar cap (65NU90N) given by Climate Pre- diction Center site, NOAA (www.cpc.ncep.noaa.gov) is used and data for the period of 1999-2000 are analyzed. It is found that during stratospheric warming against the background of the global increase in the O2(0-1) intensity the oscillations of about 10 days time scale are observed. The intensification in the O2(0-1) intensity precedes somewhat the development of the stratospheric warming. The oscillation amplitude decreases as stratospheric warming disappears. Simultaneous oscillations of the same time scale but of smaller amplitude are also detected in the rotational temperatures of O2(0-1). Apparently, when a planetary wave reaches the height of O2(0-1) lumi- nosity (~95 km), it enhances the downward vertical wind. Then, the arrival of the air enriched by atomic oxygen from the thermosphere into the oxygen-deficient meso- sphere increases also. Since the molecular oxygen emission intensity depends on the square of the atomic oxygen concentration the emission rate increases considerably. In this case, the adiabatic heating of the mesosphere is observed simultaneously. Thus, observed oscillations of the intensity and rotational temperature of O2(0-1) can be explained by the modulation of the vertical wind by the planetary wave. Moreover, the planetary wave parameters are such that the intensification of O2(0-1) emission intensity overtakes somewhat the development of the stratospheric warming. Such an evident correlation with the development of the stratospheric warming is not observed in variations of the emission intensity and the rotational temperature of OH.

  5. Latitudinal and longitudinal variability of mesospheric winds and temperatures during stratospheric warming events

    NASA Astrophysics Data System (ADS)

    Hoffmann, P.; Singer, W.; Keuer, D.; Hocking, W. K.; Kunze, M.; Murayama, Y.

    2007-12-01

    Continuous MF and meteor radar observations allow detailed studies of winds in the mesosphere and lower thermosphere (MLT) as well as temperatures around the mesopause. This height region is characterized by a strong variability in winter due to enhanced planetary wave activity and related stratospheric warming events, which are distinct coupling processes between lower, middle and upper atmosphere. Here the variability of mesospheric winds and temperatures is discussed in relation with major and minor stratospheric warmings as observed during winter 2005/06 in comparison with results during winter 1998/99. Our studies are based on MF radar wind measurements at Andenes (69°N, 16°E), Poker Flat (65°N, 147°W) and Juliusruh (55°N, 13°E) as well as on meteor radar observations of winds and temperatures at Resolute Bay (75°N, 95°W), Andenes (69°N, 16°E) and Kühlungsborn (54°N, 12°E). Additionally, energy dissipation rates have been estimated from spectral width measurements using a 3 MHz Doppler radar near Andenes. Particular attention is directed to the changes of winds, turbulence and the gravity wave activity in the mesosphere in relation to the planetary wave activity in the stratosphere. Observations indicate an enhancement of planetary wave 1 activity in the mesosphere at high latitudes during major stratospheric warmings. Daily mean temperatures derived from meteor decay times indicate that strong warming events are connected with a cooling of the 90 km region by about 10 20 K. The onset of these cooling processes and the reversals of the mesospheric circulation to easterly winds occur some days before the changes of the zonal circulation in the stratosphere start indicating a downward propagation of the circulation disturbances from the MLT region to the stratosphere and troposphere during the stratospheric warming events. The short-term reversal of the mesospheric winds is followed by a period of strong westerly winds connected with enhanced

  6. The effects of the Indo-Pacific warm pool on the stratosphere

    NASA Astrophysics Data System (ADS)

    Zhou, Xin; Li, Jianping; Xie, Fei; Ding, Ruiqiang; Li, Yanjie; Zhao, Sen; Zhang, Jiankai; Li, Yang

    2017-03-01

    Sea surface temperature (SST) in the Indo-Pacific warm pool (IPWP) plays a key role in influencing East Asian climate, and even affects global-scale climate change. This study defines IPWP Niño and IPWP Niña events to represent the warm and cold phases of IPWP SST anomalies, respectively, and investigates the effects of these events on stratospheric circulation and temperature. Results from simulations forced by observed SST anomalies during IPWP Niño and Niña events show that the tropical lower stratosphere tends to cool during IPWP Niño events and warm during IPWP Niña events. The responses of the northern and southern polar vortices to IPWP Niño events are fairly symmetric, as both vortices are significantly warmed and weakened. However, the responses of the two polar vortices to IPWP Niña events are of opposite sign: the northern polar vortex is warmed and weakened, but the southern polar vortex is cooled and strengthened. These features are further confirmed by composite analysis using reanalysis data. A possible dynamical mechanism connecting IPWP SST to the stratosphere is suggested, in which IPWP Niño and Niña events excite teleconnections, one similar to the Pacific-North America pattern in the Northern Hemisphere and a Rossby wave train in the Southern Hemisphere, which project onto the climatological wave in the mid-high latitudes, intensifying the upward propagation of planetary waves into the stratosphere and, in turn, affecting the polar vortex.

  7. 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.

  8. 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

  9. 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.

  10. 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.

  11. Ground-based microwave measuring of middle atmosphere ozone and temperature profiles during sudden stratospheric warming

    NASA Astrophysics Data System (ADS)

    Feigin, A. M.; Shvetsov, A. A.; Krasilnikov, A. A.; Kulikov, M. Y.; Karashtin, D. A.; Mukhin, D.; Bolshakov, O. S.; Fedoseev, L. I.; Ryskin, V. G.; Belikovich, M. V.; Kukin, L. M.

    2012-12-01

    We carried out the experimental campaign aimed to study the response of middle atmosphere on a sudden stratospheric warming in winter 2011-2012 above Nizhny Novgorod, Russia (56N, 44E). We employed the ground-based microwave complex for remote sensing of middle atmosphere developed in the Institute of Applied Physics of the Russian Academy of Science. The complex combines two room-temperature radiometers, i.e. microwave ozonometer and the stratospheric thermometer. Ozonometer is a heterodyne spectroradiometer, operating in a range of frequencies that include the rotation transition of ozone molecules with resonance frequency 110.8 GHz. Operating frequency range of the stratospheric thermometer is 52.5-5.4 GHz and includes lower frequency edge of 5 mm molecular oxygen absorption bands and among them two relatively weak lines of O2 emission. Digital fast Fourier transform spectrometers developed by "Acqiris" are employed for signal spectral analysis. The spectrometers have frequency range 0.05-1 GHz and realizes the effective resolution about 61 KHz. For retrieval vertical profiles of ozone and temperature from radiometric data we applied novel method based on Bayesian approach to inverse problem solution, which assumed 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 introduce the results of the campaign in comparison with Aura MLS data. Presented data includes one sudden stratospheric warming event which took place in January 13-14 and was accompanied by temperature increasing up to 310 K at 45 km height. During measurement period, ozone and temperature variations were (almost) anti-correlated, and total ozone abundance achieved a local maxima during the stratosphere cooling phase. In general, results of ground-based measurements are in good agreement with

  12. Dynamic characteristics of atmospheric planetary waves during stratospheric warmings in winter 2008

    NASA Astrophysics Data System (ADS)

    Chernigovskaya, Marina; Medvedev, Andrey; Tolstikov, Maxim; Medvedeva, Irina; Ratovsky, Konstantin

    2010-05-01

    The wave mechanism of energy transfer is quite significant in transferring energy in the Earth's atmosphere. Atmospheric internal waves of different spatial and temporal scales (including 1-30-day planetary waves) transfer a great deal of kinetic energy from the troposphere and stratosphere to higher atmospheric layers. As deduced from experimental data, systems of strong zonal stratospheric winds prevent penetration of planetary waves from the troposphere to the upper atmosphere (mesosphere and thermosphere), but the part of their energy reaches the upper atmosphere. Planetary waves are in many respects associated with such interesting phenomena in the Earth's stratosphere as sudden winter stratospheric warmings (SSW), observed almost every winter and characterized by geographical nonuniformity. High concentration of stratospheric warming centers is typical of the Asian region of Russia. We examined dynamic characteristics of atmospheric planetary waves observed in the Asian region of Russia in the longitudinal sector of ~80-125°E during stratospheric warmings in winter 2008. Satellite data on vertical temperature distribution obtained by the Microwave Limb Sounder (MLS) aboard the spacecraft EOS Aura and Irkutsk digisonde DPS-4 data were used. It has been established that pronounced wave-like temperature disturbances with characteristic periods of 10-14 days were observed in the Asian region of Russia in the sector of ~80-125°E and 40-64°N over a height range of 20-90 km during development of the SSW in January-February 2008. Revealed here is a high correlation between temperature disturbances and the minimum frequency of reflection in the Irkutsk digisonde DPS-4 ionograms. This paper offers a method for investigating characteristics of propagation of long-term temperature disturbances by a cross-correlation analysis. This method consists in determining delays between disturbances observed at different points and in deriving a system of linear equations for

  13. Solar quiet current response in the African sector due to a 2009 sudden stratospheric warming event

    NASA Astrophysics Data System (ADS)

    Bolaji, O. S.; Oyeyemi, E. O.; Owolabi, O. P.; Yamazaki, Y.; Rabiu, A. B.; Okoh, D.; Fujimoto, A.; Amory-Mazaudier, C.; Seemala, G. K.; Yoshikawa, A.; Onanuga, O. K.

    2016-08-01

    We present solar quiet (Sq) variation of the horizontal (H) magnetic field intensity deduced from Magnetic Data Acquisition System (MAGDAS) records over Africa during an unusual strong and prolonged 2009 sudden stratospheric warming (SSW) event. A reduction in the SqH magnitude that enveloped the geomagnetic latitudes between 21.13°N (Fayum FYM) in Egypt and 39.51°S (Durban DRB) in South Africa was observed, while the stratospheric polar temperature was increasing and got strengthened when the stratospheric temperature reached its maximum. Another novel feature associated with the hemispheric reduction is the reversal in the north-south asymmetry of the SqH, which is indicative of higher SqH magnitude in the Northern Hemisphere compared to the Southern Hemisphere during SSW peak phase. The reversal of the equatorial electrojet (EEJ) or the counter electrojet (CEJ) was observed after the polar stratospheric temperature reached its maximum. The effect of additional currents associated with CEJ was observed in the Southern Hemisphere at middle latitude. Similar changes were observed in the EEJ at the South America, Pacific Ocean, and Central Asia sectors. The effect of the SSW is largest in the South American sector and smallest in the Central Asian sector.

  14. Impact of the Stratospheric Warming 2012 / 2013 on the Middle Atmosphere

    NASA Astrophysics Data System (ADS)

    Bittner, M.; Küchelbacher, L.; Schmidt, C.; Wüst, S.; Eriksen Holmen, S.; Espy, P. J.; Gavrilyeva, G.; Yee, J. H.; Mlynczak, M. G.; Russell, J. M., III

    2014-12-01

    The effects of stratospheric warming events are not restricted to the stratosphere only. There is considerable impact on the mesosphere. Global ozone and temperature data derived from the METOP-A-GOME-2 and TIMED-SABER satellites, respectively, and rotational temperatures obtained by ground-based infrared airglow spectrometer measurements (GRIPS) including polar stations within the Network for Mesospheric Change, NDMC, are analyzed in order to characterize both larger scale (planetary waves) and smaller scale (gravity waves) atmospheric dynamics during minor and major stratospheric warming events which took place in winter 2012/2013 in the Northern Hemisphere. The planetary wave regime is found being dominated by zonal wavenumbers 1 and 2 which significantly trigger the observed stratwarming; induced momentum on the background zonal flow due to wave breaking is estimated. As a consequence of the stratwarming the planetary wave number 3 is found being modified significantly in its wave characteristics (phase speed, frequency). Impact of the stratwarming on the upper mesosphere / lower thermosphere is discussed. Evidence for some mesospheric cooling prior to the stratwarming is found. Gravity wave characteristics in that altitude regime seem to be altered. There is also evidence that the mesopause airglow layer might have changed its geometric height during these events.

  15. 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.

  16. Influence of planetary wave activity on the stratospheric final warming and spring ozone

    NASA Astrophysics Data System (ADS)

    Salby, Murry L.; Callaghan, Patrick F.

    2007-10-01

    A three-dimensional model of dynamics and photochemistry is used to investigate the influence of planetary wave activity on the seasonal evolution of the wintertime stratosphere, which dictates springtime conditions. The final warming and springtime ozone are each found to depend strongly upon planetary wave activity during the disturbed season. The integrations reproduce their observed dependence, which enters through anomalous upward Eliassen-Palm (EP) flux from the troposphere and equatorial wind associated with the Quasi-Biennial Oscillation (QBO). Of those major influences, changes of upward EP flux are predominant. Changes representative of those in the observed record alter the timing of the final warming by as much as 1-2 months. Much the same lag distinguishes warm and cold winters in the observed record. Accompanying the shift in the final warming is a change of ozone at spring equinox. Magnified over the Arctic, anomalous springtime ozone develops largely through anomalous isentropic mixing by planetary waves. Such mixing, which precedes the final warming, incorporates ozone-rich air from lower latitude, leading to enriched polar ozone during spring. Relative to disturbed conditions, springtime polar ozone under undisturbed conditions appears depleted by some 60 DU. Derived through anomalous transport, the same difference characterizes observed changes between warm and cold winters. Much of the apparent depletion is eventually eliminated with the onset of isentropic mixing, as it is in the observed record. Together with anomalous dynamical structure, such behavior has implications important to the interpretation of interannual changes.

  17. On the life cycle of a stratospheric intrusion and its dispersion into polluted warm conveyor belts

    NASA Astrophysics Data System (ADS)

    Cooper, O.; Forster, C.; Parrish, D.; Dunlea, E.; Hübler, G.; Fehsenfeld, F.; Holloway, J.; Oltmans, S.; Johnson, B.; Wimmers, A.; Horowitz, L.

    2004-12-01

    The aircraft-based 2002 Intercontinental Transport and Chemical Transformation experiment intercepted and chemically analyzed pollution plumes transported from Asia to the western United States. The research flight on 10-11 May 2002 detected mixing between polluted and stratospheric air at midtropospheric levels above the California coast. This study uses a Lagrangian domain-filling trajectory technique to illustrate that this event was the result of mixing between two warm conveyor belts (WCB) containing Asian pollution and the remnants of a deep tropopause fold from a downstream midlatitude cyclone (referred to as the stratospheric component of a dry airstream or SCDA). Advection of the trajectory particles shows how the SCDA decayed over 7.5 days. One component dispersed into a downstream WCB, while another component descended into the lower troposphere and became entrained by an upwind WCB. After 7.5 days of transport 22% of the SCDA mass was transported into the troposphere. The portions of the SCDA that penetrated to the lowest altitudes had the greatest likelihood of being transported into the troposphere. For example, over 90% of the SCDA at altitudes below the 600 hPa level was transported to the troposphere, but none of the mass at the 200 hPa level was exchanged. More than half of the exchange occurred during the first 48 hours as the deepest portions of the tropopause fold decayed over the Pacific. The rest of the exchange occurred over the following 5.5 days as the remnants of the SCDA sheared apart along the edge of the stratospheric polar vortex and became entrained into subsequent tropopause folds and vortex breakaway features. Stratosphere to troposphere exchange resulted in the transport of 0.5 Tg of stratospheric ozone to the troposphere during the 7.5 day study period. Roughly half of the SCDA particles that entered the troposphere dispersed into the upwind and downwind WCBs.

  18. 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.

  19. Do strong warm ENSO events control the phase of the stratospheric QBO?

    NASA Astrophysics Data System (ADS)

    Christiansen, Bo; Yang, Shuting; Madsen, Marianne Sloth

    2016-10-01

    Although there in general are no significant long-term correlations between the quasi-biennial oscillation (QBO) and the El Niño-Southern Oscillation (ENSO) in observations, we find that the QBO and the ENSO were aligned in the 3 to 4 years after the three warm ENSO events in 1982, 1997, and 2015. We investigate this indicated relationship with a version of the EC-Earth climate model which includes nonorographic gravity waves. We analyze the modeled QBO in ensembles forced with climatological sea surface temperatures (SSTs) and observed SSTs. In the ensemble with observed SSTs we find a strong and significant alignment of the ensemble members in the equatorial stratospheric winds in the 2 to 4 years after the strong ENSO event in 1997. This alignment also includes the observed QBO. No such alignment is found in the ensemble with climatological SSTs. These results indicate that strong warm ENSO events can lock the phase of the QBO.

  20. 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

  1. Stratospheric sudden warming impact on the tropical troposphereseen in NICAM - a global non-hydrostatic model

    NASA Astrophysics Data System (ADS)

    Eguchi, N.; Kodera, K.; Nasuno, T.

    2012-04-01

    To investigate the dynamical interaction between the stratosphere and troposphere through the tropical transition layer (TTL), the impact of stratospheric sudden warming (SSW) on the tropical troposphere has been discussed mainly by using the observational data [e.g., Kodera and Yamada, 2004; Eguchi and Kodera, 2007; Eguchi and Kodera, 2010]. During the SSW period, the abrupt upward motion in the tropics associated with the stronger meridional circulation due to SSW induces adiabatic cooling not only in the lower stratosphere but also in the upper troposphere. In addition, the convection in the tropics is active over the major three tropical convective regions and the cirrus clouds occur frequently. It also suggested by a couple of SSW event studies that the internal effect in the troposphere (e.g., induced by the wave propagation) is small. In recently, Kodera et al. [2011] has shown by the model simulation data that the meridional circulation between troposphere and stratosphere at the tropical region is strongly connected and the tropical tropospheric meridional circulation becomes stronger after the onset of SSW. These studies show clearly that the stratospheric dynamics affects the distributions of the tropospheric parameters, especially in the tropics. The aim of the present study is to investigate the mechanism of the interaction between the stratosphere and troposphere during the SSW by using a simulation data with a global nonhydrostatic model, Nonhydrostatic ICosahedral Atmospheric Model (NICAM) [Satoh, et al 2008]. The simulation period is December 2009 to February 2010, and the horizontal mesh size of 14 km and vertically stretched 40-layers (z= 0 ~38 km) are used. Three hourly (hourly) outputs for 3D (2D) variables are analyzed in the present study. During the analysis period, the SSW occurred in the northern hemisphere around the middle of January (the date of the SSW is 15 January). The onset date is defined by the temperature tendency at 10 h

  2. Ionospheric Response to a Sudden Stratospheric Warming at High Solar Activity

    NASA Astrophysics Data System (ADS)

    Fuller-Rowell, T. J.; Fang, T.; Wang, H.; Wu, F.; Akmaev, R. A.

    2013-12-01

    The recent solar minimum has been an ideal opportunity to study the impact of lower atmosphere dynamics on the thermosphere and ionosphere. During January 2009, for instance, the response to a particularly large sudden stratospheric warming revealed large changes in the vertical plasma drift at the magnetic equator. The response in total electron content showed a 50% increase in the morning hours and a 50% decrease in the afternoon, compared to the typical diurnal variation. Modeling the period enable the physical processes to be unraveled. The change appeared to be in part due to a change in phase of the upward propagating semi-diurnal migrating tide. Numerical simulations have been performed to determine the likely response of the upper atmosphere if this particular stratospheric warming had occurred at higher solar activity. Theory might suggest the wind fields reaching the lower thermosphere dynamo region would be similar, so the changes in the electric fields would be more controlled by the plasma density and conductivity changes. The numerical simulation shed light on the likely response and whether the changes if plasma density would likely be discernable from other sources of solar and geomagnetic variability at high solar activity.

  3. 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

    2016-12-01

    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.

  4. 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

  5. The major stratospheric final warming in 2016: dispersal of vortex air and termination of Arctic chemical ozone loss

    NASA Astrophysics Data System (ADS)

    Manney, Gloria L.; Lawrence, Zachary D.

    2016-12-01

    The 2015/16 Northern Hemisphere winter stratosphere appeared to have the greatest potential yet seen for record Arctic ozone loss. Temperatures in the Arctic lower stratosphere were at record lows from December 2015 through early February 2016, with an unprecedented period of temperatures below ice polar stratospheric cloud thresholds. Trace gas measurements from the Aura Microwave Limb Sounder (MLS) show that exceptional denitrification and dehydration, as well as extensive chlorine activation, occurred throughout the polar vortex. Ozone decreases in 2015/16 began earlier and proceeded more rapidly than those in 2010/11, a winter that saw unprecedented Arctic ozone loss. However, on 5-6 March 2016 a major final sudden stratospheric warming ("major final warming", MFW) began. By mid-March, the mid-stratospheric vortex split after being displaced far off the pole. The resulting offspring vortices decayed rapidly preceding the full breakdown of the vortex by early April. In the lower stratosphere, the period of temperatures low enough for chlorine activation ended nearly a month earlier than that in 2011 because of the MFW. Ozone loss rates were thus kept in check because there was less sunlight during the cold period. Although the winter mean volume of air in which chemical ozone loss could occur was as large as that in 2010/11, observed ozone values did not drop to the persistently low values reached in 2011.We use MLS trace gas measurements, as well as mixing and polar vortex diagnostics based on meteorological fields, to show how the timing and intensity of the MFW and its impact on transport and mixing halted chemical ozone loss. Our detailed characterization of the polar vortex breakdown includes investigations of individual offspring vortices and the origins and fate of air within them. Comparisons of mixing diagnostics with lower-stratospheric N2O and middle-stratospheric CO from MLS (long-lived tracers) show rapid vortex erosion and extensive mixing during

  6. Equatorial and low-latitude ionospheric response due to 2009 sudden stratospheric warming, South American sector.

    NASA Astrophysics Data System (ADS)

    Fagundes, Paulo Roberto; Gende, Mauricio; De Jesus, Rodolfo; Goncharenko, Larisa; Coster, Anthea; Kavutarapu, Venkatesh; De Abreu, Alessandro; Pillat, ValdirGil; Pezzopane, Michael

    The equatorial and low-latitude ionosphere/thermosphere system is permanently 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. Until recently 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 electroject. 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, recently an unexpected coupling between high latitude, -mid latitude, and -equatorial/low-latitude was discovered during sudden stratospheric warming (SSW). The exploration of all aspects involved in this process must be investigated in order to improve our knowledge about the Earth's atmosphere. This investigation, studies the consequences of the vertical coupling from lower to upper atmosphere during a major Northern Hemisphere sudden stratospheric warming, which took place in January 2009, on the equatorial and low-latitude ionosphere in the Southern Hemisphere. Using 16 ground-based GPS stations over the Brazilian sector, spanning from latitude 2.8N to 30.1S and longitude 62.0W to 37.7W, it was possible to notice that the ionosphere was disturbed by SSW from the Equator to low latitude. The TEC at all 16 stations was severely disturbed during several days after the SSW temperature peak.

  7. Behavior of zonal mean aerosol extinction ratio and its relationship with zonal mean temperature during the winter 1978-1979 stratospheric warming

    NASA Technical Reports Server (NTRS)

    Wang, P.-H.; Mccormick, M. P.

    1985-01-01

    The behavior of the zonal mean aerosol extinction ratio in the lower stratosphere near 75 deg N and its relationship with the zonal mean temperature during the January-February 1979 stratospheric sudden warming have been investigated based on the satellite sensor SAM II (Stratospheric Aerosol Measurement) and auxiliary meteorological measurements. The results indicate that distinct changes in the zonal mean aerosol extinction ratio occurred during this stratospheric sudden warming. It is also found that horizontal eddy transport due to planetary waves may have played a significant role in determining the distribution of the zonal mean aerosol extinction ratio.

  8. Impacts of sudden stratospheric warming on general circulation of the thermosphere

    NASA Astrophysics Data System (ADS)

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

    2015-12-01

    Impacts of sudden stratospheric warming (SSW) on the thermosphere were studied using a gravity wave (GW)-resolving whole atmosphere model. During an SSW event, the mesosphere at high latitudes cools, and the lower thermosphere becomes warm. At the peak of the SSW event, a temperature drop occurs above an altitude of 150 km at high latitudes. Our results indicate that the SSW event strongly affects meridional circulation and GW drag in the thermosphere. In the lower thermosphere, upward wind in the Arctic region, southward wind in the region between the North Pole and the South Pole, and downward wind in the Antarctic region are dominant before SSW occurs. The SSW event reverses meridional circulation at altitudes between 90 and 125 km in the Northern Hemisphere. During the SSW event, downward wind in the Arctic region and northward wind in the Northern Hemisphere prevail in the lower thermosphere. A detailed analysis revealed that during the SSW event, the change in meridional circulation is caused by the attenuation of the GW drag, and we identified the mechanism responsible for this attenuation. Moreover, we assessed the impacts of SSW on temperatures in the equatorial region and Southern Hemisphere.

  9. Structure and Evolution of Singular Vectors in a Global Forecast Model during the January 2009 Stratospheric Sudden Warming

    NASA Astrophysics Data System (ADS)

    Eckermann, S. D.; Reynolds, C. A.; Coy, L.

    2012-12-01

    Singular vectors (SV) of a global forecast model are computed over deep domains of the Northern Hemisphere throughout January 2009 to investigate rapidly-growing perturbations and troposphere-stratosphere predictability. In early-to-mid January, when the stratospheric vortex was relatively undisturbed, the fastest growing stratospheric SV perturbations form initially on the equatorward flanks of the vortex jet as isolated tilted packet-like structures that grow rapidly in energy and horizontal scale, propagate into the core of the vortex jet and self-organize into quasi-barotropic Rossby-wave trains. From 22-28 January, a period characterized by a major wave-2 stratospheric sudden warming (SSW), stratospheric SV structure and evolution change dramatically. SV energy growth increases and the leading stratospheric SV (SV1) assumes an hemispheric geopotential height structure closely resembling a negative anomaly in the northern annular mode (NAM). Forecasts with atmospheric initial conditions perturbed with initial ±SV1 perturbations produce rapid growth of this hemispheric annular perturbation, which in turn either enhances or suppresses the forecast strength of the SSW. Relative to a control forecast, +SV1-perturbed forecasts increase the strength of the forecast SSW, as reflected in the rate and degree of vortex splitting, the magnitude of forced mean stratospheric easterlies and the descent rate of easterly shear zones, leading to mean easterlies in the high-latitude troposphere and stratosphere after 3-4 days. Conversely, -SV1-perturbed forecasts weaken and then halt the warming, yielding a minor SSW with mean westerlies throughout the high-latitude troposphere and stratosphere after ~4 days.This forecast SSW sensitivity to growing ±SV1 perturbations arises in each case as a positive feedback driven by large reinforcing changes in planetary-wave Eliassen-Palm (EP) fluxes, with +SV1-perturbed forecasts increasing poleward EP fluxes and -SV1-perturbed forecasts

  10. Quantifying the response strength of the southern stratospheric polar vortex to Indian Ocean warming in austral summer

    NASA Astrophysics Data System (ADS)

    Li, Shuanglin; Chen, Xiaoting

    2014-03-01

    A previous multiple-AGCM study suggested that Indian Ocean Warming (IOW) tends to warm and weaken the southern polar vortex. Such an impact is robust because of a qualitative consistency among the five AGCMs used. However, a significant difference exists in the modeled strengths, particularly in the stratosphere, with those in three of the AGCMs (CCM3, CAM3, and GFS) being four to five times as strong as those in the two other models (GFDL AM2, ECHAM5). As to which case reflects reality is an important issue not only for quantifying the role of tropical ocean warming in the recent modest recovery of the ozone hole over the Antarctic, but also for projecting its future trend. This issue is addressed in the present study through comparing the models' climatological mean states and intrinsic variability, particularly those influencing tropospheric signals to propagate upward and reach the stratosphere. The results suggest that differences in intrinsic variability of model atmospheres provide implications for the difference. Based on a comparison with observations, it is speculated that the impact in the real world may be closer to the modest one simulated by GFDL AM2 and ECHAM5, rather than the strong one simulated by the three other models (CCM3, CAM3 and GFS). In particular, IOW during the past 50 years may have dynamically induced a 1.0°C warming in the polar lower stratosphere (˜ 100 hPa), which canceled a fraction of radiative cooling due to ozone depletion.

  11. Lunar tidal effects during the 2013 stratospheric sudden warming as simulated by the TIME-GCM

    NASA Astrophysics Data System (ADS)

    Maute, A. I.; Forbes, J. M.; Zhang, X.; Fejer, B. G.; Yudin, V. A.; Pedatella, N. M.

    2015-12-01

    Stratospheric Sudden Warmings (SSW) are associated with strong planetary wave activity in the winterpolar stratosphere 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

  12. The Plunger Hypothesis: an overview of a new theory of stratosphere-troposphere dynamic coupling

    NASA Astrophysics Data System (ADS)

    Clark, S.; Baldwin, M. P.; Stephenson, D.

    2015-12-01

    I will demonstrate the advantages of a new method of quantifying polar stratosphere-troposphere coupling by considering large-scale movements of mass into and out of the polar stratosphere. This project aims to use these mass movements to explain pressure and temperature anomalies throughout the polar troposphere and lower stratosphere in the aftermath of extreme stratospheric events. We hypothesise that these mass movements are induced by deposition of momentum by breaking waves in the stratosphere, slowing the wintertime polar vortex, and so are associated with sudden stratospheric warmings (SSWs). Such a mass movement in the upper stratosphere acts to compress the polar atmosphere below it in the manner of a plunger. In this way the pressure anomaly in the upper polar stratosphere '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 stratospheric 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 stratospheric anomalies in the polar cap, and so a way to predict tropospheric variability given stratospheric information. This work forms part of a three and a half year PhD project.

  13. A Resonant Wave in a Numerical Model of the 1979 Sudden Stratospheric Warming.

    NASA Astrophysics Data System (ADS)

    Smith, Anne K.; Avery, Susan K.

    1987-11-01

    A simple numerical model of the stratosphere has been used to examine the possibility that a resonant growth of wave 2 was responsible for the 1979 major sudden warning. The model solves for linear steady state solutions to the quasi-geographic wave equation in the presence of realistic damping. The basic state is taken from observations (NMC and LIMS), and the frequency of the wave forcing is varied over a wide range. The model results show that in the days during the initial observed amplification of wave 2 (14-15 February), a clear resonant mode existed. The maximum response is for a wave moving eastward with a period of 12-16 days. Another peak at very low frequency (period greater than 100 days) occurs on 22 February. Other days during the period 12-24 February show weaker, but nevertheless significant peaks for particular frequencies. The frequency of the maximum is lower for later days and is nearly stationary at the height of the warming around 21 February. This frequency shift found in the model corresponds closely to the observed wave behavior.Although the details of the results vary with changes in the model resolution or lower boundary position, the resonant wave does not disappear. However, when the wave forcing is applied at the earth&s surface rather than in the tropopause region, no resonance occurs. To test the effect of the lower boundary, the troposphere-stratosphere model was run with an internal vorticity forcing similar to the structure of the observed wave 2 in the troposphere. In this case the frequency dependence of the amplitude within the stratosphere was similar to that of the model with a tropopause boundary, although the magnitude was considerably smaller. This suggests that for resonance to have occurred, a planetary scale disturbance that did not propagate from the surface must have been maintained in the upper troposphere. The two well-developed blocking ridges present in the troposphere during this period may have contributed

  14. Subtropical influence on January 2009 major sudden stratospheric warming event: diagnostic analysis

    NASA Astrophysics Data System (ADS)

    Schneidereit, Andrea; Peters, Dieter; Grams, Christian; Wolf, Gabriel; Riemer, Michael; Gierth, Franziska; Quinting, Julian; Keller, Julia; Martius, Olivia

    2015-04-01

    In January 2009 a major sudden stratospheric warming (MSSW) event occurred with the strongest NAM anomaly ever observed at 10 hPa. Also stratospheric 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 warm 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

  15. Chemical and dynamical impacts of stratospheric sudden warmings on Arctic ozone variability

    NASA Astrophysics Data System (ADS)

    Strahan, S. E.; Douglass, A. R.; Steenrod, S. D.

    2016-10-01

    We use the Global Modeling Initiative (GMI) chemistry and transport model with Modern-Era Retrospective Analysis for Research and Applications (MERRA) meteorological fields to quantify heterogeneous chemical ozone loss in Arctic winters 2005-2015. Comparisons to Aura Microwave Limb Sounder N2O and O3 observations show the GMI simulation credibly represents the transport processes and net heterogeneous chemical loss necessary to simulate Arctic ozone. We find that the maximum seasonal ozone depletion varies linearly with the number of cold days and with wave driving (eddy heat flux) calculated from MERRA fields. We use this relationship and MERRA temperatures to estimate seasonal ozone loss from 1993 to 2004 when inorganic chlorine levels were in the same range as during the Aura period. Using these loss estimates and the observed March mean 63-90°N column O3, we quantify the sensitivity of the ozone dynamical resupply to wave driving, separating it from the sensitivity of ozone depletion to wave driving. The results show that about 2/3 of the deviation of the observed March Arctic O3 from an assumed climatological mean is due to variations in O3 resupply and 1/3 is due to depletion. Winters with a stratospheric sudden warming (SSW) before mid-February have about 1/3 the depletion of winters without one and export less depletion to the midlatitudes. However, a larger effect on the spring midlatitude ozone comes from dynamical differences between warm and cold Arctic winters, which can mask or add to the impact of exported depletion.

  16. The Major Stratospheric Sudden Warming of January 2013: Analyses and Forecasts in the GEOS-5 Data Assimilation System

    NASA Technical Reports Server (NTRS)

    Coy, Lawrence; Pawson, Steven

    2014-01-01

    We examine the major stratosphere sudden warming (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 stratosphere 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 warming. The overall success of the 5-day forecasts provides motivation to produce regular 10-day forecasts with GEOS-5, to better support studies of stratosphere-troposphere interaction.

  17. Multimodel comparison of the ionosphere variability during the 2009 sudden stratosphere warming

    NASA Astrophysics Data System (ADS)

    Pedatella, N. M.; Fang, T.-W.; Jin, H.; Sassi, F.; Schmidt, H.; Chau, J. L.; Siddiqui, T. A.; Goncharenko, L.

    2016-07-01

    A comparison of different model simulations of the ionosphere variability during the 2009 sudden stratosphere warming (SSW) is presented. The focus is on the equatorial and low-latitude ionosphere simulated by the Ground-to-topside model of the Atmosphere and Ionosphere for Aeronomy (GAIA), Whole Atmosphere Model plus Global Ionosphere Plasmasphere (WAM+GIP), and Whole Atmosphere Community Climate Model eXtended version plus Thermosphere-Ionosphere-Mesosphere-Electrodynamics General Circulation Model (WACCMX+TIMEGCM). The simulations are compared with observations of the equatorial vertical plasma drift in the American and Indian longitude sectors, zonal mean F region peak density (NmF2) from the Constellation Observing System for Meteorology, Ionosphere, and Climate (COSMIC) satellites, and ground-based Global Positioning System (GPS) total electron content (TEC) at 75°W. The model simulations all reproduce the observed morning enhancement and afternoon decrease in the vertical plasma drift, as well as the progression of the anomalies toward later local times over the course of several days. However, notable discrepancies among the simulations are seen in terms of the magnitude of the drift perturbations, and rate of the local time shift. Comparison of the electron densities further reveals that although many of the broad features of the ionosphere variability are captured by the simulations, there are significant differences among the different model simulations, as well as between the simulations and observations. Additional simulations are performed where the neutral atmospheres from four different whole atmosphere models (GAIA, HAMMONIA (Hamburg Model of the Neutral and Ionized Atmosphere), WAM, and WACCMX) provide the lower atmospheric forcing in the TIME-GCM. These simulations demonstrate that different neutral atmospheres, in particular, differences in the solar migrating semidiurnal tide, are partly responsible for the differences in the simulated

  18. Worldwide impacts of sudden stratospheric warmings on the ionosphere and thermosphere

    NASA Astrophysics Data System (ADS)

    Goncharenko, Larisa; Coster, Anthea; Zhang, Shun-Rong; Erickson, Phillip; Aponte, Nestor; Harvey, V. Lynn; Pedatella, Nicholas; Maute, Astrid

    2016-04-01

    Recent studies have demonstrated large variations in the low-latitude ionosphere during strong, persistent meteorological disturbances known as sudden stratospheric warmings. 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

  19. Gravity wave effects in the thermosphere during sudden stratospheric warmings and vertical coupling between the lower and upper atmosphere

    NASA Astrophysics Data System (ADS)

    Yiǧit, Erdal; Medvedev, Alexander S.

    2016-07-01

    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 stratospheric warmings, 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 warming (Yiǧit et al., 2014)}. References: Yiǧit, E., and A. S. Medvedev (2012), Gravity waves in the thermosphere during a sudden stratospheric warming, 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 stratospheric warming, J. Geophys. Res. Space Physics, 119, doi:10.1002/2013JA019283.

  20. A study of the effects of stratospheric warming on the arctic oscillation and its teleconnections

    NASA Astrophysics Data System (ADS)

    Mooring, R.

    2003-04-01

    The Arctic Oscillation (AO), the leading mode of mean sea level pressure from 20oN poleward, is a robust naturally occurring phenomenon that has teleconnections with several tropospheric and stratospheric fields. It is believed, however, that stratospheric heating is responsible for a major portion of the variability of the AO. Because ozone and other greenhouse gas concentrations help to regulate the lower stratosphere's temperature, it is my belief that by varying the concentrations of these greenhouse gases, the polar vortex, AO, and their teleconnections can be affected. The case studies used here vary the concentrations of O_3 and CO_2 in the lower stratosphere and H_2O in the lower stratosphere and upper troposphere of the stand alone version of the CCM3 global climate model. This poster identifies the significant differences and similarities found in each case study as compared to a control run with no changes.

  1. Short period airglow temperature and emission rate oscillations in the high Arctic MLT region during stratospheric warming events

    NASA Astrophysics Data System (ADS)

    Lederman, J. I.

    2015-12-01

    The airglow is a photochemical glow in the upper atmosphere that occurs in thin layers corresponding to different chemical processes. The O2 Atmospheric airglow layer exists at about 94 km altitude and the hydroxyl layer at about 87 km. The intensity of the light gives information about the concentration of atomic oxygen there, while the shape of the spectrum gives accurate values of the temperature. In this investigation, these are measured above Eureka in the Canadian Arctic (80N, 86W) using an instrument called SATI (Spectral Airglow Temperature Imager). The optical data are employed to characterize short period oscillations in rotational temperatures and integral emission rates of OH (6,2) Meinel and O2 (0,1) Atm. bands during a stratospheric warming event from January 2015. In this presentation, SATI observations coupled with wind radiosonde data at Eureka and the ECMWF model are used to compare the January 2015 warming with the major stratospheric warming event of January 2009, thereby providing a window into high frequency atmospheric wave dynamics at play between altitudes of 20 km - 100 km.

  2. The study of the special features of winter stratospheric warming manifestations over Tomsk according to the lidar temperature measurements

    NASA Astrophysics Data System (ADS)

    Marichev, V. N.; Samokhvalov, I. V.

    2014-11-01

    In the article the lidar observations of the winter stratosphere warming manifestations of (SW) 2011-13 over Tomsk are considered. In 2010/11 the winter warming took place in January with insignificant positive temperature deviations from the mean monthly values in its first decade and then two maxima on the 14th and 15th of January at the altitude of 30-40 km with a deviation to 45K. In 2011/12 the beginning of the SW was recorded from lidar measurements on December 26 and lasted for two decades of January. The maximum development of SW was at the end of December 2011 - the first decade of January. The biggest temperature deviations were at the 40-60K level in the height interval of 35-45 km. In 2012/13 the SW began on December 25. The phase of its maximum development fell on the 1-4th of January when the stratopause altitude dropped on 30 km and the maximum temperature deviation from the model at this level reached 70K. In contrast to the first two warming (minor), the last was referred to the major type wherein air mass circulation change happened in the upper stratosphere over Tomsk ((http://www.geo.fu-berlin.de/en/met/ag/strat/index.html).).

  3. Ionospheric response to sudden stratospheric warming events at low and high solar activity

    NASA Astrophysics Data System (ADS)

    Fang, Tzu-Wei; Fuller-Rowell, Tim; Wang, Houjun; Akmaev, Rashid; Wu, Fei

    2014-09-01

    The sensitivity of the ionospheric response to a sudden stratospheric warming (SSW) event has been examined under conditions of low and high solar activity through simulations using the whole atmosphere model (WAM) and the global ionosphere plasmasphere model (GIP). During non-SSW conditions, simulated daytime mean vertical drifts at the magnetic equator show similar solar activity dependence as an empirical model. Model results of ionospheric total electron content (TEC) and equatorial vertical drift for the January 2009 major SSW, which occurred at very low solar activity conditions, show reasonable agreement with observations. The simulations demonstrate that the E region dynamo is capable of creating the semidiurnal variation of vertical drift. WAM and GIP were also run at high solar activity conditions, using the same lower atmosphere conditions as present in the January 2009 SSW event. The simulations indicate that the amplitude and phase of migrating tides in the dynamo region during the event have similar magnitudes for both solar flux conditions. However, comparing the ionospheric responses to a major SSW under low and high solar activity periods, it was found that the changes in the ionospheric vertical drifts and relative changes in TEC decreased with increasing solar activity. The simulations indicate that the F region dynamo becomes more important throughout the daytime and contributes to the upward drift in the afternoon during the event when the solar activity is higher. Our test simulations also confirm that the increase of the ionospheric conductivity associated with increasing solar activity is responsible for the decrease of vertical drift changes during an SSW. In particular, first, the increase in F region conductivity allows the closure of E region currents through the F region, reducing the polarization electric field before noon. Second, the F region dynamo contributes an upward drift postnoon, maintaining upward drifts till after sunset

  4. Stratospheric Sudden Warming Effects on the Ionospheric Migrating Tides during 2008-2010 observed by FORMOSAT-3/COSMIC

    NASA Astrophysics Data System (ADS)

    Lin, J.; Lin, C.; Chang, L. C.; Liu, H.; Chen, W.; Chen, C.; Liu, J. G.

    2013-12-01

    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 stratospheric sudden warming (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 stratospheric temperature increase. In addition to the amplitude changes of the tidal components, well matched phase shifts of the ionospheric migrating tides and the stratospheric 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.

  5. HALO aircraft measurements of East Asian anthropogenic SO2 import into the lower stratosphere by a warm conveyor belt uplift

    NASA Astrophysics Data System (ADS)

    Schlager, H.; Arnold, F.; Aufmhoff, H.; Baumann, R.; Pirjola, L.; Roiger, A.; Sailer, T.; Wirth, M.; Schumann, U.

    2012-04-01

    We report on a case study of anthropogenic SO2 pollution transport into the lower stratosphere 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 warm conveyor belt associated with a West-Pacific cyclone and finally injected into the lower stratosphere. 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 stratosphere presented in this study will be discussed.

  6. Relation between stratospheric sudden warming and the lunar effect on the equatorial electrojet based on Huancayo recordings

    NASA Astrophysics Data System (ADS)

    Adnan Siddiqui, Tarique; Lühr, Hermann; Stolle, Claudia; Park, Jaeheung

    2015-04-01

    It has been known for many decades that the lunar tidal influence in the equatorial electrojet (EEJ) is noticeably enhanced during northern hemisphere winters. Recent literature has discussed the role of stratospheric sudden warming (SSW) events behind the enhancement of lunar tides and their findings suggest a positive correlation between the lunar tidal amplitude and lower stratospheric parameters (zonal mean air temperature and zonal mean zonal wind) during SSW events. The positive correlation raises the question whether an inverse approach could also be developed which makes it possible to deduce the occurrence of SSW events before their direct observations (before 1952) from the amplitude of the lunar tides. This study presents an analysis technique based on the phase of the semi-monthly lunar tide to determine the lunar tidal modulation of the equatorial electrojet (EEJ). A statistical approach using the superposed epoch analysis is also carried out to formulate a relation between the EEJ tidal amplitude and lower stratospheric parameters. Using these results, we have estimated a threshold value for the tidal wave power that could be used to identify years with SSW events from magnetic field observations.

  7. Relation between stratospheric sudden warming and the lunar effect on the equatorial electrojet based on Huancayo recordings

    NASA Astrophysics Data System (ADS)

    Siddiqui, T. A.; Lühr, H.; Stolle, C.; Park, J.

    2015-02-01

    It has been known for many decades that the lunar tidal influence in the equatorial electrojet (EEJ) is noticeably enhanced during Northern Hemisphere winters. Recent literature has discussed the role of stratospheric sudden warming (SSW) events behind the enhancement of lunar tides and the findings suggest a positive correlation between the lunar tidal amplitude and lower stratospheric parameters (zonal mean air temperature and zonal mean zonal wind) during SSW events. The positive correlation raises the question whether an inverse approach could also be developed which makes it possible to deduce the occurrence of SSW events before their direct observations (before 1952) from the amplitude of the lunar tides. This study presents an analysis technique based on the phase of the semi-monthly lunar tide to determine the lunar tidal modulation of the EEJ. A statistical approach using the superposed epoch analysis is also carried out to formulate a relation between the EEJ tidal amplitude and lower stratospheric parameters. Using these results, we have estimated a threshold value for the tidal wave power that could be used to identify years with SSW events from magnetic field observations.

  8. Total Electron Content (TEC) disturbances over Brazilian region during the minor sudden stratospheric warming (SSW 2012) event of January 2012

    NASA Astrophysics Data System (ADS)

    Vieira, Francisco; Fagundes, Paulo Roberto; Kavutarapu, Venkatesh; Gil Pillat, Valdir

    2016-07-01

    The effects of Sudden Stratospheric Warming 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 stratospheric 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 stratospheric temperature peak. However, the Brazilian West sector was found to be more disturbed compared to the East sector during this SSW event.

  9. Dynamics of 2013 Sudden Stratospheric Warming event and its impact on cold weather over Eurasia: Role of planetary wave reflection.

    PubMed

    Nath, Debashis; Chen, Wen; Zelin, Cai; Pogoreltsev, Alexander Ivanovich; Wei, Ke

    2016-04-07

    In the present study, we investigate the impact of stratospheric planetary wave reflection on tropospheric weather over Central Eurasia during the 2013 Sudden Stratospheric Warming (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 stratospheric 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.

  10. Dynamics of 2013 Sudden Stratospheric Warming event and its impact on cold weather over Eurasia: Role of planetary wave reflection

    NASA Astrophysics Data System (ADS)

    Nath, Debashis; Chen, Wen; Zelin, Cai; Pogoreltsev, Alexander Ivanovich; Wei, Ke

    2016-04-01

    In the present study, we investigate the impact of stratospheric planetary wave reflection on tropospheric weather over Central Eurasia during the 2013 Sudden Stratospheric Warming (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 stratospheric 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.

  11. Dynamics of 2013 Sudden Stratospheric Warming event and its impact on cold weather over Eurasia: Role of planetary wave reflection

    PubMed Central

    Nath, Debashis; Chen, Wen; Zelin, Cai; Pogoreltsev, Alexander Ivanovich; Wei, Ke

    2016-01-01

    In the present study, we investigate the impact of stratospheric planetary wave reflection on tropospheric weather over Central Eurasia during the 2013 Sudden Stratospheric Warming (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 stratospheric 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

  12. Can the GEOS CCM Simulate the Temperature Response to Warm Pool El Nino Events in the Antarctic Stratosphere?

    NASA Technical Reports Server (NTRS)

    Hurwitz, M. M.; Song, I.-S.; Oman, L. D.; Newman, P. A.; Molod, A. M.; Frith, S. M.; Nielsen, J. E.

    2011-01-01

    "Warm 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 stratosphere. These conditions lead to higher polar stratospheric 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 warming 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.

  13. Can the GEOS CCM Simulate the Temperature Response to Warm Pool El Nino Events in the Antarctic Stratosphere?

    NASA Technical Reports Server (NTRS)

    Hurwitz, M. M.; Song, I.-S.; Oman, L. D.; Newman, P. A.; Molod, A. M.; Frith, S. M.; Nielsen, J. E.

    2010-01-01

    "Warm 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 stratosphere. These conditions lead to higher polar stratospheric 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 warming 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.

  14. Ionospheric disturbances in north eastern region of Asia during sudden stratospheric warming in January-February 2008

    NASA Astrophysics Data System (ADS)

    Kurkin, Vladimir; Medvedeva, Irina; Orlov, Igor; Pirog, Olga; Shpynev, Boris; Chernigovskaya, Marina

    This paper presents an investigation of the subauroral and mid-latitude ionosphere variations in the north eastern region of Asia from 18-th January until 17-th February, 2008. We used the data from network of vertical sounding ionosondes and Irkutsk incoherent scatter (IS) radar. To study small scales disturbances the observations using Irkutsk chirp-sounder and IS radar were conducted every 1 minute on 24-hour basis for 30 days. Vertical sounding stations operated in standard regime. To identify the stratospheric warming events the Berlin Meteorological University data (http://strat-www.met.fu-berlin.de) on stratospheric warming at standard isobaric levels and the atmospheric temperature height profiles measured by the Microwave Limb Sounder (MLS) aboard the EOS Aura spacecraft were used. Spectrums of multi-scale variations were derived from the data obtained during the prolonged experiment. We used the spectral analysis based on a modified Fourier transform with varying upper limit. The possible reasons of the ionospheric disturbances and their intensity spatial distribution are discussed. This work was supported by Russian Foundation for Basic Research (grant 08-05-00658).

  15. Comprehensive study of disturbances of the neutral atmosphere and ionosphere parameters over Eastern Siberia during major sudden stratospheric warming

    NASA Astrophysics Data System (ADS)

    Medvedeva, Irina; Medvedev, Andrey; Ratovsky, Konstantin; Tolstikov, Maxim; Shcherbakov, Alexander

    We investigated the disturbances of the neutral atmosphere and ionosphere parameters in a large range of heights in the region of Eastern Siberia during the period of the 2013 January sudden stratospheric warming (SSW). The analysis based on the data from spectrometric measurements of the OH and O2 upper atmospheric emissions obtained at the ISTP Geophysical Observatory (52E, 103N), data from Irkutsk DPS-4 Digisonde, data from Irkutsk Incoherent Scatter Radar, and satellite data on vertical temperature distribution in the atmosphere from Aura MLS v3.3. Also, the data of NCEP / NCAR and MERRA reanalysis were involved. The 2013 January major sudden stratospheric warming (SSW) was accompanied by significant disturbances of zonal characteristics of the lower and middle atmosphere, zonal circulation reversal at the 10-hPa level at 60N, and splitting of the polar vortex. Comprehensive analysis of the neutral atmosphere and ionosphere parameters revealed the SSW manifestations in a large height range. Disturbances of the neutral atmosphere temperature from the stratosphere to the mesosphere and lower thermosphere (MLT) were detected. At the MLT heights, revealed was an increase in the intensities of the OH (~87 km) and O2 (~94 km) emissions by a factor of 2-2.5 relative to the undisturbed conditions. At the F2-layer peak height, found were disturbances of the plasma parameters: electron density, electron and ion temperatures, and decrease in the daily rate of meridional component of the neutral wind. We assume that the observed effects can be caused by atmospheric circulation disturbances and amplification of vertical transfer. The disturbances in the upper atmosphere and ionosphere parameters during SSW can be evidence of the coupling between the lower and upper atmosphere. The work was supported by Russian Foundation for Basic Research Grant 13-05-00153 and RF President Grant of Public Support for RF Leading Scientific Schools (NSh-2942.2014.5).

  16. Stratospheric warmings in the Southern Hemisphere deduced from satellite radiation data, 1969-73

    NASA Technical Reports Server (NTRS)

    Quiroz, R. S.

    1974-01-01

    The investigation is largely based on radiation data from the vertical temperature profile radiometers on the satellite NOAA 2. The physical-statistical interpretation of the radiance data is considered. Aspects regarding the nonuniqueness of the minor warming in August 1973 are discussed. It is pointed out that conditions leading to major warmings in the Northern Hemisphere were not satisfied in the Southern Hemisphere during the period from 1969 to 1973.

  17. Rayleigh/raman Greenland Lidar Observations of Atmospheric Temperature During a Major Arctic Stratospheric Warming Event

    NASA Technical Reports Server (NTRS)

    Meriwether, John W.; Farley, Robert; Mcnutt, R.; Dao, Phan D.; Moskowitz, Warren P.

    1992-01-01

    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 stratosphere 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.

  18. Observations and simulations of midlatitude ionospheric and thermospheric response to the January 2013 stratospheric sudden warming event

    NASA Astrophysics Data System (ADS)

    Wu, Qian; Maute, A.; Yudin, V.; Goncharenko, L.; Noto, J.; Kerr, R.; Jacobi, Christoph

    2016-09-01

    Using observations from midlatitudes, we examine the ionospheric and thermospheric responses to the 2013 stratospheric sudden warming event by comparing data with four simulations performed by the Whole Atmosphere Community Climate Model eXtended (WACCM-X), Thermosphere-Ionosphere Mesosphere Electrodynamics General Circulation Model (TIMEGCM), and Thermosphere-Ionosphere Electrodynamics General Circulation Model (TIEGCM). The WACCM-X simulation was nudged by the GEOS-5 data. The two TIMEGCM simulations were nudged by the Modern-Era Retrospective analysis for Research and Applications data and by the aforementioned WACCM-X outputs, respectively. The standard TIEGCM simulation was also performed. These four simulations were compared with Millstone Hill (42.6°N, 71.4°W) incoherent scatter radar data, Millstone Hill and Boulder (40.1°N, 105.2°W) upper and lower thermospheric wind data. The meteor radar data from Collm (51.3°N, 13°E) were also used to examine the zonal wave number of the semidiurnal tide (SD). We evaluate the model simulations of the mesospheric and thermospheric responses to the 2013 SSW. The TIMEGCM simulation nudged with the WACCM-X output has suitable stratospheric input and ionospheric dynamics and can reproduce a sharp rise of hmf2 on January 12 observed by the Millstone Hill radar. The comparison of different models with the lower thermospheric SD tide yielded mixed results. The SD tide maintained mostly as a migrating tide for most of the time and matched the TIEGCM simulation very well. The WACCM-X appeared to perform better when the observed SD tide displays the large phase shift. It also has larger and more variable SD tide amplitude. The two TIMEGCM simulations have smaller SD amplitudes in general. Observations showed complex SD tide patterns after 20 January, which was difficult to characterize as a migrating tidal mode.

  19. TIME-GCM study of the ionospheric equatorial vertical drift changes during the 2006 stratospheric sudden warming

    NASA Astrophysics Data System (ADS)

    Maute, A.; Hagan, M. E.; Richmond, A. D.; Roble, R. G.

    2014-02-01

    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 stratospheric sudden warming (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 stratospheric 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.

  20. Daily Variations of Lower Thermospheric Tides at Middle Latitude and Their Association with Sudden Stratospheric Warming Events

    NASA Astrophysics Data System (ADS)

    Steeves, R.; Goncharenko, L. P.

    2013-12-01

    Sudden Stratospheric Warming (SSW) events have been shown by both observations and model results to couple the polar stratosphere to the low latitude ionosphere. Studies have suggested that a partial driver of the connection is the amplification of tides due to the SSW that reaches maximum at mid-latitudes. This study aims to increase the understanding of the coupling processes at mid-latitudes to establish possible SSW effects on dominant tidal structures. We utilize lower thermospheric (100-130 km) data collected from the Millstone Hill Incoherent Scatter Radar (ISR) (42.6N, 288.5E) during the Northern Hemispheric winter experimental campaigns classified as either SSW events or non-SSW events. The campaign set is comprised of two SSW events, one minor and one major, along with three non-SSW events. We also examine environmental characteristics such as temperature, zonal wind, and planetary wave activity (zonal wave numbers 1 and 2) from National Center for Environmental Prediction (NCEP) data for each campaign to distinguish any noteworthy characteristics. Comparison of the campaigns concentrates on the amplitudes and phases in the zonal and meridional winds. The altitudes of analysis lie in the range between 100 km and 124 km where the dominant tides were extracted at 3 km increments. Dominant tidal structures are the 12-hour tide and 6-hour tide, indicated by the Lomb-Scargle spectral analysis. The study focuses on these tides to show differences between campaigns and daily variations. A common trend found among the campaigns, both SSW and non-SSW events, is large day-to-day variability and evidence of oscillations with periods on the order of 2-4 days. Differences in phases show the most distinction between campaign subsets, especially in the meridional component.

  1. Total electron content disturbances during minor sudden stratospheric warming, over the Brazilian region: A case study during January 2012

    NASA Astrophysics Data System (ADS)

    Vieira, F.; Fagundes, P. R.; Venkatesh, K.; Goncharenko, L. P.; Pillat, V. G.

    2017-02-01

    The effects of sudden stratospheric warming (SSW) on ionosphere have been investigated by several scientists, using different observational techniques and model simulations. However, the minor SSW event during January 2012 is one of those that are less studied. Influences of several types of possible drivers—minor SSW event, changing solar flux, moderate geomagnetic storm on 22-25 January, and one of the largest solar proton events on 23-30 January—make it a challenging period to interpret. In the present study, the GPS-total electron content (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°) latitudes and 35°W and 65°W (30°) longitudes. Further, two chains of GPS receivers are used to study the response of the equatorial ionization anomaly (EIA) in the Brazilian eastern and western sectors, as well as its day-to-day variability before and during the SSW-2012. 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 the east and west sectors were weakened during the SSW-2012. However, the Brazilian eastern sector was found to be more disturbed compared to the western sector during this SSW-2012 event.

  2. Indirect global warming effects of ozone and stratospheric water vapor induced by surface methane emission

    SciTech Connect

    Wuebbles, D.J.; Grossman, A.S.; Tamaresis, J.S.; Patten, K.O. Jr.; Jain, A.; Grant, K.A.

    1994-07-01

    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 stratospheric 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%).

  3. Wave Driven Disturbances of the Thermal Structure in the Polar Winter Upper Stratosphere and Lower Mesosphere

    NASA Astrophysics Data System (ADS)

    Greer, Katelynn R.

    The polar winter middle atmosphere is a dynamically active region that is driven primarily by wave activity. Planetary waves intermittently disturbed the region at different levels and the most spectacular type of disturbance is a major Sudden Stratospheric Warming (SSW). However, other types of extreme disturbances occur on a more frequent, intraseasonal basis. One such disturbance is a synoptic-scale "weather event" observed in lidar and rocket soundings, soundings from the TIMED/SABER instrument and UK Meteorological Office (MetO) assimilated data. These disturbances are most easily identified near 42 km where temperatures are elevated over baseline conditions by a remarkable 50 K and an associated cooling is observed near 75 km. As these disturbances have a coupled vertical structure extending into the lower mesosphere, they are termed Upper Stratospheric/Lower Mesospheric (USLM) disturbances. This research begins with description of the phenomenology of USLM events in observations and the assimilated data set MetO, develops a description of the dynamics responsible for their development and places them in the context of the family of polar winter middle atmospheric disturbances. Climatologies indicates that USLM disturbances are commonly occurring polar wintertime disturbances of the middle atmosphere, have a remarkably repeating thermal structure, are located on the East side of the polar low and are related planetary wave activity. Using the same methodology for identifying USLM events and building climatologies of these events, the Whole Atmosphere Community Climate Model WACCM version 4 is established to spontaneously and internally generate USLM disturbances. Planetary waves are seen to break at a level just above the stratopause and convergence of the EP-flux vector is occurring in this region, decelerating the eastward zonal-mean wind and inducing ageostrophic vertical motion to maintain mass continuity. The descending air increases the horizontal

  4. Thermal and dynamical perturbations in the winter polar mesosphere-lower thermosphere region associated with sudden stratospheric warmings under conditions of low solar activity

    NASA Astrophysics Data System (ADS)

    Lukianova, Renata; Kozlovsky, Alexander; Shalimov, Sergey; Ulich, Thomas; Lester, Mark

    2015-06-01

    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 stratospheric warming (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 stratospheric maximum, and the mesospheric cooling is almost of the same value as the stratospheric warming (~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.

  5. Ionospheric Effects of Sudden Stratospheric Warming During Solar Maximum and Minimum Periods: What Do We See from Puerto Rico?

    NASA Astrophysics Data System (ADS)

    Hernandez-Espiet, A.; Goncharenko, L. P.; Spraggs, M. E.; Coster, A. J.; Galkin, I. A.; Aponte, N.

    2014-12-01

    Some of the main factors that contribute to changes in multiple ionospheric parameters are solar flux, geomagnetic activity, seasonal behavior, and coupling with lower atmosphere, which is particularly strong during sudden stratospheric warming events (SSW). Studying the way that these factors induce changes in the ionosphere is important, since these changes can have a negative effect on different types of communication systems. Multiple case studies have demonstrated large variations in ionospheric electron density in association with SSW in the low-latitude ionosphere, in particular near the crests of the equatorial ionization anomaly. However, the latitudinal extend of these variations was not addressed. In this study, we utilize data obtained in Puerto Rico by three instruments - Ramey digisonde, Arecibo Incoherent Scatter Radar (ISR) and GPS receivers to analyze four winter-time periods: two years with major SSW events (2005-2006, 2012-2013) and two years with minor SSW events (2006-2007, 2013-2014). In addition, selected cases represent two winters with low solar activity and two winters with moderate to high solar activity. The study focuses on the location of Arecibo, Puerto Rico (18.34°N, 66.75°W), ~15° to the north of the northern crest of the equatorial ionization anomaly. We report good agreement in ionospheric parameters between all three instruments. To investigate possible association with SSW events, we remove influences of seasonal behavior, solar flux, and geomagnetic activity by building empirical model and subtracting expected variations from the observational data. The analysis of residuals between the data and the model shows that ionospheric disturbances were observed in Puerto Rico for both minor and major SSW events in the ISR, digisonde and GPS Total Electron Content (TEC) data. We report 20-60% variations in NmF2 and TEC due to SSW effects. Large variations are also observed in electron density, electron temperature and plasma

  6. The influence of regional Arctic sea-ice decline on stratospheric and tropospheric circulation

    NASA Astrophysics Data System (ADS)

    McKenna, Christine; Bracegirdle, Thomas; Shuckburgh, Emily; Haynes, Peter

    2016-04-01

    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 stratospheric polar vortex and increase the frequency of sudden stratospheric warmings (SSWs). SSWs 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 stratosphere and does a good job of representing stratospheric 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

  7. Ionospheric Response to the 2009 Sudden Stratospheric Warming over the Equatorial, Low- and Mid-Latitudes in American Sector.

    NASA Astrophysics Data System (ADS)

    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.

    2014-12-01

    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 stratospheric warming (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

  8. A study of a self-generated stratospheric sudden warming and its mesospheric-lower thermospheric impacts using the coupled TIME-GCM/CCM3

    NASA Astrophysics Data System (ADS)

    Liu, H.-L.; Roble, R. G.

    2002-12-01

    A stratospheric sudden warming episode was self-consistently generated in the coupled National Center for Atmospheric Research Thermosphere, Ionosphere, Mesosphere, and Electrodynamics General Circulation Model/Climate Community Model version 3 (TIME-GCM/CCM3). Taking advantage of the unique vertical range of the coupled model (ground to 500 km), we were able to study the coupling of the lower and upper atmosphere in this warming episode. Planetary wave 1 is the dominant wave component in this warming event. Analysis of the wave phase structure and the wave amplitude indicates that the wave may experience resonant amplification prior to the peak warming. The mean wind in the high-latitude winter stratopause and mesosphere decelerates and reverses to westward due to planetary wave forcing and forms a critical layer near the zero wind lines. The wind deceleration and reversal also change the filtering of gravity waves by allowing more eastward gravity waves to propagate into the mesosphere and lower thermosphere (MLT), which causes eastward forcing and reverses the westward jet in the MLT. This also changes the meridional circulation in the upper mesosphere from poleward/downward to equatorward/upward, causing a depletion of the peak atomic oxygen layer at 97 km and significant reduction of green line airglow emission at high latitudes and midlatitudes. Planetary waves forced in situ by filtered gravity waves in the MLT grow in the warming episode. Their growth and interaction with tides create diurnal and semidiurnal variabilities in the zonal mean zonal wind.

  9. A three-dimensional analysis on the role of atmospheric waves in the climatology and interannual variability of stratospheric final warming in the Southern Hemisphere

    NASA Astrophysics Data System (ADS)

    Hirano, Soichiro; Kohma, Masashi; Sato, Kaoru

    2016-07-01

    Stratospheric final warming (SFW) in the Southern Hemisphere is examined in terms of their interannual variability and climatology using reanalysis data from January 1979 to March 2014. First, it is shown from a two-dimensional transformed Eulerian mean (TEM) analysis that a time-integrated vertical component of Eliassen-Palm flux during the spring is significantly related with SFW date. To clarify the role of residual mean flow in the interannual variability of the SFW date, SFWs are categorized into early and late groups according to the SFW date and their differences are examined. Significant difference in potential temperature tendency is observed in the middle and lower stratosphere in early October. Their structure in the meridional cross section accords well with that of vertical potential temperature advection by the residual mean flow. Difference in heating rate by shortwave radiation is minor. These results suggest that the adiabatic heating associated with the residual mean flow largely affects polar stratospheric temperature during austral spring and SFW date. The analysis is extended to investigate the longitudinal structure by using a three-dimensional (3-D) TEM theory. The significant difference in potential temperature tendency is mainly observed around the Weddell Sea at 10 hPa. Next, climatological 3-D structure of a vertical component of the residual mean flow in association with SFW is examined in terms of the effect on the troposphere. The results suggest that a downward residual mean flow from the stratosphere penetrates into underlying troposphere over East Antarctica and partly influences tropospheric temperature there.

  10. A mechanism to explain the variations of tropopause and tropopause inversion layer in the Arctic region during a sudden stratospheric warming in 2009

    NASA Astrophysics Data System (ADS)

    Wang, Rui; Tomikawa, Yoshihiro; Nakamura, Takuji; Huang, Kaiming; Zhang, Shaodong; Zhang, Yehui; Yang, Huigen; Hu, Hongqiao

    2016-10-01

    The mechanism to explain the variations of tropopause and tropopause inversion layer (TIL) in the Arctic region during a sudden stratospheric warming (SSW) in 2009 was studied with the Modern-Era Retrospective analysis for Research and Applications reanalysis data and GPS/Constellation Observing system for Meteorology, Ionosphere, and Climate (COSMIC) temperature data. During the prominent SSW in 2009, the cyclonic system changed to the anticyclonic system due to the planetary wave with wave number 2 (wave2). The GPS/COSMIC temperature data showed that during the SSW in 2009, the tropopause height in the Arctic decreased accompanied with the tropopause temperature increase and the TIL enhancement. The variations of the tropopause and TIL were larger in higher latitudes. A static stability analysis showed that the variations of the tropopause and TIL were associated with the variations of the residual circulation and the static stability due to the SSW. Larger static stability appeared in the upper stratosphere and moved downward to the narrow region just above the tropopause. The descent of strong downward flow was faster in higher latitudes. The static stability tendency analysis showed that the strong downward residual flow induced the static stability change in the stratosphere and around the tropopause. The strong downwelling in the stratosphere was mainly induced by wave2, which led to the tropopause height and temperature changes due to the adiabatic heating. Around the tropopause, a pair of downwelling above the tropopause and upwelling below the tropopause due to wave2 contributed to the enhancement of static stability in the TIL immediately after the SSW.

  11. Ground-Based Microwave Monitoring of Middle-Atmosphere Ozone Above Peterhof and Tomsk During Stratospheric Warming in the Winter of 2013-2014

    NASA Astrophysics Data System (ADS)

    Bochkovsky, D. A.; Virolainen, Ya. A.; Kulikov, Yu. Yu.; Marichev, V. N.; Poberovsky, A. V.; Ryskin, V. G.; Timofeyev, Yu. M.

    2016-09-01

    We present the results of studying the dynamics of middle-atmosphere ozone above Peterhof (60°N, 30°E) and Tomsk (56°N, 85°E) during stratospheric warming in the winter of 2013-2014 by the radiophysical method. In the ground-based observations we used the same microwave ozone meters (operated at 110.8 GHz) and the same techniques both for measuring the radiation spectra of ozone molecules and estimation of the vertical distribution of ozone in the middle atmosphere. These results were compared with satellite data on the total ozone content TOC (OMI/Aura), altitude profiles of ozone and temperature in the layer 20-60 km (MLS/Aura), and also with the data on ozone content in the layer 25-60 km, which were obtained using a Bruker IFS-125HR infrared Fourier spectrometer in Peterhof. Significant variations in ozone, which were caused by a stratospheric warming of the minor type, were observed in the atmosphere above Peterhof at altitudes of 40 to 60 km. The duration of dynamic perturbations above Peterhof was 2.5 months. Dynamic processes associated with the horizontal transport of air masses, which had an impact on the vertical structure of ozone in the middle atmosphere, were also detected above Tomsk, but this effect was less dependent on the background temperature variations.

  12. The record 2009 major stratospheric warming observed by lidar and millimeter-wave spectrometer at Thule (76.5° N, 68.8° W), Greenland

    NASA Astrophysics Data System (ADS)

    di Biagio, Claudia; Muscari, Giovanni; di Sarra, Alcide G.; Fiorucci, Irene; de Zafra, Robert L.; Cacciani, Marco; Eriksen, Paul; Fuà, Daniele

    2010-05-01

    The 2009 Arctic winter has been characterized by the largest major sudden stratospheric warming (SSW) event on record ever observed. In this study ground-based observations of the thermal structure and chemical composition of the middle atmosphere from the Network for Detection of Atmospheric Composition Change (NDACC) station at Thule (76.5° N, 68.8° W), Greenland, are used to show the evolution of the phenomenon in correspondence with the region of maximum warming. An intensive measurement campaign was conducted during January - early March 2009 at Thule with a lidar and a ground-based millimeter-wave spectrometer (GBMS). Lidar measurements permit to retrieve the atmospheric temperature profiles between 25 and 70 km with a vertical resolution of 150 m, and a 1σ uncertainty that varies from ~1 K at 25 km to ~15 K at the maximum probed altitude. Radiosonde data are used to derive temperatures below 25 km. GBMS measurements are used to derive O3, N2O, and CO concentration profiles between 15 and 55 km with a vertical resolution of ~7 km, and a 1σ uncertainty of 13%, 15%, and 16%, respectively. The GBMS retrieval algorithm has recently changed to a standard Optimal Estimation Method (OEM) which was applied to the O3 and N2O measurements. During the campaign, measurements were performed mostly on a daily basis, except during periods characterized by poor weather conditions or instrument malfunctioning. The temporal evolution of the measured temperature, T, has been derived at different potential temperature (?) levels between 300 (~10-12 km altitude) and 2000 K (~48-50 km altitude). Consistently with the typical SSW evolution, the warming affected the upper stratosphere first, and then propagated rapidly from the upper to the lower stratosphere. Before the warming event, in mid-January, the vortex was stably present and a PSC of NAT particles was detected by lidar on January 17 and 18 between 17 and 19 km altitude. The first signs of warming were observed at the

  13. Stratospheric ozone, global warming, and the principle of unintended consequences-An ongoing science and policy success story.

    PubMed

    Andersen, Stephen O; Halberstadt, Marcel L; Borgford-Parnell, Nathan

    2013-06-01

    In 1974, Mario Molina and F. Sherwood Rowland warned that chlorofluorocarbons (CFCs) could destroy the stratospheric 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 stratosphere 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 stratospheric 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 stratospheric 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. [Box

  14. Stratospheric ozone, global warming, and the principle of unintended consequences--an ongoing science and policy success story.

    PubMed

    Andersen, Stephen O; Halberstadt, Marcel L; Borgford-Parnell, Nathan

    2013-06-01

    In 1974, Mario Molina and F. Sherwood Rowland warned that chlorofluorocarbons (CFCs) could destroy the stratospheric 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 stratosphere 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 stratospheric 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 stratospheric 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.

  15. Study of the thermospheric and ionospheric response to the 2009 sudden stratospheric warming using TIME-GCM and GSM TIP models: First results

    NASA Astrophysics Data System (ADS)

    Klimenko, M. V.; Klimenko, V. V.; Bessarab, F. S.; Korenkov, Yu N.; Liu, Hanli; Goncharenko, L. P.; Tolstikov, M. V.

    2015-09-01

    This paper presents a study of mesosphere and low thermosphere influence on ionospheric disturbances during 2009 major sudden stratospheric warming (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 stratospheric 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.

  16. Ionospheric response to the 2006 sudden stratospheric warming event over the equatorial and low latitudes in the Brazilian sector using GPS observations

    NASA Astrophysics Data System (ADS)

    de Jesus, R.; Batista, I. S.; Fagundes, P. R.; Venkatesh, K.; de Abreu, A. J.

    2017-02-01

    The main purpose of this paper is to study the response of the ionospheric F-region using GPS-TEC measurements at equatorial and low latitude regions over the Brazilian sector during an sudden stratospheric warming (SSW) event in the year 2006. In this work, we present vertical total electron content (VTEC) and phase fluctuations derived from GPS network in Brazil. The continuous wavelet transform (CWT) was employed to check the periodicities of the ∆VTEC during the SSW event. The results show a strong decrease in VTEC and ∆VTEC values in the afternoon over low latitudes from DOY 05-39 (during the SSW event) mainly after the second SSW temperature peak. The ionospheric ∆VTEC pattern over Brazilian sector shows diurnal and semidiurnal oscillations during the 2006 SSW event. In addition, for the first time, variations in ∆VTEC (low latitude stations) with periods of about 02-08 day have been reported during an SSW event. Using GPS stations located in the Brazilian sector, it is reported for the first time that equatorial ionospheric irregularities were not suppressed by the SSW event.

  17. Impacts of stratospheric ozone depletion and recovery on wave propagation in the boreal winter stratosphere

    NASA Astrophysics Data System (ADS)

    Hu, Dingzhu; Tian, Wenshou; Xie, Fei; Wang, Chunxiao; Zhang, Jiankai

    2015-08-01

    This paper uses a state-of-the-art general circulation model to study the impacts of the stratospheric 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 stratospheric ozone depletion leads to a cooler and stronger Antarctic stratosphere, while the stratospheric ozone recovery has the opposite effects. In the Northern Hemisphere (NH), the impacts of the stratospheric ozone depletion on polar stratospheric temperature are not opposite to that of the stratospheric ozone recovery; i.e., the stratospheric ozone depletion causes a weak cooling and the stratospheric ozone recovery causes a statistically significant cooling. The stratospheric ozone depletion leads to a weakening of the Arctic polar vortex, while the stratospheric 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 stratospheric ozone increases. Particularly interesting is that stratospheric ozone changes have opposite effects on the stationary and transient wave fluxes in the NH stratosphere. The analysis of the wave refractive index and Eliassen-Palm flux in the NH indicates (1) that the wave refraction in the stratosphere cannot fully explain wave flux changes in the Arctic stratosphere and (2) that stratospheric ozone changes can cause changes in wave propagation in the northern midlatitude troposphere which in turn affect wave fluxes in the NH stratosphere. In the SH, the radiative cooling (warming) caused by stratospheric 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

  18. Stratospheric chemistry

    SciTech Connect

    Brune, W.H. )

    1991-01-01

    Advances in stratospheric chemistry made by investigators in the United States from 1987 to 1990 are reviewed. Subject areas under consideration include photochemistry of the polar stratosphere, photochemistry of the global stratosphere, and assessments of inadvertent modification of the stratosphere 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 stratospheric ozone, and reactive nitrogen effects.

  19. How Much Winter Stratospheric Polar-cap Warming Is Explained By Upward-propagating Planetary Waves In CMIP5 Models?: Part 1. An Indirect Approach Using A Wave Interference Index

    NASA Astrophysics Data System (ADS)

    Kim, J.; Kim, B.

    2013-12-01

    The breaking of upward-propagating planetary (typically characterized by the combination of zonal wave number 1 and 2) waves in the stratosphere is regarded as one of the factors that provoke the sudden stratospheric warming (SSW) and the accompanying collapse of stratospheric 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 stratosphere 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

  20. Stratospheric control of planetary waves

    NASA Astrophysics Data System (ADS)

    Hitchcock, Peter; Haynes, Peter H.

    2016-11-01

    The effects of imposing at various altitudes in the stratosphere zonally symmetric circulation anomalies associated with a stratospheric sudden warming are investigated in a mechanistic circulation model. A shift of the tropospheric jet is found even when the anomalies are imposed only above 2 hPa. Their influence is communicated downward through the planetary wave field via three distinct mechanisms. First, a significant fraction of the amplification of the upward fluxes of wave activity prior to the central date of the warming is due to the coupled evolution of the stratospheric zonal mean state and the wave field throughout the column. Second, a downward propagating region of localized wave, mean-flow interaction is active around the central date but does not penetrate the tropopause. Third, there is deep, vertically synchronous suppression of upward fluxes following the central date. The magnitude of this suppression correlates with that of the tropospheric jet shift.

  1. Stratospheric aerosol geoengineering

    SciTech Connect

    Robock, Alan

    2015-03-30

    The Geoengineering Model Intercomparison Project, conducting climate model experiments with standard stratospheric 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 warm, 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 warming. 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 warming.

  2. The stratosphere

    NASA Astrophysics Data System (ADS)

    Taylor, F. W.

    2003-01-01

    The stratosphere is that part of the atmosphere which lies between ca.10 and 50 km above the surface of the Earth and which contains the ozone layer. It is the seat of much interesting behaviour in terms of dynamics, radiation and chemistry, now revealed in detail by observations from modern space instruments, but still not completely understood. Other planetary atmospheres exhibit stratospheric behaviour which in some ways resembles, and in others contrasts sharply with, that of the Earth. In reviewing these topics, this paper describes some key problems that will be addressed by new measurements from space in the near future.

  3. The stratosphere.

    PubMed

    Taylor, F W

    2003-01-15

    The stratosphere is that part of the atmosphere which lies between ca. 10 and 50 km above the surface of the Earth and which contains the ozone layer. It is the seat of much interesting behaviour in terms of dynamics, radiation and chemistry, now revealed in detail by observations from modern space instruments, but still not completely understood. Other planetary atmospheres exhibit stratospheric behaviour which in some ways resembles, and in others contrasts sharply with, that of the Earth. In reviewing these topics, this paper describes some key problems that will be addressed by new measurements from space in the near future.

  4. Atmospheric responses to stratospheric aerosol geoengineering

    NASA Astrophysics Data System (ADS)

    Ferraro, Angus; Highwood, Eleanor; Charlton-Perez, Andrew

    2013-04-01

    Stratospheric aerosol geoengineering, also called solar radiation management (SRM), involves the injection of aerosol into the stratosphere to increase the planetary albedo. It has been conceieved as a policy option in response to human-induced global warming. It is well-established from modelling studies and observations following volcanic eruptions that stratospheric sulphate aerosols cause global cooling. Some aspects of the climate response, especially those involving large-scale dynamical changes, are more uncertain. This work attempts to identify the physical mechanisms operating in the climate response to stratospheric aerosol geoengineering using idealised model experiments. The radiative forcing produced by the aerosol depends on its type (species) and size. Aerosols absorb terrestrial and solar radiation, which drives stratospheric temperature change. The stratospheric temperature change also depends on aerosol type and size. We calculate the stratospheric temperature change due to geoengineering with sulphate, titania, limestone and soot in a fixed-dynamical-heating radiative model. Sulphate produces tropical heating of up to ~6 K. Titania produces much less heating, whereas soot produces much more. Most aerosols increase the meridional temperature gradient in the lower stratosphere which, by thermal wind balance, would be expected to intensify the zonal winds in the polar vortex. An intermediate-complexity general circulation model is used to investigate the dynamical response to geoengineering aerosols. Atmospheric carbon dioxide concentrations are quadrupled. The carbon dioxide forcing is then balanced using stratospheric sulphate aerosol. We assess dynamical changes in the stratosphere, for example, the frequency of stratospheric sudden warmings and the strength of the Brewer-Dobson overturning circulation. We also assess changes in the strength and position of the tropospheric jets. We compare results for sulphate with those for titania.

  5. Stratospheric ozone depletion

    PubMed Central

    Rowland, F. Sherwood

    2006-01-01

    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 warms the air, creating the stratosphere 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 stratospheric ozone layer. The growing emissions of synthetic chlorofluorocarbon molecules cause a significant diminution in the ozone content of the stratosphere, 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 stratosphere 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

  6. Stratospheric ozone depletion.

    PubMed

    Rowland, F Sherwood

    2006-05-29

    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 warms the air, creating the stratosphere 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 stratospheric ozone layer. The growing emissions of synthetic chlorofluorocarbon molecules cause a significant diminution in the ozone content of the stratosphere, 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 stratosphere 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.

  7. The Future of the Stratosphere and the Ozone Layer

    NASA Astrophysics Data System (ADS)

    Newman, P. A.; Oman, L.; Pawson, S.; Fleming, E. L.; Li, F.; Jackman, C. H.

    2014-12-01

    Stratospheric 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 stratospheric 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 stratospheric circulation and chemistry changes induced by Greenhouse Gas increases (the "GHG era"). The stratosphere 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 stratospheric ozone levels and the basic stratospheric climatology: CO2 and CH4 increases will increase stratospheric ozone, while N2O increases will decrease stratospheric ozone. In particular, GHG increases and the associated warming of the troposphere will modify stratospheric transport and cool the upper stratosphere. 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 stratosphere evolves under future GHG projections from the various Representative Concentration Pathways, illustrating the different changes in stratospheric ozone caused by the concurrent radiative, chemical and dynamical impacts of GHG changes.

  8. Numerical Experiments on the Stratospheric-Tropospheric Dynamical Interaction.

    DTIC Science & Technology

    1980-04-11

    influence of stratospheric conditions which are representative of a sudden warm- ing on tropospheric weather. Quiroz (1977), McGuirk (1978), and O’Neill and...1979, 155-160. Quiroz , R. S.: 1977, The tropospheric-stratospheric polar vortex breakdown of January 1977. Geophvs. Res. Lett., 4, 151-154. Schoeberl, M

  9. Stratospheric aircraft: Impact on the stratosphere

    SciTech Connect

    Johnston, H.

    1992-02-01

    The steady-state distribution of natural stratospheric 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 stratosphere. Nitrogen oxides from the exhausts of a commercially viable fleet of supersonic transports would exceed the natural source of stratospheric 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 stratospheric 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 stratospheric 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 stratosphere, 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 stratosphere and to broaden our knowledge of hetergeneous stratospheric chemistry. This article reviews recently proposed new mechanisms for heterogeneous reactions on the global stratospheric sulfate aerosols.

  10. Stratospheric aircraft: Impact on the stratosphere?

    SciTech Connect

    Johnston, H.

    1992-02-01

    The steady-state distribution of natural stratospheric 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 stratosphere. Nitrogen oxides from the exhausts of a commercially viable fleet of supersonic transports would exceed the natural source of stratospheric 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 stratospheric 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 stratospheric 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 stratosphere, 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 stratosphere and to broaden our knowledge of hetergeneous stratospheric chemistry. This article reviews recently proposed new mechanisms for heterogeneous reactions on the global stratospheric sulfate aerosols.

  11. Atmospheric science: stratospheric cooling and the troposphere.

    PubMed

    Gillett, Nathan P; Santer, Benjamin D; Weaver, Andrew J

    2004-12-02

    Satellite observations of tropospheric temperatures seem to show less warming than surface temperatures, contrary to physical predictions. Fu et al. show that statistical correction for the effect of stratospheric cooling brings the satellite-based estimates of tropospheric warming into closer agreement with observations of surface warming. Here we apply the method of Fu et al. to output from a state-of-the-art coupled climate model and show that simulated tropospheric temperature trends are consistent with those observed and that their method is robust.

  12. Stratospheric Response to Intraseasonal Changes in Incoming Solar Radiation

    NASA Astrophysics Data System (ADS)

    Garfinkel, Chaim; silverman, vered; harnik, nili; Erlich, caryn

    2016-04-01

    Superposed epoch analysis of meteorological reanalysis data is used to demonstrate a significant connection between intraseasonal solar variability and temperatures in the stratosphere. Decreasing solar flux leads to a cooling of the tropical upper stratosphere above 7hPa, while increasing solar flux leads to a warming of the tropical upper stratosphere above 7hPa, after a lag of approximately six to ten days. Late winter (February-March) Arctic stratospheric 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 warms 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 warming during the easterly phase). The estimated composite mean changes in Northern Hemisphere upper stratospheric (~ 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 stratosphere. Garfinkel, C.I., V. Silverman, N. Harnik, C. Erlich, Y. Riz (2015), Stratospheric Response to Intraseasonal Changes in Incoming Solar Radiation, J. Geophys. Res. Atmos., 120, 7648-7660. doi: 10.1002/2015JD023244.

  13. Weakened stratospheric quasibiennial oscillation driven by increased tropical mean upwelling.

    PubMed

    Kawatani, Yoshio; Hamilton, Kevin

    2013-05-23

    The zonal wind in the tropical stratosphere switches between prevailing easterlies and westerlies with a period of about 28 months. In the lowermost stratosphere, the vertical structure of this quasibiennial oscillation (QBO) is linked to the mean upwelling, which itself is a key factor in determining stratospheric composition. Evidence for changes in the QBO have until now been equivocal, raising questions as to the extent of stratospheric circulation changes in a global warming 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 stratosphere. 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 warming 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 stratosphere. Almost all comprehensive climate models have projected an intensifying tropical upwelling in global warming 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-stratosphere QBO amplitude provides strong support for the existence of a long-term trend of enhanced upwelling near the tropical tropopause.

  14. Global Warming: Lessons from Ozone Depletion

    ERIC Educational Resources Information Center

    Hobson, Art

    2010-01-01

    My teaching and textbook have always covered many physics-related social issues, including stratospheric ozone depletion and global warming. The ozone saga is an inspiring good-news story that's instructive for solving the similar but bigger problem of global warming. Thus, as soon as students in my physics literacy course at the University of…

  15. Significant radiative impact of volcanic aerosol in the lowermost stratosphere.

    PubMed

    Andersson, Sandra M; Martinsson, Bengt G; Vernier, Jean-Paul; Friberg, Johan; Brenninkmeijer, Carl A M; Hermann, Markus; van Velthoven, Peter F J; Zahn, Andreas

    2015-07-09

    Despite their potential to slow global warming, until recently, the radiative forcing associated with volcanic aerosols in the lowermost stratosphere (LMS) had not been considered. Here we study volcanic aerosol changes in the stratosphere 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 stratosphere aerosol loadings, whereas the Southern Hemisphere generally had loadings close to background conditions. We show that half of the global stratospheric aerosol optical depth following the Kasatochi, Sarychev and Nabro eruptions is attributable to LMS aerosol. On average, 30% of the global stratospheric 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.

  16. Studying Stratospheric Temperature Variation with Cosmic Ray Measurements

    NASA Astrophysics Data System (ADS)

    Zhang, Xiaohang; He, Xiaochun

    2015-04-01

    The long term stratospheric cooling in recent decades is believed to be equally important as surface warming as evidence of influences of human activities on the climate system. Un- fortunatly, there are some discrepancies among different measurements of stratospheric 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 stratospheric 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 stratospheric temperature will be discussed. We verify this method by comparing the stratospheric tem- perature measured by radiosonde with the ones derived from cosmic ray measurement at multiple locations around the globe.

  17. Significant radiative impact of volcanic aerosol in the lowermost stratosphere

    PubMed Central

    Andersson, Sandra M.; Martinsson, Bengt G.; Vernier, Jean-Paul; Friberg, Johan; Brenninkmeijer, Carl A. M.; Hermann, Markus; van Velthoven, Peter F. J.; Zahn, Andreas

    2015-01-01

    Despite their potential to slow global warming, until recently, the radiative forcing associated with volcanic aerosols in the lowermost stratosphere (LMS) had not been considered. Here we study volcanic aerosol changes in the stratosphere 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 stratosphere aerosol loadings, whereas the Southern Hemisphere generally had loadings close to background conditions. We show that half of the global stratospheric aerosol optical depth following the Kasatochi, Sarychev and Nabro eruptions is attributable to LMS aerosol. On average, 30% of the global stratospheric 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

  18. Transport of ice into the stratosphere and the humidification of the stratosphere over the 21st century

    NASA Astrophysics Data System (ADS)

    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.

    2016-03-01

    Climate models predict that tropical lower stratospheric humidity will increase as the climate warms. We examine this trend in two state-of-the-art chemistry-climate models. Under high greenhouse gas emissions scenarios, the stratospheric 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 warming 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 stratosphere. 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 stratospheric humidity. Assessing the ability of models to realistically represent ice lofting processes should be a high priority in the modeling community.

  19. Transport of Ice into the Stratosphere and the Humidification of the Stratosphere over the 21st Century

    NASA Technical Reports Server (NTRS)

    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.

    2016-01-01

    Climate models predict that tropical lower-stratospheric humidity will increase as the climate warms. We examine this trend in two state-of-the-art chemistry-climate models. Under high greenhouse gas emissions scenarios, the stratospheric entry value of water vapor increases by approx. 1 part per million by volume (ppmv) over this century in both models. We show with trajectory runs driven by model meteorological fields that the warming 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 stratosphere. 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 stratospheric humidity. Assessing the ability of models to realistically represent ice-lofting processes should be a high priority in the modeling community.

  20. Downward-Propagating Temperature Anomalies in the Preconditioned Polar Stratosphere.

    NASA Astrophysics Data System (ADS)

    Zhou, Shuntai; Miller, Alvin J.; Wang, Julian; Angell, James K.

    2002-04-01

    Dynamical links of the Northern Hemisphere stratosphere and troposphere are studied, with an emphasis on whether stratospheric changes have a direct effect on tropospheric weather and climate. In particular, downward propagation of stratospheric anomalies of polar temperature in the winter-spring season is examined based upon 22 years of NCEP-NCAR reanalysis data. It is found that the polar stratosphere is sometimes preconditioned, which allows a warm anomaly to propagate from the upper stratosphere to the troposphere, and sometimes it prohibits downward propagation. The Arctic Oscillation (AO) is more clearly seen in the former case. To understand what dynamical conditions dictate the stratospheric property of downward propagation, the upper-stratospheric warming episodes with very large anomalies (such as stratospheric sudden warming) are selected and divided into two categories according to their downward-propagating features. Eliassen-Palm (E-P) diagnostics and wave propagation theories are used to examine the characteristics of wave-mean flow interactions in the two different categories. It is found that in the propagating case the initial wave forcing is very large and the polar westerly wind is reversed. As a result, dynamically induced anomalies propagate down as the critical line descends. A positive feedback is that the dramatic change in zonal wind alters the refractive index in a way favorable for continuous poleward transport of wave energy. The second pulse of wave flux conducts polar warm anomalies farther down. Consequently, the upper-tropospheric circulations are changed, in particular, the subtropical North Atlantic jet stream shifts to the south by 5 degrees of latitude, and the alignment of the jet stream becomes more zonal, which is similar to the negative phase of the North Atlantic Oscillation (NAO).

  1. Weather from the Stratosphere?

    NASA Technical Reports Server (NTRS)

    Baldwin, Mark P.; Thompson, David W. J.; Shuckburgh, Emily F.; Norton, Warwick A.; Gillett, Nathan P.

    2006-01-01

    Is the stratosphere, the atmospheric layer between about 10 and 50 km, important for predicting changes in weather and climate? The traditional view is that the stratosphere 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 stratosphere 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 stratosphere above it is less dense and less turbulent (see the figure). Variability in the stratosphere is dominated by hemispheric-scale changes in airflow on time scales of a week to several months. Occasionally, however, stratospheric 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 stratosphere mainly through atmospheric waves that propagate upward. Recent evidence shows that the stratosphere organizes this chaotic wave forcing from below to create long-lived changes in the stratospheric circulation. These stratospheric changes can feed back to affect weather and climate in the troposphere.

  2. How stratospheric are deep stratospheric intrusions?

    NASA Astrophysics Data System (ADS)

    Trickl, T.; Vogelmann, H.; Giehl, H.; Scheel, H.-E.; Sprenger, M.; Stohl, A.

    2014-06-01

    Preliminary attempts of quantifying the stratospheric ozone contribution in the observations at the Zugspitze summit (2962 m a.s.l.) next to Garmisch-Partenkirchen in the German Alps had yielded an approximate doubling of the stratospheric fraction of the Zugspitze ozone during the time period 1978 and 2004. These investigations had been based on data filtering by using low relative humidity and elevated 7Be as the criteria for selecting half-hour intervals of ozone data representative of stratospheric intrusion air. For quantifying the residual stratospheric component in stratospherically influenced air masses, however, the mixing of tropospheric air into the stratospheric intrusion layers must be taken into account. In fact, the dew-point-mirror instrument at the Zugspitze summit station rarely registers relative humidity (RH) values lower than 10% in stratospheric air intrusions. Since 2007 a programme of routine lidar sounding of ozone, water vapour and aerosol has been conducted in the Garmisch-Partenkirchen area. The lidar results demonstrate that the intrusion layers are dryer by roughly one order of magnitude than indicated in the in-situ measurements. Even in thin layers frequently RH values clearly below 1% have been observed. These thin, undiluted layers present an important challenge for atmospheric modelling. Although the ozone values never reach values typical of the lower-stratosphere it becomes, thus, obvious that, without strong wind shear or convective processes, mixing of stratospheric and tropospheric air must be very slow in most of the free troposphere. As a consequence, the analysis the Zugspitze data can be assumed to be more reliable than anticipated. Finally, the concentrations of Zugspitze carbon monoxide rarely drop inside intrusion layers and normally stay clearly above full stratospheric values. This indicates that most of the CO and, thus, the intrusion air mass originate in the shallow "mixing layer" around the thermal tropopause

  3. How stratospheric are deep stratospheric intrusions?

    NASA Astrophysics Data System (ADS)

    Trickl, T.; Vogelmann, H.; Giehl, H.; Scheel, H.-E.; Sprenger, M.; Stohl, A.

    2014-09-01

    Preliminary attempts of quantifying the stratospheric ozone contribution in the observations at the Zugspitze summit (2962 m a.s.l.) next to Garmisch-Partenkirchen in the German Alps had yielded an approximate doubling of the stratospheric fraction of the Zugspitze ozone during the time period 1978 to 2004. These investigations had been based on data filtering by using low relative humidity (RH) and elevated 7Be as the criteria for selecting half-hour intervals of ozone data representative of stratospheric intrusion air. To quantify the residual stratospheric component in stratospherically influenced air masses, however, the mixing of tropospheric air into the stratospheric intrusion layers must be taken into account. In fact, the dewpoint mirror instrument at the Zugspitze summit station rarely registers RH values lower than 10% in stratospheric air intrusions. Since 2007 a programme of routine lidar sounding of ozone, water vapour and aerosol has been conducted in the Garmisch-Partenkirchen area. The lidar results demonstrate that the intrusion layers are drier by roughly one order of magnitude than indicated in the in situ measurements. Even in thin layers RH values clearly below 1% have frequently been observed. These thin, undiluted layers present an important challenge for atmospheric modelling. Although the ozone values never reach values typical of the lower-stratosphere it becomes, thus, obvious that, without strong wind shear or convective processes, mixing of stratospheric and tropospheric air must be very slow in most of the free troposphere. As a consequence, the analysis the Zugspitze data can be assumed to be more reliable than anticipated. Finally, the concentrations of Zugspitze carbon monoxide rarely drop inside intrusion layers and normally stay clearly above full stratospheric values. This indicates that most of the CO, and thus the intrusion air mass, originates in the shallow "mixing layer" around the thermal tropopause. The CO mixing ratio in

  4. Benefits, risks, and costs of stratospheric geoengineering

    NASA Astrophysics Data System (ADS)

    Robock, Alan; Marquardt, Allison; Kravitz, Ben; Stenchikov, Georgiy

    2009-10-01

    Injecting sulfate aerosol precursors into the stratosphere has been suggested as a means of geoengineering to cool the planet and reduce global warming. The decision to implement such a scheme would require a comparison of its benefits, dangers, and costs to those of other responses to global warming, including doing nothing. Here we evaluate those factors for stratospheric geoengineering with sulfate aerosols. Using existing U.S. military fighter and tanker planes, the annual costs of injecting aerosol precursors into the lower stratosphere would be several billion dollars. Using artillery or balloons to loft the gas would be much more expensive. We do not have enough information to evaluate more exotic techniques, such as pumping the gas up through a hose attached to a tower or balloon system. Anthropogenic stratospheric aerosol injection would cool the planet, stop the melting of sea ice and land-based glaciers, slow sea level rise, and increase the terrestrial carbon sink, but produce regional drought, ozone depletion, less sunlight for solar power, and make skies less blue. Furthermore it would hamper Earth-based optical astronomy, do nothing to stop ocean acidification, and present many ethical and moral issues. Further work is needed to quantify many of these factors to allow informed decision-making.

  5. The contribution of ozone to future stratospheric temperature trends

    NASA Astrophysics Data System (ADS)

    Maycock, A. C.

    2016-05-01

    The projected recovery of ozone from the effects of ozone depleting substances this century will modulate the stratospheric cooling due to CO2, thereby affecting the detection and attribution of stratospheric temperature trends. Here the impact of future ozone changes on stratospheric 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 stratospheric 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 warming of the upper and lower stratosphere. The misspecification of ozone trends for RCP2.6/RCP4.5 in models that used the International Global Atmospheric Chemistry (IGAC)/Stratosphere-troposphere Processes and their Role in Climate (SPARC) Ozone Database causes anomalous warming (cooling) of the upper (lower) stratosphere compared to chemistry-climate models. The dependence of ozone chemistry on greenhouse gas concentrations should therefore be better represented in CMIP6.

  6. Climate and Ozone Response to Increased Stratospheric Water Vapor

    NASA Technical Reports Server (NTRS)

    Shindell, Drew T.

    2001-01-01

    Stratospheric water vapor abundance affects ozone, surface climate, and stratospheric 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 stratospheric water vapor is allowed to increase. Observations suggest that stratospheric 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 stratosphere, suggesting that ongoing climate change may be altering tropospheric input. The calculated stratospheric water vapor increase contributes an additional approximately equals 24% (approximately equals 0.2 W/m(exp 2)) to the global warming 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 warming and impede stratospheric ozone recovery.

  7. Stratospheric solar geoengineering without ozone loss.

    PubMed

    Keith, David W; Weisenstein, Debra K; Dykema, John A; Keutsch, Frank N

    2016-12-27

    Injecting sulfate aerosol into the stratosphere, the most frequently analyzed proposal for solar geoengineering, may reduce some climate risks, but it would also entail new risks, including ozone loss and heating of the lower tropical stratosphere, which, in turn, would increase water vapor concentration causing additional ozone loss and surface warming. We propose a method for stratospheric aerosol climate modification that uses a solid aerosol composed of alkaline metal salts that will convert hydrogen halides and nitric and sulfuric acids into stable salts to enable stratospheric geoengineering while reducing or reversing ozone depletion. Rather than minimizing reactive effects by reducing surface area using high refractive index materials, this method tailors the chemical reactivity. Specifically, we calculate that injection of calcite (CaCO3) aerosol particles might reduce net radiative forcing while simultaneously increasing column ozone toward its preanthropogenic baseline. A radiative forcing of -1 W⋅m(-2), for example, might be achieved with a simultaneous 3.8% increase in column ozone using 2.1 Tg⋅y(-1) of 275-nm radius calcite aerosol. Moreover, the radiative heating of the lower stratosphere would be roughly 10-fold less than if that same radiative forcing had been produced using sulfate aerosol. Although solar geoengineering cannot substitute for emissions cuts, it may supplement them by reducing some of the risks of climate change. Further research on this and similar methods could lead to reductions in risks and improved efficacy of solar geoengineering methods.

  8. Stratospheric solar geoengineering without ozone loss

    PubMed Central

    Weisenstein, Debra K.; Dykema, John A.; Keutsch, Frank N.

    2016-01-01

    Injecting sulfate aerosol into the stratosphere, the most frequently analyzed proposal for solar geoengineering, may reduce some climate risks, but it would also entail new risks, including ozone loss and heating of the lower tropical stratosphere, which, in turn, would increase water vapor concentration causing additional ozone loss and surface warming. We propose a method for stratospheric aerosol climate modification that uses a solid aerosol composed of alkaline metal salts that will convert hydrogen halides and nitric and sulfuric acids into stable salts to enable stratospheric geoengineering while reducing or reversing ozone depletion. Rather than minimizing reactive effects by reducing surface area using high refractive index materials, this method tailors the chemical reactivity. Specifically, we calculate that injection of calcite (CaCO3) aerosol particles might reduce net radiative forcing while simultaneously increasing column ozone toward its preanthropogenic baseline. A radiative forcing of −1 W⋅m−2, for example, might be achieved with a simultaneous 3.8% increase in column ozone using 2.1 Tg⋅y−1 of 275-nm radius calcite aerosol. Moreover, the radiative heating of the lower stratosphere would be roughly 10-fold less than if that same radiative forcing had been produced using sulfate aerosol. Although solar geoengineering cannot substitute for emissions cuts, it may supplement them by reducing some of the risks of climate change. Further research on this and similar methods could lead to reductions in risks and improved efficacy of solar geoengineering methods. PMID:27956628

  9. Stratospheric solar geoengineering without ozone loss

    NASA Astrophysics Data System (ADS)

    Keith, David W.; Weisenstein, Debra K.; Dykema, John A.; Keutsch, Frank N.

    2016-12-01

    Injecting sulfate aerosol into the stratosphere, the most frequently analyzed proposal for solar geoengineering, may reduce some climate risks, but it would also entail new risks, including ozone loss and heating of the lower tropical stratosphere, which, in turn, would increase water vapor concentration causing additional ozone loss and surface warming. We propose a method for stratospheric aerosol climate modification that uses a solid aerosol composed of alkaline metal salts that will convert hydrogen halides and nitric and sulfuric acids into stable salts to enable stratospheric geoengineering while reducing or reversing ozone depletion. Rather than minimizing reactive effects by reducing surface area using high refractive index materials, this method tailors the chemical reactivity. Specifically, we calculate that injection of calcite (CaCO3) aerosol particles might reduce net radiative forcing while simultaneously increasing column ozone toward its preanthropogenic baseline. A radiative forcing of ‑1 Wṡm‑2, for example, might be achieved with a simultaneous 3.8% increase in column ozone using 2.1 Tgṡy‑1 of 275-nm radius calcite aerosol. Moreover, the radiative heating of the lower stratosphere would be roughly 10-fold less than if that same radiative forcing had been produced using sulfate aerosol. Although solar geoengineering cannot substitute for emissions cuts, it may supplement them by reducing some of the risks of climate change. Further research on this and similar methods could lead to reductions in risks and improved efficacy of solar geoengineering methods.

  10. Stratospheric water vapor feedback.

    PubMed

    Dessler, A E; Schoeberl, M R; Wang, T; Davis, S M; Rosenlof, K H

    2013-11-05

    We show here that stratospheric water vapor variations play an important role in the evolution of our climate. This comes from analysis of observations showing that stratospheric water vapor increases with tropospheric temperature, implying the existence of a stratospheric 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 stratosphere through the tropical tropopause layer, with the rest coming from increases in water vapor entering through the extratropical tropopause.

  11. Light Absorption in the Stratosphere: Trend, Soot Aerosol Concentration and Contribution by...

    NASA Technical Reports Server (NTRS)

    Pueschel, R. F.; Verma, S.; Strwwa, A. W.; Ferry, G. V.; Hamill, P.; Vay, S.; Gore, Warren J. Y. (Technical Monitor)

    1997-01-01

    The light absorption coefficient, Beta(a) of the stratospheric aerosol is an important quantity that determines its radiative effects. When combined with the aerosol scattering coefficient, Beta(a) it becomes possible to evaluate the aerosol single scatter albedo, omega = Beta(s)/(Beta(s) + Beta(a)) which is essential for modeling the overall radiative effects of the stratospheric aerosol. Pollack1 determined that omega = 0.98 is a critical value that separates stratospheric cooling from warming.

  12. On the connection between stratospheric water vapour changes and widespread severe denitrification in the Arctic

    NASA Astrophysics Data System (ADS)

    Khosrawi, Farahnaz; Urban, Jo; Lossow, Stefan; Stiller, Gabi; Murtagh, Donal

    2013-04-01

    Water vapour is one of the most important greenhouse gases and plays a key role in the chemistry of the upper troposphere and lower stratosphere (UT/LS). Any changes in atmospheric water vapour bring important implications for the global climate. Long-term ground-based and satellite measurements indicate an increase of stratospheric water vapour abundance by an average of 1 ppmv during the last 30 years (1980-2010). Increases in stratospheric water vapour cool the stratosphere but warm the troposphere. Both the cooling of the stratosphere and the increase in water vapour enhance the potential for the formation of polar stratospheric clouds. More than a decade ago it already was suggested that a cooling of stratospheric temperatures by 1 K or an increase of 1 ppmv of stratospheric water vapor could promote denitrification, the permanent removal of nitrogen species from the stratosphere by solid polar stratospheric cloud particles. In fact, during the two recent Arctic winter 2009/2010 and 2010/2011 the strongest denitrification in the recent decade was measured by Odin/SMR. In the latter winter denitrification lead also to severe ozone depletion with similar extensions as the Antarctic "ozone hole". In this study, the correlation between observed water vapour trends and the recent temperature evolution in the Arctic together with trace gas measurements and PSC observations are considered to investigate a possible connection between the increase in stratospheric water vapour and polar stratospheric cloud formation/denitrification.

  13. Contrasting Effects of Central Pacific and Eastern Pacific El Nino on Stratospheric Water Vapor

    NASA Technical Reports Server (NTRS)

    Garfinkel, Chaim I.; Hurwitz, Margaret M.; Oman, Luke D.; Waugh, Darryn W.

    2013-01-01

    Targeted experiments with a comprehensive chemistry-climate model are used to demonstrate that seasonality and the location of the peak warming of sea surface temperatures dictate the response of stratospheric water vapor to El Nino. In spring, El Nino events in which sea surface temperature anomalies peak in the eastern Pacific lead to a warming at the tropopause above the warm pool region, and subsequently to more stratospheric 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 warm pool region are nonuniform and less water vapor enters the stratosphere. The difference in water vapor in the lower stratosphere between the two variants of El Nino approaches 0.3 ppmv, while the difference between the winter and spring responses exceeds 0.5 ppmv.

  14. The stratospheric polar vortex: evolving perspectives

    NASA Astrophysics Data System (ADS)

    Plumb, R. A.

    2005-12-01

    dynamics has included the remote effects on the vortex of the QBO in the tropical stratosphere, and of gravity wave drag and solar cycle influences at higher altitudes. In turn, there is accumulating evidence that variability in the polar vortices has remote effects at lower altitudes, manifested via the "annular mode" signals in the troposphere. Such issues raise questions about the interconnections between the troposphere, stratosphere and mesosphere, and about whether it makes sense, for example, to follow what used to be the conventional view and to regard stratospheric planetary waves and their impacts as being slaved to tropospheric meteorology. Amongst many of lines of evidence, no proximate tropospheric cause has been identified for the unprecedented Antarctic major warming of September 2002.

  15. Trends in stratospheric temperature

    NASA Technical Reports Server (NTRS)

    Schoeberl, M. R.; Newman, P. A.; Rosenfield, J. E.; Angell, J.; Barnett, J.; Boville, B. A.; Chandra, S.; Fels, S.; Fleming, E.; Gelman, M.

    1989-01-01

    Stratospheric temperatures for long-term and recent trends and the determination of whether observed changes in upper stratospheric 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 stratosphere 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 stratospheric ozone changes reported by the Solar Backscatter Ultraviolet (SBUV) instrument aboard Nimbus-7 and the Stratospheric Aerosol and Gas Experiment (SAGE) instruments.

  16. Dynamic characteristics of observed sudden warmings

    NASA Technical Reports Server (NTRS)

    Dartt, D. G.; Venne, D. E.

    1986-01-01

    The planetary wave dynamics of stratospheric sudden warmings in the Northern Hemisphere for a large number of observed events that occurred during winters from 1970 to 1975 and 1978 to 1981 are investigated. The analysis describes wave propagation and zonal flow interaction from the troposphere upwards to near 50 km, and in some years to near 80 km. Three primary topics are covered here: (1) the interaction of zonally propagating and quasi-stationary planetary waves during warming events; (2) planetary wave influence on zonal flow near the stratopause; and (3) planetary wave propagation to near 80 km as seen from Stratospheric and Mesospheric Sounder (SAMS) data.

  17. Triton - Stratospheric molecules and organic sediments

    NASA Technical Reports Server (NTRS)

    Thompson, W. Reid; Singh, Sushil K.; Khare, B. N.; Sagan, Carl

    1989-01-01

    Continuous-flow plasma discharge techniques show production rates of hydrocarbons and nitriles in N2 + CH4 atmospheres appropriate to the stratosphere 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 stratosphere. 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 stratosphere 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 stratosphere is as warm as expected. Both organic haze and condensed gases will provide a substantial UV and visible opacity in Triton's atmosphere.

  18. Stratospheric Impact of Varying Sea Surface Temperatures

    NASA Technical Reports Server (NTRS)

    Newman, Paul A.; Nash, Eric R.; Nielsen, Jon E.; Waugh, Darryn; Pawson, Steven

    2004-01-01

    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 stratosphere in comparison to an NCEP/NCAR reanalysis climatology. In particular, the northern hemisphere has numerous major and minor stratospheric warming, 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 stratosphere and the polar vortex is weaker than is found in the mid-winter southern hemisphere. Mean temperature differences in the lower stratosphere 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.

  19. The tropospheric-stratospheric polar vortex breakdown of January 1977

    NASA Technical Reports Server (NTRS)

    Quiroz, R. S.

    1977-01-01

    An extraordinary warming of the stratosphere in December-January 1976-77 was followed by tropospheric warming in the polar region and cooling in middle latitudes. During January 10-20, the associated polar anticyclone extended from the surface to 10 mb. Antecedents of the polar vortex breakdown are reviewed with the aid of results of zonal-harmonic analyses of planetary waves, for heights of the pressure surfaces (700-10 mb), temperature, and mean stratospheric temperature (the latter determined from satellite radiation measurements). Wave 1 in height and temperature played a dominant role in the stratosphere, attaining amplitudes of 1600 gpm and 25 C, respectively, at 10 mb. On the other hand, superposition of retrogressing wave 1 and quasi-stationary wave 2 in the height of the 300-mb surface, with individual amplitudes exceeding 300 gpm, is judged to have been an important factor in the overall development.

  20. Stratospheric dynamics following the eruption of Mt. Pinatubo

    NASA Astrophysics Data System (ADS)

    Match, Aaron; Abalos, Marta; Sheng, Jianxiong; Stenke, Andrea; Paynter, David; Fueglistaler, Stephan

    2016-04-01

    Large volcanic eruptions at low latitudes such as that of Mt. Pinatubo in June 1991 can lead to massively enhanced stratospheric aerosol loading for up to about two years. The enhanced aerosol loading leads to a global cooling in the troposphere as a result of the larger albedo. In the lower stratosphere, the enhanced aerosol leads to a warming of several Kelvins as a result of enhanced absorbed radiation. It has been argued that the characteristic temperature change from volcanic aerosols in the stratosphere - a warming of the low latitudes relative to the high latitudes - tends to induce a more stable polar vortex, and as such a reduced residual circulation. More recently, however, a number of studies have presented calculations of the residual circulation from meteorological reanalyses that suggest that the residual circulation may have been anomalously strong following the Mt. Pinatubo eruption. Similarly, unexpected ozone anomalies in the Southern Hemisphere stratosphere have been linked to a stronger residual circulation. Here, we will present General Circulation Model results, using models ranging in complexity from a primitive equation model to Chemistry-Climate Models, in combination with reanalysis data that aim to provide a mechanistic understanding of the anomalous stratospheric state following the eruption of Mt. Pinatubo. Of particular interest are the impact on model results of the relatively large differences in heating rate perturbations between different data sets of stratospheric aerosol, and the responses in atmospheric dynamics arising from, on the one hand, the specific sea surface temperature pattern of that period and, on the other hand, the response arising from the stratospheric radiative heating perturbation. Our model results suggest that the adjustment in the stratospheric state in response to the in-situ radiative heating perturbation from the volcanic aerosol is probably insufficient to explain the enhanced residual circulation seen

  1. Stratospheric water vapor feedback

    PubMed Central

    Dessler, A. E.; Schoeberl, M. R.; Wang, T.; Davis, S. M.; Rosenlof, K. H.

    2013-01-01

    We show here that stratospheric water vapor variations play an important role in the evolution of our climate. This comes from analysis of observations showing that stratospheric water vapor increases with tropospheric temperature, implying the existence of a stratospheric 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 stratosphere through the tropical tropopause layer, with the rest coming from increases in water vapor entering through the extratropical tropopause. PMID:24082126

  2. Stratospheric H2O

    NASA Technical Reports Server (NTRS)

    Ellsaesser, H. W.; Harries, J. E.; Kley, D.; Penndorf, R.

    1980-01-01

    The present state of our knowledge and understanding of H2O in the stratosphere is reviewed. This reveals continuing discrepancies between observations and expectations following from the Brewer-Dobson hypothesis of stratospheric circulation. In particular, available observations indicate unexplained upward and poleward directed H2O gradients immediately downstream from the tropical tropopause and variable vertical gradients above 20 km which generally disagree with those expected from oxidation of CH4.

  3. Stratospheric ozone is decreasing

    NASA Astrophysics Data System (ADS)

    Kerr, Richard A.

    1988-03-01

    The recent discovery that chlorofluorocarbons create the Antarctic ozone hole every October through reactions mediated by ice particles formed at the lowest temperatures of the stratosphere is discussed. A large-scale reanalysis of measurements reveals that protective stratospheric ozone has decreased during the past 17 yrs with some decreases greatly exceeding predictions. It is noted that standard models did not, and still do not, include the ice in their reaction schemes. A tendency toward larger losses at higher colder latitudes is seen.

  4. Influence of Stratospheric Ozone Distribution on Tropospheric Circulation Patterns

    NASA Astrophysics Data System (ADS)

    Barodka, Siarhei; Krasouski, Aliaksandr; Mitskevich, Yaroslav; Shalamyansky, Arkady

    2015-04-01

    In the present study we investigate the cause-and-effect relationship between the stratospheric ozone distribution and tropospheric circulation, focusing our attention mainly on the possible "top-down" side of this interaction: the impact of the stratosphere 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 stratospheric ozone distribution, temperature field of the lower stratosphere 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 stratospheric 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 stratospheric 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 stratospheric 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 stratospheric warming (SSW) events. In particular, the November 2013 SSW over Eastern Siberia, which is characterized by abrupt stratospheric temperatures change in the course of one day

  5. Carbonyl sulfide: No remedy for global warming

    NASA Astrophysics Data System (ADS)

    Taubman, Steven J.; Kasting, James F.

    1995-04-01

    The enhancement of the stratospheric aerosol layer caused by the eruption of Mt. Pinatubo (June 15, 1991), and the subsequent cooling of the earth's lower atmosphere [Dutton and Christy, 1992; Minnis et al., 1993] shows that stratospheric aerosols can have a strong effect on the earth's climate. This supports the notion that the intentional enhancement of the stratospheric aerosol layer through increased carbonyl sulfide (OCS) emissions might be an effective means for counteracting global warming. Through the use of a one-dimensional photochemical model, we investigate what effect such a program might have on global average stratospheric ozone. In addition, we consider the impact of enhanced OCS emissions on rainwater acidity and on the overall health of both plants and animals. We find that while the warming produced by a single CO2 doubling (1 to 4°C) might be offset with ozone losses of less than 5%, any attempt to use carbonyl sulfide as a permanent solution to global warming could result in depletion of global average ozone by 30% or more. We estimate that in order to achieve cooling of 4°C rainwater pH would fall to between 3.5 and 3.8. Finally, a 4°C cooling at the surface will require that ambient near ground OCS levels rise to above 10 ppmv which is probably greater than the safe exposure limit for humans. Thus, enhanced OCS emissions do not provide an environmentally acceptable solution to the problem of global warming.

  6. Global Warming.

    ERIC Educational Resources Information Center

    Hileman, Bette

    1989-01-01

    States the foundations of the theory of global warming. Describes methodologies used to measure the changes in the atmosphere. Discusses steps currently being taken in the United States and the world to slow the warming trend. Recognizes many sources for the warming and the possible effects on the earth. (MVL)

  7. Disentangling the Roles of Various Forcing Mechanisms on Stratospheric Temperature Changes Since 1979 with the NASA GEOSCCM

    NASA Technical Reports Server (NTRS)

    Aquila, Valentina; Swartz, W.; Colarco, P.; Pawson, S.; Polvani, L.; Stolarski, R.; Waugh, D.

    2015-01-01

    Observations show that the cooling of global stratospheric 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 stratospheric 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 stratospheric temperatures, where the decrease in ozone depleting substances due to the Montreal Protocol slowed ozone depletion and therefore also the cooling of the stratosphere. Volcanic eruptions also caused a significant warming of the stratosphere after 1995. The observed general cooling is mainly caused by increasing ozone depleting substances in the lower stratosphere, and greenhouse gases in the middle and upper stratosphere.

  8. Seasonal variation of radiance variances from satellite observations Implication of seasonal variation of available potential energy in the stratosphere

    NASA Technical Reports Server (NTRS)

    Chen, T.-C.; Stanford, J. L.

    1980-01-01

    Nimbus 5 satellite radiances for the period 1973-74 are used to examine the seasonal variation of available potential energy in the stratosphere in order to provide a further observational basis for a long-term numerical simulation of stratospheric circulation. The maximum value of stratospheric zonal available potential energy, A(Z), in the upper and middle stratosphere shows pronounced variations between winter and summer, while little variation occurs in the lower stratospheric A(Z). The aperiodic occurrence of sudden warmings complicates the seasonal variation of A(Z) and A(E) (eddy available potential energy) in the stratosphere, making the energetics irregular. Time-Fourier analysis reveals that the primary variation of A(Z) and A(E) in the stratosphere is annual and semiannual, respectively.

  9. Stratospheric Airship Design Sensitivity

    NASA Astrophysics Data System (ADS)

    Smith, Ira Steve; Fortenberry, Michael; Noll, . James; Perry, William

    2012-07-01

    The concept of a stratospheric or high altitude powered platform has been around almost as long as stratospheric 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 stratospheric 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 stratosphere 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 stratospheric 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.

  10. Ozone and the stratosphere

    NASA Technical Reports Server (NTRS)

    Shimazaki, Tatsuo

    1987-01-01

    It is shown that the stratospheric 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 stratosphere, 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 stratospheric ozone layer and thus have a profound impact on the world climate and on life.

  11. Analysis of the Interactions of Planetary Waves with the Mean Flow of the Stratosphere

    NASA Technical Reports Server (NTRS)

    Newman, Paul A.

    2007-01-01

    During the winter period, large scale waves (planetary waves) are observed to propagate from the troposphere into the stratosphere. Such wave events have been recognized since the 1 950s. The very largest wave events result in major stratospheric warmings. These large scale wave events have typical durations of a few days to 2 weeks. The wave events deposit easterly momentum in the stratosphere, decelerating the polar night jet and warming 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 warmings. We will illustrate some of the differences between major and minor warming wave events. We will further illustrate the feedback by the mean flow on subsequent wave events.

  12. Human Health Effects of Ozone Depletion From Stratospheric Aircraft

    NASA Technical Reports Server (NTRS)

    Wey, Chowen (Technical Monitor)

    2001-01-01

    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 stratospheric ozone impacts of a hypothetical HSCT fleet, although recent research indicates that a fleet of HSCT is predicted to contribute to climate warming as well. This report also briefly describes the international and domestic institutional frameworks established to address stratospheric ozone depletion, as well as those established to control pollution from aircraft engine exhaust emissions.

  13. Stratospheric dynamics and midlatitude jets under geoengineering with space mirrors and sulfate and titania aerosols

    NASA Astrophysics Data System (ADS)

    Ferraro, A. J.; Charlton-Perez, A. J.; Highwood, E. J.

    2015-01-01

    The impact on the dynamics of the stratosphere of three approaches to geoengineering by solar radiation management is investigated using idealized simulations of a global climate model. The approaches are geoengineering with sulfate aerosols, titania aerosols, and reduction in total solar irradiance (representing mirrors placed in space). If it were possible to use stratospheric aerosols to counterbalance the surface warming produced by a quadrupling of atmospheric carbon dioxide concentrations, tropical lower stratospheric radiative heating would drive a thermal wind response which would intensify the stratospheric polar vortices. In the Northern Hemisphere this intensification results in strong dynamical cooling of the polar stratosphere. Northern Hemisphere stratospheric sudden warming events become rare (one and two in 65 years for sulfate and titania, respectively). The intensification of the polar vortices results in a poleward shift of the tropospheric midlatitude jets in winter. The aerosol radiative heating enhances the tropical upwelling in the lower stratosphere, influencing the strength of the Brewer-Dobson circulation. In contrast, solar dimming does not produce heating of the tropical lower stratosphere, and so there is little intensification of the polar vortex and no enhanced tropical upwelling. The dynamical response to titania aerosol is qualitatively similar to the response to sulfate.

  14. Stratospheric Aerosol Measurements

    NASA Technical Reports Server (NTRS)

    Pueschel, Rudolf, F.; Gore, Warren J. (Technical Monitor)

    1998-01-01

    Stratospheric aerosols affect the atmospheric energy balance by scattering and absorbing solar and terrestrial radiation. They also can alter stratospheric chemical cycles by catalyzing heterogeneous reactions which markedly perturb odd nitrogen, chlorine and ozone levels. Aerosol measurements by satellites began in NASA in 1975 with the Stratospheric Aerosol Measurement (SAM) program, to be followed by the Stratospheric Aerosol and Gas Experiment (SAGE) starting in 1979. Both programs employ the solar occultation, or Earth limb extinction, techniques. Major results of these activities include the discovery of polar stratospheric clouds (PSCs) in both hemispheres in winter, illustrations of the impacts of major (El Chichon 1982 and Pinatubo 1991) eruptions, and detection of a negative global trend in lower stratospheric/upper tropospheric aerosol extinction. This latter result can be considered a triumph of successful worldwide sulfur emission controls. The SAGE record will be continued and improved by SAGE III, currently scheduled for multiple launches beginning in 2000 as part of the Earth Observing System (EOS). The satellite program has been supplemented by in situ measurements aboard the ER-2 (20 km ceiling) since 1974, and from the DC-8 (13 km ceiling) aircraft beginning in 1989. Collection by wire impactors and subsequent electron microscopic and X-ray energy-dispersive analyses, and optical particle spectrometry have been the principle techniques. Major findings are: (1) The stratospheric background aerosol consists of dilute sulfuric acid droplets of around 0.1 micrometer modal diameter at concentration of tens to hundreds of monograms per cubic meter; (2) Soot from aircraft amounts to a fraction of one percent of the background total aerosol; (3) Volcanic eruptions perturb the sulfuric acid, but not the soot, aerosol abundance by several orders of magnitude; (4) PSCs contain nitric acid at temperatures below 195K, supporting chemical hypotheses

  15. Measurements of stratospheric bromine

    NASA Technical Reports Server (NTRS)

    Sedlacek, W. A.; Lazrus, A. L.; Gandrud, B. W.

    1984-01-01

    From 1974 to 1977, molecules containing acidic bromine were sampled in the stratosphere 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 stratosphere. Seasonal variability seems to be small.

  16. Chlorofluoromethanes and the Stratosphere

    NASA Technical Reports Server (NTRS)

    Hudson, R. D. (Editor)

    1977-01-01

    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 stratospheric 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.

  17. A consistent definition of the Arctic polar vortex breakup in both the lower and upper stratosphere

    NASA Astrophysics Data System (ADS)

    Choi, W.; Seo, J.

    2014-12-01

    Breakup of the polar vortex is a dominant feature of the seasonal transition from winter to summer in the stratosphere, which significantly affects stratospheric O3 concentration and tropospheric weather. Previously several criteria for the vortex breakup have been suggested based on the potential vorticity (PV) and wind speed, however, those mainly have focused on the lower stratospheric vortex of which spatiotemporal evolution and decay are more continuous than those of the upper stratospheric vortex. To find a consistent criterion for the vortex breakup in both the lower and upper stratosphere, the present study defined a polar vortex breakup day as when PV gradient at the polar vortex edge becomes lower than that at the subtropical edge on the area equivalent latitude based on PV. With applying the new definition to the UK Met Office reanalysis data, the breakup days of the Arctic polar vortices on 18 isentropic levels from 450 K to 1300 K were calculated for the period of 1993-2005. In comparison with CH4, N2O and O3 measured by the ILAS and POAM II/III satellite instruments, the breakup days are well consistent with changes in the distribution of such tracers as well as their zonal standard deviations associated with the vortex structure breaking and irreversible mixing. The vortex breakup in the upper stratosphere occurs more or less a month prior to that in the middle and lower stratosphere while the stratospheric final warming events occurs simultaneously in the upper and lower stratosphere.

  18. Northern Winter Climate Change: Assessment of Uncertainty in CMIP5 Projections Related to Stratosphere-Troposphere Coupling

    NASA Technical Reports Server (NTRS)

    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.

    2014-01-01

    Future changes in the stratospheric 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-stratosphere circulation. Here we assess northern winter stratospheric change and its potential to influence surface climate change in the Coupled Model Intercomparison Project-Phase 5 (CMIP5) multimodel ensemble. In the stratosphere 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 stratospheric easterly change is common feature in future climate projections. This stratospheric wind change, however, shows a significant spread among the models. By using linear regression, we quantify the impact of tropical upper troposphere warming, polar amplification, and the stratospheric wind change on SLP. We find that the intermodel spread in stratospheric wind change contributes substantially to the intermodel spread in Arctic SLP change. The role of the stratosphere in determining part of the spread in SLP change is supported by the fact that the SLP change lags the stratospheric zonally averaged wind change. Taken together, these findings provide further support for the importance of simulating the coupling between the stratosphere and the troposphere, to narrow the uncertainty in the future projection of tropospheric circulation changes.

  19. Sensitivity of Stratospheric Dynamics to Uncertainty in O3 Production

    NASA Astrophysics Data System (ADS)

    Hsu, J. C.; Prather, M. J.; Bergmann, D. J.; Cameron-Smith, P. J.

    2013-12-01

    Some key photochemical uncertainties that cannot be readily eliminated by current observations translate into a range of stratospheric O3 abundances in the tens of percent. The uncertainty in O3 production due to that in the cross sections for O2 in the Hertzberg continuum is studied here with the NCAR Community Atmosphere Model, which allows for interactive climate and ozone chemistry. A min-max range in the O2 cross sections of 30%, consistent with current uncertainties, changes O3 abundances in the lower tropical stratosphere by up to 30%, with a relatively smaller and opposite change above 30 hPa. Here we have systematically examined the changes in the time-mean state, the seasonal cycle, and the interannual variability of the temperature and circulation associated with the +/-30% change in O2 cross sections. This study points to the important role of O3 in the lower tropical stratosphere in determining the physical characteristics of the tropical tropopause layer. Reducing O2 cross sections by 30% increases ozone abundances which warms the lower stratosphere (60S -60N; 2K maximum at equator) and lowers the tropopause height by 100-200m (30S -30N). The large-scale warming leads to enhanced stratification near the tropopause which reduces upward wave propagation everywhere except for high latitudes. The lowermost tropical stratosphere is better ventilated during austral winter. The annual cycle of ozone is amplified. The interannual variability of the winter stratospheric polar vortices also increases, but the mechanism involves wave-mean flow interaction and the exact role of ozone in it needs further investigation.

  20. Mesosphere-Stratosphere Coupling: Implications for Climate Variability and Trends

    NASA Technical Reports Server (NTRS)

    Baldwin, Mark P.

    2004-01-01

    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 stratosphere to the troposphere. The observational link for stratospheric sudden warmings 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 stratosphere 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 warming 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 stratosphere evolve through the winter and affect the polar vortex.

  1. In-situ Observations of Mid-latitude Forest Fire Plumes Deep in the Stratosphere

    NASA Technical Reports Server (NTRS)

    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

    2004-01-01

    We observed a plume of air highly enriched in carbon monoxide and particles in the stratosphere 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 stratosphere, which is not fully captured by large-scale atmospheric transport models. This process indicates that the stratospheric ozone layer could be sensitive to changes in forest burning associated with climatic warming.

  2. Sensitivity of Stratospheric Geoengineering with Black Carbon to Aerosol Size and Altitude of Injection

    NASA Technical Reports Server (NTRS)

    Kravitz, Ben; Robock, Alan; Shindell, Drew T.; Miller, Mark A.

    2012-01-01

    Simulations of stratospheric 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 stratosphere would cause little surface cooling for large radii but a large amount of surface cooling for small radii and stratospheric warming of over 60 C. With the exception of small particles, increasing the altitude of injection increases surface cooling and stratospheric warming. Stratospheric warming causes global ozone loss by up to 50% in the small radius case. The Antarctic shows less ozone loss due to reduction of polar stratospheric 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.

  3. Ensemble climate simulations using a fully coupled ocean-troposphere-stratosphere general circulation model.

    PubMed

    Huebener, H; Cubasch, U; Langematz, U; Spangehl, T; Niehörster, F; Fast, I; Kunze, M

    2007-08-15

    Long-term transient simulations are carried out in an initial condition ensemble mode using a global coupled climate model which includes comprehensive ocean and stratosphere components. This model, which is run for the years 1860-2100, allows the investigation of the troposphere-stratosphere 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, stratosphere and ocean. The enhanced stratospheric resolution leads to the simulation of sudden stratospheric warmings; 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 stratosphere compared with present-day simulations, and to the doubling of the number of stratospheric warmings. 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.

  4. Generation of waves by jet-stream instabilities in winter polar stratosphere/mesosphere

    NASA Astrophysics Data System (ADS)

    Shpynev, B. G.; Churilov, S. M.; Chernigovskaya, M. A.

    2015-12-01

    In the paper we investigate the manifestation of large-scale and middle-scale atmospheric irregularities observed on stratosphere/mesosphere heights. We consider typical patterns of circulation in stratosphere 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 stratosphere/lower mesosphere and reasons for creation of flaky structure of polar stratosphere. Also we analyze conditions that are favorable for splitting of winter circumpolar vortex during sudden stratosphere warming events and role of phase difference tides in this process. The analysis of vertical structure of the stratosphere 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 stratosphere warming 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.

  5. Antarctic stratospheric ice crystals

    NASA Technical Reports Server (NTRS)

    Goodman, J.; Toon, O. B.; Pueschel, R. F.; Snetsinger, K. G.; Verma, S.

    1989-01-01

    Ice crystals were replicated over the Palmer Peninsula at approximately 72 deg S on six occasions during the 1987 Airboirne 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 stratospheric dehydration processes through sedimentation. Evidence of scavenging of submicron particles further suggests that the ice crystals may be effective in the removal of stratospheric chemicals.

  6. Long-term variability of stratospheric temperature above central Antarctica

    NASA Astrophysics Data System (ADS)

    Makarova, L. N.; Shirochkov, A. V.

    Long-term variations of atmospheric temperature at different isobaric surfaces above central Antarctica were studied. Data of atmospheric balloon soundings at two Antarctic intercontinental stations Vostok and Amundsen-Scott (South Pole) taken for the last 40 years were used in this study. It was found that stratospheric temperature at both stations averaged seasonally or annually does not demonstrate any meaningful correlation with correspondent sunspot number variations. On the other hand, there is a notable correlation between stratospheric temperature at both stations and annually averaged values of the solar wind dynamic pressure. Mutual coupling between stratosphere thermal regimes at two stations demonstrates obvious seasonal dependence: there is a good correlation between them in summer while it disappears in winter and equinoxes. It was found also that stratospheric temperature above South Pole Station varies in the same manner as correspondent parameter above North Pole as reported previously by Labitzke and Naujokat [SPARC Newsletter 15 (2000) 11]. At both geographic poles, stratospheric temperature had obvious tendency to warming in 1972-1995. On the other hand, the correspondent Vostok data demonstrates clear tendency to cooling in this period. Possible explanations of these results are given.

  7. Oxygen Compounds in Saturn's Stratosphere During the 2010 Northern Storm

    NASA Astrophysics Data System (ADS)

    Bjoraker, G. L.; Hesman, B. E.; Achterberg, R. K.; Jennings, D. E.; Romani, P. N.; Fletcher, L. N.; Irwin, P.

    2013-12-01

    The massive storm at 40N on Saturn that began in December 2010 has produced significant and long-lived changes in temperature and species abundances in the stratosphere throughout the northern hemisphere (Hesman et al. 2012a, Fletcher et al. 2012). The northern storm region has been observed on many occasions between January 2011 and January 2013 by Cassini's Composite Infrared Spectrometer (CIRS). In this time period, temperatures in regions referred to as 'beacons' (warm regions in the stratosphere at certain longitudes in the storm latitude) became significantly warmer than pre-storm values of 140K, peaking at 220K in May 2011 followed by gradual cooling. Hydrocarbon emission greatly increased over pre-storm values and then slowly decayed as the beacon cooled. Radiative transfer modeling has revealed that this increased emission is due to enhanced gas abundances for many of these species, rather than simply due to the temperature changes alone (Hesman et al. 2012b, Bjoraker et al 2012). In order to build a comprehensive picture of the changes to the stratosphere due to the 2010 northern storm we are now investigating the oxygen compounds in Saturn's stratosphere to determine if similar changes in these species were measured. The time evolution of stratospheric CO2 and H2O abundances in the beacon regions throughout 2011 and 2012 will be presented and compared with pre-storm measurements made in 2010.

  8. Impact of geoengineered aerosols on the troposphere and stratosphere

    SciTech Connect

    Tilmes, S.; Garcia, Rolando R.; Kinnison, Douglas E.; Gettelman, A.; Rasch, Philip J.

    2009-06-27

    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 stratospheric chemistry, including heterogeneous chemistry in the polar regions, is considered in this simulation. In the geoengineering simulation, a constant stratospheric 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 warming 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 stratospheric processes for estimating the impact of stratospheric aerosols on the Earth’s climate. Changes in stratospheric 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.

  9. Science in the Stratosphere

    NASA Technical Reports Server (NTRS)

    Lester, Dan

    1997-01-01

    The Science in the Stratosphere 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 Stratosphere 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 Stratosphere 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.

  10. Stratospheric Aerosols for Solar Radiation Management

    NASA Astrophysics Data System (ADS)

    Kravitz, Ben

    SRM in the context of this entry involves placing a large amount of aerosols in the stratosphere to reduce the amount of solar radiation reaching the surface, thereby cooling the surface and counteracting some of the warming 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 warming from greenhouse gases is due to longwave (thermal) emission, compensating for this warming 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 stratosphere. 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

  11. Freezing Behavior of Stratospheric Sulfate Aerosols Inferred from Trajectory Studies

    NASA Technical Reports Server (NTRS)

    Tabazadeh, A.; Toon, O. B.; Hamill, Patrick

    1995-01-01

    Based on the trajectory analysis presented in this paper, a new mechanism is described for the freezing of the stratospheric 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 warming 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 warming. Of all the ER-2 flights described, only the polar stratospheric 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 stratospheric H2SO4 aerosols may undergo a phase transition to SAT upon warming at approximately 198 K after going through a cooling cycle to about 194 K or lower.

  12. 'The plunger hypothesis' - predicting the tropospheric impact of extreme stratospheric events

    NASA Astrophysics Data System (ADS)

    Clark, Simon; Baldwin, Mark; Stephenson, David

    2016-04-01

    The coupling of events in the polar stratosphere to those in the polar troposphere is not currently understood. Extreme events in the stratosphere have been identified to have a lasting influence on the tropospheric circulation below for a period of up to 60 days. As such understanding the downward propagation of stratospheric circulation anomalies would be beneficial to surface forecasting. In this work we use the new 'plunger hypothesis', that mass fluxes into and out of the polar region compress the polar column of air - in a manner similar to a plunger - and cause pressure and temperature anomalies. We demonstrate how a quasigeostrophic assumption within this hypothesis allows for the prediction of mass fluxes across the boundary to the polar region given the pressure distribution at the boundary. This then allows for a prediction of how a given stratospheric event such as a sudden stratospheric warming (SSW) or a strong vortex event influences the polar troposphere. The performance of this hypothesis is tested; its usefulness in improving surface forecasts, its accuracy in response to stratospheric events, and its ability to predict downward propagation of Arctic Oscillation (AO) index in the aftermath of extreme stratospheric events. The link between this work and the PV inversion formulation of stratosphere-troposphere coupling is discussed. This work forms part of a three and a half year PhD project.

  13. Saturn's Stratospheric Oxygen Compounds

    NASA Astrophysics Data System (ADS)

    Romani, Paul N.; Delgado Díaz, Héctor E.; Bjoraker, Gordon; Hesman, Brigette; Achterberg, Richard

    2016-10-01

    There are three known oxygenated species present in Saturn's upper atmosphere: H2O, CO and CO2. The ultimate source of the water must be external to Saturn as Saturn's cold tropopause effectively prevents any internal water from reaching the upper atmosphere. The carbon monoxide and dioxide source(s) could be internal, external, produced by the photochemical interaction of water with Saturn's stratospheric hydrocarbons or some combination of all of these. At this point it is not clear what the external source(s) are.Cassini's Composite InfraRed Spectrometer (CIRS) has detected emission lines of H2O and CO2 (Hesman et al., DPS 2015, 311.16 & Abbas et al. 2013, Ap. J. doi:10.1088/0004-637X/776/2/73) on Saturn. CIRS also retrieves the temperature of the stratosphere using CH4 lines at 7.7 microns. Using CIRS retrieved temperatures, the mole fraction of H2O at the 0.5-5 mbar level can be retrieved and the CO2 mole fraction at ~1-10 mbar. Coupled with ground based observations of CO (Cavalié et al., 2010, A&A, DOI: 10.1051/0004-6361/200912909) these observations provide a complete oxygen compound data set to test photochemical models.Preliminary results will be presented with an emphasis on upper limit analysis to determine the percentage of stratospheric CO and CO2 that can be produced photochemically from CIRS observational constraints on the H2O profile.

  14. The stratosphere: Present and future

    NASA Technical Reports Server (NTRS)

    Hudson, R. D. (Editor); Reed, E. I. (Editor)

    1979-01-01

    The present status of stratospheric science is discussed. The three basic elements of stratospheric 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.

  15. Jupiter Stratospheric Haze Comparison

    NASA Technical Reports Server (NTRS)

    1996-01-01

    These two views of Jupiter obtained by the imaging system aboard the Galileo spacecraft show evidence of strikingly different stratospheric hazes between the polar regions and low or mid latitudes. The Great Red Spot shows in one mosaic, centered at about 20 degrees South latitude and taken on June 26, 1996 at a range of 1.46 million kilometers. The other mosaic is centered near 50 degrees North latitude, and was taken on November 4, 1996 at a range of 1.60 million kilometers.

    North is at the top in both images. In the Red Spot image, the edge of the planet (limb) runs in a single arc from lower left to upper right, with dark space at lower right. In the polar image, the limb runs in two segments across the top right corner, with dark space at top right. Both images are mosaics; the offset of the individual frames of the mosaic produces the jagged border and the break in the polar limb.

    These are false color images, constructed specifically to reveal cloud elevation differences. Three color channels are used. The red channel is an image taken at a near infrared wavelength where methane in Jupiter's atmosphere is strongly absorbing, and therefore gives no information about deep clouds but reveals high clouds. The green channel is a weaker methane band, and the blue channel is assigned to a wavelength where Jupiter's atmosphere is transparent. Thus red features indicate high hazes. A view near the edge of the planet accentuates the high hazes because of the slanting path of the line of sight.

    The pronounced reddening near the edge of the planet in polar regions indicates a high stratospheric haze. Comparison with the Great Red Spot shows that such a high haze is absent at that latitude. Detailed analysis shows that a stratospheric haze exists at both latitudes but is approximately 50 km higher near the poles. It is likely that the high polar haze is produced by magnetospheric particles, which travel along magnetic field lines and bombard the upper atmosphere

  16. Winter warming from large volcanic eruptions

    SciTech Connect

    Robock, A.; Mao, J.

    1992-01-01

    An examination of the Northern Hemisphere winter surface temperature patterns after the 12 largest volcanic eruptions from 1883-1992 shows warming 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 stratosphere by the volcanic aerosols is responsible for the regions of warming, while the cooling is caused by blocking of incoming sunlight.

  17. Winter warming from large volcanic eruptions

    NASA Technical Reports Server (NTRS)

    Robock, Alan; Mao, Jianping

    1992-01-01

    An examination of the Northern Hemisphere winter surface temperature patterns after the 12 largest volcanic eruptions from 1883-1992 shows warming 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 stratosphere by the volcanic aerosols is responsible for the regions of warming, while the cooling is caused by blocking of incoming sunlight.

  18. Stratospheric aerosols and climatic change

    NASA Technical Reports Server (NTRS)

    Baldwin, B.; Pollack, J. B.; Summers, A.; Toon, O. B.; Sagan, C.; Van Camp, W.

    1976-01-01

    Generated primarily by volcanic explosions, a layer of submicron silicate particles and particles made of concentrated sulfuric acids solution is present in the stratosphere. Flights through the stratosphere may be a future source of stratospheric 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 stratospheric 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 stratospheric 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.

  19. Tropospheric temperature response to stratospheric ozone recovery in the 21st century

    NASA Astrophysics Data System (ADS)

    Hu, Y.; Xia, Y.; Fu, Q.

    2011-08-01

    Recent simulations predicted that the stratospheric 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 stratospheric and tropospheric-surface energy balance, the recovery of stratospheric 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 warmed more than that without considering ozone recovery, suggesting an enhancement of tropospheric warming due to ozone recovery. It is found that the enhanced tropospheric warming 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 warming occurs in the extratropics and polar regions in summer and autumn in both hemispheres, while the enhanced warming is stronger in the Northern Hemisphere than in the Southern Hemisphere. Enhanced warming is also found at the surface. The global and annual mean enhancement of surface warming is about 0.16 K for 2001-2050, with maximum enhancement in the winter Arctic.

  20. On the motion of air through the stratospheric polar vortex

    NASA Technical Reports Server (NTRS)

    Manney, G. L.; Zurek, R. W.; O'Neill, A.; Swinbank, R.

    1994-01-01

    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 stratospheric 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 stratosphere moves poleward and descends into the middle stratosphere. In the SH lower to middle stratosphere, 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 stratosphere 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 warming. 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 stratosphere, 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.

  1. On the Motion of Air through the Stratospheric Polar Vortex.

    NASA Astrophysics Data System (ADS)

    Manney, G. L.; Zurek, R. W.; O'Neill, A.; Swinbank, R.

    1994-10-01

    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 stratospheric polar vortex for Northern Hemisphere (NH) and Southern Hemisphere (SH) winters since the launch of the Upper Atmosphere Research Satellite. Throughout the winter, air from the upper stratosphere moves poleward and descends into the middle stratosphere. In the SH lower to middle stratosphere, 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 stratosphere 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 warming. 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 the SH. In the lower stratosphere, 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.

  2. ORISON, a stratospheric project

    NASA Astrophysics Data System (ADS)

    Ortiz Moreno, Jose Luis; Mueller, Thomas; Duffard, Rene; Juan Lopez-Moreno, Jose; Wolf, Jürgen; Schindler, Karsten; Graf, Friederike

    2016-07-01

    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 stratospheric 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 stratospheric 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.

  3. Increased polar stratospheric ozone losses and delayed eventual recovery owing to increasing greenhouse-gas concentrations

    NASA Astrophysics Data System (ADS)

    Shindell, Drew T.; Rind, David; Lonergan, Patrick

    1998-04-01

    The chemical reactions responsible for stratospheric ozone depletion are extremely sensitive to temperature. Greenhouse gases warm the Earth's surface but cool the stratosphere radiatively and therefore affect ozone depletion. Here we investigate the interplay between projected future emissions of greenhouse gases and levels of ozone-depleting halogen species using a global climate model that incorporates simplified ozone-depletion chemistry. Temperature and wind changes induced by the increasing greenhouse-gas concentrations alter planetary-wave propagation in our model, reducing the frequency of sudden stratospheric warmings in the Northern Hemisphere. This results in a more stable Arctic polar vortex, with significantly colder temperatures in the lower stratosphere and concomitantly increased ozone depletion. Increased concentrations of greenhouse gases might therefore be at least partly responsible for the very large Arctic ozone losses observed in recent winters. Arctic losses reach a maximum in the decade 2010 to 2019 in our model, roughly a decade after the maximum in stratospheric chlorine abundance. The mean losses are about the same as those over the Antarctic during the early 1990s, with geographically localized losses of up to two-thirds of the Arctic ozone column in the worst years. The severity and the duration of the Antarctic ozone hole are also predicted to increase because of greenhouse-gas-induced stratospheric cooling over the coming decades.

  4. AO/NAO Response to Climate Change. 1; Respective Influences of Stratospheric and Tropospheric Climate Changes

    NASA Technical Reports Server (NTRS)

    Rind, D.; Perlwitz, J.; Lonergan, P.

    2005-01-01

    We utilize the GISS Global Climate Middle Atmosphere Model and 8 different climate change experiments, many of them focused on stratospheric climate forcings, to assess the relative influence of tropospheric and stratospheric 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 warming (cooling) experiments and stratospheric cooling (warming) experiments produce more positive (negative) AO/NAO indices. For the typical magnitudes of tropospheric and stratospheric climate changes, the tropospheric response dominates; results are strongest when the tropospheric and stratospheric 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. Stratospheric 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.

  5. Global features of the semiannual oscillation in stratospheric temperatures and comparison between seasons and hemispheres

    NASA Technical Reports Server (NTRS)

    Gao, Xin-Hai; Yu, Wen-Bi; Stanford, John L.

    1987-01-01

    Four years of satellite-derived microwave and infrared radiances are analyzed for the three-dimensional and seasonal variation of semiannual oscillations (SAO) in stratospheric temperatures, with particular focus on high latitudes, to investigate the effect of stratospheric warmings on SAO. Separate analyses of individual seasons in each hemisphere reveal that the strongest SAO in temperature occur in the Northern Hemisphere (NH) winter polar upper stratosphere. These results, together with the latitudinal structure of the temperature SAO and the fact that the NH polar SAO is nearly out of phase with the lower latitude SAO, are consistent with the existence of a global-scale, meridional circulation on the SAO time scale. The results suggest that polar stratospheric warmings are an important source of SAO in both high and low latitude stratospheric temperature fields. Interannual variations, three-dimensional phase structure, and zonal asymmetry of SAO are also detailed. The SH stratospheric SAO is dominated by a localized feature in the high-latitude, eastern hemisphere which tilts westward with height.

  6. Sudden stratospheric warmings seen in MINOS deep underground muon data

    SciTech Connect

    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.

    2009-01-01

    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.

  7. Global Warming?

    ERIC Educational Resources Information Center

    Eichman, Julia Christensen; Brown, Jeff A.

    1994-01-01

    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 warming. (PR)

  8. Troposphere-stratosphere response to large-scale North Atlantic Ocean variability in an atmosphere/ocean coupled model

    NASA Astrophysics Data System (ADS)

    Omrani, N.-E.; Bader, Jürgen; Keenlyside, N. S.; Manzini, Elisa

    2016-03-01

    The instrumental records indicate that the basin-wide wintertime North Atlantic warm 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 stratosphere 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 warm North Atlantic conditions are associated with a stratospheric 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 stratospheric and tropospheric changes are forced by the warm North Atlantic conditions. The basin-wide warming excites a wave-induced stratospheric vortex weakening, stratosphere/troposphere coupling and a high-latitude tropospheric warming. The induced high-latitude tropospheric warming 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 stratosphere. 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 stratosphere/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.

  9. Response of the Antarctic Stratosphere to Two Types of El Nino Events

    NASA Technical Reports Server (NTRS)

    Hurwitz, M. M.; Newman, P. A.; Oman, L. D.; Molod, A. M.

    2010-01-01

    This study is the first to identify a robust El Nino/Southern Oscillation (ENSO) signal in the Antarctic stratosphere. El Nino events are classified as either conventional "cold tongue" events (positive SST anomalies in the Nino 3 region) or "warm 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 stratosphere responds differently to these two types of El Nino events. Consistent with previous studies, "cold tongue" events do not impact temperatures in the Antarctic stratosphere. During "warm 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 stratospheric 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 stratospheric response to "warm pool" El Nino events: the strongest planetary wave driving events are coincident with the easterly phase of the QBO.

  10. Effect of Recent Sea Surface Temperature Trends on the Arctic Stratospheric Vortex

    NASA Technical Reports Server (NTRS)

    Garfinkel, Chaim I.; Oman, Luke; Hurwitz, Margaret

    2015-01-01

    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 stratosphere 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 warming of Indian Ocean, North Pacific, and North Atlantic SSTs, and cooling of the tropical Pacific, have strongly contributed to recent polar stratospheric cooling in late winter and early spring, and to a weak polar stratospheric warming 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 stratospheric 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 stratospheric sudden warmings.

  11. Effects of Stratospheric Sulfate Geoengineering on Food Supply in China

    NASA Astrophysics Data System (ADS)

    Xia, L.; Robock, A.

    2010-12-01

    Possible food supply change is one of the most important concerns in the discussion of stratospheric geoengineering. In regions with high population density, climate changes such as precipitation reduction spurred by stratospheric 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 stratospheric 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 stratospheric 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 warming scenario (A1B) and A1B combined with stratospheric 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 warming only, the geoengineering runs produced summer precipitation reductions in northeastern China but precipitation increases in the Yangtze River region. Without changes

  12. On the Lack of Stratospheric Dynamical Variability in Low-top Versions of the CMIP5 Models

    NASA Technical Reports Server (NTRS)

    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

    2013-01-01

    We describe the main differences in simulations of stratospheric climate and variability by models within the fifth Coupled Model Intercomparison Project (CMIP5) that have a model top above the stratopause and relatively fine stratospheric vertical resolution (high-top), and those that have a model top below the stratopause (low-top). Although the simulation of mean stratospheric climate by the two model ensembles is similar, the low-top model ensemble has very weak stratospheric variability on daily and interannual time scales. The frequency of major sudden stratospheric warming 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 stratospheric variability in the low-top models affects their stratosphere-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 stratospheric variability, however, does not appear to have any impact on the ability of the low-top models to reproduce past stratospheric 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.

  13. The Impact of Geoengineering Aerosols on Stratospheric Temperature and Ozone

    NASA Technical Reports Server (NTRS)

    Heckendorn, P.; Weisenstein, D.; Fueglistaler, S.; Luo, B. P.; Rozanov, E.; Schraner, M.; Thomason, L. W.; Peter, T.

    2011-01-01

    Anthropogenic greenhouse gas emissions are warming 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 stratospheric 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 stratosphere. 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 stratospheric 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 stratospheric 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.

  14. The Impact of Geoengineering Aerosols on Stratospheric Temperature and Ozone

    NASA Technical Reports Server (NTRS)

    Heckendorn, P.; Weisenstein, D.; Fueglistaler, S.; Luo, B. P.; Rozanov, E.; Schraner, M.; Peter, T.; Thomason, L. W.

    2009-01-01

    Anthropogenic greenhouse gas emissions are warming 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 stratospheric 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 stratosphere. 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 stratospheric 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 stratospheric 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.

  15. Modifications of the Quasi-biennial Oscillation by a Geoengineering Perturbation of the Stratospheric Aerosol Layer

    NASA Technical Reports Server (NTRS)

    Aquila, V.; Garfinkel, C. I.; Newman, P. A.; Oman, L. D.; Waugh, D. W.

    2014-01-01

    This paper examines the impact of geoengineering via stratospheric 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 stratospheric aerosol burden, the lower tropical stratosphere is locked into a permanent westerly QBO phase. This locked QBO westerly phase is caused by the increased aerosol heating and associated warming in the tropical lower stratosphere.

  16. Stratospheric polar vortex splits and displacements in the high-top CMIP5 climate models

    NASA Astrophysics Data System (ADS)

    Seviour, William J. M.; Gray, Lesley J.; Mitchell, Daniel M.

    2016-02-01

    Sudden stratospheric warming (SSW) events can occur as either a split or a displacement of the stratospheric polar vortex. Recent observational studies have come to different conclusions about the relative impacts of these two types of SSW upon surface climate. A clearer understanding of their tropospheric impact would be beneficial for medium-range weather forecasts and could improve understanding of the physical mechanism for stratosphere-troposphere coupling. Here we perform the first multimodel comparison of stratospheric polar vortex splits and displacements, analyzing 13 stratosphere-resolving models from the fifth Coupled Model Intercomparison Project (CMIP5) ensemble. We find a wide range of biases among models in both the mean state of the vortex and the frequency of vortex splits and displacements, although these biases are closely related. Consistent with observational results, almost all models show vortex splits to occur barotropically throughout the depth of the stratosphere, while vortex displacements are more baroclinic. Vortex splits show a slightly stronger North Atlantic surface signal in the month following onset. However, the most significant difference in the surface response is that vortex displacements show stronger negative pressure anomalies over Siberia. This region is shown to be colocated with differences in tropopause height, suggestive of a localized response to lower stratospheric potential vorticity anomalies.

  17. The persistently variable "background" stratospheric aerosol layer and global climate change.

    PubMed

    Solomon, S; Daniel, J S; Neely, R R; Vernier, J-P; Dutton, E G; Thomason, L W

    2011-08-12

    Recent measurements demonstrate that the "background" stratospheric aerosol layer is persistently variable rather than constant, even in the absence of major volcanic eruptions. Several independent data sets show that stratospheric aerosols have increased in abundance since 2000. Near-global satellite aerosol data imply a negative radiative forcing due to stratospheric aerosol changes over this period of about -0.1 watt per square meter, reducing the recent global warming that would otherwise have occurred. Observations from earlier periods are limited but suggest an additional negative radiative forcing of about -0.1 watt per square meter from 1960 to 1990. Climate model projections neglecting these changes would continue to overestimate the radiative forcing and global warming in coming decades if these aerosols remain present at current values or increase.

  18. Numerical simulation of the gravitational separation in the stratosphere

    NASA Astrophysics Data System (ADS)

    Sugawara, S.; Ishidoya, S.; Morimoto, S.; Aoki, S.; Nakazawa, T.; Honda, H.; Murayama, S.

    2012-12-01

    It has been shown that the gravitational separation effect in the stratosphere 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 stratospheric circulation. In this study, theoretical simulations were performed to validate an existence of the gravitational separation in the stratosphere, 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 stratosphere. 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 stratosphere, 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 stratosphere. 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 stratosphere 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 stratospheric 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 warming. The relationships between the two variables under the enhanced-BDC condition are clearly different from those under the normal condition, indicating that

  19. IRTF/TEXES observations of Saturn’s stratospheric beacon

    NASA Astrophysics Data System (ADS)

    Fouchet, Thierry; Greathouse, T. K.; Richter, M. J.; Lacy, J.; Fletcher, L.; Spiga, A.

    2013-10-01

    On December 5th, 2010, a giant convective storm erupted in Saturn’s Northern Hemisphere as each Saturnian year at least since 1876. For the first time, a huge thermal and chemical stratospheric disturbance associated with this large convective event was detected from ground-based and Cassini observations (Fletcher et al. 2011). This stratospheric disturbance is named the beacon. Here, we present high spectral resolution observations of the beacon obtained by the Texas Echelon Cross Echelle Spectrograph (TEXES) mounted on the IRTF during 6 nights from July 15th, 2011 to July 20th, 2011. We targeted several different CH4 lines between 1230 and 1280 cm-1, probing the stratospheric temperature between 5 hPa and 0.05 hPa, and the H2 S(1) quadrupolar and collision-induced lines at 587 cm-1, probing the stratospheric temperature between 150 hPa and 5 hPa. The stratospheric temperatures are retrieved from the dataset using a forward radiative model coupled with a constrained linear inverse method. Within the core of the beacon the maximum temperature inferred from the data is 178K at 40°N, hence about 50K warmer than the mean temperature measured before the occurrence of the storm. However, the TEXES data unambiguously demonstrate that this warming is not vertically homogeneous but rather confined in a specific pressure range between 1-5 hPa, overhung by a cold layer between 0.1 and 1 hPa. This vertical behavior is evident from the CH4 line spectral profiles with the core of the lines in absorption and the wings in emission. Moreover, our data demonstrate that the altitude of the local temperature maximum increases northwards. We will present how this thermal structure can help deciphering the stratospheric heating sources. On the western side of the beacon, the stratospheric heating is concentrated at lower pressures, hence higher altitudes, than within the beacon, between 0.1 and 0.01 hPa. We interpret this structure as being caused by convective motions within the

  20. Global warming

    NASA Astrophysics Data System (ADS)

    Houghton, John

    2005-06-01

    'Global warming' 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 warming are changes of climate. The basic science of the 'greenhouse effect' that leads to the warming 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 warming 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.

  1. Project Together into the Stratosphere

    NASA Astrophysics Data System (ADS)

    Lenza, L.; Kapus, J.; Zavodsky, O.; Erdziak, J.; Zitka, J.; Kizek, R.; Peciva, T.

    2015-09-01

    Stratosphere 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 stratosphere". 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 stratosphere, 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 stratospheric platform and tests of GPS.

  2. Recent volcanism and the stratosphere.

    PubMed

    Cronin, J F

    1971-05-21

    In the quiet years after the 1956 eruption of the Bezymianny volcano in central Kamchatka, it is doubtful that any volcano vented into the stratosphere until the 1963 eruptions of Agung (Bali), Trident (Alaska), and Surtsey (Iceland). From 1963 to the Hekla (Iceland) event in May 1970, two latitudinal belts of volcanoes have ejected ash and gases into the stratosphere. One belt is equatorial and the other is just below the Arctic Circle. The latter, where the tropopause is considerably lower, may have been the principal source of replenishment of volcanic dust and gases to the stratosphere. Submarine and phreatic volcanic eruptions may have been the sources of reported increase of water vapor in the stratosphere.

  3. Thermal modeling of stratospheric airships

    NASA Astrophysics Data System (ADS)

    Wu, Jiangtao; Fang, Xiande; Wang, Zhenguo; Hou, Zhongxi; Ma, Zhenyu; Zhang, Helei; Dai, Qiumin; Xu, Yu

    2015-05-01

    The interest in stratospheric 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 stratospheric airships, while there is no systematic review on this aspect found yet. This paper presents a comprehensive literature review on thermal issues of stratospheric airships. The main challenges of thermal issues on stratospheric 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.

  4. Stratospheric dynamics and transport studies

    NASA Technical Reports Server (NTRS)

    Grose, William L.; Turner, R. E.; Blackshear, W. T.; Eckman, R. S.

    1990-01-01

    A three dimensional General Circulation Model/Transport Model is used to simulate stratospheric circulation and constituent distributions. Model simulations are analyzed to interpret radiative, chemical, and dynamical processes and their mutual interactions. Concurrent complementary studies are conducted using both global satellite data and other appropriate data. Comparisons of model simulations and data analysis studies are used to aid in understanding stratospheric dynamics and transport processes and to assess the validity of current theory and models.

  5. Signal of central Pacific El Niño in the Southern Hemispheric stratosphere during austral spring

    NASA Astrophysics Data System (ADS)

    Yang, Chengyun; Li, Tao; Dou, Xiankang; Xue, Xianghui

    2015-11-01

    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) stratosphere particularly during the austral spring. SH stratosphere warming is at a maximum in September rather than in November and December, as suggested by previous studies. SH stratospheric 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 stratospheric 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 stratospheric 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 warming and tropical cooling in the stratosphere. 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 stratosphere in both August and September and subsequently weaken during the following months.

  6. Universal stratospheric balloon gradiometer

    NASA Astrophysics Data System (ADS)

    Tsvetkov, Yury; Filippov, Sergey; Brekhov, Oleg; Nikolaev, Nikolay

    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 stratospheric 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 - stratospheric 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

  7. Stratospheric changes caused by geoengineering applications: potential repercussions and uncertainties

    NASA Astrophysics Data System (ADS)

    Kenzelmann, P.; Weisenstein, D.; Peter, T.; Luo, B. P.; Rozanov, E.; Fueglistaler, S.; Thomason, L. W.

    2009-04-01

    Anthropogenic greenhouse gas emissions tend to warm 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 stratosphere, for example by sulphur dioxide injections, part of the anthropogenic climate warming 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 warming of the tropical tropopause and consequently the increase of the amount of stratospheric 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 stratosphere. The results serve as input for the 3D chemistry-climate model SOCOL, which allows calculating the aerosol effect on stratospheric 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 stratosphere 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

  8. Superpressure stratospheric vehicle

    SciTech Connect

    Chocol, C.; Robinson, W.; Epley, L.

    1990-09-15

    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 stratosphere 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.

  9. POST: Polar Stratospheric Telescope

    NASA Astrophysics Data System (ADS)

    Bely, Pierre Y.; Ford, Holland C.; Burg, Richard; Petro, Larry; White, Rick; Bally, John

    1995-10-01

    The tropopause, typically at 16 to 18 km altitude at the lower latitudes, dips to 8 km in the polar regions. This makes the cold, dry and nonturbulent lower stratosphere accessible to tethered aerostats. Tethered aerostats can fly as high as 12 km and are extremely reliable, lasting for many years. In contrast to free-flying balloons, they can stay on station for weeks at a time, and payloads can be safely recovered for maintenance and adjustment and relaunched in a matter of hours. We propose to use such a platform, located first in the Arctic (near Fairbanks, Alaska) and, potentially, later in the Antarctic, to operate a new technology 6-meter, diluted aperture telescope with diffraction-limited performance in the near infrared. Thanks to the low ambient temperature (220 K), thermal emission from the optics is of the same order as that of the zodiacal light in the 2 to 3 micron band. Since this wavelength interval is the darkest part of the zodiacal light spectrum from optical wavelengths to 100 microns, the combination of high resolution images and a very dark sky make it the spectral region of choice for observing the redshifted light from galaxies and clusters of galaxies at moderate to high redshifts.

  10. Stratospheric processes: Observations and interpretation

    NASA Technical Reports Server (NTRS)

    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.

    1991-01-01

    Explaining the observed ozone trends discussed in an earlier update and predicting future trends requires an understanding of the stratospheric processes that affect ozone. Stratospheric 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 stratospheric processes is to describe the causes for the observed ozone trends as they are currently understood. At present, we understand with considerable confidence the stratospheric 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 stratospheric processes since the last assessment (World Meteorological Organization (WMO), 1990), and is not a complete review of all the new information about stratospheric processes. It begins with an update of the previous assessment of polar stratospheres (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.

  11. Modeled impacts of stratospheric ozone and water vapor perturbations with implications for high-speed civil transport aircraft

    SciTech Connect

    Rind, D.; Lonergan, P.

    1995-04-20

    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 stratospheric 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 stratosphere without allowing sea surface temperatures to change results in in situ cooling of up to 10{degrees}C in the tropical lower stratosphere, with radiative warming about half as large in the middle stratosphere. The temperature changes induce increases in tropospheric and lower stratospheric eddy energy and in the lower stratosphere 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 Stratospheric Aircraft reports, the stratosphere 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 stratospheric 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 stratospheric 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 stratospheric 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.

  12. Optimizing stratospheric sulfur geoengineering by seasonally changing sulfur injections

    NASA Astrophysics Data System (ADS)

    Laakso, Anton; Partanen, Antti-Ilari; Kokkola, Harri; Lehtinen, Kari; Korhonen, Hannele

    2015-04-01

    Solar radiation management (SRM) by stratospheric sulfur injection has been shown to have potential in counteracting global warming if reducing of greenhouse gases has not been achieved fast enough and if climate warming will continue. Injecting large amounts of sulfate particles to the stratosphere 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, stratospheric 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 stratosphere 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

  13. Long-wave stratospheric transmission of Mount St. Helens ejecta

    SciTech Connect

    Kuhn, P.M.; Haughney, L.C.; Innis, R.C.

    1981-01-01

    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, stratospheric infrared optical depth of 0.06. Assumptions on particle size, shortwave albedo, and thermal warming imply little surface temperature change caused by the ejecta on the third day immediately following the eruption.

  14. Long-wave stratospheric transmission of Mount St. Helens ejecta.

    PubMed

    Kuhn, P M; Haughney, L C; Innis, R C

    1981-01-01

    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-microm 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, stratospheric infrared optical depth of 0.06. Assumptions on particle size, shortwave albedo, and thermal warming imply little surface temperature change caused by the ejecta on the third day immediately following the eruption.

  15. Condensed Acids In Antartic Stratospheric Clouds

    NASA Technical Reports Server (NTRS)

    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.

    1992-01-01

    Report dicusses nitrate, sulfate, and chloride contents of stratospheric aerosols during 1987 Airborne Antarctic Ozone Experiment. Emphasizes growth of HNO3*3H2O particles in polar stratospheric clouds. Important in testing theories concerning Antarctic "ozone hole".

  16. Measurement of Elements in the Stratosphere

    NASA Technical Reports Server (NTRS)

    Anderson, J. G.

    1985-01-01

    Balloon-borne winch system; stratospheric free radicals; stratospheric sounding; copper vapor lasers; ozone measurement; NO2 analysis; chlorine chemistry; trace elements; and ClO observations are discussed.

  17. Influence of Stratosphere Troposphere Exchange on the Ozone Levels in India

    NASA Astrophysics Data System (ADS)

    Ganguly, Nandita; Tzanis, Chris

    2012-07-01

    Decrease in stratospheric ozone will result in an amplification of the solar ultraviolet B radiation reaching the ground, which is a threat to the human society. On the other hand, ozone being toxic to the living system and an important contributor to anthropogenic global warming, high levels of tropospheric ozone will have adverse effects on the air quality and climate. Transport of ozone from the stratosphere to the troposphere will cause stratospheric ozone to decrease and tropospheric ozone to increase, which can in turn have serious consequences for life on earth. Stratosphere-Troposphere Exchange (STE) is regarded as an important factor controlling the budget of ozone in the troposphere and lower stratosphere. Study of STE events in India are so far restricted to coordinated campaigns and measurements over longer periods are relatively scarce. In the light of this observation, the paper is aimed to identify the Indian latitudes, which are most likely to be affected by STE, the frequency of occurrence of shallow and deep STE events and the depth up to which stratospheric ozone descends into the troposphere during these events over the period of 24 years. In addition, the contribution of STE events to the observed high surface ozone levels for cities covering from north to south of India will be presented.

  18. Forecast experiments with the NASA/GLA stratospheric/tropospheric data assimilation system

    NASA Technical Reports Server (NTRS)

    Takano, Kenji; Baker, Wayman E.; Kalnay, Eugenia; Lamich, David J.; Rosenfield, Joan E.

    1987-01-01

    For the first time, a four-dimensional stratospheric/tropospheric data assimilation system with a top analysis level at 0.4 mb has been developed and used to produce physically consistent gridded analyses for the stratosphere as well as the troposphere for a period during the First GARP Global Experiment (FGGE) and Limb Infrared Monitor of the Stratosphere (LIMS) (November 1978-May 1979). The system consists of a two-dimensional optimum interpolation analysis with 18 mandatory pressure levels and a 19-level fourth order stratospheric/tropospheric general circulation model with a horizontal resolution of 4 (latitude) by 5 deg (longitude) and a top at 0.3 mb. The system allows the utilization of stratospheric data including LIMS, Tiros-N retrievals, rocketsondes and vertical temperature profile radiometer soundings in addition to the other FGGE level 2b data. These data are analyzed every six hours. In order to examine the quality of the analyzed data, forecast experiments starting from different analyses are performed for the period of the stratospheric sudden warming of late February 1979. The results indicate that by employing the present four-dimensional assimilation approach, the medium-range forecast skill for this event is improved.

  19. Light Absorption of Stratospheric Aerosols: Long-Term Trend and Contribution by Aircraft

    NASA Technical Reports Server (NTRS)

    Pueschel , R. F.; Gore, Waren J. Y. (Technical Monitor)

    1997-01-01

    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 stratosphere in 1981, followed by Clarke in 1983 and Pueschel in 1992. Because most stratospheric 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 stratospheric soot and sulfuric acid aerosol implicate aircraft as a source of stratospheric pollution. Because the strongly light-absorbing soot and the predominantly light-scattering sulfuric acid aerosol increase at similar rates, however, the mid-visible stratospheric aerosol single scatter albedo is expected to remain constant and not approach a critical value of 0.98 at which stratospheric cooling could change to warming.

  20. Age of stratospheric air unchanged within uncertainties over the past 30years

    NASA Astrophysics Data System (ADS)

    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.

    2009-01-01

    The rising abundances of greenhouse gases in the atmosphere is associated with an increase in radiative forcing that leads to warming of the troposphere, the lower portion of the Earth's atmosphere, and cooling of the stratosphere above. A secondary effect of increasing levels of greenhouse gases is a possible change in the stratospheric circulation, which could significantly affect chlorofluorocarbon lifetimes, ozone levels and the climate system more generally. Model simulations have shown that the mean age of stratospheric 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 stratospheric 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 stratospheric ozone levels, and of the coupling between ozone and climate change, a correct description of stratospheric transport and possible changes in the transport pathways are necessary.

  1. Observational evidence of preferred flow regimes in the Northern Hemisphere winter stratosphere

    NASA Technical Reports Server (NTRS)

    Pierce, R. B.; Fairlie, T. D. A.

    1993-01-01

    Ten years of stratospheric geopotential height data are analyzed in an attempt to determine whether there are preferred flow regimes in the Northern Hemisphere winter stratosphere. The data are taken from Stratospheric Sounding Units on board NOAA satellites. The probability density estimate of the amplitude of the wavenumber 1 10-mb height is found to be bimodal. The density distribution is composed of a dominant large-amplitude mode and a less frequent low-amplitude mode. When the wavenumber 1 10-mb height data are projected onto the phase plane defined by the 10-mb zonal-mean winds and wavenumber 1 100-mb heights, three preferred regimes are evident. The small-amplitude mode separates into a strong zonal wind-weak wave regime and a weak zonal wind-weak wave regime. The large-amplitude mode is an intermediate zonal wind-strong wave regime. Transitions between the large-amplitude regime and the weak zonal wind-weak wave regime are found to be associated with major stratospheric warmings. The clustering of the stratospheric data into the preferred flow regimes is interpreted in light of the bifurcation properties of the Holton and Mass model. The interannual variability of the Northern Hemisphere winter stratosphere is interpreted in terms of the relative frequency of the observed preferred regimes.

  2. Stratospheric meteorological conditions in the Arctic polar vortex, 1991 to 1992

    NASA Technical Reports Server (NTRS)

    Newman, P.; Lait, L. R.; Schoeberl, M.; Nash, E. R.; Kelly, K.; Fahey, D. W.; Nagatani, R.; Toohey, D.; Avallone, L.; Anderson, J.

    1993-01-01

    Stratospheric meteorological conditions during the Airborne Arctic Stratospheric Expedition II (AASE II) presented excellent observational opportunities from Bangor, Maine, because the polar vortex was located over southeastern Canada for significant periods during the 1991-1992 winter. Temperature analyses showed that nitric acid trihydrates (NAT temperatures below 195 K) should have formed over small regions in early December. The temperatures in the polar vortex warmed beyond NAT temperatures by late January (earlier than normal). Perturbed chemistry was found to be associated with these cold temperatures.

  3. Stratospheric ethane on Neptune - Comparison of groundbased and Voyager IRIS retrievals

    NASA Technical Reports Server (NTRS)

    Kostiuk, Theodor; Romani, Paul; Espenak, Fred; Bezard, Bruno

    1992-01-01

    Near-simultaneous ground and spacecraft measurements of 12-micron ethane emission spectra during the Voyager encounter with Neptune have furnished bases for the determination of stratospheric ethane abundance and the testing and constraining of Neptune methane-photochemistry models. The ethane retrievals were sensitive to the thermal profile used. Contribution functions for warm thermal profiles peaked at higher altitudes, as expected, with the heterodyne functions covering lower-pressure regions. Both constant- and nonconstant-with-height profiles remain candidate distributions for Neptune's stratospheric ethane.

  4. Chemistry and Pollution of the Stratosphere.

    ERIC Educational Resources Information Center

    Donovan, R. J.

    1978-01-01

    Presents an outline of the chemistry involved and the steps which are being taken to gain a better understanding of the stratosphere. Chemical composition of natural stratosphere and depletion of ozone in the stratosphere by man-made pollutants are covered. (HM)

  5. Statistical Perspectives on Stratospheric Transport

    NASA Technical Reports Server (NTRS)

    Sparling, L. C.

    1999-01-01

    Long-lived tropospheric source gases, such as nitrous oxide, enter the stratosphere through the tropical tropopause, are transported throughout the stratosphere by the Brewer-Dobson circulation, and are photochemically destroyed in the upper stratosphere. These chemical constituents, or "tracers" can be used to track mixing and transport by the stratospheric winds. Much of our understanding about the stratospheric 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 stratospheric 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

  6. Extreme stratospheric springs and their consequences for the onset of polar mesospheric clouds

    NASA Astrophysics Data System (ADS)

    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.

    2015-09-01

    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) stratospheric 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 warm springtime stratosphere; conversely, we show that the late onset in 2008 coincides with a very cold springtime stratosphere. Similar stratospheric 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 stratospheric 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 stratospheric 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 stratospheric FrIAC occurrences represents a new mode of coupling between the stratosphere 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.

  7. Onset of circulation anomalies during stratospheric vortex weakening events: the role of planetary-scale waves

    NASA Astrophysics Data System (ADS)

    Son, Seok-Woo; Martineau, Patrick

    2015-04-01

    transient wave propagation. Overall results are also compared with vertical coupling associated with weak polar vortex events such as stratospheric sudden warming events.

  8. Measurements of chlorine partitioning in the winter Arctic stratosphere

    NASA Astrophysics Data System (ADS)

    Stachnik, Robert A.; Salawitch, Ross; Engel, Andreas; Schmidt, Ulrich

    Measurements of the concentration profiles of key stratospheric reactive, reservoir and source gases, ClO, O3, HCl, N2O and CCl2F2, were made during two balloon flights in the Arctic on 27 January and 08 March 1995 that were part of the Second European Stratospheric Arctic and Mid-latitude Experiment (SESAME). On 27 January, low abundances of HCl (∼250 ppt at 50 hPa) were measured in air parcels that had been at temperatures below the type I PSC existence threshold accompanied by high concentrations of ClO (1.6 ppb at 50 hPa). Calculations using the currently recommended photochemical data yield a ratio of [ClO]+2[Cl2O2]+[HCl] to [Cly] near unity in these air parcels. The 08 March flight sampled warm stratospheric conditions outside the vortex with normal mid-latitude ClO (<100ppt at 50 hPa) and HCl abundances comprising about half of the available chlorine at 50 hPa.

  9. How stratospheric are deep stratospheric intrusions? LUAMI 2008

    NASA Astrophysics Data System (ADS)

    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

    2016-07-01

    A large-scale comparison of water-vapour vertical-sounding instruments took place over central Europe on 17 October 2008, during a rather homogeneous deep stratospheric 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 stratosphere 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 stratosphere. The data suggest an increase of ozone from the lower to the higher edge of the intrusion layer. This behaviour is also confirmed by stratospheric 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 stratosphere just above the dynamical tropopause, for the first time confirming the conclusions in "Part 1" from the Zugspitze CO observations. The trajectories qualitatively explain

  10. A dehydration mechanism for the stratosphere

    NASA Technical Reports Server (NTRS)

    Danielsen, E. F.

    1982-01-01

    Although mean circulations are generally credited with dehydration of the earth's stratosphere, convective instability in the tropics converts mean circulations to small residuals of local convective circulations. The effects of large cumulonimbus which penetrate the stratosphere and form huge anvils in the lower stratosphere are discussed with respect to hydration and dehydration of the stratosphere. Radiative heating at anvil base combined with cooling at anvil top drives a dehydration engine considered essential to explain the dry stratosphere. Seasonal and longitudinal variations in dehydration potentials are examined with maximum potential attributed to Micronesian area during winter and early spring.

  11. Aircraft deployment, and airborne arctic stratospheric expedition

    NASA Technical Reports Server (NTRS)

    Condon, Estelle; Tuck, Adrian; Hipskind, Steve; Toon, Brian; Wegener, Steve

    1990-01-01

    The Airborne Arctic Stratospheric Expedition had two primary objectives: to study the production and loss mechanisms of ozone in the north polar stratosphere and to study the effect on ozone distribution of the Arctic Polar Vortex and of the cold temperatures associated with the formation of Polar Stratospheric Clouds. Two specially instrumented NASA aircraft were flown over the Arctic region. Each aircraft flew to acquire data on the meteorological, chemical and cloud physical phenomena that occur in the polar stratosphere during winter. The chemical processes which occur in the polar stratosphere during winter were also observed and studied. The data acquired are being analyzed.

  12. POST: a polar stratospheric telescope

    NASA Astrophysics Data System (ADS)

    Ford, Holland C.; Bely, Pierre Y.; Bally, John; Crocker, James H.; Dopita, Mike; Tilley, James N.; Allen, Ronald; Bartko, Frank; White, Richard L.; Burg, Richard; Burrows, Christopher J.; Clampin, Mark; Harper, Doyal A.; Illingworth, Garth; McCray, Richard; Meyer, Stephan; Mould, Jeremy; Norman, Colin

    1994-06-01

    The lower stratosphere in the polar regions offers conditions for observation in the near-infrared comparable to those obtained from space. We describe a concept for a 6-meter, diluted aperture, near-infrared telescope carried by a tethered aerostat flying at 12 km altitude, to serve as a testbed for future space astronomical observatories while producing frontier science.

  13. Sampling stratospheric aerosols with impactors

    NASA Technical Reports Server (NTRS)

    Oberbeck, Verne R.

    1989-01-01

    Derivation of statistically significant size distributions from impactor samples of rarefield stratospheric aerosols imposes difficult sampling constraints on collector design. It is shown that it is necessary to design impactors of different size for each range of aerosol size collected so as to obtain acceptable levels of uncertainty with a reasonable amount of data reduction.

  14. 21 Layer troposphere-stratosphere climate model

    NASA Technical Reports Server (NTRS)

    Rind, D.; Suozzo, R.; Lacis, A.; Russell, G.; Hansen, J.

    1984-01-01

    The global climate model is extended through the stratosphere by increasing the vertical resolution and raising the rigid model top to the 0.01 mb (75 km) level. The inclusion of a realistic stratosphere is necessary for the investigation of the climate effects of stratospheric perturbations, such as changes of ozone, aerosols or solar ultraviolet irradiance, as well as for studying the effect on the stratosphere of tropospheric climate changes. The observed temperature and wind patterns throughout the troposphere and stratosphere are simulated. In addition to the excess planetary wave amplitude in the upper stratosphere, other model deficiences include the Northern Hemisphere lower stratospheric 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.

  15. Long-Term Variability of Stratospheric Temperature Above Central Antarctica

    NASA Astrophysics Data System (ADS)

    Shirochkov, A.; Makarova, L.

    geographic poles stratospheric temperature had obvious tendency to warming in 1972-1995. On the other hand , the correspondent Vostok data demonstrate clear tendency to cooling in this period. Possible explanations of these results are given.

  16. Ultraviolet Radiation and Stratospheric Ozone

    NASA Technical Reports Server (NTRS)

    Stolarski, R.

    2003-01-01

    Ultraviolet radiation from the sun produces ozone in the stratosphere 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 stratosphere 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 stratospheric 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 stratosphere downward to the lower stratosphere. 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.

  17. The Unusual Southern Hemisphere Stratosphere Winter of 2002

    NASA Technical Reports Server (NTRS)

    Newman, Paul A.; Nash, Eric R.

    2003-01-01

    The southern hemisphere stratospheric 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 warming 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 stratospheric warming 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.

  18. The climatic effects of the direct injection of water vapour into the stratosphere by large volcanic eruptions

    NASA Astrophysics Data System (ADS)

    Joshi, M. M.; Jones, G. S.

    2009-03-01

    We describe a novel mechanism that can significantly lower the amplitude of the climatic response to certain large volcanic eruptions. The proximity of oceans to some volcanoes can cause significant entrainment of water into coignimbrite clouds during the eruption. If sufficiently large amounts of this entrained water vapour enter the stratosphere, a climatically significant amount of water vapour can be left over in the lower stratosphere after the eruption, even after sulphate aerosol formation. This excess stratospheric humidity warms the climate, and acts to balance the climatic cooling induced by the volcanic aerosol, especially because the humidity anomaly lasts for a period that is longer that the residence time of aerosol in the stratosphere. In particular, Northern Hemisphere cooling is reduced in magnitude. We discuss this mechanism in the context of the discrepancy between the observed and modelled cooling following the Krakatau eruption in 1883.

  19. Stratospheric Temperatures and Water Loss from Moist Greenhouse Atmospheres of Earth-like Planets

    NASA Astrophysics Data System (ADS)

    Kasting, James F.; Chen, Howard; Kopparapu, Ravi K.

    2015-11-01

    A radiative-convective climate model is used to calculate stratospheric temperatures and water vapor concentrations for ozone-free atmospheres warmer than that of modern Earth. Cold, dry stratospheres are predicted at low surface temperatures, in agreement with recent 3D calculations. However, at surface temperatures above 350 K, the stratosphere warms 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.

  20. STRATOSPHERIC TEMPERATURES AND WATER LOSS FROM MOIST GREENHOUSE ATMOSPHERES OF EARTH-LIKE PLANETS

    SciTech Connect

    Kasting, James F.; Kopparapu, Ravi K.; Chen, Howard E-mail: hwchen@bu.edu

    2015-11-01

    A radiative-convective climate model is used to calculate stratospheric temperatures and water vapor concentrations for ozone-free atmospheres warmer than that of modern Earth. Cold, dry stratospheres are predicted at low surface temperatures, in agreement with recent 3D calculations. However, at surface temperatures above 350 K, the stratosphere warms 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.

  1. Strong modification of stratospheric ozone forcing by cloud and sea-ice adjustments

    NASA Astrophysics Data System (ADS)

    Xia, Yan; Hu, Yongyun; Huang, Yi

    2016-06-01

    We investigate the climatic impact of stratospheric 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 warming (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 stratosphere-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 stratospheric ozone perturbation, which constitutes a significant radiative adjustment that influences the sign and magnitude of the global surface temperature change.

  2. Halocarbon ozone depletion and global warming potentials

    NASA Technical Reports Server (NTRS)

    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.

    1990-01-01

    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 stratospheric 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 stratosphere 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 stratospheric ozone and global climate (through 'greenhouse' global warming).

  3. Policies on global warming and ozone depletion

    SciTech Connect

    Green, B.

    1987-04-01

    The recent discovery of a dramatic seasonal drop in the amount of ozone over Antarctica has catalyzed concern for protection of stratospheric 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 warming 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 warming, 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.

  4. Winter warming from large volcanic eruptions

    SciTech Connect

    Robock, A.; Jianping Mao )

    1992-12-24

    An examination of the Northern Hemisphere winter surface temperature patterns after the 12 largest volcanic eruptions from 1883-1992 shows warming over Eurasia and North America and cooling over the Middle East which are significant at the 95% 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 stratosphere by the volcanic aerosols is responsible for the regions of warming, while the cooling is caused by blocking of incoming sunlight. 21 refs., 2 figs., 1 tab.

  5. Mixtures of stratospheric and overshooting air measured using A-Train sensors

    NASA Astrophysics Data System (ADS)

    Iwasaki, S.; Shibata, T.; Okamoto, H.; Ishimoto, H.; Kubota, H.

    2012-06-01

    Synergetic spaceborne observations of overshooting air, defined as cloud intrusion through the level of neutral buoyancy above deep convection, are analyzed using various thresholds introduced in previous studies to detect overshooting. The brightness temperature of the overshooting air measured by the Moderate Resolution Imaging Spectroradiometer (MODIS) is generally 2 K higher than that retrieved by the radiative transfer model, in which the size distribution of ice cloud particles is estimated from Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) and CloudSat data and the vertical temperature profile of cloud is assumed to follow that of the European Centre for Medium Range Weather Forecast (ECMWF). The lapse rate of overshooting whose cloud top is higher than the level of the cold-point temperature (CPT) is lower than that of an adiabatic expansion. These observations can be rationalized as being due to the overshooting air being locally warmed by a mixture of warmer stratospheric air. Analysis of CALIOP and CloudSat data by using a radar-lidar algorithm shows that the mode of averaged ice water content of the overshoot above the CPT height is 6.3-10 mg/m3. Therefore, if 5% or more of ice particles in the overshoot are sublimated and mixed into the lower stratosphere, the lower stratospheric air will be hydrated. The difference between the brightness temperatures of 6.7 and 11 μm channels observed with MODIS demonstrates that the overshoot enhances stratospheric water vapor. These results indicate that the warm stratospheric air moves downward at and around the overshoot and mixes with the overshooting air and that the overshooting hydrates the lower stratosphere.

  6. Possible methane-induced polar warming in the early Eocene

    NASA Astrophysics Data System (ADS)

    Sloan, L. C.; Walker, James C. G.; Moore, T. C., Jr.; Rea, David K.; Zachos, James C.

    1992-05-01

    Estimates of Eocene wetland areas are considered and it is suggested that the flux of methane may have been substantially greater during the Eocene than at present. Elevated methane concentrations would have enhanced early Eocene global warming and also might have prevented severe winter cooling of polar regions because of the potential of atmospheric methane to promote the formation of optically thick polar stratospheric ice clouds.

  7. Quantifying the temperature-independent effect of stratospheric aerosol geoengineering on global-mean precipitation in a multi-model ensemble

    NASA Astrophysics Data System (ADS)

    Ferraro, Angus J.; Griffiths, Hannah G.

    2016-03-01

    The reduction in global-mean precipitation when stratospheric aerosol geoengineering is used to counterbalance global warming 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 stratospheric sulphate aerosol itself also acts to reduce global-mean precipitation independent of its effects on temperature. The temperature-independent effect of stratospheric 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 stratosphere 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 stratospheric 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 stratospheric warming the aerosol causes. Our results suggest climate model simulations of solar dimming can capture the main features of the global-mean precipitation response to stratospheric aerosol geoengineering.

  8. Artemis: A Stratospheric Planet Finder

    NASA Technical Reports Server (NTRS)

    Ford, H. C.; Petro, L. D.; Burrows, C.; Ftaclas, C.; Roggemann, M. C.; Trauger, J. T.

    2003-01-01

    The near-space environment of the stratosphere 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" Stratospheric 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.

  9. Stratospheric emissions effects database development

    NASA Technical Reports Server (NTRS)

    Baughcum, Steven L.; Henderson, Stephen C.; Hertel, Peter S.; Maggiora, Debra R.; Oncina, Carlos A.

    1994-01-01

    This report describes the development of a stratospheric 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 Stratospheric 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.

  10. Ices in Titan's Lower Stratosphere

    NASA Technical Reports Server (NTRS)

    Anderson, Carrie

    2010-01-01

    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 stratosphere, 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 stratosphere have been identified at latitudes south of 50N. Results and physical implications will be discussed.

  11. Freezing of stratospheric aerosol droplets

    NASA Astrophysics Data System (ADS)

    Luo, Beiping; Peter, Thomas; Crutzen, Paul

    Theoretical calculations are presented for homogeneous and heterogeneous freezing of sulfuric acid droplets under stratospheric 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 stratospheric clouds.

  12. Stratosphere-troposphere coupling, downward control, eddy feedbacks, and all that (Invited)

    NASA Astrophysics Data System (ADS)

    Birner, T.; Baldwin, M. P.; Thompson, D. W.

    2013-12-01

    Stratospheric variability, e.g. associated with sudden stratospheric warmings, can have substantial effects on surface weather and climate, especially at middle to high latitudes. Despite clear evidence of these impacts, the primary dynamics of such stratosphere-troposphere coupling are not yet well understood. A range of theories and proposed mechanisms exists, but none is fully conclusive. Here we show that the stratospheric meridional circulation forces the column of air above the Arctic downwards into the troposphere, acting like a mechanical plunger that controls the day-to-day thickness of the troposphere. Concurrently, isentropic surfaces undergo large coherent associated changes in the lower stratosphere and upper troposphere, in particular in their meridional slope, affecting tropopause-level baroclinicity. Furthermore, polar cap tropopause height and temperature show large associated changes. Raising and lowering of the Arctic tropopause layer leads to stretching and compression of the tropospheric column and a north-south dipole in surface pressure similar to the Northern Annular Mode. However, vortex stretching is found to severely overestimate the surface pressure response highlighting the importance of internal tropospheric eddy feedbacks. The response in tropopause potential temperature is found to be consistent with these tropospheric eddy feedbacks.

  13. Stratospheric sulfur and its implications for radiative forcing simulated by the chemistry climate model EMAC

    PubMed Central

    Brühl, C; Lelieveld, J; Tost, H; Höpfner, M; Glatthor, N

    2015-01-01

    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 stratospheric 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 stratosphere. 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 Stratospheric 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 stratospheric background aerosol including sulfate from COS and small contributions by DMS oxidation, and organic aerosol from biomass burning, is about 0.07W/m2. For stratospheric 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 warming, 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

  14. QBO Influence on Polar Stratospheric Variability in the GEOS Chemistry-Climate Model

    NASA Technical Reports Server (NTRS)

    Hurwitz, M. M.; Oman, L. D.; Li, F.; Slong, I.-S.; Newman, P. A.; Nielsen, J. E.

    2010-01-01

    The quasi-biennial oscillation modulates the strength of both the Arctic and Antarctic stratospheric 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 stratosphere in winter. While the Antarctic stratosphere is less variable, recent work has shown that Southern Hemisphere planetary wave driving increases in response to "warm 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 stratospheric 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 stratospheric 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.

  15. Stratospheric sulfur and its implications for radiative forcing simulated by the chemistry climate model EMAC

    NASA Astrophysics Data System (ADS)

    Brühl, C.; Lelieveld, J.; Tost, H.; Höpfner, M.; Glatthor, N.

    2015-03-01

    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 stratospheric 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 stratosphere. 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 Stratospheric 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 stratospheric background aerosol including sulfate from COS and small contributions by DMS oxidation, and organic aerosol from biomass burning, is about 0.07W/m2. For stratospheric 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 warming, 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.

  16. Antarctic BrO tropospheric and stratospheric columns during the spring of 2002

    NASA Astrophysics Data System (ADS)

    Johnston, P.; Thomas, A.; Schofield, R.; Kreher, K.; Connor, B.; Wood, S.; Shooter, D.; Chipperfield, M.; Richter, A.; von Glasow, R.; Rodgers, C.

    2005-12-01

    Catalytic ozone destruction cycles involving bromine account for ~80% of the stratospheric ozone losses over Antarctica. Also, BrO causes almost complete boundary layer ozone loss in the polar spring and has been linked to increased mercury deposition in the polar regions. Direct-sun and zenith-sky spectroscopic measurements were combined in a DOAS - optimal estimation retrieval of tropospheric and stratospheric BrO columns at different SZAs over the polar spring at Arrival Heights (77.8°S, 166.7°E), Antarctica, in 2002, the year in which there was an unprecedented early warming of the stratosphere which caused a split and weakening of the vortex. Twenty one clear sky twilight periods were investigated and column retrievals were made at SZAs 80°, 84° and 88°. A high BrO `explosion' event that was detected in the tropospheric column retrievals is shown. Comparison of measured tropospheric columns with tropospheric BrO model calculations is made, as is a comparison of stratospheric column measurements with stratospheric BrO model calculations from SLIMCAT. Finally, comparisons of the retrieved total columns are made with columns measured by the GOME satellite.

  17. Chlorine compounds and stratospheric ozone

    NASA Technical Reports Server (NTRS)

    Cicerone, R. J.; Walters, S.; Stolarski, R. S.

    1975-01-01

    A report by Cicerone et al. (1974) concerned with the potential size of the atmospheric perturbation produced by man-made chlorofluoromethanes is considered, giving attention to a number of errors made in the first investigation and their correction. However, the corrections do not significantly change the results reported. It had been found that chlorine oxides which arise from chlorofluoromethane usage will within 10 or 15 years provide a sink for stratospheric ozone which will dominate the natural sinks for ozone.

  18. Evidence for an earlier greenhouse cooling effect in the stratosphere before 1980 over the Northern Hemisphere

    NASA Astrophysics Data System (ADS)

    Zerefos, C. S.; Tourpali, K.; Zanis, P.; Eleftheratos, K.; Repapis, C.; Goodman, A.; Wuebbles, D.; Isaksen, I. S. A.; Luterbacher, J.

    2014-08-01

    This study provides a new look at the observed and calculated long-term temperature changes from the lower troposphere to the lower stratosphere 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 stratospheric data set of geopotential height data since 1957. This approach was followed to extend the records for the investigation of the stratospheric 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 warming (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 stratosphere 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 stratosphere persists throughout the year from the tropics up to 60° N. At polar latitudes competing dynamical and radiative

  19. Changes in the Ozone Content over Central Europe During Reversals of Stratospheric Circulation in Late Winter

    NASA Technical Reports Server (NTRS)

    Entzian, G.; Grasnick, K. H.

    1984-01-01

    A superposed epoch analysis during late winter zonal wind reversals was carried out from 18 year observation series (1963 to 1980) of the meridional geopotential height gradient in the 30 mb level (latitude mean) and of the ozone content over central Europe. Experimental data suggest that if planetary waves are responsible for the additional meridional ozone transport during stratospheric warmings, this transport has to take place at heights other than those up to the ozone maximum in the middle latitudes.

  20. Raman-Augmented Stratospheric-Ozone Lidar

    NASA Technical Reports Server (NTRS)

    Mcdermid, I. Stuart

    1994-01-01

    Differential-absorption lidar (DIAL) system measures concentration of ozone in stratosphere augmented with subsystem measuring Raman scattering from nitrogen. One of number of DIAL systems used in long-term monitoring of stratospheric ozone. Raman scattering from nitrogen provides data to correct for effects of aerosols. Channels at wavelengths of 332 and 385 nm added to DIAL receiver to measure Raman backscattering from nitrogen molecules in stratosphere. Data-acquisition electronics sample photon counts at a rate of 250 MHz.

  1. Stratospheric Temperature Changes: Observations and Model Simulations

    NASA Technical Reports Server (NTRS)

    Ramaswamy, V.; Chanin, M.-L.; Angell, J.; Barnett, J.; Gaffen, D.; Gelman, M.; Keckhut, P.; Koshelkov, Y.; Labitzke, K.; Lin, J.-J. R.

    1999-01-01

    This paper reviews observations of stratospheric temperatures that have been made over a period of several decades. Those observed temperatures have been used to assess variations and trends in stratospheric 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 stratosphere 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 stratosphere, with a reduction in the cooling in mid-stratosphere (near 35 km), and increased cooling in the upper stratosphere (approximately 2 K per decade at 50 km). Model simulations indicate that the depletion of lower stratospheric ozone is the dominant factor in the observed lower stratospheric cooling. In the middle and upper stratosphere both the well-mixed greenhouse gases (such as CO) and ozone changes contribute in an important manner to the cooling.

  2. Temperature Trends in the Tropical Upper Troposphere and Lower Stratosphere: Connections with Sea Surface Temperatures and Implications for Water Vapor and Ozone

    NASA Technical Reports Server (NTRS)

    Garfinkel, C. I.; Waugh, D. W.; Oman, L. D.; Wang, L.; Hurwitz, M. M.

    2013-01-01

    Satellite observations and chemistry-climate model experiments are used to understand the zonal structure of tropical lower stratospheric temperature, water vapor, and ozone trends. The warming in the tropical upper troposphere over the past 30 years is strongest near the Indo-Pacific warm pool, while the warming trend in the western and central Pacific is much weaker. In the lower stratosphere, these trends are reversed: the historical cooling trend is strongest over the Indo-Pacific warm 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 stratospheric tropical temperature trends. Warming SSTs in the Indian Ocean and in the warm 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 stratosphere. 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 stratosphere. 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 stratosphere, 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.

  3. Seasonal evolution of Saturn's stratosphere

    NASA Astrophysics Data System (ADS)

    Sylvestre, Melody; Fouchet, Thierry; Spiga, Aymeric; Guerlet, Sandrine

    2015-11-01

    The exceptional duration of the Cassini-Huygens mission enables unprecedented study of Saturn's atmospheric dynamics and chemistry. In Saturn's stratosphere (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 stratosphere 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 stratospheres do not exhibit the same trends in their seasonal variations, especially for temperature. In the lower stratosphere, the seasonal temperature contrast is maximal (at 1 hPa) and can be explained by the radiative contributions included in our GCM. In contrast, upper stratospheric 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

  4. Inability of stratospheric sulfate aerosol injections to preserve the West Antarctic Ice Sheet

    NASA Astrophysics Data System (ADS)

    McCusker, K. E.; Battisti, D. S.; Bitz, C. M.

    2015-06-01

    Injection of sulfate aerosols into the stratosphere has the potential to reduce the climate impacts of global warming, 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 stratospheric sulfate aerosol concentrations after a period of global warming 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 stratospheric aerosol layer does not effectively counteract surface and upper level atmospheric circulation changes caused by increasing GHGs, resulting in continued upwelling of warm 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.

  5. The Met Office HadGEM3-ES chemistry-climate model: evaluation of stratospheric dynamics and its impact on ozone

    NASA Astrophysics Data System (ADS)

    Hardiman, Steven C.; Butchart, Neal; O'Connor, Fiona M.; Rumbold, Steven T.

    2017-03-01

    Free-running and nudged versions of a Met Office chemistry-climate model are evaluated and used to investigate the impact of dynamics versus transport and chemistry within the model on the simulated evolution of stratospheric ozone. Metrics of the dynamical processes relevant for simulating stratospheric ozone are calculated, and the free-running model is found to outperform the previous model version in 10 of the 14 metrics. In particular, large biases in stratospheric transport and tropical tropopause temperature, which existed in the previous model version, are substantially reduced, making the current model more suitable for the simulation of stratospheric ozone. The spatial structure of the ozone hole, the area of polar stratospheric clouds, and the increased ozone concentrations in the Northern Hemisphere winter stratosphere following sudden stratospheric warmings, were all found to be sensitive to the accuracy of the dynamics and were better simulated in the nudged model than in the free-running model. Whilst nudging can, in general, provide a useful tool for removing the influence of dynamical biases from the evolution of chemical fields, this study shows that issues can remain in the climatology of nudged models. Significant biases in stratospheric vertical velocities, age of air, water vapour, and total column ozone still exist in the Met Office nudged model. Further, these can lead to biases in the downward flux of ozone into the troposphere.

  6. Development of algorithms for using satellite meteorological data sets to study global transport of stratospheric aerosols and ozone

    NASA Technical Reports Server (NTRS)

    Want, P. H.; Deepak, A.

    1985-01-01

    The utilization of stratospheric aerosol and ozone measurements obtained from the NASA developed SAM II and SAGE satellite instruments were investigated for their global scale transports. The stratospheric aerosols showed that during the stratospheric warming 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 stratospheric ozone, large poleward ozone transports are shown to occur in the altitude region from 24 km to 38 km near 55N during this warming. 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 stratosphere 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.

  7. CFC Destruction of Ozone - Major Cause of Recent Global Warming!

    NASA Astrophysics Data System (ADS)

    Ashworth, R. A.

    2008-12-01

    There has been a lot of discussion about global warming. Some say anthropogenic carbon dioxide (CO2) emissions caused the earth to warm. Others say there is no abnormality at all, that it is just natural warming. As you will see from the data presented and analyzed, a greater than normal warming 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 warming. CFCs have created both unnatural atmospheric cooling and warming based on these facts: CFCs have destroyed ozone in the lower stratosphere/ 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-warming) cycle effect on the earth's temperature. The loss of ozone allowed more UV light to pass through the stratosphere at a sufficient rate to warm 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 stratosphere 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 warm 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, warmed like the rest of the Polar Regions; but south at Vostok, there has

  8. Tracking the delayed response of the northern winter stratosphere to ENSO using multi reanalyses and model simulations

    NASA Astrophysics Data System (ADS)

    Ren, Rongcai; Rao, Jian; Wu, Guoxiong; Cai, Ming

    2016-06-01

    The concurrent effects of the El Niño-Southern Oscillation (ENSO) on the northern winter stratosphere 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 stratosphere. The warm-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 stratosphere 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 stratosphere, which acts to intensify/weaken the climatological wave pattern during warm/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 stratosphere 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 stratospheric layer is still dominated by wavenumber-1, it is mainly caused by wavenumber-2 in the lower stratosphere. However, the wavenumber-2 activity in the next winter is always underestimated in the model simulations, and wavenumber-1 activity dominates in both winters.

  9. Troposphere-stratosphere dynamical coupling in the southern high latitudes and its linkage to the Amundsen Sea

    NASA Astrophysics Data System (ADS)

    England, Mark R.; Shaw, Tiffany A.; Polvani, Lorenzo M.

    2016-04-01

    Extremes in the distribution of Southern Hemisphere stratospheric 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 stratospheric 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 warming (cooling) over the Amundsen Bellingshausen Seas in reanalysis data. Since coupling to the stratosphere 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-stratosphere 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 stratospheric extremes exhibit robust biases in tropospheric sea level pressure variability over the Antarctic Peninsula. Models which fail to capture the extremes in stratospheric heat flux, significantly underestimate the variance of the distribution of mean sea level pressure anomalies over Western Antarctica.

  10. The natural oscillations in stratospheric ozone observed by the GROMOS microwave radiometer at the NDACC station Bern

    NASA Astrophysics Data System (ADS)

    Moreira, Lorena; Hocke, Klemens; Navas-Guzmán, Francisco; Eckert, Ellen; von Clarmann, Thomas; Kämpfer, Niklaus

    2016-08-01

    A multilinear parametric regression analysis was performed to assess the seasonal and interannual variations of stratospheric ozone profiles from the GROMOS (GROund-based Millimeter-wave Ozone Spectrometer) microwave radiometer at Bern, Switzerland (46.95° N, 7.44° E; 577 m). GROMOS takes part in the Network for the Detection of Atmospheric Composition Change (NDACC). The study covers the stratosphere from 50 to 0.5 hPa (from 21 to 53 km) and extends over the period from January 1997 to January 2015. The natural variability was fitted during the regression analysis through the annual and semi-annual oscillations (AO, SAO), the quasi-biennial oscillation (QBO), the El Niño-Southern Oscillation (ENSO) and the solar activity cycle. Seasonal ozone variations mainly appear as an annual cycle in the middle and upper stratosphere and a semi-annual cycle in the upper stratosphere. Regarding the interannual variations, they are primarily present in the lower and middle stratosphere. In the lower and middle stratosphere, ozone variations are controlled predominantly by transport processes, due to the long lifetime of ozone, whereas in the upper stratosphere its lifetime is relatively short and ozone is controlled mainly by photochemistry. The present study shows agreement in the observed naturally induced ozone signatures with other studies. Further, we present an overview of the possible causes of the effects observed in stratospheric ozone due to natural oscillations at a northern midlatitude station. For instance regarding the SAO, we find that polar winter stratopause warmings contribute to the strength of this oscillation since these temperature enhancements lead to a reduction in upper stratospheric ozone. We have detected a strong peak amplitude of about 5 % for the solar cycle in lower stratospheric ozone for our 1.5 cycles of solar activity. Though the 11-year ozone oscillation above Bern is in phase with the solar cycle, we suppose that the strong amplitude is

  11. Stratospheric Balloon Gradient Geomagnetic Measurements

    NASA Astrophysics Data System (ADS)

    Filippov, Sergey; Tsvetkov, Yury

    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 stratospheric 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). One of the examples of such sounding system have been designed, developed and maintained at IZMIRAN during already about 20 years. This system consists of three instrumental con-tainers uniformly placed along a vertical 6 km line. System allows measuring a module and vertical gradient of the geomagnetic field along the whole flight trajectory and so one's name is -stratospheric balloon magnetic gradiometer (SMBG). The GPS-receivers, located in each instrumental container, fix the flight coordinates to within several tens meters. Data trans-mission is carried out by Globalstar satellite link. The obtained data are used in solving the problems of deep sounding of the Earth's crust magnetic structure -an extraction of magnetic anomalies, determination of a depth of bedding of magnetoactive rocks and others. The developed launching technology, deployment in flight, assembly, data processing, transfer and landing the containers with the equipment can be used for other similar problems of monitoring and sounding an environment. Useful flight weights of each instrumental container may be reaching 50 kg. More than ten testing flights (1986-2009) at stratospheric altitudes (20-30 km) have proven the reliability of this system.

  12. Simulations of Dynamics and Transport during the September 2002 Antarctic Major Warming

    NASA Technical Reports Server (NTRS)

    Manney, Gloria L.; Sabutis, Joseph L.; Allen, Douglas R.; Lahoz, Willian A.; Scaife, Adam A.; Randall, Cora E.; Pawson, Steven; Naujokat, Barbara; Swinbank, Richard

    2005-01-01

    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 warming. The vortex split on approx.25 September; recovery after the warming, 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 warming, with zonal wind deceleration throughout the stratosphere at high latitudes before the vortex split, continuing in the middle and upper stratosphere 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 warmings, except that during this warming, 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 stratosphere, with a core region in the lower-stratospheric 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 warming, 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 warmings

  13. Changing Composition of the Global Stratosphere.

    ERIC Educational Resources Information Center

    McElroy, Michael B.; Salawitch, Ross J.

    1989-01-01

    Discusses the chemistry of the stratosphere 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 stratospheric ozone demonstrate that the global environment is fragile and is impacted by human…

  14. Mechanisms of Stratospheric Ozone Transport.

    DTIC Science & Technology

    1982-12-03

    amounts orcur too fat south and about 1 month too late. 92 CHANGE IN (740) (PPM) DIABATIC. cos ( LAT ) 70 50 ~40 (D 30_ _ _ _ _ ) 1 5 Ŗ 2.5 Z. 20 10 0 D...AD-A122 609 MECHANISMS OF STRATOSPHERIC OZONE BRANSPOR(U) NAVAL RESEARCH LAB WASHINGTON DC R B ROOD ET AL 03 DEC 82 UNCLASSIFIED F/G 4/ 1 ...NLIEIIIIEIIII EIIIIIIIIIIIIl IIIEIIIIIEEEEE IIIIIIIIIIIIIl EIIIIIIIIIIIIl EIIIIIIIIIIIIl 1111.0 112 M *0 MIt ROCLt RLS’OLU7ION TLST CHART - - - ,T 1 m -N ;’ V

  15. Total Ozone Prediction: Stratospheric Dynamics

    NASA Technical Reports Server (NTRS)

    Jackman, Charles H.; Kawa, S. Ramdy; Douglass, Anne R.

    2003-01-01

    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 stratospheric dynamics in the prediction of total ozone. The GCM predictions will be compared and contrasted with TOMS measurements.

  16. The Evolution and Fate of Saturn's Stratospheric Vortex: Infrared Spectroscopy from Cassini

    NASA Technical Reports Server (NTRS)

    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.

    2012-01-01

    The planet-encircling springtime storm in Saturn's troposphere (December 2010-July 2011) produced dramatic perturbations to stratospheric 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 stratospheric 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 warm 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 warm airmasses to form the large single 'stratospheric 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. Stratospheric 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 stratospheric vortices on other giant planets.

  17. Arctic stratospheric sulphur injections: radiative forcings and cloud responses

    NASA Astrophysics Data System (ADS)

    Lohmann, U.; Gasparini, B.; Miriam, K.; Kravitz, B.; Rasch, P. J.

    2014-12-01

    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 stratospheric 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 stratospheric 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 stratospheric sulphur injections in the absence of sulphate warming

  18. Stratospheric Cooling and Arctic Ozone Recovery

    NASA Technical Reports Server (NTRS)

    Danilin, Michael Y.; Sze, Nien-Dak; Ko, Malcolm K. W.; Rodriquez, Jose M.

    1998-01-01

    We present sensitivity studies using the AER( box model for an idealized parcel in the lower stratosphere at 70 N during winter/spring with different assumed stratospheric coolings and chlorine loadings. Our calculations show that stratospheric cooling could further deplete ozone via increased polar stratospheric 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 stratospheric 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.

  19. Stratospheric Cooling and Arctic Ozone Recovery

    NASA Technical Reports Server (NTRS)

    Danilin, Michael Y.; Sze, Nien-Dak; Ko, Malcolm K. W.; Rodriquez, Jose M.

    1998-01-01

    We present sensitivity studies using the AER box model for an idealized parcel in the lower stratosphere at 70 deg N during winter/spring with different assumed stratospheric cooling and chlorine loadings. Our calculations show that stratospheric cooling could further deplete ozone via increased polar stratospheric 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 stratospheric 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.

  20. The Airborne Arctic Stratospheric Expedition - Prologue

    NASA Technical Reports Server (NTRS)

    Turco, Richard; Plumb, Alan; Condon, Estelle

    1990-01-01

    This paper presents an introduction to the initial scientific results of the Airborne Arctic Stratospheric Expedition (AASE), as well as data from other atmospheric experiments and analyses carried out during the Arctic polar winter of 1989. Mission objectives of the AASE were to study the mechanisms of ozone depletion and redistribution in the northern polar stratosphere, including the influences of Arctic meteorology, and polar stratospheric clouds formed at low temperatures. Some major aspects of the AASE are described including: logistics and operations, meteorology, polar stratospheric clouds, trace composition and chemistry, and ozone depletion. It is concluded that the Arctic-89 experiments have provided the scientific community with a wealth of new information that will contribute to a better understanding of the polar winter stratosphere and the critical problem of global ozone depletion.

  1. The Life Cycle of Stratospheric Aerosol Particles

    NASA Technical Reports Server (NTRS)

    Hamill, Patrick; Jensen, Eric J.; Russell, P. B.; Bauman, Jill J.

    1997-01-01

    This paper describes the life cycle of the background (nonvolcanic) stratospheric sulfate aerosol. The authors assume the particles are formed by homogeneous nucleation near the tropical tropopause and are carried aloft into the stratosphere. 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 stratosphere. The aerosol is removed from the stratosphere primarily at mid- and high latitudes through various processes, mainly by isentropic transport across the tropopause from the stratosphere into the troposphere.

  2. Injection of iodine to the stratosphere

    NASA Astrophysics Data System (ADS)

    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.

    2015-08-01

    We report a new estimation of the injection of iodine into the stratosphere 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 stratosphere 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 stratosphere and can exert a stratospheric 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 stratospheric ozone layer.

  3. Quantifying the Wave Driving of the Stratosphere

    NASA Technical Reports Server (NTRS)

    Newman, Paul A.; Nash, Eric R.

    1999-01-01

    The zonal mean eddy heat flux is directly proportional to the wave activity that propagates from the troposphere into the stratosphere. This quantity is a simple eddy diagnostic which is easily calculated from conventional meteorological analyses. Because this "wave driving" of the stratosphere has a strong impact on the stratospheric temperature, it is necessary to compare the impact of the flux with respect to stratospheric 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 stratospheric 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.

  4. The Evolution of Stratospheric Data Assimilation Systems

    NASA Technical Reports Server (NTRS)

    Rood, Richard B.; Einaudi, Franco (Technical Monitor)

    2001-01-01

    The use of model-assimilated meteorological observations for stratospheric research has become routine since the late 1980's. The first stratospheric 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 stratospheric 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 stratospheric 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 stratospheric reanalysis that covers the era of the Upper Atmosphere Research Satellite (UARS).

  5. Heterogeneous Chemistry Related to Stratospheric Aircraft

    NASA Technical Reports Server (NTRS)

    Tolbert, Margaret A.

    1995-01-01

    Emissions from stratospheric 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 stratosphere. Heterogeneous reactions on stratospheric 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 stratospheric 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 stratospheric aerosols.

  6. What Controls the Arctic Lower Stratosphere Temperature?

    NASA Technical Reports Server (NTRS)

    Newman, Paul A.; Nash, Eric R.; Einaudi, Franco (Technical Monitor)

    2001-01-01

    The temperature of the Arctic lower stratosphere is critical for understanding polar ozone levels. As temperatures drop below about 195 K, polar stratospheric clouds form, which then convert HCl and ClONO2 into reactive forms that are catalysts for ozone loss reactions. Hence, the lower stratospheric 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 stratosphere 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 stratosphere.

  7. Warm Up with Skill.

    ERIC Educational Resources Information Center

    Hoyle, R. J.; Smith, Robert F.

    1989-01-01

    Too little time is often spent on warm-up activities in the school or recreation class. Warm-ups are often perfunctory and unimaginative. Several suggestions are made for warm-up activities that incorporate both previously learned and new skills, while preparing the body for more vigorous activity. (IAH)

  8. The Cl-36 in the stratosphere

    NASA Technical Reports Server (NTRS)

    Deck, Bruce; Wahlen, Martin; Weyer, Harley; Kubik, Peter; Sharma, Pankaj; Gove, Harry

    1991-01-01

    Initial measurements of the cosmogenic radionuclide, Cl-36, in the lower stratosphere 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 stratosphere. Chlorine (Cl) and Cl compounds are important trace constituents for stratospheric chemistry, in particular with respect to O3 destruction. Stratospheric 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 stratosphere, 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 stratosphere by now, and measurements in the stratosphere to obtain cosmogenic production rates and concentration distributions is now possible. The use of cosmogenic Cl-36 as a tracer for stratospheric Cl chemistry and for stratospheric/tropospheric exchange processes is investigated. A first attempt to determine stratospheric 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.

  9. The influence of volcanic stratospheric aerosols on interannual global climate variations. Ph.D. Thesis

    SciTech Connect

    Andsager, K.M.

    1992-12-31

    A qualitative physical mechanism has been proposed to explain the forcing of the EI Nino/Southern Oscillation (ENSO) by low-latitude volcanic stratospheric aerosols. This mechanism is based on the normal global annual cycle resulting from the normal annual cycle in the distribution of incoming solar radiation. The presence of a volcanic stratospheric aerosol, which backscatters incoming solar radiation, is hypothesized to trigger the ENSO through an amplification of the normal annual decrease in wind strength and corresponding increase in sea surface temperatures (SST) in the eastern tropical Pacific Ocean. The observational evidence for an association between the record of volcanic eruptions and SST and the Southern Oscillation Index (SOI, Tahiti SLP minus Darwin SLP) over the last 120 years is examined using superposed epoch analysis. Composites using as key dates low-latitude volcanic eruptions suggest that these eruptions are followed by statistically significantly warm sea surface temperatures at least at the 1 percent level, if not higher, with the greatest warming generally occurring in the first three seasons after the eruption. Satellite data on the distribution of recent volcanic aerosols suggests that an aerosol must only be present over the tropics (about 20 deg S to 20 deg N) to trigger an ENSO event. For the physical mechanism by which an ENSO event may be triggered by a volcanic stratospheric aerosol, these results and the results of recent computer modeling studies imply the need for a shift away from past emphasis on surface cooling and SLP anomalies and toward consideration of stratospheric warming and changes in energy storage and transport.

  10. Is there a stratospheric fountain?

    NASA Astrophysics Data System (ADS)

    Pommereau, J.-P.; Held, G.

    2007-06-01

    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 stratosphere 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 stratosphere 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

  11. An intense stratospheric jet on Jupiter.

    PubMed

    Flasar, F M; Kunde, V G; Achterberg, R K; Conrath, B J; Simon-Miller, A A; Nixon, C A; Gierasch, P J; Romani, P N; Bézard, B; Irwin, P; Bjoraker, G L; Brasunas, J C; Jennings, D E; Pearl, J C; Smith, M D; Orton, G S; Spilker, L J; Carlson, R; Calcutt, S B; Read, P L; Taylor, F W; Parrish, P; Barucci, A; Courtin, R; Coustenis, A; Gautier, D; Lellouch, E; Marten, A; Prangé, R; Biraud, Y; Fouchet, T; Ferrari, C; Owen, T C; Abbas, M M; Samuelson, R E; Raulin, F; Ade, P; Césarsky, C J; Grossman, K U; Coradini, A

    2004-01-08

    The Earth's equatorial stratosphere shows oscillations in which the east-west winds reverse direction and the temperatures change cyclically with a period of about two years. This phenomenon, called the quasi-biennial oscillation, also affects the dynamics of the mid- and high-latitude stratosphere and weather in the lower atmosphere. Ground-based observations have suggested that similar temperature oscillations (with a 4-5-yr cycle) occur on Jupiter, but these data suffer from poor vertical resolution and Jupiter's stratospheric wind velocities have not yet been determined. Here we report maps of temperatures and winds with high spatial resolution, obtained from spacecraft measurements of infrared spectra of Jupiter's stratosphere. We find an intense, high-altitude equatorial jet with a speed of approximately 140 m s(-1), whose spatial structure resembles that of a quasi-quadrennial oscillation. Wave activity in the stratosphere also appears analogous to that occurring on Earth. A strong interaction between Jupiter and its plasma environment produces hot spots in its upper atmosphere and stratosphere near its poles, and the temperature maps define the penetration of the hot spots into the stratosphere.

  12. Extratropical Stratosphere-Troposphere Mass Exchange

    NASA Technical Reports Server (NTRS)

    Schoeberl, Mark R.

    2004-01-01

    Understanding the exchange of gases between the stratosphere and the troposphere is important for determining how pollutants enter the stratosphere and how they leave. This study does a global analysis of that the exchange of mass between the stratosphere 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 stratosphere 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 stratosphere through the tropics. But this study shows that almost 5 times more mass enters the stratosphere through the extra-tropics. This mass, however, is quickly recycled out again. Thus the lower most stratosphere is a mixture of upper stratospheric air and tropospheric air. This is an important result for understanding the chemistry of the lower stratosphere.

  13. The ISA-MIP Historical Eruption SO2 Emissions Assessment (HErSEA): an intercomparison for interactive stratospheric aerosol models

    NASA Astrophysics Data System (ADS)

    Mann, Graham; Dhomse, Sandip; Sheng, Jianxiong; Mills, Mike

    2016-04-01

    Major historical volcanic eruptions have injected huge amounts of sulphur dioxide into the stratosphere with observations showing an enhancement of the stratospheric aerosol layer for several years (ASAP, 2006). Such long-lasting increases in stratospheric aerosol loading cool the Earth's surface by scattering incoming solar radiation and warm the stratosphere 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 stratospheric 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 stratospheric aerosol models within the framework of the SPARC initiative on Stratospheric 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 stratosphere 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 stratospheric aerosol properties and simulated radiative forcings in different composition-climate models with interactive stratospheric 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 stratospheric 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

  14. Gravitational Separation in the Stratosphere - A New Tracer of Atmospheric Circulation

    NASA Astrophysics Data System (ADS)

    Ishidoya, S.; Sugawara, S.; Morimoto, S.; Aoki, S.; Nakazawa, T.; Honda, H.; Murayama, S.

    2012-12-01

    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 stratosphere; their observed vertical profiles are in good agreement with those expected theoretically from molecular mass differences. The O2/N2 ratio observed in the middle stratosphere, 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 stratosphere would be affected by an enhancement of the Brewer-Dobson circulation due to global warming. Therefore, the gravitational separation would be usable as a new tracer for an understanding of atmospheric circulation in the stratosphere.

  15. In-situ measurements of tropospheric and stratospheric ozone over Hyderabad

    NASA Astrophysics Data System (ADS)

    Manchanda, R. K.; Sreenivasan, S.; Sinha, P. R.

    The Study of the ozone concentration and its variability is one of the key indexes for environmental and ecological degradation While the stratospheric ozone absorbs the harmful ultraviolet radiation between 280-320 nm band, the tropospheric ozone is formed in the elevated layers up to 10km above ground level through the photochemical decomposition of the precursor gases like NOx, VOCs and non-methane hydrocarbons (NMHCs) released from the earth surface. Ozone studies are also vital for the understanding of solar terrestrial coupling as well as the ozone chemistry on a given site and its surroundings. Continuous measurements of vertical profile of ozone and various meteorological parameters (i.e. temperature, pressure, humidity, wind speed and direction) over one year period were made over Hyderabad using high altitude plastic balloons, in order to investigate i. variations of ozone in the troposphere and stratosphere, ii. stratospheric warming iii. coupling between upper troposphere and lower stratosphere (UTLS) region. Ozonesonde (Electro Chemical Cell) coupled with GPS RS80-15N radiosonde was used for the measurement of Ozone and meteorological parameters.

  16. Stratospheric Sulphur - 3D Chemical Transport Model Simulations and MIPAS/ENVISAT Satellite Measurements

    NASA Astrophysics Data System (ADS)

    Günther, Annika; Höpfner, Michael; Sinnhuber, Björn-Martin; Stiller, Gabriele; Clarmann, Thomas

    2016-04-01

    In this study processes that regulate the atmospheric distribution, and the budget of carbonyl sulphide (OCS), sulphur dioxide (SO2) and stratospheric sulphate aerosols are investigated in the upper troposphere / lower stratosphere. Sulphate aerosols impact the Earth's climate by backscattering parts of the incoming solar radiation. This negative radiative forcing can lead to reduced surface temperatures and is thought of as one reason for the recent global warming "hiatus". Our study is based on the comparison of modeled and observed data. An isentropic chemical transport model is used, spanning the region from 330 to 3000 K potential temperature (~ 8 - 66 km), driven by ERA-Interim Reanalysis data. The simulations are compared to observations from MIPAS (Michelson Interferometer for Passive Atmospheric Sounding), a limb sounder on the satellite ENVISAT that was operational from July 2002 to April 2012. The focus of our study lies on volcanically emitted SO2 and its dispersion, as main precursor for sulphate aerosol during volcanically perturbed times, with its simulated distribution and lifetime, in comparison to MIPAS SO2 measurements. Moreover data for OCS, as the main source for stratospheric sulphur during volcanically quiescent periods. Furthermore, first results of sulphuric aerosol-mass retrievals from MIPAS are presented. These will be combined with the gaseous sulphur species to obtain a global budget of stratospheric sulphur.

  17. Simulation of the climate effects of a geoengineered stratospheric sulfate cloud with the NASA GEOSCCM

    NASA Astrophysics Data System (ADS)

    Oman, L.; Aquila, V.; Colarco, P. R.

    2012-12-01

    Suggested solar radiation management (SRM) methods to mitigate global warming include the injection of sulfur dioxide (SO2 ) in the stratosphere. 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 stratosphere to a stratospheric SO2 injection. In particular, we investigate the changes of the stratospheric 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.

  18. THERMAL AND CHEMICAL STRUCTURE VARIATIONS IN TITAN'S STRATOSPHERE DURING THE CASSINI MISSION

    SciTech Connect

    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.

    2012-12-01

    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 stratosphere. 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 stratosphere during the Cassini mission, before and after the Northern Spring Equinox (NSE). We find indication for a weakening of the temperature gradient with warming of the stratosphere 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 stratosphere 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.

  19. The role of methane in projections of 21st century stratospheric water vapour

    NASA Astrophysics Data System (ADS)

    Revell, Laura E.; Stenke, Andrea; Rozanov, Eugene; Ball, William; Lossow, Stefan; Peter, Thomas

    2016-10-01

    Stratospheric water vapour (SWV) is an important component of the Earth's atmosphere as it affects both radiative balance and the chemistry of the atmosphere. Key processes driving changes in SWV include dehydration of air masses transiting the cold-point tropopause (CPT) and methane oxidation. We use a chemistry-climate model to simulate changes in SWV through the 21st century following the four canonical representative concentration pathways (RCPs). Furthermore, we quantify the contribution that methane oxidation makes to SWV following each of the RCPs. Although the methane contribution to SWV maximizes in the upper stratosphere, modelled SWV trends are found to be driven predominantly by warming of the CPT rather than by increasing methane oxidation. SWV changes by -5 to 60 % (depending on the location in the atmosphere and emissions scenario) and increases in the lower stratosphere in all RCPs through the 21st century. Because the lower stratosphere is where water vapour radiative forcing maximizes, SWV's influence on surface climate is also expected to increase through the 21st century.

  20. Laboratory Investigations of Stratospheric Halogen Chemistry

    NASA Technical Reports Server (NTRS)

    Wine, Paul H.; Nicovich, J. Michael; Stickel, Robert E.; Hynes, Anthony J.

    1997-01-01

    A final report for the NASA-supported project on laboratory investigations of stratospheric 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 stratospheric interest; and (3) photochemistry studies of interest for understanding stratospheric 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.

  1. Chlorine isotope fractionation in the stratosphere.

    PubMed

    Laube, J C; Kaiser, J; Sturges, W T; Bönisch, H; Engel, A

    2010-09-03

    Chlorinated organic compounds are important contributors to the anthropogenic enhancement of stratospheric ozone depletion. We report measurements of stratospheric isotope fractionation in such a compound. Stratospheric and tropospheric difluorodichloromethane (CF2Cl2) were found to have the largest relative 37Cl/35Cl isotope ratio difference ever measured for a natural compound. The increase of the relative isotope ratio difference with altitude was tightly correlated to the corresponding decrease in the CF2Cl2 mixing ratio. The observed relationship has a high potential to provide new insights into atmospheric chemistry and transport processes.

  2. Why Does the Stratosphere Get Moister During the 21st Century?

    NASA Technical Reports Server (NTRS)

    Dessler, A.E.; Schoberl, M. R.; Ye, H.; Wang, T.; Oman, L.; Douglass, A. R.

    2014-01-01

    All chemistry-climate models predict that 1) the TTL warms during the 21st century and 2) that the humidity of air entering the stratosphere 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 warming of the TTL explains only a fraction of the increase in humidity of air entering the stratosphere. 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 stratosphere in this model.

  3. Stratospheric ozone changes under solar geoengineering: implications for UV exposure and air quality

    NASA Astrophysics Data System (ADS)

    Nowack, Peer Johannes; Abraham, Nathan Luke; Braesicke, Peter; Pyle, John Adrian

    2016-03-01

    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 warming 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 warming, it leads to important changes in atmospheric composition. We find large stratospheric ozone increases that induce significant reductions in surface UV-B irradiance, which would have implications for vitamin D production. In addition, the higher stratospheric 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 stratospheric 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.

  4. Observed stratospheric profiles and stratospheric lifetimes of HCFC-141b and HCFC-142b

    SciTech Connect

    Lee, J.M.; Sturges, W.T.; Penkett, S.A.

    1995-06-01

    The authors present profile measurements of HCFC-141b and HCFC-142b in the stratosphere. The measurements show that these chemicals are not in equilibrium in the stratosphere at present, and allow inferences of stratospheric 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.

  5. Evidence for stratospheric hydrogen peroxide

    NASA Technical Reports Server (NTRS)

    Chance, K. V.; Traub, W. A.

    1987-01-01

    A statistically significant measurement of H2O2 in the stratosphere 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).

  6. Denitrification in the Antarctic stratosphere

    NASA Technical Reports Server (NTRS)

    Salawitch, R. J.; Gobbi, G. P.; Wofsy, S. C.; Mcelroy, M. B.

    1989-01-01

    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, stratospheric 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.

  7. Global warming mitigation by sulphur loading in the atmosphere: Required emissions and possible side effects

    NASA Astrophysics Data System (ADS)

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

    2009-04-01

    An approach to mitigate the global warming via sulphur loading in the stratosphere (geoengineering) is studied 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). 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 in the 21st century. Different ensemble members were constructed by varying emission intensity, residence time, optical properites, and horizontal distributions of stratospheric sulphates. In addition, starting and ending years of applied emissions are varied between different ensemble members. 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. Uniform latitudinal distribution of stratospheric sulphates is slightly less efficient. Sulphur emissions in the stratosphere required to stop the global temperature at the level corresponding to the mean value for 2000-2010 amount 5 - 10 TgS/yr in year 2050 and > 10 TgS/yr in year 2100. This is not a small part of the current emissions of tropospheric sulphates. Moreover, even if the global warming is stopped, temperature changes in different regions still occur with a magnitude up to 1 K. Their horizontal pattern depends on implied latitudinal distribution of stratospheric sulphates. If the geoengineering emissions are stopped, their climatic effect is removed within a few decades. In this period, surface air temperture may change with a rate of several Kelvins per decade. 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 the basis of the IAP RAS CM simulations.

  8. Stratospheric aftermath of the 2010 Storm on Saturn as observed by the TEXES instrument. I. Temperature structure

    NASA Astrophysics Data System (ADS)

    Fouchet, Thierry; Greathouse, Thomas K.; Spiga, Aymeric; Fletcher, Leigh N.; Guerlet, Sandrine; Leconte, Jérémy; Orton, Glenn S.

    2016-10-01

    We report on spectroscopic observations of Saturn's stratosphere in July 2011 with the Texas Echelon Cross Echelle Spectrograph (TEXES) mounted on the NASA InfraRed Telescope Facility (IRTF). The observations, targeting several lines of the CH4ν4 band and the H2 S(1) quadrupolar line, were designed to determine how Saturn's stratospheric thermal structure was disturbed by the 2010 Great White Spot. A study of Cassini Composite Infrared Spectrometer (CIRS) spectra had already shown the presence of a large stratospheric disturbance centered at a pressure of 2 hPa, nicknamed the beacon B0, and a tail of warm air at lower pressures (Fletcher et al. [2012] Icarus 221, 560-586). Our observations confirm that the beacon B0 vertical structure determined by CIRS, with a maximum temperature of 180 ± 1 K at 2 hPa, is overlain by a temperature decrease up to the 0.2-hPa pressure level. Our retrieved maximum temperature of 180 ± 1 K is colder than that derived by CIRS (200 ± 1 K), a difference that may be quantitatively explained by terrestrial atmospheric smearing. We propose a scenario for the formation of the beacon based on the saturation of gravity waves emitted by the GWS. Our observations also reveal that the tail is a planet-encircling disturbance in Saturn's upper stratosphere, oscillating between 0.2 and 0.02 hPa, showing a distinct wavenumber-2 pattern. We propose that this pattern in the upper stratosphere is either the signature of thermal tides generated by the presence of the warm beacon in the mid-stratosphere, or the signature of Rossby wave activity.

  9. Pronounced Minima in Tropospheric Ozone and OH above the Tropical West Pacific and their Role for Stratospheric Composition

    NASA Astrophysics Data System (ADS)

    Rex, M.; Wohltmann, I.; Lehmann, R.; Rosenlof, K. H.; Wennberg, P. O.; Weisenstein, D. K.; Notholt, J.; Krüger, K.; Mohr, V.; Tegtmeier, S.

    2014-12-01

    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 stratosphere. Hence, the omnipresent layer of OH in the troposphere shields the stratosphere 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 warm pool is key for troposphere to stratosphere exchange. We report measurements of 14 ozonesondes launched during the Transbrom ship cruise through the center of the warm 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 stratospheric composition. Specifically, we discuss the role of emissions of biogenic halogenated species from this geographic region for stratospheric 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 stratospheric aerosol budget.

  10. Laboratory studies of stratospheric aerosol chemistry

    NASA Technical Reports Server (NTRS)

    Molina, Mario J.

    1996-01-01

    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 stratospheric aerosols, and measurements of reaction probabilities directly on ice aerosols with sizes corresponding to those of polar stratospheric cloud particles. The results of these investigations are of importance for the assessment of the potential stratospheric 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 stratospheric clouds and on the chemistry induced by these clouds.

  11. Planetary science: Music of the stratospheres

    NASA Astrophysics Data System (ADS)

    Dowling, Timothy E.

    2008-05-01

    Fifteen-year oscillations in Saturn's equatorial stratosphere 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.

  12. The chemistry of stratospheric ozone depletion

    SciTech Connect

    Tuck, A.

    1997-01-01

    In the early 1980`s the Antarctic ozone hole was discovered. The ozone loss was 50 percent in the lower stratosphere during springtime, which is made possible by the conditions over Antarctica in winter. The absence of sunlight in the stratosphere during polar winter causes the stratospheric air column there to cool and sink, drawing air from lower latitudes into the upper stratosphere. 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.

  13. SOFIA - Stratospheric Observatory for Infrared Astronomy

    NASA Technical Reports Server (NTRS)

    Kunz, Nans; Bowers, Al

    2007-01-01

    This viewgraph presentation reviews the Stratospheric 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.

  14. SOFIA: Stratospheric Observatory for Infrared Astronomy

    NASA Technical Reports Server (NTRS)

    Becker, Eric; Kunz, Nans; Bowers, Al

    2007-01-01

    This viewgraph presentation reviews the Stratospheric 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.

  15. Nitrogen-sulfur compounds in stratospheric aerosols

    NASA Technical Reports Server (NTRS)

    Farlow, N. H.; Snetsinger, K. G.; Hayes, D. M.; Lem, H. Y.; Tooper, B. M.

    1978-01-01

    Two forms of nitrosyl sulfuric acid (NOHSO4 and NOHS2O7) have been tentatively identified in stratospheric 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 stratospheric aerosols could vary from one-third to twice the amount of NO in the surrounding air. If these reactions occur in the stratosphere, 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 stratosphere of excessive pollutants.

  16. A Strange Thing Happened in the Stratosphere

    NASA Video Gallery

    What would cause a wind pattern that held for at least 60 years to suddenly change? NASA scientists are working to understand the recent quirky behavior of winds in Earth’s stratosphere.Credit: N...

  17. Stratospheric Relaxation in IMPACT's Radiation Code

    SciTech Connect

    Edis, T; Grant, K; Cameron-Smith, P

    2006-11-13

    While Impact incorporates diagnostic radiation routines from our work in previous years, it has not previously included the stratospheric relaxation required for forcing calculations. We have now implemented the necessary changes for stratospheric relaxation, tested its stability, and compared the results with stratosphere temperatures obtained from CAM3 met data. The relaxation results in stable temperature profiles in the stratosphere, 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.

  18. Stratospheric sounding by infrared heterodyne spectroscopy

    NASA Technical Reports Server (NTRS)

    Abbas, M. M.; Kunde, V. G.; Mumma, M. J.; Kostiuk, T.; Buhl, D.; Frerking, M. A.

    1978-01-01

    Intensity profiles of infrared spectral lines of stratospheric constituents can be fully resolved with a heterodyne spectrometer of sufficiently high resolution. 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 stratospheric constituents, indicating a large number of minor constituents which can be studied. Stratospheric spectral line shapes, and the resolution required to measure them are discussed in light of calculated synthetic line profiles for some stratospheric 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.

  19. Trajectory tracking control for underactuated stratospheric airship

    NASA Astrophysics Data System (ADS)

    Zheng, Zewei; Huo, Wei; Wu, Zhe

    2012-10-01

    Stratospheric 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 stratospheric airship is presented in this paper. Firstly, the TLC theory is described sketchily, and the dynamic model of the stratospheric 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 stratospheric airship to track typical trajectories are illustrated to verify effectiveness of the proposed approach.

  20. What Controls the Arctic Lower Stratosphere Temperature?

    NASA Technical Reports Server (NTRS)

    Newman, Paul A.; Nash, Eric R.; Einaudi, Franco (Technical Monitor)

    2000-01-01

    The temperature of the Arctic lower stratosphere is critical for understanding polar ozone levels. As temperatures drop below about 195 K, polar stratospheric clouds form, which then convert HCl and ClONO2 into reactive forms that are catalysts for ozone loss reactions. Hence, the lower stratospheric 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 stratosphere during the January through February period.

  1. Polar stratospheric clouds inferred from satellite data

    NASA Astrophysics Data System (ADS)

    Austin, J.; Jones, R. L.; Remsberg, E. E.; Tuck, A. F.

    1986-11-01

    Anomalously high radiances from the ozone channel of the Limb Infrared Monitor of the Stratosphere (LIMS) sounding instrument have been observed in the Northern Hemisphere winter lower stratosphere. Such events, thought to be due to polar stratospheric clouds (PSCs), are examined further by computing relative humidities using Stratospheric 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.

  2. The stratcom 8 effort. [stratospheric photochemistry

    NASA Technical Reports Server (NTRS)

    Reed, E. I. (Editor)

    1980-01-01

    The ozone-nitrogen oxides ultraviolent flux interactions were investigated to obtain data on stratospheric photochemistry. The balloon, rocket, and aircraft operations are described along with the instruments, parameter measurements, and payloads.

  3. Lidar backscattering measurements of background stratospheric aerosols

    NASA Technical Reports Server (NTRS)

    Remsberg, E. E.; Northam, G. B.; Butler, C. F.

    1979-01-01

    A comparative lidar-dustsonde experiment was conducted in San Angelo, Texas, in May 1974 in order to estimate the uncertainties in stratospheric-aerosol backscatter for the NASA Langley 48-inch lidar system. The lidar calibration and data-analysis procedures are discussed. Results from the Texas experiment indicate random and systematic uncertainties of 35 and 63 percent, respectively, in backscatter from a background stratospheric-aerosol layer at 20 km.

  4. Spectroscopic detection of stratospheric hydrogen cyanide

    NASA Technical Reports Server (NTRS)

    Coffey, M. T.; Mankin, W. G.; Cicerone, R. J.

    1981-01-01

    A number of features have been identified as absorption lines of hydrogen cyanide in infrared spectra of stratospheric absorption obtained from a high-altitude aircraft. Column amounts of stratospheric 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.

  5. Transport of ozone in the middle stratosphere - Evidence for planetary wave breaking

    NASA Astrophysics Data System (ADS)

    Leovy, C. B.; Sun, C.-R.; Hitchman, M. H.; Remsberg, E. E.; Russell, J. M., III; Gordley, L. L.; Gille, J. C.; Lyjak, L. V.

    1985-02-01

    Data from the Nimbus 7 Limb Infrared Monitor of the Stratosphere (LIMS) for the period October 25, 1978-May 28, 1979 are used in a descriptive study of ozone variations in the middle stratosphere. It is shown that the ozone distribution is strongly influenced by irreversible deformation associated with large amplitude planetary-scale waves. This process, which has been described by McIntyre and Palmer as planetary wave breaking, takes place throughout the 3-30 mb layer, and poleward transport of ozone within this layer occurs in narrow tongues drawn on the tropics and subtropics in association with major and minor warming events. These events complement the zonal mean diabatic circulation in producing significant changes in the total column amount of ozone.

  6. Injection of iodine to the stratosphere

    NASA Astrophysics Data System (ADS)

    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

    2016-04-01

    There are still many uncertainties about the influence of iodine chemistry in the stratosphere, 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 stratosphere 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 stratosphere 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 stratosphere and can exert a stratospheric 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 stratospheric ozone layer.

  7. Stratospheric Transport Times From Observations and Models

    NASA Astrophysics Data System (ADS)

    Hoor, P. M.; Lelieveld, J.; Boenisch, H.; Joeckel, P.; Steil, B.; Bruehl, C.; Strahan, S.

    2007-12-01

    Transport time scales in the stratosphere are crucial to understand and calculate the effects of chemical active species on stratospheric chemistry. In general CO2 or SF6 have been used to calculate mean ages of air in the stratosphere, whereas shorter lived trace gases like CO are used to investigate cross tropopause transport and mixing on short time-scales close to the tropopause. Besides mean ages and their assocated mean trace gas mixing ratios at a given point in the atmosphere other quantities of the trace gas distributions can be used to constrain stratospheric transport times, such as variability and slope. In particular the younger part of the age spectrum needs to be constrained since it determines the extent to which shorter lived compounds can be transported into the stratosphere. We investigate transport times in the stratosphere based on observations of CO, N2O and CO2 and test a new approach to deduce transport times. For that purpose we compare observations from the ER-2 and other platforms. The approach is applied to global models (ECHAM5/MESSy, Combo GMI) to identify barriers as well as regions of rapid mixing and transport.

  8. Seasonal Stratospheric Chemistry on Uranus and Neptune

    NASA Astrophysics Data System (ADS)

    Moses, Julianne I.; Greathouse, Thomas K.; Orton, Glenn S.; Hue, Vincent; Poppe, Andrew R.; Luszcz-Cook, Statia H.; Moullet, Arielle

    2016-10-01

    We use a time-variable photochemical model to study the change in stratospheric constituent abundances as a function of altitude, latitude, and season on Uranus and Neptune. In the absence of meridional transport, the results for Neptune are similar to those predicted for Saturn: seasonal variations in the abundances of observable hydrocarbons such as C2H2, C2H4, C2H6, C3H4, C3H8, and C4H2 are large in the upper stratosphere but become increasingly damped with depth due to increased dynamical and chemical time scales. We also find that latitude gradients in hydrocarbon abundances would be maintained on Neptune in the absence of atmospheric circulation. On Uranus, however, the more stagnant, poorly mixed stratosphere leads to a lower-altitude homopause, with methane being photolyzed relatively deep in the stratosphere, at which point both diffusion and chemical time constants have become longer than a Uranian year. Seasonal variations in stratospheric constituents on Uranus are therefore muted, despite the planet's large obliquity. We compare our model results to global-average observations from Spitzer and to spatially-resolved infrared observations from the ground. The model-data comparisons have implications with respect to the importance and strength of meridional transport, the origin of stratospheric oxygen-bearing species, and the dust and cometary influx rates on Uranus and Neptune.

  9. Climatology of the stratospheric polar vortex and planetary wave breaking

    NASA Technical Reports Server (NTRS)

    Baldwin, Mark P.; Holton, James R.

    1988-01-01

    The distribution of Ertel's potential vorticity (PV) on the 850 K isentropic surface is used to establish a climatology for the transient evolution of the planetary scale circulation in the Northern Hemisphere winter midstratosphere. PV distributions are computed from gridded NMC daily temperature and height maps for the 10 and 30 mb levels, and show that a very good approximation for 850 K PV can be derived from 10 mb heights and temperatures alone. It is assumed that reversals of the latitudinal gradient of PV, localized in longitude and latitude may be regarded as signatures of planetary wave breaking. Wave breaking identified by such signatures tends to occur mainly in the vicinity of the Aleutian anticyclone, with a secondary maximum over Europe. The area of the polar vortex, defined as the area enclosed by PV contours greater than a certain critical value, is strongly influenced by wave breaking. Erosion of the polar vortex due to transport and mixing of PV leads to a preconditioned state, when defined in terms of vortex area, that always occurs prior to major stratospheric warmings. During winters with little PV transport or mixing, the vortex area evolves rather uniformly in response to radiative forcing. During winters with major sudden warmings, the wave breaking signature as defined here first appears at low values of PV, then rapidly moves toward higher values as the vortex area is reduced and the 'surf-zone' structure becomes well defined.

  10. Extreme climate of the global troposphere and stratosphere in 1940-42 related to El Niño.

    PubMed

    Brönnimann, S; Luterbacher, J; Staehelin, J; Svendby, T M; Hansen, G; Svenøe, T

    2004-10-21

    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 stratosphere are controversial. Using historical observations and reconstruction techniques, we analyse the anomalous state of the troposphere and stratosphere 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 stratosphere, 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 stratospheric warmings 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-stratosphere system in northern winter that is related to strong El Niño events.

  11. The climatic effects of the direct injection of water vapour into the stratosphere by large volcanic eruptions

    NASA Astrophysics Data System (ADS)

    Joshi, M. M.; Jones, G. S.

    2009-08-01

    We describe a novel mechanism that can significantly lower the amplitude of the climatic response to certain large volcanic eruptions and examine its impact with a coupled ocean-atmosphere climate model. If sufficiently large amounts of water vapour enter the stratosphere, a climatically significant amount of water vapour can be left over in the lower stratosphere after the eruption, even after sulphate aerosol formation. This excess stratospheric humidity warms the tropospheric climate, and acts to balance the climatic cooling induced by the volcanic aerosol, especially because the humidity anomaly lasts for a period that is longer than the residence time of aerosol in the stratosphere. In particular, northern hemisphere high latitude cooling is reduced in magnitude. We discuss this mechanism in the context of the discrepancy between the observed and modelled cooling following the Krakatau eruption in 1883. We hypothesize that moist coignimbrite plumes caused by pyroclastic flows travelling over ocean rather than land, resulting from an eruption close enough to the ocean, might provide the additional source of stratospheric water vapour.

  12. An Estimation of the Climatic Effects of Stratospheric Ozone Losses during the 1980s. Appendix K

    NASA Technical Reports Server (NTRS)

    MacKay, Robert M.; Ko, Malcolm K. W.; Shia, Run-Lie; Yang, Yajaing; Zhou, Shuntai; Molnar, Gyula

    1997-01-01

    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 stratospheric 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 stratospheric ozone are included, the greenhouse warming 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 stratosphere are very important in determining the steady-state response to high latitude ozone losses. The 39% compensation in greenhouse warming resulting from lower stratospheric 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.

  13. Issues in Stratospheric Ozone Depletion.

    NASA Astrophysics Data System (ADS)

    Lloyd, Steven Andrew

    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 stratosphere. 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 stratospheric 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

  14. Warm-Up Activities.

    ERIC Educational Resources Information Center

    Mingguang, Yang

    1999-01-01

    Discusses how warm-up activities can help to make the English-as-a-foreign-language classroom a lively and interesting place. Warm-up activities are games carried out at the beginning of each class to motivate students to make good use of class time. (Author/VWL)

  15. Global Warming Trends.

    ERIC Educational Resources Information Center

    Jones, Philip D.; Wigley, Tom M. L.

    1990-01-01

    Results from the analysis of land and marine records from the past century are presented. It is indicated that the planet earth has warmed about one-half of a degree celsius. The uncertainty of these measurements and future warming trends are discussed. (CW)

  16. Isolating the roles of different forcing agents in global stratospheric temperature changes using model integrations with incrementally added single forcings

    NASA Astrophysics Data System (ADS)

    Aquila, V.; Swartz, W. H.; Waugh, D. W.; Colarco, P. R.; Pawson, S.; Polvani, L. M.; Stolarski, R. S.

    2016-07-01

    Satellite instruments show a cooling of global stratospheric 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 stratospheric 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 stratosphere from 1979 to present is mostly driven by changes in GHG concentrations in the middle and upper stratosphere and by GHG and ODS changes in the lower stratosphere. While the cooling trend caused by increasing GHGs is roughly constant over the satellite era, changing ODS concentrations cause a significant stratospheric 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 stratospheric 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 stratospheric temperatures: in the lower stratosphere, 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 warming and the volcanically induced ozone depletion. In the middle and upper stratosphere, changes in solar

  17. Observational constraints on the tropospheric and near-surface winter signature of the Northern Hemisphere stratospheric polar vortex

    NASA Astrophysics Data System (ADS)

    Graf, Hans-F.; Zanchettin, Davide; Timmreck, Claudia; Bittner, Matthias

    2014-12-01

    A composite analysis of Northern Hemisphere's mid-winter tropospheric anomalies under the conditions of strong and weak stratospheric polar vortex was performed on NCEP/NCAR reanalysis data from 1948 to 2013 considering, as additional grouping criteria, the coincidental states of major seasonally relevant climate phenomena, such as El Niño-Southern Oscillation (ENSO), Quasi Biennial Oscillation and strong volcanic eruptions. The analysis reveals that samples of strong polar vortex nearly exclusively occur during cold ENSO states, while a weak polar vortex is observed for both cold and warm ENSO. The strongest tropospheric and near-surface anomalies are found for warm ENSO and weak polar vortex conditions, suggesting that internal tropospheric circulation anomalies related to warm ENSO constructively superpose on dynamical effects from the stratosphere. Additionally, substantial differences are found between the continental winter warming patterns under strong polar vortex conditions in volcanically-disturbed and volcanically-undisturbed winters. However, the small-size samples obtained from the multi-compositing prevent conclusive statements about typical patterns, dominating effects and mechanisms of stratosphere-troposphere interaction on the seasonal time scale based on observational/reanalysis data alone. Hence, our analysis demonstrates that patterns derived from observational/reanalysis time series need to be taken with caution as they not always provide sufficiently robust constraints to the inferred mechanisms implicated with stratospheric polar vortex variability and its tropospheric and near-surface signature. Notwithstanding this argument, we propose a limited set of mechanisms that together may explain a relevant part of observed climate variability. These may serve to define future numerical model experiments minimizing the sample biases and, thus, improving process understanding.

  18. Microphysical and radiative changes in cirrus clouds by geoengineering the stratosphere

    NASA Astrophysics Data System (ADS)

    Cirisan, A.; Spichtinger, P.; Luo, B. P.; Weisenstein, D. K.; Wernli, H.; Lohmann, U.; Peter, T.

    2013-05-01

    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 warming. Here we investigate the impacts on northern midlatitude cirrus from continuous SO2emissions of 2-10 Mt/a in the tropical stratosphere. 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 stratospheric 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 stratospheric 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 stratospheric aerosols. This suggests that stratospheric 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.

  19. Oxygen Compounds in Saturn’s Stratosphere During the 2010 Northern Storm

    NASA Astrophysics Data System (ADS)

    Hesman, Brigette E.; Bjoraker, G. L.; Achterberg, R. K.; Jennings, D. E.; Romani, P. N.; Fletcher, L. N.; Irwin, P. G.

    2013-10-01

    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” (warm regions in the stratosphere 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). In order to build a comprehensive picture of the changes to the stratosphere due to the 2010 northern storm we are now investigating the oxygen compounds in Saturn’s stratosphere to determine if similar changes in these species were measured. The time evolution of stratospheric CO2 and H2O abundances in the beacon regions throughout 2011 and 2012 will be presented. References: Bjoraker, G., B.E. Hesman, R.K. Achterberg, P.N. Romani. 2012, “The Evolution of Hydrocarbons in Saturn’s Northern Storm Region,” AAS DPS Conference, Vol. 44, #403.05. Fletcher, L.N. et al. 2012, “The Origin and Evolution of Saturn’s 2011-2012 Stratospheric Vortex,” Icarus, 221, 560-586. Hesman, B.E. et al. 2012a, “Elusive Ethylene Detected in Saturn’s Northern Storm Region,” The Astrophysical Journal, 760, 24-30. Hesman, B.E. et al. 2012b, “Ethylene Emission in the Aftermath of Saturn’s 2010 Northern Storm,” AAS DPS Conference, Vol. 44, #403.06.

  20. The vertical and spatial structure of ENSO in the upper troposphere and lower stratosphere from GPS radio occultation measurements

    NASA Astrophysics Data System (ADS)

    Scherllin-Pirscher, B.; Deser, C.; Ho, S.-P.; Chou, C.; Randel, W.; Kuo, Y.-H.

    2012-10-01

    The vertical and spatial structure of the atmospheric El Niño-Southern Oscillation (ENSO) signal is investigated using radio occultation (RO) data from August 2006 to December 2010. Due to their high vertical resolution and global coverage, RO data are well suited to describe the full 3-dimensional ENSO structure in the troposphere and lower stratosphere. We find that interannual temperature anomalies in the equatorial region show a natural decomposition into zonal-mean and eddy (deviations from the zonal-mean) components that are both related to ENSO. Consistent with previous studies, we find that during the warm phase of ENSO, zonal-mean temperatures increase in the tropical troposphere and decrease in the tropical stratosphere. Maximum warming occurs above 8 km, and the transition between warming and cooling occurs near the tropopause. This zonal-mean response lags sea surface temperature anomalies in the eastern equatorial Pacific by 3 months. The atmospheric eddy component, in contrast, responds rapidly (within 1 month) to ENSO forcing. This signal features a low-latitude dipole between the Indian and Pacific Oceans, with off-equatorial maxima centered around 20° to 30° latitude in both hemispheres. The eddy response pattern attains maximum amplitude in the upper troposphere near 11 km and (with opposite polarity) in a shallow layer near the tropopause at approximately 17 km. The eddy ENSO signal tends to be out-of-phase between low and middle latitudes in both the troposphere and lower stratosphere.

  1. OCS, stratospheric aerosols and climate

    NASA Astrophysics Data System (ADS)

    Turco, R. P.; Whitten, R. C.; Toon, O. B.; Pollack, J. B.; Hamill, P.

    1980-01-01

    Carbonyl sulphide (OCS) is found to be the predominant sulphur-bearing compound in our atmosphere1-3. It contributes to the formation of stratospheric sulphate aerosol particles4, which affect the Earth's radiation balance and climate5-7. Using recently obtained data, we estimate that OCS has a global source of ~5 tg per year (tg = 1012 g) and a lifetime of roughly 1 yr. We calculate that increasing anthropogenic emissions of OCS could cause measurable climate alterations within the next century. Numerous sources of OCS have been identified (see Fig. 1). Crutzen et al.8 estimate that natural and agricultural fires contribute 0.2-0.3 tg of OCS to the atmosphere each year. Adams et al.9 measured average OCS emission rates for a variety of common soils of about 0.004 g m-2 yr-1, which may be extrapolated to a global OCS source of nearly 0.5 tg yr-1. Adams et al.9 also noted OCS emissions several thousand times greater than average above saline marshes. Carbonyl sulphide has been detected near cattle feedlots in concentrations as high as 6,000 p.p.b.v.10. Volcanoes and fumaroles seem to represent a minor source of OCS (refs 11,12). We estimate that the direct contributions of biospheric processes to the OCS budget may be ~1 tg yr-1.

  2. Trends in stratospheric minor constituents

    NASA Technical Reports Server (NTRS)

    Stolarski, R. S.; Chu, W. P.; Coffey, M. T.; Heaps, W. S.; Kaye, J. A.; Mccormick, M. P.; Zander, R.

    1989-01-01

    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 stratospheric 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.

  3. The impact of polar stratospheric ozone loss on Southern Hemisphere stratospheric circulation and climate

    NASA Astrophysics Data System (ADS)

    Keeble, J.; Braesicke, P.; Abraham, N. L.; Roscoe, H. K.; Pyle, J. A.

    2014-12-01

    The impact of polar stratospheric ozone loss resulting from chlorine activation on polar stratospheric 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 stratospheric temperatures and an increase of > 6 K in the upper stratosphere. 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 stratosphere and increased dynamical heating in the upper stratosphere. The cooling of the polar lower stratosphere leads, through thermal wind balance, to an acceleration of the polar vortex and delays its breakdown by ~ 2 weeks. A link between lower stratospheric zonal wind speed, the vertical component of the Eliassen-Palm (EP) flux, Fz and the residual mean vertical circulation, 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 stratosphere 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 stratospheric signals modelled in this study propagate down to the troposphere, and lead to significant surface changes in December.

  4. Curing of epoxy matrix composite in stratosphere

    NASA Astrophysics Data System (ADS)

    Kondyurin, Alexey; Kondyurina, Irina; Bilek, Marcela

    Large structures for habitats, greenhouses, space bases, space factories are needed for next stage of space exploitation. A new approach enabling large-size constructions in space relies on the use of the polymerization technology of fiber-filled composites with a curable polymer matrix applied in the free space environment. The polymerisation process is proposed for the material exposed to high vacuum, dramatic temperature changes, space plasma, sun irradiation and atomic oxygen (in low Earth orbit), micrometeorite fluence, electric charging and microgravitation. The stratospheric flight experiments are directed to an investigation of the curing polymer matrix under the stratospheric conditions on. The unique combination of low atmospheric pressure, high intensity UV radiation including short wavelength UV and diurnal temperature variations associated with solar irradiation strongly influences the chemical processes in polymeric materials. The first flight experiment with uncured composites was a part of the NASA scientific balloon flight program realised at the NASA stratospheric balloon station in Alice Springs, Australia. A flight cassette installed on payload was lifted with a “zero-pressure” stratospheric balloon filled with Helium. Columbia Scientific Balloon Facility (CSBF) provided the launch, flight telemetry and landing of the balloon and payload. A cassette of uncured composite materials with an epoxy resin matrix was exposed 3 days in the stratosphere (40 km altitude). The second flight experiment was realised in South Australia in 2012, when the cassette was exposed in 27 km altitude. An analysis of the chemical structure of the composites showed, that the space irradiations are responsible for crosslinking of the uncured polymers exposed in the stratosphere. The first prepreg in the world was cured successfully in stratosphere. The investigations were supported by Alexander von Humboldt Foundation, NASA and RFBR (12-08-00970) grants.

  5. An exploration of Saturn's stratospheric dynamics through Global Climate Modeling

    NASA Astrophysics Data System (ADS)

    Spiga, Aymeric; Guerlet, Sandrine; Indurain, Mikel; Millour, Ehouarn; Sylvestre, Mélody; Thierry, Fouchet; Meurdesoif, Yann; Thomas, Dubos

    2014-11-01

    A decade of Cassini observations has yielded a new vision on the dynamical phenomena in Saturn's troposphere and stratosphere. 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 warming 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 stratospheric 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

  6. Warm autoimmune hemolytic anemia.

    PubMed

    Naik, Rakhi

    2015-06-01

    Warm autoimmune hemolytic anemia (AIHA) is defined as the destruction of circulating red blood cells (RBCs) in the setting of anti-RBC autoantibodies that optimally react at 37°C. The pathophysiology of disease involves phagocytosis of autoantibody-coated RBCs in the spleen and complement-mediated hemolysis. Thus far, treatment is aimed at decreasing autoantibody production with immunosuppression or reducing phagocytosis of affected cells in the spleen. The role of complement inhibitors in warm AIHA has not been explored. This article addresses the diagnosis, etiology, and treatment of warm AIHA and highlights the role of complement in disease pathology.

  7. Bismuth Oxide Nanoparticles in the Stratosphere

    NASA Technical Reports Server (NTRS)

    Rietmeijer, Frans J. M.; Mackinnon, Ian D. R.

    1997-01-01

    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 stratosphere at 17-19 km altitude. Similar Bi oxide nanograins were present in the upper stratosphere during May 1985. These grains are linked to the plumes of several major volcanic eruptions during the early 1980s that injected material into the stratosphere. The mass of sulfur from these eruptions is a proxy for the mass of stratospheric 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 stratosphere.

  8. The atmospheric effects of stratospheric aircraft

    NASA Technical Reports Server (NTRS)

    Stolarski, Richard S. (Editor); Wesoky, Howard L. (Editor)

    1993-01-01

    This document presents a second report from the Atmospheric Effects of Stratospheric Aircraft (AESA) component of NASA's High-Speed Research Program (HSRP). This document presents a second report from the Atmospheric Effects of Stratospheric 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 stratospheric 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 stratospheric 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 stratosphere. The assessment of fleet effects is dependent on the ability to develop scenarios which correctly simulate fleet operations.

  9. Evolution of potential vorticity in the winter stratosphere of January-February 1979

    NASA Astrophysics Data System (ADS)

    Dunkerton, Timothy J.; Delisi, Donald P.

    Nimbus 7 Limb Infrared Monitor of the Stratosphere (LIMS) observations are used to study the evolution of potential vorticity in the stratosphere, January-February 1979. Daily analysis of this quantity at 850° and 1200°K provides circumstantial evidence of planetary wave ``breaking'' by which air parcels undergo rapid and irreversible separation from the circumpolar vortex during stratospheric warnings. Complementing this effect is the advection of subtropical, low-vorticity air into the polar region. Temporal evolution of the size, shape, and orientation of the main circumpolar vortex is revealed very clearly by the potential vorticity field. All three factors are important, although some have been emphasized more strongly in previous literature. The size of the vortex determines the range of latitudes over which planetary Rossby waves are able to propagate vertically. Diminution of vortex area during the observed warmings is believed to precondition the flow, focusing subsequent Rossby wave activity into the polar cap, as in the major warming of late February 1979. The shape of the vortex undergoes both reversible and irreversible deformation. Examples of irreversible deformation are seen in the advective formation of extended high-vorticity tongues over subtropical latitudes in connection with the warnings of late January, early February, and late February 1979. Two of these were recently discussed by McIntyre and Palmer. Reversible deformation is observed in the sudden cooling and concurrent wave 1, wave 2 vacillation, after the January warming. The orientation of the vortex can also be important, as in the period of rotation leading up to the major wave 2 warming of late February 1979. We suggest that the orientation of the vortex be included as part of the preconditioning process, in accord with numerical results of Butchart et al. We briefly consider the vertical structure of potential vorticity and ozone on two disturbed days in late January 1979

  10. Climate model simulation of winter warming and summer cooling following the 1991 Mount Pinatubo volcanic eruption

    NASA Astrophysics Data System (ADS)

    Kirchner, Ingo; Stenchikov, Georgiy L.; Graf, Hans-F.; Robock, Alan; AntuñA, Juan Carlos

    1999-08-01

    We simulate climate change for the 2-year period following the eruption of Mount Pinatubo in the Philippines on June 15, 1991, with the ECHAM4 general circulation model (GCM). The model was forced by realistic aerosol spatial-time distributions and spectral radiative characteristics calculated using Stratospheric Aerosol and Gas Experiment II extinctions and Upper Atmosphere Research Satellite-retrieved effective radii. We calculate statistical ensembles of GCM simulations with and without volcanic aerosols for 2 years after the eruption for three different sea surface temperatures (SSTs): climatological SST, El Niño-type SST of 1991-1993, and La Niña-type SST of 1984-1986. We performed detailed comparisons of calculated fields with observations. We analyzed the atmospheric response to Pinatubo radiative forcing and the ability of the GCM to reproduce it with different SSTs. The temperature of the tropical lower stratosphere increased by 4 K because of aerosol absorption of terrestrial longwave and solar near-infrared radiation. The heating is larger than observed, but that is because in this simulation we did not account for quasi-biennial oscillation (QBO) cooling and the cooling effects of volcanically induced ozone depletion. We estimated that both QBO and ozone depletion decrease the stratospheric temperature by about 2 K. The remaining 2 K stratospheric warming is in good agreement with observations. By comparing the runs with the Pinatubo aerosol forcing with those with no aerosols, we find that the model calculates a general cooling of the global troposphere, but with a clear winter warming pattern of surface air temperature over Northern Hemisphere continents. This pattern is consistent with the observed temperature patterns. The stratospheric heating and tropospheric summer cooling are directly caused by aerosol radiative effects, but the winter warming is indirect, produced by dynamical responses to the enhanced stratospheric latitudinal temperature

  11. Evidence for an earlier greenhouse cooling effect in the stratosphere before the 1980s over the Northern Hemisphere

    NASA Astrophysics Data System (ADS)

    Zerefos, C. S.; Tourpali, K.; Zanis, P.; Eleftheratos, K.; Repapis, C.; Goodman, A.; Wuebbles, D.; Isaksen, I. S. A.; Luterbacher, J.

    2014-01-01

    This study provides a new look at the observed and calculated long-term temperature changes since 1958 for the region extending from the lower troposphere up to the lower stratosphere of the Northern Hemisphere. The analysis is mainly based on monthly layer mean temperatures derived from geopotential height thicknesses between specific pressure levels. Layer mean temperatures from thickness improve homogeneity in both space and time and reduce uncertainties in the trend analysis. Datasets used include the NCEP/NCAR I reanalysis, the Free University of Berlin (FU-Berlin) and the RICH radiosonde datasets as well as historical simulations with the CESM1-WACCM global model participating in CMIP5. After removing the natural variability with an autoregressive multiple regression model our analysis shows that the time interval of our study 1958-2011 can be divided in two distinct sub-periods of long term temperature variability and trends; before and after 1980s. By calculating trends for the summer time to reduce interannual variability, the two periods are as follows. From 1958 until 1979, non-significant trends or slight cooling trends prevail in the lower troposphere (0.06 ± 0.06 °C decade-1 for NCEP and -0.12 ± 0.06 °C decade-1 for RICH). The second period from 1980 to the end of the records shows significant warming trends (0.25 ± 0.05 °C decade-1 for both NCEP and RICH). Above the tropopause a persistent cooling trend is clearly seen in the lower stratosphere both in the pre-1980s 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-1980s 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 stratosphere is a persistent feature from the tropics up to 60 north for all months. At polar latitudes competing dynamical and radiative processes are reducing the statistical

  12. Possible methane-induced polar warming in the early Eocene.

    PubMed

    Sloan, L C; Walker, J C; Moore, T C; Rea, D K; Zachos, J C

    1992-05-28

    Reconstructions of early Eocene climate depict a world in which the polar environments support mammals and reptiles, deciduous forests, warm oceans and rare frost conditions. At the same time, tropical sea surface temperatures are interpreted to have been the same as or slightly cooler than present values. The question of how to warm polar regions of Earth without noticeably warming the tropics remains unresolved; increased amounts of greenhouse gases would be expected to warm all latitudes equally. Oceanic heat transport has been postulated as a mechanism for heating high latitudes, but it is difficult to explain the dynamics that would achieve this. Here we consider estimates of Eocene wetland areas and suggest that the flux of methane, an important greenhouse gas, may have been substantially greater during the Eocene than at present. Elevated methane concentrations would have enhanced early Eocene global warming, and also might specifically have prevented severe winter cooling of polar regions because of the potential of atmospheric methane to promote the formation of optically thick, polar stratospheric ice clouds.

  13. Nitrogen compounds in Titan's stratosphere

    NASA Astrophysics Data System (ADS)

    Coustenis, A.; Cirs Investigation Team

    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 stratosphere 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.

  14. Total Hydrogen Budget of the Equatorial Upper Stratosphere

    DTIC Science & Technology

    2010-02-24

    the Limb Infrared Monitor of the Stratosphere (LIMS) and the Stratospheric and Meso- spheric Sounder (SAMS) on Nimbus 7 and from HALOE have revealed...and methane in the upper stratosphere: An examination of some of the Nimbus 7 measure- ments, J. Geophys. Res., 94(D6), 8474 – 8484, doi:10.1029...L. Gordley, J. C. Gille, and P. L. Bailey (1984), Implications of the stratospheric water vapor distributions as determined from the Nimbus 7 LIMS

  15. Warm and Cool Dinosaurs.

    ERIC Educational Resources Information Center

    Mannlein, Sally

    2001-01-01

    Presents an art activity in which first grade students draw dinosaurs in order to learn about the concept of warm and cool colors. Explains how the activity also helped the students learn about the concept of distance when drawing. (CMK)

  16. Reconciling Warming Trends

    NASA Technical Reports Server (NTRS)

    Schmidt, Gavin A.; Shindell, Drew T.; Tsigaridis, Konstantinos

    2014-01-01

    Climate models projected stronger warming 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.

  17. The impact of polar stratospheric ozone loss on Southern Hemisphere stratospheric circulation and climate

    NASA Astrophysics Data System (ADS)

    Keeble, J.; Braesicke, P.; Abraham, N. L.; Roscoe, H. K.; Pyle, J. A.

    2014-07-01

    The impact of polar stratospheric ozone loss resulting from chlorine activation on polar stratospheric 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 stratospheric temperatures and an increase of >6 K in the upper stratosphere. 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 stratosphere and increased dynamical heating in the upper stratosphere. The cooling of the polar lower stratosphere leads, through thermal wind balance, to an acceleration of the polar vortex and delays its breakdown by ~2 weeks. A link between lower stratospheric zonal wind speed, the vertical component of the EP flux, Fz, and the residual mean vertical circulation, 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 stratospheric signals modelled in this study propagate down to the troposphere, and lead to significant surface changes in December.

  18. Lower Stratospheric Measurement Issues Workshop Report

    NASA Technical Reports Server (NTRS)

    Schmeltekopf, Arthur L.

    1992-01-01

    The Lower Stratospheric Measurement Issues workshop was held on 17-19 Oct. 1990. The 3-day workshop was sponsored by the Atmospheric Effects of Stratospheric 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 stratosphere, 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.

  19. Polar stratospheric clouds inferred from satellite data

    NASA Astrophysics Data System (ADS)

    1986-11-01

    Anomalously high radiances from the ozone channel of the Limb Infra-red Monitor of the Statosphere (LIMS) sounding instrument have been observed in the Northern Hemisphere winter lower stratosphere. Such events, thought to be due to polar stratospheric clouds (PSCs) are examined further by computing relative humidities using Stratospheric Sounding Unit (SSU) temperatures and water vapor measurements from the LIMS Map Archive Tape (MAT) 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%. 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 10 September at 20 km. This result has important implications for a number of proposed explanations for the Antarctic ozone hole.

  20. Observations of lightning in the stratosphere

    NASA Technical Reports Server (NTRS)

    Boeck, William L.; Vaughan, Otha H., Jr.; Blakeslee, Richard J.; Vonnegut, Bernard; Brook, Marx; Mckune, John

    1995-01-01

    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 stratosphere above thunderstorms. These images were obtained on several recent shuttle flights while conducting the Mesoscale Lightning Experiment (MLE). The images of stratospheric lightning illustrate the variety of filamentary and broad vertical discharges in the stratosphere 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.

  1. Composition and chemistry of Titan's stratosphere.

    PubMed

    Bézard, Bruno

    2009-02-28

    Our present knowledge of the composition and chemistry of Titan's stratosphere is reviewed. Thermal measurements by the Cassini spacecraft show that the mixing ratios of all photochemical species, except ethylene, increase with altitude at equatorial and southern latitudes, reflecting transport from a high-altitude source to a condensation sink in the lower stratosphere. Most compounds are enriched at latitudes northward of 45 degrees N, a consequence of subsidence in the winter polar vortex. This enrichment is much stronger for nitriles and complex hydrocarbons than for ethane and acetylene. Titan's chemistry originates from breakdown of methane due to photodissociation in the upper atmosphere and catalytical reactions in the stratosphere, and from destruction of nitrogen both by UV photons and electrons. Photochemistry also produces haze particles made of complex refractory material, albeit at a lower rate than ethane, the most abundant gas product. Haze characteristics (vertical distribution, physical and spectral properties) inferred by several instruments aboard Cassini/Huygens are discussed here.

  2. Sources of particulates in the upper stratosphere

    NASA Astrophysics Data System (ADS)

    Bigg, E. Keith

    2011-10-01

    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 stratosphere included some that resembled viruses and cocci, the latter being one of the organisms cultured from upper stratospheric air in a recent experiment. A plausible source of the stratospheric, 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.

  3. Formation of model polar stratospheric cloud films

    NASA Technical Reports Server (NTRS)

    Middlebrook, Ann M.; Koehler, Birgit G.; Mcneill, Laurie S.; Tolbert, Margaret A.

    1992-01-01

    Fourier transform infrared spectroscopy was used to examine the competitive growth of films representative of polar stratospheric clouds. These experiments show that either crystalline nitric acid trihydrate (beta-NAT) or amorphous films with H2O:HNO3 ratios close to 3:1 formed at temperatures 3-7 K warmer than the ice frost point under stratospheric pressure conditions. In addition, with higher HNO3 pressure, we observed nitric acid dihydrate (NAD) formation at temperatures warmer than ice formation. However, our experiments also show that NAD surfaces converted to beta-NAT upon exposure to stratospheric water pressures. Finally, we determined that the net uptake coefficient for HNO3 on beta-NAT is close to unity, whereas the net uptake coefficient for H2O is much less.

  4. Response of Global Ocean Temperature to the Sun's Quasi-Decadal UV Radiative Forcing of the Stratosphere

    NASA Astrophysics Data System (ADS)

    White, W. B.

    2004-12-01

    Earth's climate system experiences quasi-decadal signals in the tropical global-average temperature in the upper ocean (), the troposphere (), and lower stratosphere (), with changes of 0.1K, 0.2K, and 1.0K respectively. These temperature signals fluctuated in fixed phase with the quasi-decadal signal in the Sun's irradiance. White et al. (2003a) diagnosed the thermal budget of the quasi-decadal signal in the tropics, finding the anomalous warming tendency driven by downward sensible-plus-latent heat flux () anomalies. Here we find the latter driven by anomalously warm air-sea temperature differences, with anomalies larger than anomalies and leading by ˜1 year. To determine how this happens, we diagnose the thermal budget of the quasi-decadal signal in the tropical atmosphere (20oS to 20oN) using the NCEP/DOE reanalysis data set. We find the quasi-decadal signal in the Sun's UV radiative forcing of the lower stratosphere temperature anomalies balanced by anomalous longwave radiation to space and to the troposphere below, and by anomalous thermal convection. The latter produced an anomalous warming tendency in the lower troposphere during anomalous cool lower stratosphere temperature. It has two components; i.e. the anomalous convection of the mean thermal gradient and the mean convection of the anomalous thermal gradient. We find the anomalous warming tendency in the lower troposphere driven principally by the latter component, yielding positive anomalous air-sea temperature differences and downward anomalies that are responsible for the anomalous warming tendency.

  5. Large-scale dynamics of the stratosphere and mesosphere during the MAP/WINE campaign winter 1983 to 1984 in comparison with other winters

    NASA Technical Reports Server (NTRS)

    Petzoldt, K.

    1989-01-01

    For the MAP/WINE winter temperature and wind measurements of rockets were combined with SSU radiances (Stratospheric 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 stratospheric warmings. The meridional gradient of the potential vorticity and focusing of wave activity is compared with derived data from satellite observations during other winters.

  6. Polar Warming Drivers

    NASA Astrophysics Data System (ADS)

    McDunn, T. L.; Bougher, S. W.; Mischna, M. A.; Murphy, J. R.

    2012-12-01

    Polar warming is a dynamically induced temperature enhancement over mid-to-high latitudes that results in a reversed (poleward) meridional temperature gradient. This phenomenon was recently characterized over the 40-90 km altitude region [1] based on nearly three martian years of Mars Climate Sounder observations [2, 3]. Here we investigate which forcing mechanisms affect the magnitude and distribution of the observed polar warming by conducting simulations with the Mars Weather Research and Forecasting General Circulation Model [4, 5]. We present simulations confirming the influence topography [6] and dust loading [e.g., 7] have upon polar warming. We then present simulations illustrating the modulating influence gravity wave momentum deposition exerts upon polar warming, consistent with previous modeling studies [e.g., 8]. The results of this investigation suggest the magnitude and distribution of polar warming in the martian middle atmosphere is modified by gravity wave activity and that the characteristics of the gravity waves that most significantly affect polar warming vary with season. References: [1] McDunn, et al., 2012 (JGR), [2]Kleinböhl, et al., 2009 (JGR), [3] Kleinböhl, et al., 2011 (JQSRT), [4] Richardson, et al., 2007 (JGR), [5] Mischna, et al., 2011 (Planet. Space Sci.), [6] Richardson and Wilson, 2002 (Nature), [7] Haberle, et al., 1982 (Icarus), [8] Barnes, 1990 (JGR).

  7. Measurements of Chlorine Partitioning in the Winter Arctic Stratosphere

    NASA Technical Reports Server (NTRS)

    Stachnik, R.; Salawitch, R.; Engel, A.; Schmidt, U.

    1999-01-01

    Under the extremely cold conditions in the polar winter stratosphere, heterogeneous reactions involving HCl and CIONO(sub 2) on the surfaces of polar stratospheric cloud particles can release large amounts of reactive chlorine from these reservoirs leading to rapid chemical loss of ozone in the Arctic lower stratosphere during late winter and early spring.

  8. Is stratospheric air getting younger with time?

    NASA Astrophysics Data System (ADS)

    Monge-Sanz, Beatriz; Chipperfield, Martyn; Dee, Dick; Simmons, Adrian; Stiller, Gabriele

    2014-05-01

    Most climate models have predicted that with the increase in greenhouse gases concentrations, the stratospheric 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 stratospheric simulations with a chemistry transport model (CTM) to evaluate the stratospheric 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 stratosphere. Given this agreement, we have used our simulations to quantify interannual variability and trends in the stratospheric 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 stratospheric 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.

  9. Jovian Stratospheric Circulation: driven radiatively or mechanically?

    NASA Astrophysics Data System (ADS)

    Zhang, Xi; Shia, Run-Lie; Showman, Adam; Yung, Yuk

    2013-04-01

    The existence of large-scale stratospheric circulation has been hypothesized since the 1990s (e.g., Conrath et al. 1990; West et al. 1992). The evidences come from the recent observations of stratospheric tracers such as hydrogen cyanide (HCN), carbon dioxide (CO2), acetylene (C2H2) and ethane (C2H6) (Lellouch et al. 2006; Nixon et al. 2010). Previous studies (e.g., Friedson et al. 1999; Liang et al. 2005) also proposed that horizontal eddy mixing affects meridional transport processes. But the relative roles of diffusion (eddy-mixing) and advection in the horizontal transport are highly uncertain (Lellouch et al., 2006). On the other hand, whether the stratospheric circulation on Jupiter is induced by differential heating or mechanical forcing from below is still debated (e.g., Conrath et al., 1990; West et al., 1992), because the lower stratosphere of Jupiter might not be purely radiatively controlled (Simon-Miller et al., 2006; Zhang et al., 2012). In order to investigate the circulation pattern in detail, we introduce a two-dimensional photochemical-diffusive-advective model to simulate the distribution of stratospheric hydrocarbons. Analytical solutions are derived to gain the physical insight of the coupled chemical-transport processes, and validate the numerical methods (Zhang et al., 2013). The meridional transport processes are constrained using the latitudinal distributions of C2H2 and C2H6 retrieved from Cassini spacecraft measurements during Jupiter flyby in 2000 (Zhang et al., 2012). The derived residual mean circulation pattern shows inconsistency with the instantaneous zonally averaged radiative forcing map during the Cassini flyby (Zhang, 2012), implying that the lower stratospheric circulation might be partly mechanically driven, as is the case for the Brewer-Dobson circulation on Earth. This research was supported in part by NASA NNX09AB72G grant to the California Institute of Technology. XZ was supported by the Bisgrove Fellowship in the

  10. A Stratospheric Mixing and Transport Sampler

    NASA Technical Reports Server (NTRS)

    Sparling, Lynn

    1999-01-01

    The mixing and transport of stratospheric chemical species occurs by a variety of physical mechanisms on a range of length and time scales. Slow vertical diffusion resembles Taylor diffusion in pipe flow, while rapid stirring by chaotic advection is essentially a "baker's transformation", via the stretching and folding of material lines in the flow. Other examples include global scale transport by large organized flow structures, such as the winter stratospheric "eggbeater" that brings tropical air to the north pole. This presentation is a survey of these different mixing and transport phenomena and how we see their signatures in observations of chemical tracers.

  11. Advanced laser stratospheric monitoring systems analyses

    NASA Technical Reports Server (NTRS)

    Larsen, J. C.

    1984-01-01

    This report describes the software support supplied by Systems and Applied Sciences Corporation for the study of Advanced Laser Stratospheric 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 stratospheric species from space.

  12. Y-12 Plant Stratospheric Ozone Protection plan

    SciTech Connect

    1995-09-01

    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 Stratospheric 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 Stratospheric Ozone Protection Program.

  13. Incorporation of stratospheric acids into water ice

    NASA Technical Reports Server (NTRS)

    Elliott, Scott; Turco, Richard P.; Toon, Owen B.; Hamill, Patrick

    1990-01-01

    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 stratospheric 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 stratosphere.

  14. The Chemistry and Physics of Stratospheric Ozone

    NASA Astrophysics Data System (ADS)

    Friedl, Randall R.

    Perhaps no other environmental issue has captured as much widespread public interest and concern as stratospheric ozone depletion due to man-made chlorofluorocarbons (CFCs). Increasing scientific understanding of the connections between CFCs and global-scale ozone changes, highlighted by observations of dramatic ozone loss in the Antarctic, has led to a landmark international treaty and subsequent treaty amendments. As outgrowths of these developments, stratospheric ozone depletion has found its way into science fiction fare and the term “ozone hole” has become part of the English lexicon.

  15. On the Stratospheric Chemistry of Hydrogen Cyanide

    NASA Technical Reports Server (NTRS)

    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.

    2006-01-01

    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 stratospheric 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 stratosphere. 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.

  16. Climate change reduces warming potential of nitrous oxide by an enhanced Brewer-Dobson circulation

    NASA Astrophysics Data System (ADS)

    Kracher, Daniela; Reick, Christian H.; Manzini, Elisa; Schultz, Martin G.; Stein, Olaf

    2016-06-01

    The Brewer-Dobson circulation (BDC), which is an important driver of the stratosphere-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 stratosphere, 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 warming 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 warming 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.

  17. Modeling the effects of UV variability and the QBO on the troposphere-stratosphere system. Part II: The troposphere

    SciTech Connect

    Rind, D.; Balachandran, N.K.

    1995-08-01

    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 stratosphere/upper troposphere warms, 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 stratosphere/upper troposphere cools. Cooling or warming 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 stratosphere, in response to the increased vertical shear of the zonal winds; therefore, it is less effective in warming the polar lower stratosphere. 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.

  18. Lidar observations of the stratospheric aerosol - California, October 1972 to March 1974

    NASA Technical Reports Server (NTRS)

    Russell, P. B.; Viezee, W.; Hake, R. D., Jr.; Collis, R. T. H.

    1976-01-01

    The paper describes the results of a series of 30 observations of stratospheric aerosol made with a ground-based lidar on the North Pacific Coast during a period relatively uninfluenced by major volcanic penetrations and displaying a relative temporal minimum in particulate content. The objectives were to provide a record of aerosol behavior during this intervolcanic period, to compare this behavior with that revealed by previous studies using a variety of techniques, and to provide comparative data on the stratospheric aerosol by conducting joint lidar and aircraft observations. Determination of scattering profile ratios from lidar signal profiles and analysis of experimental errors are described. Analysis of the data shows that significant temporal variability of the aerosol was observed, probably of nonvolcanic origin. Much of the variability was confined to the 23-30 km height region, above the major peak in scattering ratio. The evidence is that this is not due to influxes of extraterrestrial material. Vertical motions of the centroid of the scattering ratio peak were recorded during the 1973 stratospheric warming, and illustrate the value of lidar's ability to monitor temporal variations of vertical structure.

  19. On connections between the stratospheric polar vortex and sea ice in the Arctic

    NASA Astrophysics Data System (ADS)

    Lukovich, J. V.; Barber, D. G.

    2009-12-01

    The unprecedented decline in sea ice extent and thickness in the Arctic in the early part of the 21st century establishes conditions conducive to increased communication between oceanic, sea-ice and atmospheric phenomena. In this study we explore the correspondence between stratospheric dynamic variability in winter and changes in sea ice in the Arctic. Investigated in particular are anomalies and trends in Eliassen-Palm flux components in the northern hemisphere to determine changes in upward wave propagation in response to an accelerated decline in Arctic ice cover in the early part of the 21st century. Connections between the strength and position of the polar vortex and changes in sea ice extent, concentration, and motion are examined in the context of sudden stratospheric warmings and vortex splitting and displacement events. Relative vorticity is used to study the permeability of the polar vortex in response to storm activity in the Arctic with reduced ice cover. Initial results from this analysis suggest a decline in upward wave propagation in winter and an increase in upward wave propagation in fall in recent decades. Spatial coincidence is observed between composites of surface winds for years associated with vortex displacement events and record lows in ice extent. The implications of a poleward increase in cyclonic activity from 70 °N - 80 °N during spring and summer for seasonal variations in the stratospheric polar vortex are also examined.

  20. Fiber-Optic Coupled Lidar Receiver System to Measure Stratospheric Ozone

    NASA Technical Reports Server (NTRS)

    Harper, David Brent; Elsayed-Ali, Hani

    1998-01-01

    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 stratosphere, 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 warming. On the other hand, ozone in the stratosphere 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 stratosphere. 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.

  1. Observed connections of Arctic stratospheric ozone extremes to Northern Hemisphere surface climate

    NASA Astrophysics Data System (ADS)

    Ivy, Diane J.; Solomon, Susan; Calvo, Natalia; Thompson, David W. J.

    2017-02-01

    We present observational evidence for linkages between extreme Arctic stratospheric ozone anomalies in March and Northern Hemisphere tropospheric climate in spring (March–April). Springs characterized by low Arctic ozone anomalies in March are associated with a stronger, colder polar vortex and circulation anomalies consistent with the positive polarity of the Northern Annular Mode/North Atlantic Oscillation in March and April. The associated spring tropospheric circulation anomalies indicate a poleward shift of zonal winds at 500 hPa over the North Atlantic. Furthermore, correlations between March Arctic ozone and March–April surface temperatures reveal certain regions where a surprisingly large fraction of the interannual variability in spring surface temperatures is associated with interannual variability in ozone. We also find that years with low March Arctic ozone in the stratosphere display surface maximum daily temperatures in March–April that are colder than normal over southeastern Europe and southern Asia, but warmer than normal over northern Asia, adding to the warming from increasing well-mixed greenhouse gases in those locations. The results shown here do not establish causality, but nevertheless suggest that March stratospheric ozone is a useful indicator of spring averaged (March–April) tropospheric climate in certain Northern Hemispheric regions.

  2. Investigating Type I Polar Stratospheric Cloud Formation Mechanisms with POAM Satellite Observations

    NASA Technical Reports Server (NTRS)

    Strawa, Anthony W.; Drdla, K.; Fromm, M.; Hoppel, K.; Browell, E.; Hamill, P.; Dempsey, D.; Gore, Warren J. (Technical Monitor)

    2001-01-01

    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 stratosphere. 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 warming. 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 stratospheric aerosols and Polar Stratospheric 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.

  3. Global warming on trial

    SciTech Connect

    Broeker, W.S.

    1992-04-01

    Jim Hansen, a climatologist at NASA's Goddard Space Institute, is convinced that the earth's temperature is rising and places the blame on the buildup of greenhouse gases in the atmosphere. Unconvinced, John Sununu, former White House chief of staff, doubts that the warming will be great enough to produce serious threat and fears that measures to reduce the emissions would throw a wrench into the gears that drive the Unites States' troubled economy. During his three years at the White House, Sununu's view prevailed, and although his role in the debate has diminished, others continue to cast doubt on the reality of global warming. A new lobbying group called the Climate Council has been created to do just this. Burning fossil fuels is not the only problem; a fifth of emissions of carbon dioxide now come from clearing and burning forests. Scientists are also tracking a host of other greenhouse gases that emanate from a variety of human activities; the warming effect of methane, chlorofluorocarbons and nitrous oxide combined equals that of carbon dioxide. Although the current warming from these gases may be difficult to detect against the background noise of natural climate variation, most climatologists are certain that as the gases continue to accumulate, increases in the earth's temperature will become evident even to skeptics. If the reality of global warming were put on trial, each side would have trouble making its case. Jim Hansen's side could not prove beyond a reasonable doubt that carbon dioxide and other greenhouse gases have warmed the planet. But neither could John Sununu's side prove beyond a reasonable doubt that the warming expected from greenhouse gases has not occurred. To see why each side would have difficulty proving its case, this article reviews the arguments that might be presented in such a hearing.

  4. Composite Materials With Uncured Epoxy Matrix Exposed in Stratosphere During NASA Stratospheric Balloon Flight

    NASA Technical Reports Server (NTRS)

    Kondyurin, Alexey; Kondyurina, Irina; Bilek, Marcela; de Groh, Kim K.

    2013-01-01

    A cassette of uncured composite materials with epoxy resin matrixes was exposed in the stratosphere (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 stratosphere 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 stratosphere. The composites were cured on Earth after landing. Analysis of the cured composites showed that the polymer matrix remains active under stratospheric conditions. The results can be used for predicting curing processes of polymer composites in a free space environment during an orbital space flight.

  5. International Conference on Problems Related to the Stratosphere

    NASA Technical Reports Server (NTRS)

    Huntress, W., Jr.

    1977-01-01

    The conference focused on four main areas of investigation: laboratory studies and stratospheric chemistry and constituents, sources for and chemical budget of stratospheric halogen compounds, sources for and chemical budget of stratospheric nitrous oxide, and the dynamics of decision making on regulation of potential pollutants of the stratosphere. 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 stratospheric pollutants were examined extensively.

  6. Recent Increases in Stratospheric HCl: Stratospheric Dynamics versus the Montreal Protocol

    NASA Astrophysics Data System (ADS)

    Chipperfield, Martyn; Mahieu, Emmanuel; Notholt, Justus

    2014-05-01

    Long-lived chlorine-containing source gases, such as chlorofluorocarbons (CFCs), are transported into the stratosphere 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 stratosphere, chlorine mainly forms the reservoir HCl, providing an alternative method for monitoring the progress of the Montreal Protocol. A maximum in stratospheric 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 stratospheric 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 stratosphere. 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 stratosphere 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 stratospheric chlorine. This dynamical variability could also significantly affect the evolution of stratospheric ozone and must be accounted for when searching for signs of ozone recovery.

  7. Stratospheric geoengineering impacts on El Niño/Southern Oscillation

    NASA Astrophysics Data System (ADS)

    Gabriel, C. J.; Robock, A.

    2015-10-01

    To examine the impact of proposed stratospheric geoengineering schemes on the amplitude and frequency of El Niño/Southern Oscillation (ENSO) variations we examine climate model simulations from the Geoengineering Model Intercomparison Project (GeoMIP) G1-G4 experiments. Here we compare tropical Pacific behavior under anthropogenic global warming (AGW) using several scenarios: an instantaneous quadrupling of the atmosphere's CO2 concentration, a 1 % annual increase in CO2 concentration, and the representative concentration pathway resulting in 4.5 W m-2 radiative forcing at the end of the 21st century, the Representative Concentration Pathway 4.5 scenario, with that under G1-G4 and under historical model simulations. Climate models under AGW project relatively uniform warming across the tropical Pacific over the next several decades. We find no statistically significant change in ENSO frequency or amplitude under stratospheric geoengineering as compared with those that would occur under ongoing AGW, although the relative brevity of the G1-G4 simulations may have limited detectability of such changes. We also find that the amplitude and frequency of ENSO events do not vary significantly under either AGW scenarios or G1-G4 from the variability found within historical simulations or observations going back to the mid-19th century. Finally, while warming of the Niño3.4 region in the tropical Pacific is fully offset in G1 and G2 during the 40-year simulations, the region continues to warm significantly in G3 and G4, which both start from a present-day climate.

  8. Two mechanisms of stratospheric ozone loss in the Northern Hemisphere, studied using data assimilation of Odin/SMR atmospheric observations

    NASA Astrophysics Data System (ADS)

    Sagi, Kazutoshi; Pérot, Kristell; Murtagh, Donal; Orsolini, Yvan

    2017-02-01

    Observations from the Odin/Sub-Millimetre Radiometer (SMR) instrument have been assimilated into the DIAMOND model (Dynamic Isentropic Assimilation Model for OdiN Data), in order to estimate the chemical ozone (O3) loss in the stratosphere. This data assimilation technique is described in Sagi and Murtagh (2016), in which it was used to study the inter-annual variability in ozone depletion during the entire Odin operational time and in both hemispheres. Our study focuses on the Arctic region, where two O3 destruction mechanisms play an important role, involving halogen and nitrogen chemical families (i.e. NOx = NO and NO2), respectively. The temporal evolution and geographical distribution of O3 loss in the low and middle stratosphere have been investigated between 2002 and 2013. For the first time, this has been done based on the study of a series of winter-spring seasons over more than a decade, spanning very different dynamical conditions. The chemical mechanisms involved in O3 depletion are very sensitive to thermal conditions and dynamical activity, which are extremely variable in the Arctic stratosphere. We have focused our analysis on particularly cold and warm winters, in order to study the influence this has on ozone loss. The winter 2010/11 is considered as an example for cold conditions. This case, which has been the subject of many studies, was characterised by a very stable vortex associated with particularly low temperatures, which led to an important halogen-induced O3 loss occurring inside the vortex in the lower stratosphere. We found a loss of 2.1 ppmv at an altitude of 450 K in the end of March 2011, which corresponds to the largest ozone depletion in the Northern Hemisphere observed during the last decade. This result is consistent with other studies. A similar situation was observed during the winters 2004/05 and 2007/08, although the amplitude of the O3 destruction was lower. To study the opposite situation, corresponding to a warm and

  9. Stratospheric aerosol—Observations, processes, and impact on climate

    NASA Astrophysics Data System (ADS)

    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

    2016-06-01

    Interest in stratospheric aerosol and its role in climate have increased over the last decade due to the observed increase in stratospheric 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 stratospheric aerosol research since the last comprehensive assessment of stratospheric 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 stratospheric 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 stratospheric aerosol climatology. Currently, changes in stratospheric 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 stratospheric 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 stratospheric 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 stratospheric aerosol processes is coupled to radiation and/or stratospheric chemistry modules to account for relevant feedback processes.

  10. Stratospheric Aerosol--Observations, Processes, and Impact on Climate

    NASA Technical Reports Server (NTRS)

    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

    2016-01-01

    Interest in stratospheric aerosol and its role in climate have increased over the last decade due to the observed increase in stratospheric 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 stratospheric aerosol research since the last comprehensive assessment of stratospheric 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 stratospheric 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 stratospheric aerosol climatology. Currently, changes in stratospheric 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 stratospheric 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 stratospheric 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 stratospheric aerosol processes is coupled to radiation and/or stratospheric chemistry modules to account for relevant feedback processes.

  11. Fourier spectroscopy of the stratospheric emission

    NASA Technical Reports Server (NTRS)

    Carli, B.; Mencaraglia, F.; Bonetti, A.

    1980-01-01

    Stratospheric emission spectra in the submillimeter range have been recorded with a resolution of 0.0033/cm with a balloon-borne interferometer. Several minor atmospheric constituents have been identified in a preliminary analysis of the spectra; these are water vapor, oxygen, ozone isotopes, nitric acid, nitrous oxide, hydrofluoric and hydrochloric acids, and carbon monoxide.

  12. SOFIA - Stratospheric Observatory For Infrared Astronomy

    NASA Technical Reports Server (NTRS)

    Erickson, E. F.

    1992-01-01

    The features and scientific aims of SOFIA (Stratospheric 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.

  13. Age as a diagnostic of stratospheric transport

    NASA Technical Reports Server (NTRS)

    Hall, Timothy M.; Plumb, R. Alan

    1994-01-01

    Estimates of stratospheric 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 stratosphere, 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 stratospheric 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 stratospheric 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.

  14. Stratospheric Aerosols: The Transfer of Scientific Information.

    ERIC Educational Resources Information Center

    Feidler, Anita; Hurt, C. D.

    1986-01-01

    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 stratospheric aerosols have been prominently discussed in the popular press. (Author/EM)

  15. Stratospheric General Circulation with Chemistry Model (SGCCM)

    NASA Technical Reports Server (NTRS)

    Rood, Richard B.; Douglass, Anne R.; Geller, Marvin A.; Kaye, Jack A.; Nielsen, J. Eric; Rosenfield, Joan E.; Stolarski, Richard S.

    1990-01-01

    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, Stratospheric Data Analysis System (STRATAN).

  16. The Stratosphere 1981: Theory and measurements

    NASA Technical Reports Server (NTRS)

    1982-01-01

    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 stratosphere were reviewed.

  17. Chemistry-Climate Models of the Stratosphere

    NASA Technical Reports Server (NTRS)

    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)

    2001-01-01

    Over the last decade, improved computer power has allowed three-dimensional models of the stratosphere 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.

  18. The use of lidar for stratospheric measurements

    NASA Technical Reports Server (NTRS)

    Mccormick, M. P.

    1977-01-01

    Stratospheric measurements possible with ground-based, airborne, and satellite-borne lidar systems are reviewed. The instruments, basic equations, and formats normally used for various scattering and absorption phenomena measurements are presented including a discussion of elastic, resonance, Raman, and fluorescence scattering techniques.

  19. Large-Scale Stratospheric Transport Processes

    NASA Technical Reports Server (NTRS)

    Plumb, R. Alan

    2001-01-01

    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 stratosphere. 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.

  20. Chlorine Monoxide in the Antarctic Spring Stratosphere.

    NASA Astrophysics Data System (ADS)

    Jaramillo-Ayerbe, Mauricio

    1988-06-01

    A series of observations of stratospheric chlorine monoxide (ClO) were carried out during the austral springs of 1986 and 1987 in McMurdo Station, Antarctica, as part of two experimental campaigns sent to investigate the seasonal decrease in ozone over the antarctic continent (the ozone "hole"). Measurements of the vertical distribution of ClO were obtained by high resolution ground-based emission spectroscopy at 278 GHz, using the Stony Brook mm-wave receiver. They show the presence of an anomalous layer of lower stratospheric ClO which is not observed at other latitudes. This anomalous layer is centered at ~20 km altitude and exhibits a pronounced diurnal variation, reaching a maximum at midday and disappearing at night. During the period of Sep. 20-24, 1987, the lower-stratospheric ClO had a maximum volume mixing ratio of 1.8_sp{+0cdot5}{ -0cdot9} ppbv. A normal ClO layer centered at ~36 km was also observed, with concentrations and diurnal behavior similar to those seen in tropical latitudes. These findings are evidence of anomalous chlorine chemistry taking place in the lower stratosphere during the antarctic spring, and indicate that increasing anthropogenic chlorine is a prime causative agent in the formation of the ozone hole.

  1. STRATOSPHERIC OZONE PROTECTION: AN EPA ENGINEERING PERSPECTIVE

    EPA Science Inventory

    Chlorine released into the atmosphere is a major factor in the depletion of the protective stratospheric 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...

  2. Space and Earth Observations from Stratospheric Balloons

    NASA Astrophysics Data System (ADS)

    Peterzen, Steven; Ubertini, Pietro; Masi, Silvia; Ibba, Roberto; Ivano, Musso; Cardillo, Andrea; Romeo, Giovanni; Dragøy, Petter; Spoto, Domenico

    Stratospheric 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 stratospheric 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 stratospheric 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 stratospheric 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

  3. Nitrogen fertiliser and stratospheric ozone - Latitudinal effects

    NASA Technical Reports Server (NTRS)

    Whitten, R. C.; Borucki, W. J.; Capone, L. A.; Riegel, C. A.; Turco, R. P.

    1980-01-01

    Substantial increases in atmospheric N2O resulting from the increased use of nitrogen fertilizers might cause large (to 10%) decreases in the stratospheric ozone content. Such ozone decreases would be caused by catalytic reaction cycles involving odd-nitrogen that is formed by N2O decomposition in the upper stratosphere. 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 stratospheric 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 stratospheric chlorine levels on predicted ozone changes are also discussed.

  4. Intraseasonal oscillations of stratospheric ozone above Switzerland

    NASA Astrophysics Data System (ADS)

    Studer, Simone; Hocke, Klemens; Kämpfer, Niklaus

    2012-01-01

    GROMOS, the ground-based millimeter-wave ozone spectrometer, continuously measures the stratospheric ozone profile between the altitudes of 20 and 65 km above Bern (46°57‧N, 7°27‧E) since November 1994. Characteristics of intraseasonal oscillations of stratospheric ozone are derived from the long-term data set. Spectral analysis gives evidence for a dominant oscillation period of about 20 days in the lower and middle stratosphere during winter time. A strong 20-day wave is also found in collocated geopotential height measurements of the microwave limb sounder onboard the Aura satellite (Aura/MLS) confirming the ground-based observations of GROMOS and underlining the link between ozone and dynamics. Remarkably, the ozone series of GROMOS show an interannual variability of the strength of intraseasonal oscillations of stratospheric ozone. The interannual variability of ozone fluctuations is possibly due to influences of planetary wave forcing and the quasi-biennial oscillation (QBO) on the meridional Brewer-Dobson circulation of the middle atmosphere. In detail, time series of the mean amplitude of ozone fluctuations with periods ranging from 10 to 60 days are derived at fixed pressure levels. The mean amplitude series are regarded as a measure of the strength of intraseasonal oscillations of stratospheric ozone above Bern. After deseasonalizing the mean amplitude series, we find QBO-like amplitude modulations of the intraseasonal oscillations of ozone. The amplitudes of the intraseasonal oscillations are enhanced by a factor of 2 in 1997, 2001, 2003, and 2005. QBO-like variations of intraseasonal oscillations are also present in wind, temperature and other parameters above Bern as indicated by meteorological reanalyses of the European Centre for Medium-range Weather Forecasts (ECMWF). Further, intercomparisons of interannual variability of intraseasonal tropospheric and stratospheric oscillations are performed where the NAO index (North-Atlantic oscillation

  5. Stratospheric Sulfuric Acid and Black Carbon Aerosol Measured During POLARIS and its Role in Ozone Chemistry

    NASA Technical Reports Server (NTRS)

    Strawa, Anthony W.; Pueschel, R. F.; Drdla, K.; Verma, S.; Gore, Warren J. (Technical Monitor)

    1998-01-01

    Stratospheric 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 Stratospheric 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 stratospheric aerosol from cooling to warming. Correlations between measured BCA amounts and aircraft usage have been reported. Attempts to link BCA to ozone chemistry and other stratospheric processes have been hindered by questions concerning the amount of BCA that exists in the stratosphere, 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 stratospheric 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

  6. The Evolution of Hydrocarbon Compounds in Saturn's Stratosphere During the 2010 Northern Storm

    NASA Astrophysics Data System (ADS)

    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.

    2013-12-01

    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' (warm regions in the stratosphere 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 stratospheric 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 stratosphere. These species are all expected from photochemical processes in the stratosphere, 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 stratospheric 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

  7. Stratospheric experiments on curing of composite materials

    NASA Astrophysics Data System (ADS)

    Chudinov, Viacheslav; Kondyurin, Alexey; Svistkov, Alexander L.; Efremov, Denis; Demin, Anton; Terpugov, Viktor; Rusakov, Sergey

    2016-07-01

    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 stratospheric flight experiment is an investigation of the effect of the stratospheric 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 stratospheric 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 stratosphere 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 stratospheric flight. The study was supported by RFBR grants 12-08-00970 and 14-08-96011.

  8. Convective transport of very-short-lived bromocarbons to the stratosphere

    NASA Astrophysics Data System (ADS)

    Liang, Q.; Atlas, E.; Blake, D.; Dorf, M.; Pfeilsticker, K.; Schauffler, S.

    2014-01-01

    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 stratospheric 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 warm 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 stratosphere. On global and annual average, CHBr3 and CH2Br2, together, contribute ∼7.7 pptv to the present-day inorganic bromine in the stratosphere. 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 stratosphere (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).

  9. Challenges to producing a long-term stratospheric aerosol climatology for chemistry and climate

    NASA Astrophysics Data System (ADS)

    Thomason, Larry; Vernier, Jean-Paul; Bourassa, Adam; Rieger, Landon; Luo, Beiping; Peter, Thomas; Arfeuille, Florian

    2016-04-01

    Stratospheric 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 stratospheric aerosol as mitigation for global warming. 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 Stratospheric Aerosol Properties (ASAP), extending from 1979 and 2004. It was primarily constructed from the Stratospheric 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.

  10. Modeling Extremely Deep Convection over North America as a Source of Stratospheric Water Vapor

    NASA Astrophysics Data System (ADS)

    Leroy, S. S.; Clapp, C.; Smith, J. B.; Anderson, J. G.

    2015-12-01

    We have run the Advanced Research Weather Research and Forecasting Model (ARW) at scales that numerically resolve convection over a broad swath of the north central U.S. Our intentions were to simulate convective events that generated stratospheric water vapor plumes observed during the SEAC4RS mission, to quantify the amount of water vapor injected into the stratosphere by extremely deep convection, and to investigate ARW as a potential tool to forecast multi-decadal trends in extremely deep convection over North America. We have run ARW for five and a half days beginning at 12 UTC on 26 August 2013 on a 3-km horizontal grid with 50 vertical levels. We used MERRA for the initial conditions and boundary conditions because of its skill in reanalysis of water vapor. ARW was able to simulate many of the fundamental features of deep convection over North America, including specific events. We have shown that the convection simulated by ARW bears many of the features of mesoscale convective systems, including the flow of cold air over warm moist air, cold downdrafts and gust fronts, mid-level inflow, and wedges reminiscent of squall lines. The source of water vapor for the convection is low-level eastward transport into the ARW domain. Convection is initiated where local maxima in equivalent potential temperature of surface air form. Convection regularly penetrates to the level of neutral buoyancy of the surface air and can even influence the concentration of water vapor above. A few convective events inject water vapor above the 400 K potential temperature surface. Surprisingly, deep convective events can also desiccate the upper air, even in the stratosphere. There is clear evidence of convection generating ducted internal gravity waves that propagate upstream to trigger more deep convection. We will present a quantification of the amount of water vapor injected into the stratosphere by extremely deep convection, the causes of desiccation, and the mechanisms

  11. Convective Transport of Very-short-lived Bromocarbons to the Stratosphere

    NASA Technical Reports Server (NTRS)

    Liang, Qing; Atlas, Elliot Leonard; Blake, Donald Ray; Dorf, Marcel; Pfeilsticker, Klaus August; Schauffler, Sue Myhre

    2014-01-01

    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 stratospheric 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 warm 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 stratosphere. On global and annual average, CHBr3 and CH2Br2, together, contribute 7.7 pptv to the present-day inorganic bromine in the stratosphere. 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 stratosphere (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.

  12. Modeling of Solar Radiation Management: A comparison of simulations using reduced solar constant and stratospheric aerosols

    NASA Astrophysics Data System (ADS)

    Kalidindi, Sirisha; Bala, Govindasamy; Modak, Angshuman; Caldeira, Ken

    2014-05-01

    The climatic effects of Solar Radiation Management (SRM) geoengineering have been often modeled by simply reducing the solar constant. This is most likely valid only for space sunshades and not for atmosphere and surface based SRM methods. In this study, a global climate model is used to test if the climate response to SRM by stratospheric aerosols and uniform solar constant reduction are equivalent. Our analysis shows that when global mean warming from a doubling of CO2 is nearly cancelled by both these methods, they are equivalent when important surface and tropospheric climate variables are considered. However, a difference of 1 K in the global mean stratospheric (61-9.8 hPa) temperature is simulated between the two SRM methods. Further, while the global mean surface diffuse radiation increases by about 15-20% and direct radiation decreases by about 8% in the case of sulphate aerosol SRM method, both direct and diffuse radiation decrease by similar fractional amounts (~ -1.5%) when solar constant is reduced. Though the contribution from shaded leaves to gross primary productivity (GPP) increases by 6% in aerosol SRM because of increased diffuse light this increase is almost offset by a 7% decline in sunlit contribution due to reduced direct light. Hence, in the aerosol SRM there is a slight net reduction (~ 1%) in total GPP which is close to the decrease due to solar constant reduction. Based on our results we conclude that the climate states produced by a reduction in solar constant and addition of aerosols into the stratosphere can be considered almost equivalent except for two important aspects: stratospheric temperature change and the partitioning of direct versus diffuse radiation reaching the surface.

  13. Unraveling the empirical relationship between Arctic stratospheric ozone loss and temperature

    NASA Astrophysics Data System (ADS)

    von Hobe, Marc; Grooß, Jens-Uwe; Müller, Rolf

    2014-05-01

    Ever since the discovery of the Antarctic ozone hole it has been recognized that cold temperatures play a key role in fostering strong ozone depletion in the polar stratosphere. Compact negative correlations between total winter ozone loss and vortex area exposed to temperatures below certain threshold values have been demonstrated (e.g. Harris et al., 2010; Rex et al., 2006; Rex et al., 2004). The most commonly used threshold is the NAT equilibrium temperature, but other choices have been suggested, such as the temperature when the rate of chlorine activation on liquid aerosols exceeds a certain limit. Interestingly, both thresholds relate to critical temperatures in the context of heterogeneous chlorine activation, and Harris et al., 2010, stated that original activation (i.e. the activation in early winter) is the most important factor influencing ozone loss. But at least two other key processes - catalytic ozone loss and denitrification - depend directly on temperature, and temperature also controls the stability and therefore the persistence of the polar vortex. Here, we investigate such "vortex area" correlations for a number of different temperature thresholds, as well as direct correlations with vortex mean temperature and with the date of the final warming. We also carry out sensitivity studies using the Chemical Lagrangian Model of the Stratosphere (CLaMS) to investigate the response of ozone loss to temperature modifications for particle formation and growth, surface reaction probabilities and gas phase reactivity separately. Rex et al., Arctic ozone loss and climate change, Geophys. Res. Lett., 31, L04116, 2004. Rex et al., Arctic winter 2005: Implications for stratospheric ozone loss and climate change, Geophys. Res. Lett., 33, L23808, 2006. Harris et al., A closer look at Arctic ozone loss and polar stratospheric clouds, Atmos. Chem. Phys., 10, 8499-8510, 2010.

  14. Comparison of stratospheric temperature profiles from a ground-based microwave radiometer with lidar, radiosonde and satellite data

    NASA Astrophysics Data System (ADS)

    Navas-Guzmán, Francisco; Kämpfer, Niklaus; Haefele, Alexander; Keckhut, Philippe; Hauchecorne, Alain

    2015-04-01

    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 stratosphere is an indicator for climate change as it provides evidence of natural and anthropogenic climate forcing just like surface warming ( [1] and references therein). However, our understanding of the observed stratospheric temperature trend and our ability to test simulations of the stratospheric response to emissions of greenhouse gases and ozone depleting substances remains limited. Stratospheric 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 stratospheric 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 stratospheric 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 stratospheric

  15. Volcanic emissions of SO2 into the stratosphere: global height-resolved observations by MIPAS during 2002-2012

    NASA Astrophysics Data System (ADS)

    Höpfner, Michael; Glatthor, Norbert; Grabowski, Udo; Kellmann, Sylvia; Kiefer, Michael; Linden, Andrea; Stiller, Gabriele; von Clarmann, Thomas; Funke, Bernd; Boone, Christopher D.; Schlager, Hans; Roiger, Anke; Wissmüller, Katharina

    2014-05-01

    The years since about 2000 are characterized by an increasing background stratospheric aerosol loading. Due to its negative radiative forcing this increase has been discussed as one explanation for the so-called global warming hiatus, a decrease in the rise of global temperatures since about 1998 (Solomon et al., Science, 333, 866-870, 2011). The rising aerosol levels are explained by injection of sulphur from small and medium-size volcanic eruptions into the stratosphere (Vernier et al., GRL, 38, 2011). To study this period with atmospheric models it is necessary to gain information about the mass of SO2 reaching stratospheric altitudes globally. Here we present a global distribution of altitude profiles of SO2 between 10 and 22 km as retrieved from MIPAS/Envisat infrared limb-emission observations between June 2002 and April 2012. This dataset is complementary to our earlier work (Höpfner et al., ACP, 13, 10405-10423, 2013) which consisted of the monthly and zonally averaged distributions of SO2 above 15-20 km. The new data are derived from single - as opposed to averaged - MIPAS limb measurements. This global dataset which consists of over 1000 SO2 profiles per day allows tracking of the plumes originating from more than 30 volcanic eruptions in the time period from June 2002 to April 2012 and quantification of their influence on the stratosphere.

  16. Seasonal prediction of the NAO from stratospheric and tropospheric indicators for different data products and index definitions

    NASA Astrophysics Data System (ADS)

    Domeisen, Daniela; Koszalka, Inga

    2016-04-01

    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 stratospheric and tropospheric variables and the NAO index. The response to anomalies in stratospheric polar cap temperatures, as e.g. the negative NAO response observed after major stratospheric sudden warming 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 stratosphere, 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.

  17. A risk-based framework for assessing the effectiveness of stratospheric aerosol geoengineering.

    PubMed

    Ferraro, Angus J; Charlton-Perez, Andrew J; Highwood, Eleanor J

    2014-01-01

    Geoengineering by stratospheric aerosol injection has been proposed as a policy response to warming 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 warming produced by a quadrupling of carbon dioxide concentrations, with one using a layer of sulphate aerosol in the lower stratosphere, 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.

  18. A Risk-Based Framework for Assessing the Effectiveness of Stratospheric Aerosol Geoengineering

    PubMed Central

    Ferraro, Angus J.; Charlton-Perez, Andrew J.; Highwood, Eleanor J.

    2014-01-01

    Geoengineering by stratospheric aerosol injection has been proposed as a policy response to warming 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 warming produced by a quadrupling of carbon dioxide concentrations, with one using a layer of sulphate aerosol in the lower stratosphere, 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

  19. Warm and Cool Cityscapes

    ERIC Educational Resources Information Center

    Jubelirer, Shelly

    2012-01-01

    Painting cityscapes is a great way to teach first-grade students about warm 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,…

  20. Warming Up to Communication.

    ERIC Educational Resources Information Center

    Garner, Lucia Caycedo; Rusch, Debbie

    Daily warm-up exercises are advocated as a means of bridging the gap between previously unrelated activities outside the classroom and immersion into the second language, relaxing the class, and establishing a mood for communication. Variety, careful preparation, assuring that the students understand the activity, feeling free to discontinue an…

  1. Global warming 'confirmed'

    NASA Astrophysics Data System (ADS)

    2011-12-01

    In October, the Berkeley Earth Surface Temperature project, funded in part by climate sceptics, concluded that the Earth is warming based on the most comprehensive review of the data yet. Nature Climate Change talks to the project's director, physicist Richard Muller.

  2. Revelations of a stratospheric circulation: The dynamical transport of hydrocarbons in the stratosphere of Uranus

    SciTech Connect

    McMillan, W.W.

    1992-01-01

    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 stratosphere 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 stratospheric circulation in determining the distribution of hydrocarbons in the stratosphere (0.1-100 mb) of Uranus is investigated with a 2-dimensional photochemical transport model. The stratospheric 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 stratosphere of Uranus. It is determined that advective transport by the stratospheric circulation can account for the essential observed meridional variation of stratospheric 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.

  3. LIMS (Limb Infrared Monitor of the Stratosphere) observation of traveling planetary waves and potential vorticity advection in the stratosphere and mesosphere

    NASA Astrophysics Data System (ADS)

    Dunkerton, Timothy J.

    1991-02-01

    Eastward and westward traveling waves were observed by the Nimbus 7 Limb Infrared Monitor of the Stratosphere (LIMS) during the northern winter 1978-1979. Eastward waves were prevalent in early winter and were involved in a minor Canadian warming in December 1978. A large westward traveling wave, as described by previous authors, was observed in January 1979 during a series of minor warmings. 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 warmings. 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.

  4. Reactions on sulphuric acid aerosol and on polar stratospheric clouds in the Antarctic stratosphere

    SciTech Connect

    Wolff, E.W.; Mulvaney, R.

    1991-06-01

    Heterogeneous chemistry producing active chlorine has been identified as crucial to Antarctic ozone depletion. Most attention has focused on reactions on solid polar stratospheric cloud (PSC) particles, although there is still no satisfactory understanding of the microchemical incorporation of HCl in PSCs. The alternative mechanism involving sulphuric acid aerosol as the reaction surface has been considered at lower latitudes, but its role in the special conditions of the polar stratosphere has been largely ignored. Recent data from the Antarctic stratosphere have suggested the HCl is present in sulphuric acid aerosol that remains liquid even at the lowest stratospheric temperatures. The available laboratory data show that cold, relatively dilute, sulphuric acid is particularly able to take up HCl that is available for reaction provided the aerosol remains liquid. Fast heterogeneous reaction rates compared to those at mid-latitudes will produce active chlorine rapidly. Since the aerosol is present with significant surface area throughout the lower stratosphere, it should be very effective for heterogeneous reaction once temperatures drop. These surfaces, rather than PSCs, could host the initial conversion of Cl to its active form over the Antarctic.

  5. How does downward planetary wave coupling affect polar stratospheric ozone in the Arctic winter stratosphere?

    NASA Astrophysics Data System (ADS)

    Lubis, Sandro W.; Silverman, Vered; Matthes, Katja; Harnik, Nili; Omrani, Nour-Eddine; Wahl, Sebastian

    2017-02-01

    It is well established that variable wintertime planetary wave forcing in the stratosphere controls the variability of Arctic stratospheric ozone through changes in the strength of the polar vortex and the residual circulation. While previous studies focused on the variations in upward wave flux entering the lower stratosphere, here the impact of downward planetary wave reflection on ozone is investigated for the first time. Utilizing the MERRA2 reanalysis and a fully coupled chemistry-climate simulation with the Community Earth System Model (CESM1(WACCM)) of the National Center for Atmospheric Research (NCAR), we find two downward wave reflection effects on ozone: (1) the direct effect in which the residual circulation is weakened during winter, reducing the typical increase of ozone due to upward planetary wave events and (2) the indirect effect in which the modification of polar temperature during winter affects the amount of ozone destruction in spring. Winter seasons dominated by downward wave reflection events (i.e., reflective winters) are characterized by lower Arctic ozone concentration, while seasons dominated by increased upward wave events (i.e., absorptive winters) are characterized by relatively higher ozone concentration. This behavior is consistent with the cumulative effects of downward and upward planetary wave events on polar stratospheric ozone via the residual circulation and the polar temperature in winter. The results establish a new perspective on dynamical processes controlling stratospheric ozone variability in the Arctic by highlighting the key role of wave reflection.

  6. Intercomparison of measurements of stratospheric hydrogen fluoride

    NASA Technical Reports Server (NTRS)

    Mankin, William G.; Coffey, M. T.; Chance, K. V.; Traub, W. A.; Carli, B.; Mencaraglia, F.; Piccioli, S.; Farmer, C. B.; Seals, R. K.

    1990-01-01

    Observations of the vertical profile of hydrogen fluoride (HF) vapor in the stratosphere and of the vertical column amounts of HF above certain altitudes were made using a variety of spectroscopic instruments in the 1982 and 1983 Balloon Intercomparison Campaigns. Both emission instruments working in the far-infrared spectral region and absorption instruments using solar occultation in the 2.5-micron region were employed. No systematic differences were seen in results from the two spectral regions. A mean profile from 20 - 45 km is presented, with uncertainties ranging from 20 to 50 percent. Total columns measured from ground and from 12 km are consistent with the profile if the mixing ratio for HF is small in the troposphere and low stratosphere.

  7. Bifurcation properties of a stratospheric vacillation model

    NASA Technical Reports Server (NTRS)

    Yoden, Shigeo

    1987-01-01

    Nonlinear properties of the stratospheric vacillation model of Holton and Mass (1976) are studied numerically using bifurcation theory. Severe truncation and vertical differencing are used to obtain 81 nonlinear ordinary differential equations with time-dependent variables. Three branches of the steady solutions are determined using Powell's hybrid method and the pseudoarclength continuation method, and a multiplicity of stable steady-state solutions with different vertical structures are found to exist in some range of the bifurcation parameter. Periodic solutions are found which branch off from a steady solution by a Hopf bifurcation. It is suggested that the interannual variability of the stratospheric circulation in the middle and high latitudes during winter may be explained by the multiplicity of steady and periodic stable solutions.

  8. A "Stratospheric Drain" over the Maritime Continent

    NASA Technical Reports Server (NTRS)

    Sherwood, Steve

    1999-01-01

    Evidence is presented from operational rawinsonde data surrounding the maritime continent that the net mass flux near the tropopause is downward over this region, contrary to the behavior of current numerical models. The air is descending year-round, despite mean upward motion below and above the descending layer. This sinking implies the existence of a significant energy-removing process, which is argued to be the injection of cold air by overshooting convective clouds. The mass, energy, and horizontal momentum budgets are examined in reaching these conclusions. The implied cooling effect of convective overshoots can be simulated with a simple, parcel-sorting convective mixing model. The findings contradict the common view that the mean flow enters the stratosphere in this strongly-convecting region, and have important implications for transport of water vapor and other gases into the stratosphere.

  9. Pristine Stratospheric Collections of Cosmic Dust

    NASA Technical Reports Server (NTRS)

    Messenger, S.; Keller, L. P.; Nakamura-Messenger, K.; Clemett, S. J.

    2012-01-01

    Since 1981, NASA has routinely collected interplanetary dust particles (IDPs) in the stratosphere 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 w