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Sample records for summer convective storms

  1. Convective storms in planetary atmospheres

    NASA Astrophysics Data System (ADS)

    Hueso, R.; Sánchez-Lavega, A.

    2013-05-01

    The atmospheres of the planets in the Solar System have different physical properties that in some cases can be considered as extreme when compared with our own planet's more familiar atmosphere. From the tenuous and cold atmosphere of Mars to the dense and warm atmosphere of Venus in the case of the terrestrial planets, to the gigantic atmospheres of the outer planets, or the nitrogen and methane atmosphere of Saturn's moon Titan, we can find a large variety of physical environments. The comparative study of these atmospheres provides a better understanding of the physics of a geophysical fluid. In many of these worlds convective storms of different intensity appear. They are analogous to terrestrial atmospheres fed by the release of latent heat when one of the gases in the atmosphere condenses and they are therefore called moist convective storms. In many of these planets they can produce severe meteorological phenomena and by studying them in a comparative way we can aspire to get a further insight in the dynamics of these atmospheres even beyond the scope of moist convection. A classical example is the structure of the complex systems of winds in the giant planets Jupiter and Saturn. These winds are zonal and alternate in latitude but their deep structure is not accessible to direct observation. However the behaviour of large--scale convective storms vertically extending over the "weather layer" allows to study the buried roots of these winds. Another interesting atmosphere with a rather different structure of convection is Titan, a world where methane is close to its triple point in the atmosphere and can condense in bright clouds with large precipitation fluxes that may model part of the orography of the surface making Titan a world with a methane cycle similar to the hydrological cycle of Earth's atmosphere.

  2. Interactions Between Convective Storms and Their Environment

    NASA Technical Reports Server (NTRS)

    Maddox, R. A.; Hoxit, L. R.; Chappell, C. F.

    1979-01-01

    The ways in which intense convective storms interact with their environment are considered for a number of specific severe storm situations. A physical model of subcloud wind fields and vertical wind profiles was developed to explain the often observed intensification of convective storms that move along or across thermal boundaries. A number of special, unusually dense, data sets were used to substantiate features of the model. GOES imagery was used in conjunction with objectively analyzed surface wind data to develop a nowcast technique that might be used to identify specific storm cells likely to become tornadic. It was shown that circulations associated with organized meso-alpha and meso-beta scale storm complexes may, on occasion, strongly modify tropospheric thermodynamic patterns and flow fields.

  3. Water content in convective storm clouds.

    PubMed

    Kyle, T G; Sand, W R

    1973-06-22

    The condensed water content of convective storms was measured by the use of a penetrating aircraft. Regions 1 to 2 kilometers in extent and having condensed water contents of about 20 grams per cubic meter were found to be definite features of the cloud interior.

  4. Modelling Convective Dust Storms in Large-Scale Weather and Climate Models

    NASA Astrophysics Data System (ADS)

    Pantillon, Florian; Knippertz, Peter; Marsham, John H.; Panitz, Hans-Jürgen; Bischoff-Gauss, Ingeborg

    2016-04-01

    Recent field campaigns have shown that convective dust storms - also known as haboobs or cold pool outflows - contribute a significant fraction of dust uplift over the Sahara and Sahel in summer. However, in-situ observations are sparse and convective dust storms are frequently concealed by clouds in satellite imagery. Therefore numerical models are often the only available source of information over the area. Here a regional climate model with explicit representation of convection delivers the first full seasonal cycle of convective dust storms over North Africa. The model suggests that they contribute one fifth of the annual dust uplift over North Africa, one fourth between May and October, and one third over the western Sahel during this season. In contrast, most large-scale weather and climate models do not explicitly represent convection and thus lack such storms. A simple parameterization of convective dust storms has recently been developed, based on the downdraft mass flux of convection schemes. The parameterization is applied here to a set of regional climate runs with different horizontal resolutions and convection schemes, and assessed against the explicit run and against sparse station observations. The parameterization succeeds in capturing the geographical distribution and seasonal cycle of convective dust storms. It can be tuned to different horizontal resolutions and convection schemes, although the details of the geographical distribution and seasonal cycle depend on the representation of the monsoon in the parent model. Different versions of the parameterization are further discussed with respect to differences in the frequency of extreme events. The results show that the parameterization is reliable and can therefore solve a long-standing problem in simulating dust storms in large-scale weather and climate models.

  5. Modelling Convective Dust Storms in Large-Scale Weather and Climate Models

    NASA Astrophysics Data System (ADS)

    Pantillon, F.; Knippertz, P.; Marsham, J. H.; Panitz, H. J.; Bischoff-Gauss, I.

    2015-12-01

    Recent field campaigns have shown that convective dust storms - also known as haboobs or cold pool outflows - contribute a significant fraction of dust uplift over the Sahara and Sahel in summer. However, in-situ observations are sparse and convective dust storms are frequently concealed by clouds in satellite imagery. Therefore numerical models are often the only available source of information over the area. Here a regional climate model with explicit representation of convection delivers the first full seasonal cycle of convective dust storms over North Africa. The model suggests that they contribute one fifth of the annual dust uplift over North Africa, one fourth between May and October, and one third over the western Sahel during this season. In contrast, most large-scale weather and climate models do not explicitly represent convection and thus lack such storms.A simple parameterization of convective dust storms has recently been developed, based on the downdraft mass flux of convection schemes. The parameterization is applied here to a set of regional climate runs with different horizontal resolutions and convection schemes, and assessed against the explicit run and against sparse station observations. The parameterization succeeds in capturing the geographical distribution and seasonal cycle of convective dust storms. It can be tuned to different horizontal resolutions and convection schemes, although the details of the geographical distribution and seasonal cycle depend on the representation of the monsoon in the parent model. Different versions of the parameterization are further discussed with respect to differences in the frequency of extreme events. The results show that the parameterization is reliable and can therefore solve a long-standing problem in simulating dust storms in large-scale weather and climate models.

  6. On the relationships between convective storm kinematics, microphysics, and lightning

    NASA Astrophysics Data System (ADS)

    Lang, Timothy James

    Combined multiparameter radar, dual-Doppler, thermodynamic sounding, and lightning observations of 11 thunderstorms (6 from the mid-latitudes, 5 from the tropics) are presented. The thunderstorms span a wide spectrum of intensities, from weak monsoon-type to severe tornadic, and include both unicellular and multicellular convection. In general, the kinematically strongest storms featured lower production of negative cloud-to- ground lightning (typically <1 min-1 flash rates for large portions of the storms' lifetimes) when compared with more moderate convection, in accord with an elevated charge mechanism. The only significant differences between intense storms that produced predominately positive cloud-to-ground (CG) lightning for a significant portion of their lifetimes (PPCG storms), and intense storms that produced little CG lightning of any polarity (low-CG storms), was that PPCG storms featured much larger volumes of significant updrafts (both >10 m s-1 and >20 m s-1) and produced greater amounts of precipitation (both rain and hail). Otherwise, peak updrafts and vertical air mass fluxes were very similar between the two types of storms, and both types were linked by anomalously low production of negative CG lightning. It is suggested that PPCG storms may be caused by enhanced lower positive charge created by the larger volume of significant updrafts. Since both PPCG and low- CG storms are capable of being severe, anomalously low production of negative CG lightning (regardless of positive CG flash rate) may be a useful signature for use in the ``nowcasting'' of severe convection.

  7. 3D Simulations of methane convective storms on Titan's atmosphere

    NASA Astrophysics Data System (ADS)

    Hueso, R.; Sánchez-Lavega, A.

    2005-08-01

    The arrival of the Cassini/Huygens mission to Titan has opened an unprecedented opportunity to study the atmosphere of this satellite. Under the pressure-temperature conditions on Titan, methane, a large atmospheric component amounting perhaps to a 3-5% of the atmosphere, is close to its triple point, potentially playing a similar role as water on Earth. The Huygens probe has shown a terrain shaped by erosion of probably liquid origin, suggestive of past rain. On the other hand, Voyager IRIS spectroscopic observations of Titan imply a saturated atmosphere of methane (amounting perhaps to 150 covered by methane clouds, if we think on Earth meteorology. However, observations from Earth and Cassini have shown that clouds are localized, transient and fast evolving, in particular in the South Pole (currently in its summer season). This might imply a lack of widespread presence on Titan of nuclei where methane could initiate condensation and particle growth with subsequent precipitation. We investigate different scenarios of moist convective storms on Titan using a complete 3D atmospheric model that incorporates a full microphysics treatment required to study cloud formation processes under a saturated atmosphere with low concentration of condensation nuclei. We study local convective development under a variety of atmospheric conditions: sub-saturation, super-saturation, abundances of condensation nuclei fall, condensation nuclei lifted from the ground or gently falling from the stratosphere. We show that under the appropriate circumstances, precipitation rates comparable to typical tropical storms on Earth can be found. Acknowledgements: This work has been funded by Spanish MCYT PNAYA2003-03216, fondos FEDER and Grupos UPV 15946/2004. R. Hueso acknowledges a post-doc fellowship from Gobierno Vasco.

  8. Moist convective storms in the atmosphere of Saturn

    NASA Astrophysics Data System (ADS)

    Hueso, R.; Sánchez-Lavega, A.

    2003-05-01

    Moist convective storms might be a key aspect in the global energy budget of the atmospheres of the Giant Planets. In spite of its dull appearance, Saturn is known to develop the largest scale convective storms in the Solar System, the Great White Spots, the last of them arising in 1990 triggered a planetary scale disturbance that encircled the whole Equatorial region. However, Saturn seems to be very much less convective than Jupiter, being convective storms rare and small for the most part of the cases. Here we present simulations of moist convective storms in the atmosphere of Saturn at different latitudes, the Equator and 42 deg S, the regions where most of the convective activity of the planet has been observed. We use a 3D anelastic model of the atmosphere with parameterized microphysics (Hueso and Sánchez-Lavega, 2001) and we study the onset and evolution of moist convective storms. Ammonia storms are able to develop only if the static stability of the upper atmosphere is slightly decreased. Water storms are difficult to develop requiring very specific atmospheric conditions. However, when they develop they can be very energetic arriving at least to the 150 mbar level. The Coriolis forces play a mayor role in the characteristics of water based storms in the atmosphere of Saturn. The 3-D Coriolis forces at the Equator transfer upward momentum to westward motions acting to diminish the strength of the equatorial jet. The GWS of 1990 could have been a mayor force in reducing the intensity of the equatorial jet stream as revealed recently (Sánchez-Lavega et al. Nature, 2003). The Cassini spacecraft will arrive to Saturn in a year. Its observations of the atmosphere will allow to measure the amount of convective activity on the planet, its characteristics and it will clarify the role of moist convection in the atmospheric dynamics of the Giant Planets. Acknowledgements: This work was supported by the Spanish MCYT PNAYA 2000-0932. RH acknowledges a Post

  9. Severe local convective storms in Bangladesh: Part II.: Environmental conditions

    NASA Astrophysics Data System (ADS)

    Yamane, Yusuke; Hayashi, Taiichi; Dewan, Ashraf Mahmmood; Akter, Fatima

    2010-03-01

    This paper examines the environmental conditions of severe local convective storms during the pre-monsoon season (from March to May) in Bangladesh. We compared composite soundings on severe local convective storm days (SLCSD) with those on non-severe local convective storm days (NSLCSD) using rawinsonde data at 06 Bangladesh Standard Time (BST) in Dhaka (90.3°E and 23.7°N). Temperatures are rising in the lower layer and falling in the middle layer, and the amount of water vapor is significantly increasing in the lowest layer with southerly wind intensified on SLCSD compared with NSLCSD. This situation produces great thermal instability in the atmosphere on SLCSD. Convective parameters on SLCSD are computed with the rawinsonde data at 06 BST in Dhaka and compared with those on NSLCSD. The comparison shows that while most convective parameters related to thermal instability can discriminate between SLCSD and NSLCSD with statistical significance, no convective parameters related to the vertical wind shear can distinguish between the two categories. We evaluated the forecast skill of the convective parameters using Heidke Skill Score (HSS). The evaluation shows that the HSS for the Lifted Index and Precipitable Water are better among all parameters and have great forecast ability.

  10. Characteristics of Extreme Summer Convection over equatorial America and Africa

    NASA Astrophysics Data System (ADS)

    Zuluaga, M. D.; Houze, R.

    2013-12-01

    Fourteen years of Tropical Rainfall Measuring Mission (TRMM) Precipitation Radar (PR) version 7 data for June-August show the temporal and spatial characteristics of extreme convection over equatorial regions of the American and African continents. We identify three types of extreme systems: storms with deep convective cores (contiguous convective 40 dBZ echoes extending ≥10 km in height), storms with wide convective cores (contiguous convective 40 dBZ echoes with areas >1,000 km2) and storms with broad stratiform regions (stratiform echo >50,000 km2). European Centre for Medium-Range Weather Forecast (ECMWF) reanalysis is used to describe the environmental conditions around these forms of extreme convection. Storms with deep convective cores occur mainly over land: in the equatorial Americas, maximum occurrence is in western Mexico, Northern Colombia and Venezuela; in Africa, the region of maximum occurrence is a broad zone enclosing the central and west Sudanian Savanna, south of the Sahel region. Storms with wide convective radar echoes occur in these same general locations. In the American sector, storms with broad stratiform precipitation regions (typifying robust mesoscale convective systems) occur mainly over the eastern tropical Pacific Ocean and the Colombia-Panama bight. In the African sector, storms with broad stratiform precipitation areas occur primarily over the eastern tropical Atlantic Ocean near the coast of West Africa. ECMWF reanalyses show how the regions of extreme deep convection associated with both continents are located mainly in regions affected by diurnal heating and influenced by atmospheric jets in regions with strong humidity gradients. Composite analysis of the synoptic conditions leading to the three forms of extreme convection provides insights into the forcing mechanisms in which these systems occur. These analyses show how the monsoonal flow directed towards the Andes slopes is mainly what concentrates the occurrence of extreme

  11. A-Train Observations of Deep Convective Storm Tops

    NASA Technical Reports Server (NTRS)

    Setvak, Martin; Bedka, Kristopher; Lindsey, Daniel T.; Sokol, Alois; Charvat, Zdenek; Stastka, Jindrich; Wang, Pao K.

    2013-01-01

    The paper highlights simultaneous observations of tops of deep convective clouds from several space-borne instruments including the Moderate Resolution Imaging Spectroradiometer (MODIS) of the Aqua satellite, Cloud Profiling Radar (CPR) of the CloudSat satellite, and Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) flown on the CALIPSO satellite. These satellites share very close orbits, thus together with several other satellites they are referred to as the "A-Train" constellation. Though the primary responsibility of these satellites and their instrumentation is much broader than observations of fine-scale processes atop convective storms, in this study we document how data from the A-Train can contribute to a better understanding and interpretation of various storm-top features, such as overshooting tops, cold-U/V and cold ring features with their coupled embedded warm areas, above anvil ice plumes and jumping cirrus. The relationships between MODIS multi-spectral brightness temperature difference (BTD) fields and cloud top signatures observed by the CPR and CALIOP are also examined in detail to highlight the variability in BTD signals across convective storm events.

  12. Modes of isolated, severe convective storm formation along the dryline

    SciTech Connect

    Bluestein, H.B.; Parker, S.S. )

    1993-05-01

    Patterns of the formation of isolated, severe convective storms along the dryline in the Southern plains of the United States during the spring over a 16-year period were determined from an examination of the evolution of radar echoes as depicted by WSR-57 microfilm data. It was found that in the first 30 min after the first echo, more than half of the radar echoes evolved into isolated storms as isolated cells from the start; others developed either from a pair of cells, from a line segment, from a cluster of cells, from the merger of mature cells, or from a squall line. Proximity soundings were constructed from both standard and special soundings, and from standard surface data. It was found that the estimated convective available potential energy and vertical shear are characteristic of the environment of supercell storms. The average time lag between the first echo and the first occurrence of severe weather of any type, or tornadoes alone, was approximately 2 h. There were no significant differences in the environmental parameters for the different modes of storm formation. 49 refs., 15 figs., 3 tabs.

  13. Particle Energization During Magnetic Storms with Steady Magnetospheric Convection

    NASA Astrophysics Data System (ADS)

    Kissinger, J.; Kepko, L.; Baker, D. N.; Kanekal, S. G.; Li, W.; McPherron, R. L.; Angelopoulos, V.

    2013-12-01

    Relativistic electrons pose a space weather hazard to satellites in the radiation belts. Although about half of all geomagnetic storms result in relativistic electron flux enhancements, other storms decrease relativistic electron flux, even under similar solar wind drivers. Radiation belt fluxes depend on a complex balance between transport, loss, and acceleration. A critically important aspect of radiation belt enhancements is the role of the 'seed' population--plasma sheet particles heated and transported Earthward by magnetotail processes--which can become accelerated by wave-particle interactions with chorus waves. While the effect of substorms on seed electron injections has received considerable focus, in this study we explore how quasi-steady convection during steady magnetospheric convection (SMC) events affects the transport and energization of electrons. SMC events are long-duration intervals of enhanced convection without any substorm expansions, and are an important mechanism in coupling magnetotail plasma populations to the inner magnetosphere. We detail the behavior of the seed electron population for stormtime SMC events using the Van Allen Probes in the outer radiation belt and THEMIS in the plasma sheet and inner magnetosphere. Together, the two missions provide the ability to track particle transport and energization from the plasma sheet into the radiation belts. We present SMC events with Van Allen Probes/THEMIS conjunctions and compare plasma sheet fast flows/enhanced transport to radiation belt seed electron enhancements. Finally we utilize statistical analyses to quantify the relative importance of SMC events on radiation belt electron acceleration in comparison to isolated substorms.

  14. Spatial and diurnal variations of storm heights in the East Asia summer monsoon: storm height regimes and large-scale diurnal modulation

    NASA Astrophysics Data System (ADS)

    Park, Myung-Sook; Lee, Myong-In; Kim, Hyerim; Im, Jungho; Yoo, Jung-Moon

    2016-02-01

    This study investigates the spatial and diurnal variation of storm height in the East Asia summer monsoon region using 13-year Tropical Rainfall Measuring Mission Precipitation Radar data. Precipitating storms are classified as shallow (<5 km), middle (5-10 km), and deep (>10 km) depending the height. Four different regimes are identified to characterize the region: the continental (CT) shallow regime over inland China with elevated terrain, the CT deep over the Chinese Plain, the coastal (CS) middle over the East China Sea and South Sea of Korea, and the CS shallow over the south coastal area of Japan. This regime separation reflects well the distinctive regional difference in the rainfall contribution by each storm type. The occurrence frequencies of shallow, middle, and deep storms exhibit pronounced diurnal variation as well, but with significant differences in the amplitude and phase across the regimes. These lead to a diversity in the diurnal variation of surface rainfall such as bimodal morning and late evening peaks in the two CT regimes and the single morning peak in the two CS regimes. Processes involved in the diurnal variation of storms are different across the regimes, indicating difference in the contributing role of surface heating, large-scale diurnal circulation, and diurnal propagations of convective systems. The storm height also affects the rain intensity. This study highlights that the East Asia summer monsoon has distinctive sub-regional variation of the storm height distribution, thereby providing unique differences in the rainfall amount, intensity, and the diurnal variation.

  15. Summer rainfall over the southwestern Tibetan Plateau controlled by deep convection over the Indian subcontinent.

    PubMed

    Dong, Wenhao; Lin, Yanluan; Wright, Jonathon S; Ming, Yi; Xie, Yuanyu; Wang, Bin; Luo, Yong; Huang, Wenyu; Huang, Jianbin; Wang, Lei; Tian, Lide; Peng, Yiran; Xu, Fanghua

    2016-03-07

    Despite the importance of precipitation and moisture transport over the Tibetan Plateau for glacier mass balance, river runoff and local ecology, changes in these quantities remain highly uncertain and poorly understood. Here we use observational data and model simulations to explore the close relationship between summer rainfall variability over the southwestern Tibetan Plateau (SWTP) and that over central-eastern India (CEI), which exists despite the separation of these two regions by the Himalayas. We show that this relationship is maintained primarily by 'up-and-over' moisture transport, in which hydrometeors and moisture are lifted by convective storms over CEI and the Himalayan foothills and then swept over the SWTP by the mid-tropospheric circulation, rather than by upslope flow over the Himalayas. Sensitivity simulations confirm the importance of up-and-over transport at event scales, and an objective storm classification indicates that this pathway accounts for approximately half of total summer rainfall over the SWTP.

  16. Summer rainfall over the southwestern Tibetan Plateau controlled by deep convection over the Indian subcontinent.

    PubMed

    Dong, Wenhao; Lin, Yanluan; Wright, Jonathon S; Ming, Yi; Xie, Yuanyu; Wang, Bin; Luo, Yong; Huang, Wenyu; Huang, Jianbin; Wang, Lei; Tian, Lide; Peng, Yiran; Xu, Fanghua

    2016-01-01

    Despite the importance of precipitation and moisture transport over the Tibetan Plateau for glacier mass balance, river runoff and local ecology, changes in these quantities remain highly uncertain and poorly understood. Here we use observational data and model simulations to explore the close relationship between summer rainfall variability over the southwestern Tibetan Plateau (SWTP) and that over central-eastern India (CEI), which exists despite the separation of these two regions by the Himalayas. We show that this relationship is maintained primarily by 'up-and-over' moisture transport, in which hydrometeors and moisture are lifted by convective storms over CEI and the Himalayan foothills and then swept over the SWTP by the mid-tropospheric circulation, rather than by upslope flow over the Himalayas. Sensitivity simulations confirm the importance of up-and-over transport at event scales, and an objective storm classification indicates that this pathway accounts for approximately half of total summer rainfall over the SWTP. PMID:26948491

  17. Summer rainfall over the southwestern Tibetan Plateau controlled by deep convection over the Indian subcontinent

    PubMed Central

    Dong, Wenhao; Lin, Yanluan; Wright, Jonathon S.; Ming, Yi; Xie, Yuanyu; Wang, Bin; Luo, Yong; Huang, Wenyu; Huang, Jianbin; Wang, Lei; Tian, Lide; Peng, Yiran; Xu, Fanghua

    2016-01-01

    Despite the importance of precipitation and moisture transport over the Tibetan Plateau for glacier mass balance, river runoff and local ecology, changes in these quantities remain highly uncertain and poorly understood. Here we use observational data and model simulations to explore the close relationship between summer rainfall variability over the southwestern Tibetan Plateau (SWTP) and that over central-eastern India (CEI), which exists despite the separation of these two regions by the Himalayas. We show that this relationship is maintained primarily by ‘up-and-over' moisture transport, in which hydrometeors and moisture are lifted by convective storms over CEI and the Himalayan foothills and then swept over the SWTP by the mid-tropospheric circulation, rather than by upslope flow over the Himalayas. Sensitivity simulations confirm the importance of up-and-over transport at event scales, and an objective storm classification indicates that this pathway accounts for approximately half of total summer rainfall over the SWTP. PMID:26948491

  18. Empirical reconstruction of storm-time steady magnetospheric convection events

    NASA Astrophysics Data System (ADS)

    Stephens, G. K.; Sitnov, M. I.; Kissinger, J.; Tsyganenko, N. A.; McPherron, R. L.; Korth, H.; Anderson, B. J.

    2013-12-01

    We investigate the storm-scale morphology of the magnetospheric magnetic field as well as underlying distributions of electric currents, equatorial plasma pressure and entropy for four Steady Magnetospheric Convection (SMC) events that occurred during the May 2000 and October 2011 magnetic storms. The analysis is made using the empirical geomagnetic field model TS07D, in which the structure of equatorial currents is not predefined and it is dictated by data. The model also combines the strengths of statistical and event-oriented approaches in mining data for the reconstruction of the magnetic field. The formation of a near-Earth minimum of the equatorial magnetic field in the midnight sector is inferred from data without ad hoc assumptions of a special current system postulated in earlier empirical reconstructions. In addition, a new SMC class is discovered where the minimum equatorial field is substantially larger and located closer to Earth. The magnetic field tailward of the minimum is also much larger, and the corresponding region of accumulated magnetic flux may occupy a very short tail region. The equatorial current and plasma pressure are found to be strongly enhanced far beyond geosynchronous orbit and in a broad local time interval covering the whole nightside region. This picture is consistent with independent recent statistical studies of the SMC pressure distributions, global MHD and kinetic RCM-E simulations. Distributions of the flux tube volume and entropy inferred from data reveal different mechanisms of the magnetotail convection crisis resolution for two classes of SMC events.

  19. A three-dimensional model of moist convection for the giant planets II: Saturn's water and ammonia moist convective storms

    NASA Astrophysics Data System (ADS)

    Hueso, Ricardo; Sánchez-Lavega, Agustín

    2004-11-01

    Moist convective storms constitute a key aspect in the global energy budget of the atmospheres of the giant planets. Among them, Saturn is known to develop the largest scale convective storms in the Solar System, the Great White Spots (GWS) which occur rarely and have been detected once every 30 years approximately. On the average, Saturn seems to show much less convective storms than Jupiter with smaller size and reduced frequency and intensity. Here we present detailed simulations of the onset and development of storms at the Equator and mid-latitudes of Saturn. These are the regions where most of the recent convective activity of the planet has been observed. We use a 3D anelastic model with parameterized microphysics (Hueso and Sánchez-Lavega, 2001, Icarus 151, 257) studying the onset and evolution of water and ammonia moist convective storms up to sizes of a few hundred km. Water storms, while more difficult to initiate than in Jupiter, can be very energetic, arriving to the 150 mbar level and developing vertical velocities on the order of 150 m s -1. Ammonia storms develop easier but with a much smaller intensity unless very large abundances of ammonia (10 times solar) are present in Saturn's atmosphere. The Coriolis forces play a major role in the morphology and properties of water based storms.

  20. The Importance of the Vertical Location of Aerosol Layers on Convective Storms

    NASA Astrophysics Data System (ADS)

    van den Heever, Susan; Grant, Leah

    2014-05-01

    Enhanced aerosol concentrations appear to influence a number of the aspects of convective storms including the strength of the convective updraft, the intensity of the cold pool, and the microphysical and radiative characteristics of the convective anvil. However, in order for such influences to occur, aerosols need to be effectively ingested by the storm system of interest. The vertical location of an aerosol layer impacting a convective storm may influence how effectively aerosol are ingested by the storm system, and hence the degree to which the ingested aerosol subsequently influence storm microphysical and radiative processes. Furthermore, if the aerosol species impacting the storm are effective at absorbing solar radiation, heating within the aerosol layer enhances atmospheric stability, the level of which will be dictated by where the aerosol layer is located. Enhanced static stability may have negative impacts on the initial development of the convection of interest. Convective storms developing within environments of the same aerosol optical depth may therefore respond differently to aerosol indirect forcing by virtue of where the aerosol layer is vertically located. In this talk, the results of various high-resolution, cloud-resolving simulations will be presented, in which the sensitivity to the vertical location of the aerosol source on the convective development, aerosol ingestion efficiency, and subsequent microphysical and radiative properties are investigated. Microphysical budgets and storm trajectories will form an integral part of the analysis.

  1. Evidence for Gravity Wave Seeding of Convective Ionosphere Storms Initiated by Deep Troposphere Convection

    NASA Astrophysics Data System (ADS)

    Kelley, M. C.; Pfaff, R. F., Jr.; Dao, E. V.; Holzworth, R. H., II

    2014-12-01

    With the increase in solar activity, the Communications/Outage Forecast System satellite (C/NOFS) now goes below the F peak. As such, we now can study the development of Convective Ionospheric Storms (CIS) and, most importantly, large-scale seeding of the low growth-rate Rayleigh-Taylor (R-T) instability. Two mechanisms have been suggested for such seeding: the Collisional Kelvin-Helmholtz Instability (CKHI) and internal atmospheric gravity waves. A number of observations have shown that the spectrum of fully developed topside structures peaks at 600 km and extends to over 1000 km. These structures are exceedingly difficult to explain by CKHI. Here we show that sinusoidal plasma oscillations on the bottomside during daytime develop classical R-T structures on the nightside with the background 600 km structure still apparent. In two case studies, thunderstorm activity was observed east of the sinusoidal features in the two hours preceding the C/NOFS passes. Thus, we argue that convective tropospheric storms are a likely source of these sinusoidal features.

  2. Changes in concentration of Alternaria and Cladosporium spores during summer storms.

    PubMed

    Grinn-Gofroń, Agnieszka; Strzelczak, Agnieszka

    2013-09-01

    Fungal spores are known to cause allergic sensitization. Recent studies reported a strong association between asthma symptoms and thunderstorms that could be explained by an increase in airborne fungal spore concentrations. Just before and during thunderstorms the values of meteorological parameters rapidly change. Therefore, the goal of this study was to create a predictive model for hourly concentrations of atmospheric Alternaria and Cladosporium spores on days with summer storms in Szczecin (Poland) based on meteorological conditions. For this study we have chosen all days of June, July and August (2004-2009) with convective thunderstorms. There were statistically significant relationships between spore concentration and meteorological parameters: positive for air temperature and ozone content while negative for relative humidity. In general, before a thunderstorm, air temperature and ozone concentration increased, which was accompanied by a considerable increase in spore concentration. During and after a storm, relative humidity increased while both air temperature ozone concentration along with spore concentrations decreased. Artificial neural networks (ANN) were used to assess forecasting possibilities. Good performance of ANN models in this study suggest that it is possible to predict spore concentrations from meteorological variables 2 h in advance and, thus, warn people with spore-related asthma symptoms about the increasing abundance of airborne fungi on days with storms. PMID:23161270

  3. Changes in concentration of Alternaria and Cladosporium spores during summer storms.

    PubMed

    Grinn-Gofroń, Agnieszka; Strzelczak, Agnieszka

    2013-09-01

    Fungal spores are known to cause allergic sensitization. Recent studies reported a strong association between asthma symptoms and thunderstorms that could be explained by an increase in airborne fungal spore concentrations. Just before and during thunderstorms the values of meteorological parameters rapidly change. Therefore, the goal of this study was to create a predictive model for hourly concentrations of atmospheric Alternaria and Cladosporium spores on days with summer storms in Szczecin (Poland) based on meteorological conditions. For this study we have chosen all days of June, July and August (2004-2009) with convective thunderstorms. There were statistically significant relationships between spore concentration and meteorological parameters: positive for air temperature and ozone content while negative for relative humidity. In general, before a thunderstorm, air temperature and ozone concentration increased, which was accompanied by a considerable increase in spore concentration. During and after a storm, relative humidity increased while both air temperature ozone concentration along with spore concentrations decreased. Artificial neural networks (ANN) were used to assess forecasting possibilities. Good performance of ANN models in this study suggest that it is possible to predict spore concentrations from meteorological variables 2 h in advance and, thus, warn people with spore-related asthma symptoms about the increasing abundance of airborne fungi on days with storms.

  4. Changes in concentration of Alternaria and Cladosporium spores during summer storms

    NASA Astrophysics Data System (ADS)

    Grinn-Gofroń, Agnieszka; Strzelczak, Agnieszka

    2013-09-01

    Fungal spores are known to cause allergic sensitization. Recent studies reported a strong association between asthma symptoms and thunderstorms that could be explained by an increase in airborne fungal spore concentrations. Just before and during thunderstorms the values of meteorological parameters rapidly change. Therefore, the goal of this study was to create a predictive model for hourly concentrations of atmospheric Alternaria and Cladosporium spores on days with summer storms in Szczecin (Poland) based on meteorological conditions. For this study we have chosen all days of June, July and August (2004-2009) with convective thunderstorms. There were statistically significant relationships between spore concentration and meteorological parameters: positive for air temperature and ozone content while negative for relative humidity. In general, before a thunderstorm, air temperature and ozone concentration increased, which was accompanied by a considerable increase in spore concentration. During and after a storm, relative humidity increased while both air temperature ozone concentration along with spore concentrations decreased. Artificial neural networks (ANN) were used to assess forecasting possibilities. Good performance of ANN models in this study suggest that it is possible to predict spore concentrations from meteorological variables 2 h in advance and, thus, warn people with spore-related asthma symptoms about the increasing abundance of airborne fungi on days with storms.

  5. Remote sensing of severe convective storms over Qinghai-Xizang Plateau

    NASA Technical Reports Server (NTRS)

    Hung, R. J.; Liu, J. M.; Tsao, D. Y.; Smith, R. E.

    1984-01-01

    The American satellite, GOES-1 was moved to the Indian Ocean at 58 deg E during the First GARP Global Experiment (FGGE). The Qinghai-Xizang Plateau significantly affects the initiation and development of heavy rainfall and severe storms in China, just as the Rocky Mountains influence the local storms in the United States. Satelite remote sensing of short-lived, meso-scale convective storms is particularly important for covering a huge area of a high elevation with a low population density, such as the Qinghai-Xizang Plateau. Results of this study show that a high growth rate of the convective clouds, followed by a rapid collapse of the cloud top, is associated with heavy rainfall in the area. The tops of the convective clouds developed over the Plateau lie between the altitudes of the two tropopauses, while the tops of convective clouds associated with severe storms in the United States usually extend much above the tropopause.

  6. Dependency of the North Pacific winter storm tracks on the zonal distribution of MJO convection

    NASA Astrophysics Data System (ADS)

    Lee, Yun-Young; Lim, Gyu-Ho

    2012-07-01

    We investigate the effects of the tropical Madden Julian Oscillation (MJO) convection on the zonal location and intensity of storm activity during the boreal cool season (Nov. 1 to Feb. 28, 120 days) over the Pacific Ocean. As tropical convection shifts eastward from the eastern Indian Ocean to the western North Pacific, MJO-induced local Hadley circulation leads to an eastward displacement of extratropical Rossby Wave Source (RWS). Consequently, this influence leads to an eastward shift of the peak area of the storm track. The storm track is strongest with the MJO convection over the eastern Indian Ocean (phase 3), and it experiences the suppression when MJO convection is located over the Maritime continents (phase 4), and it increases again when the MJO propagates to the western Pacific (phase 5), after which it weakens again (phase 6). The intensity of the storm track, particularly over the western North Pacific (120°E-180°), is determined by the integrated effects of three factors: the midlatitude convective forcing (MCF), the jet stream, and RWS. These factors are associated with the locations of MJO convections. It is estimated that MJO-induced suppression accounts for only 2.5% of the total observed midwinter suppression (MWS). However, the pattern generated by the MJO is remarkably similar to the observed meridional displacement of North Pacific storm track associated with sub-seasonal variation. We conclude that the spatial distribution of MJO affects the variation of the Pacific storm track, but is not a cause of the MWS.

  7. Convective rain rates and their evolution during storms in a semiarid climate

    NASA Technical Reports Server (NTRS)

    Doneaud, A. A.; Miller, J. R., Jr.; Ionescu-Niscov, S.

    1984-01-01

    The semiarid climate of the U.S. northern High Plains region has been studied with respect to rain rates and their evolution during summertime convective storms, using radar data from a total of 750 radar echo clusters. Analysis of this data suggests that the average rain rate R among storms is in a first approximation independent of the total rain volume, if the entire storm duration is considered in the averaging process. R primarily depends on the reflectivity threshold considered in calculating the area coverage integrated over the lifetime of the storm. R evolution during storms is analyzed by dividing each storm lifetime into 10 min, 1, 2, and 4 hours, as well as growing and decaying periods. The value of R remained independent of the total rain volume when the growing or decaying periods of storms were considered separately.

  8. Initialization of a modeled convective storm using Doppler radar-derived fields

    NASA Technical Reports Server (NTRS)

    Lin, Ying; Ray, Peter S.; Johnson, Kenneth W.

    1993-01-01

    A method is developed to initialize convective storm simulations with Doppler radar-derived fields. Input fields for initialization include velocity, rainwater derived from radar reflectivity, and pressure and temperature fields obtained through thermodynamic retrieval. A procedure has been developed to fill in missing wind data, followed by a variational adjustment to the filled wind field to minimize 'shocks' that would otherwise cause the simulated fields to deteriorate rapidly. A series of experiments using data from a simulated storm establishes the feasibility of the initialization method. Multiple-Doppler radar observations from the 20 May 1977 Del City tornadic storm are used for the initialization experiments. Simulation results are shown and compared to observations taken at a later time. The simulated storm shows good agreement with the subsequent observations, though the simulated storm appears to be evolving faster than observed. Possible reasons for the discrepancies are discussed.

  9. Links Between the Madden-Julian Oscillation and Severe Convective Storms in the U.S.

    NASA Astrophysics Data System (ADS)

    Barrett, B.

    2015-12-01

    Recent research has shown a tendency for severe convective storms to vary intraseasonally, including by phase of the Madden-Julian Oscillation (MJO). The MJO is the leading mode of atmospheric intraseasonal variability and is characterized by large regions (1000-5000 km) of anomalous convective activity that generally propagate eastward along the equator. Anomalous upper-troposphere heating associated with this convection generates poleward-propagating Rossby waves that interact with the preexisting extratropical circulation. The projection of this interaction onto the synoptic scale - via the favoring of troughs and ridges at certain positions - is the hypothesized mechanism by which the MJO modulates severe convection. However, one unexplored aspect of this modulation is the extent to which severe convection in winter and early-spring months, especially Jan-Mar, may be influenced by different phases of the MJO. While climatologically rarer than events later in spring, severe thunderstorms in winter and early spring still have potential to be high-impact weather events, especially as they often occur in populated areas of the southeast U.S. that have shown more vulnerability than other regions such as the southern or central plains. Results from other studies (not necessarily focused on the question of severe convective storms) have indicated statistically significant modulation of upper- and mid-tropospheric circulation (from 200 hPa to 700 hPa), surface temperature, and sea level pressure. Thus, it is possible that the MJO's influence also extends to severe storms, as these are ingredients known to affect the likelihood of convective activity in the U.S. Using a methodology similar to other recent MJO studies, the impacts of the MJO on tornado, hail, and wind activity from Jan-Mar will be tested as part of this larger project to understand intraseasonal variability of severe storms.

  10. Spatial characteristics of observed precipitation fields: A catalog of summer storms in Arizona, Volume 2

    NASA Technical Reports Server (NTRS)

    Fennessey, N. M.; Eagleson, P. S.; Qinliang, W.; Rodriguez-Iturbe, I.

    1986-01-01

    The parameters of the conceptual model are evaluated from the analysis of eight years of summer rainstorm data from the dense raingage network in the Walnut Gulch catchment near Tucson, Arizona. The occurrence of measurable rain at any one of the 93 gages during a noon to noon day defined a storm. The total rainfall at each of the gages during a storm day constituted the data set for a single storm. The data are interpolated onto a fine grid and analyzed to obtain: an isohyetal plot at 2 mm intervals, the first three moments of point storm depth, the spatial correlation function, the spatial variance function, and the spatial distribution of the total storm depth. The description of the data analysis and the computer programs necessary to read the associated data tapes are presented.

  11. Tests of Convection Electric Field Models For The January 10, 1997, Geomagnetic Storm

    NASA Astrophysics Data System (ADS)

    Jordanova, V.; Boonsiriseth, A.; Thorne, R.; Dotan, Y.

    The January 10-11, 1997, geomagnetic storm was caused by the passage at Earth of a magnetic cloud with a negative to positive Bz variation extending for 1 day. The ge- omagnetic indices had values of minimum Dst=-83 nT and maximum Kp=6 during the period of southward IMF within the cloud. We simulate ring current development during this storm using our kinetic drift-loss model and compare the results inferred from Volland-Stern type, Weimer, and AMIE convection electric field models. A pen- etration electric field is added to the AMIE model [Boonsiriseth et al., 2001] in order to improve the agreement with measurements from the electric field instrument on Po- lar spacecraft. The ionospheric electric potentials are mapped to the equatorial plane using the Tsyganenko 1996 magnetic field model and the resulting equatorial poten- tial models are coupled with our ring current model. While the temporal evolution of the large-scale features is similar in all three convection models, detailed comparison indicates that AMIE model shows highly variable small-scale features not present in the Volland-Stern or Weimer convection models. Results from our kinetic ring current model are compared with energetic particle data from the HYDRA, TIMAS, IPS, and CAMMICE instruments on Polar to test the applicability of the convection electric field models for this storm period.

  12. Sensitivity of the Amazon rainforest to convective storms

    NASA Astrophysics Data System (ADS)

    Negron Juarez, R. I.; Chambers, J. Q.; Rifai, S. W.; Urquiza Munoz, J. D.; Tello, R.; Alegria Munoz, W.; Marra, D.; Ribeiro, G.; Higuchi, N.

    2012-12-01

    The Amazon rainforest is the largest contiguous continental tropical forest in the world and is a world center of carbon storage, biodiversity, biogeochemical cycles and biogeophysical processes that affect the Earth climate system. Yet anthropogenic activities have produced changes in the forest-climate system. Consequently, an increase in rainfall in both the Western and Central Amazon and a decrease in the Eastern Amazon are expected due to these anthropogenic activities. While the projected decrease in rainfall has been discussed under the context of drought, deforestation, and fires, the effect of an increase in rainfall, and associated convective processes, on forest ecosystems has been overlooked. Across the Amazon rainforest, Western Amazonia has the highest precipitation rates, wood productivity, soil fertility, recruitment and mortality rates. Yet our field-measured tree mortality data from blowdowns that occurred in Western and Central Amazonia do not show a statistical difference in tree mortality between these regions. However, downburst velocities associated with these disturbances were calculated to be lower in Western Amazonia than in the Central Amazon. This suggests the Western Amazon is more highly sensitive to intense convective systems. This result is particularly relevant given the expected increase in rainfall in the Western and Central Amazon. The increase in rainfall is associated with more intense convective systems that in turn imply an increase in low level jet stream (LLJ) intensity east of the Andes. The presence of the LLJ is the main cause of squall lines and an increase in LLJ intensity will therefore cause increased propagation of squall lines into the Amazon basin. More frequent and active squall lines have the potential to increase the intensity and frequency of downbursts responsible for large forest blowdowns that will affect the biogeophysical feedbacks on the forest ecosystem and carbon budget.

  13. Observations of lightning in convective supercells within tropical storms and hurricanes

    NASA Technical Reports Server (NTRS)

    Lyons, Walter A.; Keen, Cecil S.

    1994-01-01

    Cloud-to-ground (CG) lightning observations from land-based lightning detection networks now allow monitoring this component of the electrical structure of tropical storms and hurricanes within a few hundred kilometers of the United States coastline. Several case studies confirm the long-held opinion that lightning is rather common within the outer rainbands. The general absence of CG lightning within the interior of mature tropical cyclones is also apparent. On the other hand, bursts of CG lightning near the circulation center of developing storms appear to precede periods of further deepening. The CG events are associated with convective supercells, whose anvil canopies can often obscure much of the underlying storm. Near-eyewall CG bursts preceding periods of intensification were noted in Hurricanes Diana (1984) and Florence (1988). A detailed case study of the 1987 unnamed tropical storm that struck the Texas-Louisiana coastline reveals that lightning was associated with two large supercells. These supercells appeared to be the trigger for the development of a closed circulation that formed several hours after the apparent low pressure center made landfall. Further studies of lightning may provide additional insight into the role of convective supercells in tropical storm intensification. It may also provide a useful diagnostic of impending deepening.

  14. Observations of lightning in convective supercells within tropical storms and hurricanes

    SciTech Connect

    Lyons, W.A.; Keen, C.S. |

    1994-08-01

    Cloud-to-ground (CG) lightning observations from land-based lightning detection networks now allow monitoring this component of the electrical structure of tropical storms and hurricanes within a few hundred kilometers of the United States coastline. Several case studies confirm the long-held opinion that lightning is rather common within the outer rainbands. The general absence of CG lightning within the interior of mature tropical cyclones is also apparent. On the other hand, bursts of CG lightning near the circulation center of developing storms appear to precede periods of further deepening. The CG events are associated with convective supercells, whose anvil canopies can often obscure much of the underlying storm. Near-eyewall CG bursts preceding periods of intensification were noted in Hurricanes Diana (1984) and Florence (1988). A detailed case study of the 1987 unnamed tropical storm that struck the Texas-Louisiana coastline reveals that lightning was associated with two large supercells. These supercells appeared to be the trigger for the development of a closed circulation that formed several hours after the apparent low pressure center made landfall. Further studies of lightning may provide additional insight into the role of convective supercells in tropical storm intensification. It may also provide a useful diagnostic of impending deepening.

  15. Moist convection in hydrogen atmospheres and the frequency of Saturn's giant storms

    NASA Astrophysics Data System (ADS)

    Li, C.; Ingersoll, A. P.

    2015-12-01

    A giant planet-encircling storm occurred on Saturn on Dec. 5th, 2010 at planetographic latitude 37.7 N. It produced intense lightning, created enormous cloud disturbances and wrapped around the planet in 6 months. Six such storms, called Great White Spots, have erupted since 1876. They have alternated between mid-latitudes and the equator at intervals ranging from 20 to 30 years. The reason for the intermittent explosion is not clear and there are no similar storms on brother Jupiter. Here we describe the water-loading mechanism, which could suppress moist convection for decades due to the larger molecular weight of water in a hydrogen-helium atmosphere. We show that this mechanism requires the deep water vapor mixing ratio to be greater than 1.0%, which implies O/H at least 10 times the solar value. Observations imply that Saturn's atmosphere is more enriched in water than Jupiter, which could explain why Saturn has such storms and Jupiter does not. We further use a two-dimensional axisymmetric dynamic model and a top-cooling convective adjustment scheme to connect our theory to observation. We show that for a deep water vapor mixing ratio of 1.1%, the ammonia vapor is depleted down to 6 bars, the tropospheric warming is ~6 K, and the interval between two consecutive storms at one latitude is ~70 years. These values are consistent with observations.

  16. Evolution of conserved variables related to storm cells during severe convection in a mesoscale model

    NASA Astrophysics Data System (ADS)

    Weijenborg, Chris; Chagnon, Jeffrey; Friederichs, Petra; Gray, Suzanne; Hense, Andreas

    2014-05-01

    The WEX-MOP project aims at a next generation ensemble prediction system for the mesoscale. One goal of WEX-MOP is to quantify the role of conserved quantities during extreme convective weather. Conserved variables might offer new insight in the predictability of those events. An important conserved quantity is potential vorticity (PV), a fundamental property of the atmospheric flow on synoptic and planetary scales. However, investigations thereof on the atmospheric mesoscale are relatively new. PV has a close relation to rotation and balance, which is important in storm dynamics. Here we characterize the evolution of storm cells in terms of PV to provide new insights into storm dynamics. Tracking of storm cells has been frequently performed using radar and/or satellite data. It received less attention using model data. We present storm cell tracks for two cases of severe convection in June 2011 simulated using the non hydrostatic COSMO-DE weather model. The two cases have a very different background: on 5 June 2011 the convection was primarily locally forced by CAPE, while on 22 June there was strong forcing due to a cold front. For each of the two cases vertical velocity maxima are tracked. High intensity cells in both cases show a high correlation between PV and vertical velocity anomalies. This has been attributed to a strong environment storm relative helicity and/or CAPE close to the surface. For both cases there is a high variability in the cell characteristics. However, the PV anomalies on 22 June are larger than those on 5 June and have a higher correlation between vertical velocity and PV, consistent with the larger wind shear and helicity in the environment at this day. Study of further cases is necessary to test the hypothesis that a high helicity environment leads to more intense long lasting cells.

  17. Simulating supercell thunderstorms in a convective boundary layer: Effects on storm and boundary layer properties

    NASA Astrophysics Data System (ADS)

    Nowotarski, Christopher J.

    Nearly all previous numerical simulations of supercell thunderstorms have neglected surface uxes of heat, moisture, and momentum as well as horizontal inhomogeneities in the near-storm environment from resulting dry boundary layer convection. This investigation uses coupled radiation and land-surface schemes within an idealized cloud model to identify the effects of organized boundary layer convection in the form of horizontal convective rolls (HCRs) on the strength, structure, and evolution of simulated supercell thunderstorms. The in uence of HCRs and the importance of their orientation relative to storm motion is tested by comparing simulations with a convective boundary layer (CBL) against those with a horizontally homogeneous base state having the same mean environment. The impact of anvil shading on the CBL is tested by comparing simulations with and without the effects of clouds in the radiative transfer scheme. The results of these simulations indicate that HCRs provide a potentially important source of environmental vertical vorticity in the sheared, near-storm boundary layer. These vorticity perturbations are amplified both beneath the main supercell updraft and along the trailing out ow boundary, leading to the formation of occasionally intense misovortices. HCRs perpendicular to storm motion are found to have a detrimental effect on the strength and persistence of the lowlevel mesocyclone, particularly during its initial development. Though the mean environment is less supportive of low-level rotation with a wind profile conducive to HCRs oriented parallel to storm motion, such HCRs are found to often enhance the low-level mesocyclone circulation. When anvil shading is included, stabilization results in generally weaker low-level mesocyclone circulation, regardless of HCR orientation. Moreover, HCRs diminish in the near-storm environment such that the effects of HCRs on the supercell are mitigated. HCRs are also shown to be a necessary condition for the

  18. Joint analysis of multiparameter radar and radiometer measurements of convective storms

    NASA Technical Reports Server (NTRS)

    Vivekanandan, J.; Turk, J.; Stephens, G. L.

    1989-01-01

    An account is given of the radiative properties of hydrometeors in order to evaluate the influences of water, ice, and melting layers on the upwelling microwave radiances of convective storms. Attention is given to storm overflights conducted by the ER-2 aircraft in coordination with the NCAR dual-polarization/dual-wavelength mode radar. Radar-radiometer comparisons are conducted for one overflight from each day of the study campaign, using the various multiparameter radar observations to delineate regions of water, ice, and melting, as well as to obtain raindrop-size distribution. Model-computed brightness temperatures are compared with the ER-2 aircraft measurements.

  19. Infrasound observed in the Czech Republic during convective storms 9 - 10 July 2011

    NASA Astrophysics Data System (ADS)

    Sindelarova, Tereza; Skripnikova, Katerina; Chum, Jaroslav; Lastovicka, Jan; Base, Jiri; Mosna, Zbysek

    2013-04-01

    An experimental array has been built at the observatory Panska Ves, Czech Republic (50°31' N 14°34' E). It is equipped with three differential microbarographs (type ISGM03). The sensors are arranged in an equilateral triangle; the distance between sensors is approximately 200 m. Using this array, we studied infrasound phenomena related with intense convective storms on 9-10 July 2011. In the studied frequency range 0.1-4 Hz, we observed phenomena of short duration related to lightning activity and also signals that persisted tens of seconds. The latter type of infrasound signals is the object of the current study. Azimuth of arrival of the signals corresponded well with position of convective storms towards the observatory and changed as convective storms were travelling across the Czech Republic from the south west to the north east. Apparent velocity often exceeded 340 m/s (considered as the local speed of sound); it means the signals arrived under some elevation angle (up to 40°). The azimuth of arrival showed higher variability at the beginning of the event; we repeatedly observed gradual variations in azimuth up to the change of 90°. The azimuth of arrival was more stable after 02 UT on 10 July 2011.

  20. Spatial characteristics of observed precipitation fields: A catalog of summer storms in Arizona, Volume 1

    NASA Technical Reports Server (NTRS)

    Fennessey, N. M.; Eagleson, P. S.; Qinliang, W.; Rodrigues-Iturbe, I.

    1986-01-01

    Eight years of summer raingage observations are analyzed for a dense, 93 gage, network operated by the U. S. Department of Agriculture, Agricultural Research Service, in their 150 sq km Walnut Gulch catchment near Tucson, Arizona. Storms are defined by the total depths collected at each raingage during the noon to noon period for which there was depth recorded at any of the gages. For each of the resulting 428 storms, the 93 gage depths are interpolated onto a dense grid and the resulting random field is anlyzed. Presented are: storm depth isohyets at 2 mm contour intervals, first three moments of point storm depth, spatial correlation function, spatial variance function, and the spatial distribution of total rainstorm depth.

  1. Study of Ardmore, Oklahoma storm clouds. I - Convective storm cloud initiation and development based on the remote sensing gravity-wave-induced convection. II - Satellite infrared remote sensing and numerical simulation

    NASA Technical Reports Server (NTRS)

    Hung, R. J.; Tsao, Y. D.

    1991-01-01

    The role of gravity waves is discussed with respect to the vertical velocity of convection. Specific attention is given to wave-induced convection which contributes to the fractions of formation and the development of severe convective storms. Large-amplitude gravity waves and convective instability were investigated in storm clouds above Ardmore, Oklahoma. Rapid-scan satellite imagery and radar summaries provide evidence of water-vapor condensation related to convection which is introduced by gravity waves. Gravity wave periods of 35 minutes are found to initiate weak convection, which can be intensified by gravity waves with periods of 20 minutes. The convective motion reaches a maximum about one hour before funnel clouds develop. Other mechanisms which contribute to convective motion are considered, but gravity waves are the major contributor to the initiation, formation, and development of mesoscale storm clouds. Cloud modeling based on satellite imagery and sounding data showed that by overshooting cloud tops that penetrated the tropopause, storm clouds mature; that these clouds collapse about 9 minutes before the touchdown of tornadoes; and that cloud tops collapse at a high rate about 6 minutes before tornadoes lift off.

  2. Saturn's Great Storm of 2010-2011: Cloud particles containing ammonia and water ices indicate a deep convective origin. (Invited)

    NASA Astrophysics Data System (ADS)

    Sromovsky, L. A.; Baines, K. H.; Fry, P.

    2013-12-01

    Saturn's Great Storm of 2010-2011 was first detected by amateur astronomers in early December 2010 and later found in Cassini Imaging Science Subsystem (ISS) images taken on 5 December, when it took the form of a 1000 km wide bright spot. Within a week the head of the storm grew by a factor of ten in width and within a few months created a wake that encircled the planet. This is the sixth Great Saturn Storm in recorded history, all having appeared in the northern hemisphere, and most near northern summer solstice at intervals of roughly 30 years (Sanchez-Lavega et al. 1991, Nature 353, 397-401). That the most recent storm appeared 10 years early proved fortunate because Cassini was still operating in orbit around Saturn and was able to provide unique observations from which we could learn much more about these rare and enormous events. Besides the dramatic dynamical effects displayed at the visible cloud level by high-resolution imaging observations (Sayanagi et al. 2013, Icarus 223, 460-478), dramatic thermal changes also occurred in the stratosphere above the storm (Fletcher et al. 2011, Science 332, 1413), and radio measurements of lightning (Fischer et al., 2011, Nature 475, 75-77) indicated strong convective activity at deeper levels. Numerical models of Saturn's Giant storms (Hueso and Sanchez-Lavega 2004, Icarus 172, 255-271) suggest that they are fueled by water vapor condensation beginning at the 10-12 bar level, some 250 km below the visible cloud tops. That idea is also supported by our detection of water ice near the cloud tops (Sromovsky et al. 2013, Icarus 226, 402-418). From Cassini VIMS spectral imaging taken in February 2011, we learned that the storm's cloud particles are strong absorbers of sunlight at wavelengths from 2.8 to 3.1 microns. Such absorption is not seen on Saturn outside of storm regions, implying a different kind of cloud formation process as well as different cloud composition inside the storm region. We found compelling evidence

  3. Lightning, overshooting top and hail characteristics for strong convective storms in Central Europe

    NASA Astrophysics Data System (ADS)

    Jurković, Petra Mikuš; Mahović, Nataša Strelec; Počakal, Damir

    2015-07-01

    Lightning activity in storms with overshooting tops and hail-producing storms over Central Europe is studied, in order to find typical lightning characteristics that can be useful in nowcasting of the severity of the storm and its ability to produce hail. The first part of the study gives the analysis of lightning activity in thunderstorms with overshooting tops (OT) for the warm part of the year (May-September) from 2009 to 2010 over central and southeastern Europe. Deep convective clouds with OT were detected in Meteosat Second Generation (MSG) Spinning Enhanced Visible and Infrared Imager (SEVIRI) data, using methods based on the infrared window (IRW, 10.8 μm) channel and absorption channels of water vapor (WV, 6.2 μm) and ozone (O3, 9.7 μm) in the form of brightness temperature differences. The locations and times of the detected OT were compared to the distribution and types of lightning strokes, which were provided by the LINET Lightning Location System. The results show that the spatial distribution of lightning generally coincides with the spatial distribution of the detected OT. The largest numbers of lightning strokes and OT were found in western Hungary, southeastern Austria, northeastern Slovenia and the northern Adriatic. The largest number of OT occurred between 1600 and 1800 UTC, whereas from 0600 to 1000 UTC OT detections were rather rare. Lightning activity showed a similar temporal distribution, with an increase in lightning activity evident at or close to the time of the OT detections. At the time of and close to the location of the OT, the lightning was found to occur well above the tropopause and was clearly related to the OT of cumulonimbus clouds. In the second part of the study, lightning characteristics are studied for 35 events of hail-producing thunderstorms over Croatia in the summer months (May to September), from 2008 to 2012. The lightning distribution, also registered by LINET, was compared to hail parameters based on measurements

  4. The Impacts of Microphysics and Planetary Boundary Layer Physics on Model Simulations of U. S. Deep South Summer Convection

    NASA Technical Reports Server (NTRS)

    McCaul, E. W., Jr.; Case, J. L.; Zavodsky, B. T.; Srikishen, J.; Medlin, J. M.; Wood, L.

    2014-01-01

    Inspection of output from various configurations of high-resolution, explicit convection forecast models such as the Weather Research and Forecasting (WRF) model indicates significant sensitivity to the choices of model physics parameterizations employed. Some of the largest apparent sensitivities are related to the specifications of the cloud microphysics and planetary boundary layer physics packages. In addition, these sensitivities appear to be especially pronounced for the weakly-sheared, multicell modes of deep convection characteristic of the Deep South of the United States during the boreal summer. Possible ocean-land sensitivities also argue for further examination of the impacts of using unique ocean-land surface initialization datasets provided by the NASA Short-term Prediction Research and Transition (SPoRT Center to select NOAA/NWS weather forecast offices. To obtain better quantitative understanding of these sensitivities and also to determine the utility of the ocean-land initialization data, we have executed matrices of regional WRF forecasts for selected convective events near Mobile, AL (MOB), and Houston, TX (HGX). The matrices consist of identically initialized WRF 24-h forecasts using any of eight microphysics choices and any of three planetary boundary layer choices. The resulting 24 simulations performed for each event within either the MOB or HGX regions are then compared to identify the sensitivities of various convective storm metrics to the physics choices. Particular emphasis is placed on sensitivities of precipitation timing, intensity, and coverage, as well as amount and coverage of lightning activity diagnosed from storm kinematics and graupel in the mixed phase layer. The results confirm impressions gleaned from study of the behavior of variously configured WRF runs contained in the ensembles produced each spring at the Center for the Analysis and Prediction of Storms, but with the benefit of more straightforward control of the

  5. The Impact of Microphysics and Planetary Boundary Layer Physics on Model Simulation of U.S. Deep South Summer Convection

    NASA Technical Reports Server (NTRS)

    McCaul, Eugene W., Jr.; Case, Jonathan L.; Zavodsky, Bradley T.; Srikishen, Jayanthi; Medlin, Jeffrey M.; Wood, Lance

    2014-01-01

    Inspection of output from various configurations of high-resolution, explicit convection forecast models such as the Weather Research and Forecasting (WRF) model indicates significant sensitivity to the choices of model physics pararneterizations employed. Some of the largest apparent sensitivities are related to the specifications of the cloud microphysics and planetary boundary layer physics packages. In addition, these sensitivities appear to be especially pronounced for the weakly-sheared, multicell modes of deep convection characteristic of the Deep South of the United States during the boreal summer. Possible ocean-land sensitivities also argue for further examination of the impacts of using unique ocean-land surface initialization datasets provided by the NASA Short-term Prediction Research and Transition (SPoRn Center to select NOAAlNWS weather forecast offices. To obtain better quantitative understanding of these sensitivities and also to determine the utility of the ocean-land initialization data, we have executed matrices of regional WRF forecasts for selected convective events near Mobile, AL (MOB), and Houston, TX (HGX). The matrices consist of identically initialized WRF 24-h forecasts using any of eight microphysics choices and any of three planetary boWldary layer choices. The resulting 24 simulations performed for each event within either the MOB or HGX regions are then compared to identify the sensitivities of various convective storm metrics to the physics choices. Particular emphasis is placed on sensitivities of precipitation timing, intensity, and coverage, as well as amount and coverage oflightuing activity diagnosed from storm kinematics and graupel in the mixed phase layer. The results confirm impressions gleaned from study of the behavior of variously configured WRF runs contained in the ensembles produced each spring at the Center for the Analysis and Prediction of Storms, but with the benefit of more straightforward control of the

  6. North Atlantic summer storm tracks over Europe dominated by internal variability over the past millennium

    NASA Astrophysics Data System (ADS)

    Gagen, Mary H.; Zorita, Eduardo; McCarroll, Danny; Zahn, Matthias; Young, Giles H. F.; Robertson, Iain

    2016-08-01

    Certain large, sustained anomalies in European temperatures in the past millennium are probably the result of internal variation. Such internal variations can modulate regional temperatures away from the expected response to greenhouse gas forcing. Here we assess the causes of European summer temperature variability over the past millennium using temperature observations, simulations and reconstructions. We find multidecadal-mean summer temperatures have varied within a span of 1 K, largely controlled by external forcing. By contrast, we find subcontinental variations, described by the temperature contrast between northern and southern Europe (the meridional temperature gradient), vary with a span of 2 K, and are controlled by internal processes. These variations are the result of redistributions of precipitation and cloud cover linked to oscillations in the position of the summer storm track. In contrast to recent twentieth-century winter-time trends, variations of the summer storm track over the past millennium show a weak response to external forcing, and instead are dominated by stochastic internal variability. We argue that the response of European summer temperatures to anthropogenic greenhouse forcing is likely to be spatially modulated by the same stochastic internal processes that have caused periods of cool, wet summers in northern Europe over the last millennium.

  7. CONVECTIVE BURSTS AND THE COUPLING OF SATURN'S EQUATORIAL STORMS AND INTERIOR ROTATION

    SciTech Connect

    Heimpel, Moritz; Aurnou, Jonathan M. E-mail: aurnou@ucla.edu

    2012-02-10

    Temporal variations of Saturn's equatorial jet and magnetic field hint at rich dynamics coupling the atmosphere and the deep interior. However, it has been assumed that rotation of the interior dynamo must be steady over tens of years of modern observations. Here we use a numerical convection model and scaling estimates to show how equatorial convective bursts can transfer angular momentum to the deeper interior. The numerical model allows angular momentum transfer between a fluid outer spherical shell and a rigid inner sphere. Convection drives a prograde equatorial jet exhibiting quasiperiodic bursts that fill the equatorial volume outside the tangent cylinder. For each burst strong changes in the equatorial surface velocity are associated with retrograde torque on the inner sphere. Our results suggest that Saturn's Great White Spot, a giant storm that was observed to fill the equatorial region in 1990, could mobilize a volume of fluid carrying roughly 15% of Saturn's moment of inertia. Conservation of angular momentum then implies that a 20% change in the equatorial jet angular velocity could change the average interior rotation rate by about 0.1%-roughly an order of magnitude less than the apparent rotation rate changes associated with Saturn's kilometric radio (SKR) signal. However, if the SKR signal originates outside the liquid metal core in a 'planetary tachocline' that separates the layer of fast zonal flow from the magnetically controlled and slowly convecting deep interior, then convective bursts can provide a possible mechanism for the observed {approx}1% SKR changes.

  8. Ionospheric convection during the magnetic storm of 20-21 March 1991

    NASA Technical Reports Server (NTRS)

    Taylor, J. R.; Yeoman, T. K.; Lester, M.; Buonsanto, M. J.; Scali, J. L.; Ruohoniemi, J. M.; Kelly, J. D.

    1994-01-01

    We report on the response of high-latitude ionospheric convection during the magnetic storm of March 20-21 1990. IMP-8 measurements of solar wind plasma and interplanetary magnetic field (IMF), ionospheric convection flow measurements from the Wick and Goose Bay coherent radars, EISCAT, Millstone Hill and Sondrestorm incoherent radars and three digisondes at Millstone Hill, Goose Bay and Qaanaaq are presented. Two intervals of particular interest have been indentified. The first starts with a storm sudden commencement at 2243 UT on March 20 and includes the ionospheric activity in the following 7 h. The response time of the ionospheric convection to the southward tuning of the IMF in the dusk to midnight local times is found to be approximately half that measured in a similar study at comparable local times during more normal solar wind conditions. A subsequent reconfiguration of the nightside convection pattern was also observed, although it was not possible to distinguish between effects due to possible changes in B(sub y) and effects due to substorm activity. The second interval, 1200-2100 UT 21 March 1990, included a southward turning of the IMF which resulted in the B(sub z) component becoming -10 nT. The response time on the dayside to this change in the IMF at the magnetopause was approximately 15 min to 30 min which is a factor of approximately 2 greater than those previously measured at higher latitudes. A movement of the nightside flow reversal, possibly driven by current systems associated with the substorm expansion phases, was observed, implying that the nightside convection pattern can be dominated by substorm activity.

  9. Hybrid ensemble-3DVar radar data assimilation for the short-term prediction of convective storms

    NASA Astrophysics Data System (ADS)

    Carley, Jacob R.

    This two-part study develops and tests a hybrid ensemble-3DVar radar data assimilation system for the short-term prediction of convective storms. A key component of this work is the use of the operational regional numerical weather prediction infrastructure of the United States National Weather Service (NWS). Recently, the NWS's Gridpoint Statistical Interpolation system (GSI) has been extended to include a hybrid ensemble-3DVar assimilation capability, allowing for the inclusion of flow dependent background error statistics in the 3DVar cost function. A convenient aspect of the hybrid ensemble-3DVar approach is its resource manageability. The initial implementation of the system may only use 3DVar and the hybrid aspect can be implemented gradually where additional ensemble members can be added as computational resources allow. Therefore the hybrid ensemble-3DVar method may be a particularly appealing approach for an operational numerical weather prediction (NWP) center where resources are at a premium. The first part of this study focuses on the development of a storm-scale, hybrid ensemble-3DVar radar data assimilation system. An observation operator for radar reflectivity is introduced, static background errors for additional hydrometeor control variables are obtained, an ensemble prediction system is implemented, and an algorithm is developed to assimilate radar observations. This system is applied to a real-data case which exhibits varying convective modes. It is found that, when compared to 3DVar, the hybrid ensemble-3DVar assimilation approach provides a closer fit to observations, produces cold pools which are much stronger than what was observed in the 3DVar experiment, and all experiments have a vertical velocity field at the final analysis time which exhibits generally weak upward vertical motion fields. The weak vertical motion field is hypothesized to be a result of the lack of vertical velocity control variable and thus there is no coupling amongst

  10. Ionospsheric observation of enhanced convection-initiated gravity waves during tornadic storms

    NASA Technical Reports Server (NTRS)

    Hung, R. J.

    1981-01-01

    Atmospheric gravity waves associated with tornadoes, with locally severe storms occuring with tornadoes, and with hurricanes were studied through the coupling between the ionosphere and the troposphere. Reverse group ray tracing computations of gravity waves observed by an ionospheric Doppler sounder array were analyzed. The results of ray tracing computations and comparisons between the computed location of the wave sources and with conventional meteorological data indicate that the computed sources of the waves were near the touchdown of the tornadoes, near the eye of the hurricanes, and directly on the squall line of the severe thunderstorms. The signals excited occurred one hour in advance of the tornadoes and three hours in advance of the hurricanes. Satellite photographs show convective overshooting turrets occurring at the same locations and times the gravity waves were being excited. It is suggested that gravity wave observations, conventional meteorological data, and satellite photographs be combined to develop a remote sensing technique for detecting severe storms.

  11. Influence of the Convection Electric Field Models on Predicted Plasmapause Positions During Magnetic Storms

    NASA Technical Reports Server (NTRS)

    Pierrard, V.; Khazanov, G.; Cabrera, J.; Lemaire, J.

    2007-01-01

    In the present work, we determine how three well documented models of the magnetospheric electric field, and two different mechanisms proposed for the formation of the plasmapause influence the radial distance, the shape and the evolution of the plasmapause during the geomagnetic storms of 28 October 2001 and of 17 April 2002. The convection electric field models considered are: Mcllwain's E51) electric field model, Volland-Stern's model and Weimer's statistical model compiled from low-Earth orbit satellite data. The mechanisms for the formation of the plasmapause to be tested are: (i) the MHD theory where the plasmapause should correspond to the last-closed- equipotential (LCE) or last-closed-streamline (LCS), if the E-field distribution is stationary or time-dependent respectively; (ii) the interchange mechanism where the plasmapause corresponds to streamlines tangent to a Zero-Parallel-Force surface where the field-aligned plasma distribution becomes convectively unstable during enhancements of the E-field intensity in the nightside local time sector. The results of the different time dependent simulations are compared with concomitant EUV observations when available. The plasmatails or plumes observed after both selected geomagnetic storms are predicted in all simulations and for all E-field models. However, their shapes are quite different depending on the E-field models and the mechanisms that are used. Despite the partial success of the simulations to reproduce plumes during magnetic storms and substorms, there remains a long way to go before the detailed structures observed in the EUV observations during periods of geomagnetic activity can be accounted for very precisely by the existing E-field models. Furthermore, it cannot be excluded that the mechanisms currently identified to explain the formation of "Carpenter's knee" during substorm events, will', have to be revised or complemented in the cases of geomagnetic storms.

  12. Gravity shear waves atop the cirrus layer of intense convective storms

    NASA Technical Reports Server (NTRS)

    Stobie, J. G.

    1975-01-01

    Recent visual satellite photographs of certain intense convective storms have revealed concentric wave patterns. A model for the generation and growth of these waves is proposed. The proposed initial generating mechanism is similar to the effect noticed when a pebble is dropped into a calm pond. The penetration of the tropopause by overshooting convection is analogous to the pebble's penetration of the water's surface. The model for wave growth involves instability due to the wind shear resulting from the cirrus outflow. This model is based on an equation for the waves' phase speed which is similar to the Helmholtz equation. It, however, does not assume an incompressible atmosphere, but rather assumes density is a logarithmic function of height. Finally, the model is evaluated on the two mid-latitude and three tropical cases. The data indicate that shearing instability may be a significant factor in the appearance of these waves.

  13. Midweek Increase in U.S. Summer Rain and Storm Heights, Suggests Air Pollution Invigorates Rainstorms

    NASA Technical Reports Server (NTRS)

    Bell, Thomas L.; Rosenfeld, Daniel; Kim, Kyu-Myong; Yoo, Jung-Moon; Hahnenberger, Maura

    2007-01-01

    Tropical Rainfall Measuring Mission (TRMM) satellite data show a significant midweek increase in summertime rainfall over the southeast U.S., due to afternoon intensification. TRMM radar data show a significant midweek increase in rain area and in the heights reached by afternoon storms. Weekly variations in model-reanalysis wind patterns over the region and in rain-gauge data are consistent with the satellite data. A midweek decrease of rainfall over the nearby Atlantic is also seen. EPA measurements of particulate concentrations show a midweek peak over much of the U.S. These observations are consistent with the theory that anthropogenic air pollution suppresses cloud-drop coalescence and early rainout during the growth of thunderstorms over land, allowing more water to be carried above the 0 C isotherm, where freezing yields additional latent heat, invigorating the storms--most dramatically evidenced by the shift in the midweek distribution of afternoon-storm heights--and producing large ice hydrometeors. The enhanced convection induces regional convergence, uplifting and an overall increase of rainfall. Compensating downward air motion suppresses convection over the adjacent ocean areas. Pre-TRMM-era data suggest that the weekly cycle only became strong enough to be detectable beginning in the 1980's. Rain-gauge data also suggest that a weekly cycle may have been detectable in the 1940's, but with peak rainfall on Sunday or Monday, possibly explained by the difference in composition of aerosol pollution at that time. This "weekend effect" may thus offer climate researchers an opportunity to study the regional climate-scale impact of aerosols on storm development and monsoon-like circulation.

  14. Intense Convective Storms with Little or No Lightning over Central Arizona: A Case of Inadvertent Weather Modification?.

    NASA Astrophysics Data System (ADS)

    Maddox, Robert A.; Howard, Kenneth W.; Dempsey, Charles L.

    1997-04-01

    On 20/21 August 1993, deep convective storms occurred across much of Arizona, except for the southwestern quarter of the state. Several storms were quite severe, producing downbursts and extensive wind damage in the greater Phoenix area during the late afternoon and evening. The most severe convective storms occurred from 0000 to 0230 UTC 21 August and were noteworthy in that, except for the first reported severe thunderstorm, there was almost no cloud-to-ground (CG) lightning observed during their life cycles. Other intense storms on this day, particularly early storms to the south of Phoenix and those occurring over mountainous terrain to the north and east of Phoenix, were prolific producers of CG lightning. Radar data for an 8-h period (2000 UTC 20 August-0400 UTC 21 August) indicated that 88 convective cells having maximum reflectivities greater than 55 dBZ and persisting longer than 25 min occurred within a 200-km range of Phoenix. Of these cells, 30 were identified as `low-lightning' storms, that is, cells having three or fewer detected CG strikes during their entire radar-detected life cycle. The region within which the low-lightning storms were occurring spread to the north and east during the analysis period.Examination of the reflectivity structure of the storms using operational Doppler radar data from Phoenix, and of the supportive environment using upper-air sounding data taken at Luke Air Force Base just northwest of Phoenix, revealed no apparent physical reasons for the distinct difference in observed cloud-to-ground lightning character between the storms in and to the west of the immediate Phoenix area versus those to the north, east, and south. However, the radar data do reveal that several extensive clouds of chaff initiated over flight-restricted military ranges to the southwest of Phoenix. The prevailing flow advected the chaff clouds to the north and east. Convective storms that occurred in the area likely affected by the dispersing chaff

  15. Classification and Analysis of Four Types of Elevated Nocturnal Convective Initiation During Summer 2015

    NASA Astrophysics Data System (ADS)

    Stelten, S. A.; Gallus, W. A., Jr.

    2015-12-01

    A large portion of precipitation seen in the Great Plains region of the United States falls from nocturnal convection. Quite often, nocturnally initiated convection may grow upscale into a Mesoscale Convective System (MCS) that in turn may cause high impact weather events such as severe wind, flooding, and even tornadoes. Thus, correctly predicting nocturnal convective initiation is an integral part of forecasting for the Great Plains. Unfortunately, it is also one of the most challenging aspects of forecasting for this region. Many forecasters familiar with the Great Plains region have noted that elevated nocturnal convective initiation seems to favor a few distinct and rather diverse modes, which pose varying degrees of forecasting difficulties. This study investigates four of these modes, including initiation caused by the interaction of the low level jet and a frontal feature, initiation at the nose of the low level jet without the presence of a frontal feature, linear features ahead of and perpendicular to a forward propagating MCS, and initiation occurring with no discernible large scale forcing mechanism. Improving elevated nocturnal convective initiation forecasts was one of the primary goals of the Plains Elevated Convection At Night (PECAN) field campaign that took place from June 1 to July 15, 2015, which collected a wealth of convective initiation data. To coincide with these data sets, nocturnal convective initiation episodes from the 2015 summer season were classified into each of the aforementioned groups. This allowed for a thorough investigation of the frequency of each type of initiation event, as well as identification of typical characteristics of the atmosphere (forcing mechanisms present, available instability, strength/location of low level jet, etc.) during each event type. Then, using archived model data and the vast data sets collected during the PECAN field campaign, model performance during PECAN for each convective initiation mode was

  16. Enhanced summer convective rainfall at Alpine high elevations in response to climate warming

    NASA Astrophysics Data System (ADS)

    Giorgi, Filippo; Torma, Csaba; Coppola, Erika; Ban, Nikolina; Schär, Christoph; Somot, Samuel

    2016-08-01

    Global climate projections consistently indicate a future decrease in summer precipitation over the European Alps. However, topography can substantially modulate precipitation change signals. For example, the shadowing effect by topographic barriers can modify winter precipitation change patterns, and orographic convection might also play an important role. Here we analyse summer precipitation over the Alpine region in an ensemble of twenty-first-century projections with high-resolution (~12 km) regional climate models driven by recent global climate model simulations. A broad-scale summer precipitation reduction is projected by both model ensembles. However, the regional models simulate an increase in precipitation over the high Alpine elevations that is not present in the global simulations. This is associated with increased convective rainfall due to enhanced potential instability by high-elevation surface heating and moistening. The robustness of this signal, which is found also for precipitation extremes, is supported by the consistency across models and future time slices, the identification of an underlying mechanism (enhanced convection), results from a convection-resolving simulation, the statistical significance of the signal and the consistency with some observed trends. Our results challenge the picture of a ubiquitous decrease of summer precipitation over the Alps found in coarse-scale projections.

  17. Sprite-producing Convective Storms within the Colorado Lightning Mapping Array

    NASA Astrophysics Data System (ADS)

    Lyons, W. A.; Cummer, S. A.; Rison, W.; Krehbiel, P. R.; Lang, T. J.; Rutledge, S. A.; Lu, G.; Stanley, M. A.; Ashcraft, T.; Nelson, T. E.

    2012-12-01

    The multi-year, multi-institution effort entitled Physical Origins of Coupling to the Upper Atmosphere from Lightning (PhOCAL), has among its goals to qualitatively understand the meteorology and lightning flash characteristics that produce the unusual and/or very energetic lightning responsible for phenomena such as sprites, halos, elves, blue jets and gigantic jets, collectively known as Transient Luminous Events (TLEs). A key task is to obtain simultaneous video, ideally with a high-speed imager (HSI), of both a TLE and its parent lightning discharge, within the domain of a 3-D Lightning Mapping Array (LMA). While conceptually simple, this task is logistically quite complicated. In 2012, a new 15-station Colorado LMA (COLMA) became operational, covering northeastern Colorado, with the Yucca Ridge Field Station (YRFS) near its western edge. The National Charge Moment Change Network (CMCN), which since 2007 has been documenting sprite-class +CGs (those with impulse change moment changes >100 C km), indicates that a strong gradient of energetic +CGs exists west-to-east through the COLMA, with the most likely region for sprite-producing storms being in the COLMA eastern fringes (western Kansas and Nebraska). Yet, on 8 and 25 June, 2012, intense convective systems formed in the COLMA along and just east of the Front Range, producing severe weather and intense lightning. On the 8th, four sprite parent +CGs were captured at 3000 fps from YRFS with the sprites confirmed by dual (conventional speed) cameras in New Mexico. In a second storm on the 25th, viewing conditions prevented +CG video acquisition, but sprites were logged over the COLMA and detailed reconstructions of the discharges are being made. The parent discharges often began as upward negative leaders propagating into a mid-level positive charge layer at 8-10 km. They often originated within or near the convective core before expanding outward into a stratiform region and involving several hundred square

  18. Evaluation and development of satellite inferences of convective storm intensity using combined case study and thunderstorm model simulations

    NASA Technical Reports Server (NTRS)

    Cotton, W. R.; Tripoli, G. J.

    1982-01-01

    Observational requirements for predicting convective storm development and intensity as suggested by recent numerical experiments are examined. Recent 3D numerical experiments are interpreted with regard to the relationship between overshooting tops and surface wind gusts. The development of software for emulating satellite inferred cloud properties using 3D cloud model predicted data and the simulation of Heymsfield (1981) Northern Illinois storm are described as well as the development of a conceptual/semi-quantitative model of eastward propagating, mesoscale convective complexes forming to the lee of the Rocky Mountains.

  19. Assessment of the European Severe Convective Storm Climatology using Reanalysis Data

    NASA Astrophysics Data System (ADS)

    Pistotnik, Georg; Groenemeijer, Pieter; Kühne, Thilo

    2013-04-01

    Thunderstorms and their accompanying phenomena like large hail, severe wind gusts, tornadoes and excessive precipitation are increasingly recognized as an important hazard to life and property in Europe. Within the project STEPCLIM ("Severe Thunderstorm Evaluation and Predictability in Climate Models"), we link historic severe thunderstorm events in Europe to atmospheric conditions resolved by reanalysis data. The aim is to find a relation between quantities, which can be represented by relatively coarse climate models, and the occurrence of short-lived and local severe weather phenomena associated with convection. At a later stage, this relation will be applied to climate forecast data, so that the effects of climate change on the frequency and intensity of severe convective storms can be investigated. A set of parameters is defined for the characterization of the local state of the atmosphere at any given point in place and time. These parameters represent the "ingredients" for severe thunderstorms, namely instability, vertical wind shear, and a measure of support for convective initiation. They are calculated from 6-hourly ERA-Interim reanalysis fields (1979-2011). The such derived fields are compared with the occurrence or non-occurrence of severe weather phenomena according to the quality-controlled severe storm reports collected in the European Severe Weather Database (ESWD). A logistic regression is then fitted in order to find the best relation between a given combination of parameters and the associated severe weather probability. This relation is postulated to be invariant against any changes in climate, an assumption that is justified by the physics-based nature of the chosen parameters. With this restriction, the derived relation can be used to estimate future severe weather frequencies based on modeled climatic changes of the underlying parameter distributions. In this presentation, emphasis is put on the used methodology and on a way to deal with

  20. Weakening of the mid-latitude summer nighttime anomaly during geomagnetic storms

    NASA Astrophysics Data System (ADS)

    Liu, Huixin; Yamamoto, Mamoru

    2011-04-01

    This brief report presents geomagnetic storm effects on the formation and characteristics of the midlatitude summer nighttime anomaly (MSNA). This anomaly is a phenomenon where the diurnal variation of the plasma density maximizes at night instead of day. Under disturbed geomagnetic conditions, the MSNA is found to have smaller spatial coverage, lower magnitude of the reversed diurnal cycle, and shorter duration of the nighttime enhancement. All these features demonstrate a weakening of the MSNA. In addition, the nighttime maximum tends to occur at earlier local time. These effects can be reasonably understood in the frame of storm-induced equatorward wind and the molecular-rich air it carries along with. For instance, the shrink of the spatial coverage is essentially a dominant effect of the molecular-rich air, which tends to deplete the plasma significantly on the poleward edge of the MSNA region. On the other hand, the smaller magnitude and the shorter duration seem to be mainly caused by the storm-induced equatorward wind. Storm effects presented here add further evidence to the pivot role of effective neutral wind in the formation of MSNA.

  1. Recent Trends of Summer Convective and Stratiform Precipitation in Mid-Eastern China.

    PubMed

    Fu, Yunfei; Chen, Fengjiao; Liu, Guosheng; Yang, Yuanjian; Yuan, Renmin; Li, Rui; Liu, Qi; Wang, Yu; Zhong, Lei; Sun, Liang

    2016-01-01

    Many studies have reported on the trends of precipitation in Mid-Eastern China (EC). However, the trends of convective and stratiform precipitation are still unknown. Here, we examine the trends of summer convective and stratiform precipitation in EC from 2002 to 2012 on the basis of the TRMM observations. Results revealed that the rain frequency (RF) for both convective and stratiform precipitation increased in majority regions of Southern EC (SEC), but decreased in Northwest part of Northern EC (NEC). The decreasing rate of RF for stratiform precipitation in NEC is twice as much as that for convective precipitation, while the increase of convective precipitation in SEC is more evident than stratiform precipitation. The rain rate (RR) exhibited a decreasing trend in most portions of EC for both convective and stratiform precipitation. In SEC, neither PW nor WVT has good ability in explaining the precipitation variability. However, in NEC, PW is closely correlated to convective RF and WVT is more closely related to stratiform RF. PMID:27604846

  2. Recent Trends of Summer Convective and Stratiform Precipitation in Mid-Eastern China

    PubMed Central

    Fu, Yunfei; Chen, Fengjiao; Liu, Guosheng; Yang, Yuanjian; Yuan, Renmin; Li, Rui; Liu, Qi; Wang, Yu; Zhong, Lei; Sun, Liang

    2016-01-01

    Many studies have reported on the trends of precipitation in Mid-Eastern China (EC). However, the trends of convective and stratiform precipitation are still unknown. Here, we examine the trends of summer convective and stratiform precipitation in EC from 2002 to 2012 on the basis of the TRMM observations. Results revealed that the rain frequency (RF) for both convective and stratiform precipitation increased in majority regions of Southern EC (SEC), but decreased in Northwest part of Northern EC (NEC). The decreasing rate of RF for stratiform precipitation in NEC is twice as much as that for convective precipitation, while the increase of convective precipitation in SEC is more evident than stratiform precipitation. The rain rate (RR) exhibited a decreasing trend in most portions of EC for both convective and stratiform precipitation. In SEC, neither PW nor WVT has good ability in explaining the precipitation variability. However, in NEC, PW is closely correlated to convective RF and WVT is more closely related to stratiform RF. PMID:27604846

  3. Recent Trends of Summer Convective and Stratiform Precipitation in Mid-Eastern China

    NASA Astrophysics Data System (ADS)

    Fu, Yunfei; Chen, Fengjiao; Liu, Guosheng; Yang, Yuanjian; Yuan, Renmin; Li, Rui; Liu, Qi; Wang, Yu; Zhong, Lei; Sun, Liang

    2016-09-01

    Many studies have reported on the trends of precipitation in Mid-Eastern China (EC). However, the trends of convective and stratiform precipitation are still unknown. Here, we examine the trends of summer convective and stratiform precipitation in EC from 2002 to 2012 on the basis of the TRMM observations. Results revealed that the rain frequency (RF) for both convective and stratiform precipitation increased in majority regions of Southern EC (SEC), but decreased in Northwest part of Northern EC (NEC). The decreasing rate of RF for stratiform precipitation in NEC is twice as much as that for convective precipitation, while the increase of convective precipitation in SEC is more evident than stratiform precipitation. The rain rate (RR) exhibited a decreasing trend in most portions of EC for both convective and stratiform precipitation. In SEC, neither PW nor WVT has good ability in explaining the precipitation variability. However, in NEC, PW is closely correlated to convective RF and WVT is more closely related to stratiform RF.

  4. Recent Trends of Summer Convective and Stratiform Precipitation in Mid-Eastern China.

    PubMed

    Fu, Yunfei; Chen, Fengjiao; Liu, Guosheng; Yang, Yuanjian; Yuan, Renmin; Li, Rui; Liu, Qi; Wang, Yu; Zhong, Lei; Sun, Liang

    2016-09-08

    Many studies have reported on the trends of precipitation in Mid-Eastern China (EC). However, the trends of convective and stratiform precipitation are still unknown. Here, we examine the trends of summer convective and stratiform precipitation in EC from 2002 to 2012 on the basis of the TRMM observations. Results revealed that the rain frequency (RF) for both convective and stratiform precipitation increased in majority regions of Southern EC (SEC), but decreased in Northwest part of Northern EC (NEC). The decreasing rate of RF for stratiform precipitation in NEC is twice as much as that for convective precipitation, while the increase of convective precipitation in SEC is more evident than stratiform precipitation. The rain rate (RR) exhibited a decreasing trend in most portions of EC for both convective and stratiform precipitation. In SEC, neither PW nor WVT has good ability in explaining the precipitation variability. However, in NEC, PW is closely correlated to convective RF and WVT is more closely related to stratiform RF.

  5. Aerosol Indirect Effects on the Cold Pool Characteristics of Convective Storms and Their Subsequent Feedbacks to Convective Development and Surface Precipitation

    NASA Astrophysics Data System (ADS)

    van den Heever, S. C.

    2008-12-01

    Enhanced aerosol concentrations are often associated with a decrease in the surface precipitation through their suppression of the warm rain process. Such changes to the surface precipitation may, however, have an impact on the associated cold pool characteristics, thereby affecting subsequent convective development and the resultant surface precipitation. This dynamic response of the cold pool to enhanced aerosol concentrations may therefore at times offset the aerosol indirect effects on precipitation through its organization of the convection. The relationship between aerosol indirect effects on precipitation characteristics and the associated dynamic forcing of the cold pool has been investigated through the use of several cloud-resolving simulations of convective storms over Florida. Toward the end of NASA's CRYSTAL-FACE field campaign conducted over Florida during July 2002, high concentrations of Saharan dust, which can serve as cloud condensation nuclei and ice nuclei, were observed over the peninsula of Florida. Cloud-resolving model simulations have been conducted using the Regional Atmospheric Modeling System (RAMS) to investigate the impacts of varying aerosol concentrations on the characteristics of the convection developing over the Peninsula. The model was initialized with vertical profiles of both clean and high aerosol concentrations observed during the field campaign. Results from the simulations show that while enhanced aerosol concentrations do tend to result in a decrease in the surface precipitation throughout much of the lifecycle of the storms, there are however times when the precipitation produced by the high aerosol case is greater than that of the clean case. It is during these times that the gust fronts of the storms in the clean case have outrun their associated updrafts, resulting in a weakening of the storm system and a concomitant decrease in surface precipitation. In the high aerosol case the updrafts remain co-located with their

  6. Generation of a severe convective ionospheric storm under stable Rayleigh-Taylor conditions: triggering by meteors?

    NASA Astrophysics Data System (ADS)

    Kelley, M. C.; Ilma, R. R.

    2016-02-01

    Here we report on four events detected using the Jicamarca Radio Observatory (JRO) over an 18-year period, in which huge convective ionospheric storms (CISs) occur in a stable ionosphere. We argue that these rare events could be initiated by meteor-induced electric fields. The meteor-induced electric fields map to the bottomside of the F region, causing radar echoes and a localized CIS. If and when a localized disturbance reaches 500 km, we argue that it becomes two-dimensionally turbulent and cascades structure to both large and small scales. This leads to long-lasting structure and, almost certainly, to scintillations over a huge range of latitudes some ±15° wide and to 3 m irregularities, which backscatter the VHF radar waves. These structures located at high altitudes are supported by vortices shed by the upwelling bubble in a vortex street.

  7. The impact of vegetation on the atmospheric boundary layer and convective storms

    SciTech Connect

    Lee, T.J.

    1992-01-01

    The impact of vegetation on atmospheric boundary layer and convective storms is examined through the construction and testing of a soil-vegetation-atmospheric transfer (SVAT) model. The Land Ecosystem-Atmospheric (LEAF) model is developed using an elevated canopy structure, an above-canopy aerodynamic resistance, two in-canopy aerodynamic resistances, and one stomatal conductance functions. The air temperature and humidity are assumed to be constant in the canopy whereas the wind and radiation follow a specified vertical profile. A simple dump-bucket method is used to parameterize the interception of precipitation and a multi-layer soil model is utilized to handle the vertical transfer of soil water. Evaporation from soil and wet leaves and transpiration from dry leaves are evaluated separately. The solid water uptake is based on soil water potential rather than on length of roots. Separate energy budgets for vegetation and for soil are used in order to remove unnecessary assumptions on energy partition between the vegetation and the substrate. Primary parameters are LAI, maximum stomatal conductance, and albedo. Secondary parameters include displacement height and environmental controls on stomatal resistance function. The Multi-response Randomized Bock Permutation (MRBP) procedure is used to help choose the model parameter values. The Fourier Amplitude Sensitivity Test (FAST) is applied to understand the model behavior in response to changes in model parameters. LEAF is used to study growth of boundary layer and local thermal circulations generated by surface inhomogeneities. Results show that atmospheric boundary layer is cooler and more moist over unstressed vegetation than over bare dry soil. Thermally forced circulation can result from the juxtaposition of two vegetation types due to different biophysical characteristics. Simulations show that the surface spatial heterogeneities made by vegetation play an important role in generating local convective storms.

  8. The DYMECS Project: A Statistical Approach for the Evaluation of Convective Storms in High-Resolution NWP Models

    NASA Astrophysics Data System (ADS)

    Stein, Thorwald; Hogan, Robin; Hanley, Kirsty; Clark, Peter; Halliwell, Carol; Lean, Humphrey; Nicol, John; Plant, Robert

    2016-04-01

    National weather services increasingly use convection-permitting simulations to assist in their operational forecasts. The skill in forecasting rainfall from convection is much improved in such simulations compared to global models that rely on parameterisation schemes, but it is less obvious if and how increased model resolution or more advanced mixing and microphysics schemes improve the physical representation of convective storms. Here, we present a novel statistical approach using high-resolution radar data to evaluate the morphology, dynamics, and evolution of convective storms over southern England. In the DYMECS project (Dynamical and Microphysical Evolution of Convective Storms) we have used an innovative track-and-scan approach to target individual storms with the Chilbolton radar, which measures cloud and precipitation at scales less than 300m out to 100km. These radar observations provide three-dimensional storm volumes and estimates of updraft core strength and sizes at adequate scales to test high-resolution models. For two days of interest, we have run the Met Office forecast model at its operational configuration (1.5km grid length) and at grid lengths of 500m, 200m, and 100m. Radar reflectivity and Doppler winds were simulated from the model cloud and wind output for a like-with-like comparison against the radar observations. Our results show that although the 1.5km simulation produces similar domain-averaged rainfall as the other simulations, the majority of rainfall is produced from storms that are a factor 1.5-2 larger than observed as well as longer lived, while the updrafts of these storms are an order of magnitude greater than estimated from observations. We generally find improvements as model resolution increases, although our results depend strongly on the mixing-length parameter in the model turbulence scheme. Our findings highlight the promising role of high-resolution radar data and observational strategies targeting individual storms

  9. Dynamics of the AMPERE Region 1 Birkeland current oval during storms, substorms and steady magnetospheric convection

    NASA Astrophysics Data System (ADS)

    Baker, J. B.; Clausen, L.; Ruohoniemi, J. M.; Milan, S. E.; Kissinger, J.; Anderson, B. J.; Wing, S.

    2012-12-01

    Using radial current densities provided by the Active Magnetosphere and Planetary Electrodynamics Response Experiment (AMPERE) we employ a fitting scheme to identify the location of the maximum Region 1 field-aligned (Birkeland) current at all magnetic local times. We call this parameter the "R1 oval" and we investigate its behavior during various modes of magnetospheric activity such as storms, substorms and steady magnetospheric convection (SMCs). Results show the following: (1) during substorms the radius of the R1 oval undergoes a cyclic inflation and contraction which matches the standard paradigm for substorm growth (loading) and expansion (unloading); (2) during SMCs the R1 oval is relatively steady consistent with balanced dayside and nightside reconnection during these events; and (3) during magnetic storms the size of the R1 oval is strongly correlated with the strength of the ring current specified by the Sym-H index. We also examine the behavior of the R1 oval in the northern and southern hemispheres simultaneously as a function of season in an effort to understand the role that internal magnetosphere-ionosphere coupling influences may play in modulating the response of the magnetosphere during these various types of events.

  10. UV dosage levels in summer: increased risk of ozone loss from convectively injected water vapor.

    PubMed

    Anderson, James G; Wilmouth, David M; Smith, Jessica B; Sayres, David S

    2012-08-17

    The observed presence of water vapor convectively injected deep into the stratosphere over the United States can fundamentally change the catalytic chlorine/bromine free-radical chemistry of the lower stratosphere by shifting total available inorganic chlorine into the catalytically active free-radical form, ClO. This chemical shift markedly affects total ozone loss rates and makes the catalytic system extraordinarily sensitive to convective injection into the mid-latitude lower stratosphere in summer. Were the intensity and frequency of convective injection to increase as a result of climate forcing by the continued addition of CO(2) and CH(4) to the atmosphere, increased risk of ozone loss and associated increases in ultraviolet dosage would follow.

  11. Enhancement of seasonal prediction of East Asian summer rainfall related to western tropical Pacific convection

    NASA Astrophysics Data System (ADS)

    Lee, Doo Young; Ahn, Joong-Bae; Yoo, Jin-Ho

    2015-08-01

    The prediction skills of climate model simulations in the western tropical Pacific (WTP) and East Asian region are assessed using the retrospective forecasts of seven state-of-the-art coupled models and their multi-model ensemble (MME) for boreal summers (June-August) during the period 1983-2005, along with corresponding observed and reanalyzed data. The prediction of summer rainfall anomalies in East Asia is difficult, while the WTP has a strong correlation between model prediction and observation. We focus on developing a new approach to further enhance the seasonal prediction skill for summer rainfall in East Asia and investigate the influence of convective activity in the WTP on East Asian summer rainfall. By analyzing the characteristics of the WTP convection, two distinct patterns associated with El Niño-Southern Oscillation developing and decaying modes are identified. Based on the multiple linear regression method, the East Asia Rainfall Index (EARI) is developed by using the interannual variability of the normalized Maritime continent-WTP Indices (MPIs), as potentially useful predictors for rainfall prediction over East Asia, obtained from the above two main patterns. For East Asian summer rainfall, the EARI has superior performance to the East Asia summer monsoon index or each MPI. Therefore, the regressed rainfall from EARI also shows a strong relationship with the observed East Asian summer rainfall pattern. In addition, we evaluate the prediction skill of the East Asia reconstructed rainfall obtained by hybrid dynamical-statistical approach using the cross-validated EARI from the individual models and their MME. The results show that the rainfalls reconstructed from simulations capture the general features of observed precipitation in East Asia quite well. This study convincingly demonstrates that rainfall prediction skill is considerably improved by using a hybrid dynamical-statistical approach compared to the dynamical forecast alone.

  12. Idealized studies of convective summer precipitation in a cloud-resolving model

    NASA Astrophysics Data System (ADS)

    Schlemmer, Linda; Hohenegger, Cathy; Bretherton, Christopher; Schmidli, Jürg; Schär, Christoph

    2010-05-01

    Climate change is expected to moisten the atmosphere and to intensify the hydrological cycle. In the global mean, precipitation is projected to increase, but for Europe climate models suggest that mean summer precipitation will decrease. However, despite this decrease in mean, heavy precipitation events are projected to occur more frequently. The credibility of these projections, with decreases in mean amounts but increases in peak intensity, is somewhat limited, as convection is parameterized in current climate models due to its small-scale nature. Differences between climate models are especially large in summer, when synoptic-scale forcing is weak and the chosen model formulation has a great influence. Here we investigate the sensitivity of convection to ambient temperature and humidity profiles in a cloud-resolving model (CRM), using a spatial resolution of 500 m - 2 km. The modeling strategy includes an idealized set-up with explicit convection and a full set of parameterizations. The variables are relaxed towards the prescribed profiles and soil conditions, but the relaxation is weak in the lower troposphere and upper soil, such as to allow the development of a diurnal boundary layer. The model is run for 30 days, after which the diurnal cycle approximately repeats itself. Analysis is conducted for the last 15 days of the simulations. A systematic set of experiments with different stratification and humidity profiles is performed. We confirm that the temperature stratification of the environment has a dominant influence on the amount of precipitation by modifying the stability of the atmosphere and thereby the depth and intensity of convection. A more unstable stratification leads to deeper convective clouds and increased amounts of precipitation. In a more stable atmosphere convection remains shallow and precipitation amounts are small. The moisture profile influences the timing and duration of the precipitation period. Simulations with a drier atmosphere

  13. Diagnosis of the secondary circulation of tropical storm Bilis (2006) and the effects of convective systems on its track

    NASA Astrophysics Data System (ADS)

    Yu, Jinhua; Fu, Hao; Tang, Sheng; Sheng, Siwei

    2014-02-01

    We diagnose characteristics of the quasi-balanced flow and secondary circulation (SC) of tropical storm Bilis (2006) using the potential vorticity (PV)- ω inversion method. We further analyze how secondary steering flows associated with mesoscale convective systems affected the track of tropical storm Bilis after it made landfall. The quasi-balanced asymmetric and axisymmetric circulation structures of tropical storm Bilis are represented well by the PV- ω inversion. The magnitude of the nonlinear quasi-balanced vertical velocity is approximately 75% of the magnitude simulated using the Weather Research and Forecasting (WRF) model. The SC of Bilis (2006) contained two strong regions of ascending motion, both of which were located in the southwest quadrant of the storm. The first (150-200 km southwest of the storm center) corresponded to the eyewall region, while the second (approximately 400 km southwest of the storm center) corresponded to latent heat release associated with strong precipitation in major spiral rainbands. The SC was very weak in the northeast quadrant (the upshear direction). Dynamical processes related to the environmental vertical wind shear produced an SC that partially offset the destructive effects of the environmental vertical wind shear (by 20%-25%). This SC consisted of upward motion in the southwest quadrant and subsidence in the northeast quadrant, with airflow oriented from southwest to northeast at high altitudes and from northeast to southwest at lower levels. The inverted secondary zonal and meridional steering flows associated with continuous asymmetric mesoscale convective systems were about -2.14 and -0.7 m s-1, respectively. These steering flows contributed substantially to the zonal (66.15%) and meridional (33.98%) motion of the storm at 0000 UTC 15 July 2006. The secondary steering flow had a significant influence on changing the track of Bilis from southward to northward. The direction of the large-scale meridional steering

  14. Summer insolation is the primary driver for orbital-scale dust storm variability in East Asia

    NASA Astrophysics Data System (ADS)

    Serno, Sascha; Winckler, Gisela; Anderson, Robert F.; Jaccard, Samuel L.; Kienast, Stephanie S.; Haug, Gerald H.

    2016-04-01

    Eolian dust plays an important role in the global climate system through its influence on radiation, albedo and precipitation properties, and through delivering micronutrients like iron to the oceans. Glacial periods of Earth's climate are recognized to be dustier than interglacials, but the conditions leading to greater dust mobilization are poorly defined. We present a high-resolution dust flux record based on 230Th-normalised 4He flux from Ocean Drilling Program (ODP) site 882 in the Subarctic North Pacific covering the last 170,000 years. Today, dust storms in the vast dry regions of East Asia are almost exclusively springtime phenomena, due to a specific set of climate conditions driven by the seasonal evolution of the meridional temperature gradient between high and low latitudes. The dust flux record points to high dust storm activity in East Asia during cold periods, with highest dust flux during Marine Isotope Stages 4 and 5d. We interpret periods of higher dust supply as the result of an expansion of the dust season into the summer, primarily controlled by reduced summer insolation at high latitudes and resulting lower air temperatures in Siberia over orbital timescales. Changes in the extent of the large Northern Hemisphere ice sheets in North America and Fennoscandinavia, and atmospheric teleconnections, act as a secondary control. On millennial timescales, the occurrence of Heinrich Stadials 1 and 11 signals during the last two terminations in Subarctic North Pacific dust records indicates that dust flux variability over millennial timescales was influenced by climate changes in the North Atlantic.

  15. Evaluation and development of satellite inferences of convective storm intensity using combined case study analysis and thunderstorm model simulations

    NASA Technical Reports Server (NTRS)

    Cotton, W. R.; Tripoli, G. J.

    1980-01-01

    Major research accomplishments which were achieved during the first year of the grant are summarized. The research concentrated in the following areas: (1) an examination of observational requirements for predicting convective storm development and intensity as suggested by recent numerical experiments; (2) interpretation of recent 3D numerical experiments with regard to the relationship between overshooting tops and surface wind gusts; (3) the development of software for emulating satellite-inferred cloud properties using 3D cloud model predicted data; and (4) the development of a conceptual/semi-quantitative model of eastward propagating, mesoscale convective complexes forming to the lee of the Rocky Mountains.

  16. A radar-based verification of precipitation forecast for local convective storms

    NASA Astrophysics Data System (ADS)

    Rezacova, Daniela; Sokol, Zbynek; Pesice, Petr

    2007-02-01

    Local flash flood storms with a rapid hydrological response are a real challenge for quantitative precipitation forecasting (QPF). It is relevant to assess space domains, to which the QPF approaches are applicable. In this paper an attempt is made to evaluate the forecasting capability of a high-resolution numerical weather prediction (NWP) model by means of area-related QPF verification. The results presented concern two local convective events, which occurred in the Czech Republic (CR) on 13 and 15 July 2002 and caused local flash floods. We used the LM COSMO model (Lokall Model of the COSMO consortium) adapted to the horizontal resolution of 2.8 km over a model domain covering the CR. The 18 h forecast of convective precipitation was verified by using radar rainfall totals adjusted to the measured rain gauge data. The grid point-related root mean square error (RMSE) value was calculated over a square around the grid point under the assumption that rainfall values were randomly distributed within the square. The forecast accuracy was characterized by the mean RMSE over the whole verification domain. We attempt to show a dependence of both the RMSE field and the mean RMSE on the square size. The importance of a suitable merger between the radar and rain gauge datasets is demonstrated by a comparison between the verification results obtained with and without the gauge adjustment. The application of verification procedure demonstrates uncertainties in the precipitation forecasts. The model was integrated with initial conditions shifted by 0.5° distances. The four verifications, corresponding to the shifts in the four directions, show differences in the resulting QPF, which depend on the size of verification area and on the direction of the shift.

  17. The Impacts of Microphysics and Planetary Boundary Layer Physics on Model Simulations of U.S. Deep South Summer Convection

    NASA Technical Reports Server (NTRS)

    McCaul, Eugene W., Jr.; Case, Jonathan L.; Zavodsky, Bradley; Srikishen, Jayanthi; Medlin, Jeffrey; Wood, Lance

    2014-01-01

    Convection-allowing numerical weather simula- tions have often been shown to produce convective storms that have significant sensitivity to choices of model physical parameterizations. Among the most important of these sensitivities are those related to cloud microphysics, but planetary boundary layer parameterizations also have a significant impact on the evolution of the convection. Aspects of the simulated convection that display sensitivity to these physics schemes include updraft size and intensity, simulated radar reflectivity, timing and placement of storm initi- ation and decay, total storm rainfall, and other storm features derived from storm structure and hydrometeor fields, such as predicted lightning flash rates. In addition to the basic parameters listed above, the simulated storms may also exhibit sensitivity to im- posed initial conditions, such as the fields of soil temper- ature and moisture, vegetation cover and health, and sea and lake water surface temperatures. Some of these sensitivities may rival those of the basic physics sensi- tivities mentioned earlier. These sensitivities have the potential to disrupt the accuracy of short-term forecast simulations of convective storms, and thereby pose sig- nificant difficulties for weather forecasters. To make a systematic study of the quantitative impacts of each of these sensitivities, a matrix of simulations has been performed using all combinations of eight separate microphysics schemes, three boundary layer schemes, and two sets of initial conditions. The first version of initial conditions consists of the default data from large-scale operational model fields, while the second features specialized higher- resolution soil conditions, vegetation conditions and water surface temperatures derived from datasets created at NASA's Short-term Prediction and Operational Research Tran- sition (SPoRT) Center at the National Space Science and Technology Center (NSSTC) in Huntsville, AL. Simulations as

  18. Severe convection and lightning in subtropical South America

    NASA Astrophysics Data System (ADS)

    Rasmussen, Kristen L.; Zuluaga, Manuel D.; Houze, Robert A.

    2014-10-01

    Satellite radar and radiometer data show that subtropical South America has the world's deepest convective storms, robust mesoscale convective systems, and very frequent large hail. We determine severe weather characteristics for the most intense precipitation features seen by satellite in this region. In summer, hail and lightning concentrate over the foothills of western Argentina. Lightning has a nocturnal maximum associated with storms having deep and mesoscale convective echoes. In spring, lightning is maximum to the east in association with storms having mesoscale structure. A tornado alley is over the Pampas, in central Argentina, distant from the maximum hail occurrence, in association with extreme storms. In summer, flash floods occur over the Andes foothills associated with storms having deep convective cores. In spring, slow-rise floods occur over the plains with storms of mesoscale dimension. This characterization of high-impact weather in South America provides crucial information for socioeconomic implications and public safety.

  19. Environmental control of deep convective clouds on Titan: The combined effect of CAPE and wind shear on storm dynamics, morphology, and lifetime

    NASA Astrophysics Data System (ADS)

    Rafkin, Scot C. R.; Barth, E. L.

    2015-04-01

    Titan has deep convective clouds driven by the release of latent from methane condensation. As on Earth, the presence of convective available potential energy (CAPE), which quantifies the amount of energy available through condensation, is required for storms to develop. While CAPE is a requirement for storms, the dynamics, morphology, and longevity of storms on Earth is controlled by both CAPE and wind shear, often expressed as a ratio in the form of the bulk Richardson Number. The impact of CAPE and wind shear on storms in a Titan-like environment are explored through numerical simulation. Model results indicate that Titan storms should respond to changes in the Richardson Number in a manner similar to storms on Earth. Very long-lived storms (>24 h) propagating for 1000 km or more might be possible on Titan when CAPE and wind shear are properly balanced. Some of the simulated storms exhibit dynamics similar to squall lines. Varying amounts of shear in the Titan environment might explain the variety of convective cloud expressions—varying from short-lived single cell storms to longer-lived linear features and large cloud bursts—identified in Cassini orbiter and ground-based observations. The varying amounts and spatial distribution of precipitation, as well as surface winds associated with storms, should have implications on the formation of fluvial and aeolian features and on the exchange of methane with the surface and lakes.

  20. Evaluate the urban effect on summer convective precipitation by coupling a urban canopy model with a Regional Climate Model

    NASA Astrophysics Data System (ADS)

    Liu, Z.; Liu, S.; Xue, Y.; Oleson, K. W.

    2013-12-01

    One of the most significant urbanization in the world occurred in Great Beijing Area of China during the past several decades. The land use and land cover changes modifies the land surface physical characteristics, including the anthropogenic heat and thermo-dynamic conduction. All of those play important roles in the urban regional climate changes. We developed a single layer urban canopy module based on the Community Land Surface Model Urban Module (CLMU). We have made further improvements in the urban module: the energy balances on the five surface conditions are considered separately: building roof, sun side and shade side wall, pervious and impervious land surface. Over each surface, a method to calculate sky view factor (SVF) is developed based on the physically process while most urban models simply provide an empirical value; A new scheme for calculating the latent heat flux is applied on both wall and impervious land; anthropogenic heat is considered in terms of industrial production, domestic wastes, vehicle and air condition. All of these developments improve the accuracy of surface energy balance processing in urban area. The urban effect on summer convective precipitation under the unstable atmospheric condition in the Great Beijing Area was investigated by simulating a heavy rainfall event in July 21st 2012. In this storm, strong meso-scale convective complexes (MCC) brought precipitation of averagely 164 mm within 6 hours, which is the record of past 60 years in the region. Numerical simulating experiment was set up by coupling MCLMU with WRF. Several condition/blank control cases were also set up. The horizontal resolution in all simulations was 2 km. While all of the control results drastically underestimate the urban precipitation, the result of WRF-MCLMU is much closer to the observation though still underestimated. More sensitive experiments gave a preliminary conclusion of how the urban canopy physics processing affects the local precipitation

  1. Automatic differentiation as a tool for sensitivity analysis of a convective storm in a 3-D cloud model

    SciTech Connect

    Park, S.K.; Droegemeier, K.K.; Bischof, C.H.

    1996-10-01

    The ADIFOR automatic differentiation tool is applied to a 3-D storm-scale meteorological model to generate a sensitivity-enhanced code capable of providing derivatives of all model output variables and related diagnostic (derived) parameters as a function of specified control parameters. The tangent linear approximation, applied to a deep convective storm by the first of its kind using a full-physics compressible model, is valid up to 50 min for a 1% water vapor perturbations. The result is very encouraging considering the highly nonlinear and discontinuous properties of solutions. The ADIFOR-generated code has provided valuable sensitivity information on storm dynamics. Especially, it is very efficient and useful for investigating how a perturbation inserted at earlier time propagates through the model variables at later times. However, it is computationally very expensive to be applied to the variational data assimilation, especially for 3-D meteorological models, which potentially have a large number of input variables.

  2. The evolution of convective storms from their footprints on the sea as viewed by synthetic aperture radar from space

    NASA Technical Reports Server (NTRS)

    Atlas, David; Black, Peter G.

    1994-01-01

    SEASAT synthetic aperture radar (SAR) echoes from the sea have previously been shown to be the result of rain and winds produced by convective stroms; rain damps the surface waves and causes ech-free holes, while the diverging winds associated with downdraft generate waves and associated echoes surrounding the holes. Gust fronts are also evident. Such a snapshot from 8 July 1978 has been examined in conjunction with ground-based radar. This leads to the conclusion that the SAR storm footprints resulted from storm processes that occurred up to an hour or more prior to the snapshot. A sequence of events is discerned from the SAR imagery in which new cell growth is triggered in between the converging outflows of two preexisting cells. In turn, the new cell generates a mini-squall line along its expanding gust front. While such phenomena are well known over land, the spaceborne SAR now allows important inferences to be made about the nature and frequency of convective storms over the oceans. The storm effects on the sea have significant implications for spaceborne wind scatterometry and rainfall measurements. Some of the findings herein remain speculative because of the great distance to the Miami weather radar-the only source of corroborative data.

  3. Propagation of Mesoscale Convective Systems over India in the Boreal Summer Monsoon Season

    NASA Astrophysics Data System (ADS)

    Phadtare, J. A.; Bhat, G. S.

    2015-12-01

    With an automated cloud tracking algorithm, we have analysed the propagation of mesoscale convective systems (MCSs) over Indian region in the boreal summer monsoon season (June-September). We used half hourly infrared images of a geostationary satellite KALPANA-I for the study. The data covers four monsoon seasons (2010,12,13,and 14). Mesoscale convective systems (MCSs) over the Indian land show a prominent westward propagation, which is opposite to the lower tropospheric monsoonal westerlies. The mechanism associated with these propagations seems robust, i.e. it appears in all the events. The propagation seems to be a result of internal dynamics of MCS, and not forced by any external agent. The mechanism is prevalent through out the monsoon season, but absent in pre- and post-monsoon season. The zonal convective streaks associated with the large MCSs have a spatial and temporal scales of 1000 km and 1 day respectively, with a westward speed of 18 m/s. These streaks resemble the westward propagating inertial-gravity (WIG) type of wave propagation. Thus, we speculate that, the MCSs over India in the summer monsoon season trigger WIG waves. And the subsequent propagation of MCS is coupled to this wave signal. Most of the large MCSs are associated with the synoptic scale monsoon depressions. Mean propagation of MCSs over Bay of Bengal (BoB) is of more complex nature. There seems to be more than one propagation mechanism which are active over BoB in the summer monsoon season. The selection of propagation mechanism by the BoB MCSs might depend on the phase of diurnal cycle or intra-seasonal oscillation, MCS size, and its location over the bay.

  4. Idealized studies of convective summer precipitation in a cloud-resolving model

    NASA Astrophysics Data System (ADS)

    Schlemmer, L.; Hohenegger, C.; Bretherton, C.; Schär, C.

    2009-04-01

    The expected global temperature increase will lead to an increase of the atmospheric humidity content and an intensification of the hydrological cycle. In the global mean, precipitation is projected to increase, but climate models suggest that mean summer precipitation over Europe will decrease. However, despite this decrease in mean, heavy precipitation events are projected to occur more frequently. Changes in extreme precipitation are important to understand, since they pose an enormous threat. Especially in mountainous regions like the Alps, they often imply great socio-economic impacts. The credibility of these projections, with decreases in mean amounts but increases in peak intensity, is somewhat limited, as convection is parameterized in current climate models due to its small-scale nature. Simulations of present-day and future climate performed with a range of regional climate models in the context of the PRUDENCE project have revealed a large spread of the amount and distribution of precipitation. Differences between climate models are especially large in summer, when synoptic-scale forcing is weak and the chosen model formulation has a great influence. The increasing computer power allows the use with finer grid-spacing in the horizontal, as well as in the vertical direction. The increased resolution enables a more realistic representation of topography and surface fields. Most importantly, the finer grid and the release of the hydrostatic assumption render possible an explicit treatment of convective processes. Here we investigate the response of convection to future climate changes in a cloud-resolving model (CRM) using an extremely high spatial resolution of 1- 2 km. This approach is still far too expensive for standard climate scenarios, but it is becoming feasible for process studies. Using a CRM in an idealized setting, we are trying to infer the response of convection to altered temperature and moisture profiles. The modeling strategy includes a

  5. Enhancement of seasonal prediction of East Asian summer rainfall related to the western tropical Pacific convection

    NASA Astrophysics Data System (ADS)

    Lee, D. Y.; Ahn, J. B.; Yoo, J. H.

    2014-12-01

    The prediction skills of climate model simulations in the western tropical Pacific (WTP) and East Asian region are assessed using the retrospective forecasts of seven state-of-the-art coupled models and their multi-model ensemble (MME) for boreal summers (June-August) during the period 1983-2005, along with corresponding observed and reanalyzed data. The prediction of summer rainfall anomalies in East Asia is difficult, while the WTP has a strong correlation between model prediction and observation. We focus on developing a new approach to further enhance the seasonal prediction skill for summer rainfall in East Asia and investigate the influence of convective activity in the WTP on East Asian summer rainfall. By analyzing the characteristics of the WTP convection, two distinct patterns associated with El Niño-Southern Oscillation (ENSO) developing and decaying modes are identified. Based on the multiple linear regression method, the East Asia Rainfall Index (EARI) is developed by using the interannual variability of the normalized Maritime continent-WTP indices (MPIs), as potentially useful predictors for rainfall prediction over East Asia, obtained from the above two main patterns. For East Asian summer rainfall, the EARI has superior performance to the East Asia summer monsoon index (EASMI) or each MP index (MPI). Therefore, the regressed rainfall from EARI also shows a strong relationship with the observed East Asian summer rainfall pattern. In addition, we evaluate the prediction skill of the East Asia reconstructed rainfall obtained by statistical-empirical approach using the cross-validated EARI from the individual models and their MME. The results show that the rainfalls reconstructed from simulations capture the general features of observed precipitation in East Asia quite well. This study convincingly demonstrates that rainfall prediction skill is considerably improved by using the statistical-empirical method compared to the dynamical models

  6. Wet scavenging of soluble gases in DC3 deep convective storms using WRF-Chem simulations and aircraft observations

    NASA Astrophysics Data System (ADS)

    Bela, Megan M.; Barth, Mary C.; Toon, Owen B.; Fried, Alan; Homeyer, Cameron R.; Morrison, Hugh; Cummings, Kristin A.; Li, Yunyao; Pickering, Kenneth E.; Allen, Dale J.; Yang, Qing; Wennberg, Paul O.; Crounse, John D.; St. Clair, Jason M.; Teng, Alex P.; O'Sullivan, Daniel; Huey, L. Gregory; Chen, Dexian; Liu, Xiaoxi; Blake, Donald R.; Blake, Nicola J.; Apel, Eric C.; Hornbrook, Rebecca S.; Flocke, Frank; Campos, Teresa; Diskin, Glenn

    2016-04-01

    We examine wet scavenging of soluble trace gases in storms observed during the Deep Convective Clouds and Chemistry (DC3) field campaign. We conduct high-resolution simulations with the Weather Research and Forecasting model with Chemistry (WRF-Chem) of a severe storm in Oklahoma. The model represents well the storm location, size, and structure as compared with Next Generation Weather Radar reflectivity, and simulated CO transport is consistent with aircraft observations. Scavenging efficiencies (SEs) between inflow and outflow of soluble species are calculated from aircraft measurements and model simulations. Using a simple wet scavenging scheme, we simulate the SE of each soluble species within the error bars of the observations. The simulated SEs of all species except nitric acid (HNO3) are highly sensitive to the values specified for the fractions retained in ice when cloud water freezes. To reproduce the observations, we must assume zero ice retention for formaldehyde (CH2O) and hydrogen peroxide (H2O2) and complete retention for methyl hydrogen peroxide (CH3OOH) and sulfur dioxide (SO2), likely to compensate for the lack of aqueous chemistry in the model. We then compare scavenging efficiencies among storms that formed in Alabama and northeast Colorado and the Oklahoma storm. Significant differences in SEs are seen among storms and species. More scavenging of HNO3 and less removal of CH3OOH are seen in storms with higher maximum flash rates, an indication of more graupel mass. Graupel is associated with mixed-phase scavenging and lightning production of nitrogen oxides (NOx), processes that may explain the observed differences in HNO3 and CH3OOH scavenging.

  7. Relationships between convective storms and their environment in AVE IV determined from a three-dimensional subsynoptic-scale, trajectory model

    NASA Technical Reports Server (NTRS)

    Wilson, G. S.

    1977-01-01

    The paper describes interrelationships between synoptic-scale and convective-scale systems obtained by following individual air parcels as they traveled within the convective storm environment of AVE IV. (NASA's fourth Atmospheric Variability Experiment, AVE IV, was a 36-hour study in April 1975 of the atmospheric variability and structure in regions of convective storms.) A three-dimensional trajectory model was used to calculate parcel paths, and manually digitized radar was employed to locate convective activity of various intensities and to determine those trajectories that traversed the storm environment. Spatial and temporal interrelationships are demonstrated by reference to selected time periods of AVE IV which contain the development and movement of the squall line in which the Neosho tornado was created.

  8. Summer African Dust and Florida Thunder Storms: Are CRYSTAL-FACE Anvils Typical of the Subtropics?

    NASA Astrophysics Data System (ADS)

    Sassen, K.; Campbell, J. R.; Prospero, J. M.

    2003-12-01

    The Florida peninsula can be viewed as an outdoor laboratory for the study of the indirect effects of aerosols on the properties of deep convective clouds, and the possible subsequent impact on precipitation. Depending on the seasonal weather patters affecting the area, sources of aerosols can be continental, smoke-produced, oceanic, and, as long known, of Saharan Desert origin. During the recent CRYSTAL-FACE field campaign, a variety of in situ and remote sensing evidence shows that after transport across the mid-Atlantic Ocean, episodes of African dust were widespread in the region. This is a well-known summer-time phenomenon. In one study using aircraft ice nuclei (IN) data and ground-based polarization lidar measurements, the dust was observed to induce the glaciation of a slightly (about -5.0 to -8.0 degrees C) supercooled altocumulus cloud. Extrapolating the finding that African dust particles are especially active IN, it follows that the ingestion of boundary-layer Saharan aerosol could have a strong potential for modifying the microphysical content, dynamics and precipitation of summer thunderstorms in southern Florida. In the current study, we will attempt to identify connections between the characteristics of the intensively-studied thunderstorms and the nature of the dominant aerosols involved in cloud particle formation. As a first step, the near-continuous data record from the Micropulse Lidar, supplemented by Polarization Diversity Lidar data, will be used to monitor aerosol conditions. Backtrack and satellite analyzes, along with the University of Miami surface aerosol sampling record, will identify their source and likely cloud particle forming characteristics. The final stage of this research will search for correlations in in situ-derived cloud microphysical properties such as ice crystal concentration and type. If such connections are found, it must be recognized that the CRYSTAL-FACE dataset may not be representative of subtropical thunderstorms

  9. Sensitivity of summer ensembles of fledgling superparameterized U.S. mesoscale convective systems to cloud resolving model microphysics and grid configuration

    DOE PAGES

    Elliott, Elizabeth J.; Yu, Sungduk; Kooperman, Gabriel J.; Morrison, Hugh; Wang, Minghuai; Pritchard, Michael S.

    2016-05-01

    The sensitivities of simulated mesoscale convective systems (MCSs) in the central U.S. to microphysics and grid configuration are evaluated here in a global climate model (GCM) that also permits global-scale feedbacks and variability. Since conventional GCMs do not simulate MCSs, studying their sensitivities in a global framework useful for climate change simulations has not previously been possible. To date, MCS sensitivity experiments have relied on controlled cloud resolving model (CRM) studies with limited domains, which avoid internal variability and neglect feedbacks between local convection and larger-scale dynamics. However, recent work with superparameterized (SP) GCMs has shown that eastward propagating MCS-likemore » events are captured when embedded CRMs replace convective parameterizations. This study uses a SP version of the Community Atmosphere Model version 5 (SP-CAM5) to evaluate MCS sensitivities, applying an objective empirical orthogonal function algorithm to identify MCS-like events, and harmonizing composite storms to account for seasonal and spatial heterogeneity. A five-summer control simulation is used to assess the magnitude of internal and interannual variability relative to 10 sensitivity experiments with varied CRM parameters, including ice fall speed, one-moment and two-moment microphysics, and grid spacing. MCS sensitivities were found to be subtle with respect to internal variability, and indicate that ensembles of over 100 storms may be necessary to detect robust differences in SP-GCMs. Furthermore, these results emphasize that the properties of MCSs can vary widely across individual events, and improving their representation in global simulations with significant internal variability may require comparison to long (multidecadal) time series of observed events rather than single season field campaigns.« less

  10. Airborne quantification of upper tropospheric NOx production from lightning in deep convective storms over the United States Great Plains

    NASA Astrophysics Data System (ADS)

    Pollack, I. B.; Homeyer, C. R.; Ryerson, T. B.; Aikin, K. C.; Peischl, J.; Apel, E. C.; Campos, T.; Flocke, F.; Hornbrook, R. S.; Knapp, D. J.; Montzka, D. D.; Weinheimer, A. J.; Riemer, D.; Diskin, G.; Sachse, G.; Mikoviny, T.; Wisthaler, A.; Bruning, E.; MacGorman, D.; Cummings, K. A.; Pickering, K. E.; Huntrieser, H.; Lichtenstern, M.; Schlager, H.; Barth, M. C.

    2016-02-01

    The reported range for global production of nitrogen oxides (NOx = NO + NO2) by lightning remains large (e.g., 32 to 664 mol NOx flash-1), despite incorporating results from over 30 individual laboratory, theoretical, and field studies since the 1970s. Airborne and ground-based observations from the Deep Convective Clouds and Chemistry experiment in May and June 2012 provide a new data set for calculating moles of NOx produced per lightning flash, P(NOx), in thunderstorms over the United States Great Plains. This analysis utilizes a combination of in situ observations of storm inflow and outflow from three instrumented aircraft, three-dimensional spatial information from ground-based radars and satellite observations, and spatial and temporal information for intracloud and cloud-to-ground lightning flashes from ground-based lightning mapping arrays. Evaluation of two analysis methods (e.g., a volume-based approach and a flux-based approach) for converting enhancements in lightning-produced NOx from volume-based mixing ratios to moles NOx flash-1 suggests that both methods equally approximate P(NOx) for storms with elongated anvils, while the volume-based approach better approximates P(NOx) for storms with circular-shaped anvils. Results from the more robust volume-based approach for three storms sampled over Oklahoma and Colorado during DC3 suggest a range of 142 to 291 (average of 194) moles NOx flash-1 (or 117-332 mol NOx flash-1 including uncertainties). Although not vastly different from the previously reported range for storms occurring in the Great Plains (e.g., 21-465 mol NOx flash-1), results from this analysis of DC3 storms offer more constrained upper and lower limits for P(NOx) in this geographical region.

  11. Measurement of Attenuation with Airborne and Ground-Based Radar in Convective Storms Over Land and Its Microphysical Implications

    NASA Technical Reports Server (NTRS)

    Tian, Lin; Heymsfield, G. M.; Srivastava, R. C.; Starr, D. OC. (Technical Monitor)

    2001-01-01

    Observations by the airborne X-band Doppler radar (EDOP) and the NCAR S-band polarimetric (S-POL) radar from two field experiments are used to evaluate the Surface ref'ercnce technique (SRT) for measuring the path integrated attenuation (PIA) and to study attenuation in deep convective storms. The EDOP, flying at an altitude of 20 km, uses a nadir beam and a forward pointing beam. It is found that over land, the surface scattering cross-section is highly variable at nadir incidence but relatively stable at forward incidence. It is concluded that measurement by the forward beam provides a viable technique for measuring PIA using the SRT. Vertical profiles of peak attenuation coefficient are derived in vxo deep convective storms by the dual-wavelength method. Using the measured Doppler velocity, the reflectivities at. the two wavelengths, the differential reflectivity and the estimated attenuation coefficients, it is shown that: supercooled drops and dry ice particles probably co-existed above the melting level in regions of updraft, that water-coated partially melted ice particles probably contributed to high attenuation below the melting level, and that the data are not readil explained in terms of a gamma function raindrop size distribution.

  12. Measurement of Attenuation with Airborne and Ground-Based Radar in Convective Storms Over Land Its Microphysical Implications

    NASA Technical Reports Server (NTRS)

    Tian, Lin; Heymsfield, G. M.; Srivastava, R. C.; O'C.Starr, D. (Technical Monitor)

    2001-01-01

    Observations by the airborne X-band Doppler radar (EDOP) and the NCAR S-band polarimetric (S-Pol) radar from two field experiments are used to evaluate the surface reference technique (SRT) for measuring the path integrated attenuation (PIA) and to study attenuation in deep convective storms. The EDOP, flying at an altitude of 20 km, uses a nadir beam and a forward pointing beam. It is found that over land, the surface scattering cross-section is highly variable at nadir incidence but relatively stable at forward incidence. It is concluded that measurement by the forward beam provides a viable technique for measuring PIA using the SRT. Vertical profiles of peak attenuation coefficient are derived in two deep convective storms by the dual-wavelength method. Using the measured Doppler velocity, the reflectivities at the two wavelengths, the differential reflectivity and the estimated attenuation coefficients, it is shown that: supercooled drops and (dry) ice particles probably co-existed above the melting level in regions of updraft, that water-coated partially melted ice particles probably contributed to high attenuation below the melting level.

  13. Investigation into the impact of storms on sustaining summer primary productivity in the Sub-Antarctic Ocean

    NASA Astrophysics Data System (ADS)

    Nicholson, Sarah-Anne; Lévy, Marina; Llort, Joan; Swart, Sebastiaan; Monteiro, Pedro M. S.

    2016-09-01

    In the Sub-Antarctic Ocean elevated phytoplankton biomass persists through summer at a time when productivity is expected to be low due to iron limitation. Biological iron recycling has been shown to support summer biomass. In addition, we investigate an iron supply mechanism previously unaccounted for in iron budget studies. Using a 1-D biogeochemical model, we show how storm-driven mixing provides relief from phytoplankton iron limitation through the entrainment of iron beneath the productive layer. This effect is significant when a mixing transition layer of strong diffusivities (kz > 10-4 m2 s-1) is present beneath the surface-mixing layer. Such subsurface mixing has been shown to arise from interactions between turbulent ocean dynamics and storm-driven inertial motions. The addition of intraseasonal mixing yielded increases of up to 60% in summer primary production. These results stress the need to acquire observations of subsurface mixing and to develop the appropriate parameterizations of such phenomena for ocean-biogeochemical models.

  14. Changes in monoterpene mixing ratios during summer storms in rural New Hampshire (USA)

    USGS Publications Warehouse

    Haase, K.B.; Jordan, C.; Mentis, E.; Cottrell, L.; Mayne, H.R.; Talbot, R.; Sive, B.C.

    2011-01-01

    Monoterpenes are an important class of biogenic hydrocarbons that influence ambient air quality and are a principle source of secondary organic aerosol (SOA). Emitted from vegetation, monoterpenes are a product of photosynthesis and act as a response to a variety of environmental factors. Most parameterizations of monoterpene emissions are based on clear weather models that do not take into account episodic conditions that can drastically change production and release rates into the atmosphere. Here, the ongoing monoterpene dataset from the rural Thompson Farm measurement site in Durham, New Hampshire is examined in the context of a set of known severe storm events. While some storm systems had a negligible influence on ambient monoterpene mixing ratios, the average storm event increased mixing ratios by 0.59 ?? 0.21 ppbv, a factor of 93 % above pre-storm levels. In some events, mixing ratios reached the 10's of ppbv range and persisted overnight. These mixing ratios correspond to increases in the monoterpene emission rate, ranging from 120 to 1240 g km-2 h -1 compared to an estimated clear weather rate of 116 to 193 g km-2 h-1. Considering the regularity of storm events over most forested areas, this could be an important factor to consider when modeling global monoterpene emissions and their resulting influence on the formation of organic aerosols. ?? 2011 Author(s).

  15. Changes in monoterpene mixing ratios during summer storms in rural New Hampshire (USA)

    USGS Publications Warehouse

    Haase, Karl B.; Jordan, C.; Mentis, E.; Cottrell, L.; Mayne, H.R.; Talbot, R.; Sive, B.C.

    2011-01-01

    Monoterpenes are an important class of biogenic hydrocarbons that influence ambient air quality and are a principle source of secondary organic aerosol (SOA). Emitted from vegetation, monoterpenes are a product of photosynthesis and act as a response to a variety of environmental factors. Most parameterizations of monoterpene emissions are based on clear weather models that do not take into account episodic conditions that can drastically change production and release rates into the atmosphere. Here, the monoterpene dataset from the rural Thompson Farm measurement site in Durham, New Hampshire is examined in the context of a set of known severe storm events. While some storm systems had a negligible influence on ambient monoterpene mixing ratios, the average storm event increased mixing ratios by 0.59 ?? 0.21 ppbv, a factor of 93% above pre-storm levels. In some events, mixing ratios reached the 10's of ppbv range and persisted overnight. These mixing ratios correspond to increases in the monoterpene emission rate, ranging from 120 to 1240 g km-2 h -1 compared to an estimated clear weather rate of 116 to 193 g km-2 h-1. Considering the regularity of storm events over most forested areas, this could be an important factor to consider when modeling global monoterpene emissions and their resulting influence on the formation of organic aerosols.

  16. The Effect of Dust Storm on Deep Convection over the Tropical North Atlantic

    NASA Astrophysics Data System (ADS)

    Wong, S.; Dessler, A. E.

    2004-12-01

    The effect of the Saharan mineral dust on deep convection over the tropical North Atlantic were investigated by anlayzing Moderate Resolution Imaging Spectroradiometer (MODIS) level-2 retrievals. Brightness temperature at 11 μ m were used to indicate the occurrence of deep convection and the tropospheric aerosol loading was represented by the aerosol optical thickness (AOT) at 0.55 μ m. Probability distribution functions (PDFs) of the brightness temperature were constructed for a region offshore the African west coast for August-September 2002, when dust was frequently blown off the Saharan desert and transported across the North Atlantic. For conditions of high aerosol loading (AOT > 0.8), the frequency of brightness temperatures less than 230 K was reduced by a factor of 5-6 from the value associated with conditions of low aerosol loading (AOT < 0.5). The atmospheric effect of the aerosols lasts at least one day after the passage of the aerosols.

  17. High resolution radiometric measurements of convective storms during the GATE experiment

    NASA Technical Reports Server (NTRS)

    Fowler, G.; Lisa, A. S.

    1976-01-01

    Using passive microwave data from the NASA CV-990 aircraft and radar data collected during the Global Atmospheric Research Program Atlantic Tropical Experiment (GATE), an empirical model was developed relating brightness temperatures sensed at 19.35 GHz to surface rainfall rates. This model agreed well with theoretical computations of the relationship between microwave radiation and precipitation in the tropics. The GATE aircraft microwave data was then used to determine the detailed structure of convective systems. The high spatial resolution of the data permitted identification of individual cells which retained unique identities throughout their lifetimes in larger cloud masses and allowed analysis of the effects of cloud merger.

  18. Overview of ESSL's severe convective storms research using the European Severe Weather Database ESWD

    NASA Astrophysics Data System (ADS)

    Dotzek, Nikolai; Groenemeijer, Pieter; Feuerstein, Bernold; Holzer, Alois M.

    Severe thunderstorms constitute a major weather hazard in Europe, with an estimated total damage of 5-8 billion euros each year nowadays. Even though there is an upward trend in damage due to increases in vulnerability and possibly also due to climate change impacts, a pan-European database of severe thunderstorm reports in a homogeneous data format did not exist until a few years ago. The development of this European Severe Weather Database (ESWD) provided the final impetus for the establishment of the European Severe Storms Laboratory (ESSL) as a non-profit research organisation in 2006, after having started as an informal network in 2002. Our paper provides an overview of the first research results that have been achieved by ESSL. We start by outlining the reporting practice and quality-control procedure for the database, which has been enhanced by a major software upgrade in the fall of 2008. It becomes apparent that the state of reporting converges to a realistic description of the severe storms climatology, corroborating, for instance, earlier estimates of tornado occurrence in Europe. Nevertheless, a further rise in the number of reported events must be expected, even without the presence of any physical trends. The European tornado and damaging wind intensity distributions as a function of the Fujita scale are quantitatively similar to long-term distributions from the USA, except for a strong underreporting of weak events (F0) that still persists in Europe. In addition, the ESSL has recently proposed a new wind speed scale, the Energy- or " E-scale" which is linked to physical quantities and can be calibrated. Finally, we demonstrate the large potential of ESWD data use for forecast or nowcasting/warning verification purposes.

  19. Radar Observation of Large Attenuation in Convective Storms: Implications for the Dropsize Distribution

    NASA Technical Reports Server (NTRS)

    Tian, Lin; Heymsfield, G. M.; Srivastava, R. C.

    2000-01-01

    Airborne meteorological radars typically operate at attenuating wavelengths. The path integrated attenuation (PIA) can be estimated using the surface reference technique (SRT). In this method, an initial value is determined for the radar cross section of the earth surface in a rain-free area in relatively close proximity to the rain cloud. During subsequent observations of precipitation any decrease 'in the observed surface cross section from the reference value s assumed to be a result of the two-way attenuation along the propagation path. In this paper we present selected instances of high PIA observed over land by an airborne radar. The observations were taken in Brazil and Florida during TRMM (Tropical Rainfall Measurement Mission) field campaigns. We compared these observations with collocated and nearly simultaneous ground-based radar observations by an S-band radar that is not subject to significant attenuation. In this preliminary evaluation, a systematic difference in the attenuation in the two storms is attributed to a difference in the raindrop size distributions; this is supported by observations of ZDR (differential reflectivity).

  20. Three-Dimensional Simulation of a Convective Storm: Sensitivity Studies on Subgrid Parameterization and Spatial Resolution.

    NASA Astrophysics Data System (ADS)

    Redelsperger, J. L.; Sommeria, G.

    1986-11-01

    This article presents the main features of a three-dimensional model for deep convection developed with special care given to the formulation of subgrid turbulent processes. It explicitly simulates the dynamics of turbulent eddies, including condensation and precipitation processes. Second-order moments are expressed as a function of the grid-averaged field of variables and of a prognostic turbulent kinetic energy. The formulation includes a simple statistical treatment of subgrid condensation and subgrid conversion of cloud water into rain water. The coherence and relative importance of the various closure hypotheses are tested in an idealized case of precipitating cloud.Results indicate the extent that features of the computed field are dependent on hypotheses used in the turbulence closure, choice of the basic turbulent variables, and formulation of the second-order moments. Significant benefits are obtained from the use of variables that are conserved in the condensation process. The computation of grid-scale condensation and precipitation is mostly dependent on the hypotheses made respectively for subgrid condensation and precipitation. Finally, it is shown that an advanced subgrid turbulence parameterization can partially compensate for the effects of a low spatial resolution.

  1. Direct observations of the role of convection electric field in the formation of a polar tongue of ionization from storm enhanced density

    NASA Astrophysics Data System (ADS)

    Thomas, E. G.; Baker, J. B. H.; Ruohoniemi, J. M.; Clausen, L. B. N.; Coster, A. J.; Foster, J. C.; Erickson, P. J.

    2013-03-01

    examine the relationship of convection electric fields to the formation of a polar cap tongue of ionization (TOI) from midlatitude plumes of storm enhanced density (SED). Observations from the geomagnetic storm on 26-27 September 2011 are presented for two distinct SED events. During an hour-long period of geomagnetic activity driven by a coronal mass ejection, a channel of high-density F region plasma was transported from the dayside subauroral ionosphere and into the polar cap by enhanced convection electric fields extending to middle latitudes. This TOI feature was associated with enhanced HF backscatter, indicating that it was the seat of active formation of small-scale irregularities. After the solar wind interplanetary magnetic field conditions quieted and the dayside convection electric fields retreated to higher latitudes, an SED plume was observed extending to, but not entering, the dayside cusp region. This prominent feature in the distribution of total electron content (TEC) persisted for several hours and elongated in magnetic local time with the rotation of the Earth. No ionospheric scatter from SuperDARN radars was observed within this SED region. The source mechanism (enhanced electric fields) previously drawing the plasma from midlatitudes and into the polar cap as a TOI was no longer active, resulting in a fossil feature. We thus demonstrate the controlling role exercised by the convection electric field in generating a TOI from midlatitude SED.

  2. Anomalous convective activity over sub-tropical east Pacific during 2015 and associated boreal summer monsoon teleconnections

    NASA Astrophysics Data System (ADS)

    Mujumdar, Milind; Sooraj, K. P.; Krishnan, R.; Preethi, B.; Joshi, Manish K.; Varikoden, Hamza; Singh, Bhupendra B.; Rajeevan, M.

    2016-08-01

    The eastern Pacific Ocean received a record highest number of sub-tropical convective activities during boreal summer (June-September) of 2015, since last four decades. The associated rainfall distribution was also atypical with anomalously enhanced rainfall extending from equator to sub-tropical central-eastern Pacific. The present analysis reveals a pronounced meridional sea surface temperature (SST) gradient across central-eastern Pacific, with the mean SST exceeding 28 °C over sub-tropical north Pacific, setting up favorable conditions for these enhanced convective activities. It is found that these anomalous features promoted northward spanning of westerly anomalies and drastically modified the east-west circulation over sub-tropical north Pacific. This seems to induce large-scale subsidence over the off-equatorial monsoon regions of south and south-east Asia, thus constituting an east-west asymmetry over sub-tropical Indo-Pacific region. Based on our observational study, it can be concluded that the sub-tropical convective activities over east Pacific may play a pivotal role in mediating the Pacific-monsoon teleconnection through the unexplored meridional SST gradient across Pacific.

  3. Summer season land cover—Convective cloud associations for the midwest U.S. “Corn Belt”

    NASA Astrophysics Data System (ADS)

    Carleton, Andrew M.; Adegoke, Jimmy; Allard, Jason; Arnold, David L.; Travis, David J.

    Human-induced land cover modifications impact the planetary boundary layer's (PBL) thermal and moisture regimes on mesoscales. We investigate the association of croplands, forest, and the crop-forest “boundary” (CFB) with convective-cloud development (timing, amount) for three target areas (TAs) in the U.S. Midwest “Corn Belt”, during the summer seasons (JJA) 1991-98. For each land cover, hourly satellite-retrieved albedo and cloud-top temperature values are composited for three classes of mid-tropospheric synoptic circulation. On days with the strongest anticyclonicity, there are no consistent differences in convection related to land cover type: cloud development is regionalized and tied primarily to synoptic conditions. However, on days having weaker anticyclonicity the CFB is the dominant site of free convection, suggesting that Non-Classical Mesoscale Circulations (NCMCs) between cropped and adjacent forest areas may operate when reduced subsidence in the mid-troposphere does not effectively cap the PBL. Index terms: Land/atmosphere interactions (3322), Mesoscale meteorology (3329), Climate dynamics (1620), Anthropogenic effects (1803).

  4. How do geomorphic effects of rainfall vary with storm type and spatial scale in a post-fire landscape?

    NASA Astrophysics Data System (ADS)

    Kampf, Stephanie K.; Brogan, Daniel J.; Schmeer, Sarah; MacDonald, Lee H.; Nelson, Peter A.

    2016-11-01

    In post-fire landscapes, increased runoff and soil erosion can cause rapid geomorphic change. We examined how different types of rainfall events in 2013 affected hillslope-scale erosion and watershed-scale channel change in two 14-16 km2 watersheds within the 2012 High Park Fire burn area in northern Colorado, USA. The first set of rainfall events was a sequence of 12 short, spatially variable summer convective rain storms, and the second was a > 200 mm week-long storm in September. We compared rainfall characteristics, hillslope sediment yields, stream stage, and channel geometry changes from the summer storms to those from the September storm. The summer storms had a wide range of rainfall intensities, and each storm produced erosion primarily in one study watershed. The September storm rainfall had less spatial variability, covered both watersheds, and its total rainfall depth was 1.5 to 2.5 times greater than the total summer rainfall. Because rainfall intensities were highest during some summer storms, average hillslope sediment yields were higher for summer storms (6 Mg ha- 1) than for the September storm (3 Mg ha- 1). Maximum storm rainfall intensities were good predictors of hillslope sediment yield, but sediment yield correlated most strongly with total depths of rainfall exceeding 10-30 mm h- 1 intensity thresholds. The combined summer storms produced relatively small changes in mean channel bed elevation and cross section area, with no clear pattern of incision or aggradation. In contrast, the sustained rain across the entire study area during the September storm led to extensive upstream incision and downstream aggradation. Because of different spatial coverage of storms, summer storms produced more total hillslope erosion, whereas the September storm produced the greatest total channel changes. At both scales, high intensity rainfall above a threshold was responsible for inducing most of the geomorphic change.

  5. Improving the Knowledge of Summer Monsoon Storm Genesis on the Mumbai Region

    NASA Astrophysics Data System (ADS)

    Lomazzi, M.; Entekhabi, D.; Pinto, J. G.; Roth, G.; Rudari, R.

    2009-09-01

    Over the Indian Subcontinent, almost 75% of the annual precipitation is expected to fall during the South Asia Monsoon (SAM) season, conventionally defined between June 1 and September 30. While precipitation patterns show a very strong spatial heterogeneity, the maximum annual values (which may exceed 4000 mm) occur in the Western Coast of Indian Peninsula. This is mainly associated with orographic forcing, in particular of the Western Ghats and the Ganges and Brahmaputra valleys. Extreme rainfall events during the SAM season may be particularly intense and long-lasting, causing great damages both in terms of life and economic losses. We aim at identifying large-scale meteorological patterns associated with the triggering of extreme rainfall events affecting the Mumbai area (approximately 18-20°N, 72.5-73.5°E), a very highly populated region (around 20 million people), during the SAM season. Seventy years of daily rainfall data are analyzed and compared to a database of damage-causing precipitations. Event days are selected with a twin-threshold function related to daily rainfall height and soil moisture content. To detect typical large-scale features, event days are compared to non-event days by analyzing MSLP, SST, and vertical wind profiles. Further, the storm-related processes are analyzed with moisture sources (via backtracing) and moisture flux convergence fields. First results on selected event days show that they are typically characterized by remote moisture sources (from S-W Arabian Sea) and increased lower level westerly winds which cause enhanced moisture flux convergence, leading to precipitable water’s enhancement.

  6. Convection and overshielding electric fields in the global ionosphere as observed with magnetometers and SuperDARN during the geomagnetic storm on 14-15 December 2006

    NASA Astrophysics Data System (ADS)

    Kikuchi, T.; Ebihara, Y.; Hashimoto, K. K.; Kataoka, R.; Hori, T.; Watari, S.; Nishitani, N.

    2008-12-01

    The convection electric field penetrates to the equatorial ionosphere with no significant shielding effects during the DP2 fluctuation event of period of 30 - 60 min (Nishida, 1968) and during the storm main phase continuing over several hours (Huang et al., 2007). On the other hand, shielding becomes effective during the substorm growth phase (Somajajulu et al., 1987; Kikuchi et al., 2000) and even during storm main phase (Kikuchi et al., 2008). The well-developed shielding electric field results in an overshielding at the beginning of the recovery phase of storm/substorms (Kikuchi et al., 2003, 2008). Thus, the electric field manifests complex features at mid-equatorial latitudes, which is not determined only by the solar wind electric field but strongly controlled by magnetospheric processes such as the ring current. To reveal comparative roles of the convection and overshielding electric fields and in what condition the overshielding occurs at mid-equatorial latitudes, we analyzed the geomagnetic storm on 14-15 December, 2006, characterized by the quasi-periodic DP2 fluctuation of 30 min period at the beginning of the storm. We used magnetometer data from mid- equatorial latitudes to detect magnetic signatures due to the electric field originating in the magnetosphere, and used the SuperDARN data to identify electric fields associated with the solar wind dynamo (Region-1 FAC) and the ring current (R2 FAC). We further calculated an electric potential pattern caused by the R1 and R2 FACs with the comprehensive ring current model (CRCM) to better understand the SuperDARN convection pattern. First we show that the DP2 fluctuation was caused by alternating eastward (e-EJ) and westward currents (w-EJ) in the equatorial ionosphere, which were caused by the southward and northward IMF, respectively. We further show that the e-EJ was associated with the large-scale two-cell convection vortices, while the w-EJ accompanied a reverse flow equatorward of the two

  7. The influence of Nunataks on atmospheric boundary layer convection during summer in Dronning Maud Land, Antarctica

    NASA Astrophysics Data System (ADS)

    Stenmark, Aurora; Hole, Lars Robert; Voss, Paul; Reuder, Joachim; Jonassen, Marius O.

    2014-06-01

    The effects of nunataks on temperature profiles and wind patterns are studied using simulations from the Weather Research and Forecasting model. Simulations are compared to hourly observations from an automatic weather station located at the Troll Research Station in Dronning Maud Land. Areas of bare ground have been implemented in the model, and the simulations correspond well with meteorological measurements acquired during the 4 day simulation period. The nunataks are radiatively heated during daytime, and free convection occurs in the overlying atmospheric boundary layer. The inflow below the updraft forces strong horizontal convergence at the surface, whereas weaker divergence appears aloft. In a control run with a completely ice-covered surface, the convection is absent. In situ observations carried out by a remotely controlled balloon and a small model airplane compare well with model temperature profiles, but these are only available over the ice field upwind to the nunatak.

  8. Characterization of mesoscale convective systems over the eastern Pacific during boreal summer

    NASA Astrophysics Data System (ADS)

    Berthet, Sarah; Rouquié, Bastien; Roca, Rémy

    2015-04-01

    The eastern Pacific Ocean is one of the most active tropical disturbances formation regions on earth. This preliminary study is part of a broader project that aims to investigate how mesoscale convective systems (MCS) may be related to these synoptic disturbances with emphasis on local initiation of tropical depressions. As a first step, the main characteristics of the MCS over the eastern Pacific are documented with the help of the recently developed TOOCAN tracking algorithm (Fiolleau and Roca, 2013) applied to the infrared satellite imagery data from GOES-W and -E for the period JJAS 2012-2014. More specifically, the spatial distribution of the MCS population, the statistics of their spatial extensions and durations, as well as their trajectories and propagation speeds are summarized. In addition the environment of the MCS will be investigated using various Global Precipitation Mission datasets and the Megha-Tropiques/SAPHIR humidity microwave sounder derived products. Reference: Fiolleau T. and R. Roca, (2013), An Algorithm For The Detection And Tracking Of Tropical Mesoscale Convective Systems Using Infrared Images From Geostationary Satellite, Transactions on Geoscience and Remote Sensing, doi: 10.1109/TGRS.2012.2227762.

  9. The Impact on Simulated Storm Structure and Intensity of Variations in the Lifted Condensation Level and the Level of Free Convection

    NASA Technical Reports Server (NTRS)

    McCaul, Eugene W., Jr.; Cohen, Charles; Arnold, James E. (Technical Monitor)

    2001-01-01

    The sensitivities of convective storm structure and intensity to changes in the altitudes of the prestorm environmental lifted condensation level and level of free convection axe studied using a full-physics three-dimensional cloud model. Matrices of simulations are conducted for a range of LCL=LFC altitudes, using a single moderately-sheared curved hodograph trace in conjunction with 1 convective available potential energy values of either 800 or 2000 J/kg, with the matrices consisting of all four combinations of two distinct choices of buoyancy and shear profile shape. For each value of CAPE, the LCL=LFC altitudes are also allowed to vary in a series of simulations based on the most highly compressed buoyancy and shear profiles for that CAPE, with the environmental buoyancy profile shape, subcloud equivalent potential temperature, subcloud lapse rates of temperature and moisture, and wind profile held fixed. For each CAPE, one final simulation is conducted using a near optimal LFC, but a lowered LCL, with a neutrally buoyant environmental thermal profile specified in between. Results show that, for the buoyancy-starved small-CAPE environments, the simulated storms are supercells and are generally largest and most intense when LCL=LFC altitudes lie in the approximate range 1.5-2.5 km above the surface. The simulations show similar trends for the shear-starved large-CAPE environments, except that conversion from supercell to multicell morphology frequently occurs when the LCL is high. For choices of LCL=LFC height within the optimal 1.5-2.5 km range, peak storm updraft overturning efficiency may approaches unity relative to parcel theory, while for lower LCL=LFC heights, overturning efficiency is reduced significantly. The enhancements of overturning efficiency and updraft diameter with increasing LFC height are shown to be the result of systematic increases in the mean equivalent potential temperature of the updraft at cloud base. For the shear

  10. Analysis of Summer Thunderstorms in Central Alabama Using the NASA Land Information System

    NASA Technical Reports Server (NTRS)

    James, Robert; Case, Jonathan; Molthan, Andrew; Jedloved, Gary

    2010-01-01

    Forecasters have difficulty predicting "random" afternoon thunderstorms during the summer months. Differences in soil characteristics could be a contributing factor for storms. The NASA Land Information System (LIS) may assist forecasters in predicting summer convection by identifying boundaries in land characteristics. This project identified case dates during the summer of 2009 by analyzing synoptic weather maps, radar, and satellite data to look for weak atmospheric forcing and disorganized convective development. Boundaries in land characteristics that may have lead to convective initiation in central Alabama were then identified using LIS.

  11. Fractal identification of supercell storms

    NASA Astrophysics Data System (ADS)

    Féral, Laurent; Sauvageot, Henri

    2002-07-01

    The most intense and violent form of convective storm is the supercell storm, usually associated with heavy rain, hail, and destructive gusty winds, downbursts, and tornadoes. Identifying a storm cell as a supercell storm is not easy. What is shown here, from radar data, is that when an ordinary, or multicell storm evolves towards the supercellular organization, its fractal dimension is modified. Whereas the fractal dimension of the ordinary convective storms, including multicell thunderstorms, is observed around 1.35, in agreement with previous results, the fractal dimension of supercell storms is found close to 1.07. This low value is due to the unicellular character of supercells. The present paper suggests that the fractal dimension is a parameter that should be considered to analyse the dynamical organization of a convective field and to detect and identify the supercell storms, either isolated or among a population of convective storms.

  12. Performance Evaluation of PBL Schemes of ARW Model in Simulating Thermo-Dynamical Structure of Pre-Monsoon Convective Episodes over Kharagpur Using STORM Data Sets

    NASA Astrophysics Data System (ADS)

    Madala, Srikanth; Satyanarayana, A. N. V.; Srinivas, C. V.; Tyagi, Bhishma

    2016-05-01

    In the present study, advanced research WRF (ARW) model is employed to simulate convective thunderstorm episodes over Kharagpur (22°30'N, 87°20'E) region of Gangetic West Bengal, India. High-resolution simulations are conducted using 1 × 1 degree NCEP final analysis meteorological fields for initial and boundary conditions for events. The performance of two non-local [Yonsei University (YSU), Asymmetric Convective Model version 2 (ACM2)] and two local turbulence kinetic energy closures [Mellor-Yamada-Janjic (MYJ), Bougeault-Lacarrere (BouLac)] are evaluated in simulating planetary boundary layer (PBL) parameters and thermodynamic structure of the atmosphere. The model-simulated parameters are validated with available in situ meteorological observations obtained from micro-meteorological tower as well has high-resolution DigiCORA radiosonde ascents during STORM-2007 field experiment at the study location and Doppler Weather Radar (DWR) imageries. It has been found that the PBL structure simulated with the TKE closures MYJ and BouLac are in better agreement with observations than the non-local closures. The model simulations with these schemes also captured the reflectivity, surface pressure patterns such as wake-low, meso-high, pre-squall low and the convective updrafts and downdrafts reasonably well. Qualitative and quantitative comparisons reveal that the MYJ followed by BouLac schemes better simulated various features of the thunderstorm events over Kharagpur region. The better performance of MYJ followed by BouLac is evident in the lesser mean bias, mean absolute error, root mean square error and good correlation coefficient for various surface meteorological variables as well as thermo-dynamical structure of the atmosphere relative to other PBL schemes. The better performance of the TKE closures may be attributed to their higher mixing efficiency, larger convective energy and better simulation of humidity promoting moist convection relative to non

  13. The characteristics of summer sub-hourly rainfall over the southern UK in a high-resolution convective permitting model

    NASA Astrophysics Data System (ADS)

    Chan, S. C.; Kendon, E. J.; Roberts, N. M.; Fowler, H. J.; Blenkinsop, S.

    2016-09-01

    Flash flooding is often caused by sub-hourly rainfall extremes. Here, we examine southern UK sub-hourly 10 min rainfall from Met Office state-of-the-art convective-permitting model simulations for the present and future climate. Observational studies have shown that the duration of rainfall can decrease with temperature in summer in some regions. The duration decrease coincides with an intensification of sub-hourly rainfall extremes. This suggests that rainfall duration and sub-hourly rainfall intensity may change in future under climate change with important implications for future changes in flash flooding risk. The simulations show clear intensification of sub-hourly rainfall, but we fail to detect any decrease in rainfall duration. In fact, model results suggest the opposite with a slight (probably insignificant) lengthening of both extreme and non-extreme rainfall events in the future. The lengthening is driven by rainfall intensification without clear changes in the shape of the event profile. Other metrics are also examined, including the relationship between intense 10 min rainfall and temperature, and return levels changes; all are consistent with results found for hourly rainfall. No evaluation of model performance at the sub-hourly timescale is possible, highlighting the need for high-quality sub-hourly observations. Such sub-hourly observations will advance our understanding of the future risks of flash flooding.

  14. North Equatorial Indian Ocean Convection and Indian Summer Monsoon June Progression: a Case Study of 2013 and 2014

    NASA Astrophysics Data System (ADS)

    Yadav, Ramesh Kumar; Singh, Bhupendra Bahadur

    2016-06-01

    The consecutive summer monsoons of 2013 and 2014 over the Indian subcontinent saw very contrasting onsets and progressions during the initial month. While the 2013 monsoon saw the timely onset and one of the fastest progressions during the recent decades, 2014 had a delayed onset and a slower progression phase. The monthly rainfall of June 2013 was +34 %, whereas in 2014 it was -43 % of its long-period average. The progress/onset of monsoon in June is influenced by large-scale circulation and local feedback processes. But, in 2013 (2014), one of the main reasons for the timely onset and fastest progression (delayed onset and slower progression) was the persistent strong (weak) convection over the north equatorial Indian Ocean during May. This resulted in a strong (weak) Hadley circulation with strong (weak) ascent and descent over the north equatorial Indian Ocean and the South Indian Ocean, respectively. The strong (weak) descent over the south Indian Ocean intensified (weakened) the Mascarene High, which in turn strengthened (weakened) the cross-equatorial flow and hence the monsoonal circulation.

  15. Effects of acid deposition on dissolution of carbonate stone during summer storms in the Adirondack Mountains, New York, 1987-89

    USGS Publications Warehouse

    Schuster, Paul F.; Reddy, Michael M.; Sherwood, S.I.

    1994-01-01

    This study is part of a long-term research program designed to identify and quantify acid rain damage to carbonate stone. Acidic deposition accelerates the dissolution of carbonate-stone monuments and building materials. Sequential sampling of runoff from carbonate-stone (marble) and glass (reference) microcatchments in the Adirondack Mountains in New York State provided a detailed record of the episodic fluctuations in rain rate and runoff chemistry during individual summer storms. Rain rate and chemical concentrations from carbonate-stone and glass runoff fluctuated three to tenfold during storms. Net calcium-ion concentrations from the carbonatestone runoff, a measure of stone dissolution, typically fluctuated twofold during these storms. High net sulfate and net calcium concentrations in the first effective runoff at the start of a storm indicated that atmospheric pollutants deposited on the stone surface during dry periods formed calcium sulfate minerals, an important process in carbonate stone dissolution. Dissolution of the carbonate stone generally increased up to twofold during coincident episodes of low rain rate (less than 5 millimeters per hour) and decreased rainfall (glass runoff) pH (less than 4.0); episodes of high rain rate (cloudbursts) were coincident with a rapid increase in rainfall pH and also a rapid decrease in the dissolution of carbonate-stone. During a storm, it seems the most important factors causing increased dissolution of carbonate stone are coincident periods of low rain rate and decreased rainfall pH. Dissolution of the carbonate stone decreased slightly as the rain rate exceeded about 5 millimeters per hour, probably in response to rapidly increasing rainfall pH during episodes of high rain rate and shorter contact time between the runoff and the stone surface. High runoff rates resulting from cloudbursts remove calcium sulfate minerals formed during dry periods prior to storms and also remove dissolution products formed in large

  16. Simulations of summer monsoon climate over East Asia with a Regional Climate Model (RegCM) using Tiedtke convective parameterization scheme (CPS)

    NASA Astrophysics Data System (ADS)

    Bao, Yan

    2013-12-01

    In this study, we implemented the Tiedtke convective parameterization scheme (CPS) into the Abdus Salam International Centre for Theoretical Physics (ICTP) Regional Climate Model version 3 (RegCM3) and simulated the East Asian Summer Monsoon (EASM) climate. A 6-year experiment was completed, from September 1996 through August 2002, and compared with an analogous experiment employing the Grell CPS option available in RegCM3. The ability of the model to represent the average climatology was investigated. Our results indicate that the Tiedtke CPS shows a generally good performance in describing surface climate and large-scale circulation throughout the summer monsoon period. Compared to the simulation with Grell CPS, the simulation with Tiedtke scheme shows a number of improvements, including a better distribution of summer monsoon precipitation due to a better positioning of the Western Pacific Subtropical High (WPSH) in the middle troposphere and the southwesterly jet in the lower troposphere, and more realistic seasonal evolution of the monsoon precipitation. The cold surface air temperature bias characteristic frequently seen in Grell scheme over this region is also reduced. Generally, the Tiedtke scheme simulates warm and wet atmospheric conditions in the middle and lower tropospheres, a result more in agreement with the European Centre for Medium-Range Weather Forecasts (ECMWF) 40 Years analysis (ERA-40). The Tiedtke scheme is more prone to activate convection in the lower troposphere than the Grell scheme due to more moist static energy available for activating and supporting the development of convection systems.

  17. Inter-comparison of deep convection over the Tibetan Plateau-Asian Monsoon Region and subtropical North America in boreal summer using CloudSat/CALIPSO data

    NASA Astrophysics Data System (ADS)

    Luo, Y.; Zhang, R.; Qian, W.; Luo, Z.

    2010-12-01

    Deep convection at the Tibetan Plateau-Southern Asian Monsoon Region (TP-SAMR) is analyzed using CloudSat and CALIPSO data for the boreal summer season (June-August) from 2006 to 2009. Three sub-regions - the Tibetan Plateau (TP), southern slope of the Plateau (PSS), and southern Asian monsoon region (SAMR) - are defined and deep convection properties are compared among these sub-regions. To cast them in a broader context, we also bring in four additional regions that bear some similarity to the TP-SAMR: East Asia (EA), tropical northwestern Pacific (NWP), west and east North America (WNA, ENA). The principal findings are as follows: 1) Compared to the other two sub-regions of the TP-SAMR, deep convection at the TP is shallower, less frequent, and embedded in smaller-size convection systems, but the cloud tops are more densely packed. These characteristics of deep convection at the TP are closely related to the significantly lower level of neutral buoyancy (LNB) and much drier atmosphere. 2) In a broader context where all seven regions are brought together, deep convection at the two tropical regions (NWP and SAMR; mostly over ocean) is similar in many regards. Similar conclusion can be drawn among the four subtropical continental regions (TP, EA, WNA, and ENA). However, tropical oceanic and subtropical land regions present some significant contrasts: deep convection in the latter region occurs less frequently, has lower cloud tops but comparable or slightly higher tops of large radar echo, and is embedded in smaller systems. The cloud tops of the subtropical land regions are generally more densely packed. Hence, the difference between TP and SAMR is more of a general contrast between subtropical land regions and tropical oceanic regions during the boreal summer. 3) Deep convection at the PSS possesses some uniqueness of its own because of the distinctive terrain (slopes) and moist low-level monsoon flow. 4) Results from comparison between the daytime and the

  18. Intercomparison of Deep Convection over the Tibetan Plateau-Asian Monsoon Region and Subtropical North America in Boreal Summer Using CloudSat/CALIPSO Data

    NASA Astrophysics Data System (ADS)

    Luo, Y.; Zhang, R.; Qian, W.; Luo, Z.

    2012-04-01

    Deep convection in the Tibetan Plateau-southern Asian monsoon region (TP-SAMR) is analyzed using CloudSat and Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) data for the boreal summer season (June-August) from 2006 to 2009. Three subregions are defined—the TP, the southern slope of the plateau (PSS), and the SAMR—and deep convection properties (such as occurrence frequency, internal vertical structure, system size, and local environment) are compared among these subregions. To cast them in a broader context, four additional regions that bear some similarity to the TP-SAMR are also discussed: East Asia (EA), tropical northwestern Pacific (NWP), and western and eastern North America (WNA and ENA, respectively). The principal findings are as follows: 1) Compared to the other two subregions of the TP-SAMR, deep convection over the TP is shallower, less frequent, and embedded in smaller-size convection systems, but the cloud tops are more densely packed. These characteristics of deep convection over the TP are closely related to the unique local environment, namely, a significantly lower level of neutral buoyancy (LNB) and much drier atmosphere. 2) In a broader context in which all seven regions are brought together, deep convection in the two tropical regions (NWP and SAMR; mostly over ocean) is similar in many regards. A similar conclusion can be drawn among the four subtropical continental regions (TP, EA, WNA, and ENA). However, tropical oceanic and subtropical land regions present some significant contrasts: deep convection in the latter region occurs less frequently, has lower cloud tops but comparable or slightly higher tops of large radar echo (e.g., 0 and 10 dBZ), and is embedded in smaller systems. The cloud tops of the subtropical land regions are generally more densely packed.Hence, the difference between the TP and SAMRismore of a general contrast between subtropical land regions and tropical oceanic regions during the

  19. Simulation of Indian summer monsoon onset with different parameterization convection schemes of RegCM-4.3

    NASA Astrophysics Data System (ADS)

    Bhatla, R.; Ghosh, S.; Mandal, B.; Mall, R. K.; Sharma, Kuldeep

    2016-07-01

    Simulation of Indian Summer Monsoon (ISM) onset over South Asia Coordinated Regional Climate Downscaling Experiment (CORDEX) domain in pentad composite pattern is considered for this study. The latest version of the International Center for Theoretical Physics' (ICTP's) Regional Climate Model version 4.3 (RegCM-4.3) is used for the simulation of a pentad composite onset for three time period: Pre-onset, Onset and Post-onset periods of ISM. Each pentad composite is average of five consecutive days. 10 years (2001-2010) worth of pentad composites of rainfall, mean sea level pressure (MSLP), outgoing longwave radiation (OLR), wind at 850 hPa and 925 hPa levels till 7 days prior to the date of onset of monsoon and 7 days after the onset are analyzed to find out the predictive skill. Six Parameterization convection schemes (PCSs) viz. Kuo, Mix98, Mix99, Tiedtke, Emanuel and Grell are used in sensitivity experiment and estimation of their performance has been done. From the experiment, some modulation is found in the OLR field (≤ 200 Wm- 2) within the region 5°N-10°N and 70°N-75°E. Yearly analysis has shown the strength of wind at 925 hPa over the region 5°N-10°N and 70°E-80°E on pentad composite onset of ISM. Yearly analysis is conducted for finding the best fitted PCS which has provided the precursor for simulating the onset.

  20. Magnetospheric Convection Electric Field Dynamics and Stormtime Particle Energization: Case Study of the Magnetic Storm of May 4,1998

    NASA Technical Reports Server (NTRS)

    Khazanov, George V.; Liemohn, Michael W.; Newman, Tim S.; Fok, Mei-Ching; Ridley, Aaron

    2003-01-01

    It is shown that narrow channels of high electric field are an effective mechanism for injecting plasma into the inner magnetosphere. Analytical expressions for the electric field cannot produce these channels of intense plasma flow, and thus result in less entry and energization of the plasma sheet into near-Earth space. For the ions, omission of these channels leads to an underprediction of the strength of the stormtime ring current and therefore an underestimation of the geoeffectiveness of the storm event. For the electrons, omission of these channels leads to the inability to create a seed population of 10-100 keV electrons deep in the inner magnetosphere. These electrons can eventually be accelerated into MeV radiation belt particles.

  1. The impact of revised simplified Arakawa-Schubert convection parameterization scheme in CFSv2 on the simulation of the Indian summer monsoon

    NASA Astrophysics Data System (ADS)

    Ganai, Malay; Mukhopadhyay, P.; Krishna, R. Phani Murali; Mahakur, M.

    2015-08-01

    Keeping the systematic bias of the climate forecast system model version 2 (CFSv2) in mind, an attempt is made to improve the Indian summer monsoon (ISM) rainfall variability in the model from diurnal through daily to seasonal scale. Experiments with default simplified Arakawa-Schubert (SAS) and a revised SAS schemes are carried out to make 15 years climate run (free run) to evaluate the model fidelity with revised SAS as compared to default SAS. It is clearly seen that the revised SAS is able to reduce some of the biases of CFSv2 with default SAS. Improvement is seen in the annual seasonal cycle, onset and withdrawal but most importantly the rainfall probability distribution function (PDF) has improved significantly. To understand the reason behind the PDF improvement, the diurnal rainfall simulation is analysed and it is found that the PDF of diurnal rainfall has significantly improved with respect to even a high resolution CFSv2 T382 version. In the diurnal run with revised SAS, the PDF of rainfall over central India has remarkably improved. The improvement of diurnal cycle of total rainfall has actually been contributed by the improvement of diurnal cycle of convection and associated convective rainfall. This is reflected in outgoing longwave radiation and high cloud diurnal cycle. This improvement of convective cycle has resolved a long standing problem of dry bias by CFSv2 over Indian land mass and wet bias over equatorial Indian Ocean. Besides the improvement, there are some areas where there are still scopes for further development. The cold tropospheric temperature bias, low cloud fractions need further improvement. To check the role of shallow convection, another free run is made with revised SAS along with shallow convection (SC). The major difference between the new and old SC schemes lies in the heating and cooling behavior in lower-atmospheric layers above the planetary boundary layer. However, the inclusion of revised SC scheme could not show much

  2. Response of mating activity of the plainfin midshipman to inflow into San Francisco Bay from a summer storm

    NASA Astrophysics Data System (ADS)

    Bland, R. W.

    2010-12-01

    The plainfin midshipman (Porichthys notatus) is a small fish which nests in estuarine waters during summer months. The male makes a loud continuous droning call to attract females to a nest, where eggs and newborn young are guarded by the male. Midshipman calls have been recorded continuously with a fixed hydrophone near a pier in San Francisco Bay, over two successive mating seasons. A dramatic increase in calling followed a very unusual intense rainstorm in mid-October 2009. This suggests a response to biochemical stimuli from the runoff water. Further study may make it possible to isolate the contaminants producing this alteration of sexual behavior.

  3. Vertical structure of cumulonimbus towers and intense convective clouds over the South Asian region during the summer monsoon season

    NASA Astrophysics Data System (ADS)

    Bhat, G. S.; Kumar, Shailendra

    2015-03-01

    The vertical structure of radar reflectivity factor in active convective clouds that form during the South Asian monsoon season is reported using the 2A25 version 6 data product derived from the precipitation radar measurements on board the Tropical Rainfall Measuring Mission satellite. We define two types of convective cells, namely, cumulonimbus towers (CbTs) and intense convective cells (ICCs). CbT is defined referring to a reflectivity threshold of 20 dBZ at 12 km altitude and is at least 9 km thick. ICCs are constructed referring to reflectivity thresholds at 8 km and 3 km altitudes. Cloud properties reported here are based on 10 year climatology. It is observed that the frequency of occurrence of CbTs is highest over the foothills of Himalayas, plains of northern India and Bangladesh, and minimum over the Arabian Sea and equatorial Indian Ocean west of 90°E. The regional differences depend on the reference height selected, namely, small in the case of CbTs and prominent in 6-13 km height range for ICCs. Land cells are more intense than the oceanic ones for convective cells defined using the reflectivity threshold at 3 km, whereas land versus ocean contrasts are not observed in the case of CbTs. Compared to cumulonimbus clouds elsewhere in the tropics, the South Asian counterparts have higher reflectivity values above 11 km altitude.

  4. Rocket dust storms and detached dust layers in the Martian atmosphere

    NASA Astrophysics Data System (ADS)

    Spiga, Aymeric; Faure, Julien; Madeleine, Jean-Baptiste; Määttänen, Anni; Forget, François

    2013-04-01

    Airborne dust is the main climatic agent in the Martian environment. Local dust storms play a key role in the dust cycle; yet their life cycle is poorly known. Here we use mesoscale modeling that includes the transport of radiatively active dust to predict the evolution of a local dust storm monitored by OMEGA on board Mars Express. We show that the evolution of this dust storm is governed by deep convective motions. The supply of convective energy is provided by the absorption of incoming sunlight by dust particles, rather than by latent heating as in moist convection on Earth. We propose to use the terminology "rocket dust storm," or conio-cumulonimbus, to describe those storms in which rapid and efficient vertical transport takes place, injecting dust particles at high altitudes in the Martian troposphere (30-50 km). Combined to horizontal transport by large-scale winds, rocket dust storms produce detached layers of dust reminiscent of those observed with Mars Global Surveyor and Mars Reconnaissance Orbiter. Since nighttime sedimentation is less efficient than daytime convective transport, and the detached dust layers can convect during the daytime, these layers can be stable for several days. The peak activity of rocket dust storms is expected in low-latitude regions at clear seasons (late northern winter to late northern summer), which accounts for the high-altitude tropical dust maxima unveiled by Mars Climate Sounder. Dust-driven deep convection has strong implications for the Martian dust cycle, thermal structure, atmospheric dynamics, cloud microphysics, chemistry, and robotic and human exploration.

  5. NASA's 3-D Animation of Tropical Storm Ulika from Space

    NASA Video Gallery

    An animated 3-D flyby of Tropical Storm Ulika using GPM's Radar data showed some strong convective storms inside the tropical storm were dropping precipitation at a rate of over 187 mm (7.4 inches)...

  6. Features of clouds and convection during the pre- and post-onset periods of the Asian summer monsoon

    NASA Astrophysics Data System (ADS)

    Wang, Yi; Wang, Chenghai

    2016-02-01

    The statistical characteristics of the vertical structure of clouds in the Asian summer monsoon region are investigated using two CloudSat standard products (Geometrical Profiling Product (GEOPROF) and GEOPROF-lidar) during the pre- and post-onset periods of the Asian summer monsoon, from April to August in 2007-2010. The characteristics of the vertical structure of clouds are analyzed and compared for different underlying surfaces in four subregions during this period. Also analyzed are the evolution of precipitation and hydrometeors with the northward advance of the Asian summer monsoon, and different hydrometeor characteristics attributed to the underlying surface features. The results indicate that the vertical cloud amounts increase significantly after the summer monsoon onset; this increase occurs first in the upper troposphere and then at lower altitudes over tropical regions (South Asian and tropical Northwest Pacific regions). The heights of the cloud top ascend, and the vertical height between the top and the base of the whole cloud increases. Single-layer (SL) and double-layer (DL) hydrometeors contribute over half and one third of the cloudiness in these 5 months (April to August), respectively. The multilayer frequencies increase in four different regions, and cloud layer depths (CLD) increase after the summer monsoon onset. These changes are stronger in tropical regions than in subtropical regions, while the vertical distance between cloud layers (VDCL) deceases in tropical regions and increases in subtropical regions.

  7. The Indian summer monsoon drought of 2002 and its linkage with tropical convective activity over northwest Pacific

    NASA Astrophysics Data System (ADS)

    Mujumdar, Milind; Kumar, Vinay; Krishnan, R.

    2007-06-01

    The Indian subcontinent witnessed a severe monsoon drought in 2002, which largely resulted from a major rainfall deficiency in the month of July. While moderate El Nino conditions prevailed during this period, the atmospheric convective activity was anomalously enhanced over northwest and north-central Pacific in the 10-20°N latitude belt; and heavy rainfall occurred over this region in association with a series of northward moving tropical cyclones. Similar out-of-phase rainfall variations over the Indian region and the northwest (NW) Pacific have been observed during other instances of El Nino/Southern Oscillation (ENSO). The dynamical linkage corresponding to this out-of-phase rainfall variability is explored in this study by conducting a set of numerical experiments using an atmospheric general circulation model. The results from the model simulations lend credence to the role of the tropical Pacific sea surface temperature anomalies in forcing the out-of-phase precipitation variability over the NW Pacific and the Indian monsoon region. It is seen that the ENSO induced circulation response reveals an anomalous pattern comprising of alternating highs and lows which extend meridionally from the equatorial region into the sub-tropic and mid-latitude regions of west-central Pacific. This meridional pattern is associated with an anomalous cyclonic circulation over NW Pacific, which is found to favor enhanced tropical cyclonic activity and intensified convection over the region. In turn, the intensified convection over NW Pacific induces subsidence and rainfall deficiency over the Indian landmass through anomalous east-west circulation in the 10-20°N latitude belt. Based on the present findings, it is suggested that the convective activity over NW Pacific is an important component in mediating the ENSO-monsoon teleconnection dynamics.

  8. Thyroid storm

    MedlinePlus

    Thyrotoxic storm; Hyperthyroid storm; Accelerated hyperthyroidism; Thyroid crisis; Thyrotoxicosis - thyroid storm ... Thyroid storm occurs due to a major stress such as trauma, heart attack , or infection. In rare cases, thyroid ...

  9. Calibration of a convective parameterization scheme in the WRF model and its impact on the simulation of East Asian summer monsoon precipitation

    DOE PAGES

    Yang, Ben; Zhang, Yaocun; Qian, Yun; Huang, Anning; Yan, Huiping

    2014-03-26

    Reasonably modeling the magnitude, south-north gradient and seasonal propagation of precipitation associated with the East Asian Summer Monsoon (EASM) is a challenging task in the climate community. In this study we calibrate five key parameters in the Kain-Fritsch convection scheme in the WRF model using an efficient importance-sampling algorithm to improve the EASM simulation. We also examine the impacts of the improved EASM precipitation on other physical process. Our results suggest similar model sensitivity and values of optimized parameters across years with different EASM intensities. By applying the optimal parameters, the simulated precipitation and surface energy features are generally improved.more » The parameters related to downdraft, entrainment coefficients and CAPE consumption time (CCT) can most sensitively affect the precipitation and atmospheric features. Larger downdraft coefficient or CCT decrease the heavy rainfall frequency, while larger entrainment coefficient delays the convection development but build up more potential for heavy rainfall events, causing a possible northward shift of rainfall distribution. The CCT is the most sensitive parameter over wet region and the downdraft parameter plays more important roles over drier northern region. Long-term simulations confirm that by using the optimized parameters the precipitation distributions are better simulated in both weak and strong EASM years. Due to more reasonable simulated precipitation condensational heating, the monsoon circulations are also improved. Lastly, by using the optimized parameters the biases in the retreating (beginning) of Mei-yu (northern China rainfall) simulated by the standard WRF model are evidently reduced and the seasonal and sub-seasonal variations of the monsoon precipitation are remarkably improved.« less

  10. Calibration of a convective parameterization scheme in the WRF model and its impact on the simulation of East Asian summer monsoon precipitation

    SciTech Connect

    Yang, Ben; Zhang, Yaocun; Qian, Yun; Huang, Anning; Yan, Huiping

    2014-03-26

    Reasonably modeling the magnitude, south-north gradient and seasonal propagation of precipitation associated with the East Asian Summer Monsoon (EASM) is a challenging task in the climate community. In this study we calibrate five key parameters in the Kain-Fritsch convection scheme in the WRF model using an efficient importance-sampling algorithm to improve the EASM simulation. We also examine the impacts of the improved EASM precipitation on other physical process. Our results suggest similar model sensitivity and values of optimized parameters across years with different EASM intensities. By applying the optimal parameters, the simulated precipitation and surface energy features are generally improved. The parameters related to downdraft, entrainment coefficients and CAPE consumption time (CCT) can most sensitively affect the precipitation and atmospheric features. Larger downdraft coefficient or CCT decrease the heavy rainfall frequency, while larger entrainment coefficient delays the convection development but build up more potential for heavy rainfall events, causing a possible northward shift of rainfall distribution. The CCT is the most sensitive parameter over wet region and the downdraft parameter plays more important roles over drier northern region. Long-term simulations confirm that by using the optimized parameters the precipitation distributions are better simulated in both weak and strong EASM years. Due to more reasonable simulated precipitation condensational heating, the monsoon circulations are also improved. Lastly, by using the optimized parameters the biases in the retreating (beginning) of Mei-yu (northern China rainfall) simulated by the standard WRF model are evidently reduced and the seasonal and sub-seasonal variations of the monsoon precipitation are remarkably improved.

  11. Numerical Study of OrograPhic-Convective Precipitation over the Eastern Arabian Sea and the Ghat Mountains during the Summer Monsoon.

    NASA Astrophysics Data System (ADS)

    Ogura, Yoshi; Yoshizaki, Masanori

    1988-08-01

    When the western coast of India lies in the path of the low-level west-southwest wind crossing the Arabian Sea during the summer monsoon season, deep convection frequently develops over the ocean off the coast. In such a situation, the maximum rainfall occurs near the coast, not over the Western Ghats. In order to study the physics underlying orographic-convective precipitation over this area, a two-dimensional compressible moist cloud model is applied. The model is written in terrain-following coordinates and includes the Coriolis force and a planetary boundary layer parameterization. The initial fields of thermodynamic variables are specified using observed data gathered upstream of the offshore precipitating systems over the Arabian Sea. Two wind profiles are considered: vertically uniform and nonuniform flows. The latter profile represents a monsoonal westerly jet at low levels and easterlies in the layer above 5 km. Three cases are considered for each wind profile by including or omitting moisture in the atmosphere and heat and moisture fluxes from the ocean.Among six cases considered, results from the moist and nonuniform wind profile case with heat and moisture fluxes from the ocean are found to be the most consistent with observations of precipitation rate, preferred location of rainfall, and lack of high-level clouds in the downwind side of the mountain. When fluxes from the ocean are excluded, the predicted rainfall accumulation is about the same. However, the maximum rainfall rate occurs over the mountain peak area, in disagreement with the observation. When fluxes from the ocean are included, but with the vertically uniform basic flow, the predicted maximum rainfall occurs at the coast. However, its rate is about half that observed. It is thus concluded that, in order to account for the observed features of rainfall over the Arabian Sea and the Ghat Mountains during the summer monsoon season, two factors, the strongly sheared environment and fluxes of

  12. Differences in Fine- Coarse Aerosol Ratios in Convective and Non-Convective Dust Events in a Desert City

    NASA Astrophysics Data System (ADS)

    Gill, T. E.; Rivera Rivera, N. I.; Novlan, D. J.

    2014-12-01

    El Paso, Texas (USA) and Ciudad Juarez, Chihuahua (Mexico) form the Paso del Norte, the largest metropolitan area in North America's Chihuahuan Desert. The cities are subject to frequent dust storms presenting a hazard to local infrastructure and health, including synoptic-scale dust events during winter and spring, and dusty outflows from convective storms (haboobs) primarily during the summer. We evaluate particulate matter (PM2.5 and PM10) concentrations over a decade of convective and non-convective dust events, based on hourly aerosol data collected by Texas Commission on Environmental Quality (TCEQ) continuous air monitors in El Paso cross-referenced to weather observations from the USA National Weather Service. A total of 219 dust events (95 convective and 124 non-convective) events occurred between 2001 and 2010. The PM2.5/PM10 ratio was significantly higher (proportionally greater concentration of fine aerosols) in convective episodes and during summertime events than during non-convective dust events and dust episodes in other seasons, although overall concentrations of both PM2.5 and PM10 were higher in the non-convective events, which were also longer-lasting. These differences in fine/coarse aerosol ratios are likely related to different atmospheric stability conditions, and/or different mechanisms of dust particle entrainment and transport in haboobs versus non-convective dust events. Since visibility degradation and adverse human health effects are known to be exacerbated by to fine aerosol concentrations, thunderstorm-related dust events may present a proportionally greater hazard.

  13. North Polar Dust Storm

    NASA Technical Reports Server (NTRS)

    2003-01-01

    MGS MOC Release No. MOC2-334, 18 April 2003

    This composite of Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) wide angle daily global images shows a north polar dust storm on March 7, 2003. Similar late summer storms occurred nearly every day from late February well into April 2003; these were also seen in late summer in 1999 and 2001. The white features at the top of the image are the water ice surfaces of the north polar residual cap. Sunlight illuminates the scene from the lower left.

  14. The Role of Convection in Redistributing Formaldehyde to the Upper Troposphere Over North America and the North Atlantic during the Summer 2004 INTEX Campaign

    NASA Technical Reports Server (NTRS)

    Fried, Alan; Olson, Jennifer R.; Walega, Jim; Crawford, Jim H.; Chen, Gao; Weibring, Petter; Richter, Dirk; Roller, Chad; Tittel, Frank; Porter, Michael; Fuelberg, Henry; Halland, Jeremy; Bertram, Timothy H.; Cohen, Ronald C.; Pickering, Kenneth; Heikes, Brian G.

    2007-01-01

    Measurements of CH2O from a tunable diode laser absorption spectrometer (TDLAS) were acquired onboard the NASA DC-8 during the summer 2004 INTEX-NA (Intercontinental Chemical Transport Experiment - North America) campaign to test our understanding of convection and production mechanisms in the upper troposphere (UT, 6-12-km) over continental North America and the North Atlantic Ocean. Point-by-point comparisons with box model calculations, when MHP (CH3OOH) measurements were available for model constraint, resulted in a median CH2O measurement/model ratio of 0.91 in the UT. Multiple tracers were used to arrive at a set of UT CH2O background and perturbed air mass periods, and 46% of the TDLAS measurements fell within the latter category. At least 66% to 73% of these elevated UT observations were caused by enhanced production from CH2O precursors rather than direct transport of CH2O from the boundary layer. This distinction is important, since the effects from the former can last for over a week or more compared to one day or less in the case of convective transport of CH2O itself. In general, production of CH2O from CH4 was found to be the dominant source term, even in perturbed air masses. This was followed by production from MHP, methanol, PAN type compounds, and ketones, in descending order of their contribution. In the presence of elevated NO from lightning and potentially from the stratosphere, there was a definite trend in the CH2O discrepancy, which for the highest NO mixing ratios produced a median CH2O measurement/model ratio of 3.9 in the 10-12-km range. Discrepancies in CH2O and HO2 in the UT with NO were highly correlated and this provided further information as to the possible mechanism(s) responsible. These discrepancies with NO are consistent with additional production sources of both gases involving CH3O2 + NO reactions, most likely caused by unmeasured hydrocarbons.

  15. Variability of the TRMM-PR total and convective and stratiform rain fractions over the Indian region during the summer monsoon

    NASA Astrophysics Data System (ADS)

    Pokhrel, Samir; Sikka, D. R.

    2013-07-01

    Level 3 (3A25) TRMM Precipitation Radar (PR) data are used for 13 years period (1998-2010) to prepare climatology of TRMM PR derived near surface rain (Total rain) and rain fractions for the 4-months duration of Indian Summer Monsoon season (June-September) as well as for individual months. It is found that the total rain is contributed mostly (99 %) by two rain fractions i.e. stratiform and convective rain fractions for the season as well as on the monthly basis. It is also found that total rain estimates by PR are about 65 % of the gauge measured rain over continental India as well as on sub-regional basis. Inter-annual variability of TRMM-PR rain estimates for India mainland and its sub-regions as well as over the neighboring oceanic regions, in terms of coefficient of variability (CV) is discussed. The heaviest rain region over north Bay of Bengal (BoB) is found to have the lowest CV. Another sub-region of low CV lies over the eastern equatorial Indian ocean (EEIO). The CVs of total rain as well as its two major constituents are found to be higher on monthly basis compared to seasonal basis. Existence of a well known dipole between the EEIO and the north BoB is well recognized in PR data also. Significant variation in PR rainfall is found over continental India between excess and deficit monsoon seasons as well as between excess and deficit rainfall months of July and August. Examination of rainfall fractions between the BoB and Central India on year to year basis shows that compensation in rainfall fractions exists on monthly scale on both the regions. Also on the seasonal and monthly scales, compensation is observed in extreme monsoon seasons between the two regions. However, much less compensation is observed between the north BoB and EEIO belts in extreme rain months. This leads to speculation that the deficit and excess seasons over India may result from slight shift of the rainfall from Central India to the neighboring oceanic regions of north Bo

  16. High-Resolution Modeling of the Predictability of Convective Systems, and Influences by Absorbing Aerosols Over Northern India and the Himalayas Foothills During Boreal Summer

    NASA Technical Reports Server (NTRS)

    Kim, Kyu-Myong; Lau, William K.-M.; Tao, Wei-Kuo; Shi, Jainn; Tan, Qian; Chin, Mian; Matsui, Toshihisa; Bian, Huisheng

    2011-01-01

    The Himalayas foothills region (HFR) is an important component of the South Asian monsoon. To the south, the HFR borders the fertile, populous, and heavily polluted Indo-Gangetic Plain (IGP). To the north, it rises to great height (approx. 4-5 km) to the Tibetan Plateau over a distance of less than 100 km. The HFR itself consists of complex mountainous terrain, with strong orographic forcing for precipitation. During the late spring and early summer, dust aerosol from the Thar and Middle East deserts , as well as moisture from the Arabian Sea were transported to the western part of the western part of the IGP and foothills spurs pre-monsoon severe thunderstorm over the region. During the monsoon season (mid June -August) convection from the Bay of Bengal, spread along the foothills northwestward to northern Pakistan. Recent climate model studies and preliminary observations have indicted not only the importance of dynamical forcing of precipitation in the HFR, but also possible strong impacts by the dense aerosols, from both local sources, and remote transport, that blanket the IGP from late spring up to the onset of the monsoon in June, and during monsoon breaks in July. In this work, we use the NASA Unified Weather Research and Forecasting (Nu-WRF) model to study the predictability ( 1-7 days) South Asian monsoon rainfall system. Results of 7 -day forecast experiments using an embedded domain of 27 km and 9 km resolution were conducted for the period June 11- July 15, 2008, with and without aerosol forcing are carried out to assess the intrinsic predictability of rainfall over the HFR, and possible impacts by aerosol direct effect, and possible connection of large-scale South Asian monsoon system.

  17. Climatology of summer midtropospheric perturbations in the U.S. northern plains. Part I: Influence on northwest flow severe weather outbreaks

    SciTech Connect

    Wang, Shih-Yu; Chen, Tsing-Chang; Correia, James

    2011-02-13

    Northwest flow severe weather outbreaks (NWF outbreaks) describe a type of summer convective storm that occurs in areas of mid-level NWF in the central United States. Convective storms associated with NWF outbreaks are often progressive (i.e. traveling a long distance) along systematic, northwestsoutheast oriented tracks throughout the northern plains. Previous studies have observed that progressive convective storms under NWF are often coupled with subsynoptic-scale midtropospheric perturbations (MPs) coming from the Rocky Mountains. This study traces such MPs for the decade of 1997-2006 using the North American Regional Reanalysis to examine their climatology and possible influence on NWF outbreaks. MPs initiated over the Rocky Mountains have a maximum frequency in July when the North American anticyclone fully develops and forms prevailing NWF over the northern plains. MPs developed under this anticyclone appear restricted in their vertical extension. Nevertheless, persistent upward motion is apparent in the leading edge (east) of MPs soon after their genesis subsequently inducing or intensifying convective storms. MPs propagate along systematic tracks similar to those of NWF outbreaks. The propagation of MPs also synchronizes with the progressive behavior of the associated convective storms. When encountering strong low-level jets (LLJs), upward motion and convergence of water vapor flux associated with MPs intensify substantially, resulting in strongly enhanced convection and precipitation. Convective wind and hail frequencies associated with MPs in strong LLJs reveal a pattern and magnitude very similar to that of NWF outbreaks. While about 60% of summer rainfall in the northern plains is linked to MPs, 75% of these instances occur in strong LLJs.

  18. Storm-Substorm Relations Workshop

    NASA Astrophysics Data System (ADS)

    Kan, Joe

    2006-06-01

    Magnetic storms in the magnetosphere can cause damage to communication satellites and large-scale power outages. The concept that a magnetic storm is a compilation of a series of substorms was proposed by Akasofu [1968]. However, Kamide [1992] showed that substorms are not a necessary condition for the occurrence of a magnetic storm. This controversy initiated a new era of research on the storm-substorm relation, which was the subject of a recent workshop in Banff, Alberta, Canada. The main topics discussed during the meeting included a brief overview of what a substorm is, how quasiperiodic substorm events and steady magnetospheric convection (SMC) events without substorms contribute to storms, and how plasma flows enhanced by magnetic reconnection in the plasma sheet contribute to substorms and storms.

  19. Development of lidar sensor for cloud-based measurements during convective conditions

    NASA Astrophysics Data System (ADS)

    Vishnu, R.; Bhavani Kumar, Y.; Rao, T. Narayana; Nair, Anish Kumar M.; Jayaraman, A.

    2016-05-01

    Atmospheric convection is a natural phenomena associated with heat transport. Convection is strong during daylight periods and rigorous in summer months. Severe ground heating associated with strong winds experienced during these periods. Tropics are considered as the source regions for strong convection. Formation of thunder storm clouds is common during this period. Location of cloud base and its associated dynamics is important to understand the influence of convection on the atmosphere. Lidars are sensitive to Mie scattering and are the suitable instruments for locating clouds in the atmosphere than instruments utilizing the radio frequency spectrum. Thunder storm clouds are composed of hydrometers and strongly scatter the laser light. Recently, a lidar technique was developed at National Atmospheric Research Laboratory (NARL), a Department of Space (DOS) unit, located at Gadanki near Tirupati. The lidar technique employs slant path operation and provides high resolution measurements on cloud base location in real-time. The laser based remote sensing technique allows measurement of atmosphere for every second at 7.5 m range resolution. The high resolution data permits assessment of updrafts at the cloud base. The lidar also provides real-time convective boundary layer height using aerosols as the tracers of atmospheric dynamics. The developed lidar sensor is planned for up-gradation with scanning facility to understand the cloud dynamics in the spatial direction. In this presentation, we present the lidar sensor technology and utilization of its technology for high resolution cloud base measurements during convective conditions over lidar site, Gadanki.

  20. Modeling haboob dust storms in large-scale weather and climate models

    NASA Astrophysics Data System (ADS)

    Pantillon, Florian; Knippertz, Peter; Marsham, John H.; Panitz, Hans-Jürgen; Bischoff-Gauss, Ingeborg

    2016-03-01

    Recent field campaigns have shown that haboob dust storms, formed by convective cold pool outflows, contribute a significant fraction of dust uplift over the Sahara and Sahel in summer. However, in situ observations are sparse and haboobs are frequently concealed by clouds in satellite imagery. Furthermore, most large-scale weather and climate models lack haboobs, because they do not explicitly represent convection. Here a 1 year long model run with explicit representation of convection delivers the first full seasonal cycle of haboobs over northern Africa. Using conservative estimates, the model suggests that haboobs contribute one fifth of the annual dust-generating winds over northern Africa, one fourth between May and October, and one third over the western Sahel during this season. A simple parameterization of haboobs has recently been developed for models with parameterized convection, based on the downdraft mass flux of convection schemes. It is applied here to two model runs with different horizontal resolutions and assessed against the explicit run. The parameterization succeeds in capturing the geographical distribution of haboobs and their seasonal cycle over the Sahara and Sahel. It can be tuned to the different horizontal resolutions, and different formulations are discussed with respect to the frequency of extreme events. The results show that the parameterization is reliable and may solve a major and long-standing issue in simulating dust storms in large-scale weather and climate models.

  1. Gravity wave initiated convection

    NASA Technical Reports Server (NTRS)

    Hung, R. J.

    1990-01-01

    The vertical velocity of convection initiated by gravity waves was investigated. In one particular case, the convective motion-initiated and supported by the gravity wave-induced activity (excluding contributions made by other mechanisms) reached its maximum value about one hour before the production of the funnel clouds. In another case, both rawinsonde and geosynchronous satellite imagery were used to study the life cycles of severe convective storms. Cloud modelling with input sounding data and rapid-scan imagery from GOES were used to investigate storm cloud formation, development and dissipation in terms of growth and collapse of cloud tops, as well as, the life cycles of the penetration of overshooting turrets above the tropopause. The results based on these two approaches are presented and discussed.

  2. Dust Storm

    Atmospheric Science Data Center

    2013-04-16

    article title:  Massive Dust Storm over Australia     View ... at JPL September 22, 2009 - Massive dust storm over Australia. project:  MISR category:  ... Sep 22, 2009 Images:  Dust Storm location:  Australia and New Zealand ...

  3. Observations of storm-induced mixing and Gulf Stream Ring incursion over the southern flank of Georges Bank: Winter and summer 1997

    NASA Astrophysics Data System (ADS)

    Lee, Craig M.; Brink, Kenneth H.

    2010-08-01

    High-resolution hydrographic measurements collected along the southern edge of Georges Bank during March and June-July 1997 focused on characterizing processes that drive fluxes of material between the slope and bank. Wintertime sampling characterized changes driven by a strong storm. A Scotian Shelf crossover event produced a ribbon of anomalously fresh water along the bank's southern flank that was diluted during the storm. Comparison of prestorm and poststorm sections shows that over the bank changes in heat and salt inventories are consistent with those expected solely from local surface fluxes. In deeper waters, advective effects, likely associated with frontal motion and eddies, are clearly important. Summertime surveys resolve the development of a massive intrusion of Gulf Stream-like waters onto the bank. East of the intrusion, a thin extrusion of bank water is drawn outward by the developing ring, exporting fresher water at a rate of about 7 × 104 m3/s. A large-amplitude Gulf Stream meander appears to initiate the extrusion, but it quickly evolves, near the bank edge, into a warm core ring. Ring water intrudes to approximately the 80 m isobath, 40 km inshore from the bank edge. The intrusion process seems analogous to the development of Gulf Stream shingles (a hydrodynamic instability) in the South Atlantic Bight. It appears that, once the intruded water is established on the bank, it remains there and dissipates in place. Although the intrusion is an extremely dramatic event, it is probably not actually a major contributor to shelf edge exchanges over a seasonal time scale.

  4. Polarimetric and Multi-Doppler Radar Observations of Sprite-producing Storms

    NASA Technical Reports Server (NTRS)

    Lang, TImothy J.; Lyons, Walter A.; Rutledge, Steven A.; Dolan, Brenda; Cummer, Steven A.; Krehbiel, Paul; Rison, William

    2014-01-01

    Sprites are caused by luminous electrical breakdown of the upper atmosphere, and frequently occur over large mesoscale precipitation systems. Two sprite-producing storms (on 8 and 25 June) were observed in Colorado during the summer of 2012. Unlike most past studies of sprites, these storms were observed by a polarimetric radar - the CSU-CHILL facility - which provided both PPI and RHI scans of the cases. Also available were multiple-Doppler syntheses from CSU-CHILL, local NEXRAD radars, and the CSU-Pawnee radar; as well as data from the Colorado Lightning Mapping Array (COLMA), high speed cameras, and other lightning-detection instrumentation. This unique dataset provided an unprecedented look at the detailed kinematic and microphysical structures of the thunderstorms as they produced sprites, including electrical alignment signatures in the immediate location of the charge layers neutralized by sprite-parent positive cloud-to-ground lightning strokes. One of the sprite-producing cases (25 June) featured an anomalous charge structure and may serve as a model for how sprites can be produced over convection rather than the more typical stratiform regions. Also to be presented will be evidence for advection of charge into a common stratiform precipitation region (on 8 June), which was then tapped by lightning originating from multiple different convective cores to produce sprites. Depending on the outcome of the 2013 convective season, polarimetric data from additional storms that produce sprites and other transient luminous events (TLEs) may be presented.

  5. Explosive supercell growth - A possible indicator for tropical storm intensification?

    NASA Technical Reports Server (NTRS)

    Venne, Monique G.; Lyons, Walter A.; Keen, Cecil S.; Black, Peter G.; Gentry, R. Cecil

    1989-01-01

    Several tropical storm observations are discussed which support the hypothesis that bursts of cloud-to-ground lightning near the center of a developing tropical storm (also called convective exhaust clouds and supercells), indicative of organized deep convection, could provide a valuable diagnostic for intensification over the next 12-36 hours. It is emphasized that further research is required in order to establish the exact role of supercells in tropical storm intensification.

  6. Characterizing the Relationships Among Lightning and Storm Parameters: Lightning as a Proxy Variable

    NASA Technical Reports Server (NTRS)

    Goodman, S. J.; Raghavan, R.; William, E.; Weber, M.; Boldi, B.; Matlin, A.; Wolfson, M.; Hodanish, S.; Sharp. D.

    1997-01-01

    We have gained important insights from prior studies that have suggested relationships between lightning and storm growth, decay, convective rain flux, vertical distribution of storm mass and echo volume in the region, and storm energetics. A study was initiated in the Summer of 1996 to determine how total (in-cloud plus ground) lightning observations might provide added knowledge to the forecaster in the determination and identification of severe thunderstorms and weather hazards in real-time. The Melbourne Weather Office was selected as a primary site to conduct this study because Melbourne is the only site in the world with continuous and open access to total lightning (LDAR) data and a Doppler (WSR-88D) radar. A Lightning Imaging Sensor Data Applications Demonstration (LISDAD) system was integrated into the forecaster's workstation during the Summer 1996 to allow the forecaster to interact in real-time with the multi-sensor data being displayed. LISDAD currently ingests LDAR data, the cloud-to-ground National Lightning Detection Network (NLDN) data, and the Melbourne radar data in f real-time. The interactive features provide the duty forecaster the ability to perform quick diagnostics on storm cells of interest. Upon selection of a storm cell, a pop-up box appears displaying the time-history of various storm parameters (e.g., maximum radar reflectivity, height of maximum reflectivity, echo-top height, NLDN and LDAR lightning flash rates, storm-based vertically integrated liquid water content). This product is archived to aid on detailed post-analysis.

  7. Dust Storm

    Atmospheric Science Data Center

    2013-04-16

    ... April 11, 2004 (top panels) contrast strongly with the dust storm that swept across Iraq and Saudi Arabia on May 13, 2004 (bottom panels). ... Apr 11 and May 13, 2004 Images:  Dust Storm location:  Middle East thumbnail:  ...

  8. Interaction Between Two Distinct Mesoscale Circulations During Summer in the Coastal Region of Eastern USA

    NASA Astrophysics Data System (ADS)

    Sims, Aaron P.; Raman, Sethu

    2016-07-01

    The interaction of two phenomena, a sea-breeze front and a thermally-driven local circulation, is investigated during the summer season. The sea-breeze circulation in the coastal Carolinas (USA) can be quite strong and the sea-breeze front often propagates well inland. The Sandhills, an area of sandy soils, is oriented roughly parallel to the coast and is located approximately 180 km inland. Differential heating is a strong driving force for convective development in this coastal region and the Sandhills front develops from the thermally-driven circulation caused by the differential heating of differing soil types. The sea-breeze and the Sandhills circulations have been previously studied independently, however, the interaction of these two phenomena is not well known. A combination of remote sensing, in situ observations, and numerical simulations is used to examine the interaction of these two fronts with remote sensing and in situ observations revealing the differential heating that occurs along the Sandhills region. Radar reflectivity is used to identify the two frontal features that converge and result in enhanced convection. A modelling simulation reveals the vertical structure of the frontal features, their propagation, and interaction, highlighting the interaction of the two fronts that results in enhanced convection between the Sandhills and the coast. Over the Sandhills region, differential heating triggers convective storms. Radar reflectivity and numerical simulation indicate the outflows from these convective storms to produce a shallow Sandhills front that in turn propagates toward the coast. As the two opposing fronts, the Sandhills front and the sea-breeze front, converge and interact, intense convection occurs resulting in additional storms.

  9. Regional scale flood modeling using NEXRAD rainfall, GIS, and HEC-HMS/RAS: a case study for the San Antonio River Basin Summer 2002 storm event.

    PubMed

    Knebl, M R; Yang, Z-L; Hutchison, K; Maidment, D R

    2005-06-01

    This paper develops a framework for regional scale flood modeling that integrates NEXRAD Level III rainfall, GIS, and a hydrological model (HEC-HMS/RAS). The San Antonio River Basin (about 4000 square miles, 10,000 km2) in Central Texas, USA, is the domain of the study because it is a region subject to frequent occurrences of severe flash flooding. A major flood in the summer of 2002 is chosen as a case to examine the modeling framework. The model consists of a rainfall-runoff model (HEC-HMS) that converts precipitation excess to overland flow and channel runoff, as well as a hydraulic model (HEC-RAS) that models unsteady state flow through the river channel network based on the HEC-HMS-derived hydrographs. HEC-HMS is run on a 4 x 4 km grid in the domain, a resolution consistent with the resolution of NEXRAD rainfall taken from the local river authority. Watershed parameters are calibrated manually to produce a good simulation of discharge at 12 subbasins. With the calibrated discharge, HEC-RAS is capable of producing floodplain polygons that are comparable to the satellite imagery. The modeling framework presented in this study incorporates a portion of the recently developed GIS tool named Map to Map that has been created on a local scale and extends it to a regional scale. The results of this research will benefit future modeling efforts by providing a tool for hydrological forecasts of flooding on a regional scale. While designed for the San Antonio River Basin, this regional scale model may be used as a prototype for model applications in other areas of the country.

  10. NASA's GPM Gets a Look at Newborn, Late Season Eastern Pacific Tropical Storm Sandra

    NASA Video Gallery

    On Nov. 24, GPM saw intense convective storms south of the tropical storm's center of circulation were dropping rain at a rate of over 80 mm (3.1 inches) per hour. Cloud tops reached heights above ...

  11. Characteristics of the seasonal variation of the surface total heating over the Tibetan Plateau and its surrounding area in summer 1998 and its relationship with the convection over the subtropical area of the western Pacific

    NASA Astrophysics Data System (ADS)

    Li, Wei; Chen, Longxun

    2003-05-01

    Using the dataset of 1998 TIPEX, the data of 6 automatic heat balance observational stations (AWS) from May to August 1998, a dataset of 52 surface observational stations over the Tibetan Plateau (TP) and its adjacent region, the daily rainfall amounts from about 300 stations in China, the outgoing longwave radiation (OLR) data received by the National Satellite Meteorological Center(NSMC) of China, and TBB data from GMS remote sensing of Japan, the characteristics of the seasonal variation of the surface total heating over TP and its surrounding area in summer 1998 and its relationship with the convection over the subtropical area of the western Pacific is studied in this paper. The results show that the surface total heating over TP had a close relationship with the onset of the rainy season, and after the onset of the rainy season, the regional mean surface total heating over TP decreased distinctly. Furthermore, the regional mean surface total heating over TP had very good negative correlation with TBB over the subtropical area of the western Pacific along 20 30°N, which shows that the surface total heating over TP was able to affect the convection over the subtropical area of the western Pacific.

  12. Magnetic Storms

    NASA Technical Reports Server (NTRS)

    Tsurutani, Bruce T.; Gonzalez, Walter D.

    1998-01-01

    One of the oldest mysteries in geomagnetism is the linkage between solar and geomagnetic activity. The 11-year cycles of both the numbers of sunspots and Earth geomagnetic storms were first noted by Sabine. A few years later, speculation on a causal relationship between flares and storms arose when Carrington reported that a large magnetic storm followed the great September 1859 solar flare. However, it was not until this century that a well-accepted statistical survey on large solar flares and geomagnetic storms was performed, and a significant correlation between flares and geomagnetic storms was noted. Although the two phenomena, one on the Sun and the other on the Earth, were statistically correlated, the exact physical linkage was still an unknown at this time. Various hypotheses were proposed, but it was not until interplanetary spacecraft measurements were available that a high-speed plasma stream rich in helium was associated with an intense solar flare. The velocity of the solar wind increased just prior to and during the helium passage, identifying the solar ejecta for the first time. Space plasma measurements and Skylab's coronagraph images of coronal mass elections (CMES) from the Sun firmly established the plasma link between the Sun and the Earth. One phenomenon associated with magnetic storms is brilliant "blood" red auroras, as shown.

  13. Weak linkage between the heaviest rainfall and tallest storms

    PubMed Central

    Hamada, Atsushi; Takayabu, Yukari N.; Liu, Chuntao; Zipser, Edward J.

    2015-01-01

    Conventionally, the heaviest rainfall has been linked to the tallest, most intense convective storms. However, the global picture of the linkage between extreme rainfall and convection remains unclear. Here we analyse an 11-year record of spaceborne precipitation radar observations and establish that a relatively small fraction of extreme convective events produces extreme rainfall rates in any region of the tropics and subtropics. Robust differences between extreme rainfall and convective events are found in the rainfall characteristics and environmental conditions, irrespective of region; most extreme rainfall events are characterized by less intense convection with intense radar echoes not extending to extremely high altitudes. Rainfall characteristics and environmental conditions both indicate the importance of warm-rain processes in producing extreme rainfall rates. Our results demonstrate that, even in regions where severe convective storms are representative extreme weather events, the heaviest rainfall events are mostly associated with less intense convection. PMID:25708295

  14. Tropical Storm Erin

    NASA Technical Reports Server (NTRS)

    2007-01-01

    Location: The Atlantic Ocean 210 miles south of Galveston, Texas Categorization: Tropical Storm Sustained Winds: 40 mph (60 km/hr)

    [figure removed for brevity, see original site] [figure removed for brevity, see original site] Infrared ImageMicrowave Image

    Infrared Images Because infrared radiation does not penetrate through clouds, AIRS infrared images show either the temperature of the cloud tops or the surface of the Earth in cloud-free regions. The lowest temperatures (in purple) are associated with high, cold cloud tops that make up the top of the storm. In cloud-free areas the AIRS instrument will receive the infrared radiation from the surface of the Earth, resulting in the warmest temperatures (orange/red).

    Microwave Images In the AIRS microwave imagery, deep blue areas in storms show where the most precipitation occurs, or where ice crystals are present in the convective cloud tops. Outside of these storm regions, deep blue areas may also occur over the sea surface due to its low radiation emissivity. On the other hand, land appears much warmer due to its high radiation emissivity.

    Microwave radiation from Earth's surface and lower atmosphere penetrates most clouds to a greater or lesser extent depending upon their water vapor, liquid water and ice content. Precipitation, and ice crystals found at the cloud tops where strong convection is taking place, act as barriers to microwave radiation. Because of this barrier effect, the AIRS microwave sensor detects only the radiation arising at or above their location in the atmospheric column. Where these barriers are not present, the microwave sensor detects radiation arising throughout the air column and down to the surface. Liquid surfaces (oceans, lakes and rivers) have 'low emissivity' (the signal isn't as strong) and their radiation brightness temperature is therefore low. Thus the ocean also appears 'low temperature' in the AIRS microwave images and is assigned the color blue

  15. Comparing and Linking Post-fire Hillslope Erosion and Channel Change for Different Storm Types

    NASA Astrophysics Data System (ADS)

    MacDonald, Lee; Kampf, Stephanie; Brogan, Dan; Schmeer, Sarah; Nelson, Peter

    2016-04-01

    Moderate and high severity wildfires can greatly reduce infiltration rates, leading to orders of magnitude increases in hillslope-scale runoff and erosion rates. These increases can cause dramatic downstream channel change, with post-fire deposition being most common, but this depends on the number, magnitude and timing of storm events. The objective of this study is to compare post-fire hillslope erosion rates and downstream channel change from two distinct rainfall events approximately one year after burning. The first was a set of relatively typical, higher-intensity convective storms in June-August 2013, and the second was a highly unusual, week-long ~270 mm rainstorm in September 2013. The study was conducted in two ~15 km2 watersheds that had two-thirds of their area burned at high or moderate severity by 2012 High Park Fire in northcentral Colorado, USA. Hillslope erosion was measured with sediment fences at 29 sites grouped into five clusters, with each cluster having an associated tipping bucket rain gage. Downstream channel change was monitored at approximately ten cross-sections in each of the two watersheds, Skin Gulch and Hill Gulch. Twelve summer storms produced an overall mean hillslope erosion of 6 Mg ha-1, with higher rainfall intensities at lower elevations and in Skin Gulch causing higher sediment yields. The higher sediment yields in Skin Gulch caused substantial downstream deposition of up to 0.8 m at most cross-sections. Generally lower rainfall in Hill Gulch resulted in less Horton overland flow and hence lower erosion rates and much less downstream deposition. The September storm had roughly twice as much rainfall as the summer thunderstorms, but there were much lower peak rainfall intensities and hillslope-scale sediment yields except where shallow bedrock induced saturation overland flow. The much longer duration of the September storm resulted in sustained high flows, and these flows plus the lower hillslope erosion caused most of the

  16. Daytime identification of summer hailstorm cells from MSG data

    NASA Astrophysics Data System (ADS)

    Merino, A.; López, L.; Sánchez, J. L.; García-Ortega, E.; Cattani, E.; Levizzani, V.

    2014-04-01

    Identifying deep convection is of paramount importance, as it may be associated with extreme weather phenomena that have significant impact on the environment, property and populations. A new method, the hail detection tool (HDT), is described for identifying hail-bearing storms using multispectral Meteosat Second Generation (MSG) data. HDT was conceived as a two-phase method, in which the first step is the convective mask (CM) algorithm devised for detection of deep convection, and the second a hail mask algorithm (HM) for the identification of hail-bearing clouds among cumulonimbus systems detected by CM. Both CM and HM are based on logistic regression models trained with multispectral MSG data sets comprised of summer convective events in the middle Ebro Valley (Spain) between 2006 and 2010, and detected by the RGB (red-green-blue) visualization technique (CM) or C-band weather radar system of the University of León. By means of the logistic regression approach, the probability of identifying a cumulonimbus event with CM or a hail event with HM are computed by exploiting a proper selection of MSG wavelengths or their combination. A number of cloud physical properties (liquid water path, optical thickness and effective cloud drop radius) were used to physically interpret results of statistical models from a meteorological perspective, using a method based on these "ingredients". Finally, the HDT was applied to a new validation sample consisting of events during summer 2011. The overall probability of detection was 76.9 % and the false alarm ratio 16.7 %.

  17. Influence of open water bodies on the generation of summertime convection over the Canadian Prairies

    NASA Astrophysics Data System (ADS)

    Joshi, D.; Bélair, S.; Carrera, M. L.; Leroyer, S.

    2014-12-01

    There are still numerous water features on the Canadian landscape that are not monitored. Specifically, there are landscape features (e.g. the prairies and Canadian shield regions of North America) that are ephemeral in nature and have a significant influence on convective storm generation and local weather patterns through turbulent exchanges of sensible and latent heat between land and the atmosphere. In this study we perform a series of numerical experiments with the GEM (Global Environmental Multiscale model) model at 2.5 km resolution to examine the sensitivity of the atmospheric boundary layer to the presence of open water bodies. At present the land-water fraction in the GEM model is specified by means of static geophysical databases which do not change annually. Uncertainty is introduced into this land-water fraction and the sensitivity of the resulting soil moisture and precipitation is quantified for a series of convective precipitation events over Alberta for the summer 2014 period.

  18. Does Ice Matter? Heavy Rainfall from Warm and Mixed-phase Convection in COPE

    NASA Astrophysics Data System (ADS)

    Leon, David.; Lasher-Trapp, Sonia; French, Jeffrey; Blyth, Alan; Bennett, Lindsay; Brown, Phil

    2014-05-01

    The COnvective Precipitation E experiment (COPE), which took place over the southwestern peninsula of the UK in Summer 2013, was motivated by a number of convective storms that produced flash flooding, chief among them the Boscastle flood event of 2004. Cloud tops during the Boscastle flood reached temperatures of -15 to -20 °C. Coupled with possible seeding from aloft, it was reasonable to presume that ice processes played an important role in precipitation formation. Some heavy precipitation events were sampled by the suite of ground-based and airborne instruments assembled for COPE, despite the unusually warm and dry weather in the UK at that time. Convective cells during several of these events had tops below the freezing level, or not far above where no ice was observed by the aircraft. Impressively, heavy rainfall was observed at the ground-based X-band radar with reflectivities frequently exceedeeding +60 dBZ. Here we use new in situ observations from the University of Wyoming King Air and the Wyoming Cloud Radar to corroborate reflectivity from the ground-based X-band radar. These observations, along with atmospheric soundings and calculations from a 1D warm rain model, are also utilized to understand the dynamic, thermodynamic and microphysical structure of these heavily precipitating convective cells. These observations lead us to question the prevalent assumption that ice processes are critical to the production of heavy convective precipitation.

  19. Initiation of deep convection along boundary layer convergence lines in a semitropical environment

    SciTech Connect

    Fankhauser, J.C.; Crook, N.A.; Tuttle, J.; Miller, L.J.; Wade, C.G.

    1995-02-01

    The initiation of deep convection through forcing along boundary layer convergence lines is examined using observations from the Convection and Precipitation/Electrification (CaPE) Experiment conducted in east-central Florida during the summer of 1991. The study is concerned with the evolution and interaction of two converging air masses that were initially separated by an intervening boundary layer characterized by neutral stability and horizontal convective rolls. As anticipated, major thunderstorms erupt when the east coast breeze eventually collides with thunderstorm outflows from the west, but unexpected convection takes place prior to their merger along a well-defined confluence zone associated with a persistent quasi-stationary roll vortex signature. In this study, complementary interactions between roll vortex convergence lines and the sea-breeze front are not sufficient to trigger deep convection. However, organized convergence along the eastward-spreading thunderstorm outflows did interact periodically with roll vortex convergence maxima to initiate a new series of new storms. Results from two-dimensional numerical model simulations replicate many of the observed boundary layer features. Surface heating produces circulations similar to sea-breeze frontal zones that appear near the coastlines and progress steadily toward each other as the interior boundary layer deepens. Vertical velocity maxima develop over the associated convergence zones, but weaker periodic maxima also occur within the interior air mass at intervals similar to the spacing of observed horizontal roll vortices.

  20. Contrasting ice microphysical properties of wintertime frontal clouds and summertime convective clouds

    NASA Astrophysics Data System (ADS)

    Wu, W.; McFarquhar, G. M.

    2015-12-01

    The microphysical and optical properties of ice clouds were derived from measurements collected during the Colorado Airborne Multi-phase Cloud Study (CAMPS) and the Storm Peak Laboratory Cloud Property Validation Experiment (STORMVEX) conducted in the winter of 2010-2011 over the Rocky Mountains and during the Midlatitude Continental Convective Clouds Experiment (MC3E) conducted in the summer of 2011 over Oklahoma. A two-dimensional cloud (2DC) probe, two-dimensional precipitation (2DP) probe and Fast 2DC probe were installed on the University of Wyoming King Air aircraft during CAMPS and a Cloud Imaging Probe (CIP) and Precipitation Imaging Probe were operated on the ground at the Storm Peak Laboratory during STORMVEX. A 2DC, CIP and a high volume precipitation spectrometer were installed in the University of North Dakota Citation aircraft during MC3E. The distributions of particle habits, number distribution functions, total number concentrations, ice water contents, precipitation rates, extinction and effective radius from four cases of wintertime frontal clouds sampled during CAMPS/STORMVEX and from four cases of the stratiform region of summer convective systems from MC3E are compared. It is found that there is higher percentage of pristine ice particles, such as dendrites and columns, in the wintertime frontal clouds than in the summertime convective clouds, where the dominant habits are rimed particles. The number distribution functions are generally broader in the summertime clouds than in the wintertime frontal clouds. In addition, the number concentrations and ice water contents are generally lower in the wintertime frontal clouds than in the summertime convective clouds when comparing the same temperature ranges. Implications about the potential microphysical processes that are acting in these two types of ice clouds are discussed. The results in this study are also compared with previous studies using data from other field campaigns.

  1. The Dynamics of Titan's Convective Clouds

    NASA Astrophysics Data System (ADS)

    Rafkin, S. C.

    2012-12-01

    Titan's deep convective clouds are the most dynamic phenomena known to operate within the atmosphere of the moon. Previous studies have focused primarily on the control of these storms by the large scale thermodynamic environment, especially methane abundance, which determines the amount of convective available potential energy (CAPE). This study looks at factors in addition to the thermodynamic environment that may have a first order impact on the evolution and structure of Titan's deep convective clouds. To the extent that thunderstorms on Earth provide a reasonable analog to the storms on Titan, it is well established that CAPE alone is insufficient to determine the structure and behavior of deep convection. Wind shear—both directional and speed—is also known to exert a first order effect. The influence of both CAPE and wind speed shear is typically expressed as the ratio of the two parameters in the form of the Bulk Richardson Number. On Earth, for a fixed value of CAPE, the addition of wind speed shear (i.e., the reduction of the Bulk Richardson Number) will tend to produce storms that are longer lived, tilted upshear with height, and multi-cellular in nature. These multi-cellular storms also tend to be more violent than storms generated in low wind speed shear environments: strong winds and large hail are common. The addition of directional shear (i.e., helicity) can transform the multi-cell storms into single, intense supercell storms. These are the storms associated typically associated with tornadoes. With respect to Titan, if there is a similar dependence on the Bulk Richardson Number, then this would have implications for how long Titan's storms live, how much precipitation they can produce, the area they cover, and the strength and duration of winds. A series of numerical simulations of Titan's deep convective clouds from the Titan Regional Atmospheric Modeling System are presented. A reasonable sweep of the parameter space of CAPE and shear for

  2. Towards European-scale convection-resolving climate simulations with GPUs: a study with COSMO 4.19

    NASA Astrophysics Data System (ADS)

    Leutwyler, David; Fuhrer, Oliver; Lapillonne, Xavier; Lüthi, Daniel; Schär, Christoph

    2016-09-01

    The representation of moist convection in climate models represents a major challenge, due to the small scales involved. Using horizontal grid spacings of O(1km), convection-resolving weather and climate models allows one to explicitly resolve deep convection. However, due to their extremely demanding computational requirements, they have so far been limited to short simulations and/or small computational domains. Innovations in supercomputing have led to new hybrid node designs, mixing conventional multi-core hardware and accelerators such as graphics processing units (GPUs). One of the first atmospheric models that has been fully ported to these architectures is the COSMO (Consortium for Small-scale Modeling) model.Here we present the convection-resolving COSMO model on continental scales using a version of the model capable of using GPU accelerators. The verification of a week-long simulation containing winter storm Kyrill shows that, for this case, convection-parameterizing simulations and convection-resolving simulations agree well. Furthermore, we demonstrate the applicability of the approach to longer simulations by conducting a 3-month-long simulation of the summer season 2006. Its results corroborate the findings found on smaller domains such as more credible representation of the diurnal cycle of precipitation in convection-resolving models and a tendency to produce more intensive hourly precipitation events. Both simulations also show how the approach allows for the representation of interactions between synoptic-scale and meso-scale atmospheric circulations at scales ranging from 1000 to 10 km. This includes the formation of sharp cold frontal structures, convection embedded in fronts and small eddies, or the formation and organization of propagating cold pools. Finally, we assess the performance gain from using heterogeneous hardware equipped with GPUs relative to multi-core hardware. With the COSMO model, we now use a weather and climate model that

  3. Characterization of Mediterranean hail-bearing storms using an operational polarimetric X-band radar

    NASA Astrophysics Data System (ADS)

    Vulpiani, G.; Baldini, L.; Roberto, N.

    2015-07-01

    This work documents the fruitul use of X-band radar observations for the monitoring of severe storms in an operational framework. More specifically, a couple of severe hail-bearing Mediterranean storms occurred in 2013 in southern Italy, flooding two important cities of Sicily, are described in terms of their polarimetric radar signatures and retrieved rainfall fields. It is used the X-band dual-polarization radar operating inside the Catania airport (Sicily, Italy), managed by the Italian Department of Civil Protection. A suitable processing is applied to X-band radar measurements. The crucial procedural step relies on the differential phase processing based on an iterative approach that uses a very short-length (1 km) moving window allowing to properly catch the observed high radial gradients of the differential phase. The parameterization of the attenuation correction algorithm, which use the reconstructed differential phase shift, is derived from electromagnetic simulations based on 3 years of DSD observations collected in Rome (Italy). A Fuzzy Logic hydrometeor classification algorithm was also adopted to support the analysis of the storm characteristics. The precipitation fields amount were reconstructed using a combined polarimetric rainfall algorithm based on reflectivity and specific differential phase. The first considered storm was observed on the 21 February, when a winter convective system, originated in the Tyrrhenian sea, hit only marginally the central-eastern coastline of Sicily causing the flash-flood of Catania. Due to the optimal radar location (the system is located at just few kilometers from the city center), it was possible to well retrieve the storm characteristics, including the amount of rainfall field at ground. Extemporaneous signal extinction, caused by close-range hail core causing significant differential phase shift in very short range path, is documented. The second storm, occurred on 21 August 2013, is a summer mesoscale

  4. Characterization of Mediterranean hail-bearing storms using an operational polarimetric X-band radar

    NASA Astrophysics Data System (ADS)

    Vulpiani, G.; Baldini, L.; Roberto, N.

    2015-11-01

    storm, on 21 August 2013, was a summer mesoscale convective system that originated from a Mediterranean low pressure system lasting a few hours that eventually flooded the city of Syracuse. The undergoing physical process, including the storm dynamics, is inferred by analyzing the vertical sections of the polarimetric radar measurements. The high registered amount of precipitation was fairly well reconstructed, although with a trend toward underestimation at increasing distances. Several episodes of signal extinction were clearly manifested during the mature stage of the observed supercells.

  5. Report of convective phenomena team

    NASA Technical Reports Server (NTRS)

    Orville, H.; Koenig, R.; Miller, J.; Telford, J.; Jones, B.; Alger, G.; Lee, R.; Boudle, D.

    1980-01-01

    A group meeting was assembled to focus on the planning of specific experiments, to establish some priorities, identify interested scientists who would like to participate, establish any special requirements, make recommendations on data processing, and to prepare flight plan outlines. Since the number of convective storms in the CCOPE (Cooperative Convective Precipitation Experiment) field experiment area are limited to only a few days during the operational time period the flight plans must be designed with a hierarchy of abort experiments so that the easily identified and lowest probability events should take priority until their quota is filled.

  6. Kinetic energy budget studies of areas of convection

    NASA Technical Reports Server (NTRS)

    Fuelberg, H. E.

    1979-01-01

    Synoptic-scale kinetic energy budgets are being computed for three cases when large areas of intense convection occurred over the Central United States. Major energy activity occurs in the storm areas.

  7. Storm diagnostic/predictive images derived from a combination of lightning and satellite imagery

    NASA Technical Reports Server (NTRS)

    Goodman, Steven J.; Buechler, Dennis E.; Meyer, Paul J.

    1988-01-01

    A technique is presented for generating trend or convective tendency images using a combination of GOES satellite imagery and cloud-to-ground lightning observations. The convective tendency images can be used for short term forecasting of storm development. A conceptual model of cloud electrical development and an example of the methodology used to generate lightning/satellite convective tendency imagery are given. Successive convective tendency images can be looped or animated to show the previous growth or decay of thunderstorms and their associated lighting activity. It is suggested that the convective tendency image may also be used to indicate potential microburst producing storms.

  8. Methane Storms and Rain on Titan's Atmosphere from Numerical Simulations

    NASA Astrophysics Data System (ADS)

    Hueso, Ricardo; Sánchez-Lavega, A.

    2006-09-01

    Under the pressure-temperature conditions on Titan, methane, a large atmospheric component amounting perhaps to a 3-5% of the atmosphere, is close to its triple point, potentially playing a similar role as water on Earth. The Huygens probe and Cassini radar images have shown a terrain shaped by erosion of probably liquid origin, suggestive of past rain. On the other hand, Voyager IRIS spectroscopic observations of Titan indicate that methane saturation occurs amounting perhaps to 150%, suggesting that the satellite should regularly be covered by methane clouds. Telescopic observations from the Earth and Cassini have shown that clouds are localized, transient and fast evolving, in particular in the South Polar Region (currently in its summer season until its autumn equinox in 2008). To explain these observations, we investigate different scenarios of moist convective storms on Titan using a three-dimensional cloud resolving model that incorporates microphysics and allows computing the precipitation that reaches the surface as a function of the concentration of cloud condensation nuclei in the atmosphere. We show that under the appropriate conditions, precipitation rates comparable to intense tropical storms on Earth could take place. A typical storm may form when the methane humidity is on the order of 80%, developing vertical velocities of 20 ms-1 with the updrafts reaching up to 30 km height during a total life-span of a few hours, producing maximum precipitation rates of 100 kgm-2, that are comparable to flash-floods on Earth. Acknowledgements: This work has been funded by Spanish MCYT PNAYA2003-03216, fondos FEDER and Grupos UPV 15946/2004. R. Hueso acknowledges an RyC research contract form the Spanish MEC.

  9. Tropical Storm Katrina

    Atmospheric Science Data Center

    2014-05-15

    ... title:  Cloud Spirals and Outflow in Tropical Storm Katrina     View Larger Image ... heights and cloud-tracked wind velocities for Tropical Storm Katrina, as the center of the storm was situated over the Tennessee ...

  10. Current understanding of magnetic storms: Storm-substorm relationships

    SciTech Connect

    Kamide, Y.; Gonzalez, W.D.; Baumjohann, W.; Daglis, I.A.; Grande, M.; Joselyn, J.A.; Singer, H.J.; McPherron, R.L.; Phillips, J.L.; Reeves, E.G.; Rostoker, G.; Sharma, A.S.; Tsurutani, B.T.

    1998-08-01

    the storm-time ring current. An apparently new controversy regarding the relative importance of the two processes is thus created. It is important to identify the role of substorm occurrence in the large-scale enhancement of magnetospheric convection driven by solar wind electric fields. (3) Numerical schemes for predicting geomagnetic activity indices on the basis of solar/solar wind/interplanetary magnetic field parameters continue to be upgraded, ensuring reliable techniques for forecasting magnetic storms under real-time conditions. There is a need to evaluate the prediction capability of geomagnetic indices on the basis of physical processes that occur during storm time substorms. (4) It is crucial to differentiate between storms and nonstorm time substorms in terms of energy transfer/conversion processes, i.e., mechanical energy from the solar wind, electromagnetic energy in the magnetotail, and again, mechanical energy of particles in the plasma sheet, ring current, and aurora. To help answer the question of the role of substorms in energizing ring current particles, it is crucial to find efficient magnetospheric processes that heat ions up to some minimal energies so that they can have an effect on the strength of the storm time ring current. (5) The question of whether the {ital Dst} index is an accurate and effective measure of the storm time ring-current is also controversial. In particular, it is demonstrated that the dipolarization effect associated with substorm expansion acts to reduce the {ital Dst} magnitude, even though the ring current may still be growing. {copyright} 1998 American Geophysical Union

  11. Severe convection features in the Amazon Basin: a TRMM-based 15-year evaluation

    NASA Astrophysics Data System (ADS)

    Pereira Nunes, Ana; Silva Dias, Maria; Anselmo, Evandro; Rodriguez, Carlos

    2016-04-01

    Rainfall in the Amazon Basin is very heterogeneous, mainly because the area encompassed is quite large. Among the systems responsible for rainfall, some stand out as extreme storm events. This study presents a criterion for identifying potentially severe convection in the Amazon region from the Tropical Rainfall Measuring Mission (TRMM) database, specifically from Precipitation Features (PF) - 1998-2012 - generated and stored by the University of Utah. The seasonal and spatial distributions are similar to distributions of Mesoscale Convective Systems already catalogued in previous studies based on GOES satellite images. The seasons with the highest number of cases are austral spring, winter, and fall. With the Amazon region divided into six subregions and cases accumulated by quarter (JFM, AMJ, JAS, OND) the south of the Amazon subregion (SA) accounts for the largest number of cases with the OND quarter with higher occurrence and the lowest in AMJ. Different diurnal cycles of potentially severe convection are observed across the region with the more western areas, closer to the Andes, favoring nighttime cases, especially in the austral spring and summer. The diurnal cycle of the number of the most extreme cases is more pronounced than the diurnal cycle when a large collection of deep convection cases are included.

  12. Rocket dust storms and detached layers in the Martian atmosphere

    NASA Astrophysics Data System (ADS)

    Spiga, A.; Faure, J.; Madeleine, J.; Maattanen, A. E.; Forget, F.

    2012-12-01

    Airborne dust is the main climatic agent in the Martian environment. Local dust storms play a key role in the dust cycle; yet their life cycle is poorly known. Here we use mesoscale modeling with radiatively-active transported dust to predict the evolution of a local dust storm monitored by OMEGA onboard Mars Express. We show that the evolution of this dust storm is governed by deep convective motions. The supply of convective energy is provided by the absorption of incoming sunlight by dust particles, in lieu of latent heating in moist convection on Earth. We propose to use the terminology "rocket dust storm", or conio-cumulonimbus, to describe those storms in which rapid and efficient vertical transport takes place, injecting dust particles at high altitudes in the Martian troposphere (30 to 50 km). Combined to horizontal transport by large-scale winds, rocket dust storms form detached layers of dust reminiscent of those observed with instruments onboard Mars Global Surveyor and Mars Reconnaissance Orbiter. Detached layers are stable over several days owing to nighttime sedimentation being unable to counteract daytime convective transport, and to the resupply of convective energy at sunrise. The peak activity of rocket dust storms is expected in low-latitude regions at clear season, which accounts for the high-altitude tropical dust maximum unveiled by Mars Climate Sounder. Our findings on dust-driven deep convection have strong implications for the Martian dust cycle, thermal structure, atmospheric dynamics, cloud microphysics, chemistry, and robotic and human exploration.ensity-scaled dust optical depth at local times 1400 1600 and 1800 (lat 2.5°S, Ls 135°) hortwave heating rate at local time 1500 and latitude 2.5°S.

  13. The effects of storms and storm-generated currents on sand beaches in Southern Maine, USA

    USGS Publications Warehouse

    Hill, H.W.; Kelley, J.T.; Belknap, D.F.; Dickson, S.M.

    2004-01-01

    Storms are one of the most important controls on the cycle of erosion and accretion on beaches. Current meters placed in shoreface locations of Saco Bay and Wells Embayment, ME, recorded bottom currents during the winter months of 2000 and 2001, while teams of volunteers profiled the topography of nearby beaches. Coupling offshore meteorological and beach profile data made it possible to determine the response of nine beaches in southern Maine to various oceanographic and meteorological conditions. The beaches selected for profiling ranged from pristine to completely developed and permitted further examination of the role of seawalls on the response of beaches to storms. Current meters documented three unique types of storms: frontal passages, southwest storms, and northeast storms. In general, the current meter results indicate that frontal passages and southwest storms were responsible for bringing sediment towards the shore, while northeast storms resulted in a net movement of sediment away from the beach. During the 1999-2000 winter, there were a greater percentage of frontal passages and southwest storms, while during the 2000-2001 winter, there were more northeast storms. The sediment that was transported landward during the 1999-2000 winter was reworked into the berm along moderately and highly developed beaches during the next summer. A northeast storm on March 5-6, 2001, resulted in currents in excess of 1 m s-1 and wave heights that reached six meters. The storm persisted over 10 high tides and caused coastal flooding and property damage. Topographic profiles made before and after the storm demonstrate that developed beaches experienced a loss of sediment volume during the storm, while sediment was redistributed along the profile on moderately developed and undeveloped beaches. Two months after the storm, the profiles along the developed beaches had not reached their pre-storm elevation. In comparison, the moderately developed and undeveloped beaches

  14. 3-Dimensional simulations of storm dynamics on Saturn

    NASA Astrophysics Data System (ADS)

    Hueso, R.; Sanchez-Lavega, A.

    2000-10-01

    The formation and evolution of convective clouds in the atmosphere of Saturn is investigated using an anelastic three-dimensional time-dependent model with parameterized microphysics. The model is designed to study the development of moist convection on any of the four giant planets and has been previously used to investigate the formation of water convective storms in the jovian atmosphere. The role of water and ammonia in moist convection is investigated with varying deep concentrations. Results imply that most of the convective activity observed at Saturn may occur at the ammonia cloud deck while the formation of water moist convection may happen only when very strong constraints on the lower troposphere are met. Ammonia storms can ascend to the 300 mb level with vertical velocities around 30 ms-1. The seasonal effect on the thermal profile at the upper troposphere may have important effects on the development of ammonia storms. In the cases where water storms can develop they span many scale heights with peak vertical velocities around 160 ms-1 and cloud particles can be transported up to the 150 mb level. These predicted characteristics are similar to the Great White Spots observed in Saturn which, therefore, could be originated at the water cloud base level. This work has been supported by Gobierno Vasco PI 1997-34. R. Hueso acknowledges a PhD fellowship from Gobierno Vasco.

  15. Research Opportunities at Storm Peak Laboratory

    NASA Astrophysics Data System (ADS)

    Hallar, A. G.; McCubbin, I. B.

    2006-12-01

    The Desert Research Institute (DRI) operates a high elevation facility, Storm Peak Laboratory (SPL), located on the west summit of Mt. Werner in the Park Range near Steamboat Springs, Colorado at an elevation of 3210 m MSL (Borys and Wetzel, 1997). SPL provides an ideal location for long-term research on the interactions of atmospheric aerosol and gas- phase chemistry with cloud and natural radiation environments. The ridge-top location produces almost daily transition from free tropospheric to boundary layer air which occurs near midday in both summer and winter seasons. Long-term observations at SPL document the role of orographically induced mixing and convection on vertical pollutant transport and dispersion. During winter, SPL is above cloud base 25% of the time, providing a unique capability for studying aerosol-cloud interactions (Borys and Wetzel, 1997). A comprehensive set of continuous aerosol measurements was initiated at SPL in 2002. SPL includes an office-type laboratory room for computer and instrumentation setup with outside air ports and cable access to the roof deck, a cold room for precipitation and cloud rime ice sample handling and ice crystal microphotography, a 150 m2 roof deck area for outside sampling equipment, a full kitchen and two bunk rooms with sleeping space for nine persons. The laboratory is currently well equipped for aerosol and cloud measurements. Particles are sampled from an insulated, 15 cm diameter manifold within approximately 1 m of its horizontal entry point through an outside wall. The 4 m high vertical section outside the building is capped with an inverted can to exclude large particles.

  16. Application of new methods based on ECMWF ensemble model for predicting severe convective weather situations

    NASA Astrophysics Data System (ADS)

    Lazar, Dora; Ihasz, Istvan

    2013-04-01

    The short and medium range operational forecasts, warning and alarm of the severe weather are one of the most important activities of the Hungarian Meteorological Service. Our study provides comprehensive summary of newly developed methods based on ECMWF ensemble forecasts to assist successful prediction of the convective weather situations. . In the first part of the study a brief overview is given about the components of atmospheric convection, which are the atmospheric lifting force, convergence and vertical wind shear. The atmospheric instability is often used to characterize the so-called instability index; one of the most popular and often used indexes is the convective available potential energy. Heavy convective events, like intensive storms, supercells and tornadoes are needed the vertical instability, adequate moisture and vertical wind shear. As a first step statistical studies of these three parameters are based on nine years time series of 51-member ensemble forecasting model based on convective summer time period, various statistical analyses were performed. Relationship of the rate of the convective and total precipitation and above three parameters was studied by different statistical methods. Four new visualization methods were applied for supporting successful forecasts of severe weathers. Two of the four visualization methods the ensemble meteogram and the ensemble vertical profiles had been available at the beginning of our work. Both methods show probability of the meteorological parameters for the selected location. Additionally two new methods have been developed. First method provides probability map of the event exceeding predefined values, so the incident of the spatial uncertainty is well-defined. The convective weather events are characterized by the incident of space often rhapsodic occurs rather have expected the event area can be selected so that the ensemble forecasts give very good support. Another new visualization tool shows time

  17. Supergranular Convection

    NASA Astrophysics Data System (ADS)

    Udayashankar, Paniveni

    2015-12-01

    Observation of the Solar photosphere through high resolution instruments have long indicated that the surface of the Sun is not a tranquil, featureless surface but is beset with a granular appearance. These cellular velocity patterns are a visible manifestation of sub- photospheric convection currents which contribute substantially to the outward transport of energy from the deeper layers, thus maintaining the energy balance of the Sun as a whole.Convection is the chief mode of transport in the outer layers of all cool stars such as the Sun (Noyes,1982). Convection zone of thickness 30% of the Solar radius lies in the sub-photospheric layers of the Sun. Here the opacity is so large that heat flux transport is mainly by convection rather than by photon diffusion. Convection is revealed on four scales. On the scale of 1000 km, it is granulation and on the scale of 8-10 arcsec, it is Mesogranulation. The next hierarchial scale of convection , Supergranules are in the range of 30-40 arcsec. The largest reported manifestation of convection in the Sun are ‘Giant Cells’or ‘Giant Granules’, on a typical length scale of about 108 m.'Supergranules' is caused by the turbulence that extends deep into the convection zone. They have a typical lifetime of about 20hr with spicules marking their boundaries. Gas rises in the centre of the supergranules and then spreads out towards the boundary and descends.Broadly speaking supergranules are characterized by the three parameters namely the length L, the lifetime T and the horizontal flow velocity vh . The interrelationships amongst these parameters can shed light on the underlying convective processes and are in agreement with the Kolmogorov theory of turbulence as applied to large scale solar convection (Krishan et al .2002 ; Paniveni et. al. 2004, 2005, 2010).References:1) Noyes, R.W., The Sun, Our Star (Harvard University Press, 1982)2) Krishan, V., Paniveni U., Singh , J., Srikanth R., 2002, MNRAS, 334/1,2303) Paniveni

  18. Large Eddy Simulations of Severe Convection Induced Turbulence

    NASA Technical Reports Server (NTRS)

    Ahmad, Nash'at; Proctor, Fred

    2011-01-01

    Convective storms can pose a serious risk to aviation operations since they are often accompanied by turbulence, heavy rain, hail, icing, lightning, strong winds, and poor visibility. They can cause major delays in air traffic due to the re-routing of flights, and by disrupting operations at the airports in the vicinity of the storm system. In this study, the Terminal Area Simulation System is used to simulate five different convective events ranging from a mesoscale convective complex to isolated storms. The occurrence of convection induced turbulence is analyzed from these simulations. The validation of model results with the radar data and other observations is reported and an aircraft-centric turbulence hazard metric calculated for each case is discussed. The turbulence analysis showed that large pockets of significant turbulence hazard can be found in regions of low radar reflectivity. Moderate and severe turbulence was often found in building cumulus turrets and overshooting tops.

  19. The relative contributions of summer and cool-season precipitation to groundwater recharge, Spring Mountains, Nevada, USA

    USGS Publications Warehouse

    Winograd, I.J.; Riggs, A.C.; Coplen, T.B.

    1998-01-01

    A comparison of the stable-isotope signatures of spring waters, snow, snowmelt, summer (July thru September) rain, and cool season (October thru June) rain indicates that the high-intensity, short-duration summer convective storms, which contribute approximately a third of the annual precipitation to the Spring Mountains, provide only a small fraction (perhaps 10%) of the recharge to this major upland in southern Nevada, USA. Late spring snowmelt is the principal means of recharging the fractured Paleozoicage carbonate rocks comprising the central and highest portion of the Spring Mountains. Daily discharge measurements at Peak Spring Canyon Creek during the period 1978-94 show that snowpacks were greatly enhanced during E1 Nin??o events.

  20. Convective initiation in the vicinity of the subtropical Andes

    NASA Astrophysics Data System (ADS)

    Rasmussen, K. L.; Houze, R.

    2014-12-01

    Extreme convection tends to form in the vicinity of mountain ranges, and the Andes in subtropical South America help spawn some of the most intense convection in the world. An investigation of the most intense storms for 11 years of TRMM Precipitation Radar (PR) data shows a tendency for squall lines to initiate and develop in this region with the canonical leading convective line/trailing stratiform structure. The synoptic environment and structures of the extreme convection and MCSs in subtropical South America are similar to those found in other regions of the world, especially the United States. In subtropical South America, however, the topographical influence on the convective initiation and maintenance of the MCSs is unique. A capping inversion in the lee of the Andes is important in preventing premature triggering. The Andes and other mountainous terrain of Argentina focus deep convective initiation in a narrow region. Subsequent to initiation, the convection often evolves into propagating mesoscale convective systems similar to those seen over the Great Plains of the U. S. and produces damaging tornadoes, hail, and floods across a wide agricultural region. Numerical simulations conducted with the NCAR Weather Research and Forecasting (WRF) Model extend the observational analysis and provide an objective evaluation of storm initiation, terrain effects, and development mechanisms. The simulated mesoscale systems closely resemble the storm structures seen by the TRMM Precipitation Radar as well as the overall shape and character of the storms shown in GOES satellite data. A sensitivity experiment with different configurations of topography, including both decreasing and increasing the height of the Andes Mountains, provides insight into the significant influence of orography in focusing convective initiation in this region. Lee cyclogenesis and a strong low-level jet are modulated by the height of the Andes Mountains and directly affect the character

  1. Nowcasting, warning, mitigation, and documentation of hail storms in Styria, Austria

    NASA Astrophysics Data System (ADS)

    Teschl, Franz; Teschl, Reinhard; Paulitsch, Helmut; Randeu, Walter L.

    2013-04-01

    The South-East of the Austrian province of Styria is a hail-hotspot. Typically on more than 50 days in summer hail warnings are released. Since decades, hail mitigation actions are carried out by means of specially equipped aircraft seeding 'suspicious' clouds with silver-iodide generators. In the year 2009, a project was started with the goal to document hail events and to increase the efficiency of hail finding measures. Since decades, the weather situation is observed in this region by the Austrian C-band weather radar network that provides every five minutes updated 3D reflectivity and velocity measurements with a resolution of 1 km. In 2009, the aircraft used for cloud seeding have been equipped with GPS sensors and tablet PCs. As a consequence, the position of the aircraft is accessible in close to real time and can be marked in the weather radar images. Further, the aircraft pilots have access to the current weather radar images. This idea guarantees a two-way information exchange. On the one hand, the pilots get a full picture of the overall weather situation. On the other hand, it can be documented what cloud cells the experienced aircraft pilots regarded as critical and when and where they chose to seed. Since the project started, aircraft seeding has been documented on more than 150 days. This study analyzes convective storms as they were tracked with the weather radar during their life cycle - from the origin to the collapse. Both categories of cells, seeded and unseeded ones, have been analyzed. The duration, the path-length of the track over ground, the vertical profile, the zero-degree isotherm, as well as the precipitation rate have been extracted. These datasets will allow the evaluation of forecast models for convective storms. It was further evaluated if the seeded convective storms met standardized seeding criteria. A long term perspective of the ongoing project is a scientific analysis of the effects of the hail suppression measures based on

  2. Convection towers

    DOEpatents

    Prueitt, Melvin L.

    1996-01-01

    Convection towers which are capable of cleaning the pollution from large quantities of air, of generating electricity, and of producing fresh water utilize the evaporation of water sprayed into the towers to create strong airflows and to remove pollution from the air. Turbines in tunnels at the skirt section of the towers generate electricity, and condensers produce fresh water.

  3. Convection towers

    DOEpatents

    Prueitt, Melvin L.

    1995-01-01

    Convection towers which are capable of cleaning the pollution from large quantities of air, of generating electricity, and of producing fresh water utilize the evaporation of water sprayed into the towers to create strong airflows and to remove pollution from the air. Turbines in tunnels at the skirt section of the towers generate electricity, and condensers produce fresh water.

  4. Convection towers

    DOEpatents

    Prueitt, M.L.

    1996-01-16

    Convection towers which are capable of cleaning the pollution from large quantities of air, of generating electricity, and of producing fresh water utilize the evaporation of water sprayed into the towers to create strong airflows and to remove pollution from the air. Turbines in tunnels at the skirt section of the towers generate electricity, and condensers produce fresh water. 6 figs.

  5. Convection towers

    DOEpatents

    Prueitt, Melvin L.

    1994-01-01

    Convection towers which are capable of cleaning the pollution from large quantities of air and of generating electricity utilize the evaporation of water sprayed into the towers to create strong airflows and to remove pollution from the air. Turbines in tunnels at the skirt section of the towers generate electricity. Other embodiments may also provide fresh water, and operate in an updraft mode.

  6. Modeling Convection

    ERIC Educational Resources Information Center

    Ebert, James R.; Elliott, Nancy A.; Hurteau, Laura; Schulz, Amanda

    2004-01-01

    Students must understand the fundamental process of convection before they can grasp a wide variety of Earth processes, many of which may seem abstract because of the scales on which they operate. Presentation of a very visual, concrete model prior to instruction on these topics may facilitate students' understanding of processes that are largely…

  7. Tropical Storm Bud

    Atmospheric Science Data Center

    2013-04-19

    article title:  A Strengthening Eastern Pacific Storm     View Larger Image ... Imaging SpectroRadiometer (MISR) show then Tropical Storm Bud as it was intensifying toward hurricane status, which it acquired ...

  8. Spectral characteristics of mid-latitude continental convection from a global variable-resolution Voronoi-mesh atmospheric model

    NASA Astrophysics Data System (ADS)

    Wong, M.; Skamarock, W. C.

    2015-12-01

    Global numerical weather forecast tests were performed using the global nonhydrostatic atmospheric model, Model for Prediction Across Scales (MPAS), for the NOAA Storm Prediction Center 2015 Spring Forecast Experiment (May 2015) and the Plains Elevated Convection at Night (PECAN) field campaign (June to mid-July 2015). These two sets of forecasts were performed on 50-to-3 km and 15-to-3 km smoothly-varying horizontal meshes, respectively. Both variable-resolution meshes have nominal convection-permitting 3-km grid spacing over the entire continental US. Here we evaluate the limited-area (vs. global) spectra from these NWP simulations. We will show the simulated spectral characteristics of total kinetic energy, vertical velocity variance, and precipitation during these spring and summer periods when diurnal continental convection is most active over central US. Spectral characteristics of a high-resolution global 3-km simulation (essentially no nesting) from the 20 May 2013 Moore, OK tornado case are also shown. These characteristics include spectral scaling, shape, and anisotropy, as well as the effective resolution of continental convection representation in MPAS.

  9. Summer Astronomy

    ERIC Educational Resources Information Center

    Riddle, Bob

    2004-01-01

    This brief article describes what can be expected of the skies in the summer of 2004 with quite a few celestial thrills to anticipate. In addition to the planet viewing opportunities, there is a very rare Venus transit of the Sun and the annual Perseid meteor shower. The 2004 summer also marks both an end and beginning for the Cassini/Huygens…

  10. Climatological characteristics of deep and shallow precipitation clouds in summer over the Tibetan Plateau

    NASA Astrophysics Data System (ADS)

    Pan, Xiao; Fu, Yunfei

    2016-04-01

    The Tibetan Plateau (TP) is the highest plateau with complex terrain in the world, and it can affect the weather and climate of many regions through its mechanical and thermal effects. The precipitation types over TP are divided into deep (strong deep convection and weak deep convection) and shallow precipitations, according to the particular atmospheric vertical structures of TP. The climatological characteristics of the deep and shallow precipitations including their horizontal distributions, infrared signal characteristics of clouds, vertical structures, diurnal variations and local phase shifts over TP are investigated by utilizing combining measurements of the tropical rainfall measuring mission (TRMM) precipitation radar (PR) and visible and infrared scanner (VIRS) in summer from 1998 to 2007. The results show that the precipitation over TP is mainly in the form of weak deep convection, which occupies 67.8% of total rain, then followed by shallow precipitation with 26.4% and the strong deep convection with 5.8%. The clouds for strong deep convection and weak deep convection are mainly composed of ice and ice-water mixed particles, respectively. The vertical profiles of deep precipitations firstly increase, and then decrease from the storm top altitude to the ground level, with maximizing at about 7.5 km altitude. In contrast, the vertical profile of the shallow precipitation only has an increasing process. The deep precipitations have significant diurnal variations. The precipitation frequencies for strong deep convection and weak deep convection both peak at 16 local time (LT), while the rain intensities for them peak at 13 and 18 LST, respectively. Furthermore, the rain intensity for strong deep convection is characterized by a secondary peak at 00 LT. For the shallow precipitation, the diurnal variation is relatively weaker. The precipitation frequency and intensity both peak at 20 LT, presenting the characteristic of night rain. The diurnal variations of

  11. Urban Heat Islands and Summertime Convective Thunderstorms in Atlanta: Three Case Studies

    NASA Technical Reports Server (NTRS)

    Bornstein, Robert; Lin, Qinglu; Goodman, H. Michael (Technical Monitor)

    1999-01-01

    Data from both 27 sites in the Atlanta mesonet surface meteorological network and eight National Weather Service sites were analyzed for the period from 26 July to 3 August 1996. Analysis of the six precipitation events over the city during the period (each on a different day) showed that its urban heat island (UHI) induced a convergence zone that initiated three of the storms at different times of the day, i.e., 0630,0845, and 1445 EDT. Previous analysis has shown that New York City (NYC) effects summer daytime thunderstorm formation and/or movement. That study found that during nearly calm regional flow conditions the NYC UHI initiates convective activity. Moving thunderstorms, however, tended to bifurcate and to move around the city, due to its building barrier effect. The current Atlanta results thus agree with the NYC results with respect to thunderstorm initiation.

  12. Utilities weather the storm

    SciTech Connect

    Lihach, N.

    1984-11-01

    Utilities must restore power to storm-damaged transmission and distribution systems, even if it means going out in ice storms or during lightning and hurricane conditions. Weather forecasting helps utilities plan for possible damage as well as alerting them to long-term trends. Storm planning includes having trained repair personnel available and adjusting the system so that less power imports are needed. Storm damage response requires teamwork and cooperation between utilities. Utilities can strengthen equipment in storm-prone or vulnerable areas, but good data are necessary to document the incidence of lighning strikes, hurricanes, etc. 2 references, 8 figures.

  13. Observations of Two Sprite-Producing Storms in Colorado

    NASA Technical Reports Server (NTRS)

    Lang, Timothy J.; Lyons, Walter A.; Cummer, Steven A.; Fuchs, Brody R.; Dolan, Brenda; Rutledge, Steven A.; Krehbiel, Paul; Rison, William; Stanley, Mark; Ashcraft, Thomas

    2016-01-01

    Two sprite-producing thunderstorms were observed on 8 and 25 June 2012 in northeastern Colorado by a combination of low-light cameras, a lightning mapping array, polarimetric and Doppler radars, the National Lightning Detection Network, and charge moment change measurements. The 8 June event evolved from a tornadic hailstorm to a larger multicellular system that produced 21 observed positive sprites in 2 h. The majority of sprites occurred during a lull in convective strength, as measured by total flash rate, flash energy, and radar echo volume. Mean flash area spiked multiple times during this period; however, total flash rates still exceeded 60 min(sup 1), and portions of the storm featured a complex anomalous charge structure, with midlevel positive charge near 20degC. The storm produced predominantly positive cloud-to-ground lightning. All sprite-parent flashes occurred on the northeastern flank of the storm, where strong westerly upper level flow was consistent with advection of charged precipitation away from convection, providing a pathway for stratiform lightning. The 25 June event was another multicellular hailstorm with an anomalous charge structure that produced 26 positive sprites in less than 1 h. The sprites again occurred during a convective lull, with relatively weaker reflectivity and lower total flash rate but relatively larger mean flash area. However, all sprite parents occurred in or near convection and tapped charge layers in adjacent anvil cloud. The results demonstrate the sprite production by convective ground strokes in anomalously charged storms and also indicate that sprite production and convective vigor are inversely related in mature storms.

  14. Observations of two sprite-producing storms in Colorado

    NASA Astrophysics Data System (ADS)

    Lang, Timothy J.; Lyons, Walter A.; Cummer, Steven A.; Fuchs, Brody R.; Dolan, Brenda; Rutledge, Steven A.; Krehbiel, Paul; Rison, William; Stanley, Mark; Ashcraft, Thomas

    2016-08-01

    Two sprite-producing thunderstorms were observed on 8 and 25 June 2012 in northeastern Colorado by a combination of low-light cameras, a lightning mapping array, polarimetric and Doppler radars, the National Lightning Detection Network, and charge moment change measurements. The 8 June event evolved from a tornadic hailstorm to a larger multicellular system that produced 21 observed positive sprites in 2 h. The majority of sprites occurred during a lull in convective strength, as measured by total flash rate, flash energy, and radar echo volume. Mean flash area spiked multiple times during this period; however, total flash rates still exceeded 60 min-1, and portions of the storm featured a complex anomalous charge structure, with midlevel positive charge near -20°C. The storm produced predominantly positive cloud-to-ground lightning. All sprite-parent flashes occurred on the northeastern flank of the storm, where strong westerly upper level flow was consistent with advection of charged precipitation away from convection, providing a pathway for stratiform lightning. The 25 June event was another multicellular hailstorm with an anomalous charge structure that produced 26 positive sprites in less than 1 h. The sprites again occurred during a convective lull, with relatively weaker reflectivity and lower total flash rate but relatively larger mean flash area. However, all sprite parents occurred in or near convection and tapped charge layers in adjacent anvil cloud. The results demonstrate the sprite production by convective ground strokes in anomalously charged storms and also indicate that sprite production and convective vigor are inversely related in mature storms.

  15. Interannual similarity in the Martian atmosphere during the dust storm season

    NASA Astrophysics Data System (ADS)

    Kass, D. M.; Kleinböhl, A.; McCleese, D. J.; Schofield, J. T.; Smith, M. D.

    2016-06-01

    We find that during the dusty season on Mars (southern spring and summer) of years without a global dust storm there are three large regional-scale dust storms. The storms are labeled A, B, and C in seasonal order. This classification is based on examining the zonal mean 50 Pa (˜25 km) daytime temperature retrievals from TES/MGS and MCS/MRO over 6 Mars Years. Regional-scale storms are defined as events where the temperature exceeds 200 K. Examining the MCS dust field at 50 Pa indicates that warming in the Southern Hemisphere is dominated by direct heating, while northern high latitude warming is a dynamical response. A storms are springtime planet encircling Southern Hemisphere events. B storms are southern polar events that begin near perihelion and last through the solstice. C storms are southern summertime events starting well after the end of the B storm. C storms show the most interannual variability.

  16. Convection towers

    DOEpatents

    Prueitt, M.L.

    1994-02-08

    Convection towers which are capable of cleaning the pollution from large quantities of air and of generating electricity utilize the evaporation of water sprayed into the towers to create strong airflows and to remove pollution from the air. Turbines in tunnels at the skirt section of the towers generate electricity. Other embodiments may also provide fresh water, and operate in an updraft mode. 5 figures.

  17. Structure and evolution of flash flood producing storms in a small urban watershed

    NASA Astrophysics Data System (ADS)

    Yang, Long; Smith, James; Baeck, Mary Lynn; Smith, Brianne; Tian, Fuqiang; Niyogi, Dev

    2016-04-01

    The objective of this study is to examine the structure and evolution of storms that produce flash floods in "small" urban watersheds. The study site is Harry's Brook, a 1.1 km2 urban watershed in Princeton, New Jersey. A catalog of 15 storms is developed for Harry's Brook based on paired observations of streamflow and rainfall. Lagrangian analyses of storm properties are based on storm tracking procedures utilizing 3-D radar reflectivity observations from the KDIX (Fort Dix, New Jersey) Weather Surveillance Radar, 1988 Doppler. Analyses focus on the storm elements that were responsible for the peak rainfall rates over the watershed. The 22 July 2006 storm, which produced the record flood peak in the catalog (a unit discharge of 26.8 m3 s-1 km-2) was characterized by thunderstorm cells that produced more than 50 cloud-to-ground lightning strikes and "collapsed" over Harry's Brook. The 3 June 2006 storm, which produced the third largest flood peak (a unit discharge of 11.1 m3 s-1 km-2), was a "low-echo centroid" storm with no lightning. We use cloud-to-ground flash rate, echo top height, maximum reflectivity, and height of maximum reflectivity as key variables for characterizing convective intensity. Storm motion is examined through a time series of storm speed and direction. The 22 July 2006 and 3 June 2006 storms provide end-members of storm properties, centering on "convective intensity," which are associated with flash flooding in small urban watersheds. Extreme 1-15 min rainfall rates are produced by warm season convective systems at both ends of the convective intensity spectrum.

  18. Interannual variability of planet-encircling dust storms on Mars

    NASA Technical Reports Server (NTRS)

    Zurek, Richard W.; Martin, Leonard J.

    1993-01-01

    A recent review of earth-based telescopic observations of Mars together with Viking orbiter and lander data are employed to estimate the frequency of occurrence of planet-encircling dust storms over the past century and to test whether the period spanned by the Mariner 9 and Viking missions to Mars is representative of the decades prior to 1950. Both spacecraft and earth-based observations suggest that planet-encircling dust storms on Mars occur during a 'dust storm season' in southern spring and summer. Viking data show that planet-encircling dust storms could have occurred in the past on Mars without being detected from earth during years in which Mars was far from earth during the dust storm season. Planet-encircling storms were absent during the dust storm seasons monitored during several favorable oppositions prior to 1956 and after 1986. The change of a planet-encircling dust storm occurring in any arbitrary Mars year is estimated to be approximately one in three, if this occurrence is random from year to year and yet restricted seasonally to southern spring and summer.

  19. Observation and numerical simulation of a convective initiation during COHMEX

    NASA Technical Reports Server (NTRS)

    Song, J. Aaron; Kaplan, Michael L.

    1991-01-01

    Under a synoptically undisturbed condition, a dual-peak convective lifecycle was observed with the COoperative Huntsville Meteorological EXperiment (COHMEX) observational network over a 24-hour period. The lifecycle included a multicell storm, which lasted about 6 hours, produced a peak rainrate exceeding 100 mm/hr, and initiated a downstream mesoscale convective system. The 24-hour accumulated rainfall of this event was the largest during the entire COHMEX. The downstream mesoscale convective system, unfortunately, was difficult to investigate quantitatively due to the lack of mesoscale observations. The dataset collected near the time of the multicell storm evolution, including its initiation, was one of the best datasets of COHMEX. In this study, the initiation of this multicell storm is chosen as the target of the numerical simulations.

  20. Tropical errors and convection

    NASA Astrophysics Data System (ADS)

    Bechtold, P.; Bauer, P.; Engelen, R. J.

    2012-12-01

    Tropical convection is analysed in the ECMWF Integrated Forecast System (IFS) through tropical errors and their evolution during the last decade as a function of model resolution and model changes. As the characterization of these errors is particularly difficult over tropical oceans due to sparse in situ upper-air data, more weight compared to the middle latitudes is given in the analysis to the underlying forecast model. Therefore, special attention is paid to available near-surface observations and to comparison with analysis from other Centers. There is a systematic lack of low-level wind convergence in the Inner Tropical Convergence Zone (ITCZ) in the IFS, leading to a spindown of the Hadley cell. Critical areas with strong cross-equatorial flow and large wind errors are the Indian Ocean with large interannual variations in forecast errors, and the East Pacific with persistent systematic errors that have evolved little during the last decade. The analysis quality in the East Pacific is affected by observation errors inherent to the atmospheric motion vector wind product. The model's tropical climate and its variability and teleconnections are also evaluated, with a particular focus on the Madden-Julian Oscillation (MJO) during the Year of Tropical Convection (YOTC). The model is shown to reproduce the observed tropical large-scale wave spectra and teleconnections, but overestimates the precipitation during the South-East Asian summer monsoon. The recent improvements in tropical precipitation, convectively coupled wave and MJO predictability are shown to be strongly related to improvements in the convection parameterization that realistically represents the convection sensitivity to environmental moisture, and the large-scale forcing due to the use of strong entrainment and a variable adjustment time-scale. There is however a remaining slight moistening tendency and low-level wind imbalance in the model that is responsible for the Asian Monsoon bias and for too

  1. Effects of Deep Convection on Atmospheric Chemistry

    NASA Technical Reports Server (NTRS)

    Pickering, Kenneth E.

    2007-01-01

    This presentation will trace the important research developments of the last 20+ years in defining the roles of deep convection in tropospheric chemistry. The role of deep convection in vertically redistributing trace gases was first verified through field experiments conducted in 1985. The consequences of deep convection have been noted in many other field programs conducted in subsequent years. Modeling efforts predicted that deep convection occurring over polluted continental regions would cause downstream enhancements in photochemical ozone production in the middle and upper troposphere due to the vertical redistribution of ozone precursors. Particularly large post-convective enhancements of ozone production were estimated for convection occurring over regions of pollution from biomass burning and urban areas. These estimates were verified by measurements taken downstream of biomass burning regions of South America. Models also indicate that convective transport of pristine marine boundary layer air causes decreases in ozone production rates in the upper troposphere and that convective downdrafts bring ozone into the boundary layer where it can be destroyed more rapidly. Additional consequences of deep convection are perturbation of photolysis rates, effective wet scavenging of soluble species, nucleation of new particles in convective outflow, and the potential fix stratosphere-troposphere exchange in thunderstorm anvils. The remainder of the talk will focus on production of NO by lightning, its subsequent transport within convective clouds . and its effects on downwind ozone production. Recent applications of cloud/chemistry model simulations combined with anvil NO and lightning flash observations in estimating NO Introduction per flash will be described. These cloud-resolving case-study simulations of convective transport and lightning NO production in different environments have yielded results which are directly applicable to the design of lightning

  2. CONVECTION REACTOR

    DOEpatents

    Hammond, R.P.; King, L.D.P.

    1960-03-22

    An homogeneous nuclear power reactor utilizing convection circulation of the liquid fuel is proposed. The reactor has an internal heat exchanger looated in the same pressure vessel as the critical assembly, thereby eliminating necessity for handling the hot liquid fuel outside the reactor pressure vessel during normal operation. The liquid fuel used in this reactor eliminates the necessity for extensive radiolytic gas rocombination apparatus, and the reactor is resiliently pressurized and, without any movable mechanical apparatus, automatically regulates itself to the condition of criticality during moderate variations in temperature snd pressure and shuts itself down as the pressure exceeds a predetermined safe operating value.

  3. Characterizing Extreme Ionospheric Storms

    NASA Astrophysics Data System (ADS)

    Sparks, L.; Komjathy, A.; Altshuler, E.

    2011-12-01

    Ionospheric storms consist of disturbances of the upper atmosphere that generate regions of enhanced electron density typically lasting several hours. Depending upon the storm magnitude, gradients in electron density can sometimes become large and highly localized. The existence of such localized, dense irregularities is a major source of positioning error for users of the Global Positioning System (GPS). Consequently, satellite-based augmentation systems have been implemented to improve the accuracy and to ensure the integrity of user position estimates derived from GPS measurements. Large-scale irregularities generally do not pose a serious threat to estimate integrity as they can be readily detected by such systems. Of greater concern, however, are highly localized irregularities that interfere with the propagation of a signal detected by a user measurement but are poorly sampled by the receivers in the system network. The most challenging conditions have been found to arise following disturbances of large magnitude that occur only rarely over the course of a solar cycle. These extremely disturbed conditions exhibit behavior distinct from moderately disturbed conditions and, hence, have been designated "extreme storms". In this paper we examine and compare the behavior of the extreme ionospheric storms of solar cycle 23 (or, more precisely, extreme storms occurring between January 1, 2000, and December 31, 2008), as represented in maps of vertical total electron content. To identify these storms, we present a robust means of quantifying the regional magnitude of an ionospheric storm. Ionospheric storms are observed frequently to occur in conjunction with magnetic storms, i.e., periods of geophysical activity as measured by magnetometers. While various geomagnetic indices, such as the disturbance storm time (Dst) and the planetary Kp index, have long been used to rank the magnitudes of distinct magnetic storms, no comparable, generally recognized index exists for

  4. Long-Lived Storms and Squall Lines on Titan

    NASA Astrophysics Data System (ADS)

    Rafkin, S. C.; Barth, E. L.

    2015-12-01

    The impact of CAPE and wind shear on storms in a Titan-like environment are explored through numerical simulation. Numerical modeling indicates that both large-scale shear and CAPE environment control the dynamics of the clouds. This response to the large-scale environment is analogous to the behavior of deep convective clouds on Earth. The balance between shear and CAPE, as expressed through the bulk Richardson Number (NR), is a good indicator of the response of a storm to its environment. Large NR results in short-lived single cell storms (Figure 1a). As shear increases for a given CAPE, and NR decreases, the storms transition to a multicellular regime. Multicellular storms are longer-lived and are characterized by a downdraft generated cold pool that interacts with the background shear vorticity to initiate cells along the leading edge of the storm gust front (Figure 1b). The most intense multicellular systems simulated in this study behave similar to terrestrial squall lines, and very long-lived storms (>24 hours) propagating for 1000 km or more might be possible. Cloud outbursts and linear cloud features observed from ground and Cassini may be the result of these organized storm systems. Varying amounts of shear in the Titan environment might explain the variety of convective cloud expressions identified in Cassini orbiter and ground-based observations. The resulting distribution and magnitude of precipitation as well as surface winds associated with storms have implications on the formation of fluvial and aeolian features, including dunes, and on the exchange of methane with the surface and lakes.

  5. Factors Associated With Mortality of Thyroid Storm

    PubMed Central

    Ono, Yosuke; Ono, Sachiko; Yasunaga, Hideo; Matsui, Hiroki; Fushimi, Kiyohide; Tanaka, Yuji

    2016-01-01

    Abstract Thyroid storm is a life-threatening and emergent manifestation of thyrotoxicosis. However, predictive features associated with fatal outcomes in this crisis have not been clearly defined because of its rarity. The objective of this study was to investigate the associations of patient characteristics, treatments, and comorbidities with in-hospital mortality. We conducted a retrospective observational study of patients diagnosed with thyroid storm using a national inpatient database in Japan from April 1, 2011 to March 31, 2014. Of approximately 21 million inpatients in the database, we identified 1324 patients diagnosed with thyroid storm. The mean (standard deviation) age was 47 (18) years, and 943 (71.3%) patients were female. The overall in-hospital mortality was 10.1%. The number of patients was highest in the summer season. The most common comorbidity at admission was cardiovascular diseases (46.6%). Multivariable logistic regression analyses showed that higher mortality was significantly associated with older age (≥60 years), central nervous system dysfunction at admission, nonuse of antithyroid drugs and β-blockade, and requirement for mechanical ventilation and therapeutic plasma exchange combined with hemodialysis. The present study identified clinical features associated with mortality of thyroid storm using large-scale data. Physicians should pay special attention to older patients with thyrotoxicosis and coexisting central nervous system dysfunction. Future prospective studies are needed to clarify treatment options that could improve the survival outcomes of thyroid storm. PMID:26886648

  6. Modeling of the 22 July 2009 Storm

    NASA Technical Reports Server (NTRS)

    Fok, Mei-Ching; Buzulukova, Natalia

    2009-01-01

    The magnetic storm on 22 July 2009 is the greatest storm observed since the summer of 2008 when TWINS began its stereo imaging of the magnetosphere, On 22 July 2009, the Dst dropped to nearly -80 nT at 07:00 and 10:00 UT. During the main phase and at the peak of the storm, TWINS 1 and 2 were near apogee and moving from pre-dawn to post-dawn local time. The energetic neutral atom (ENA) Imagers on the 2 spacecraft captured the storm intensification and the formation of the partial ring current. The development of this storm has been simulated using the Comprehensive Ring Current Model (CRCM) to understand and interpret the observed signatures. The CRCM reproduced the double-dip in the Dst index and the simulated ENA flux intensities agree very well with the TWINS images. However, the peak of ion flux predicted by the model is always eastward of the observed maximum by TWINS. This discrepancy posts a challenge to reexamine the physical models employed in the CRCM.

  7. MAMS data for the Convection and Moisture Experiment (CAMEX)

    NASA Technical Reports Server (NTRS)

    Guillory, A. R.; Jedlovec, G. J.; Atkinson, R. J.

    1994-01-01

    During the fall of 1993, NASA sponsored a field program called the Convection And Moisture Experiment (CAMEX). The field effort focused on: convective storms in order to investigate their associated electrical properties, precipitation, and predictability, and atmospheric moisture studies. The data collected from the Multispectral Atmospheric Mapping Sensor (MAMS) onboard a NASA ER-2 aircraft which was deployed out of NASA/Wallops Flight Facility, Wallops Island, Virginia, from 11 Sep. through 7 Oct., 1993, is described.

  8. Spatial analysis of storm depths from an Arizona raingage network

    NASA Technical Reports Server (NTRS)

    Fennessey, N. M.; Eagleson, P. S.; Qinliang, W.; Rodriguez-Iturbe, I.

    1986-01-01

    Eight years of summer rainstorm observations are analyzed by a dense network of 93 raingages operated by the U.S. Department of Agriculture, Agricultural Research Service, in the 150 km Walnut Gulch experimental catchment near Tucson, Arizona. Storms are defined by the total depths collected at each raingage during the noon-to-noon period for which there was depth recorded at any of the gages. For each of the resulting 428 storm days, the gage depths are interpolated onto a dense grid and the resulting random field analyzed to obtain moments, isohyetal plots, spatial correlation function, variance function, and the spatial distribution of storm depth.

  9. Numerical Study of Urbanization Effect on 2012 Heavy Storm Precipitation in Beijing

    NASA Astrophysics Data System (ADS)

    Liu, Z.; Liu, S.; Xue, Y.; Oleson, K. W.

    2014-12-01

    In the past few decades, Great Beijing area has experienced rapid and widespread urbanization, which has significantly modified the land surface physical characteristics and affects urban regional climate.A single layer urban canopy module has been developed based on the Community Land Surface Model Urban Module (CLMU) with improvements: the energy balances on the five surface conditions are considered separately: building roof, sun side and shaded side wall, pervious and impervious land surface. A method to calculate sky view factor is developed based on the physically process while most urban models simply provide an empirical value. This method improves the solar and long wave radiation simulation on each surface; a new scheme for calculating the latent heat flux is applied on both wall and impervious land; the anthropogenic heat is considered in terms of industrial production, domestic wastes, vehicles and air condition. The urban effect on summer convective precipitation under the unstable atmospheric condition over Beijing was investigated by simulating a heavy storm event in July 21st 2012. In this storm, precipitation of averagely 164 mm was brought to Beijing within 6 hours, which is the record of past 60 years in the region. Numerical simulating experiment was set up by coupling Weather Research and Forecast (WRF)/SSiB3 model with the Modified CLMU (MCLMU). Several control cases without MCLMU were set up. The horizontal resolution in the inner domains was set to be 2 km. While all of the control results drastically underestimate the urban precipitation, the result of WRF/SSiB3/MCLMU is much closer to the observation. Sensitive experiments show that the existence of large area of impervious surfaces restrain the surface evaporation and latent heat flux in urban while the anthropogenic heat and enhanced sensible heat flux warm up the lower atmospheric layer and strengthen the vertical stratification instability, which is the key factor for storm while

  10. Convective heater

    DOEpatents

    Thorogood, Robert M.

    1983-01-01

    A convective heater for heating fluids such as a coal slurry is constructed of a tube circuit arrangement which obtains an optimum temperature distribution to give a relatively constant slurry film temperature. The heater is constructed to divide the heating gas flow into two equal paths and the tube circuit for the slurry is arranged to provide a mixed flow configuration whereby the slurry passes through the two heating gas paths in successive co-current, counter-current and co-current flow relative to the heating gas flow. This arrangement permits the utilization of minimum surface area for a given maximum film temperature of the slurry consistent with the prevention of coke formation.

  11. Convective heater

    DOEpatents

    Thorogood, Robert M.

    1986-01-01

    A convective heater for heating fluids such as a coal slurry is constructed of a tube circuit arrangement which obtains an optimum temperature distribution to give a relatively constant slurry film temperature. The heater is constructed to divide the heating gas flow into two equal paths and the tube circuit for the slurry is arranged to provide a mixed flow configuration whereby the slurry passes through the two heating gas paths in successive co-current, counter-current and co-current flow relative to the heating gas flow. This arrangement permits the utilization of minimum surface area for a given maximum film temperature of the slurry consistent with the prevention of coke formation.

  12. Convective heater

    DOEpatents

    Thorogood, R.M.

    1983-12-27

    A convective heater for heating fluids such as a coal slurry is constructed of a tube circuit arrangement which obtains an optimum temperature distribution to give a relatively constant slurry film temperature. The heater is constructed to divide the heating gas flow into two equal paths and the tube circuit for the slurry is arranged to provide a mixed flow configuration whereby the slurry passes through the two heating gas paths in successive co-current, counter-current and co-current flow relative to the heating gas flow. This arrangement permits the utilization of minimum surface area for a given maximum film temperature of the slurry consistent with the prevention of coke formation. 14 figs.

  13. Summer Skies

    ERIC Educational Resources Information Center

    Science Scope, 2005

    2005-01-01

    During the evening hours of the summer of 2005, there will be numerous opportunities to observe several of the brighter planets as they move along their respective orbits, overtaking and passing one another, performing a planetary dance with the choreography set to orbital speeds. With the exception of Mars, the visible planets will all be in the…

  14. Summer Opportunities.

    ERIC Educational Resources Information Center

    Winds of Change, 2002

    2002-01-01

    This directory describes 24 summer internships and cooperative education programs for college students, especially in the science, engineering, and technology fields. A few programs are specifically for American Indians, minority groups, or college-bound high school students. Program entries include a brief description, skills and background…

  15. Summer Programs.

    ERIC Educational Resources Information Center

    Toussaint, Isabella H.

    An intensive 6-week summer readiness program held in the Beaver Area School District, Beaver, Pennsylvania, developed linguistic facility among 15 preschool children. Daily activities included discussion, picture study, creative arts, field trips, developing experience charts, and other nonlanguage arts activities. A combined experiential,…

  16. Meteorological indicators of summer precipitation chemistry in central Pennsylvania

    NASA Astrophysics Data System (ADS)

    Dayan, Uri; Lamb, Dennis

    Daily precipitation chemistry data from nine consecutive summers (1993-2001) at a central Pennsylvania site were analyzed by objective and subjective methods and classified into key synoptic-scale circulation types. Significant differences in acidity and analyte concentrations were found among the seven storm types. The Convective type had the highest mean concentrations for all major ions compared to the Warm-Front (WF) type, which featured the lowest concentrations. The highest sulfate-to-nitrate ratio (2.36), assigned to the Warm-Sector (WS) type, indicates that acidity within air-masses transported to central Pennsylvania from the southwest is primarily in the form of H 2SO 4. About 20% of the overall acidity in precipitation during summer is neutralized by base cations. Both the Low-to-South and WF types have the lowest magnitudes of neutralization due to a lack of base cations of crustal origin. Both circulation systems are featured by an onshore flow from the Atlantic Ocean. Meteorological indicators for each weather type were developed based on values and geographical locations of anomalies of synoptic-scale variables, expressed as significant departures from their long-term means (as extracted from the Reanalysis NCEP/NCAR Model). The results suggest distinctive patterns for the regional position of the anomalies for the differing circulation systems. The two warm-weather types (High-to-South and Convective and WS) are featured by negative anomalies of sea-level pressure (SLP) and 850 hPa geopotential height (GPH) located northwest of the site and positive anomalies of the 850 hPa temperature to the east. Both are also associated with deep convection. The Cold-Front and Low-to-East types manifest an opposite symmetrical position of the anomalies, i.e., negative anomalies of SLP and 850 hPa GPH to the northeast and negative 850 hPa temperature anomalies northwest of the site. Both types are characterized by lower lifted indices, indicating weak atmospheric

  17. Kinetic energy budgets in areas of convection

    NASA Technical Reports Server (NTRS)

    Fuelberg, H. E.

    1979-01-01

    Synoptic scale budgets of kinetic energy are computed using 3 and 6 h data from three of NASA's Atmospheric Variability Experiments (AVE's). Numerous areas of intense convection occurred during the three experiments. Large kinetic energy variability, with periods as short as 6 h, is observed in budgets computed over each entire experiment area and over limited volumes that barely enclose the convection and move with it. Kinetic energy generation and transport processes in the smaller volumes are often a maximum when the enclosed storms are near peak intensity, but the nature of the various energy processes differs between storm cases and seems closely related to the synoptic conditions. A commonly observed energy budget for peak storm intensity indicates that generation of kinetic energy by cross-contour flow is the major energy source while dissipation to subgrid scales is the major sink. Synoptic scale vertical motion transports kinetic energy from lower to upper levels of the atmosphere while low-level horizontal flux convergence and upper-level horizontal divergence also occur. Spatial fields of the energy budget terms show that the storm environment is a major center of energy activity for the entire area.

  18. Structure of Highly Sheared Tropical Storm Chantal during CAMEX-4

    NASA Technical Reports Server (NTRS)

    Heymsfield, G. M.; Halverson, J.; Ritchie, E.; Simpson, Joanne; Molinari, J.; Tian, L.

    2006-01-01

    Tropical Storm Chantal during August 2001 was a storm that failed to intensify over the few days prior to making landfall on the Yucatan Peninsula. An observational study of Tropical Storm Chantal is presented using a diverse dataset including remote and in situ measurements from the NASA ER-2 and DC-8 and the NOAA WP-3D N42RF aircraft and satellite. The authors discuss the storm structure from the larger-scale environment down to the convective scale. Large vertical shear (850-200-hPa shear magnitude range 8-15 m/s) plays a very important role in preventing Chantal from intensifying. The storm had a poorly defined vortex that only extended up to 5-6-km altitude, and an adjacent intense convective region that comprised a mesoscale convective system (MCS). The entire low-level circulation center was in the rain-free western side of the storm, about 80 km to the west-southwest of the MCS. The MCS appears to have been primarily the result of intense convergence between large-scale, low-level easterly flow with embedded downdrafts, and the cyclonic vortex flow. The individual cells in the MCS such as cell 2 during the period of the observations were extremely intense, with reflectivity core diameters of 10 km and peak updrafts exceeding 20 m/s. Associated with this MCS were two broad subsidence (warm) regions, both of which had portions over the vortex. The first layer near 700 hPa was directly above the vortex and covered most of it. The second layer near 500 hPa was along the forward and right flanks of cell 2 and undercut the anvil divergence region above. There was not much resemblance of these subsidence layers to typical upper-level warm cores in hurricanes that are necessary to support strong surface winds and a low central pressure. The observations are compared to previous studies of weakly sheared storms and modeling studies of shear effects and intensification. The configuration of the convective updrafts, low-level circulation, and lack of vertical

  19. Effect of storm type on rainwater composition in southeastern North Carolina

    SciTech Connect

    Willey, J.D.; Bennett, R.I.; Williams, J.M. Denne, R.K.; Kornegay, C.R.; Perlotto, M.S.; Moore, B.M.

    1988-01-01

    Rainwater composition in Wilmington, NC, varies as a function of storm origin or type. During 1983-1987, the most acidic rain and highest sulfate and nitrate concentrations occurred in rain from local summer thunderstorms, followed by rain from continental frontal storms, with the least acidic rain coming from coastal storms. Seasonal variation was observed for rainwater pH (although not for sulfate or nitrate concentrations) from continental storms, with the most acidic rain in the summer. Thunderstorm nitrate concentrations were high enough to affect seasonal averages for nitrate concentration because thunderstorms are a warm-season type of rain. Coastal storm rainwater did not show seasonal changes; this type of rainwater is similar in pH, sulfate, and nitrate concentrations to rainwater in remote areas of the world. Sulfate from sea spray was a small percentage of the total sulfate except in coastal storm rainwater. Large annual differences in rainwater composition were observed.

  20. Global Deep Convection Models of Saturn's Atmospheric Features

    NASA Astrophysics Data System (ADS)

    Heimpel, Moritz; Cuff, Keith; Gastine, Thomas; Wicht, Johannes

    2016-04-01

    The Cassini mission, along with previous missions and ground-based observations, has revealed a rich variety of atmospheric phenomena and time variability on Saturn. Some examples of dynamical features are: zonal flows with multiple jet streams, turbulent tilted shear flows that seem to power the jets, the north polar hexagon, the south polar cyclone, large anticyclones in "storm alley", numerous convective storms (white spots) of various sizes, and the 2010/2011 great storm, which destroyed an array of vortices dubbed the "string of pearls". Here we use the anelastic dynamo code MagIC, in non-magnetic mode, to study rotating convection in a spherical shell. The thickness of the shell is set to approximate the depth of the low electrical conductivity deep atmosphere of Saturn, and the convective forcing is set to yield zonal flows of similar velocity (Rossby number) to those of Saturn. Internal heating and the outer entropy boundary conditions allow simple modelling of atmospheric layers with neutral stability or stable stratification. In these simulations we can identify several saturnian and jovian atmospheric features, with some variations. We find that large anticyclonic vortices tend to form in the first anticyclonic shear zones away from the equatorial jet. Cyclones form at the poles, and polar polygonal jet streams, comparable to Saturn's hexagon, may or may not form, depending on the model conditions. Strings of small scale vortical structures arise as convective plumes near boundaries of shear zones. They typically precede larger scale convective storms that spawn propagating shear flow disturbances and anticyclonic vortices, which tend to drift across anticyclonic shear zones, toward the equator (opposite the drift direction of Saturn's 2010/2011 storm). Our model results indicate that many identifiable dynamical atmospheric features seen on Jupiter and Saturn arise from deep convection, shaped by planetary rotation, underlying and interacting with stably

  1. Diurnal cycle of convection during the CAIPEEX 2011 experiment

    NASA Astrophysics Data System (ADS)

    Resmi, EA; Malap, Neelam; Kulkarni, Gayatri; Murugavel, P.; Nair, Sathy; Burger, Roelof; Prabha, Thara V.

    2016-10-01

    The diurnal cycle of convective storm events is investigated in the study with the help of C-band radar reflectivity data during the Cloud Aerosol Interaction and Precipitation Enhancement Experiment (CAIPEEX 2011) in combination with other ground-based observations. A threshold reflectivity of 25 dBZ is used to identify the initiation of storms. Observations from collocated sensors such as a microwave radiometer profiler, water vapor measurement from eddy covariance system, and wind lidar measurements are used to investigate the characteristic features and diurnal cycle of convectively initiated storms from 21st September to 5th November 2011. The maximum reflectivity follows a normal distribution with a mean value of 40 dBZ. The cloud depth over the domain varied between 5 and 15 km corresponding to a range of reflectivity of 30-50 dBZ values. In the diurnal cycle, double maximum in the precipitation flux is noted—one during the afternoon hours associated with the diurnal heating and the other in the nocturnal periods. The nocturnal precipitation maximum is attributed to initiation of several single-cell storms (of congestus type) with a duration that is larger than the storms initiated during the daytime. The convective available potential energy (CAPE) showed a diurnal variation and was directly linked with the surface level water vapor content. The high CAPE favored single storms with a reflectivity >40 dBZ and higher echo top heights. In the evening or late night hours, a nocturnal low-level jet present over the location together with the reduced stability above the cloud base favored enhancement of low-level moisture, CAPE, and further initiation of new convection. The study illustrated how collocated observations could be used to study storm initiation and associated thermodynamic features.

  2. Relationships between eastern Pacific tropical cyclones and convective rainfall in Baja California, Mexico

    NASA Astrophysics Data System (ADS)

    Farfan, L. M.; Cosio, M. A.

    2007-05-01

    The influence of tropical cyclones in rainfall patterns over the Baja California peninsula is examined. The impact of these systems, over the southern portion of the peninsula, is analyzed and the study period is limited to the summer of 2004. This is associated with the field phase of the North American Monsoon Experiment (NAME), which is intended to improve predictions of warm season precipitation over North America. We used the best-track dataset from the U.S. National Hurricane Center to classify, based on distance from the circulation center, systems that approached the peninsula at ranges of 400-, 800- and 1200-km. During the season of 2004, activity was below the long-term annual mean with nine systems developing between July and September. Four cases were selected for subsequent analysis: Tropical Storm Blas, Hurricane Frank, Hurricane Howard, and Hurricane Javier. Data from the upper-air station at La Paz were used to evaluate humidity changes during the storm approach and rain gauge reports provided information to determine the spatial distribution of the convective precipitation. Our analysis shows that, when compared with a base period of 15 years, 2004 resulted in below normal precipitation over the southern peninsula. In contrast, above normal conditions occurred in the central peninsula.

  3. Polar Summer

    NASA Technical Reports Server (NTRS)

    2005-01-01

    30 December 2005 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows eroding mesas of frozen carbon dioxide in the martian south polar residual cap. During the summer season, the scarps that bound each pit and mesa in the south polar region become dark as carbon dioxide sublimes away. The darkening might result from the roughening of the surfaces from which ice is subliming, or from the concentration of trace amounts of dust on these slopes, or both.

    Location near: 84.7oS, 48.2oW Image width: 3 km (1.9 mi) Illumination from: upper left Season: Southern Summer

  4. New insights on geomagnetic storms from observations and modeling

    SciTech Connect

    Jordanova, Vania K

    2009-01-01

    Understanding the response at Earth of the Sun's varying energy output and forecasting geomagnetic activity is of central interest to space science, since intense geomagnetic storms may cause severe damages on technological systems and affect communications. Episodes of southward (Bzstorms representative of each interplanetary condition with our kinetic ring current atmosphere interactions model (RAM), and investigate the mechanisms responsible for trapping particles and for causing their loss. We find that periods of increased magnetospheric convection coinciding with enhancements of plasma sheet density are needed for strong ring current buildup. During the HSS-driven storm the convection potential is highly variable and causes small sporadic injections into the ring current. The long period of enhanced convection during the CME-driven storm causes a continuous ring current injection penetrating to lower L shells and stronger ring current buildup.

  5. Intensification of Pacific storm track linked to Asian pollution.

    PubMed

    Zhang, Renyi; Li, Guohui; Fan, Jiwen; Wu, Dong L; Molina, Mario J

    2007-03-27

    Indirect radiative forcing of atmospheric aerosols by modification of cloud processes poses the largest uncertainty in climate prediction. We show here a trend of increasing deep convective clouds over the Pacific Ocean in winter from long-term satellite cloud measurements (1984-2005). Simulations with a cloud-resolving weather research and forecast model reveal that the increased deep convective clouds are reproduced when accounting for the aerosol effect from the Asian pollution outflow, which leads to large-scale enhanced convection and precipitation and hence an intensified storm track over the Pacific. We suggest that the wintertime Pacific is highly vulnerable to the aerosol-cloud interaction because of favorable cloud dynamical and microphysical conditions from the coupling between the Pacific storm track and Asian pollution outflow. The intensified Pacific storm track is climatically significant and represents possibly the first detected climate signal of the aerosol-cloud interaction associated with anthropogenic pollution. In addition to radiative forcing on climate, intensification of the Pacific storm track likely impacts the global general circulation due to its fundamental role in meridional heat transport and forcing of stationary waves.

  6. Multisensor Investigation of Deep Convection

    NASA Astrophysics Data System (ADS)

    Houze, R.; Yuan, J.; Barnes, H. C.; Brodzik, S. R.

    2012-12-01

    The array of sensors for studying cloud systems from space provides the opportunity to globally map the occurrence of various types of deep convective cloud systems more precisely than ever before. The revolutionary TRMM satellite has not only determined rainfall from space but also identified the structures of storms producing the rainfall and how the different types of convective structures relate to features of the global circulation. The multiple sensors of the A-Train constellation have added more capacity to globally map convective cloud system types. By simultaneously using Aqua's MODIS 11-micron brightness temperature sensor to map cloud-top size and coldness, Aqua's AMSR-E passive microwave to detect rainfall, and CloudSat's cloud radar observations to see the internal structure of the nonprecipitating anvil clouds extending laterally from the precipitating cores of mesoscale convective systems (MCSs), we have objectively identified and mapped different types of MCSs. This multisensor analysis has determined the degrees to which MCSs vary according to size, amount of anvil cloud, and whether or not they occur separately or in merged complexes. Using these multisensor-derived quantities, we have established the patterns in which tropical MCSs occur over land, ocean, or the maritime continent. Ongoing work is integrating more sensors and other innovative global datasets into the analysis of A-Train data to further knowledge of MCSs and their variability over the Earth. Global lightning data are being integrated with the A-Train data to better understand convective intensity in different types of MCSs. Environments of the MCSs identified by multisensor A-Train analysis are being further analyzed using AIRS temperature profiles and MODIS and CALIPSO aerosol fields to better document the influence of environmental properties on the different types of mesoscale system. The integration of aerosol loading into the global analysis of the patterns of occurrence of

  7. Regional analysis of convective systems during the West African monsoon

    NASA Astrophysics Data System (ADS)

    Guy, Bradley Nicholas

    The West African monsoon (WAM) occurs during the boreal summer and is responsible for a majority of precipitation in the northern portion of West Africa. A distinct shift of precipitation, often driven by large propagating mesoscale convective systems, is indicated from satellite observations. Excepting the coarser satellite observations, sparse data across the continent has prevented understanding of mesoscale variability of these important systems. The interaction between synoptic and mesoscale features appears to be an important part of the WAM system. Without an understanding of the mesoscale properties of precipitating systems, improved understanding of the feedback mechanism between spatial scales cannot be attained. Convective and microphysical characteristics of West African convective systems are explored using various observational data sets. Focus is directed toward meso -alpha and -beta scale convective systems to improve our understanding of characteristics at this spatial scale and contextualize their interaction with the larger-scale. Ground-based radar observations at three distinct geographical locations in West Africa along a common latitudinal band (Niamey, Niger [continental], Kawsara, Senegal [coastal], and Praia, Republic of Cape Verde [maritime]) are analyzed to determine convective system characteristics in each domain during a 29 day period in 2006. Ancillary datasets provided by the African Monsoon Multidisciplinary Analyses (AMMA) and NASA-AMMA (NAMMA) field campaigns are also used to place the radar observations in context. Results show that the total precipitation is dominated by propagating mesoscale convective systems. Convective characteristics vary according to environmental properties, such as vertical shear, CAPE, and the degree of synoptic forcing. Data are bifurcated based on the presence or absence of African easterly waves. In general, African easterly waves appear to enhance mesoscale convective system strength

  8. Meteorology, Macrophysics, Microphysics, Microwaves, and Mesoscale Modeling of Mediterranean Mountain Storms: The M8 Laboratory

    NASA Technical Reports Server (NTRS)

    Starr, David O. (Technical Monitor); Smith, Eric A.

    2002-01-01

    Comprehensive understanding of the microphysical nature of Mediterranean storms can be accomplished by a combination of in situ meteorological data analysis and radar-passive microwave data analysis, effectively integrated with numerical modeling studies at various scales, from synoptic scale down through the mesoscale, the cloud macrophysical scale, and ultimately the cloud microphysical scale. The microphysical properties of and their controls on severe storms are intrinsically related to meteorological processes under which storms have evolved, processes which eventually select and control the dominant microphysical properties themselves. This involves intense convective development, stratiform decay, orographic lifting, and sloped frontal lifting processes, as well as the associated vertical motions and thermodynamical instabilities governing physical processes that affect details of the size distributions and fall rates of the various types of hydrometeors found within the storm environment. Insofar as hazardous Mediterranean storms, highlighted in this study by three mountain storms producing damaging floods in northern Italy between 1992 and 2000, developing a comprehensive microphysical interpretation requires an understanding of the multiple phases of storm evolution and the heterogeneous nature of precipitation fields within a storm domain. This involves convective development, stratiform transition and decay, orographic lifting, and sloped frontal lifting processes. This also involves vertical motions and thermodynamical instabilities governing physical processes that determine details of the liquid/ice water contents, size disi:ributions, and fall rates of the various modes of hydrometeors found within hazardous storm environments.

  9. Dust storms: recent developments.

    PubMed

    Goudie, Andrew S

    2009-01-01

    Dust storms have a number of impacts upon the environment including radiative forcing, and biogeochemical cycling. They transport material over many thousands of kilometres. They also have a range of impacts on humans, not least on human health. In recent years the identification of source areas for dust storms has been an important area or research, with the Sahara (especially Bodélé) and western China being recognised as the strongest sources globally. Another major development has been the recognition of the degree to which dust storm activity has varied at a range of time scales, millennial, century, decadal, annual and seasonal.

  10. Hazards of geomagnetic storms

    USGS Publications Warehouse

    Herzog, D.C.

    1992-01-01

    Geomagnetic storms are large and sometimes rapid fluctuations in the Earth's magnetic field that are related to disturbances on the Sun's surface. Although it is not widely recognized, these transient magnetic disturbances can be a significant hazard to people and property. Many of us know that the intensity of the auroral lights increases during magnetic storms, but few people realize that these storms can also cause massive power outages, interrupt radio communications and satellite operations, increase corrosion in oil and gas pipelines, and lead to spuriously high rejection rates in the manufacture of sensitive electronic equipment. 

  11. Cloud formation, convection, and stratospheric dehydration

    NASA Astrophysics Data System (ADS)

    Schoeberl, Mark R.; Dessler, Andrew E.; Wang, Tao; Avery, Melody A.; Jensen, Eric J.

    2014-12-01

    Using the Modern-Era Retrospective Analysis for Research and Applications (MERRA) reanalysis winds, temperatures, and anvil cloud ice, we use our domain-filling, forward trajectory model combined with a new cloud module to show that convective transport of saturated air and ice to altitudes below the tropopause has a significant impact on stratospheric water vapor and upper tropospheric clouds. We find that including cloud microphysical processes (rather than assuming that parcel water vapor never exceeds saturation) increases the lower stratospheric average H2O by 10-20%. Our model-computed cloud fraction shows reasonably good agreement with tropical upper troposphere (TUT) cloud frequency observed by the Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) instrument in boreal winter with poorer agreement in summer. Our results suggest that over 40% of TUT cirrus is due to convection, and it is the saturated air from convection rather than injected cloud ice that primarily contributes to this increase. Convection can add up to 13% more water to the stratosphere. With just convective hydration (convection adds vapor up to saturation), the global lower stratospheric modeled water vapor is close to Microwave Limb Sounder observations. Adding convectively injected ice increases the modeled water vapor to ~8% over observations. Improving the representation of MERRA tropopause temperatures fields reduces stratospheric water vapor by ~4%.

  12. An Update to the Warm-Season Convective Wind Climatology of KSC/CCAFS

    NASA Technical Reports Server (NTRS)

    Lupo, Kevin

    2012-01-01

    Total of 1100 convective events in the 17-year warm-season climatology at KSC/CCAFS. July and August typically are the peak of convective events, May being the minimum. Warning and non-warning level convective winds are more likely to occur in the late afternoon (1900-2000Z). Southwesterly flow regimes and wind directions produce the strongest winds. Storms moving from southwesterly direction tend to produce more warning level winds than those moving from the northerly and easterly directions.

  13. Evaluating Changes in Extreme Weather During the North American Monsoon in the Southwest U.S. Using High Resolution, Convective-Permitting Regional Atmospheric Modeling

    NASA Astrophysics Data System (ADS)

    Castro, C. L.; Chang, H. I.; Luong, T. M.; Lahmers, T.; Jares, M.; Mazon, J.; Carrillo, C. M.; Adams, D. K.

    2015-12-01

    The North American monsoon (NAM) is the principal driver of summer severe weather in the Southwest U.S. Monsoon convection typically initiates during daytime over the mountains and may organize into mesoscale convective systems (MCSs). Most monsoon-related severe weather occurs in association with organized convection, including microbursts, dust storms, flash flooding and lightning. A convective resolving grid spacing (on the kilometer scale) model is required to explicitly represent the physical characteristics of organized convection, for example the presence of leading convective lines and trailing stratiform precipitation regions. Our objective is to analyze how monsoon severe weather is changing in relation to anthropogenic climate change. We first consider a dynamically downscaled reanalysis during a historical period 1948-2010. Individual severe weather event days, identified by favorable thermodynamic conditions, are then simulated for short-term, numerical weather prediction-type simulations of 30h at a convective-permitting scale. Changes in modeled severe weather events indicate increases in precipitation intensity in association with long-term increases in atmospheric instability and moisture, particularly with organized convection downwind of mountain ranges. However, because the frequency of synoptic transients is decreasing during the monsoon, organized convection is less frequent and convective precipitation tends to be more phased locked to terrain. These types of modeled changes also similarly appear in observed CPC precipitation, when the severe weather event days are selected using historical radiosonde data. Next, we apply the identical model simulation and analysis procedures to several dynamically downscaled CMIP3 and CMIP5 models for the period 1950-2100, to assess how monsoon severe weather may change in the future with respect to occurrence and intensity and if these changes correspond with what is already occurring in the historical

  14. Pilot Convective Weather Decision Making in En Route Airspace

    NASA Technical Reports Server (NTRS)

    Wu, Shu-Chieh; Gooding, Cary L.; Shelley, Alexandra E.; Duong, Constance G.; Johnson, Walter W.

    2012-01-01

    The present research investigates characteristics exhibited in pilot convective weather decision making in en route airspace. In a part-task study, pilots performed weather avoidance under various encounter scenarios. Results showed that the margins of safety that pilots maintain from storms are as fluid as deviation decisions themselves.

  15. Convective weather hazards in the Twin Cities Metropolitan Area, MN

    NASA Astrophysics Data System (ADS)

    Blumenfeld, Kenneth A.

    This dissertation investigates the frequency and intensity of severe convective storms, and their associated hazards, in the Twin Cities Metropolitan Area (TCMA), Minnesota. Using public severe weather reports databases and high spatial density rain gauge data, annual frequencies and return-periods are calculated for tornadoes, damaging winds, large hail, and flood-inducing rainfall. The hypothesis that severe thunderstorms and tornadoes are less likely in the central TCMA than in surrounding areas also is examined, and techniques for estimating 100-year rainfall amounts are developed and discussed. This research finds that: (i) storms capable of significant damage somewhere within the TCMA recur annually (sometimes multiple times per year), while storms virtually certain to cause such damage recur every 2-3 years; (ii) though severe weather reports data are not amenable to classical comparative statistical testing, careful treatment of them suggests all types and intensity categories of severe convective weather have been and should continue to be approximately as common in the central TCMA as in surrounding areas; and (iii) applications of Generalized Extreme Value (GEV) statistics and areal analyses of rainfall data lead to significantly larger (25-50%) estimates of 100-year rainfall amounts in the TCMA and parts of Minnesota than those currently published and used for precipitation design. The growth of the TCMA, the popular sentiment that downtown areas somehow deter severe storms and tornadoes, and the prior underestimation of extreme rainfall thresholds for precipitation design, all act to enhance local susceptibility to hazards from severe convective storms.

  16. Tropical Storm Faxai

    NASA Video Gallery

    NASA/JAXA's TRMM Satellite provided data of developing Tropical Storm Faxai to make this 3-D image that showed some towering thunderstorms in the area were reaching altitudes of up to 15.5km/~9.6 m...

  17. Tropical Storm Dolly Develops

    NASA Video Gallery

    This animation from NOAA's GOES-East satellite from Aug. 31-Sept. 2 shows the movement of a low pressure area from the western Caribbean Sea over the Yucatan Peninsula as it becomes Tropical Storm ...

  18. Powerful Midwest Storm System

    NASA Video Gallery

    This animation of imagery from NOAA’s GOES-13 satellite shows themovement of storm systems in the south central United States on May 20,2013. Warm, moist gulf air flowing across Texas, Oklahoma...

  19. Tropical Storm Don

    NASA Video Gallery

    GOES-13 data was compiled into an animation by the NASA GOES Project at NASA Goddard that shows the development of Tropical Storm Don in the southern Gulf of Mexico, west of Cuba. The animation run...

  20. Why do Tornados and Hail Storms Rest on Weekends?

    NASA Technical Reports Server (NTRS)

    Rosenfeld, Daniel; Bell, Thomas L.

    2010-01-01

    When anthropogenic aerosols over the eastern USA during summertime are at their weekly mid-week peak, tornado and hail storm activity there is also near its weekly maximum. The weekly cycle in storm activity is statistically significant and unlikely to be due to natural variability. The pattern of variability supports the hypothesis that air pollution aerosols invigorate deep convective clouds in a moist, unstable atmosphere, to the extent of inducing production of large hailstones and tornados. This is caused by the effect of aerosols on cloud-drop nucleation, making cloud drops smaller, delaying precipitation-forming processes and their evaporation, and hence affecting cloud dynamics.

  1. The 2008 Super Tuesday Tornado Outbreak: Overview of the Tornadoes and their Parent Storms

    NASA Technical Reports Server (NTRS)

    Knupp, Kevin R.; Coleman, Tim; Carey, Larry; Petersen, Walt

    2008-01-01

    The cold-season Tornado outbreak that occurred over the Southeast on 5-6 February 2008 was significant for the following reasons: about 84 tornadoes were documented over a 15 h period between late afternoon on 5 February and early morning on 6 February 2008; a wide variety of parent storms were associated with the tornadoes; a total of five EF-4 tornadoes occurred, with two forming over Alabama during the early morning hours prior to sunrise; there was a significant lull period between the initial convective and the early morning activity over Alabama 10 hours later; and, a wide spectrum of storm types, ranging from isolated supercell storms to QLCS bow echoes, accompanied the tornadoes. The goal of this paper is to provide a general description of the outbreak including the distribution of tornadoes and supercell storms over the region, a detailed map of the tornado tracks, time series of tornadoes and parent storms, and general characteristics of all parent tornado storms. The total number of major storms (duration greater than 3 h, at least three tornadoes produced) was seven. Several noteworthy storms are described: a long track (198 km long) tornado and its parent storm over Arkansas; a prolific supercell storm persisted for 7-8 hours and produced 16 tornadoes from north-central Mississippi to southern KY; and, bow echo storms (QLCS's) were simultaneous over KY and produced 16 tornadoes.

  2. The soundproof dynamical core for COSMO model: representation of convective flows.

    NASA Astrophysics Data System (ADS)

    Wójcik, Damian; Piotrowski, Zbigniew; Rosa, Bogdan; Ziemiański, Michał

    2014-05-01

    Research conducted at Polish Institute of Meteorology and Water Management, National Research Institute, in collaboration with Consortium for Small Scale Modeling (COSMO) are aimed at developing new conservative dynamical core for next generation operational weather prediction model. As the result, a new prototype model was developed with dynamical core based on anelastic set of equation and numerics adopted from the EULAG model. An employment of EULAG allowed to profit from its desirable conservative properties and numerical robustness confirmed in number of benchmark tests and widely documented in scientific literature. The hybrid model consists of EULAG dynamical core implemented into the software environment of the operational COSMO model and basic COSMO physical parameterizations involving turbulence, friction, radiation, moist processes and surface fluxes (COSMO-EULAG). The tool is capable to compute weather forecast in mountainous area for the horizontal resolution of 0.28 km and with slopes reaching 60 degrees of inclination. The presentation is focused on two current research topics. First, the model and especially its dynamics-physics coupling is examined within idealized framework for representation of convective flows. The study is based on two complementary convection benchmarks of Weisman and Klemp (Mon. Wea. Rev. 110:504, 1982) and Grabowski et al. (Q. J. R. Meteorol. Soc. 132:317, 2006). While the first experiment can be used to examine a life cycle of a single convective storm structure in COSMO-EULAG model, the second experiment allows to evaluate the model representation of statistical properties of daytime convective development over land, involving convection initiation as well as is transition into a deep phase. The study involves also the comparison of COSMO-EULAG results with results of standard compressible COSMO-Runge-Kutta model to test the suitability of the anelastic dynamical core for operational mesoscale high-resolution NWP. Next

  3. Observations of Convectively Coupled Kelvin Waves forced by Extratropical Wave Activity

    NASA Astrophysics Data System (ADS)

    Kiladis, G. N.; Biello, J. A.; Straub, K. H.

    2012-12-01

    It is well established by observations that deep tropical convection can in certain situations be forced by extratropical Rossby wave activity. Such interactions are a well-known feature of regions of upper level westerly flow, and in particular where westerlies and equatorward wave guiding by the basic state occur at low enough latitudes to interact with tropical and subtropical moisture sources. In these regions convection is commonly initiated ahead of upper level troughs, characteristic of forcing by quasi-geostrophic dynamics. However, recent observational evidence indicates that extratropical wave activity is also associated with equatorial convection even in regions where there is a "critical line" to Rossby wave propagation at upper levels, that is, where the zonal phase speed of the wave is equal to the zonal flow speed. A common manifestation of this type of interaction involves the initiation of convectively coupled Kelvin waves, as well as mixed Rossby-gravity (MRG) waves. These waves are responsible for a large portion of the convective variability within the ITCZ over the Indian, Pacific, and Atlantic sectors, as well as within the Amazon Basin of South America. For example, Kelvin waves originating within the western Pacific ITCZ are often triggered by Rossby wave activity propagating into the Australasian region from the South Indian Ocean extratropics. At other times, Kelvin waves are seen to originate along the eastern slope of the Andes. In the latter case the initial forcing is sometimes linked to a low-level "pressure surge," initiated by wave activity propagating equatorward from the South Pacific storm track. In yet other cases, such as over Africa, the forcing appears to be related to wave activity in the extratropics which is not necessarily propagating into low latitudes, but appears to "project" onto the Kelvin structure, in line with past theoretical and modeling studies. Observational evidence for extratropical forcing of Kelvin and MRG

  4. Climatological response of Indian low-latitude ionosphere to geomagnetic storms

    NASA Astrophysics Data System (ADS)

    Suresh, Sunanda; Dashora, N.

    2016-05-01

    A climatological response of low-latitude ionosphere to geomagnetic storms is presented using long-term global ionospheric maps data from June 1998 to June 2015 covering two solar cycles 23 and 24. The results are presented for daytime forenoon and afternoon sectors under minor, moderate, and major ionospheric storm categories based on minimum Dst index criterion. For the first time the effectiveness of storms is identified using monthly standard deviation as an indicator of the day to day variability in equatorial and low-latitude ionosphere. Thus, results on climatology are definitive and form a database that would be comparable to statistical results from any other longitude and time. Seasonal statistics for total storms, effective positive and negative storms, and amplitude of mean seasonal perturbation in total electron content are obtained. Total and effective storms are found to be higher in solar cycle 23 than in 24 and only a couple of effective storms occurred during low solar activity 2007-2009 that too in minor category. Afternoon sector is found to be favorable for occurrence of maximum number of effective positive storms. A latitudinal preference is found for a given storm to be effective in either time sectors. Equinoctial asymmetry in ionospheric response both in terms of occurrence and perturbation amplitude is found. September equinoxes are found to bear maximum total, effective positive and negative storms. Winters are found more prone to negative storms, whereas summers have recorded minimum number of either of storms and minimum perturbation amplitudes.

  5. METEOR - an artificial intelligence system for convective storm forecasting

    SciTech Connect

    Elio, R.; De haan, J.; Strong, G.S.

    1987-03-01

    An AI system called METEOR, which uses the meteorologist's heuristics, strategies, and statistical tools to forecast severe hailstorms in Alberta, is described, emphasizing the information and knowledge that METEOR uses to mimic the forecasting procedure of an expert meteorologist. METEOR is then discussed as an AI system, emphasizing the ways in which it is qualitatively different from algorithmic or statistical approaches to prediction. Some features of METEOR's design and the AI techniques for representing meteorological knowledge and for reasoning and inference are presented. Finally, some observations on designing and implementing intelligent consultants for meteorological applications are made. 7 references.

  6. Enhanced seasonality of storm track intensity under global warming

    NASA Astrophysics Data System (ADS)

    Lehmann, Jascha; Coumou, Dim; Frieler, Katja; Eliseev, Alexey; Levermann, Anders

    2013-04-01

    The seasonal cycle of extratropical storms is an important determinant of climatic conditions in regions along mid-latitude storm tracks. Severe storms during winter can cause severe damages over continents, whereas summer storms can actually bring relief to continents subject to prolonged hot and dry periods. It is thus of crucial importance to gain greater insight into the underlying mechanisms driving the seasonal cycle, as well as to assess future scenarios. Here we analyze the seasonality of extratropical storms in 20th and 21st century climates using CMIP5 model runs, based on different greenhouse gas emission scenarios. The synoptic-scale kinetic energy is derived for each individual month using a 2-6 day bandpass filter on daily wind fields. Intra-seasonal variations in storm track intensity are investigated using t-test analysis. The results indicate an enhanced seasonality in storm intensity under all future emission scenarios over both the Atlantic and Pacific region. Moreover, the amplification is significantly stronger for higher emissions. Differences in seasonality trends between the Northern and Southern Hemisphere as well as the underlying mechanisms will be discussed.

  7. A theoretical F region study of ion compositional and temperature variations in response to magnetospheric storm inputs

    NASA Technical Reports Server (NTRS)

    Sojka, J. J.; Schunk, R. W.

    1984-01-01

    The response of the high-latitude F region to magnetospheric storm inputs is modelled. During the 'storm', the spatial extent of the auroral oval, the intensity of the precipitating auroral electron energy flux, and the plasma convection pattern were varied with time. During the storm growth phase, the auroral oval expanded, the precipitating electron energy flux increased, and the magnetospheric convection pattern changed from a symmetric two-cell pattern with a 20 kV cross-tail potential to an asymmetric two-cell pattern with a total cross-tail potential of 90 kV. During the storm, there were significant changes in the ion temperature, ion composition, and molecular/atomic ion transition height. The storm time asymmetric convection pattern produced an ion temperature hot spot at the location of the dusk convection cell that contained significantly enhanced NO(+) densities. During the storm recovery phase, the decay of these densities closely followed the decrease in the plasma convection speed.

  8. Estimation of cold plasma outflow during geomagnetic storms

    NASA Astrophysics Data System (ADS)

    Haaland, S.; Eriksson, A.; André, M.; Maes, L.; Baddeley, L.; Barakat, A.; Chappell, R.; Eccles, V.; Johnsen, C.; Lybekk, B.; Li, K.; Pedersen, A.; Schunk, R.; Welling, D.

    2015-12-01

    Low-energy ions of ionospheric origin constitute a significant contributor to the magnetospheric plasma population. Measuring cold ions is difficult though. Observations have to be done at sufficiently high altitudes and typically in regions of space where spacecraft attain a positive charge due to solar illumination. Cold ions are therefore shielded from the satellite particle detectors. Furthermore, spacecraft can only cover key regions of ion outflow during segments of their orbit, so additional complications arise if continuous longtime observations, such as during a geomagnetic storm, are needed. In this paper we suggest a new approach, based on a combination of synoptic observations and a novel technique to estimate the flux and total outflow during the various phases of geomagnetic storms. Our results indicate large variations in both outflow rates and transport throughout the storm. Prior to the storm main phase, outflow rates are moderate, and the cold ions are mainly emanating from moderately sized polar cap regions. Throughout the main phase of the storm, outflow rates increase and the polar cap source regions expand. Furthermore, faster transport, resulting from enhanced convection, leads to a much larger supply of cold ions to the near-Earth region during geomagnetic storms.

  9. Estimation of cold plasma outflow during geomagnetic storms

    NASA Astrophysics Data System (ADS)

    Haaland, S.; Eriksson, A. I.; Andre, M.; Maes, L.; Baddeley, L. J.; Barakat, A. R.; Chappell, C. R.; Eccles, V.; Johnsen, C.; Lybekk, B.; Li, K.; Pedersen, A.; Schunk, R. W.; Welling, D. T.

    2015-12-01

    Low energy ions of ionospheric origin provide a significant contributon to the magnetospheric plasmapopulation. Measuring cold ions is difficult though. Observations have to be done at sufficiently high altitudes and typically in regions of space where spacecraft attain a positive charge due to solar illumination. Cold ions are therefore shielded from the satellite particle detectors. Furthermore, spacecraft can only cover key regions of ion outflow during segments of their orbit, so additional complications arise arise if continuous longtime observations such as the during a geomagnetic storms are needed. In this paper we suggest a new approach, based on a combination of synoptic observations and a novel technique to estimate the flux and total outflow during the various phases of geomagnetic storms. Our results indicate large variations in both outflow rates and transport throughout the storm. Prior to the storm main phase, outflow rates are moderate, and the cold ions are mainly emanating from moderately sized polar cap regions. Throughout the main phase of the storm, outflow rates increase and the polar cap source regions expand. Furthermore, faster transport, resulting from enhanced convection, leads to a much larger supply of cold ions to the near Earth region during gemagnetic storms.

  10. On extreme geomagnetic storms

    NASA Astrophysics Data System (ADS)

    Cid, Consuelo; Palacios, Judith; Saiz, Elena; Guerrero, Antonio; Cerrato, Yolanda

    2014-10-01

    Extreme geomagnetic storms are considered as one of the major natural hazards for technology-dependent society. Geomagnetic field disturbances can disrupt the operation of critical infrastructures relying on space-based assets, and can also result in terrestrial effects, such as the Quebec electrical disruption in 1989. Forecasting potential hazards is a matter of high priority, but considering large flares as the only criterion for early-warning systems has demonstrated to release a large amount of false alarms and misses. Moreover, the quantification of the severity of the geomagnetic disturbance at the terrestrial surface using indices as Dst cannot be considered as the best approach to give account of the damage in utilities. High temporal resolution local indices come out as a possible solution to this issue, as disturbances recorded at the terrestrial surface differ largely both in latitude and longitude. The recovery phase of extreme storms presents also some peculiar features which make it different from other less intense storms. This paper goes through all these issues related to extreme storms by analysing a few events, highlighting the March 1989 storm, related to the Quebec blackout, and the October 2003 event, when several transformers burnt out in South Africa.

  11. DE 2 observations of disturbances in the upper atmosphere during a geomagnetic storm

    NASA Technical Reports Server (NTRS)

    Miller, N. J.; Brace, L. H.; Spencer, N. W.; Carignan, G. R.

    1990-01-01

    Results are presented of physical interpretations of a sequence of in situ measurements taken in the midlatitude dusk sector during the geomagnetic storm of November 24, 1982 by instruments on board the DE-2 spacecraft in polar orbit. The results represent the first comparison of nearly simultaneous measurements, obtained at different seasons in a common local time sector, of storm disturbances in dc electric fields, zonal ion convection, zonal winds, gas composition and temperature, and electron density and temperature.

  12. Indian Summer

    SciTech Connect

    Galindo, E.

    1997-08-01

    This paper focuses on preserving and strengthening two resources culturally and socially important to the Shoshone-Bannock Indian Tribe on the Fort Hall Reservation in Idaho; their young people and the Pacific-Northwest Salmon. After learning that salmon were not returning in significant numbers to ancestral fishing waters at headwater spawning sites, tribal youth wanted to know why. As a result, the Indian Summer project was conceived to give Shoshone-Bannock High School students the opportunity to develop hands-on, workable solutions to improve future Indian fishing and help make the river healthy again. The project goals were to increase the number of fry introduced into the streams, teach the Shoshone-Bannock students how to use scientific methodologies, and get students, parents, community members, and Indian and non-Indian mentors excited about learning. The students chose an egg incubation experiment to help increase self-sustaining, natural production of steelhead trout, and formulated and carried out a three step plan to increase the hatch-rate of steelhead trout in Idaho waters. With the help of local companies, governmental agencies, scientists, and mentors students have been able to meet their project goals, and at the same time, have learned how to use scientific methods to solve real life problems, how to return what they have used to the water and land, and how to have fun and enjoy life while learning.

  13. Storm Warning Service

    NASA Technical Reports Server (NTRS)

    1993-01-01

    A Huntsville meteorologist of Baron Services, Inc. has formed a commercial weather advisory service. Weather information is based on data from Marshall Space Flight Center (MSFC) collected from antennas in Alabama and Tennessee. Bob Baron refines and enhances MSFC's real time display software. Computer data is changed to audio data for radio transmission, received by clients through an antenna and decoded by computer for display. Using his service, clients can monitor the approach of significant storms and schedule operations accordingly. Utilities and emergency management officials are able to plot a storm's path. A recent agreement with two other companies will promote continued development and marketing.

  14. Tropical Storm near Bermuda

    NASA Technical Reports Server (NTRS)

    1992-01-01

    This unnamed tropical storm near Bermuda (26.5N, 59.5W) was the result of a strong mid-latitude low pressure system that formed over the Gulf Stream near Cape Hatteras. It rapidly developed into a spiral gyre with internal wind speeds of up to 50 knots and whipped up the sea surface with swells of 15 to 20 feet creating dangerous boating conditions. These sub-hurricane storms are frequent occurances in this region during the fall, winter and spring.

  15. Evaluating and Understanding Parameterized Convective Processes and their Role in the Development of Mesoscale Precipitation Systems

    NASA Technical Reports Server (NTRS)

    Fritsch, J. Michael; Kain, John S.

    1997-01-01

    Research efforts during the second year have centered on improving the manner in which convective stabilization is achieved in the Penn State/NCAR mesoscale model MM5. Ways of improving this stabilization have been investigated by (1) refining the partitioning between the Kain-Fritsch convective parameterization scheme and the grid scale by introducing a form of moist convective adjustment; (2) using radar data to define locations of subgrid-scale convection during a dynamic initialization period; and (3) parameterizing deep-convective feedbacks as subgrid-scale sources and sinks of mass. These investigations were conducted by simulating a long-lived convectively-generated mesoscale vortex that occurred during 14-18 Jul. 1982 and the 10-11 Jun. 1985 squall line that occurred over the Kansas-Oklahoma region during the PRE-STORM experiment. The long-lived vortex tracked across the central Plains states and was responsible for multiple convective outbreaks during its lifetime.

  16. A portable CW/FM-CW Doppler radar for local investigation of severe storms

    SciTech Connect

    Unruh, W.P.; Wolf, M.A.; Bluestein, H.B.

    1988-01-01

    During the 1987 spring storm season we used a portable 1-W X-band CW Doppler radar to probe a tornado, a funnel cloud, and a wall cloud in Oklahoma and Texas. This same device was used during the spring storm season in 1988 to probe a wall cloud in Texas. The radar was battery powered and highly portable, and thus convenient to deploy from our chase vehicle. The device separated the receding and approaching Doppler velocities in real time and, while the radar was being used, it allowed convenient stereo data recording for later spectral analysis and operator monitoring of the Doppler signals in stereo headphones. This aural monitoring, coupled with the ease with which an operator can be trained to recognize the nature of the signals heard, made the radar very easy to operate reliably and significantly enhanced the quality of the data being recorded. At the end of the 1988 spring season, the radar was modified to include FM-CW ranging and processing. These modifications were based on a unique combination of video recording and FM chirp generation, which incorporated a video camera and recorder as an integral part of the radar. After modification, the radar retains its convenient portability and the operational advantage of being able to listen to the Doppler signals directly. The original mechanical design was unaffected by these additions. During the summer of 1988, this modified device was used at the Langmuir Laboratory at Socorro, New Mexico in an attempt to measure vertical convective flow in a thunderstorm. 2 refs., 2 figs.

  17. Numerical study of urbanization effect on a heavy storm event in Beijing

    NASA Astrophysics Data System (ADS)

    Liu, Z.

    2015-12-01

    In the past few decades, Great Beijing area has experienced rapid and widespread urbanization, which has substantially modified the land surface physical characteristics and affected urban regional weather and climate. A single layer urban canopy module has been developed based on the Community Land Surface Model Urban Module (CLMU) with several improvements: the energy balances on the five surface conditions (building roof, sun side and shaded side wall, pervious and impervious land surfaces) are considered separately. A method to calculate sky view factor is developed based on the physically process while most urban models simply provide an empirical value. This method improves the solar and long wave radiation simulation on each surface. The latent heat flux on both wall and impervious land is calculated; the anthropogenic heat is considered in terms of industrial production, domestic wastes, vehicles and air conditions. The urban effect on summer convective precipitation over Beijing was investigated by simulating a heavy storm event on July 21st 2012, when precipitation of averagely 164 mm was brought to Beijing within 6 hours, which is the heaviest during the past 60 years' record in the region. Numerical simulating experiment was set up by coupling Weather Research and Forecast (WRF)/SSiB3 model with the Modified CLMU (MCLMU). Several control cases without MCLMU were set up. The horizontal resolution in the inner domains was set to be 2 km. While all of the control results drastically underestimate the urban precipitation, the result of WRF/SSiB3/MCLMU is much closer to the observation. Sensitive experiments show that although large areas of impervious surfaces restrain the surface latent heat flux in urban, the anthropogenic heat and enhanced sensible heat flux warmed up the lower atmospheric layer then strengthen the vertical stratification instability, which is the key factor for heavy storm while moisture is sufficient.

  18. Tropical Storm Lee to Newfoundland

    NASA Video Gallery

    This video shows Tropical Storm Lee as it made landfall in Louisiana and Mississippi on September 4, 2011. This storm produced flooding and tornadoes to the southern states all the way to flooding ...

  19. Monitoring and automatic detection of the cold-ring patterns atop deep convective clouds using Meteosat data

    NASA Astrophysics Data System (ADS)

    Žibert, Mateja Iršič; Žibert, Janez

    2013-04-01

    This paper presents a newly established database of deep convective storms that exhibit a cold ring at their cloud top, as observed in enhanced infrared (IR) window satellite imagery. The database consists of cold-ring patterns as seen on the Meteosat data over the summer period between 2006 and 2010 for Slovenia and parts of Italy, Austria, Hungary and Croatia. It includes 139 cold rings at different stages, where typically large hail was reported on the ground and as such it serves as an important source of information for any quantitative analysis of the cold rings in this region. The typical characteristics of cold rings in this database are presented and discussed. It was found that the median of the difference between the minimum brightness temperature in the cold ring and the maximum brightness temperature in the central warm spot is 7.1 K, and that the median distance between such pair is 27 km. In addition, the paper presents in detail a new objective satellite-based method for cold-ring or cold-U/V pattern detection on storm tops in infrared imagery. This method uses a combination of infrared brightness temperature from the Meteosat Spinning Enhanced Visible and Infrared Imager (SEVIRI) and the tropopause temperatures from radiosonde measurements. The method was built and evaluated on the cold-ring patterns from the presented database.

  20. Recovery from major storms

    SciTech Connect

    Holeman, J.S.

    1980-01-01

    Public Service Company of Oklahoma's transmission and distribution system is in tornado alley, and it seems the number of tornados hitting some part of the system is increasing each year. In the past 30 years, Tulsa his been hit 7 times, and experienced 3 very wide and destructive tornado storm systems between 1971 and 1975.

  1. STORM INLET FILTRATION DEVICE

    EPA Science Inventory

    Five field tests were conducted to evaluate the effectiveness of the Storm and Groundwater Enhancement Systems (SAGES) device for removing contaminants from stormwater. The SAGES device is a three-stage filtering system that could be used as a best management practices (BMP) retr...

  2. California's Perfect Storm

    ERIC Educational Resources Information Center

    Bacon, David

    2010-01-01

    The United States today faces an economic crisis worse than any since the Great Depression of the 1930s. Nowhere is it sharper than in the nation's schools. Last year, California saw a perfect storm of protest in virtually every part of its education system. K-12 teachers built coalitions with parents and students to fight for their jobs and their…

  3. Weathering the storm

    SciTech Connect

    Burr, M.T.

    1993-02-01

    When Hurricane Andrew struck, thousands were displaced from their homes in Florida and Louisiana. Now, months after the winds ceased blowing, the storm is causing hardship once again. Insurance companies sustaining large losses in recent months from a number of natural disasters - including the hurricane - are now passing those losses on to their customers. Independent power companies are no exception.

  4. Stories from the Storm

    ERIC Educational Resources Information Center

    Smoczynski, Carol

    2007-01-01

    For four months, St. Paul's Episcopal School in the Lakeview neighborhood of New Orleans, Louisiana remained closed after Hurricane Katrina ravaged the entire city in August 2005. The storm left St. Paul's campus under nine feet of water for two weeks, destroying many buildings and the entire first floor of the campus. As the only remaining art…

  5. Convective Properties of A Landfalling Typhoon as Revealed by Lightning and Numerical Simulation

    NASA Astrophysics Data System (ADS)

    Zhang, W.; Xu, L.; Zhang, Y.

    2015-12-01

    Our knowledge about lightning activities in tropical cyclones (TCs) has been increasing during the last few years. Previous studies showed variation of spatial and temporal characteristics of TC lightning, and indicated the potential of using lightning data to predict changes of storm intensity and evolution of structure. Typhoon Molave (2009) exhibited strong convection and intense lightning during its landfall in China. In this work, lightning data from the World Wide Lightning Location Network (WWLLN), as well as data from S-band Radar were utilized to study the evolution of lightning during landfall and to investigate its relationship to TC convection. Simulation results from the Weather Research and Forecast (WRF) mesoscale model (version 3.2.1) were used to focus on the convective properties of Molave. The model reproduced well the strong convections in the inner core and rainbands, and featured the horizontal and vertical characteristics of convection evolution of the typhoon. Our results showed that lightning in the inner core outbreak prior to the maximum intensity of the storm and the bursts could be a good indicator of the imminent intensification of the storm. The large concentrations and increased distribution height of graupel and cloud water particles in the inner core, and the enhancement of updraft velocity were the main reasons for lightning outbreak in the inner core. The increased concentration of ice phase particles and the emergence of strong convection nuclear in the outer rainbands caused the peak frequency of TC lightning at the maximum intensity of the storm.

  6. Energy analysis of convectively induced wind perturbations

    NASA Technical Reports Server (NTRS)

    Fuelberg, Henry E.; Buechler, Dennis E.

    1989-01-01

    Budgets of divergent and rotational components of kinetic energy (KD and KR) are examined for four upper level wind speed maxima that develop during the fourth Atmospheric Variability Experiment (AVE IV) and the first AVE-Severe Environmental Storms and Mesoscale Experiment (AVE-SESAME I). A similar budget analysis is performed for a low-level jet stream during AVE-SESAME I. The energetics of the four upper level speed maxima is found to have several similarities. The dominant source of KD is cross-contour flow by the divergent wind, and KD provides a major source of KR via a conversion process. Conversion from available potential energy provides an additional source of KR in three of the cases. Horizontal maps reveal that the conversions involving KD are maximized in regions poleward of the convection. Low-level jet development during AVE-SESAME I appears to be assisted by convective activity to the west.

  7. Satellite remote sensing and cloud modeling of St. Anthony, Minnesota storm clouds and dew point depression

    NASA Technical Reports Server (NTRS)

    Hung, R. J.; Tsao, Y. D.

    1988-01-01

    Rawinsonde data and geosynchronous satellite imagery were used to investigate the life cycles of St. Anthony, Minnesota's severe convective storms. It is found that the fully developed storm clouds, with overshooting cloud tops penetrating above the tropopause, collapsed about three minutes before the touchdown of the tornadoes. Results indicate that the probability of producing an outbreak of tornadoes causing greater damage increases when there are higher values of potential energy storage per unit area for overshooting cloud tops penetrating the tropopause. It is also found that there is less chance for clouds with a lower moisture content to be outgrown as a storm cloud than clouds with a higher moisture content.

  8. The UAE Rainfall Enhancement Assessment Program: Implications of Thermodynamic Profiles on the Development of Precipitation in Convective Clouds over the Oman Mountains

    NASA Astrophysics Data System (ADS)

    Breed, D.; Bruintjes, R.; Jensen, T.; Salazar, V.; Fowler, T.

    2005-12-01

    During the winter and summer seasons of 2001 and 2002, data were collected to assess the efficacy of cloud seeding to enhance precipitation in the United Arab Emirates (UAE). The results of the feasibility study concluded: 1) that winter clouds in the UAE rarely produced conditions amenable to hygroscopic cloud seeding; 2) that summer convective clouds developed often enough, particularly over the Oman Mountains (e.g., the Hajar Mountains along the eastern UAE border and into Oman) to justify a randomized seeding experiment; 3) that collecting quantitative radar observations continues to be a complex but essential part of evaluating a cloud seeding experiment; 4) that successful flight operations would require solving several logistical issues; and 5) that several scientific questions would need to be studied in order to fully evaluate the efficacy and feasibility of hygroscopic cloud seeding, including cloud physical responses, radar-derived rainfall estimates as related to rainfall at the ground, and hydrological impacts. Based on these results, the UAE program proceeded through the design and implemention of a randomized hygroscopic cloud seeding experiment during the summer seasons to statistically quantify the potential for cloud seeding to enhance rainfall, specifically over the UAE and Oman Mountains, while collecting concurrent and separate physical measurements to support the statistical results and provide substantiation for the physical hypothesis. The randomized seeding experiment was carried out over the summers of 2003 and 2004, and a total of 134 cases were treated over the two summer seasons, of which 96 met the analysis criteria established in the experimental design of the program. The statistical evaluation of these cases yielded largely inconclusive results. Evidence will show that the thermodynamic profile had a large influence on storm characteristics and on precipitation development. This in turn provided a confounding factor in the conduct

  9. Dynamics Of Saturn'S Mid-scale Storms In The Cassini Era.

    NASA Astrophysics Data System (ADS)

    Del Rio Gaztelurrutia, Teresa; Hueso, R.; Sánchez-Lavega, A.

    2010-10-01

    Convective storms, similar to those in Earth, but of much larger scale, develop often in Saturn's atmosphere. During the Voyagers’ flybys of Saturn in 1981 mid-scale storms, with an horizontal extension of the order of 1000-3000 km were observed to occur mainly in a narrow tropical-latitude band in the Northern hemisphere at latitudes 38-40 deg North. Contrasting with the Voyagers’ era, since the starting of the Cassini mission in 2004, a similar mid-scale convective activity has concentrated in the so-called "storm alley", a narrow band at a symmetric Southern latitude of 38 deg.. In this work, we characterize this storm activity using available visual information provided by Cassini ISS cameras and the continuous survey from the Earth by the International Outer Planets Watch (IOPW) and its online database PVOL (Hueso et al., Planetary and Space Science, 2010). We study the frequency of appearance of storms with sizes above 2000 km, their characteristic size and life-time, as well as their interaction with surrounding dynamical features. In particular we examine the possibility that storms might provide a mechanism of injection of energy into Saturn's jets, the influence of storms in the generation of atmospheric vortices, and the analogies and differences of Voyagers’ and present day jet structure at the relevant latitudes. Acknowledgments: This work has been funded by the Spanish MICIIN AYA2009-10701 with FEDER support and Grupos Gobierno Vasco IT-464

  10. Energy and Mass Transport of Magnetospheric Plasmas during the November 2003 Magnetic Storm

    NASA Technical Reports Server (NTRS)

    Fok, Mei-Chging; Moore, Thomas

    2008-01-01

    Intensive energy and mass transport from the solar wind across the magnetosphere boundary is a trigger of magnetic storms. The storm on 20-21 November 2003 was elicited by a high-speed solar wind and strong southward component of interplanetary magnetic field. This storm attained a minimum Dst of -422 nT. During the storm, some of the solar wind particles enter the magnetosphere and eventually become part of the ring current. At the same time, the fierce solar wind powers strong outflow of H+ and O+ from the ionosphere, as well as from the plasmasphere. We examine the contribution of plasmas from the solar wind, ionosphere and plasmasphere to the storm-time ring current. Our simulation shows, for this particular storm, ionospheric O+ and solar wind ions are the major sources of the ring current particles. The polar wind and plasmaspheric H+ have only minor impacts. In the storm main phase, the strong penetration of solar wind electric field pushes ions from the geosynchronous orbit to L shells of 2 and below. Ring current is greatly intensified during the earthward transport and produces a large magnetic depression in the surface field. When the convection subsides, the deep penetrating ions experience strong charge exchange loss, causing rapid decay of the ring current and fast initial storm recovery. Our simulation reproduces very well the storm development indicated by the Dst index.

  11. Decadal change in the boreal summer intraseasonal oscillation

    NASA Astrophysics Data System (ADS)

    Yamaura, Tsuyoshi; Kajikawa, Yoshiyuki

    2016-06-01

    A decadal change in activity of the boreal summer intraseasonal oscillation (BSISO) was identified at a broad scale. The change was more prominent during August-October in the boreal summer. The BSISO activity during 1999-2008 (P2) was significantly greater than that during 1984-1998 (P1). Compared to P1, convection in the BSISO was enhanced and the phase speed of northward-propagating convection was reduced in P2. Under background conditions, warm sea surface temperature (SST) anomalies in P2 were apparent over the tropical Indian Ocean and the western tropical Pacific. The former supplied favorable conditions for the active convection of the BSISO, whereas the latter led to a strengthened Walker circulation through enhanced convection. This induced descending anomalies over the tropical Indian Ocean. Thermal convection tends to be suppressed by descending anomalies, whereas once an active BSISO signal enters the Indian Ocean, convection is enhanced through convective instability by positive SST anomalies. After P2, the BSISO activity was weakened during 2009-2014 (P3). Compared to P2, convective activity in the BSISO tended to be inactive over the southern tropical Indian Ocean in P3. The phase speed of the northward-propagating convection was accelerated. Under background conditions during P3, warmer SST anomalies over the maritime continent enhance convection, which strengthened the local Hadley circulation between the western tropical Pacific and the southern tropical Indian Ocean. Hence, the convection in the BSISO over the southern tropical Indian Ocean was suppressed. The decadal change in BSISO activity correlates with the variability in seasonal mean SST over the tropical Asian monsoon region, which suggests that it is possible to predict the decadal change.

  12. After the Storm

    ERIC Educational Resources Information Center

    Noble, Beth

    1971-01-01

    Describes curricular changes and experimental interdisciplinary approaches in teaching foreign languages at Grinnell College, Grinnell, Iowa. Paper read at the 1971 ADFL Summer Seminar for Chairmen, June 21-25, at Middlebury College, Middlebury, Vermont. (DS)

  13. The source of O+ in the storm time ring current

    NASA Astrophysics Data System (ADS)

    Kistler, L. M.; Mouikis, C. G.; Spence, H. E.; Menz, A. M.; Skoug, R. M.; Funsten, H. O.; Larsen, B. A.; Mitchell, D. G.; Gkioulidou, M.; Wygant, J. R.; Lanzerotti, L. J.

    2016-06-01

    A stretched and compressed geomagnetic field occurred during the main phase of a geomagnetic storm on 1 June 2013. During the storm the Van Allen Probes spacecraft made measurements of the plasma sheet boundary layer and observed large fluxes of O+ ions streaming up the field line from the nightside auroral region. Prior to the storm main phase there was an increase in the hot (>1 keV) and more isotropic O+ ions in the plasma sheet. In the spacecraft inbound pass through the ring current region during the storm main phase, the H+ and O+ ions were significantly enhanced. We show that this enhanced inner magnetosphere ring current population is due to the inward adiabatic convection of the plasma sheet ion population. The energy range of the O+ ion plasma sheet that impacts the ring current most is found to be from ~5 to 60 keV. This is in the energy range of the hot population that increased prior to the start of the storm main phase, and the ion fluxes in this energy range only increase slightly during the extended outflow time interval. Thus, the auroral outflow does not have a significant impact on the ring current during the main phase. The auroral outflow is transported to the inner magnetosphere but does not reach high enough energies to affect the energy density. We conclude that the more energetic O+ that entered the plasma sheet prior to the main phase and that dominates the ring current is likely from the cusp.

  14. The relationship of storm severity to directionally resolved radio emissions

    NASA Astrophysics Data System (ADS)

    Johnson, R. L.

    1986-04-01

    The objective was to provide continuous observation of atmospheric electrical activity occurring in association with tropical storms in the Gulf of Mexico. The observations were to include the location of all detected intracloud and cloud-to-ground lightning activity occurring in the storm. To provide synoptic scale coverage, a phase linear interferometer high frequency direction finder (HFDF) system was constructed and developed at Marshall Space Flight Center (MSFC). This was used in concert with the existing HFDF interferometer at the southwest research institute to provide lightning location data through triangulation. Atmospheric electrical events were synchronized through the use of satellite receivers at each site. The intent of the data analysis was to correlate the location of electrical centers of activity with radar and satellite imagry to identify areas of intense convection within the tropical storm system. Analysis of the hurricane Alicia data indicate a center of atmospheric electrical activity associated with the vortex of the storm. The center appears to rotate from the Northern side of the vortex to the Southern side during the period of observation. An analysis of the atmospheric electrical burst rates associated with hurrican Alicia indicates that the electrical activity appears to maximize at the time of greatest storm intensity, i.e., maximum winds and lowest central pressure.

  15. Wind Shear May Produce Long-Lived Storms and Squall Lines on Titan

    NASA Astrophysics Data System (ADS)

    Rafkin, Scot C. R.; Barth, Erika

    2015-11-01

    The impact of CAPE and wind shear on storms in a Titan-like environment are explored through numerical simulation. Numerical modeling indicates that both large-scale shear and CAPE environment control the dynamics of the clouds. This response to the large-scale environment is analogous to the behavior of deep convective clouds on Earth. The balance between shear and CAPE, as expressed through the bulk Richardson Number (NR), is a good indicator of the response of a storm to its environment. Large NR results in short-lived single cell storms (Figure 1). As shear increases for a given CAPE, and NR decreases, the storms transition to a multicellular regime. Multicellular storms are longer-lived and are characterized by a downdraft generated cold pool that interacts with the background shear vorticity to initiate cells along the leading edge of the storm gust front (Figure 2). Very long-lived storms (>24 hours) propagating for 1000 km or more might be possible. The most intense multicellular systems simulated in this study behave similar to terrestrial squall lines, and very long-lived storms (>24 hours) propagating for 1000 km or more might be possible. Cloud outbursts and linear cloud features observed from ground and Cassini may be the result of these organized storm systems. Varying amounts of shear in the Titan environment might explain the variety of convective cloud expressions identified in Cassini orbiter and ground-based observations. The resulting distribution and magnitude of precipitation as well as surface winds associated with storms have implications on the formation of fluvial and aeolian features, including dunes, and on the exchange of methane with the surface and lakes.

  16. Historic and Future Ice Storms

    NASA Astrophysics Data System (ADS)

    Klima, K.; Morgan, M. G.

    2014-12-01

    Ice storm losses from business interruption as well as transportation and health damages can range into billions of dollars. For instance, the December 2008 New England and Upstate New York ice storm caused four deaths and monetary damages between 2.5 and 3.7 billion, and the 2008 Chinese winter storms resulted in over 130 deaths and over 20 billion in damages. Informal discussions with ice storm experts indicate that due to competing temperature and precipitation effects as well as local topographic effects, it is unclear how exactly climate change will affect ice storms. Here we ask how incident frequencies might change in a future climate at four weather stations prone to ice storms. Using historical atmospheric soundings, we conduct a thought experiment where we perturb the temperatures as might be expected in a future climate. We then discuss changes in monthly frequency of ice storms.

  17. Storm water pollution prevention plans

    SciTech Connect

    Rossmiller, R.L. )

    1993-03-01

    National Pollutant Discharge Elimination System (NPDES) general permit applications for industrial storm water discharge were to have been filed by October 1992. The Environmental Protection Agency (EPA) and state agencies are now issuing permits based on these applications. One compliance aspect of the permits is the Storm Water Pollution Prevention Plan (SWP3). The plan must identify the facility's potential sources of storm water pollution and develop and implement best management practices (BMPs) to reduce pollutants in storm water runoff. The objectives of the NPDES storm water program are to eliminate illegal dumping and illicit connections, and to reduce pollutants in industrial storm water discharge. These regulations require industry to develop detailed facility site maps, and describe the types, amounts and locations of potential pollutants. Based on this information, industry can develop and implement best management practices to reduce pollutants in storm water runoff.

  18. Extreme Helicity and Intense Convective Towers in Hurricane Bonnie

    NASA Technical Reports Server (NTRS)

    Molinari, John; Vollaro, David

    2008-01-01

    Helicity was calculated in Hurricane Bonnie (1998) using tropospheric-deep dropsonde soundings from the NASA Convection and Moisture Experiment. Large helicity existed downshear of the storm center with respect to the ambient vertical wind shear. It was associated with veering, semicircular hodographs created by strong, vortex-scale, radial-vertical flow induced by the shear. The most extreme values of helicity, among the largest ever reported in the literature, occurred in the vicinity of deep convective cells in the downshear-left quadrant. These cells reached as high as 17.5 km and displayed the temporal and spatial scales of supercells. Convective available potential energy (CAPE) averaged 861 J/kg downshear, but only about one-third as large upshear. The soundings nearest the deep cells were evaluated using two empirical supercell parameters that make use of CAPE, helicity, and/or shear. These parameters supported the possible existence of supercells as a consequence of the exceptional helicity combined with moderate but sufficient CAPE. Ambient vertical wind shear exceeded 12 m/s for 30 h, yet the hurricane maintained 50 m/s maximum winds. It is hypothesized that the long-lived convective cells enabled the storm to resist the negative impact of the shear. Supercells in large-helicity, curved-hodograph environments appear to provide a useful conceptual model for intense convection in the hurricane core. Helicity calculations might also give some insight into the behavior of vortical hot towers, which share some characteristics with supercells.

  19. Oxidant enhancement in martian dust devils and storms: storm electric fields and electron dissociative attachment.

    PubMed

    Delory, Gregory T; Farrell, William M; Atreya, Sushil K; Renno, Nilton O; Wong, Ah-San; Cummer, Steven A; Sentman, Davis D; Marshall, John R; Rafkin, Scot C R; Catling, David C

    2006-06-01

    Laboratory studies, numerical simulations, and desert field tests indicate that aeolian dust transport can generate atmospheric electricity via contact electrification or "triboelectricity." In convective structures such as dust devils and dust storms, grain stratification leads to macroscopic charge separations and gives rise to an overall electric dipole moment in the aeolian feature, similar in nature to the dipolar electric field generated in terrestrial thunderstorms. Previous numerical simulations indicate that these storm electric fields on Mars can approach the ambient breakdown field strength of approximately 25 kV/m. In terrestrial dust phenomena, potentials ranging from approximately 20 to 160 kV/m have been directly measured. The large electrostatic fields predicted in martian dust devils and storms can energize electrons in the low pressure martian atmosphere to values exceeding the electron dissociative attachment energy of both CO2 and H2O, which results in the formation of the new chemical products CO/O- and OH/H-, respectively. Using a collisional plasma physics model, we present calculations of the CO/O- and OH/H- reaction and production rates. We demonstrate that these rates vary geometrically with the ambient electric field, with substantial production of dissociative products when fields approach the breakdown value of approximately 25 kV/m. The dissociation of H2O into OH/H- provides a key ingredient for the generation of oxidants; thus electrically charged dust may significantly impact the habitability of Mars. PMID:16805701

  20. Extreme Geomagnetic Storms - 1868 - 2010

    NASA Astrophysics Data System (ADS)

    Vennerstrom, S.; Lefevre, L.; Dumbović, M.; Crosby, N.; Malandraki, O.; Patsou, I.; Clette, F.; Veronig, A.; Vršnak, B.; Leer, K.; Moretto, T.

    2016-05-01

    We present the first large statistical study of extreme geomagnetic storms based on historical data from the time period 1868 - 2010. This article is the first of two companion papers. Here we describe how the storms were selected and focus on their near-Earth characteristics. The second article presents our investigation of the corresponding solar events and their characteristics. The storms were selected based on their intensity in the aa index, which constitutes the longest existing continuous series of geomagnetic activity. They are analyzed statistically in the context of more well-known geomagnetic indices, such as the Kp and Dcx/Dst index. This reveals that neither Kp nor Dcx/Dst provide a comprehensive geomagnetic measure of the extreme storms. We rank the storms by including long series of single magnetic observatory data. The top storms on the rank list are the New York Railroad storm occurring in May 1921 and the Quebec storm from March 1989. We identify key characteristics of the storms by combining several different available data sources, lists of storm sudden commencements (SSCs) signifying occurrence of interplanetary shocks, solar wind in-situ measurements, neutron monitor data, and associated identifications of Forbush decreases as well as satellite measurements of energetic proton fluxes in the near-Earth space environment. From this we find, among other results, that the extreme storms are very strongly correlated with the occurrence of interplanetary shocks (91 - 100 %), Forbush decreases (100 %), and energetic solar proton events (70 %). A quantitative comparison of these associations relative to less intense storms is also presented. Most notably, we find that most often the extreme storms are characterized by a complexity that is associated with multiple, often interacting, solar wind disturbances and that they frequently occur when the geomagnetic activity is already elevated. We also investigate the semiannual variation in storm occurrence

  1. Severe storm electricity

    NASA Technical Reports Server (NTRS)

    Rust, W. D.; Macgorman, D. R.

    1985-01-01

    During FY-85, Researchers conducted a field program and analyzed data. The field program incorporated coordinated measurements made with a NASA U2. Results include the following: (1) ground truth measurements of lightning for comparison with those obtained by the U2; (2) analysis of dual-Doppler radar and dual-VHF lightning mapping data from a supercell storm; (3) analysis of synoptic conditions during three simultaneous storm systems on 13 May 1983 when unusually large numbers of positive cloud-to-ground (+CG) flashes occurred; (4) analysis of extremely low frequency (ELF) wave forms; and (5) an assessment of a cloud -ground strike location system using a combination of mobile laboratory and fixed-base TV video data.

  2. Severe storm electricity

    NASA Technical Reports Server (NTRS)

    Arnold, R. T.; Rust, W. D.

    1984-01-01

    Successful ground truth support of U-2 overflights was been accomplished. Data have been reduced for 4 June 1984 and some of the results have been integrated into some of MSFC's efforts. Staccato lightning (multiply branched, single stroke flash with no continuing current) is prevalent within the rainfree region around the main storm updraft and this is believed to be important, i.e., staccato flashes might be an important indicator of severe storm electrification. Results from data analysis from two stations appear to indicate that charge center heights can be estimated from a combination of intercept data with data from the fixed laboratory at NSSL. An excellent data base has been provided for determining the sight errors and efficiency of NSSL's LLP system. Cloud structures, observable in a low radar reflectivity region and on a scale smaller than is currently resolved by radar, which appear to be related to electrical activity are studied.

  3. Dust Storm, Aral Sea

    NASA Technical Reports Server (NTRS)

    2002-01-01

    The Aral Sea has shrunk to less than half its size since 1985. The Aral Sea receives little water (sometimes no water) from the two major rivers that empty into it-the Syr Darya and Amu Darya. Instead, the river water is diverted to support irrigation for the region's extensive cotton fields. Recently, water scarcity has increased due to a prolonged drought in Central Asia. As the Aral Sea recedes, its former sea bed is exposed. The Aral's sea bed is composed of fine sediments-including fertilizers and other agricultural chemicals-that are easily picked up by the region's strong winds, creating thick dust storms. The International Space Station crew observed and recorded a large dust storm blowing eastward from the Aral Sea in late June 2001. This image illustrates the strong coupling between human activities (water diversions and irrigation), and rapidly changing land, sea and atmospheric processes-the winds blow across the

  4. TRMM precipitation analysis of extreme storms in South America: Bias and climatological contribution

    NASA Astrophysics Data System (ADS)

    Rasmussen, K. L.; Houze, R.; Zuluaga, M. D.; Choi, S. L.; Chaplin, M.

    2013-12-01

    The TRMM (Tropical Rainfall Measuring Mission) satellite was designed both to measure spatial and temporal variation of tropical rainfall around the globe and to understand the factors controlling the precipitation. TRMM observations have led to the realization that storms just east of the Andes in southeastern South America are among the most intense deep convection in the world. For a complete perspective of the impact of intense precipitation systems on the hydrologic cycle in South America, it is necessary to assess the contribution from various forms of extreme storms to the climatological rainfall. However, recent studies have suggested that the TRMM Precipitation Radar (PR) algorithm significantly underestimates surface rainfall in deep convection over land. Prior to investigating the climatological behavior, this research first investigates the range of the rain bias in storms containing four different types of extreme radar echoes: deep convective cores, deep and wide convective cores, wide convective cores, and broad stratiform regions over South America. The TRMM PR algorithm exhibits bias in all four extreme echo types considered here when the algorithm rates are compared to a range of conventional Z-R relations. Storms with deep convective cores, defined as high reflectivity echo volumes that extend above 10 km in altitude, show the greatest underestimation, and the bias is unrelated to their echo top height. The bias in wide convective cores, defined as high reflectivity echo volumes that extend horizontally over 1,000 km2, relates to the echo top, indicating that storms with significant mixed phase and ice hydrometeors are similarly affected by assumptions in the TRMM PR algorithm. The subtropical region tends to have more intense precipitating systems than the tropics, but the relationship between the TRMM PR rain bias and storm type is the same regardless of the climatological regime. The most extreme storms are typically not collocated with

  5. Development in the STORM.

    PubMed

    Kamiyama, Daichi; Huang, Bo

    2012-12-11

    The recent invention of superresolution microscopy has brought up much excitement in the biological research community. Here, we focus on stochastic optical reconstruction microscopy/photoactivated localization microscopy (STORM/PALM) to discuss the challenges in applying superresolution microscopy to the study of developmental biology, including tissue imaging, sample preparation artifacts, and image interpretation. We also summarize new opportunities that superresolution microscopy could bring to the field of developmental biology. PMID:23237944

  6. Ice Storm Supercomputer

    SciTech Connect

    2009-01-01

    "A new Idaho National Laboratory supercomputer is helping scientists create more realistic simulations of nuclear fuel. Dubbed 'Ice Storm,' this 2048-processor machine allows researchers to model and predict the complex physics behind nuclear reactor behavior. And with a new visualization lab, the team can see the results of its simulations on the big screen." For more information about INL research, visit http://www.facebook.com/idahonationallaboratory.

  7. Ice Storm Supercomputer

    ScienceCinema

    None

    2016-07-12

    "A new Idaho National Laboratory supercomputer is helping scientists create more realistic simulations of nuclear fuel. Dubbed 'Ice Storm,' this 2048-processor machine allows researchers to model and predict the complex physics behind nuclear reactor behavior. And with a new visualization lab, the team can see the results of its simulations on the big screen." For more information about INL research, visit http://www.facebook.com/idahonationallaboratory.

  8. Dust storm, northern Mexico

    NASA Technical Reports Server (NTRS)

    1983-01-01

    This large dust storm along the left side of the photo, covers a large portion of the state of Coahuila, Mexico (27.5N, 102.0E). The look angle of this oblique photo is from the south to the north. In the foreground is the Sierra Madre Oriental in the states Coahuila and Nuevo Leon with the Rio Grande River, Amistad Reservoir and Texas in the background.

  9. Tropical storms: representation and diagnosis in climate models and the impacts of climate change

    NASA Astrophysics Data System (ADS)

    McDonald, R. E.; Bleaken, D. G.; Cresswell, D. R.; Pope, V. D.; Senior, C. A.

    2005-07-01

    Tropical storms are located and tracked in an experiment in which a high-resolution atmosphere only model is forced with observed sea surface temperatures (SSTs) and sea ice. The structure, geographic distribution and seasonal variability of the model tropical storms show some similarities with observations. The simulation of tropical storms is better in this high-resolution experiment than in a parallel standard resolution experiment. In an anomaly experiment, sea ice, SSTs and greenhouse-gas forcing are changed to mimic the changes that occur in a coupled model as greenhouse-gases are increased. There are more tropical storms in this experiment than in the control experiment in the Northeast Pacific and Indian Ocean basins and fewer in the North Atlantic, Northwest Pacific and Southwest Pacific region. The changes in the North Atlantic and Northwest Pacific can be linked to El Niño-like behaviour. A comparison of the tracking results with two empirically derived tropical storm genesis parameters is carried out. The tracking technique and a convective genesis parameter give similar results, both in the global distribution and in the changes in the individual basins. The convective genesis parameter is also applied to parallel coupled model experiments that have a lower horizontal resolution. The changes in the global distribution of tropical storms in the coupled model experiments are consistent with the changes seen at higher resolution. This indicates that the convective genesis parameter may still provide useful information about tropical storm changes in experiments carried out with models that cannot resolve tropical storms.

  10. Defining Coastal Storm and Quantifying Storms Applying Coastal Storm Impulse Parameter

    NASA Astrophysics Data System (ADS)

    Mahmoudpour, Nader

    2014-05-01

    What defines a storm condition and what would initiate a "storm" has not been uniquely defined among scientists and engineers. Parameters that have been used to define a storm condition can be mentioned as wind speed, beach erosion and storm hydrodynamics parameters such as wave height and water levels. Some of the parameters are storm consequential such as beach erosion and some are not directly related to the storm hydrodynamics such as wind speed. For the purpose of the presentation, the different storm conditions based on wave height, water levels, wind speed and beach erosion will be discussed and assessed. However, it sounds more scientifically to have the storm definition based on the hydrodynamic parameters such as wave height, water level and storm duration. Once the storm condition is defined and storm has initiated, the severity of the storm would be a question to forecast and evaluate the hazard and analyze the risk in order to determine the appropriate responses. The correlation of storm damages to the meteorological and hydrodynamics parameters can be defined as a storm scale, storm index or storm parameter and it is needed to simplify the complexity of variation involved developing the scale for risk analysis and response management. A newly introduced Coastal Storm Impulse (COSI) parameter quantifies storms into one number for a specific location and storm event. The COSI parameter is based on the conservation of linear, horizontal momentum to combine storm surge, wave dynamics, and currents over the storm duration. The COSI parameter applies the principle of conservation of momentum to physically combine the hydrodynamic variables per unit width of shoreline. This total momentum is then integrated over the duration of the storm to determine the storm's impulse to the coast. The COSI parameter employs the mean, time-averaged nonlinear (Fourier) wave momentum flux, over the wave period added to the horizontal storm surge momentum above the Mean High

  11. Balanced dynamics and convection in the tropical troposphere

    NASA Astrophysics Data System (ADS)

    Raymond, David; Fuchs, Željka; Gjorgjievska, Saška; Sessions, Sharon

    2015-09-01

    This paper presents a conceptual picture of balanced tropical tropospheric dynamics inspired by recent observations. The most important factor differentiating the tropics from middle and higher latitudes is the absence of baroclinic instability; upward motion occurs primarily via deep convective processes. Thus, convection forms an integral part of large-scale tropical motions. Since convection itself is small-scale and chaotic in detail, predictability lies in uncovering the hidden hands that guide the average behavior of convection. Two appear, balanced dynamics and thermodynamic constraints. Contrary to conventional expectations, balanced dynamics plays a crucial role in the tropical atmosphere. However, due to the smallness of the Coriolis parameter there, nonlinear balance is more important in the tropics than at higher latitudes. Three thermodynamic constraints appear to play an important role in governing the average behavior of convection outside of the cores of tropical storms. First, convection is subject to control via a lower tropospheric buoyancy quasi-equilibrium process, wherein destabilization of the lower troposphere by nonconvective processes is balanced by convective stabilization. Second, the production of precipitation is extraordinarily sensitive to the saturation fraction of the troposphere. Third, "moisture quasi-equilibrium" governs the saturation fraction, with moister atmospheres being associated with smaller moist convective instability. The moist convective instability is governed by the balanced thermodynamic response to the pattern of potential vorticity, which in turn is slowly modified by convective and radiative heating. The intricate dance between these dynamic and thermodynamic processes leads to complex behavior of the tropical atmosphere in ways that we are just beginning to understand.

  12. Spatiotemporal variability of summer precipitation in southeastern Arizona

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Walnut Gulch Experimental Watershed (WGEW) in Southeastern Arizona covers ~150 km2 and receives the majority of its annual precipitation from highly variable and intermittent summer storms during the North American Monsoon. In this study the patterns of precipitation in the United States Departm...

  13. Study of the mid-latitude ionospheric response to geomagnetic storms in the European region

    NASA Astrophysics Data System (ADS)

    Berényi, Kitti Alexandra; Barta, Veronika; Kis, Arpad

    2016-07-01

    Geomagnetic storms affect the ionospheric regions of the terrestrial upper atmosphere through different physical and atmospheric processes. The phenomena that can be regarded as a result of these processes, generally is named as "ionospheric storm". The processes depend on altitude, segment of the day, the geomagnetic latitude and longitude, strength of solar activity and the type of the geomagnetic storm. We examine the data of ground-based radio wave ionosphere sounding measurements of European ionospheric stations (mainly the data of Nagycenk Geophysical Observatory) in order to determine how and to what extent a geomagnetic disturbance of a certain strength affects the mid-latitude ionospheric regions in winter and in summer. For our analysis we used disturbed time periods between November 2012 and June 2015. Our results show significant changing of the ionospheric F2 layer parameters on strongly disturbed days compared to quiet ones. We show that the critical frequencies (foF2) increase compared to their quiet day value when the ionospheric storm was positive. On the other hand, the critical frequencies become lower, when the storm was negative. In our analysis we determined the magnitude of these changes on the chosen days. For a more complete analysis we compare also the evolution of the F2 layer parameters of the European ionosonde stations on a North-South geographic longitude during a full storm duration. The results present the evolution of an ionospheric storm over a geographic meridian. Furthermore, we compared the two type of geomagnetic storms, namely the CME caused geomagnetic storm - the so-called Sudden impulse (Si) storms- and the HSS (High Speed Solar Wind Streams) caused geomagnetic storms -the so-called Gradual storms (Gs)- impact on the ionospheric F2-layer (foF2 parameter). The results show a significant difference between the effect of Si and of the Gs storms on the ionospheric F2-layer.

  14. Stochastic Convection Parameterizations

    NASA Technical Reports Server (NTRS)

    Teixeira, Joao; Reynolds, Carolyn; Suselj, Kay; Matheou, Georgios

    2012-01-01

    computational fluid dynamics, radiation, clouds, turbulence, convection, gravity waves, surface interaction, radiation interaction, cloud and aerosol microphysics, complexity (vegetation, biogeochemistry, radiation versus turbulence/convection stochastic approach, non-linearities, Monte Carlo, high resolutions, large-Eddy Simulations, cloud structure, plumes, saturation in tropics, forecasting, parameterizations, stochastic, radiation-clod interaction, hurricane forecasts

  15. Empirical Model of Subauroral Polarization Streams (SAPS) During Geomagnetic Storms

    NASA Astrophysics Data System (ADS)

    Landry, R. G.

    2015-12-01

    Subauroral Polarization Streams (SAPS) are important electromagnetic phenomena associated with geomagnetic storms that affect the inner magnetosphere and ionosphere. They are characterized by strong sunward plasma flows caused by poleward-directed electric fields in the region of the ionosphere equatorword of the auroral zone. To examine the effects subauroral electric fields have on ITM coupling and magnetospheric-ionospheric convection we are developing an empirical model of SAPS using data acquired by the Defense Meteorological Satellite Program (DMSP) spacecraft which have made decades of in-situ measurements of ionospheric ion drifts, composition, and precipitating auroral particles. These measurements are used to characterize the subauroral electric fields relative to the location of the auroral boundary at varying magnetic local times and magnetic activity levels. As a critical component of this model, we have developed a model of the nightside zero energy electron precipitation boundary equatorward of the auroral oval parameterized by AE and MLT, using boundary identifications derived from DMSP data. We will use this model to create a global subauroral potential model and perform a superposed epoch study of SAPS fields in relationship to the auroral boundary during selected geomagnetic storms as a function of storm phase. A global empirical model of SAPS electric fields of this kind is required to realistically model thermosphere-ionosphere coupling and inner-magnetospheric convection.

  16. Lightning location relative to storm structure in a supercell storm and a multicell storm

    NASA Technical Reports Server (NTRS)

    Ray, Peter S.; Macgorman, Donald R.; Rust, W. David; Taylor, William L.; Rasmussen, Lisa Walters

    1987-01-01

    Relationships between lightning location and storm structure are examined for one radar volume scan in each of two mature, severe storms. One of these storms had characteristics of a supercell storm, and the other was a multicell storm. Data were analyzed from dual-Doppler radar and dual-VHF lightning-mapping systems. The distributions of VHF impulse sources were compared with radar reflectivity, vertical air velocity, and their respective gradients. In the supercell storm, lightning tended to occur along streamlines above and down-shear of the updraft and reflectivity cores; VHF impulse sources were most concentrated in reflectivities between 30 and 40 dBZ and were distributed uniformly with respect to updraft speed. In the multicell storm, on the other hand, lightning tended to coincide with the vertical reflectivity and updraft core and with the diverging streamlines near the top of the storm. The results suggest that the location of lightning in these severe storms were most directly associated with the wind field structure relative to updraft and reflectivity cores. Since the magnitude and vertical shear of the environmental wind are fundamental in determining the reflectivity and wind field structure of a storm, it is suggested that these environmental parameters are also fundamental in determining lightning location.

  17. Empirical STORM-E Model. [I. Theoretical and Observational Basis

    NASA Technical Reports Server (NTRS)

    Mertens, Christopher J.; Xu, Xiaojing; Bilitza, Dieter; Mlynczak, Martin G.; Russell, James M., III

    2013-01-01

    Auroral nighttime infrared emission observed by the Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) instrument onboard the Thermosphere-Ionosphere-Mesosphere Energetics and Dynamics (TIMED) satellite is used to develop an empirical model of geomagnetic storm enhancements to E-region peak electron densities. The empirical model is called STORM-E and will be incorporated into the 2012 release of the International Reference Ionosphere (IRI). The proxy for characterizing the E-region response to geomagnetic forcing is NO+(v) volume emission rates (VER) derived from the TIMED/SABER 4.3 lm channel limb radiance measurements. The storm-time response of the NO+(v) 4.3 lm VER is sensitive to auroral particle precipitation. A statistical database of storm-time to climatological quiet-time ratios of SABER-observed NO+(v) 4.3 lm VER are fit to widely available geomagnetic indices using the theoretical framework of linear impulse-response theory. The STORM-E model provides a dynamic storm-time correction factor to adjust a known quiescent E-region electron density peak concentration for geomagnetic enhancements due to auroral particle precipitation. Part II of this series describes the explicit development of the empirical storm-time correction factor for E-region peak electron densities, and shows comparisons of E-region electron densities between STORM-E predictions and incoherent scatter radar measurements. In this paper, Part I of the series, the efficacy of using SABER-derived NO+(v) VER as a proxy for the E-region response to solar-geomagnetic disturbances is presented. Furthermore, a detailed description of the algorithms and methodologies used to derive NO+(v) VER from SABER 4.3 lm limb emission measurements is given. Finally, an assessment of key uncertainties in retrieving NO+(v) VER is presented

  18. Communicating Storm Surge Forecast Uncertainty

    NASA Astrophysics Data System (ADS)

    Troutman, J. A.; Rhome, J.

    2015-12-01

    When it comes to tropical cyclones, storm surge is often the greatest threat to life and property along the coastal United States. The coastal population density has dramatically increased over the past 20 years, putting more people at risk. Informing emergency managers, decision-makers and the public about the potential for wind driven storm surge, however, has been extremely difficult. Recently, the Storm Surge Unit at the National Hurricane Center in Miami, Florida has developed a prototype experimental storm surge watch/warning graphic to help communicate this threat more effectively by identifying areas most at risk for life-threatening storm surge. This prototype is the initial step in the transition toward a NWS storm surge watch/warning system and highlights the inundation levels that have a 10% chance of being exceeded. The guidance for this product is the Probabilistic Hurricane Storm Surge (P-Surge) model, which predicts the probability of various storm surge heights by statistically evaluating numerous SLOSH model simulations. Questions remain, however, if exceedance values in addition to the 10% may be of equal importance to forecasters. P-Surge data from 2014 Hurricane Arthur is used to ascertain the practicality of incorporating other exceedance data into storm surge forecasts. Extracting forecast uncertainty information through analyzing P-surge exceedances overlaid with track and wind intensity forecasts proves to be beneficial for forecasters and decision support.

  19. Storm impact for barrier islands

    USGS Publications Warehouse

    Sallenger,, Asbury H., Jr.

    2000-01-01

    A new scale is proposed that categorizes impacts to natural barrier islands resulting from tropical and extra-tropical storms. The proposed scale is fundamentally different than existing storm-related scales in that the coupling between forcing processes and the geometry of the coast is explicitly included. Four regimes, representing different levels of impact, are defined. Within each regime, patterns and relative magnitudes of net erosion and accretion are argued to be unique. The borders between regimes represent thresholds defining where processes and magnitudes of impacts change dramatically. Impact level 1 is the 'swash' regime describing a storm where runup is confined to the foreshore. The foreshore typically erodes during the storm and recovers following the storm; hence, there is no net change. Impact level 2 is the 'collision' regime describing a storm where the wave runup exceeds the threshold of the base of the foredune ridge. Swash impacts the dune forcing net erosion. Impact level 3 is the 'overwash' regime describing a storm where wave runup overtops the berm or, if present, the foredune ridge. The associated net landward sand transport contributes to net migration of the barrier landward. Impact level 4 is the 'inundation' regime describing a storm where the storm surge is sufficient to completely and continuously submerge the barrier island. Sand undergoes net landward transport over the barrier island; limited evidence suggests the quantities and distance of transport are much greater than what occurs during the 'overwash' regime.

  20. Investigation of Ring Current Response to CIR-Driven Geomagnetic Storms

    NASA Astrophysics Data System (ADS)

    Cramer, William Douglas

    The physics of ring current behavior during Coronal Mass Ejection (CME)-driven storms is well understood and can be modeled with moderate accuracy. The effects of Corotating Interaction Region (CIR)-driven storms are less understood and tend to not agree with expected values. Various approaches are employed to examine the differences in ring current behavior during storms driven by these two types of events. Satellite data (Polar CAM-MICE/MICS) are analyzed to determine differences in pitch angle distributions and energy densities, in order to provide insight into how the various ring current enhancement and loss processes differ during the different types of events. A ring current model (the Comprehensive Ring Current Model) is also employed to analyze these differences by modeling ring current behavior during CME and CIR events that fit a typical solar wind profile. No differences in convection were noted in satellite data during CME and CIR-driven storms of similar strength, although oxygen was found to contribute more to the energy density during CIRs. However, model results demonstrated that there is a significant difference in ring current response during storms associated with the different drivers. It was determined that particle convection appears to be the primary ring current energization mechanism for CME-driven events, while other factors seem to influence the induced surface magnetic disturbance during CIR-driven storms; possibly boundary conditions, external currents or fluctuations caused by the associated wave-induced oscillations in the solar wind.

  1. The Impact of Land Cover Change on a Simulated Storm Event in the Sydney Basin

    NASA Astrophysics Data System (ADS)

    Gero, A. F.; Pitman, A. J.

    2006-02-01

    The Regional Atmospheric Modeling System (RAMS) was run at a 1-km grid spacing over the Sydney basin in Australia to assess the impact of land cover change on a simulated storm event. The simulated storm used NCEP NCAR reanalysis data, first with natural (i.e., pre-European settlement in 1788) land cover and then with satellite-derived land cover representing Sydney's current land use pattern. An intense convective storm develops in the model in close proximity to Sydney's dense urban central business district under current land cover. The storm is absent under natural land cover conditions. A detailed investigation of why the change in land cover generates a storm was performed using factorial analysis, which revealed the storm to be sensitive to the presence of agricultural land in the southwest of the domain. This area interacts with the sea breeze and affects the horizontal divergence and moisture convergence—the triggering mechanisms of the storm. The existence of the storm over the dense urban area of Sydney is therefore coincidental. The results herein support efforts to develop parameterization of urban surfaces in high-resolution simulations of Sydney's meteorological environment but also highlight the need to improve the parameterization of other types of land cover change at the periphery of the urban area, given that these types dominate the explanation of the results.

  2. Mechanisms initiating deep convection over complex terrain during COPS.

    SciTech Connect

    Kottmeier, C.; Kalthoff, N.; Barthlott, C.; Corsmeier, U.; Van Baelen, J.; Coulter, R.; Environmental Science Division; Inst. for Meteorology and Climate Research; Lab. de Meteorologie Physique; Inst. of Physics and Meteorology

    2008-12-01

    Precipitating convection in a mountain region of moderate topography is investigated, with particular emphasis on its initiation in response to boundary-layer and mid- and upper-tropospheric forcing mechanisms. The data used in the study are from COPS (Convective and Orographically-induced Precipitation Study) that took place in southwestern Germany and eastern France in the summer of 2007. It is found that the initiation of precipitating convection can be roughly classified as being due to either: (i) surface heating and low-level flow convergence; (ii) surface heating and moisture supply overcoming convective inhibition during latent and/or potential instability; or (iii) mid-tropospheric dynamical processes due to mesoscale convergence lines and forced mean vertical motion. These phenomena have to be adequately represented in models in order to improve quantitative precipitation forecast. Selected COPS cases are analyzed and classified into these initiation categories. Although only a subset of COPS data (mainly radiosondes, surface weather stations, radar and satellite data) are used here, it is shown that convective systems are captured in considerable detail by sensor synergy. Convergence lines were observed by Doppler radar in the location where deep convection is triggered several hours later. The results suggest that in many situations, observations of the location and timing of convergence lines will facilitate the nowcasting of convection. Further on, forecasting of the initiation of convection is significantly complicated if advection of potentially convective air masses over changing terrain features plays a major role. The passage of a frontal structure over the Vosges - Rhine valley - Black Forest orography was accompanied by an intermediate suppression of convection over the wide Rhine valley. Further downstream, an intensification of convection was observed over the Black Forest due to differential surface heating, a convergence line, and the flow

  3. Assessment of the Pseudo Geostationary Lightning Mapper Products at the Spring Program and Summer Experiment

    NASA Technical Reports Server (NTRS)

    Stano, Geoffrey T.; Calhoun, Kristin K.; Terborg, Amanda M.

    2014-01-01

    Since 2010, the de facto Geostationary Lightning Mapper (GLM) demonstration product has been the Pseudo-Geostationary Lightning Mapper (PGLM) product suite. Originally prepared for the Hazardous Weather Testbed's Spring Program (specifically the Experimental Warning Program) when only four ground-based lightning mapping arrays were available, the effort now spans collaborations with several institutions and eight collaborative networks. For 2013, NASA's Short-term Prediction Research and Transition (SPoRT) Center and NOAA's National Severe Storms Laboratory have worked to collaborate with each network to obtain data in real-time. This has gone into producing the SPoRT variant of the PGLM that was demonstrated in AWIPS II for the 2013 Spring Program. Alongside the PGLM products, the SPoRT / Meteorological Development Laboratory's total lightning tracking tool also was evaluated to assess not just another visualization of future GLM data but how to best extract more information while in the operational environment. Specifically, this tool addressed the leading request by forecasters during evaluations; provide a time series trend of total lightning in real-time. In addition to the Spring Program, SPoRT is providing the PGLM "mosaic" to the Aviation Weather Center (AWC) and Storm Prediction Center. This is the same as what is used at the Hazardous Weather Testbed, but combines all available networks into one display for use at the national centers. This year, the mosaic was evaluated during the AWC's Summer Experiment. An important distinction between this and the Spring Program is that the Summer Experiment focuses on the national center perspective and not at the local forecast office level. Specifically, the Summer Experiment focuses on aviation needs and concerns and brings together operational forecaster, developers, and FAA representatives. This presentation will focus on the evaluation of SPoRT's pseudo-GLM products in these separate test beds. The emphasis

  4. The News, Summer 1999-Summer 2000.

    ERIC Educational Resources Information Center

    Robertson, Trische, Ed.

    2000-01-01

    This document contains five quarterly issues of The News, published Summer 1999 through Summer 2000 by the Community College League of California. The following items are contained in this document: "Grant Writing Success Depends on Resources, Information and Staff,""College Theaters Perform Balancing Act with Community, Instruction,…

  5. The Tropical Convective Spectrum. Part 1; Archetypal Vertical Structures

    NASA Technical Reports Server (NTRS)

    Boccippio, Dennis J.; Petersen, Walter A.; Cecil, Daniel J.

    2005-01-01

    A taxonomy of tropical convective and stratiform vertical structures is constructed through cluster analysis of 3 yr of Tropical Rainfall Measuring Mission (TRMM) "warm-season" (surface temperature greater than 10 C) precipitation radar (PR) vertical profiles, their surface rainfall, and associated radar-based classifiers (convective/ stratiform and brightband existence). Twenty-five archetypal profile types are identified, including nine convective types, eight stratiform types, two mixed types, and six anvil/fragment types (nonprecipitating anvils and sheared deep convective profiles). These profile types are then hierarchically clustered into 10 similar families, which can be further combined, providing an objective and physical reduction of the highly multivariate PR data space that retains vertical structure information. The taxonomy allows for description of any storm or local convective spectrum by the profile types or families. The analysis provides a quasi-independent corroboration of the TRMM 2A23 convective/ stratiform classification. The global frequency of occurrence and contribution to rainfall for the profile types are presented, demonstrating primary rainfall contribution by midlevel glaciated convection (27%) and similar depth decaying/stratiform stages (28%-31%). Profiles of these types exhibit similar 37- and 85-GHz passive microwave brightness temperatures but differ greatly in their frequency of occurrence and mean rain rates, underscoring the importance to passive microwave rain retrieval of convective/stratiform discrimination by other means, such as polarization or texture techniques, or incorporation of lightning observations. Close correspondence is found between deep convective profile frequency and annualized lightning production, and pixel-level lightning occurrence likelihood directly tracks the estimated mean ice water path within profile types.

  6. Is tropopause folding promoting or suppressing deep convection? First results from TROSIAD

    NASA Astrophysics Data System (ADS)

    Antonescu, B.; Vaughan, G.; Schultz, D. M.

    2012-04-01

    The occurrence, timing, and location of deep, moist convection remains a problem for operational weather forecasting, despite the rapid development of the numerical weather prediction models and implementation of new observational techniques. One impediment to better forecasting of deep convection is the role played by tropopause folds. How deep convection is modulated by tropopause folding, which brings stratospheric air into the troposphere, is not well understood. Three ingredients are required for deep moist, convection- moisture, instability, and lift-and all three ingredients associated with tropopause folds can either promote or suppress convection. For example, the dry air associated with the descent of upper-tropospheric air may limit the vertical development of buoyant thermals, yet this dry air may also create potential instability. The purpose of the research project TROSIAD is to assess the importance for convection forecasting of correctly representing tropopause folds in numerical weather forecasting models and to disentangle the conflicting paradigms that tropopause folds both promote and suppress convection. The work plan of the project involves the analysis of existing data from the Mesosphere-Stratosphere-Troposphere (MST) Radar at Aberystwyth, UK, which can measure both tropopause folds and convection, a number of cases studies from measurement campaigns, and numerical modelling experiments. The project begins with building 5-year (2006-2010) climatologies of radar data, and wind-profiling data to determine the relationship between tropopause folds and deep moist convection. Using data from Met Office NIMROD radar network, a climatology of all convective storms with the track in study region was developed. To be included in the climatology, a convective storm must persist for at least 30 minutes with a maximum radar reflectivity greater than 30 dBZ. A total of 663 convective storms were identified. A climatology of the tropopause folds over

  7. Structure of the Highly Sheared Tropical Storm Chantal During CAMEX-4

    NASA Technical Reports Server (NTRS)

    Heymsfield, G. M.; Halverson, J.; Ritchie, E.; Simpson, Joanne; Molinari, J.; Tian, L.

    2004-01-01

    NASA's 4th Convection and Moisture Experiment (CAMEX-4) focused on Atlantic hurricanes during the 2001 hurricane season and it involved both NASA and NOAA participation. The NASA ER-2 and DC-8 aircraft were instrumented with unique remote sensing instruments to help increase the overall understanding of hurricanes. This paper is concerned about one of the storms studied, Tropical Storm Chantal, that was a weak storm which failed to intense into a hurricane. One of the practical questions of high importance is why some tropical stoins intensify into hurricanes, and others remain weak or die altogether. The magnitude of the difference between the horizontal winds at lower levels and upper altitudes in a tropical storm, i.e., the wind shear, is one important quantity that can affect the intensification of a tropical storm. Strong shear as was present during Tropical Storm Chantal s lifetime and it was detrimental to its intensification. The paper presents an analysis of unique aircraft observations collected from Chantal including an on-board radar, radiometers, dropsondes, and flight level measurements. These measurements have enabled us to examine the internal structure of the winds and thermal structure of Chantal. Most of the previous studies have involved intense hurricanes that overcame the effects of shear and this work has provided new insights into what prevents a weaker storm from intensifying. The storm had extremely intense thunderstorms and rainfall, yet its main circulation was confined to low levels of the atmosphere. Chantal's thermal structure was not configured properly for the storm to intensify. It is most typical that huricanes have a warm core structure where warm temperatures in upper levels of a storm s circulation help intensify surface winds and lower its central pressure. Chantal had two weaker warm layers instead of a well-defined warm core. These layers have been related to the horizontal and vertical winds and precipitation structure and

  8. Changes of seasonal storm properties in California and Nevada from an ensemble of climate projections

    NASA Astrophysics Data System (ADS)

    Yu, Zhongbo; Jiang, Peng; Gautam, Mahesh R.; Zhang, Yong; Acharya, Kumud

    2015-04-01

    Precipitation characteristics, such as intensity, frequency, duration, and event pattern, are changing due to the increases in greenhouse gases, transition of ocean oscillation phases, etc. In this paper, we evaluate the ability of 11 realizations from multiple regional climate model (RCM)/global climate model pairs in the North American Regional Climate Change Assessment Program (NARCCAP) to simulate the seasonal variability and magnitude of storm properties, including storm duration, interstorm period, and storm intensity. The results indicate that NARCCAP RCMs simulate the seasonal variability better in the Greater Sacramento and San Joaquin than in Las Vegas, which may be due to the RCMs' inability to simulate local convective precipitation associated with the North American Monsoon. We also investigate the impacts of climate change on these storm characteristics by comparing the percentage change and absolute change of storm properties determined from NARCCAP historical runs and future runs. We find that individual RCMs exhibit great uncertainty in the percentage changes in storm duration, interstorm period, and average storm intensity. The ensemble means of storm properties across 11 future NARCCAP RCM projections show different responses to climate change in different locations. Our analyses provide guidelines for selecting the appropriate RCMs for hydrologic studies related to storm properties and provide forecasters and water managers with detailed information of future changes in storm properties so that they can sustainably manage water resources. Our results may also contribute to the nonstationary precipitation scenario development by incorporating the percentage changes of storm properties caused by human-induced warming into the stochastic precipitation model.

  9. Severe storm electricity

    NASA Technical Reports Server (NTRS)

    Rust, W. D.; Macgorman, D. R.; Taylor, W.; Arnold, R. T.

    1984-01-01

    Severe storms and lightning were measured with a NASA U2 and ground based facilities, both fixed base and mobile. Aspects of this program are reported. The following results are presented: (1) ground truth measurements of lightning for comparison with those obtained by the U2. These measurements include flash type identification, electric field changes, optical waveforms, and ground strike location; (2) simultaneous extremely low frequency (ELF) waveforms for cloud to ground (CG) flashes; (3) the CG strike location system (LLP) using a combination of mobile laboratory and television video data are assessed; (4) continued development of analog-to-digital conversion techniques for processing lightning data from the U2, mobile laboratory, and NSSL sensors; (5) completion of an all azimuth TV system for CG ground truth; (6) a preliminary analysis of both IC and CG lightning in a mesocyclone; and (7) the finding of a bimodal peak in altitude lightning activity in some storms in the Great Plains and on the east coast. In the forms on the Great Plains, there was a distinct class of flash what forms the upper mode of the distribution. These flashes are smaller horizontal extent, but occur more frequently than flashes in the lower mode of the distribution.

  10. Solar radio continuum storms

    NASA Technical Reports Server (NTRS)

    Sakurai, K.

    1976-01-01

    The paper reviews the current status of research on solar radio continuum emissions from metric to hectometric wave frequencies, emphasizing the role of energetic electrons in the 10-100 keV range in these emissions. It is seen that keV-energy electrons generated in active sunspot groups must be the sources of radio continuum storm emissions for wide frequency bands. These electrons excite plasma oscillations in the medium, which in turn are converted to electromagnetic radiation. The radio noise continuum sources are usually associated with type III burst activity observed above these sources. Although the mechanism for the release of the energetic electrons is not known, it seems they are ejected from storm source regions in association with rapid variation of associated sunspot magnetic fields due to their growth into complex types. To explain some of the observed characteristics, the importance of two-stream instability and the scattering of ambient plasma ions on energetic electron streams is pointed out.

  11. Magneto-convection.

    PubMed

    Stein, Robert F

    2012-07-13

    Convection is the transport of energy by bulk mass motions. Magnetic fields alter convection via the Lorentz force, while convection moves the fields via the curl(v×B) term in the induction equation. Recent ground-based and satellite telescopes have increased our knowledge of the solar magnetic fields on a wide range of spatial and temporal scales. Magneto-convection modelling has also greatly improved recently as computers become more powerful. Three-dimensional simulations with radiative transfer and non-ideal equations of state are being performed. Flux emergence from the convection zone through the visible surface (and into the chromosphere and corona) has been modelled. Local, convectively driven dynamo action has been studied. The alteration in the appearance of granules and the formation of pores and sunspots has been investigated. Magneto-convection calculations have improved our ability to interpret solar observations, especially the inversion of Stokes spectra to obtain the magnetic field and the use of helioseismology to determine the subsurface structure of the Sun. PMID:22665893

  12. A study of severe storm electricity via storm intercept

    NASA Technical Reports Server (NTRS)

    Arnold, Roy T.; Horsburgh, Steven D.; Rust, W. David; Burgess, Don

    1985-01-01

    Storm electricity data, radar data, and visual observations were used both to present a case study for a supercell thunderstorm that occurred in the Texas Panhandle on 19 June 1980 and to search for insight into how lightning to ground might be related to storm dynamics in the updraft/downdraft couplet in supercell storms. It was observed that two-thirds of the lightning ground-strike points in the developing and maturing stages of a supercell thunderstorm occurred within the region surrounding the wall cloud (a cloud feature often characteristic of a supercell updraft) and on the southern flank of the precipitation. Electrical activity in the 19 June 1980 storm was atypical in that it was a right-mover. Lightning to ground reached a peak rate of 18/min and intracloud flashes were as frequent as 176/min in the final stages of the storm's life.

  13. On the Variations of Electricity, Lightning and Storm Properties

    NASA Astrophysics Data System (ADS)

    Peterson, M. J.; Deierling, W.; Liu, C.; Mach, D. M.; Kalb, C. P.

    2015-12-01

    Electrified clouds -thunderstorms if lightning is detected, and electrified shower clouds otherwise - produce various currents that contribute to the Global Electric Circuit (GEC). This study aims to use observations of storm properties and lightning characteristics, as well as passive microwave estimates of above-cloud electric fields to compare possible current contributions from a wide variety of storms including isolated thunderstorms, Mesoscale Convective Systems, and otherwise similar storms that occur over land or over the ocean. Variations in Lightning Imaging Sensor (LIS) optical flash properties are also considered in the context of how they relate to the properties of the parent storm and why they differ substantially between land and ocean. This study relies on observations from the Tropical Rainfall Measuring Mission (TRMM) satellite that include radar profiles from the Precipitation Radar (PR), passive microwave observations from the TRMM Microwave Imager (TMI), infrared imagery from the Visible and Infrared Scanner (VIRS), and optical lightning observations from LIS. Observations and derived parameters such as rain rates and electric field estimates are integrated into two databases: a Precipitation Feature (PF) database that summarizes the properties of storms defined by near surface rainfall, and an Illuminated Cloud Feature (ICF) database that summarizes the properties of the storm region illuminated by LIS lightning flashes. The ICF database is built to examine factors that are related to how optical energy can be distributed across the flash footprint in different types of clouds and different viewing conditions that will have consequences for the Geostationary Lightning Mapper (GLM) onboard the upcoming GOES-R satellite.

  14. The Influence of Land Surface Heterogeneities on Heavy Convective Rainfall in the Baltimore-Washington Metropolitan Area

    NASA Astrophysics Data System (ADS)

    Ryu, Young-Hee; Smith, James; Baeck, Mary Lynn; Bou-Zeid, Elie

    2015-04-01

    We perform numerical experiments using the Weather Research and Forecasting model to examine the influence of land surface heterogeneities on heavy convective rainfall in the Baltimore-Washington Metropolitan Area. Numerical experiments are carried out for a storm system (1-2 June 2012) in which heavy rainfall and severe weather were organized in the warm sector ahead of a rapidly moving cold front. As shown in previous studies, the environment is typical of flash flood producing storm systems for urban areas of the eastern US. The storm system produced rainfall accumulations exceeding 80 mm and major flash flooding in Baltimore watersheds. The study region is adjacent to the Chesapeake Bay and includes the second largest urban agglomeration in the eastern US. Numerical experiments examine urban impacts on rainfall using the Princeton Urban Canopy Model and the Noah Land Surface Model. We also examine the role of "Bay Breeze" circulations from the Chesapeake Bay for convective evolution. Rainfall distribution and amount are better represented for experiments using the more realistic urban canopy model. The Bay Breeze plays a central role in formation of convergence lines that are major determinants of convective evolution with the approaching line of convection. The Bay Breeze also interacts with heterogeneous surface fluxes from urban landscapes to determine moisture transport to evolving storm systems. The low-level convergence lines and water vapor transport that are induced and modified by land surface heterogeneities are crucial for the preferred locations of strong convective storms and heavy rainfall over the Baltimore Washington metropolitan area.

  15. Modeling the Interaction of Moist Convection with the Zonal Jets of Jupiter

    NASA Astrophysics Data System (ADS)

    Li, L.; Ingersoll, A. P.

    2004-11-01

    We use a reduced-gravity quasi-geostrophic model with a parameterization of moist convection that is based on Galileo and Cassini observations of lightning and convective storms (Little et al., 1999; Gierasch et al., 2000; Porco et al., 2003). The features of the jets we want to reproduce in the model include: (1) the curvature of the zonal jet profile, which violates the barotropic stability criterion near many of the westward jets (Ingersoll et al., 1981; Li et al., 2004), (2) the speed of the zonal jets, which is related to their width, given that the jets marginally violate the barotropic stability criterion, and (3) the sign of the eddy momentum flux, which is into the jets and tends to sustain them (Beebe et al., 1979; Ingersoll et al., 1981; Salyk et al., 2004). The features of moist convective storms that are taken from observation include: (1) the tendency of the storms to occur in the cyclonic belts, (2) the rapid divergence of horizontal velocity near the cloud tops, and (3) the lifetime of the storms, which is on average 4-5 days (Li et al., 2004). We find that moist convection leads to zonal jets in the upper layer, but the jets violate the barotropic stability criterion only if the flow in the deep underlying layer is westward. We can reproduce the chevron shape on the sides of the jets if we postulate that the clouds persist longer than the storms that produce them. We can reproduce the number and frequency of moist convection storms by assuming that they carry most of the planet's vertical heat flux (Gierasch et al., 2000). The NASA Planetary Atmospheres Program supported this research.

  16. Pulsation driving and convection

    NASA Astrophysics Data System (ADS)

    Antoci, Victoria

    2015-08-01

    Convection in stellar envelopes affects not only the stellar structure, but has a strong impact on different astrophysical processes, such as dynamo-generated magnetic fields, stellar activity and transport of angular momentum. Solar and stellar observations from ground and space have shown that the turbulent convective motion can also drive global oscillations in many type of stars, allowing to study stellar interiors at different evolutionary stages. In this talk I will concentrate on the influence of convection on the driving of stochastic and coherent pulsations across the Hertzsprung-Russell diagram and give an overview of recent studies.

  17. Role of wetlands in attenuation of storm surges using coastal circulation model (ADCIRC), Chesapeake Bay region

    NASA Astrophysics Data System (ADS)

    Deb, Mithun; Ferreira, Celso; Lawler, Seth

    2014-05-01

    The Chesapeake Bay, Virginia is subject to storm surge from extreme weather events nearly year-round; from tropical storms and hurricanes during the summer and fall, (e.g., hurricanes Isabel [2003] and Sandy [2012]), and from nor'easters during the winter (e.g., winter storms Nemo and Saturn [2013]). Coastal wetlands can deliver acute fortification against incoming hurricane storm surges. Coastal wetlands and vegetation shape the hydrodynamics of storm surge events by retaining water and slowing the propagation of storm surge, acting as a natural barrier to flooding. Consequently, a precise scheme to quantify the effect of wetlands on coastal surge levels was also prerequisite. Two wetland sites were chosen in the Chesapeake Bay region for detailed cataloging of vegetation characteristics, including: height, stem diameter, and density. A framework was developed combining these wetlands characterizations with numerical simulations. Storms surges were calculated using Coastal circulation model (ADCIRC) coupled to a wave model (SWAN) forced by an asymmetric hurricane vortex model using an unstructured mesh (comprised of 1.8 million nodes) under a High Performance Computing environment. The Hurricane Boundary Layer (HBL) model was used to compute wind and pressure fields for historical tropical storms and for all of the synthetic storms. Wetlands were characterized in the coupled numerical models by bathymetric and frictional resistance. Multiple model simulations were performed using historical hurricane data and hypothetical storms to compare the predicted storm surge inundation resulting from various levels of wetlands expansion or reduction. The results of these simulations demonstrate the efficacy of wetlands in storm surge attenuation and also the outcome will scientifically support planning of wetlands restoration projects with multi-objective benefits for society.

  18. Methane storms as a driver of Titan's dune orientation

    NASA Astrophysics Data System (ADS)

    Charnay, Benjamin; Barth, Erika; Rafkin, Scot; Narteau, Clément; Lebonnois, Sébastien; Rodriguez, Sébastien; Courrech Du Pont, Sylvain; Lucas, Antoine

    2015-05-01

    The equatorial regions of Saturn's moon Titan are covered by linear dunes that propagate eastwards. Global climate models (GCMs), however, predict westward mean surface winds at low latitudes on Titan, similar to the trade winds on Earth. This apparent contradiction has been attributed to Saturn's gravitational tides, large-scale topography and wind statistics, but none of these hypotheses fully explains the global eastward propagation of dunes in Titan's equatorial band. However, above altitudes of about 5 km, Titan's atmosphere is in eastward super-rotation, suggesting that this momentum may be delivered to the surface. Here we assess the influence of equatorial tropical methane storms--which develop at high altitudes during the equinox--on Titan's dune orientation, using mesoscale simulations of convective methane clouds with a GCM wind profile that includes super-rotation. We find that these storms produce fast eastward gust fronts above the surface that exceed the normal westward surface winds. These episodic gusts generated by tropical storms are expected to dominate aeolian transport, leading to eastward propagation of dunes. We therefore suggest a coupling between super-rotation, tropical methane storms and dune formation on Titan. This framework, applied to GCM predictions and analogies to some terrestrial dune fields, explains the linear shape, eastward propagation and poleward divergence of Titan's dunes, and implies an equatorial origin of dune sand.

  19. Mars Atmospheric Chemistry in Electrified Dust Devils and Storms

    NASA Technical Reports Server (NTRS)

    Farrell, W. M.; Delory, G. T.; Atreya, S. K.; Wong, A.-S.; Renno, N. O.; Sentmann, D. D.; Marshall, J. G.; Cummer, S. A.; Rafkin, S.; Catling, D.

    2005-01-01

    Laboratory studies, simulations and desert field tests all indicate that aeolian mixing dust can generate electricity via contact electrification or "triboelectricity". In convective structures like dust devils or storms, grain stratification (or charge separation) occurs giving rise to an overall electric dipole moment to the aeolian feature, similar in nature to the dipolar electric field generated in terrestrial thunderstorms. Previous simulation studies [1] indicate that this storm electric field on Mars can approach atmospheric breakdown field strength of 20 kV/m. In terrestrial dust devils, coherent dipolar electric fields exceeding 20 kV/m have been measured directly via electric field instrumentation. Given the expected electrostatic fields in Martian dust devils and storms, electrons in the low pressure CO2 gas can be energized via the electric field to values exceeding the electron dissociative attachment energy of both CO2 and H2O, resulting in the formation of new chemical products CO and O- and OH and H- within the storm. Using a collisional plasma physics model we present a calculation of the CO/O- and OH/H- reaction and production rates. We demonstrate that these rates vary geometrically with ambient electric field, with substantial production of dissociative products when fields approach breakdown levels of 20-30 kV/m.

  20. Outreach Plans for Storm Peak Laboratory

    NASA Astrophysics Data System (ADS)

    Hallar, A. G.; McCubbin, I. B.

    2006-12-01

    The Desert Research Institute (DRI) operates a high elevation facility, Storm Peak Laboratory (SPL), located on the west summit of Mt. Werner in the Park Range near Steamboat Springs, Colorado at an elevation 10,500 ft. SPL provides an ideal location for long-term research on the interactions of atmospheric aerosol and gas- phase chemistry with cloud and natural radiation environments. SPL includes an office-type laboratory room for computer and instrumentation setup with outside air ports and cable access to the roof deck, a full kitchen and two bunk rooms with sleeping space for nine persons. We plan to create a unique summer undergraduate education experiences for students of diversity at Storm Peak Laboratory. As stressed by the College Pathways to Science Education Standards [Siebert and McIntosh, 2001], to support changes in K-12 science education transformations must first be made at the college level, including inquiry-oriented opportunities to engage in meaningful research. These workshops will be designed to allow students to experience the excitement of science, increasing their likelihood of pursing careers within the fields of scientific education or research.

  1. Extreme Lightning Flash Rates as an Early Indicator of Severe Storms

    NASA Technical Reports Server (NTRS)

    Goodman, Steven J.; Arnold, James E. (Technical Monitor)

    2002-01-01

    Extreme lightning flash rates are proving to be an early indicator of intensifying storms capable of producing tornadoes, damaging winds and hail. Most of this lightning is in the cloud, where the naked eye can not see it. Recent global observations of thunderstorms from space indicate that giant electrical storms (supercells and convective complexes) with flash rates on the order of 1 flash per second are most common over the land masses of the America sub-tropics and equatorial Congo Basin. Within the United States, the average tornado warning lead time on a national basis is about 11 min. The real-time observation of extreme flash rates and the rapid increase in the in-cloud flash rate, signalling the intensification of the storm updraft, may provide as much as a 50% increase in severe storm warning lead time.

  2. Topographic signatures of spatially-limited storm morphologies revealed from numerical landscape evolution modelling

    NASA Astrophysics Data System (ADS)

    Valters, Declan; Brocklehurst, Simon

    2016-04-01

    Landscape evolution models typically forsake realistic spatial and temporal patterns of rainfall, assuming spatially uniform rainfall input and steady-state runoff conditions. The implications of this assumption are explored, using extensions made to the CHILD numerical landscape evolution model. A variety of rainfall distribution patterns are tested - from isolated intense storm cells associated with convective precipitation, to more extensive rainfall patterns associated with frontal or stratiform types of precipitation. Several topographic metrics are used to quantify the imprint left by variations in dominant storm shape and size, including the channel steepness (ksn) and chi (χ) gradient indices. All else being equal, resultant landscape topography is shown to be sensitive to the dominant storm morphology and storm cell positioning at the range and catchment scales.

  3. Thyroid storm: an updated review.

    PubMed

    Chiha, Maguy; Samarasinghe, Shanika; Kabaker, Adam S

    2015-03-01

    Thyroid storm, an endocrine emergency first described in 1926, remains a diagnostic and therapeutic challenge. No laboratory abnormalities are specific to thyroid storm, and the available scoring system is based on the clinical criteria. The exact mechanisms underlying the development of thyroid storm from uncomplicated hyperthyroidism are not well understood. A heightened response to thyroid hormone is often incriminated along with increased or abrupt availability of free hormones. Patients exhibit exaggerated signs and symptoms of hyperthyroidism and varying degrees of organ decompensation. Treatment should be initiated promptly targeting all steps of thyroid hormone formation, release, and action. Patients who fail medical therapy should be treated with therapeutic plasma exchange or thyroidectomy. The mortality of thyroid storm is currently reported at 10%. Patients who have survived thyroid storm should receive definite therapy for their underlying hyperthyroidism to avoid any recurrence of this potentially fatal condition.

  4. Effects of explicit atmospheric convection at high CO2.

    PubMed

    Arnold, Nathan P; Branson, Mark; Burt, Melissa A; Abbot, Dorian S; Kuang, Zhiming; Randall, David A; Tziperman, Eli

    2014-07-29

    The effect of clouds on climate remains the largest uncertainty in climate change predictions, due to the inability of global climate models (GCMs) to resolve essential small-scale cloud and convection processes. We compare preindustrial and quadrupled CO2 simulations between a conventional GCM in which convection is parameterized and a "superparameterized" model in which convection is explicitly simulated with a cloud-permitting model in each grid cell. We find that the global responses of the two models to increased CO2 are broadly similar: both simulate ice-free Arctic summers, wintertime Arctic convection, and enhanced Madden-Julian oscillation (MJO) activity. Superparameterization produces significant differences at both CO2 levels, including greater Arctic cloud cover, further reduced sea ice area at high CO2, and a stronger increase with CO2 of the MJO.

  5. Effects of explicit atmospheric convection at high CO2

    PubMed Central

    Arnold, Nathan P.; Branson, Mark; Burt, Melissa A.; Abbot, Dorian S.; Kuang, Zhiming; Randall, David A.; Tziperman, Eli

    2014-01-01

    The effect of clouds on climate remains the largest uncertainty in climate change predictions, due to the inability of global climate models (GCMs) to resolve essential small-scale cloud and convection processes. We compare preindustrial and quadrupled CO2 simulations between a conventional GCM in which convection is parameterized and a “superparameterized” model in which convection is explicitly simulated with a cloud-permitting model in each grid cell. We find that the global responses of the two models to increased CO2 are broadly similar: both simulate ice-free Arctic summers, wintertime Arctic convection, and enhanced Madden–Julian oscillation (MJO) activity. Superparameterization produces significant differences at both CO2 levels, including greater Arctic cloud cover, further reduced sea ice area at high CO2, and a stronger increase with CO2 of the MJO. PMID:25024204

  6. Observations and Modeling of the June 22-23 Storm

    NASA Astrophysics Data System (ADS)

    Reiff, Patricia; Daou, Antoun; Sazykin, Stan; Coffey, Victoria; Nakamura, Rumi; Anderson, Brian; Hairston, Marc; Mauk, Barry; Russel, Chris; Baker, Dan

    2016-04-01

    The magnetic storm that commenced on June 22, 2015 was one of the largest storms in the current solar cycle. The availability of in situ observations from Magnetospheric Multiscale (MMS), the Van Allen Probes (VAP), and THEMIS in the magnetosphere, field-aligned currents from AMPERE, as well as the ionospheric data from the Floating Potential Measurement Unit (FPMU) instrument suite on board the International Space Station (ISS) represents an exciting opportunity to analyze storm-related dynamics. Our real-time space weather alert system sent out a "red alert" warning users of the event 2 hours in advance, correctly predicting Kp indices greater than 8. During this event, the MMS observatories were taking measurements in the magnetotail, VAP were in the inner magnetosphere, THEMIS was on the dayside, and the ISS was orbiting at 400 km every 90 minutes. Among the initial findings are the crossing of the dayside magnetopause into the region earthward of 8 RE, strong dipolarizations in the MMS magnetometer data, and dropouts in the particle fluxes seen by the MMS FPI instrument suite. At ionospheric altitudes, the FMPU measurements of the ion densities show dramatic post-sunset depletions at equatorial latitudes that are correlated with the particle flux dropouts measured by the MMS FPI. AMPERE data show highly variable currents varying from intervals of intense high latitude currents to currents at maximum polar cap expansion to 50 deg MLAT and exceeding 20 MA. In this paper, we use numerical simulations with global magnetohydrodynamic (MHD) models run at the CCMC and the Rice Convection Model (RCM) of the inner magnetosphere in an attempt to place the observations in the context of storm-time global electrodynamics and cross-check the simulation global Birkeland currents with AMPERE distributions. We present model-predicted effects of dipolarizations and the global convection on the inner magnetosphere via data-model comparison. We show comparisons of ion injections

  7. Environment and evolution of a cold-frontal mesoscale convective system

    NASA Technical Reports Server (NTRS)

    Trier, Stanley B.; Parsons, David B.; Clark, John H. E.

    1991-01-01

    Data obtained from the June 26-27, 1985 period of the Kansas-Oklahoma PRE-STORM field phase are employed to describe the evolution of a mesoscale convective system (MCS) responsible for a heavy rainfall event over a large portion of Oklahoma and Kansas. In the case examined, the eastward advancement of deep convection was aided by the formation of a series of nearly parallel rainbands before the main precipitation area. These rainbands, which developed in a field of boundary layer cloud streets, without the assistance of gust-front convergence, redefined the leading edge of the MCS and became the locus of the most intense convection in the precipitation system.

  8. Slowing the Summer Slide

    ERIC Educational Resources Information Center

    Smith, Lorna

    2012-01-01

    Research shows that summer slide--the loss of learning over the summer break--is a huge contributor to the achievement gap between low-income students and their higher-income peers. In fact, some researchers have concluded that two-thirds of the 9th-grade reading achievement gap can be explained by unequal access to summer learning opportunities…

  9. Summer Library Reading Programs

    ERIC Educational Resources Information Center

    Fiore, Carole D.

    2007-01-01

    Virtually all public libraries in the United States provide some type of summer library reading program during the traditional summer vacation period. Summer library reading programs provide opportunities for students of many ages and abilities to practice their reading skills and maintain skills that are developed during the school year. Fiore…

  10. Summer Television Project.

    ERIC Educational Resources Information Center

    Evansville-Vanderburgh School Corp., IN.

    Three general goals guided the creation of this summer education project: to maintain academic basic skills over the summer months, to involve parents in the learning process, and to involve teachers in reading inservice training. The summer television programs available to all Indiana children are "Ride the Reading Rocket" for grade 2; "Catch a…

  11. Booktalking: Avoiding Summer Drift

    ERIC Educational Resources Information Center

    Whittingham, Jeff; Rickman, Wendy A.

    2015-01-01

    Summer drift, otherwise known as loss of reading comprehension skills or reading achievement, has been a well-known and well-documented phenomenon of public education for decades. Studies from the late twentieth century to the present have demonstrated a slowdown in summer drift attributed to specific summer reading programs addressing motivation…

  12. Summer Correspondence Program.

    ERIC Educational Resources Information Center

    Sulphur Springs Union Elementary School District, Canyon Country, CA.

    THE FOLLOWING IS THE FULL TEXT OF THIS DOCUMENT: The goals of the Summer Correspondence Program have been to help students maintain their basic skills and avoid summer fall-out, as well as to promote parent involvement and positive community relations. After Proposition 13 left no funds for continuation of summer school programs, Sulphur Springs…

  13. Slithering into Summer

    ERIC Educational Resources Information Center

    Scott, Catherine; Matthews, Catherine

    2012-01-01

    The summer provides a unique opportunity for children to further their interests in science, especially science in the out-of-doors. Once school is out for the summer, there is seemingly unlimited time, with no strict curriculum guidelines to follow. For students with a passion for the out-of-doors, summer science camps and school-based summer…

  14. Summer Programs for Educators

    ERIC Educational Resources Information Center

    Curriculum Review, 2009

    2009-01-01

    There are so many great ways to extend oneself professionally--or personally--over the summer. This paper presents several opportunities for summer 2009: (1) The Teacher-to-Teacher Initiative; (2) Courage to Teach; (3) University of South Carolina's Summer Institute in Computer Science; (4) Online Program in Online Teaching; and (5) College Board…

  15. Inside storm window

    SciTech Connect

    Kaplan, J.I.

    1980-11-01

    The work effort to design, build, install, and evaluate an inside storm window is presented. The ISW, made of two separated layers of mylar (like a thermopane window) which when not in use can be rolled up in a shade, is described. The work effort included: development of a prototype model; the development of production facilities to turn out a small number (50) of ISW's; the production of the windows; the installation of the windows into buildings; the building of a test chamber to determine the R value of the ISW and the subsequent determination of the R value; and a survey to determine how the residents of the homes in which ISW's were installed felt about the windows. Comments on each of these tasks are presented and some comments on initial steps towards commercialization are offered. (MCW)

  16. ARkStorm: A West Coast Storm Scenario

    NASA Astrophysics Data System (ADS)

    Cox, D. A.; Jones, L. M.; Ralph, F. M.; Dettinger, M. D.; Porter, K.; Perry, S. C.; Barnard, P. L.; Hoover, D.; Wills, C. J.; Stock, J. D.; Croyle, W.; Ferris, J. C.; Plumlee, G. S.; Alpers, C. N.; Miller, M.; Wein, A.; Rose, A.; Done, J.; Topping, K.

    2009-12-01

    The United Stated Geological Survey (USGS) Multi-Hazards Demonstration Project (MHDP) is preparing a new emergency-preparedness scenario, called ARkStorm, to address massive U.S. West Coast storms analogous to those that devastated California in 1861-62. Storms of this magnitude are projected to become more frequent and intense as a result of climate change. The MHDP has assembled experts from the National Oceanic and Atmospheric Administration (NOAA), USGS, Scripps Institute of Oceanography, the State of California, California Geological Survey, the University of Colorado, the National Center for Atmospheric Research, and other organizations to design the large, but scientifically plausible, hypothetical scenario storm that would provide emergency responders, resource managers, and the public a realistic assessment of what is historically possible. The ARkStorm patterns the 1861 - 1862 historical events but uses modern modeling methods and data from large storms in 1969 and 1986. The ARkStorm draws heat and moisture from the tropical Pacific, forming Atmospheric Rivers (ARs) that grow in size, gain speed, and with a ferocity equal to hurricanes, slam into the U.S. West Coast for several weeks. Using sophisticated weather models and expert analysis, precipitation, snowlines, wind, and pressure data the modelers will characterize the resulting floods, landslides, and coastal erosion and inundation. These hazards will then be translated into the infrastructural, environmental, agricultural, social, and economic impacts. Consideration will be given to catastrophic disruptions to water supplies resulting from impacts on groundwater pumping, seawater intrusion, water supply degradation, and land subsidence. Possible climate-change forces that could exacerbate the problems will also be evaluated. In contrast to the recent U.S. East and Gulf Coast hurricanes, only recently have scientific and technological advances documented the ferocity and strength of possible future

  17. Investigating storm-time magnetospheric electrodynamics: Multi-spacecraft observations of the June 22, 2015 magnetic storm

    NASA Astrophysics Data System (ADS)

    Reiff, P. H.; Sazykin, S. Y.; Bala, R.; Coffey, V. N.; Chandler, M. O.; Minow, J. I.; Anderson, B. J.; Wolf, R.; Huba, J.; Baker, D. N.; Mauk, B.; Russell, C. T.

    2015-12-01

    The magnetic storm that commenced on June 22, 2015 was one of the largest storms in the current solar cycle. Availability of in situ observations from Magnetospheric Multiscale (MMS), the Van Allen Probes (VAP), and THEMIS in the magnetosphere, field-aligned currents from AMPERE, as well as the ionospheric data from the Floating Potential Measurement Unit (FPMU) instrument suite on board the International Space Station (ISS) represents an exciting opportunity to analyze storm-related dynamics. Our real-time space weather alert system sent out a "red alert" warning users of the event 2 hours in advance, correctly predicting Kp indices greater than 8. During this event, the MMS observatories were taking measurements in the magnetotail, VAP were in the inner magnetosphere, THEMIS was on the dayside, and the ISS was orbiting at 400 km every 90 minutes. Among the initial findings are the crossing of the dayside magnetopause into the region earthward of 8 RE, strong dipolarizations in the MMS magnetometer data, and dropouts in the particle fluxes seen by the MMS FPI instrument suite. At ionospheric altitudes, the FMPU measurements of the ion densities show dramatic post-sunset depletions at equatorial latitudes that are correlated with the particle flux dropouts measured by the MMS FPI. AMPERE data show highly variable currents varying from intervals of intense high latitude currents to currents at maximum polar cap expansion to 50 deg MLAT and exceeding 20 MA. In this paper, we use numerical simulations with global magnetohydrodynamic (MHD) models and the Rice Convection Model (RCM) of the inner magnetosphere in an attempt to place the observations in the context of storm-time global electrodynamics and cross-check the simulation global Birkeland currents with AMPERE distributions. Specifically, we will look at model-predicted effects of dipolarizations and the global convection on the inner magnetosphere via data-model comparison.

  18. Convective cloud top vertical velocity estimated from geostationary satellite rapid-scan measurements

    NASA Astrophysics Data System (ADS)

    Hamada, Atsushi; Takayabu, Yukari N.

    2016-05-01

    We demonstrate that the rate of development of cumulus clouds, as inferred from the so-called geostationary satellite "rapid-scan" measurements, is a good proxy for convective cloud top vertical velocity related to deep convective clouds. Convective cloud top vertical velocity is estimated from the decreasing rate of infrared brightness temperature observed by the Multi-functional Transport SATellite-1R (MTSAT-1R) over the ocean south of Japan during boreal summer. The frequency distribution of the estimated convective cloud top vertical velocity at each height is shown to distribute lognormally, and it is consistent with the statistical characteristics of direct measurements acquired in previous studies.

  19. Effect of convection on the summertime extratropical lower stratosphere

    NASA Astrophysics Data System (ADS)

    Dessler, A. E.; Sherwood, S. C.

    2004-12-01

    Satellite and in situ water vapor and ozone observations near the base of the overworld (θ ≈ 380-K potential temperature) are examined in summertime northern midlatitudes, with a focus on how their horizontal variations are influenced by deep convection. We show that summertime convection has a significant effect on the water vapor budget here, but only a small effect on the ozone budget. Using a simple model, we estimate that convection increases model extratropical water vapor at 380 K by 40% but decreases model extratropical ozone by only a few percent, relative to what would occur without convection. In situ data show that this convective injection occurs up to at least ˜390 K. This raises the possibility that the convectively moistened air might travel isentropically to the tropics and ascend into the stratospheric overworld without passing through the cold point. We argue that trends in convective moistening should be examined as possible contributors to observed trends in lower stratospheric water vapor, at least during summer months.

  20. On the contribution of plasma sheet bubbles to the storm time ring current

    NASA Astrophysics Data System (ADS)

    Yang, Jian; Toffoletto, Frank R.; Wolf, Richard A.; Sazykin, Stanislav

    2015-09-01

    Particle injections occur frequently inside 10 Re during geomagnetic storms. They are commonly associated with bursty bulk flows or plasma sheet bubbles transported from the tail to the inner magnetosphere. Although observations and theoretical arguments have suggested that they may have an important role in storm time dynamics, this assertion has not been addressed quantitatively. In this paper, we investigate which process is dominant for the storm time ring current buildup: large-scale enhanced convection or localized bubble injections. We use the Rice Convection Model-Equilibrium (RCM-E) to model a series of idealized storm main phases. The boundary conditions at 14-15 Re on the nightside are adjusted to randomly inject bubbles to a degree roughly consistent with observed statistical properties. A test particle tracing technique is then used to identify the source of the ring current plasma. We find that the contribution of plasma sheet bubbles to the ring current energy increases from ~20% for weak storms to ~50% for moderate storms and levels off at ~61% for intense storms, while the contribution of trapped particles decreases from ~60% for weak storms to ~30% for moderate and ~21% for intense storms. The contribution of nonbubble plasma sheet flux tubes remains ~20% on average regardless of the storm intensity. Consistent with previous RCM and RCM-E simulations, our results show that the mechanisms for plasma sheet bubbles enhancing the ring current energy are (1) the deep penetration of bubbles and (2) the bulk plasma pushed ahead of bubbles. Both the bubbles and the plasma pushed ahead typically contain larger distribution functions than those in the inner magnetosphere at quiet times. An integrated effect of those individual bubble injections is the gradual enhancement of the storm time ring current. We also make two predictions testable against observations. First, fluctuations over a time scale of 5-20 min in the plasma distributions and electric field

  1. Thromboembolic complications of thyroid storm

    PubMed Central

    Min, T; Benjamin, S; Cozma, L

    2014-01-01

    Summary Thyroid storm is a rare but potentially life-threatening complication of hyperthyroidism. Early recognition and prompt treatment are essential. Atrial fibrillation can occur in up to 40% of patients with thyroid storm. Studies have shown that hyperthyroidism increases the risk of thromboembolic events. There is no consensus with regard to the initiation of anticoagulation for atrial fibrillation in severe thyrotoxicosis. Anticoagulation is not routinely initiated if the risk is low on a CHADS2 score; however, this should be considered in patients with thyroid storm or severe thyrotoxicosis with impending storm irrespective of the CHADS2 risk, as it appears to increase the risk of thromboembolic episodes. Herein, we describe a case of thyroid storm complicated by massive pulmonary embolism. Learning points Diagnosis of thyroid storm is based on clinical findings. Early recognition and prompt treatment could lead to a favourable outcome.Hypercoagulable state is a recognised complication of thyrotoxicosis.Atrial fibrillation is strongly associated with hyperthyroidism and thyroid storm.Anticoagulation should be considered for patients with severe thyrotoxicosis and atrial fibrillation irrespective of the CHADS2 score.Patients with severe thyrotoxicosis and clinical evidence of thrombosis should be immediately anticoagulated until hyperthyroidism is under control. PMID:24683480

  2. Microphysics, Meteorology, Microwave and Modeling of Mediterranean Storms: The M(sup 5) Problem

    NASA Technical Reports Server (NTRS)

    Smith, Eric A.; Fiorino, Steven; Mugnai, Alberto; Panegrossi, Giulia; Tripoli, Gregory; Starr, David (Technical Monitor)

    2001-01-01

    Comprehensive understanding of the microphysical nature of Mediterranean storms requires a combination of in situ meteorological data analysis and radar-passive microwave data analysis, effectively integrated with numerical modeling studies at various scales, particularly from synoptic scale down to mesoscale. The microphysical properties of and their controls on severe storms are intrinsically related to meteorological processes under which storms have evolved, processes which eventually select and control the dominant microphysical properties themselves. Insofar as hazardous Mediterranean storms, highlighted by the September 25-28/1992 Genova flood event, the October 5-7/1998 Friuli flood event, and the October 13-15/2000 Piemonte flood event (all taking place in northern Italy), developing a comprehensive microphysical interpretation requires an understanding of the multiple phases of storm evolution and the heterogeneous nature of precipitation fields within the storm domains. This involves convective development, stratiform transition and decay, orographic lifting, and sloped frontal lifting proc esses. This also involves vertical motions and thermodynamical instabilities governing physical processes that determine details of the liquid/ice water contents, size distributions, and fall rates of the various modes of hydrometeors found within the storm environments. This paper presents detailed 4-dimensional analyses of the microphysical elements of the three severe Mediterranean storms identified above, investigated with the aid of SSM/I and TRMM satellite measurements (and other remote sensing measurements). The analyses are guided by nonhydrostatic mesoscale model simulations at high resolution of the intense rain producing portions of the storm environments. The results emphasize how meteorological controls taking place at the large scale, coupled with localized terrain controls, ultimately determine the most salient features of the bulk microphysical

  3. Effects of chemistry on convective and non-convective precipitation over North Eastern North America

    NASA Astrophysics Data System (ADS)

    Mashayekhi, R.; Sloan, J. J.

    2013-12-01

    The change in convective and non-convective (microphysically-induced) precipitation due to the influence of chemistry - and particularly that of anthropogenic aerosols - is investigated in this study. The overall effect of chemistry is deduced from a comparison of the results from the Weather Research and Forecasting (WRF v3.4) model and its corresponding chemistry version (WRF/Chem v3.4). Simulations are conducted for a five-month period from April to August 2009 in a domain covering North Eastern North America with 12 km grid spacing. We created the temporally and spatially distributed anthropogenic emissions from area, point and mobile sources using the Sparse Matrix Operator Kernel Emissions (SMOKE v2.7) modeling system by processing the total annual county or province-based inventories for the U.S. and Canada using the appropriate temporal, chemical speciation and spatial surrogate cross-reference files. This study shows that convective precipitation dominates in the summer and in the southern part of the domain due to greater tropospheric instability in warmer periods. Non-convective precipitation becomes more significant during the spring, but it contributes much less in total rain. Both WRF and WRF/Chem models overpredict the mean total daily precipitation, with a positive bias that increases as the convective precipitation increases in warmer months. This appears to be a common problem with the prediction of convective precipitation; it is associated with its high spatial variability. The comparison of WRF/Chem results with those of WRF shows that a non-negligible change in both convective and cloud-resolved (non-convective) precipitation is caused by chemistry (including aerosols) over most parts of the domain. These changes can be attributed to both radiative and microphysical causes. A chemistry-induced change of approximately 15% is found in the five-month mean daily convective precipitation over areas with high convective rain. This can be traced to

  4. Observations of aerosol-induced convective invigoration in the tropical east Atlantic

    NASA Astrophysics Data System (ADS)

    Storer, R. L.; Heever, S. C.; L'Ecuyer, T. S.

    2014-04-01

    Four years of CloudSat data have been analyzed over a region of the east Atlantic Ocean in order to examine the influence of aerosols on deep convection. The satellite data were combined with information about aerosols taken from the Global and Regional Earth-System Monitoring Using Satellite and In Situ Data model. Only those profiles fitting the definition of deep convective clouds were analyzed. Overall, the cloud center of gravity, cloud top, and rain top were all found to increase with increased aerosol loading. These effects were largely independent of the environment, and the differences between the cleanest and most polluted clouds sampled were found to be statistically significant. When examining an even smaller subset of deep convective clouds likely to be part of the convective core, similar trends were seen. These observations suggest that convective invigoration occurs with increased aerosol loading, leading to deeper, stronger storms in polluted environments.

  5. Characteristics of ionospheric storms in East Asia during 2002-2014

    NASA Astrophysics Data System (ADS)

    Wang, Xiao; Zherebtsov, Gelii; Wang, Guojun; Ratovsky, Konstantin; Romanova, Elena; Shi, Jiankui

    2016-07-01

    The ionosphere experiences intense response during the geomagnetic storm and it varies with latitude and longitude. The DPS-4 digisonde measurements and GPS-TEC data of ionospheric stations located at different latitudes in the longitudinal sector of 90-130°E during 2002 to 2014 were analyzed to investigate the ionospheric effects in the different latitude of East Asia during geomagnetic storm. About 80 geomagnetic storms are selected according to the Dst index and observed data and they are in different seasons and different solar activity levels. A few quiet days' averages of data before geomagnetic storm were used as the undisturbed level. Results show that for the middle and high latitude, the short-lived positive disturbance associated with the initial phase of the every storm was observed in each season and then the disturbances were negative till the termination of storm. At the low latitude, storm-time disturbances of foF2 have obvious diurnal, seasonal and solar cycle characteristics. Generally, geomagnetic activity will cause foF2 to increase at daytime and decrease at nighttime except for the summer in low solar activity period. The intensity of response of foF2 is stronger at nighttime than that at daytime. The negative ionospheric storm effect is the strongest in summer and the positive ionospheric storm effect is the strongest in winter. In high solar activity period, the diurnal variation of the response of foF2 is very pronounced in each season, and the strong ionospheric response can last several days. In low solar activity period, ionospheric response has very pronounced diurnal variation in winter only. It's notable that geomagnetic activities occurred at local time nighttime can cause stronger and longer responses of foF2 at the low latitude. For the TEC data, strong disturbances can be observed simultaneously from high latitude to low latitude during the main phase of some storms. Generally strong/weak storms can cause the negative

  6. Solar System dynamics and global-scale dust storms on Mars

    NASA Astrophysics Data System (ADS)

    Shirley, James H.

    2015-05-01

    Global-scale dust storms occur during the southern summer season on Mars in some Mars years but not in others. We present an updated catalog of Mars years including such storms (n = 9) and Mars years without global-scale storms (n = 11) through the year 2013. A remarkable relationship links the occurrence and non-occurrence of global-scale dust storms on Mars with changes in the orbital angular momentum of Mars with respect to the Solar System barycenter (LMars). All of the global-scale dust storms became planet-encircling in both latitude and longitude during periods when LMars was increasing or near maxima. Statistical significance at the 1% level is obtained for the clustering tendency of LMars phases for the 5 mid-season storms with Ls ranging from 208° to 262° (1956, 1971, 1982, 1994, and 2007). The 11 Mars years without global-scale dust storms exhibit mainly decreasing and minimum values of LMars during the first half of the dust storm season; this tendency is statistically significant at the 5% level. A systematic progression is present in the phasing of the solar irradiance and LMars waveforms for the global-scale storm years. LMars phases for the early season global-scale storms of 1977 and 2001 are advanced in phase with respect to those of the mid-season storms, while the phase for the late season storm of 1973 is delayed with respect to those of the mid-season storms cluster. Factors internal to the Mars climate system, such as a spatial redistribution of surface dust from year to year, must be invoked to account for the non-occurrence of global-scale dust storms in five years (1986, 2003, 2005, 2009, and 2013) when the LMars phase was otherwise favorable. Our results suggest that the occurrence of increasing or peak values of LMars immediately prior to and during the Mars dust storm season may be a necessary-but-not-sufficient condition for the initiation of global-scale dust storms on Mars.

  7. Centralized Storm Information System (CSIS)

    NASA Technical Reports Server (NTRS)

    Norton, C. C.

    1985-01-01

    A final progress report is presented on the Centralized Storm Information System (CSIS). The primary purpose of the CSIS is to demonstrate and evaluate real time interactive computerized data collection, interpretation and display techniques as applied to severe weather forecasting. CSIS objectives pertaining to improved severe storm forecasting and warning systems are outlined. The positive impact that CSIS has had on the National Severe Storms Forecast Center (NSSFC) is discussed. The benefits of interactive processing systems on the forecasting ability of the NSSFC are described.

  8. Deep winds beneath Saturn's upper clouds from a seasonal long-lived planetary-scale storm.

    PubMed

    Sánchez-Lavega, A; del Río-Gaztelurrutia, T; Hueso, R; Gómez-Forrellad, J M; Sanz-Requena, J F; Legarreta, J; García-Melendo, E; Colas, F; Lecacheux, J; Fletcher, L N; Barrado-Navascués, D; Parker, D

    2011-07-01

    Convective storms occur regularly in Saturn's atmosphere. Huge storms known as Great White Spots, which are ten times larger than the regular storms, are rarer and occur about once per Saturnian year (29.5 Earth years). Current models propose that the outbreak of a Great White Spot is due to moist convection induced by water. However, the generation of the global disturbance and its effect on Saturn's permanent winds have hitherto been unconstrained by data, because there was insufficient spatial resolution and temporal sampling to infer the dynamics of Saturn's weather layer (the layer in the troposphere where the cloud forms). Theoretically, it has been suggested that this phenomenon is seasonally controlled. Here we report observations of a storm at northern latitudes in the peak of a weak westward jet during the beginning of northern springtime, in accord with the seasonal cycle but earlier than expected. The storm head moved faster than the jet, was active during the two-month observation period, and triggered a planetary-scale disturbance that circled Saturn but did not significantly alter the ambient zonal winds. Numerical simulations of the phenomenon show that, as on Jupiter, Saturn's winds extend without decay deep down into the weather layer, at least to the water-cloud base at pressures of 10-12 bar, which is much deeper than solar radiation penetrates.

  9. Severe storm identification with satellite microwave radiometry: An initial investigation with Nimbus-7 SMMR data

    NASA Technical Reports Server (NTRS)

    Spencer, R. W.; Howland, M. R.

    1984-01-01

    The severe weather characteristics of convective storms as observed by the Nimbus 7 Scanning Multichannel Microwave Radiometer (SMMR) are investigated. Low 37 GHz brightness temperatures (due to scattering of upwelling radiation by precipitation size ice) are related to the occurrence of severe weather (large hail, strong winds or wind damage, tornadoes and funnel clouds) within one hour of the satellite observation time. During 1979 and 1980 over the United States there were 263 storms which had very cold 37 GHz signatures. Of these storms 15% were severe. The SMMR detected hail, wind, and tornadic storms equally well. Critical Success Indices (CSI's) of 0.32, 0.48, and 0.38 are achieved for the thresholding of severe vs. nonsevere low brightness temperature events during 1979, 1980, and the two years combined, respectively. Such scores are comparable to skill scores for early radar detection methods. These results suggest that a future geostationary passive microwave imaging capability at 37 GHz, with sufficient spatial and temporal resolution, would allow the detection of severe convective storms. This capability would provide a useful complement to radar, especially in areas not covered by radar.

  10. Deep winds beneath Saturn's upper clouds from a seasonal long-lived planetary-scale storm.

    PubMed

    Sánchez-Lavega, A; del Río-Gaztelurrutia, T; Hueso, R; Gómez-Forrellad, J M; Sanz-Requena, J F; Legarreta, J; García-Melendo, E; Colas, F; Lecacheux, J; Fletcher, L N; Barrado-Navascués, D; Parker, D

    2011-07-01

    Convective storms occur regularly in Saturn's atmosphere. Huge storms known as Great White Spots, which are ten times larger than the regular storms, are rarer and occur about once per Saturnian year (29.5 Earth years). Current models propose that the outbreak of a Great White Spot is due to moist convection induced by water. However, the generation of the global disturbance and its effect on Saturn's permanent winds have hitherto been unconstrained by data, because there was insufficient spatial resolution and temporal sampling to infer the dynamics of Saturn's weather layer (the layer in the troposphere where the cloud forms). Theoretically, it has been suggested that this phenomenon is seasonally controlled. Here we report observations of a storm at northern latitudes in the peak of a weak westward jet during the beginning of northern springtime, in accord with the seasonal cycle but earlier than expected. The storm head moved faster than the jet, was active during the two-month observation period, and triggered a planetary-scale disturbance that circled Saturn but did not significantly alter the ambient zonal winds. Numerical simulations of the phenomenon show that, as on Jupiter, Saturn's winds extend without decay deep down into the weather layer, at least to the water-cloud base at pressures of 10-12 bar, which is much deeper than solar radiation penetrates. PMID:21734704

  11. Latitudinal and Seasonal Investigations of Storm-Time TEC Variation

    NASA Astrophysics Data System (ADS)

    Adimula, I. A.; Oladipo, O. A.; Adebiyi, S. J.

    2016-07-01

    The ionosphere responds markedly and unpredictably to varying magnetospheric energy inputs caused by solar disturbances on the geospace. Knowledge of the impact of the space weather events on the ionosphere is important to assess the environmental effect on the operations of ground- and space-based technologies. Thus, global positioning system (GPS) measurements from the international GNSS service (IGS) database were used to investigate the ionospheric response to 56 geomagnetic storm events at six different latitudes comprising the northern and southern hemispheres in the Afro-European sector. Statistical distributions of total electron content (TEC) response show that during the main phase of the storms, enhancement of TEC is more pronounced in most of the seasons, regardless of the latitude and hemisphere. However, a strong seasonal dependence appears in the TEC response during the recovery phase. Depletion of TEC is majorly observed at the high latitude stations, and its appearance at lower latitudes is seasonally dependent. In summer hemisphere, the depletion of TEC is more pronounced in nearly all the latitudinal bands. In winter hemisphere, enhancement as well as depletion of TEC is observed over the high latitude, while enhancement is majorly observed over the mid and low latitudes. In equinoxes, the storm-time TEC distribution shows a fairly consistent characteristic with the summer distribution, particularly in the northern hemisphere.

  12. Supergranulation, a convective phenomenon

    NASA Astrophysics Data System (ADS)

    Udayashankar, Paniveni

    2015-08-01

    Observation of the Solar photosphere through high resolution instruments have long indicated that the surface of the Sun is not a tranquil, featureless surface but is beset with a granular appearance. These cellular velocity patterns are a visible manifestation of sub- photospheric convection currents which contribute substantially to the outward transport of energy from the deeper layers, thus maintaining the energy balance of the Sun as a whole.Convection is the chief mode of transport in the outer layers of all cool stars such as the Sun (Noyes,1982). Convection zone of thickness 30% of the Solar radius lies in the sub-photospheric layers of the Sun. Convection is revealed on four scales. On the scale of 1000 km, it is granulation and on the scale of 8-10 arcsec, it is Mesogranulation. The next hierarchial scale of convection ,Supergranules are in the range of 30-40 arcsec. The largest reported manifestation of convection in the Sun are ‘Giant Cells’or ‘Giant Granules’, on a typical length scale of about 108 m.'Supergranules' is caused by the turbulence that extends deep into the convection zone. They have a typical lifetime of about 20hr with spicules marking their boundaries. Gas rises in the centre of the supergranules and then spreads out towards the boundary and descends.Broadly speaking supergranules are characterized by the three parameters namely the length L, the lifetime T and the horizontal flow velocity vh . The interrelationships amongst these parameters can shed light on the underlying convective processes and are in agreement with the Kolmogorov theory of turbulence as applied to large scale solar convection (Krishan et al .2002 ; Paniveni et. al. 2004, 2005, 2010).References:1) Noyes, R.W., The Sun, Our Star (Harvard University Press, 1982)2) Krishan, V., Paniveni U., Singh , J., Srikanth R., 2002, MNRAS, 334/1,2303) Paniveni , U., Krishan, V., Singh, J., Srikanth, R., 2004, MNRAS, 347, 1279-12814) Paniveni , U., Krishan, V., Singh, J

  13. Anomalously weak solar convection.

    PubMed

    Hanasoge, Shravan M; Duvall, Thomas L; Sreenivasan, Katepalli R

    2012-07-24

    Convection in the solar interior is thought to comprise structures on a spectrum of scales. This conclusion emerges from phenomenological studies and numerical simulations, though neither covers the proper range of dynamical parameters of solar convection. Here, we analyze observations of the wavefield in the solar photosphere using techniques of time-distance helioseismology to image flows in the solar interior. We downsample and synthesize 900 billion wavefield observations to produce 3 billion cross-correlations, which we average and fit, measuring 5 million wave travel times. Using these travel times, we deduce the underlying flow systems and study their statistics to bound convective velocity magnitudes in the solar interior, as a function of depth and spherical-harmonic degree ℓ. Within the wavenumber band ℓ < 60, convective velocities are 20-100 times weaker than current theoretical estimates. This constraint suggests the prevalence of a different paradigm of turbulence from that predicted by existing models, prompting the question: what mechanism transports the heat flux of a solar luminosity outwards? Advection is dominated by Coriolis forces for wavenumbers ℓ < 60, with Rossby numbers smaller than approximately 10(-2) at r/R([symbol: see text]) = 0.96, suggesting that the Sun may be a much faster rotator than previously thought, and that large-scale convection may be quasi-geostrophic. The fact that isorotation contours in the Sun are not coaligned with the axis of rotation suggests the presence of a latitudinal entropy gradient.

  14. Anomalously Weak Solar Convection

    NASA Technical Reports Server (NTRS)

    Hanasoge, Shravan M.; Duvall, Thomas L.; Sreenivasan, Katepalli R.

    2012-01-01

    Convection in the solar interior is thought to comprise structures on a spectrum of scales. This conclusion emerges from phenomenological studies and numerical simulations, though neither covers the proper range of dynamical parameters of solar convection. Here, we analyze observations of the wavefield in the solar photosphere using techniques of time-distance helioseismology to image flows in the solar interior. We downsample and synthesize 900 billion wavefield observations to produce 3 billion cross-correlations, which we average and fit, measuring 5 million wave travel times. Using these travel times, we deduce the underlying flow systems and study their statistics to bound convective velocity magnitudes in the solar interior, as a function of depth and spherical- harmonic degree l..Within the wavenumber band l < 60, convective velocities are 20-100 times weaker than current theoretical estimates. This constraint suggests the prevalence of a different paradigm of turbulence from that predicted by existing models, prompting the question: what mechanism transports the heat flux of a solar luminosity outwards? Advection is dominated by Coriolis forces for wavenumbers l < 60, with Rossby numbers smaller than approximately 10(exp -2) at r/R-solar = 0.96, suggesting that the Sun may be a much faster rotator than previously thought, and that large-scale convection may be quasi-geostrophic. The fact that isorotation contours in the Sun are not coaligned with the axis of rotation suggests the presence of a latitudinal entropy gradient.

  15. Neonatal thyroid storm accompanied with severe anaemia.

    PubMed

    Cao, Lu-Ying; Wei, Hong; Wang, Zheng-Li

    2015-07-01

    Neonatal thyroid storm is rare; the diagnostic criteria and management of neonatal thyroid storm have not been well established. In this paper, we report a preterm infant diagnosed with neonatal hyperthyroidism secondary to maternal Graves' disease who was discharged after therapy. Unfortunately, he was rehospitalised for neonatal thyroid storm. We will discuss the diagnosis and general therapy of neonatal thyroid storm.

  16. The Radiation Belt Storm Probes

    NASA Video Gallery

    The Radiation Belt Storm Probe mission (RBSP) will explore the Van Allen Radiation Belts in the Earth's magnetosphere. The charge particles in these regions can be hazardous to both spacecraft and ...

  17. Cocaine Intoxication and Thyroid Storm

    PubMed Central

    Lacy, Mary E.

    2014-01-01

    Introduction. Cocaine, a widely used sympathomimetic drug, causes thermoregulatory and cardiac manifestations that can mimic a life-threatening thyroid storm. Case. A man presented to the emergency department requesting only cocaine detoxification. He reported symptoms over the last few years including weight loss and diarrhea, which he attributed to ongoing cocaine use. On presentation he had an elevated temperature of 39.4°C and a heart rate up to 130 beats per minute. Examination revealed the presence of an enlarged, nontender goiter with bilateral continuous bruits. He was found to have thyrotoxicosis by labs and was treated for thyroid storm and cocaine intoxication concurrently. The patient was ultimately diagnosed with Graves’ disease and treated with iodine-131 therapy. Conclusion. Cocaine use should be considered a possible trigger for thyroid storm. Recognition of thyroid storm is critical because of the necessity for targeted therapy and the significant mortality associated with the condition if left untreated. PMID:26425625

  18. Tropical Storm Faxai's Rainfall Rates

    NASA Video Gallery

    This animation shows Tropical Storm Faxai's rainfall rates on March 2 from a TRMM TMI/PR rainfall analysis being faded in over infrared cloud data from the TRMM VIRS instrument. Credit: SSAI/NASA, ...

  19. Cloudsat Dissects Tropical Storm Ileana

    NASA Video Gallery

    NASA's CloudSat satellite's Cloud Profiling Radar captured a sideways look across Tropical Storm Ileana on Aug. 27 at 20:40 UTC. The colors indicate intensity of reflected radar energy. The blue ar...

  20. Atmospheric inputs of organic matter to a forested watershed: Variations from storm to storm over the seasons

    USGS Publications Warehouse

    Iavorivska , Lidiia; Boyer, Elizabeth W.; Miller, Matthew P.; Brown, Michael G.; Vasilopoulos , Terrie; Fuentes, Jose D.; Duffy, Christopher J.

    2016-01-01

    The objectives of this study were to determine the quantity and chemical composition of precipitation inputs of dissolved organic carbon (DOC) to a forested watershed; and to characterize the associated temporal variability. We sampled most precipitation that occurred from May 2012 through August 2013 at the Susquehanna Shale Hills Critical Zone Observatory (Pennsylvania, USA). Sub-event precipitation samples (159) were collected sequentially during 90 events; covering various types of synoptic meteorological conditions in all climatic seasons. Precipitation DOC concentrations and rates of wet atmospheric DOC deposition were highly variable from storm to storm, ranging from 0.3 to 5.6 mg C L−1 and from 0.5 to 32.8 mg C m−2 h−1, respectively. Seasonally, storms in spring and summer had higher concentrations of DOC and more optically active organic matter than in winter. Higher DOC concentrations resulted from weather types that favor air advection, where cold frontal systems, on average, delivered more than warm/stationary fronts and northeasters. A mixed modeling statistical approach revealed that factors related to storm properties, emission sources, and to the chemical composition of the atmosphere could explain more than 60% of the storm to storm variability in DOC concentrations. This study provided observations on changes in dissolved organic matter that can be useful in modeling of atmospheric oxidative chemistry, exploring relationships between organics and other elements of precipitation chemistry, and in considering temporal changes in ecosystem nutrient balances and microbial activity.

  1. Riding the storm out

    NASA Astrophysics Data System (ADS)

    Wurman, Josh

    2009-04-01

    I am standing on a bridge near the North Carolina coast. There is a light breeze, and I am enjoying some hazy sunshine. But this calm is an illusion: in a few minutes winds of up to 45ms-1 (100 mph) will sweep in again. The approaches to my section of the bridge are already drowned under 2.5 m of water, and my companions on this island are an eclectic mix of traumatized animals, including snakes, rats, wounded pelicans and frogs. Earlier, one of the snakes flew through the air past my truck. The animals and I have been drawn to this bridge by Hurricane Isabel, which has just slammed into the coastal islands of North Carolina, and at the moment we are in the calm, sunny eye of the storm. The animals are just trying to survive on the area's only dry ground. But I have come to the bridge with a radar system on a truck and have spent a night and a day on it because I want to know what is happening inside this hurricane.

  2. Weak Linkage between the Heaviest Rainfall and Tallest Storms

    NASA Astrophysics Data System (ADS)

    Hamada, A.; Takayabu, Y. N.; Liu, C.; Zipser, E. J.

    2015-12-01

    Eleven years measurements from the Precipitation Radar (PR) onboard the Tropical Rainfall Measuring Mission (TRMM) satellite reveals robust differences in rainfall characteristics between extreme rainfall and convection events, irrespective of region. After accumulating `rainfall events' defined as a set of contiguous rainy pixels of TRMM PR measurements for each 2.5 x 2.5 degree grid cell, three different types of regional extreme rainfall events are defined in each grid cell, using the maximum values of near-surface rainfall rate (NSR) and 40-dBZ echo top height (ETH40) in rainfall events; R-only (H-only) extreme events are defined as rainfall events of which the maximum NSR (ETH40) is within top 0.1% but the ETH40 (NSR) is not; RH extreme events are defined as those of which both the maxima of NSR and ETH40 are within top 0.1%. Only a small fraction of rainfall extreme events are found to be related to convective extremes. The results demonstrate that, even in regions where severe convective storms are representative extreme weather events, the heaviest rainfall events are mostly associated with less intense convection. There are robust differences in echo profiles, rainfall characteristics, and local environments between extreme rainfall and convection events, irrespective of region. Extreme rainfall events exhibit lower echo-top height and downward increase of radar reflectivity (Ze) below the freezing level, whereas extreme convection events exhibit more vertically aligned echo structure. The echo and environmental characteristics of extreme rainfall events imply the importance of warm-rain processes in producing extreme rainfall. An important concern regarding the PR measurements in Ku band is significant attenuation by severe hailstorms. We performed a statistical evaluation of the PR measurements using 5-yr measurements obtained during the Baiu season (May-June) using a ground-based C-band radar in Okinawa, Japan, and confirmed that the attenuation

  3. Identifying Landscape Areas Prone to Generating Storm Runoff in Central New York Agricultural Fields

    NASA Astrophysics Data System (ADS)

    Hofmeister, K.; Walter, M. T.

    2015-12-01

    Nonpoint source (NPS) pollution continues to be a leading cause of surface water degradation, especially in agricultural areas. In humid regions where variable source area (VSA) hydrology dominates storm runoff, NPS pollution is generated where VSAs coincide with polluting activities. Mapping storm runoff risks could allow for more precise and informed targeting of NPS pollution mitigation practices in agricultural landscapes. Topographic wetness indices (TWI) provide good approximations of relative soil moisture patterns and relative storm runoff risks. Simulation models are typically used in conjunction with TWIs to quantify VSA behavior. In this study we use empirically derived relationships between TWI values, volumetric water content (VWC) and rainfall frequencies to develop runoff probability maps. Rainfall and soil VWC were measured across regionally representative agricultural areas in central New York over three years (2012-2015) to determine the volume of runoff generated from agricultural fields in the area. We assumed the threshold for storm runoff occurs when the combination of antecedent soil water and rainfall are sufficient to saturate the soil. We determined that approximately 50% of the storm runoff volume is generated from 10% of the land area during spring, summer, and autumn seasons, while the risk of storm runoff generation is higher in the spring and autumn seasons than in the summer for the same area of land.

  4. Ionospheric redistribution during geomagnetic storms

    PubMed Central

    Immel, T J; Mannucci, A J

    2013-01-01

    [1]The abundance of plasma in the daytime ionosphere is often seen to grow greatly during geomagnetic storms. Recent reports suggest that the magnitude of the plasma density enhancement depends on the UT of storm onset. This possibility is investigated over a 7year period using global maps of ionospheric total electron content (TEC) produced at the Jet Propulsion Laboratory. The analysis confirms that the American sector exhibits, on average, larger storm time enhancement in ionospheric plasma content, up to 50% in the afternoon middle-latitude region and 30% in the vicinity of the high-latitude auroral cusp, with largest effect in the Southern Hemisphere. We investigate whether this effect is related to the magnitude of the causative magnetic storms. Using the same advanced Dst index employed to sort the TEC maps into quiet and active (Dst<−100 nT) sets, we find variation in storm strength that corresponds closely to the TEC variation but follows it by 3–6h. For this and other reasons detailed in this report, we conclude that the UT-dependent peak in storm time TEC is likely not related to the magnitude of external storm time forcing but more likely attributable to phenomena such as the low magnetic field in the South American region. The large Dst variation suggests a possible system-level effect of the observed variation in ionospheric storm response on the measured strength of the terrestrial ring current, possibly connected through UT-dependent modulation of ion outflow. PMID:26167429

  5. Magnetic storms and induction hazards

    USGS Publications Warehouse

    Love, Jeffrey J.; Rigler, E. Joshua; Pulkkinen, Antti; Balch, Christopher

    2014-01-01

    Magnetic storms are potentially hazardous to the activities and technological infrastructure of modern civilization. This reality was dramatically demonstrated during the great magnetic storm of March 1989, when surface geoelectric fields, produced by the interaction of the time-varying geomagnetic field with the Earth's electrically conducting interior, coupled onto the overlying Hydro-Québec electric power grid in Canada. Protective relays were tripped, the grid collapsed, and about 9 million people were temporarily left without electricity [Bolduc, 2002].

  6. Storm Surge Climatology of the Arctic Marginal Seas

    NASA Astrophysics Data System (ADS)

    Proshutinsky, T.; Proshutinsky, A.; Maslanik, J.; Solomon, S.; Ashik, I.

    2002-12-01

    The shore of the arctic seas are generally of low relief and the combination of waves and high water levels during late summer and fall storms before the development of significant sea-ice cover can be particularly damaging to shorelines. Gravel barrier beaches can be overwashed and eroded while bluffs consisting of unlithified ice-bonded sediment and segregated ice can fail and retreat. Storm surge climatology of the arctic marginal seas is investigated based on observational data and 2-D coupled ice-ocean barotropic model results. Meteorological forcing is calculated based on NCAR/NCEP reanalysis data for 1948-present period. The spatial resolution of the model is 13.89 km. The sea ice conditions (concentration and thickness) are prescribed on the mean monthly basis. The model was calibrated based on the strongest storm surges observed in the Kara, Laptev, East-Siberian, Chukchi and Beaufort Seas. Simulation results are in relatively good agreement with observations of sea level heights and ice drift. Detailed studies showed that the spatial and temporal resolutions of the NCEP/NCAR sea level pressure data (2.5x2.5 degree, 6 hours) are too low and can not reproduce well extreme conditions typical for the relatively small polar cyclones but storm surge event frequency is reproduce very well. The results of this study can be used to aid current and future scenario risk assessments of coastal flooding and costal erosion rates.

  7. The Role of Gravity Waves from Severe US Convection in Driving the Brewer-Dobson Circulation Using a Model with Realistic Thermodynamic Sources

    NASA Astrophysics Data System (ADS)

    Stephan, C. C.; Alexander, M. J.

    2015-12-01

    An inter-model comparison of the annual-mean upward mass flux at 70 hPa in comprehensive chemistry-climate models shows reasonably good agreement on the total strength of the Brewer-Dobson circulation (BDC) and its trend in the 21st century, but there is large variability in terms of the relative contributions by parameterized gravity waves (GWs) versus resolved Rossby waves. This model dependency presents a major weakness in our current understanding of the BDC and can partly be attributed to deficiencies in non-orographic GW drag parameterizations. We quantify the contribution of small-scale GWs from summer US storm systems to the BDC using a high-resolution, GW-resolving modeling approach. A nonlinear idealized dry version of the WRF model is forced with high-resolution latent heating/cooling derived from precipitation observations. For several case studies, it is shown that this model produces an excellent quantitative comparison to waves observed by satellite and captures the intermittency associated with convective sources of strong GW events. We model the entire month of June 2014 over the continental US. The contribution of GWs from summer US storm systems to the BDC is quantified and compared to MERRA reanalysis data and the CAM5 model. Non-orographic GW drag parameterizations used in large-scale models are poorly constrained by observational validation and commonly have tuning parameters with large uncertainties. In particular, capturing the high intermittency of the GW field presents an ongoing important challenge, as a given averaged momentum flux carried by a large number of small-amplitude GWs will produce a drag at much higher altitudes than that produced by the same averaged flux carried by a small number of high-amplitude GWs. In studying the relationship between precipitation strength, GW momentum flux amplitude and magnitude of the stratospheric GW drag, we highlight the potential for improving gravity wave drag parameterizations in global models.

  8. Active control of convection

    SciTech Connect

    Bau, H.H.

    1995-12-31

    Using stability theory, numerical simulations, and in some instances experiments, it is demonstrated that the critical Rayleigh number for the bifurcation (1) from the no-motion (conduction) state to the motion state and (2) from time-independent convection to time-dependent, oscillatory convection in the thermal convection loop and Rayleigh-Benard problems can be significantly increased or decreased. This is accomplished through the use of a feedback controller effectuating small perturbations in the boundary data. The controller consists of sensors which detect deviations in the fluid`s temperature from the motionless, conductive values and then direct actuators to respond to these deviations in such a way as to suppress the naturally occurring flow instabilities. Actuators which modify the boundary`s temperature/heat flux are considered. The feedback controller can also be used to control flow patterns and generate complex dynamic behavior at relatively low Rayleigh numbers.

  9. Direct Measurements of the Convective Recycling of the Upper Troposphere

    NASA Technical Reports Server (NTRS)

    Bertram, Timothy H.; Perring, Anne E.; Wooldridge, Paul J.; Crounse, John D.; Kwan, Alan J.; Wennberg, Paul O.; Scheuer, Eric; Dibb, Jack; Avery, Melody; Sachse, Glen; Vay, Stephanie A.; Crawford, James H.; McNaughton, Cameron S.; Clarke, Antony; Pickering, Kenneth E.; Fuelberg, Henry; Huey, Greg; Blake, Donald R.; Singh, Hanwant B.; Hall, Samuel R.; Shetter, Richard E.; Fried, Alan; Heikes, Brian G.; Cohen, Ronald C.

    2007-01-01

    We present a statistical representation of the aggregate effects of deep convection on the chemistry and dynamics of the Upper Troposphere (UT) based on direct aircraft observations of the chemical composition of the UT over the Eastern United States and Canada during summer. These measurements provide new and unique observational constraints on the chemistry occurring downwind of convection and the rate at which air in the UT is recycled, previously only the province of model analyses. These results provide quantitative measures that can be used to evaluate global climate and chemistry models.

  10. An Evaluation of Lightning Flash Rate Parameterizations Based on Observations of Colorado Storms during DC3

    NASA Astrophysics Data System (ADS)

    Basarab, B.; Fuchs, B.; Rutledge, S. A.

    2013-12-01

    Predicting lightning activity in thunderstorms is important in order to accurately quantify the production of nitrogen oxides (NOx = NO + NO2) by lightning (LNOx). Lightning is an important global source of NOx, and since NOx is a chemical precursor to ozone, the climatological impacts of LNOx could be significant. Many cloud-resolving models rely on parameterizations to predict lightning and LNOx since the processes leading to charge separation and lightning discharge are not yet fully understood. This study evaluates predicted flash rates based on existing lightning parameterizations against flash rates observed for Colorado storms during the Deep Convective Clouds and Chemistry Experiment (DC3). Evaluating lightning parameterizations against storm observations is a useful way to possibly improve the prediction of flash rates and LNOx in models. Additionally, since convective storms that form in the eastern plains of Colorado can be different thermodynamically and electrically from storms in other regions, it is useful to test existing parameterizations against observations from these storms. We present an analysis of the dynamics, microphysics, and lightning characteristics of two case studies, severe storms that developed on 6 and 7 June 2012. This analysis includes dual-Doppler derived horizontal and vertical velocities, a hydrometeor identification based on polarimetric radar variables using the CSU-CHILL radar, and insight into the charge structure using observations from the northern Colorado Lightning Mapping Array (LMA). Flash rates were inferred from the LMA data using a flash counting algorithm. We have calculated various microphysical and dynamical parameters for these storms that have been used in empirical flash rate parameterizations. In particular, maximum vertical velocity has been used to predict flash rates in some cloud-resolving chemistry simulations. We diagnose flash rates for the 6 and 7 June storms using this parameterization and compare

  11. Severe Weather Research at the European Severe Storms Laboratory

    NASA Astrophysics Data System (ADS)

    Groenemeijer, Pieter

    2013-04-01

    The European Severe Storms Laboratory's (ESSL) aim is to increase understanding of high-impact weather, with a particular focus on phenomena with small spatial and temporal dimensions, such as large hail, convectively-driven severe wind gusts, tornadoes and extreme precipitation.The ESSL performs and supports research activities and contributes to enhancing forecasting and warning capabilities in several ways. First, ESSL supports research by providing quality-controlled point data on severe weather events in the European Severe Weather Database. These data are collected through collaborations with networks of voluntary observers, and National HydroMeteorological Institutes throughout Europe. Second, research carried out at ESSL includes modelling the present and future occurrence of severe weather phenomena. This is done by developing proxies for severe weather events for use with reanalysis and climate model data. Third, at the ESSL Testbed, new products to support forecasting and warning operations are tested and demonstrated. Among these tools are visualizations of NWP ensemble data as well as radar, satellite and lightning detection data. Testbed participants provide feedback to the products and receive training in forecasting severe convective weather. Last, every second year ESSL organizes or co-organizes the European Conferences on Severe Storms.

  12. Summer library reading programs.

    PubMed

    Fiore, Carole D

    2007-01-01

    Virtually all public libraries in the United States provide some type of summer library reading program during the traditional summer vacation period. Summer library reading programs provide opportunities for students of many ages and abilities to practice their reading skills and maintain skills that are developed during the school year. Fiore summarizes some of the research in the field and relates it to library programs and usage by students. Several traditional and innovative programs from U.S. and Canadian libraries are described. She concludes with a call for further research related to summer library reading programs.

  13. Evidence for potential and inductive convection during intense geomagnetic events using normalized superposed epoch analysis

    NASA Astrophysics Data System (ADS)

    Katus, Roxanne M.; Liemohn, Michael W.; Gallagher, Dennis L.; Ridley, Aaron; Zou, Shasha

    2013-01-01

    Abstract<p label="1">The relative contribution of <span class="hlt">storm</span>-time ring current development by <span class="hlt">convection</span> driven by either potential or inductive electric fields has remained an unresolved question in geospace research. Studies have been published supporting each side of this debate, including views that ring current buildup is entirely one or the other. This study presents new insights into the relative roles of these <span class="hlt">storm</span> main phase processes. We perform a superposed epoch study of 97 intense (DstMin < -100 nT) and 91 moderate (-50 nT > DstMin > -100 nT) <span class="hlt">storms</span> using OMNI solar wind and ground-based data. Instead of using a single reference time for the superpositioning of the events, we choose four reference times and expand or contract each phase of every event to the average length of this phase, creating a normalized timeline for the superposed epoch analysis. Using the bootstrap method, we statistically demonstrate that timeline normalization results in better reproduction of average <span class="hlt">storm</span> dynamics than conventional methods. Examination of the Dst reveals an inflection point in the intense <span class="hlt">storm</span> group consistent with two-step main phase development, which is supported by results for the southward interplanetary magnetic field and various ground-based magnetic indices. This two-step main-phase process is not seen in the moderate <span class="hlt">storm</span> timeline and data sets. It is determined that the first step of Dst development is due to potential <span class="hlt">convective</span> drift, during which an initial ring current is formed. The negative feedback of this hot ion population begins to limit further ring current growth. The second step of the main phase, however, is found to be a more even mix of potential and inductive <span class="hlt">convection</span>. It is hypothesized that this is necessary to achieve intense <span class="hlt">storm</span> Dst levels because the substorm dipolarizations are effective at breaking through the negative feedback barrier of the existing inner magnetospheric hot ion pressure peak.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016MAP...128..303B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016MAP...128..303B"><span id="translatedtitle">Lightning characteristics of derecho producing mesoscale <span class="hlt">convective</span> systems</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bentley, Mace L.; Franks, John R.; Suranovic, Katelyn R.; Barbachem, Brent; Cannon, Declan; Cooper, Stonie R.</p> <p>2016-06-01</p> <p>Derechos, or widespread, <span class="hlt">convectively</span> induced wind <span class="hlt">storms</span>, are a common warm season phenomenon in the Central and Eastern United States. These damaging and severe weather events are known to sweep quickly across large spatial regions of more than 400 km and produce wind speeds exceeding 121 km h-1. Although extensive research concerning derechos and their parent mesoscale <span class="hlt">convective</span> systems already exists, there have been few investigations of the spatial and temporal distribution of associated cloud-to-ground lightning with these events. This study analyzes twenty warm season (May through August) derecho events between 2003 and 2013 in an effort to discern their lightning characteristics. Data used in the study included cloud-to-ground flash data derived from the National Lightning Detection Network, WSR-88D imagery from the University Corporation for Atmospheric Research, and damaging wind report data obtained from the <span class="hlt">Storm</span> Prediction Center. A spatial and temporal analysis was conducted by incorporating these data into a geographic information system to determine the distribution and lightning characteristics of the environments of derecho producing mesoscale <span class="hlt">convective</span> systems. Primary foci of this research include: (1) finding the approximate size of the lightning activity region for individual and combined event(s); (2) determining the intensity of each event by examining the density and polarity of lightning flashes; (3) locating areas of highest lightning flash density; and (4) to provide a lightning spatial analysis that outlines the temporal and spatial distribution of flash activity for particularly strong derecho producing thunderstorm episodes.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016SPIE.9876E..18P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016SPIE.9876E..18P"><span id="translatedtitle">Evaluation of a <span class="hlt">convective</span> downburst prediction application for India</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Pryor, Kenneth L.; Johny, C. J.; Prasad, V. S.</p> <p>2016-05-01</p> <p>During the month of June 2015, the South Asian (or Southwest) monsoon advanced steadily from the southern to the northwestern states of India. The progression of the monsoon had an apparent effect on the relative strength of <span class="hlt">convective</span> <span class="hlt">storm</span> downbursts that occurred during June and July 2015. A <span class="hlt">convective</span> downburst prediction algorithm, involving the Microburst Windspeed Potential Index (MWPI) and a satellite-derived three-band microburst risk product, and applied with meteorological geostationary satellite (KALPANA-1 VHRR and METEOSAT-7) and MODIS Aqua data, was evaluated and found to effectively indicate relative downburst intensity in both pre-monsoon and monsoon environments over various regions of India. The MWPI product, derived from T574L64 Global Forecast System (NGFS) model data, is being generated in real-time by National Center for Medium Range Weather Forecasting (NCMRWF), Ministry of Earth Sciences, India. The validation process entailed direct comparison of measured downburst-related wind gusts at airports and India Meteorological Department (IMD) observatories to adjacent MWPI values calculated from GFS and India NGFS model datasets. Favorable results include a statistically significant positive correlation between MWPI values and proximate measured downburst wind gusts with a confidence level near 100%. Case studies demonstrate the influence of the South Asian monsoon on <span class="hlt">convective</span> <span class="hlt">storm</span> environments and the response of the downburst prediction algorithm.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2014PhDT........64G&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2014PhDT........64G&link_type=ABSTRACT"><span id="translatedtitle">The relative influence of aerosols and the environment on organized tropical and midlatitude deep <span class="hlt">convection</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Grant, Leah Danielle</p> <p></p> <p>In this two-part study, the relative impacts of aerosols and the environment on organized deep <span class="hlt">convection</span>, including tropical sea-breeze <span class="hlt">convection</span> and midlatitude supercellular and multicellular deep <span class="hlt">convection</span>, are investigated within idealized cloud-resolving modeling simulations using the Regional Atmospheric Modeling System (RAMS). Part one explores aerosol-cloud-land surface interactions within tropical deep <span class="hlt">convection</span> organized along a sea breeze front. The idealized RAMS domain setup is representative of the coastal Cameroon rainforest in equatorial Africa. In order to assess the potential sensitivity of sea-breeze <span class="hlt">convection</span> to increasing anthropogenic activity and deforestation occurring in such regions, 27 total simulations are performed in which combinations of enhanced aerosol concentrations, reduced surface roughness length, and reduced soil moisture are included. Both enhanced aerosols and reduced soil moisture are found to individually reduce the precipitation due to reductions in downwelling shortwave radiation and surface latent heat fluxes, respectively, while perturbations to the roughness length do not have a large impact on the precipitation. The largest soil moisture perturbations dominate the precipitation changes due to reduced low-level moisture available to the <span class="hlt">convection</span>, but if the soil moisture perturbation is moderate, synergistic interactions between soil moisture and aerosols enhance the sea breeze precipitation. This is found to result from evening <span class="hlt">convection</span> that forms ahead of the sea breeze only when both effects are present. Interactions between the resulting gust fronts and the sea breeze front locally enhance convergence and therefore the rainfall. Part two of this study investigates the relative roles of midlevel dryness and aerosols on supercellular and multicellular <span class="hlt">convective</span> morphology. A common <span class="hlt">storm</span>-splitting situation is simulated wherein the right-moving <span class="hlt">storm</span> becomes a dominant supercell and the left-moving <span class="hlt">storm</span></p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016cosp...41E1871S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016cosp...41E1871S"><span id="translatedtitle">First results on climatological response of Indian low latitude ionosphere to geomagnetic <span class="hlt">storms</span> during solar cycle 23 and 24</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Suresh, Sunanda; Dashora, Nirvikar</p> <p>2016-07-01</p> <p>For the first time, a climatological response of low latitude ionosphere to geomagnetic <span class="hlt">storms</span> is presented using long term global ionospheric maps (GIM) data from June 1998 to June 2015 covering two solar cycles 23 and 24. The results are not only the first from Indian region but also the first around the globe to bring latitudinal character of daytime ionospheric <span class="hlt">storms</span> with use of newly defined criteria. The results are presented for daytime forenoon and afternoon sectors under minor, moderate and major ionospheric <span class="hlt">storm</span> categories based on minimum Dst index criterion. For the first time the effectiveness of <span class="hlt">storms</span> is identified using monthly standard deviation as an indicator of the day-to-day variability in equatorial and low latitude ionosphere. Thus results on climatology are definitive and form a data base that would be comparable to statistical results from any other longitude and time. Seasonal statistics for total <span class="hlt">storms</span>, effective positive and negative <span class="hlt">storms</span>, and amplitude of mean seasonal perturbation in total electron content are obtained. Total and effective <span class="hlt">storms</span> are found to be higher in solar cycle 23 than in 24 and only couple of effective <span class="hlt">storms</span> occurred during low solar activity 2007-2009 that also in minor category. Afternoon sector is found to be favourable for occurrence of maximum number of effective positive <span class="hlt">storms</span>. A latitudinal preference is found for a given <span class="hlt">storm</span> to be effective in either time sectors. Equinoctial asymmetry in ionospheric response both in terms of occurrence and perturbation amplitude is found. September equinoxes are found to bear maximum total, effective positive and negative <span class="hlt">storms</span>. Winters are found more prone to negative <span class="hlt">storms</span> whereas <span class="hlt">summers</span> have recorded minimum number of either of <span class="hlt">storms</span> and minimum perturbation amplitudes.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009pcms.confE.183C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009pcms.confE.183C"><span id="translatedtitle">New opportunities for the study of Mediterranean <span class="hlt">storms</span>: the unique capabilities of the Global Hawk aircraft</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Cairo, F.; Curry, R. E.; Carli, B.</p> <p>2009-09-01</p> <p> particular emphasis on Saharan Air Layer (SAL) events. The frequent occurrence of such events, influencing the development of heavy precipitation systems in the region, as they do for hurricane genesis in the Atlantic west of Africa, promts the study of their impact on microphysical processes during precipitation formation; on lower and upper atmosphere destabilization stemming respectively from the production of a deep mixed layer of near zero potential vorticity and from the associated capping warm layer; and on their radiative impact leading to an enhanced heating of the lower troposphere due to solar radiation absorption by the Saharan dust itself. A different area of investigation would be the study of origin and fate of strong mesoscale disturbances originating in the area during the end of <span class="hlt">Summer</span> and Fall period. In fact, while most Mediterranean <span class="hlt">storms</span> have classic baroclinic origins, there are intense mesoscale <span class="hlt">convective</span> <span class="hlt">storms</span> which form and evolve into warm core structures deriving their energy directly from the warm sea surface in a fashion similar to tropical cyclones, e.g. hurricanes and typhoons. This type of tropical-like <span class="hlt">storms</span> have been named Medicanes: understanding their origin and development is of utmost importance in view of their potential changing response in relationship to expected climate changes since it has been speculated that these Mediterranean <span class="hlt">storms</span> would become more frequent and more vigorous in the near future due to the Mediterranean sea-surface temperature increase that is (probably) already occurring because of global warming. Remote sensing instrumentation (radars, microwave radiometers, lidars) is a primary tool to address this issue from a high-flying platform, to improve the understanding of the thermodynamics, dynamics, and microphysics of clouds, by measuring the evolution of their 3-dimensional thermodynamical, dynamical, and microphysical structures and the 3-dimensional structure and evolution of the aerosol content. The long</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1983ihaa.conf..187P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1983ihaa.conf..187P"><span id="translatedtitle">Le couplage pulsation-<span class="hlt">convection</span>.</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Poyet, J.-P.</p> <p></p> <p>Contents: Quelques problèmes Boussinesq bien definis. Les théories de couplage pulsation radiale-<span class="hlt">convection</span>. Quelques pas dans le domaine du couplage des pulsations non radiales avec la <span class="hlt">convection</span>. Conclusion.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011AtmRe.100..334G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011AtmRe.100..334G"><span id="translatedtitle">Tornadoes and severe <span class="hlt">storms</span> in Spain</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gayà, Miquel</p> <p>2011-06-01</p> <p>A climatology of tornadoes, waterspouts, and straight winds linked to <span class="hlt">convection</span> in Spain is presented. The database is divided into three periods according to the main source of information. The three distributions of severe weather are very sensitive to the sources of information, much more than to a possible change in climate. The early period, up to 1825, comprises cases that contain the real facts together with spurious inputs such as religion, myths, beliefs, etc, mixed in an unknown proportion. The period between 1826 and 1975, and the most recent one, up to 2009, enable us to observe geographical and temporal variations as a function of societal changes. The analysis of temporal and geographical distributions allows us to frame the risk in the face of severe <span class="hlt">storms</span>, and the changes in their perception and management that have come about over time. Although the most recent tornadoes have been weak or strong, the Cádiz tornado of 1671 demonstrates that an extremely rare and violent event can occur in Spain. The large number of victims claimed by this tornado makes it one of the most important in the world.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li class="active"><span>19</span></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_19 --> <div id="page_20" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li class="active"><span>20</span></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="381"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/6730037','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/6730037"><span id="translatedtitle">Natural <span class="hlt">convection</span> in porous media</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Prasad, V.; Hussain, N.A.</p> <p>1986-01-01</p> <p>This book presents the papers given at a conference on free <span class="hlt">convection</span> in porous materials. Topics considered at the conference included heat transfer, nonlinear temperature profiles and magnetic fields, boundary conditions, concentrated heat sources in stratified porous media, free <span class="hlt">convective</span> flow in a cavity, heat flux, laminar mixed <span class="hlt">convection</span> flow, and the onset of <span class="hlt">convection</span> in a porous medium with internal heat generation and downward flow.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFM.A22A..02R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFM.A22A..02R"><span id="translatedtitle">Chaotic <span class="hlt">Convection</span> in CAM</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Randall, D. A.; Branson, M.; Dutta, R.; Jones, T.</p> <p>2015-12-01</p> <p>It has been suggested that stochastic fluctuations of <span class="hlt">convective</span> activity can lead to systematic changes in large-scale weather and climate. We present results of recent ensemble-prediction experiments with the super-parameterized version of CAM that provide a new way to explore such effects, without the need for adhoc assumptions about the nature of the stochastic effects.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19840026019','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19840026019"><span id="translatedtitle">A kinetic energy study of the meso beta-scale <span class="hlt">storm</span> environment during AVE-SESAME 5 (20-21 May 1979)</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Printy, M. F.; Fuelberg, H. E.</p> <p>1984-01-01</p> <p>Kinetic energy of the near <span class="hlt">storm</span> environment was analyzed by meso beta scale data. It was found that horizontal winds in the 400 to 150 mb layer strengthen rapidly north of the developing <span class="hlt">convection</span>. Peak values then decrease such that the maximum disappears 6 h later. Southeast of the <span class="hlt">storms</span>, wind speeds above 300 mb decrease nearly 50% during the 3 h period of most intense thunderstorm activity. When the <span class="hlt">convection</span> dissipates, wind patterns return to prestorm conditions. The mesoscale <span class="hlt">storm</span> environment of AVE-SESAME 5 is characterized by large values of cross contour generation of kinetic energy, transfers of energy to nonresolvable scales of motion, and horizontal flux divergence. These processes are maximized within the upper troposphere and are greatest during times of strongest <span class="hlt">convection</span>. It is shown that patterns agree with observed weather features. The southeast area of the network is examined to determine causes for vertical wind variations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2002QJRMS.128..893F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2002QJRMS.128..893F"><span id="translatedtitle">Upstream influence of numerically simulated squall-line <span class="hlt">storms</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Fovell, Robert G.</p> <p>2002-04-01</p> <p>The squall line's impact on its upstream environment is examined using traditional cloud and simplified (parametrized moisture) models. The study was motivated by the need to explain significant differences between the two dynamical frameworks. In both, the first environmental response to the <span class="hlt">convection</span> consists of a rapidly propagating gravity wave characterized by deep tropospheric subsidence. This gravity wave accelerates the lowlevel <span class="hlt">storm</span> inflow in its wake, with the largest effect seen near the surface. In the more sophisticated model, however, this wave is eventually followed by a shorter vertical wavelength feature, one possessing lower-tropospheric ascent. This second gravity wave, absent from the simplified model runs, substantially alters the upstream environment yet again. The gentle low-level uplift establishes the 'cool/moist tongue' ofairthat has been found to stretch well ahead of the <span class="hlt">storm</span> in simulations. Between the second wave and the main <span class="hlt">storm</span> updraught, the accelerated inflow is shifted from the ground to the middle troposphere where it helps to push dry air into the <span class="hlt">convecting</span> region. This subsequent environmental adjustment responds to the establishment of a small yet persistent area of weak cooling during the early mature phase. Located in the middle troposphere at the upstream edge of the main cloud mass, this cooling is the combined effect of cloud-water evaporation and the ascent of subsaturated air. Though the cooling that excites it is of relatively small magnitude (<2 K), this wave's effect is dramatic and significant. A crude fix to the moisture parametrization served to establish a qualitatively similar tongue-like feature in the simplified model simulations, bringing the results from the two dynamical frameworks more into line.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19930039186&hterms=oxygen+transport&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Doxygen%2Btransport','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19930039186&hterms=oxygen+transport&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Doxygen%2Btransport"><span id="translatedtitle">Radial transport of <span class="hlt">storm</span> time ring current ions</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Lui, A. T. Y.</p> <p>1993-01-01</p> <p>Radial transport of energetic ions for the development of the main phase of geomagnetic <span class="hlt">storms</span> is investigated with data from the medium energy particle analyzer (MEPA) on the Charge Composition Explorer spacecraft, which monitored protons, helium ions, and the carbon-nitrogen-oxygen group, which is mostly dominated by oxygen ions. From a study of four geomagnetic <span class="hlt">storms</span>, we show that the flux increase of these ions in the inner ring current region can be accounted for by an inward displacement of the ring current population by 0.5 to 3.5 R(E). There is a general trend that a larger inward displacement occurs at higher L shells than at lower ones. These results are in agreement with previous findings. The radially injected population consists of the prestorm population modified by substorm injections which occur on a much shorter time scale than that for a <span class="hlt">storm</span> main phase. It is also found that the inward displacement is relatively independent of ion mass and energy, suggesting that the radial transport of these energetic ions is effected primarily by <span class="hlt">convective</span> motion from a large electric field or by diffusion resulting from magnetic field fluctuations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://eric.ed.gov/?q=time+AND+travel&pg=4&id=EJ996841','ERIC'); return false;" href="http://eric.ed.gov/?q=time+AND+travel&pg=4&id=EJ996841"><span id="translatedtitle">Book Your <span class="hlt">Summer</span> Vacation</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Texley, Juliana</p> <p>2012-01-01</p> <p><span class="hlt">Summer</span>'s the time for teachers to travel, not only physically from the confines of the classroom to exotic places, but vicariously, through the magic of books. <span class="hlt">Summer</span> adventures help teachers expand their experience and enrich their store of context so that they can offer their students more when school resumes in the fall. That's why each year…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://eric.ed.gov/?q=Fireworks&id=EJ769694','ERIC'); return false;" href="http://eric.ed.gov/?q=Fireworks&id=EJ769694"><span id="translatedtitle">Celebrate <span class="hlt">Summer</span> with Reading</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Texley, Juliana</p> <p>2007-01-01</p> <p>School is out and the <span class="hlt">summer</span> is full of both official and unofficial holidays that prompt us to enjoy science and the profession of sharing it. As in past years, the reviewers and editors of "NSTA Recommends"--ready and willing to share their enthusiasm for reading with you--have been gathering suggestions for the <span class="hlt">summer</span>. So along with your beach…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://eric.ed.gov/?q=sky&id=EJ850041','ERIC'); return false;" href="http://eric.ed.gov/?q=sky&id=EJ850041"><span id="translatedtitle">Under <span class="hlt">Summer</span> Skies</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Texley, Juliana</p> <p>2009-01-01</p> <p>There's no better way to celebrate 2009, the International Year of Astronomy, than by curling up with a good book under <span class="hlt">summer</span> skies. To every civilization, in every age, the skies inspired imagination and scientific inquiry. There's no better place to start your <span class="hlt">summer</span> reading than under their influence. Here are a few selections identified by…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://eric.ed.gov/?q=slam&id=EJ977212','ERIC'); return false;" href="http://eric.ed.gov/?q=slam&id=EJ977212"><span id="translatedtitle">School Construction <span class="hlt">Summer</span> Slam</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Jensen, Richard F.</p> <p>2012-01-01</p> <p>Every school has a list of renovations, upgrades and repairs that need attention, but many are too distracting and disruptive to carry out during the school year. Often, the best time to address these nagging construction projects is during the <span class="hlt">summer</span> when students are on break and the campus is quieter. Although these "<span class="hlt">summer</span> slammers" often are…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://files.eric.ed.gov/fulltext/EJ993187.pdf','ERIC'); return false;" href="http://files.eric.ed.gov/fulltext/EJ993187.pdf"><span id="translatedtitle">Your Best <span class="hlt">Summer</span> Ever</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Cleaver, Samantha</p> <p>2012-01-01</p> <p>"It must be nice to have <span class="hlt">summers</span> off." Only other teachers know just how short <span class="hlt">summer</span> is, with much of August devoted to planning for the new school year. This article offers 17 fresh ideas for exploring, making money, and preparing for next year. Plus, a reading list that hits all the marks!</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EGUGA..18.3054F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EGUGA..18.3054F"><span id="translatedtitle">Impact of different <span class="hlt">convection</span> permitting resolutions on the representation of heavy rainfall over the UK</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Fosser, Giorgia; Kendon, Elizabeth; Chan, Steven</p> <p>2016-04-01</p> <p>The <span class="hlt">convection</span> parameterisation schemes used global and regional climate models (with grid spacings of order 10-100 km) are a known source of model deficiencies, leading to errors in the diurnal cycle of <span class="hlt">summer</span> precipitation and an underestimation of hourly precipitation extremes. As grid spacings approach the km-scale, the so-called "<span class="hlt">convection</span> permitting" scale, it is possible to represent deep <span class="hlt">convection</span> explicitly. Previous studies (e.g. Ban et al, 2015; Fosser et al, 2015; Kendon et al, 2015) have show that these <span class="hlt">convection</span> permitting models are able to give a much more realistic representation of <span class="hlt">convection</span>, and are needed to provide reliable projections of future changes in hourly precipitation extremes. In this context, the UKCP18 project aims to provide policy makers with new UK climate change projections at hourly and local scales, thanks to the first ensemble of runs at <span class="hlt">convection</span> permitting resolution. This study outlines the benefits of <span class="hlt">convection</span>-permitting resolution in terms of the representation of heavy rainfall, and investigates the impacts of different <span class="hlt">convection</span> permitting resolutions as well as the domain size. Bibliography Ban N, Schmidli J, Schär C (2015) Heavy precipitation in a changing climate: Does short-term <span class="hlt">summer</span> precipitation increase faster? Geophys Res Lett 42:1165-1172. doi: 10.1002/2014GL062588 Fosser G, Khodayar S, Berg P (2015) Benefit of <span class="hlt">convection</span> permitting climate model simulations in the representation of <span class="hlt">convective</span> precipitation. Clim Dyn. doi: 10.1007/s00382-014-2242-1 Kendon EJ, Roberts NM, Fowler HJ, et al (2014) Heavier <span class="hlt">summer</span> downpours with climate change revealed by weather forecast resolution model. Nat Clim Chang 4:570-576. doi: 10.1038/nclimate2258</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19910031493&hterms=study+composite&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3Dstudy%2Bcomposite','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19910031493&hterms=study+composite&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3Dstudy%2Bcomposite"><span id="translatedtitle">A composite study of onset of the Australian <span class="hlt">summer</span> monsoon</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Hendon, Harry H.; Liebmann, Brant</p> <p>1990-01-01</p> <p>The circulation changes that accompany an onset (defined as the first occurrence of wet 850-mb westerly winds at Darwin, Australia) of the Australian <span class="hlt">summer</span> monsoon are documented by a composite study for the years 1957-1987. Composites of atmospheric fields at stations in and about the Australian tropics are constructed relative to the onset data at Darwin. It is shown that the composite onset is dominated by a slow eastward migration of a deep-baroclinic <span class="hlt">convective</span> circulation displaced south of the equator. This propagating anomaly exhibited many features of the so-called 40-50 day oscillation, including an upper level anticyclone that accompanies the <span class="hlt">convective</span> anomaly.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19910028057&hterms=plane+wave+spectrum&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dplane%2Bwave%2Bspectrum','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19910028057&hterms=plane+wave+spectrum&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dplane%2Bwave%2Bspectrum"><span id="translatedtitle">Wave generation by turbulent <span class="hlt">convection</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Goldreich, Peter; Kumar, Pawan</p> <p>1990-01-01</p> <p>Wave generation by turbulent <span class="hlt">convection</span> in a plane parallel, stratified atmosphere lying in a gravitational field is studied. The turbulent spectrum is related to the <span class="hlt">convective</span> energy flux via the Kolmogorov scaling and the mixing length hypothesis. Efficiencies for the conversion of the <span class="hlt">convective</span> energy flux into both trapped and propagating waves are estimated.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19850044001&hterms=Kinetic+energy&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3DKinetic%2Benergy','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19850044001&hterms=Kinetic+energy&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3DKinetic%2Benergy"><span id="translatedtitle">A kinetic energy analysis of the meso beta-scale severe <span class="hlt">storm</span> environment</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Fuelberg, H. E.; Printy, M. F.</p> <p>1984-01-01</p> <p>Analyses are performed of the meso beta-scale (20-200 km wavelengths and several hours to one-day periods) severe <span class="hlt">storm</span> kinetic energy balance on the fifth day of the AVE SESAME campaign of May 1979. A 24-hr interval covering the antecedent, active and post-<span class="hlt">convective</span> outbreak activity over Oklahoma are considered. Use is made of the kinetic energy budget equation (KEBE) for a finite volume in an isobaric coordinate system. Rawindsonde data with 75 km resolution were treated. The KEBE model covered changes in kinetic energy due to the cross contour flows, horizontal and vertical components of flux divergence, and volumic mass changes on synoptic and subsynoptic scales. The greatest variability was concentrated above 400 mb height and over the most intense <span class="hlt">storm</span> activity. Energy was generated at the highest rates in divergence and decreased the most in <span class="hlt">convection</span>. The meso beta-scale lacked sufficient resolution for analyzing mesoscale activity.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20020083157&hterms=Pu&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3DPu','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20020083157&hterms=Pu&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3DPu"><span id="translatedtitle">High-Resolution Simulation of Hurricane Bonnie (1998): <span class="hlt">Storm</span> Structure and Evolution</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Braun, Scott A.; Pu, Zhaoxia; Starr, David OC. (Technical Monitor)</p> <p>2002-01-01</p> <p>A simulation of Hurricane Bonnie (1998) has been performed using multiple grid nesting to 2 km grid spacing. The simulation is initialized with large-scale analysis fields from the European Center for Medium Range Forecasts and with a bogus vortex inserted via four-dimensional variational data assimilation. The simulation, verified against radar observations from TRMM and aircraft observations from the NASA CAMEX-3 field experiment, reproduces well the <span class="hlt">storm</span> intensity, the wavenumber 1 asymmetry of the precipitation field, the occurrence of deep <span class="hlt">convective</span> towers within the eyewall, and the presence of broad stratiform precipitation regions. This study will explore the evolution of air parcels in these <span class="hlt">convective</span> towers, from their beginnings in the boundary layer to their movement in upper level outflow. The role of these towers in <span class="hlt">storm</span> intensification may also be examined.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3409726','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3409726"><span id="translatedtitle">Anomalously weak solar <span class="hlt">convection</span></span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Hanasoge, Shravan M.; Duvall, Thomas L.</p> <p>2012-01-01</p> <p><span class="hlt">Convection</span> in the solar interior is thought to comprise structures on a spectrum of scales. This conclusion emerges from phenomenological studies and numerical simulations, though neither covers the proper range of dynamical parameters of solar <span class="hlt">convection</span>. Here, we analyze observations of the wavefield in the solar photosphere using techniques of time-distance helioseismology to image flows in the solar interior. We downsample and synthesize 900 billion wavefield observations to produce 3 billion cross-correlations, which we average and fit, measuring 5 million wave travel times. Using these travel times, we deduce the underlying flow systems and study their statistics to bound <span class="hlt">convective</span> velocity magnitudes in the solar interior, as a function of depth and spherical-harmonic degree ℓ. Within the wavenumber band ℓ < 60, <span class="hlt">convective</span> velocities are 20–100 times weaker than current theoretical estimates. This constraint suggests the prevalence of a different paradigm of turbulence from that predicted by existing models, prompting the question: what mechanism transports the heat flux of a solar luminosity outwards? Advection is dominated by Coriolis forces for wavenumbers ℓ < 60, with Rossby numbers smaller than approximately 10-2 at r/R⊙ = 0.96, suggesting that the Sun may be a much faster rotator than previously thought, and that large-scale <span class="hlt">convection</span> may be quasi-geostrophic. The fact that isorotation contours in the Sun are not coaligned with the axis of rotation suggests the presence of a latitudinal entropy gradient. PMID:22665774</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016RaSc...51..524B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016RaSc...51..524B"><span id="translatedtitle">High-latitude topside ionospheric vertical electron density profile changes in response to large magnetic <span class="hlt">storms</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Benson, Robert F.; Fainberg, Joseph; Osherovich, Vladimir A.; Truhlik, Vladimir; Wang, Yongli; Bilitza, Dieter; Fung, Shing F.</p> <p>2016-05-01</p> <p>Large magnetic-<span class="hlt">storm</span>-induced changes were detected in high-latitude topside vertical electron density profiles Ne(h) in a database of profiles and digital topside ionograms, from the International Satellites for Ionospheric Studies (ISIS) program, that enabled Ne(h) profiles to be obtained in nearly the same region of space before, during, and after a major magnetic <span class="hlt">storm</span> (Dst < -100 nT). <span class="hlt">Storms</span> where Ne(h) profiles were available in the high-latitude Northern Hemisphere had better coverage of solar wind parameters than <span class="hlt">storms</span> with available Ne(h) profiles in the high-latitude Southern Hemisphere. Large Ne(h) changes were observed during all <span class="hlt">storms</span>, with enhancements and depletions sometimes near a factor of 10 and 0.1, respectively, but with substantial differences in the responses in the two hemispheres. Large spatial and/or temporal Ne(h) changes were often observed during Dst minimum and during the <span class="hlt">storm</span> recovery phase. The <span class="hlt">storm</span>-induced Ne(h) changes were the most pronounced and consistent in the Northern Hemisphere in that large enhancements were observed during winter nighttime and large depletions during winter and spring daytime. The limited available cases suggested that these Northern Hemisphere enhancements increased with increases of the time-shifted solar wind velocity v, magnetic field B, and with more negative values of the B components except for the highest common altitude (1100 km) of the profiles. There was also some evidence suggesting that the Northern Hemisphere depletions were related to changes in the solar wind parameters. Southern Hemisphere <span class="hlt">storm</span>-induced enhancements and depletions were typically considerably less with depletions observed during <span class="hlt">summer</span> nighttime conditions and enhancements during <span class="hlt">summer</span> daytime and fall nighttime conditions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2006AtmRe..82..350S&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2006AtmRe..82..350S&link_type=ABSTRACT"><span id="translatedtitle">A comparison of the microphysical and kinematic characteristics of mid-latitude and tropical <span class="hlt">convective</span> updrafts and downdrafts</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Stith, J. L.; Haggerty, J.; Grainger, C.; Detwiler, A.</p> <p>2006-11-01</p> <p>Airborne measurements of updraft speeds, liquid water content and other microphysical parameters were measured in <span class="hlt">convective</span> <span class="hlt">storms</span> during two mid-latitude <span class="hlt">summers</span> in North Dakota, USA, and in two tropical locations (the continental Amazon region in tropical South America and Kwajalein in the tropical central Pacific Ocean). Data representing 0.5 km averages of data collected from a large number of clouds sampled during the field seasons are examined. In the North Dakota clouds, updraft values of a given magnitude were found about as often as downdrafts of similar magnitude in midlevels of the clouds, while lower levels favored downdrafts and upper levels favored updrafts. Drafts in tropical clouds were much weaker and favored updrafts in mid to upper regions of the clouds (the lower levels were not sampled). In two temperature regions (- 5 to - 12 °C and - 12 to - 20 °C), there was little difference in the frequency of occurrence of liquid water content values in the North Dakota clouds, while in the tropical clouds, higher liquid water contents were less likely to be found in the colder temperature intervals. The particle concentrations measured by FSSP instruments were similar in lower and midlevels of the North Dakota clouds, and decreased in upper levels. In the tropical clouds, the concentrations were similar in the mid and upper regions of the clouds. These results are discussed in terms of previous measurements of midlatitude and tropical clouds.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20090001834&hterms=Face+model&qs=N%3D0%26Ntk%3DTitle%26Ntx%3Dmode%2Bmatchall%26Ntt%3DFace%2Bmodel','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20090001834&hterms=Face+model&qs=N%3D0%26Ntk%3DTitle%26Ntx%3Dmode%2Bmatchall%26Ntt%3DFace%2Bmodel"><span id="translatedtitle">CO Signatures in Subtropical <span class="hlt">Convective</span> Clouds and Anvils During CRYSTAL-FACE: An Analysis of <span class="hlt">Convective</span> Transport and Entertainment Using Observations and a Cloud-Resolving Model</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Lopez, Jimena P.; Fridlind, Ann M.; Jost, Hans-Jurg; Loewenstein, Max; Ackerman, Andrew S.; Campos, Teresa L.; Weinstock, Elliot M.; Sayres, David S.; Smith, Jessica B.; Pittman, Jasna V.; Hallar, A. Gannet; Avallone, Linnea M.; Davis, Sean M.; Herman, Robert L.</p> <p>2006-01-01</p> <p><span class="hlt">Convective</span> systems are an important mechanism in the transport of boundary layer air into the upper troposphere. The Cirrus Regional Study of Tropical Anvils and Cirrus Layers-Florida Area Cirrus Experiment (CRYSTAL-FACE) campaign, in July 2002, was developed as a comprehensive atmospheric mission to improve knowledge of subtropical cirrus systems and their roles in regional and global climate. In situ measurements of carbon monoxide (CO), water vapor (H20v), and total water (H20t) aboard NASA's . WB-57F aircraft and CO aboard the U.S. Navy's Twin Otter aircraft were obtained to study the role of <span class="hlt">convective</span> transport. Three flights sampled <span class="hlt">convective</span> outflow on 11, 16 and 29 July found varying degrees of CO enhancement relative to the fiee troposphere. A cloud-resolving model used the in situ observations and meteorological fields to study these three systems. Several methods of filtering the observations were devised here using ice water content, relative humidity with respect to ice, and particle number concentration as a means to statistically sample the model results to represent the flight tracks. A weighted histogram based on ice water content observations was then used to sample the simulations for the three flights. In addition, because the observations occurred in the <span class="hlt">convective</span> outflow cirrus and not in the <span class="hlt">storm</span> cores, the model was used to estimate the maximum CO within the <span class="hlt">convective</span> systems. In general, anvil-level air parcels contained an estimated 20-40% boundary layer air in the analyzed <span class="hlt">storms</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20060050040&hterms=Face+model&qs=N%3D0%26Ntk%3DTitle%26Ntx%3Dmode%2Bmatchall%26Ntt%3DFace%2Bmodel','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20060050040&hterms=Face+model&qs=N%3D0%26Ntk%3DTitle%26Ntx%3Dmode%2Bmatchall%26Ntt%3DFace%2Bmodel"><span id="translatedtitle">CO Signatures in Subtropical <span class="hlt">Convective</span> Clouds and Anvils during CRYSTAL-FACE: An Analysis of <span class="hlt">Convective</span> Transport and Entrainment using Observations and a Cloud-Resolving Model</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Lopez, Jimena P.; Fridlind, Ann M.; Jost, Hans-Juerg; Loewenstein, Max; Ackerman, Andrew S.; Campos, Teresa L.; Weinstock, Elliot M.; Sayres, David S.; Smith, Jessica B.; Pittman, Jasna V.</p> <p>2006-01-01</p> <p><span class="hlt">Convective</span> systems are an important mechanism in the transport of boundary layer air into the upper troposphere. The Cirrus Regional Study of Tropical Anvils and Cirrus Layers-Florida Area Cirrus Experiment (CRYSTAL-FACE) campaign, in July 2002, was developed as a comprehensive atmospheric mission to improve knowledge of subtropical cirrus systems and their roles in regional and global climate. In situ measurements of carbon monoxide (CO), water vapor (H2Ov), and total water (H2Ot) aboard NASA's WB-57F aircraft and CO aboard the U.S. Navy's Twin Otter aircraft were obtained to study the role of <span class="hlt">convective</span> transport. Three flights sampled <span class="hlt">convective</span> outflow on 11, 16 and 29 July found varying degrees of CO enhancement relative to the free troposphere. A cloud-resolving model used the in situ observations and meteorological fields to study these three systems. Several methods of filtering the observations were devised here using ice water content, relative humidity with respect to ice, and particle number concentration as a means to statistically sample the model results to represent the flight tracks. A weighted histogram based on ice water content observations was then used to sample the simulations for the three flights. In addition, because the observations occurred in the <span class="hlt">convective</span> outflow cirrus and not in the <span class="hlt">storm</span> cores, the model was used to estimate the maximum CO within the <span class="hlt">convective</span> systems. In general, anvil-level air parcels contained an estimated 20-40% boundary layer air in the analyzed <span class="hlt">storms</span>.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li class="active"><span>20</span></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_20 --> <div id="page_21" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li class="active"><span>21</span></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="401"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AtmRe.156...91D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AtmRe.156...91D"><span id="translatedtitle">The influence of topography on vertical velocity of air in relation to severe <span class="hlt">storms</span> near the Southern Andes Mountains</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>de la Torre, A.; Pessano, H.; Hierro, R.; Santos, J. R.; Llamedo, P.; Alexander, P.</p> <p>2015-04-01</p> <p>On the basis of 180 <span class="hlt">storms</span> which took place between 2004 and 2011 over the province of Mendoza (Argentina) near to the Andes Range at southern mid-latitudes, we consider those registered in the northern and central crop areas (oases). The regions affected by these <span class="hlt">storms</span> are currently protected by an operational hail mitigation project. Differences with previously reported <span class="hlt">storms</span> detected in the southern oasis are highlighted. Mendoza is a semiarid region situated roughly between 32S and 37S at the east of the highest Andes top. It forms a natural laboratory where different sources of gravity waves, mainly mountain waves, occur. In this work, we analyze the effects of flow over topography generating mountain waves and favoring deep <span class="hlt">convection</span>. The joint occurrence of <span class="hlt">storms</span> with hail production and mountain waves is determined from mesoscale numerical simulations, radar and radiosounding data. In particular, two case studies that properly represent diverse structures observed in the region are considered in detail. A continuous wavelet transform is applied to each variable and profile to detect the main oscillation modes present. Simulated temperature profiles are validated and compared with radiosounding data. Each first radar echo, time and location are determined. The necessary energy to lift a parcel to its level of free <span class="hlt">convection</span> is tested from the <span class="hlt">Convective</span> Available Potential Energy and <span class="hlt">Convection</span> Inhibition. This last parameter is compared against the mountain waves' vertical kinetic energy. The time evolution and vertical structure of vertical velocity and equivalent potential temperature suggest in both cases that the detected mountain wave amplitudes are able to provide the necessary energy to lift the air parcel and trigger <span class="hlt">convection</span>. A simple conceptual scheme linking the dynamical factors taking place before and during <span class="hlt">storm</span> development is proposed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015EGUGA..17.5383A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015EGUGA..17.5383A"><span id="translatedtitle"><span class="hlt">Storm</span> tracks near marginal stability</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ambaum, Maarten; Novak, Lenka</p> <p>2015-04-01</p> <p>The variance of atmospheric <span class="hlt">storm</span> tracks is characterised by intermittent bursts of activity interspersed with relatively quiescent periods. Most of the poleward heat transport by <span class="hlt">storm</span> tracks is due to a limited number of strong heat flux events, which occur in a quasi-periodic fashion. This behaviour is in contradiction with the usual conceptual model of the <span class="hlt">storm</span> tracks, which relies on high growth rate background flows which then spawn weather systems that grow in an exponential or non-normal fashion. Here we present a different conceptual model of the atmospheric <span class="hlt">storm</span> tracks which is built on the observation that, when including diabatic and other dissipative effects, the <span class="hlt">storm</span> track region is in fact most of the time marginally stable. The ensuing model is a nonlinear oscillator, very similar to Volterra-Lotka predator-prey models. We demonstrate the extensions of this model to a stochastically driven nonlinear oscillator. The model produces quasi-periodic behaviour dominated by intermittent heat flux events. Perhaps most surprisingly, we will show strong evidence from re-analysis data for our conceptual model: the re-analysis data produces a phase-space plot that is very similar indeed to the phase-space plot for our nonlinear oscillator model.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=GL-2002-002530&hterms=consequences+tropical+storms&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dconsequences%2Btropical%2Bstorms','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=GL-2002-002530&hterms=consequences+tropical+storms&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dconsequences%2Btropical%2Bstorms"><span id="translatedtitle">Tropical <span class="hlt">Storms</span> Bud and Dera</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p></p> <p>2002-01-01</p> <p>Like dancers pirouetting in opposite directions, the rotational patterns of two different tropical <span class="hlt">storms</span> are contrasted in this pair of Multi-angle Imaging Spectroradiometer (MISR) nadir-camera images. The left-hand image is of Tropical <span class="hlt">Storm</span> Bud, acquired on June 17, 2000 (Terra orbit 2656) as the <span class="hlt">storm</span> was dissipating. Bud was situated in the eastern Pacific Ocean between Socorro Island and the southern tip of Baja California. South of the <span class="hlt">storm</span>'s center is a vortex pattern caused by obstruction of the prevailing flow by tiny Socorro Island. Sonora, Mexico and Baja California are visible at the top of the image. The right-hand image is of Tropical Cyclone Dera, acquired on March 12, 2001. Dera was located in the Indian Ocean, south of Madagascar. The southern end of this large island is visible in the top portion of this image. Northern hemisphere tropical <span class="hlt">storms</span>, like Bud, rotate in a counterclockwise direction, whereas those in the southern hemisphere, such as Dera, rotate clockwise. The opposite spins are a consequence of Earth's rotation. Each image covers a swath approximately 380 kilometers wide. Image courtesy NASA/JPL/GSFC/LaRC, MISR Team</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=PIA03400&hterms=consequences+tropical+storms&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dconsequences%2Btropical%2Bstorms','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=PIA03400&hterms=consequences+tropical+storms&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dconsequences%2Btropical%2Bstorms"><span id="translatedtitle">Tropical <span class="hlt">Storms</span> Bud and Dera</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p></p> <p>2001-01-01</p> <p><p/>Like dancers pirouetting in opposite directions, the rotational patterns of two different tropical <span class="hlt">storms</span> are contrasted in this pair of MISR nadir-camera images.<p/>The left-hand image is of Tropical <span class="hlt">Storm</span> Bud, acquired on June 17, 2000 (Terra orbit 2656) as the <span class="hlt">storm</span> was dissipating. Bud was situated in the eastern Pacific Ocean between Socorro Island and the southern tip of Baja California. South of the <span class="hlt">storm</span>'s center is a vortex pattern caused by obstruction of the prevailing flow by tiny Socorro Island. Sonora, Mexico and Baja California are visible at the top of the image.<p/>The right-hand image is of Tropical Cyclone Dera, acquired on March 12, 2001 (Terra orbit 6552). Dera was located in the Indian Ocean, south of Madagascar. The southern end of this large island is visible in the top portion of this image.<p/>Northern hemisphere tropical <span class="hlt">storms</span>, like Bud, rotate in a counterclockwise direction, whereas those in the southern hemisphere, such as Dera, rotate clockwise. The opposite spins are a consequence of Earth's rotation.<p/>Each image covers a swath approximately 380 kilometers wide.<p/>MISR was built and is managed by NASA's Jet Propulsion Laboratory, Pasadena, CA, for NASA's Office of Earth Science, Washington, DC. The Terra satellite is managed by NASA's Goddard Space Flight Center, Greenbelt, MD. JPL is a division of the California Institute of Technology.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/24960018','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24960018"><span id="translatedtitle">Contrasting patterns of nutrient dynamics during different <span class="hlt">storm</span> events in a semi-arid catchment of northern China.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Du, Xinzhong; Li, Xuyong; Hao, Shaonan; Wang, Huiliang; Shen, Xiao</p> <p>2014-01-01</p> <p>Nutrient discharge during <span class="hlt">storm</span> events is a critical pathway for nutrient export in semi-arid catchments. We investigated nutrient dynamics during three <span class="hlt">summer</span> <span class="hlt">storms</span> characterized by different rainfall magnitude in 2012 in a semi-arid catchment of northern China. The results showed that, in response to <span class="hlt">storm</span> events, nutrient dynamics displayed big variation in temporal trends of nutrient concentration and in nutrient concentration-flow discharge relationships. Nutrient concentrations had broader fluctuations during an extreme <span class="hlt">storm</span> than during lesser <span class="hlt">storms</span>, whereas the concentration ranges of the a moderate <span class="hlt">storm</span> were no broader than those of a smaller one. The different concentration fluctuations were caused by <span class="hlt">storm</span> magnitude and intensity coupled with the antecedent rainfall amount and cumulative nutrients. Correlation coefficients between nutrient concentrations and flow discharge varied from positive to negative for the three different events. There were no consistent hysteresis effects for the three different events, and no hysteresis effects were observed for any of the variables during the moderate <span class="hlt">storm</span> (E2). Our findings provide useful information for better understanding nutrient loss mechanisms during <span class="hlt">storm</span> events in semi-arid areas of a monsoon climate region.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/977796','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/977796"><span id="translatedtitle">Global lightning and severe <span class="hlt">storm</span> monitoring from GPS orbit</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Suszcynsky, D. M.; Jacobson, A. R.; Linford, J; Pongratz, M. B.; Light, T.; Shao, X.</p> <p>2004-01-01</p> <p> electrical activity within that cell as measured by the lightning flash rate. Williams [2001] has provided a review of experimental work that shows correlations between the total lightning flash rate and the fifth power of the radar cloud-top height (i.e. <span class="hlt">convective</span> strength) of individual thunder cells. More recently, Ushio et al., [2001] used a large statistical sampling of optical data from the Lightning Imaging Sensor (LIS) in conjunction with data provided by the Precipitation Radar (PR) aboard the Tropical Rainfall Monitoring Mission (TRMM) satellite to conclude that the total lightning flash rate increases exponentially with <span class="hlt">storm</span> height. Lightning activity levels have also been correlated to cloud ice content, a basic product of the <span class="hlt">convective</span> process. For example, Blyth et al. [2001] used the Thermal Microwave Imager (TMI) aboard the TRMM satellite to observe a decrease in the 37 and 85 GHz brightness temperatures of upwelling terrestrial radiation during increased lightning activity. This reduction in brightness temperature is believed to be the result of increased ice scattering in the mixed phase region of the cloud. Toracinta and Zipser [2001] have found similar relationships using the Optical Transient Detector (OTD) satellite instrument and the Special Sensor Microwave Imager (SSM/I) aboard the DMSP satellites.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19870003649&hterms=Apes&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3DApes','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19870003649&hterms=Apes&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3DApes"><span id="translatedtitle">A summary of research on mesoscale energetics of severe <span class="hlt">storm</span> environments</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Fuelberg, H. E.</p> <p>1985-01-01</p> <p>The goals of this research were to better understand interactions between areas of intense <span class="hlt">convection</span> and their surrounding mesoscale environments by using diagnostic budgets of kinetic (KE) and available potential energy (APE). Three cases of intense <span class="hlt">convection</span> were examined in detail. 1) Atmospheric Variability Experiments (AVE) carried out on 24 to 25 April 1975 were studied. Synoptic scale data at 3 to 6 hour intervals, contained two mesoscale <span class="hlt">convective</span> complexes (MCCs). Analyses included total KE budgets and budgets of divergent and rotational components of KE. 2) AVE-Severe Environmental <span class="hlt">Storms</span> and Mesoscale Experiments (SESAME)-4 carried out on 10 to 11 April 1979 were studied. Synotpic and meso alpha-scale data (250 km spacing, 3 hour intervals), contained the Red River Valley tornado outbreak. Analyses included total KE budgets (separate synoptic and mesoscale version), budgets for the divergent and rotational components, and the generation of APE by diabatic processes. 3) AVE-SESAME 5 studies were carried out on 20 to 31 May 1979. Synoptic and meso beta-scale data (75 km spacing, 1 1/2 to 3 hour intervals), contained a small MCC. Analyses include separate KE budgets for the synotic and meso beta-scales and a water vapor budget. Major findings of these investigations are: (1) The synoptic scale <span class="hlt">storm</span> environment contains energy conversions and transports that are comparable to those of mature midlatitude cyclones. (2) Energetic in the mesoscale <span class="hlt">storm</span> environment are often an order of magnitude larger than those in an undisturbed region. (3) Mesoscale wind maxima form in the upper troposphere on the poleward sides of <span class="hlt">convective</span> areas, whereas speeds decrease south of <span class="hlt">storm</span> regions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20060016396&hterms=convection&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3Dconvection','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20060016396&hterms=convection&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3Dconvection"><span id="translatedtitle">Overview of the <span class="hlt">Convection</span> and Moisture Experiment (CAMEX)</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Kakar, Ramesh; Goodman, Michael; Hood, robbie; Guillory, Anthony</p> <p>2006-01-01</p> <p>This paper presents an overview of the <span class="hlt">Convection</span> and Moisture Experiment (CAMEX), including the field operations, aircraft platforms and missions, instrumentation, and data acquired during 1998 and 2001 field campaigns. A total of eight tropical <span class="hlt">storms</span> and hurricanes were investigated during the CAMEX field campaigns including Bonnie, Danielle, Earl, and Georges during 1998 and Chantal, Erin, Gabrielle, and Humberto during 2001. Most of these <span class="hlt">storms</span> were sampled with aircraft over the open ocean, but Hurricanes Bonnie (1998), Georges (1998), and Gabrielle (2001) also provided opportunities to monitor landfalling impacts. A few of the <span class="hlt">storms</span> were sampled on multiple occasions during a course of several days. Most notable of these was Hurricane Humberto, which was sampled on three consecutive days during a cycle of both increasing and decreasing intensity change. Information collected for each of the eight CAMEX tropical <span class="hlt">storms</span> as well as the Tropical Rainfall Measuring Mission validation activities are accessible via the CAMEX Web site and archived at the National Aeronautics and Space Administration Marshall Space Flight Center.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/10688191','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/10688191"><span id="translatedtitle">Observation of moist <span class="hlt">convection</span> in Jupiter's atmosphere. Galileo Imaging Team</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Gierasch; Ingersoll; Banfield; Ewald; Helfenstein; Simon-Miller; Vasavada; Breneman; Senske</p> <p>2000-02-10</p> <p>The energy source driving Jupiter's active meteorology is not understood. There are two main candidates: a poorly understood internal heat source and sunlight. Here we report observations of an active <span class="hlt">storm</span> system possessing both lightning and condensation of water. The <span class="hlt">storm</span> has a vertical extent of at least 50 km and a length of about 4,000 km. Previous observations of lightning on Jupiter have revealed both its frequency of occurrence and its spatial distribution, but they did not permit analysis of the detailed cloud structure and its dynamics. The present observations reveal the <span class="hlt">storm</span> (on the day side of the planet) at the same location and within just a few hours of a lightning detection (on the night side). We estimate that the total vertical transport of heat by <span class="hlt">storms</span> like the one observed here is of the same order as the planet's internal heat source. We therefore conclude that moist <span class="hlt">convection</span>-similar to large clusters of thunderstorm cells on the Earth-is a dominant factor in converting heat flow into kinetic energy in the jovian atmosphere. PMID:10688191</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2008JHyd..363....1C&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2008JHyd..363....1C&link_type=ABSTRACT"><span id="translatedtitle">An operational approach for classifying <span class="hlt">storms</span> in real-time radar rainfall estimation</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Chumchean, Siriluk; Seed, Alan; Sharma, Ashish</p> <p>2008-12-01</p> <p>SummaryThis paper presents an operational approach to integrate a <span class="hlt">storm</span> classification method into a real-time radar rainfall estimation. A minor modification of a texturing classification algorithm proposed by Steiner et al. [Steiner, M., Houze Jr., R.A., Yuter, S.E., 1995. Climatological characterisation of three-dimensional <span class="hlt">storm</span> structure from operational radar and rain gauge data. J. Appl. Meteorol. 34, 1978-2007] that can classify each pixel in the radar image as stratiform or <span class="hlt">convective</span> is used to classify the instantaneous reflectivity field into <span class="hlt">convective</span> and stratiform components. A method to derive the climatological Z-R relations for <span class="hlt">convective</span> and stratiform rainfall is proposed. Vertical profiles of reflectivity (VPRs) are used to verify the accuracy of the <span class="hlt">storm</span> classification. An alternative method for verification of a <span class="hlt">storm</span> classification scheme based on differences between probability distribution functions of rain gauge rainfall of the two rainfall categories is also presented. A 6-month record of radar and rain gauge rainfall for Sydney, Australia for November 2000-April 2001 is used for training and rainfall events during February 2007-March 2007 are used to evaluate the efficiency and applicability of the proposed methods. The results show that the proposed operational approach for classifying <span class="hlt">storms</span> in real-time radar rainfall estimates reduces RMSE between radar and rain gauge rainfall from 4.63 to 4.30 mm h -1 and from 5.31 to 5.01 mm h -1 for the training and verification periods compared to the case where the rainfall is assumed to have a single Z-R relationship.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/5028818','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/5028818"><span id="translatedtitle">Distribution of auroral precipitation at midnight during a magnetic <span class="hlt">storm</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Sandahl, I.; Eliasson, L.; Pellinen-Wannberg, A. ); Rostoker, G. ); Block, L.P. ); Erlandson, R.E. ); Friis-Christensen, E. ); Jacobsen, B. ); Luehr, H. ); Murphree, J.S. )</p> <p>1990-05-01</p> <p>On the night of November 4, 1986, a very complex precipitation pattern was observed by Viking in the magnetic midnight sector over Scandinavia and Svalbard. The pass took place during a magnetic <span class="hlt">storm</span>, and during substorm recovery phase. Going from north to south, the satellite first encountered a plasma region of BPS-type (name derived from boundary plasma sheet) and then a region of CPS type (derived from central plasma sheet). Then, however, a new region of BPS-type was traversed. The quite intense, most equatorward aurora corresponded to a plasma region which was not of ordinary CPS type but contained sharp quasi-monoenergetic peaks. The high-latitude midnight sector was totally dominated by eastward <span class="hlt">convection</span>. The Harang discontinuity had passed northern Scandinavia the first time as early as 17 to 20 MLT, more than three house before the Viking pass. It is suggested that the particle precipitation pattern and the general shape of the aurora as observed by the Viking imager can be explained in a natural way by the <span class="hlt">convection</span> pattern. The northernmost BPS- and CPS-type regions originated in the morningside <span class="hlt">convection</span> cell, while the more equatorward population of BPS type had drifted in from the eveningside. The interpretation is supported by ground-based measurements by EISCAT and magnetometers.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013EGUGA..15.5510B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013EGUGA..15.5510B"><span id="translatedtitle">Role of model resolution and microphysical properties in simulating flash flood induce <span class="hlt">storms</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bartsotas, Nikolaos; Solomos, Stavros; Nikolopoulos, Efthymios I.; Anagnostou, Emmanouil; Kallos, George</p> <p>2013-04-01</p> <p>Flash flood induce <span class="hlt">storms</span> are mainly of <span class="hlt">convective</span> nature and develop at small space and short time scales making their predictability a particularly challenging task. The tremendous societal and economical impact of this hazard necessitates the development of accurate forecasting systems in order to advance warnings and mitigate the risk. To be able to develop a forecasting system that can accurately represent flash flood <span class="hlt">storms</span>, we need to understand the key elements that control the generation and evolution of this type of events. This study examines the effect of topographic representation, model grid resolution and cloud microphysical properties in simulating three major flash flood <span class="hlt">storms</span> that occurred in Northern Italy. To simulate those heavy precipitation events, the high-resolution integrated atmospheric model RAMS / ICLAMS was used with grid resolutions of 250 m, in order to properly resolve the complex physical processes and <span class="hlt">convective</span> activity. In addition, a high resolution topography dataset of 3 arcsec from the NASA SRTM mission was implemented in the model. The sensitivity of microphysical properties and aerosol cloud interactions towards <span class="hlt">convection</span> and precipitation over the area were examined through various model setups and simulations. The specific properties proved to play a significant role in the correct estimation of spatial distribution and quantity of precipitation, as indicated from the comparison of the model outputs with bias adjusted radar data.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFMSM51D..05B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFMSM51D..05B"><span id="translatedtitle">Comparison of auroral latitude <span class="hlt">convection</span> to central polar cap <span class="hlt">convection</span>. (Invited)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bristow, W. A.; Amata, E.</p> <p>2013-12-01</p> <p>The SuperDARN radar at McMurdo station has been providing <span class="hlt">convection</span> observations in the central polar cap since January 2010. The Antarctic magnetic pole lies in the center of the radar field of view at about 1000 km range, which is optimum for <span class="hlt">convection</span> observations. A new pair of SuperDARN radars was constructed in the Antarctic <span class="hlt">summer</span> of 2012/2013, which add highly complimentary fields of view. The radars, one located at the Italian station at Dome-C, and one located at the US South Pole Station, are directed into a region directly equatorward of the McMurdo field of view. The radars came on line in late January 2013 and are producing excellent <span class="hlt">convection</span> observations. This paper presents initial results combining the three radar's <span class="hlt">convection</span> observations. Intervals when the IMF clock angle was between 135 and 225 for periods of more than an hour were selected for study. Just under 50 hours of observations met this criteria since the radars began operation. <span class="hlt">Convection</span> vectors were formed using the standard SuperDARN algorithm [Ruohoniemi and Baker, 1998] and the auroral-zone flows were compared to those in the central polar cap. Central polar cap flows are typically spatially uniform though highly variable in time, even though the lower latitude observations were spatially structured. The central polar cap average flow velocity is less than 500 m/s, though it often exceeds 1000 m/s. Conditions that lead to the high-speed flow are presented. In addition, correlation with the IMF and solar wind are presented. At times the correlation exceeds 80% while at others it is near zero.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19960048434','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19960048434"><span id="translatedtitle">The Gravity Wave Response Above Deep <span class="hlt">Convection</span> in a Squall Line Simulation</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Alexander, M. J.; Holton, J. R.; Durran, D. R.</p> <p>1995-01-01</p> <p>High-frequency gravity waves generated by <span class="hlt">convective</span> <span class="hlt">storms</span> likely play an important role in the general circulation of the middle atmosphere. Yet little is known about waves from this source. This work utilizes a fully compressible, nonlinear, numerical, two-dimensional simulation of a midlatitude squall line to study vertically propagating waves generated by deep <span class="hlt">convection</span>. The model includes a deep stratosphere layer with high enough resolution to characterize the wave motions at these altitudes. A spectral analysis of the stratospheric waves provides an understanding of the necessary characteristics of the spectrum for future studies of their effects on the middle atmosphere in realistic mean wind scenarios. The wave spectrum also displays specific characteristics that point to the physical mechanisms within the <span class="hlt">storm</span> responsible for their forcing. Understanding these forcing mechanisms and the properties of the <span class="hlt">storm</span> and atmosphere that control them are crucial first steps toward developing a parameterization of waves from this source. The simulation also provides a description of some observable signatures of <span class="hlt">convectively</span> generated waves, which may promote observational verification of these results and help tie any such observations to their <span class="hlt">convective</span> source.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19880009668','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19880009668"><span id="translatedtitle">Suggested severe local <span class="hlt">storm</span> operational scenario for GOES I-M</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Shenk, William E.; Mosher, Fredrick</p> <p>1987-01-01</p> <p>The GOES I-M satellite system is expected to provide continuous high resolution estimates of temperature and moisture profiles, winds from cloud motions, surface temperature, cloud properties, and precipitation for severe local <span class="hlt">storm</span> and tropical cyclone events. The suggested operational schedule for the GOES I-M satellite emphasizes the observation frequencies, spatial coverage, spectral bands, etc. for the GOES I-M imager and sounder instruments that are expected to optimize the determination of the relevant meteorological parameters. During severe local <span class="hlt">storm</span> events, the imager would be programmed to perform high frequency imaging (less than or= 3.5 min) for determining winds from cloud motions and for monitoring severe <span class="hlt">convection</span>. In addition, the sounder would provide temperature and moisture profiles every hour over a 3000 X 3000 km domain during the antecedent stage or over a 1000 X 1000 km area every 10 minutes during the mature <span class="hlt">storm</span> stage.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/6805478','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/6805478"><span id="translatedtitle">Bracing for the geomagnetic <span class="hlt">storms</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Kappenman, J.G. ); Albertson, V.D. )</p> <p>1990-03-01</p> <p>The authors discuss the impact of geomagnetic <span class="hlt">storms</span> on utility transmission networks. The effects of a recent <span class="hlt">storm</span> on the Hydro-Quebec transmission system are described in detail. Research into geomagnetic disturbance prediction is discussed. In coming months, geomagnetic field activity will be high as it builds toward a peak, the 22nd since reliable records of the phenomenon began in the mid-1700s. The peaks come in roughly 11-year cycles, and the next is expected later this year or early in 1991. The solar activity has so far risen at one of the fastest rates ever recorded, and solar forecasters expect cycle 22 to have unusually high activity levels.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19780010682','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19780010682"><span id="translatedtitle">National Severe <span class="hlt">Storms</span> Forecast Center</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p></p> <p>1977-01-01</p> <p>The principal mission of the National Severe <span class="hlt">Storms</span> Forecast Center (NSSFC) is to maintain a continuous watch of weather developments that are capable of producing severe local <span class="hlt">storms</span>, including tornadoes, and to prepare and issue messages designated as either Weather Outlooks or Tornado or Severe Thunderstorm Watches for dissemination to the public and aviation services. In addition to its assigned responsibility at the national level, the NSSFC is involved in a number of programs at the regional and local levels. Subsequent subsections and paragraphs describe the NSSFC, its users, inputs, outputs, interfaces, capabilities, workload, problem areas, and future plans in more detail.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20000024980&hterms=fellowship&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dfellowship','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20000024980&hterms=fellowship&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dfellowship"><span id="translatedtitle">IISME <span class="hlt">Summer</span> Fellowship Program</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p></p> <p>1998-01-01</p> <p>During the <span class="hlt">summer</span> of 1997, NASA-Ames scientists served as mentors to six teachers who worked as IISME (Industry Initiatives for Science and Math Education) Teacher Fellows over the <span class="hlt">summer</span>. These six teachers were among 91 IISME Teacher Fellows working at various corporate, government agency, and university sites throughout the San Francisco Bay Area. These NASA-Ames fellowship positions are described in brief. One requirement of the IISME <span class="hlt">Summer</span> Fellowship program is that teachers develop a personal Action Plan for classroom transfer. These Action Plans are published in abstract form in an annual catalog. I have also attached the abstracts of NASA-Ames teachers.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19790023714','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19790023714"><span id="translatedtitle"><span class="hlt">Convective</span> rainfall estimation from digital GOES-1 infrared data</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Sickler, G. L.; Thompson, A. H.</p> <p>1979-01-01</p> <p>An investigation was conducted to determine the feasibility of developing and objective technique for estimating <span class="hlt">convective</span> rainfall from digital GOES-1 infrared data. The study area was a 240 km by 240 km box centered on College Station, Texas (Texas A and M University). The Scofield and Oliver (1977) rainfall estimation scheme was adapted and used with the digital geostationary satellite data. The concept of enhancement curves with respect to rainfall approximation is discussed. Raingage rainfall analyses and satellite-derived rainfall estimation analyses were compared. The correlation for the station data pairs (observed versus estimated rainfall amounts) for the <span class="hlt">convective</span> portion of the <span class="hlt">storm</span> was 0.92. It was demonstrated that a fairly accurate objective rainfall technique using digital geostationary infrared satellite data is feasible. The rawinsonde and some synoptic data that were used in this investigation came from NASA's Atmospheric Variability Experiment, AVE 7.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AGUFM.A33G0232M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AGUFM.A33G0232M"><span id="translatedtitle">Multi-Sensor Analysis of Overshooting Tops in Tornadic <span class="hlt">Storms</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Magee, N. B.; Goldberg, R.; Hartline, M.</p> <p>2012-12-01</p> <p>The disastrous 2011 tornado season focused much attention on the ~75% false alarm rate for NWS-issued tornado warnings. Warnings are correctly issued on ~80% of verified tornados, but the false alarm rate has plateaued at near 75%. Any additional clues that may signal tornadogenesis would be of great benefit to the public welfare. We have performed statistical analyses of the structure and time-evolution of <span class="hlt">convective</span> overshooting tops for tornadic <span class="hlt">storms</span> occurring in the continental United States since 2006. An amalgam of case studies and theory has long suggested that overshooting tops may often collapse just prior to the onset of tornado touchdown. Our new results suggest that this view is supported by a broad set of new statistical evidence. Our approach to the analysis makes use of a high resolution, multi-sensor data set, and seeks to gather statistics on a large set of <span class="hlt">storms</span>. Records of 88-D NEXRAD radar Enhanced-Resolution Echo Tops (product available since 2009) have been analyzed for an hour prior to and following touchdown of all EF1 and stronger <span class="hlt">storms</span>. In addition, a coincidence search has been performed for the NASA A-Train satellite suite and tornadic events since 2006. Although the paths of the polar-orbiting satellites do not aid in analyses of temporal <span class="hlt">storm</span>-top evolution, Aqua-MODIS, CALIPSO, and Cloud-Sat have provided a detailed structural picture of overshooting tops in tornadic and non-tornadic supercell thunderstorms. 250 m resolution AQUA-MODIS image at 1950Z on 4/27/2011, color-enhanced to emphasize overshooting tops during tornado outbreak.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li class="active"><span>21</span></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_21 --> <div id="page_22" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li class="active"><span>22</span></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="421"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.youtube.com/watch?v=VKgKYTiumpg','SCIGOVIMAGE-NASA'); return false;" href="http://www.youtube.com/watch?v=VKgKYTiumpg"><span id="translatedtitle">GPM Sees Powerful <span class="hlt">Storms</span> in Tropical <span class="hlt">Storm</span> Hermine</span></a></p> <p><a target="_blank" href="http://www.nasa.gov/multimedia/videogallery/index.html">NASA Video Gallery</a></p> <p></p> <p></p> <p>This is a 3-D animated flyby of Tropical <span class="hlt">Storm</span> Hermine created using radar data from the GPM core satellite. On Aug. 31 at 4 p.m. EDT GPM found rainfall occurring at a rate of over 9.9 inches (251 ...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1998APS..DFD..DI01R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1998APS..DFD..DI01R"><span id="translatedtitle">Natural <span class="hlt">convective</span> mixing flows</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ramos, Eduardo; de La Cruz, Luis; del Castillo, Luis</p> <p>1998-11-01</p> <p>Natural <span class="hlt">convective</span> mixing flows. Eduardo Ramos and Luis M. de La Cruz, National University of Mexico and Luis Del Castillo San Luis Potosi University. The possibility of mixing a fluid with a natural <span class="hlt">convective</span> flow is analysed by solving numerically the mass, momentum and energy equations in a cubic container. Two opposite vertical walls of the container are assumed to have temperatures that oscillate as functions of time. The phase of the oscillations is chosen in such a way that alternating corrotating vortices are formed in the cavity. The mixing efficiency of this kind of flow is examined with a Lagrangian tracking technique. This work was partially financed by CONACyT-Mexico project number GE0044</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JGRD..120.3354L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JGRD..120.3354L"><span id="translatedtitle">Large charge moment change lightning on 31 May to 1 June 2013, including the El Reno tornadic <span class="hlt">storm</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lang, Timothy J.; Cummer, Steven A.; Petersen, Danyal; Flores-Rivera, Lizxandra; Lyons, Walter A.; MacGorman, Donald; Beasley, William</p> <p>2015-04-01</p> <p>On 31 May 2013, a line of severe tornadic thunderstorms (the El Reno event) developed during the local afternoon in central Oklahoma, USA. Within range of the Oklahoma Lightning Mapping Array, the evolution of the event can be separated into three distinct periods: an Early period (before 02:00 UTC on 1 June) when the <span class="hlt">storm</span> consisted of discrete supercells, a Middle period (02:00-05:00 UTC) when the <span class="hlt">convection</span> began merging into a linear feature and stratiform precipitation developed, and a Late period (after 05:00 UTC) featuring a mature mesoscale <span class="hlt">convective</span> system (MCS). Each of these periods demonstrated distinct patterns in the large (>100 C km) charge moment change (CMC) lightning that was produced. During the Early period, large-CMC positive cloud-to-ground (+CG) lightning was produced in the <span class="hlt">convective</span> cores of supercells. These flashes were small in area (typically <500 km2) and were commonly associated with a sloping midlevel positive charge region in the echo overhang on the <span class="hlt">storm</span>'s forward flank. The Middle period featured a population of larger +CMCs (>500 km2, >300 C km) in the developing stratiform, similar to typical sprite-parent lightning in MCSs. During the Late period, <span class="hlt">convective</span> large CMC +CGs ceased and instead large-CMC negative CGs were produced in and near the MCS <span class="hlt">convection</span>. These flashes neutralized charge both in <span class="hlt">convection</span> as well as in adjacent stratiform and anvil precipitation. The results suggest that the CMC metric has potential applications for studying tropospheric weather.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFM.A53D3249T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFM.A53D3249T"><span id="translatedtitle">Impacts of a Fire Smoke Plume on Deep <span class="hlt">Convective</span> Clouds Observed during DC3</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Takeishi, A.; Storelvmo, T.; Zagar, M.</p> <p>2014-12-01</p> <p>While the ability of aerosols to act as cloud condensation nuclei (CCN) and ice nuclei (IN) is well recognized, the effects of changing aerosol number concentrations on <span class="hlt">convective</span> clouds have only been studied extensively in recent years. As deep <span class="hlt">convective</span> clouds can produce heavy precipitation and may sometimes bring severe damages, especially in the tropics, we need to understand the changes in the <span class="hlt">convective</span> systems that could stem from aerosol perturbations. By perturbing <span class="hlt">convective</span> clouds, it has also been proposed that aerosols can affect large-scale climate. According to the <span class="hlt">convective</span> invigoration mechanism, an increase in the aerosol concentration could lead to a larger amount of rainfall and higher vertical velocities in <span class="hlt">convective</span> clouds, due to an increase in the latent heat release aloft. With some of the satellite observations supporting this mechanism, it is necessary to understand how sensitive the model simulations actually are to aerosol perturbations. This study uses the Weather Research and Forecasting (WRF) model as a cloud-resolving model to reproduce deep <span class="hlt">convective</span> clouds observed during the Deep <span class="hlt">Convective</span> Clouds and Chemistry (DC3) field campaign. The <span class="hlt">convective</span> cloud of our interest was observed in northeastern Colorado on June 22nd in 2012, with a plume of forest fire smoke flowing into its core. Compared to other <span class="hlt">convective</span> cells observed in the same area on different days, our aircraft data analysis shows that the <span class="hlt">convective</span> cloud in question included more organic aerosols and more CCN. These indicate the influence of the biomass burning. We compare the results from simulations with different microphysics schemes and different cloud or ice number concentrations. These sensitivity tests tell us how different the amount and the pattern of precipitation would have been if the aerosol concentration had been higher or lower on that day. Both the sensitivity to aerosol perturbation and the reproducibility of the <span class="hlt">storm</span> are shown to highly</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/1171131','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/1171131"><span id="translatedtitle">The relationship between large-scale and <span class="hlt">convective</span> states in the tropics - Towards an improved representation of <span class="hlt">convection</span> in large-scale models</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Jakob, Christian</p> <p>2015-02-26</p> <p>This report summarises an investigation into the relationship of tropical thunderstorms to the atmospheric conditions they are embedded in. The study is based on the use of radar observations at the Atmospheric Radiation Measurement site in Darwin run under the auspices of the DOE Atmospheric Systems Research program. Linking the larger scales of the atmosphere with the smaller scales of thunderstorms is crucial for the development of the representation of thunderstorms in weather and climate models, which is carried out by a process termed parametrisation. Through the analysis of radar and wind profiler observations the project made several fundamental discoveries about tropical <span class="hlt">storms</span> and quantified the relationship of the occurrence and intensity of these <span class="hlt">storms</span> to the large-scale atmosphere. We were able to show that the rainfall averaged over an area the size of a typical climate model grid-box is largely controlled by the number of <span class="hlt">storms</span> in the area, and less so by the <span class="hlt">storm</span> intensity. This allows us to completely rethink the way we represent such <span class="hlt">storms</span> in climate models. We also found that <span class="hlt">storms</span> occur in three distinct categories based on their depth and that the transition between these categories is strongly related to the larger scale dynamical features of the atmosphere more so than its thermodynamic state. Finally, we used our observational findings to test and refine a new approach to cumulus parametrisation which relies on the stochastic modelling of the area covered by different <span class="hlt">convective</span> cloud types.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/5311562','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/5311562"><span id="translatedtitle">DE 2 observations of disturbances in the upper atmosphere during a geomagnetic <span class="hlt">storm</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Miller, N.J.; Brace, L.H.; Spencer, N.W. ); Carignan, G.R. )</p> <p>1990-12-01</p> <p>Data taken in the dusk sector of the mid-latitude thermosphere at 275-450 km by instruments on board Dynamics Explorer 2 in polar orbit are used to examine the response of the ionosphere- thermosphere system during a geomagnetic <span class="hlt">storm</span>. The results represent the first comparison of nearly simultaneous measurements of <span class="hlt">storm</span> disturbances in dc electric fields, zonal ion <span class="hlt">convection</span>, zonal winds, gas composition and temperature, and electron density and temperature, at different seasons in a common local time sector. The <span class="hlt">storm</span> commenced on November 24, 1982, during the interaction of a solar wind disturbance with the geomagnetic field while the north-south component of the interplanetary magnetic field, B{sub z}, was northward. The <span class="hlt">storm</span> main phase began while B{sub z} was turning southward. <span class="hlt">Storm</span>-induced variations in meridional de electric fields, neutral composition, and N{sub e} were stronger and spread farther equatorward in the winter hemisphere. Westward ion <span class="hlt">convection</span> was intense enough to produce westward winds of 600 m s{sup {minus} 1} via ion drag in the winter hemisphere. Frictional heating was sufficient to elevate ion temperatures above electron temperatures in both seasons and to produce large chemical losses of O{sup +} by increasing the rate of O{sup +} loss via ion-atom interchange. Part of the chemical loss of O{sup +} was compensated by upward flow of O{sup +} as the ion scale height adjusted to the increasing ion temperatures. In this <span class="hlt">storm</span>, frictional heating was an important subauroral heat source equatorward to at least 53{degree} invariant latitude.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2001JGR...10624493L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2001JGR...10624493L"><span id="translatedtitle">Coexistence of ionospheric positive and negative <span class="hlt">storm</span> phases under northern winter conditions: A case study</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lu, G.; Richmond, A. D.; Roble, R. G.; Emery, B. A.</p> <p>2001-11-01</p> <p>The response of the thermosphere and ionosphere to the famous January 10, 1997, geomagnetic <span class="hlt">storm</span> is simulated using the thermosphere-ionosphere-electrodynamics general circulation model with realistic, time-dependent distributions of ionospheric <span class="hlt">convection</span> and auroral precipitation as inputs. The simulation results show a dominant positive <span class="hlt">storm</span> phase of increased F layer electron density over much of the northern winter hemisphere, but a negative <span class="hlt">storm</span> phase with reduced electron density at middle and low latitudes is also evident in the simulation. The coexistence of both positive and negative <span class="hlt">storm</span> phases is a result of the complex dynamical and chemical interactions between charged particles and neutral gases. The impulsive magnetospheric energy inputs via auroral precipitation and Joule heating generate traveling atmospheric and ionospheric disturbances (TADs and TIDs) which propagate from the northern auroral zone to lower latitudes and penetrate well into the Southern Hemisphere. The simulation results demonstrate that positive <span class="hlt">storm</span> phases are caused primarily by enhanced auroral precipitation over high latitudes and by TIDs at middle and low latitudes. Globally speaking, composition changes in terms of enhancements in the N2/O ratio are mainly responsible for negative <span class="hlt">storm</span> effects. However, although there is some correlation between increases in N2/O and decreases in the F layer critical frequency f0F2 in the winter hemisphere during the <span class="hlt">storm</span> main phase and early recovery phase, the overall changes in f0F2 are also determined by other processes, such as the ionization production associated with enhanced auroral precipitation and the variations associated with TIDs. In the low to middle-latitude region changes in f0F2 approximately anticorrelate with changes at the height of the F layer electron density peak (e.g., hmF2) at 70°W during the <span class="hlt">storm</span> main phase as well as its early recovery phase. This is attributed in part to the relation that exists</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFMSA23E..02K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFMSA23E..02K"><span id="translatedtitle"><span class="hlt">Storm</span>-time Large-Scale Birkeland Currents: Salient Dynamics in Grand Challenge Events</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Korth, H.; Anderson, B. J.; Waters, C. L.; Barnes, R. J.</p> <p>2015-12-01</p> <p>The Active Magnetosphere and Planetary Electrodynamics Response Experiment (AMPERE) provides continuous global observations of Birkeland currents on a 10 minute cadence. During geomagnetic <span class="hlt">storms</span>, currents intensify to over 15 MA, are dynamic both in intensity and distribution, and exhibit features not discernible in statistical analyses. For all of the subject grand challenge <span class="hlt">storms</span>, AMPERE data reveal a number of novel phenomena illustrating the profound dynamics of the <span class="hlt">storm</span>-time system. <span class="hlt">Storm</span>-time onsets associated with shock arrivals are often very prompt and lead to dramatic surges in total current from 1 MA to over 5 MA in less than 20 minutes. The current surges occur predominantly on the dayside at high latitudes prior to any ring current or auroral expansions, indicating that neutral density upwelling is often driven independently of ring current or auroral zone intensifications. Rapid reconfigurations of the currents with IMF BY reversals within the sheath structures of coronal mass ejections (CMEs) are also common. This implies that <span class="hlt">convection</span> of ionospheric density patches over the polar cap may be quite complex, particularly during the early phase of geomagnetic <span class="hlt">storms</span> related to the CME sheath passage. The 3 September 2012 <span class="hlt">storm</span> exhibited intense driving with classic quasi-stable Region 1 and 2 currents spanning 55 to 70 degrees magnetic latitude for over 10 hours at the beginning of the day, corresponding to stable southward IMF prior to shock arrival at noon on that day. The shock arrival and IMF southward intensification led to further expansion of the currents below 50 degrees magnetic latitude and to episodic surges in currents on the nightside, which is unique to <span class="hlt">storms</span>. The resulting current structure showed multiple large-scale alternations in downward-upward-downward-upward direction that often occurs during intense, sustained driving during strong <span class="hlt">storms</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://eric.ed.gov/?q=summer+AND+internships&pg=7&id=EJ145960','ERIC'); return false;" href="http://eric.ed.gov/?q=summer+AND+internships&pg=7&id=EJ145960"><span id="translatedtitle">The Purdue <span class="hlt">Summer</span> Internship</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Hamilton, William; And Others</p> <p>1976-01-01</p> <p>Describes a program in which college agricultural education majors between their junior and senior years are placed with vocational agriculture teachers to gain experience in conducting a <span class="hlt">summer</span> vocational agriculture program. (HD)</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/823564','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/823564"><span id="translatedtitle">Chemical Physics <span class="hlt">Summer</span> School</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p></p> <p>2002-06-28</p> <p>The Gordon Research Conference (GRC) on Chemical Physics <span class="hlt">Summer</span> School was held at Roger Williams University, Bristol, RI. Emphasis was placed on current unpublished research and discussion of the future target areas in this field.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://eric.ed.gov/?q=Beavers&pg=3&id=EJ481324','ERIC'); return false;" href="http://eric.ed.gov/?q=Beavers&pg=3&id=EJ481324"><span id="translatedtitle"><span class="hlt">Summer</span> Success Story.</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Matika, Francis W.</p> <p>1994-01-01</p> <p>Pennsylvania's Beaver Valley Intermediate Unit built a collaborative 2-week <span class="hlt">summer</span> academy, opening it to students in the other 14 school districts in the county. Cooperation among all the districts provided students opportunities for expanded learning experiences. (MLF)</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://american.redcross.org/site/DocServer/watersafety0609.pdf?docID=735','NIH-MEDLINEPLUS'); return false;" href="http://american.redcross.org/site/DocServer/watersafety0609.pdf?docID=735"><span id="translatedtitle"><span class="hlt">Summer</span> Water Safety Guide</span></a></p> <p><a target="_blank" href="http://medlineplus.gov/">MedlinePlus</a></p> <p></p> <p></p> <p>... this flyer at your pool, community center and beach bulletin boards. • Visit RedCross. org for more swimming ... GREAT <span class="hlt">SUMMER</span> SAVINGS AT RED CROSS STORE! VINTAGE BEACH TOWEL ALL RED CROSS GEAR USE DISCOUNT CODE: ...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19930010898','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19930010898"><span id="translatedtitle">Electrification in winter <span class="hlt">storms</span> and the analysis of thunderstorm overflight data</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Brook, Marx</p> <p>1993-01-01</p> <p>We have been focusing our study of electrification in winter <span class="hlt">storms</span> on the lightning initiation process, making inferences about the magnitude of the electric fields from the initial pulses associated with breakdown, i.e., with the formation of the initial streamers. The essence of the most significant finding is as follows: (1) initial breakdown radiation pulses from stepped leaders prior to the first return stroke are very large, reaching values of 20-30 Volts/meter, comparable to return stroke radiation; and (2) the duration of the stepped leader, from the initial detectable radiation pulse to the return stroke onset, is very-short-ranging from a minimum 1.5 ms to a maximum of 4.5 ms. This past <span class="hlt">summer</span> (June-August of 1991) we participated in the CAPE program at the Kennedy Space Center in order to acquire data on stepped leaders in <span class="hlt">summer</span> <span class="hlt">storms</span> with the same equipment used to get the winter <span class="hlt">storm</span> data. We discovered that the vigorous leaders seen in winter so frequently were present in <span class="hlt">summer</span> <span class="hlt">storms</span>, although not as large in amplitude and certainly not as frequent.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://eric.ed.gov/?q=%22Sea+side%22+OR+coastline&pg=2&id=EJ237549','ERIC'); return false;" href="http://eric.ed.gov/?q=%22Sea+side%22+OR+coastline&pg=2&id=EJ237549"><span id="translatedtitle">Templates of Change: <span class="hlt">Storms</span> and Shoreline Hazards.</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Dolan, Robert; Hayden, Bruce</p> <p>1980-01-01</p> <p>Presents results of research designed to assess and predict the <span class="hlt">storm</span>-related hazards of living on the coast. Findings suggest that certain sections of coastline are more vulnerable than others to <span class="hlt">storm</span> damage. (WB)</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.youtube.com/watch?v=hwuz9oGroQI','SCIGOVIMAGE-NASA'); return false;" href="http://www.youtube.com/watch?v=hwuz9oGroQI"><span id="translatedtitle">Tropical <span class="hlt">Storm</span> Debby Moves into Atlantic</span></a></p> <p><a target="_blank" href="http://www.nasa.gov/multimedia/videogallery/index.html">NASA Video Gallery</a></p> <p></p> <p></p> <p>An animation of satellite observations shows the progression of Tropical <span class="hlt">Storm</span> Debby from June 25-27, 2012. The animation shows that Tropical <span class="hlt">Storm</span> Debby's center move from the northeastern Gulf of...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.youtube.com/watch?v=23WL_QDHaAA','SCIGOVIMAGE-NASA'); return false;" href="http://www.youtube.com/watch?v=23WL_QDHaAA"><span id="translatedtitle">Satellite View of 2 Trop. <span class="hlt">Storms</span></span></a></p> <p><a target="_blank" href="http://www.nasa.gov/multimedia/videogallery/index.html">NASA Video Gallery</a></p> <p></p> <p></p> <p>System 98L exploded into Tropical <span class="hlt">Storm</span> Irene on Saturday, August 20. This GOES-13 Video shows Tropical <span class="hlt">Storm</span> Harvey making landfall in Belize (just beneath the Yucatan Peninsula) and moving into t...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/1008260','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/1008260"><span id="translatedtitle">Impact of anthropogenic aerosols on Indian <span class="hlt">summer</span> monsoon</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Wang, Chien; Kim, Dongchul; Ekman, Annica; Barth, Mary; Rasch, Philip J.</p> <p>2009-11-05</p> <p>Using an interactive aerosol-climate model we find that absorbing anthropogenic aerosols, whether coexisting with scattering aerosols or not, can significantly affect the Indian <span class="hlt">summer</span> monsoon system. We also show that the influence is reflected in a perturbation to the moist static energy in the sub-cloud layer, initiated as a heating by absorbing aerosols to the planetary boundary layer. The perturbation appears mostly over land, extending from just north of the Arabian Sea to northern India along the southern slope of the Tibetan Plateau. As a result, during the <span class="hlt">summer</span> monsoon season, modeled <span class="hlt">convective</span> precipitation experiences a clear northward shift, coincidently in agreement with observed monsoon precipitation changes in recent decades particularly during the onset season. We demonstrate that the sub-cloud layer moist static energy is a useful quantity for determining the impact of aerosols on the northward extent and to a certain degree the strength of monsoon <span class="hlt">convection</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2012AGUFM.A43K..03V&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2012AGUFM.A43K..03V&link_type=ABSTRACT"><span id="translatedtitle">Microphysical Contributions to the Latent Heating Structures of Midlatitude and Tropical <span class="hlt">Storms</span> and Feedbacks to <span class="hlt">Storm</span> Organization</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>van den Heever, S. C.; Saleeby, S. M.; Herbener, S.; Storer, R. L.; Seigel, R. B.; Igel, A. L.; Sheffield, A. M.; McGee, C. J.; Igel, M. R.; Grant, L. D.; Clavner, M.; L'Ecuyer, T.; Berg, W. K.</p> <p>2012-12-01</p> <p>Latent heating associated with phase changes is a fundamental cloud process, and is influenced by both the microphysical and dynamical characteristics of the cloud system. As such, the structure of latent heating tends to be a function of the vertical profile, as well as of cloud type. Furthermore, changes to the latent heating can induce significant changes to the intensity of the cloud system, which in turn can have feedbacks on the microphysical processes and precipitation production of such <span class="hlt">storms</span>. In spite of the importance of latent heating across a broad range of cloud systems, few direct measurements of this field are made routinely on a global basis. Nearly all current large-scale retrieval schemes depend heavily on some form of cloud resolving model simulations. With the development and design of future satellite and radar systems, it is hoped that more direct measurements of latent heat may become possible. However, in the meantime, it appears that one of our most appropriate tools to examine latent heating is cloud resolving models with sophisticated cloud microphysical schemes. The goal of the research to be presented is to examine the variations in the magnitude and distribution of latent heating across a range of different <span class="hlt">storm</span> types, the role of different microphysical processes in explaining such variations, and the feedbacks between latent heating and dynamics in the organization of such systems. In particular, these characteristics will be examined for extratropical cyclones, squall lines and deep tropical <span class="hlt">convection</span>. The goal will be achieved by examining a suite of numerical simulations of these <span class="hlt">storm</span> systems conducted using the Regional Atmospheric Modeling System (RAMS). Recent developments to the model code allow for the evaluation of the contributions made by each microphysical process to the latent heating throughout the model domain. Insights into the importance of different microphysical processes in explaining the vertical and</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20110008660','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20110008660"><span id="translatedtitle">Analysis of Summertime <span class="hlt">Convective</span> Initiation in Central Alabama Using the Land Information System</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>James, Robert S.; Case, Jonathan L.; Molthan, Andrew L.; Jedlovec, Gary J.</p> <p>2011-01-01</p> <p>During the <span class="hlt">summer</span> months in the southeastern United States, <span class="hlt">convective</span> initiation presents a frequent challenge to operational forecasters. Thunderstorm development has traditionally been referred to as random due to their disorganized, sporadic appearance and lack of atmospheric forcing. Horizontal variations in land surface characteristics such as soil moisture, soil type, land and vegetation cover could possibly be a focus mechanism for afternoon <span class="hlt">convection</span> during the <span class="hlt">summer</span> months. The NASA Land Information System (LIS) provides a stand-alone land surface modeling framework that incorporates these varying soil and vegetation properties, antecedent precipitation, and atmospheric forcing to represent the soil state at high resolution. The use of LIS as a diagnostic tool may help forecasters to identify boundaries in land surface characteristics that could correlate to favored regions of <span class="hlt">convection</span> initiation. The NASA Shortterm Prediction Research and Transition (SPoRT) team has been collaborating with the National Weather Service Office in Birmingham, AL to help incorporate LIS products into their operational forecasting methods. This paper highlights selected <span class="hlt">convective</span> case dates from <span class="hlt">summer</span> 2009 when synoptic forcing was weak, and identifies any boundaries in land surface characteristics that may have contributed to <span class="hlt">convective</span> initiation. The LIS output depicts the effects of increased sensible heat flux from urban areas on the development of <span class="hlt">convection</span>, as well as <span class="hlt">convection</span> along gradients in land surface characteristics and surface sensible and latent heat fluxes. These features may promote mesoscale circulations and/or feedback processes that can either enhance or inhibit <span class="hlt">convection</span>. With this output previously unavailable to operational forecasters, LIS provides a new tool to forecasters in order to help eliminate the randomness of summertime <span class="hlt">convective</span> initiation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2000PhDT.......270C&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2000PhDT.......270C&link_type=ABSTRACT"><span id="translatedtitle">Binary porous <span class="hlt">convection</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Carey, Michael Richard</p> <p></p> <p>Binary porous <span class="hlt">convection</span> falls into the larger category of pattern formation---a symmetry breaking instability which creates a spatially periodic structure within a homogeneous system. The experiments and model presented in this dissertation indicate that an essential piece of physics is missing from the standard Darcian picture used to describe pattern formation in a porous medium <span class="hlt">convection</span> system. Present theory predicts a bifurcation to an oscillatory state at onset for a binary mixture in a porous media over a wide range of experimental parameters (Brand and Steinberg, Physics Letters 93A 333 (1983)). This theory is inadequate in explaining the predominant large amplitude, backward, stationary overturning <span class="hlt">convection</span> state observed in our experiments after transients have decayed. <span class="hlt">Convection</span> experiments were visualized with magnetic resonance imaging and performed with a foam medium in slot and cylindrical geometries as well as a rectangular, packed bead system with water-ethanol mixtures. We explore the possibility that the difference between theory and experiment is due to enhanced solutal mixing not included in previous theories. The enhanced mixing of the fluid produces an effective diffusion coefficient that largely suppresses gradients in the concentration field, resulting in single-fluid like behavior. We model the experimental system with a Lorenz truncation of the binary Darcy equations with enhanced mixing. This model predicts results qualitatively similar to experiments: a forward bifurcation to small amplitude oscillations with a secondary backward bifurcation to large amplitude stationary <span class="hlt">convection</span>. We have also developed an experimental nuclear magnetic resonance technique that measures the effective diffusion coefficient, D = D(v), as a function of velocity, v, for the individual species of the binary mixture simultaneously. However, the mixing effect measured in plug flow experiments is roughly two to three orders of magnitude too small to have</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li class="active"><span>22</span></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_22 --> <div id="page_23" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li class="active"><span>23</span></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="441"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70024674','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70024674"><span id="translatedtitle">ENSO and winter <span class="hlt">storms</span> in California</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Cayan, D.R.; Bromirski, Peter</p> <p>2003-01-01</p> <p>The frequency and intensity of North Pacific winter <span class="hlt">storms</span> that penetrate the California coast drives the winds, sea level, precipitation and streamflow that are crucial influences on coastal processes. There is considerable variability of these <span class="hlt">storm</span> characteristics, in large part owing to the El Nino/Southern Oscillation (ENSO} phenomenon. There is a great contrast of the <span class="hlt">storm</span> characteristics during the El Nino phase vs. the La Nina phase, with the largest scale, southerly extensive winter <span class="hlt">storms</span> generated during El Nino.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/6711783','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/6711783"><span id="translatedtitle">Thyroid <span class="hlt">storm</span> during beta blockade.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Strube, P J</p> <p>1984-04-01</p> <p>A thyrotoxic patient who had received beta-adrenoceptor blockers pre-operatively suffered an episode of severe heart failure immediately following thyroidectomy and required artificial ventilation of the lungs for six hours. The possible causes are discussed and the likelihood of thyroid <span class="hlt">storm</span> unmitigated by beta adrenergic blockade suggested.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryId=329630&keyword=HTML&actType=&TIMSType=+&TIMSSubTypeID=&DEID=&epaNumber=&ntisID=&archiveStatus=Both&ombCat=Any&dateBeginCreated=&dateEndCreated=&dateBeginPublishedPresented=&dateEndPublishedPresented=&dateBeginUpdated=&dateEndUpdated=&dateBeginCompleted=&dateEndCompleted=&personID=&role=Any&journalID=&publisherID=&sortBy=revisionDate&count=50&CFID=68455218&CFTOKEN=33223705','EPA-EIMS'); return false;" href="http://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryId=329630&keyword=HTML&actType=&TIMSType=+&TIMSSubTypeID=&DEID=&epaNumber=&ntisID=&archiveStatus=Both&ombCat=Any&dateBeginCreated=&dateEndCreated=&dateBeginPublishedPresented=&dateEndPublishedPresented=&dateBeginUpdated=&dateEndUpdated=&dateBeginCompleted=&dateEndCompleted=&personID=&role=Any&journalID=&publisherID=&sortBy=revisionDate&count=50&CFID=68455218&CFTOKEN=33223705"><span id="translatedtitle"><span class="hlt">Storm</span> Water Management Model (SWMM)</span></a></p> <p><a target="_blank" href="http://oaspub.epa.gov/eims/query.page">EPA Science Inventory</a></p> <p></p> <p></p> <p>Stormwater discharges continue to cause impairment of our Nation’s waterbodies. Regulations that require the retention and/or treatment of frequent, small <span class="hlt">storms</span> that dominate runoff volumes and pollutant loads are becoming more common. The U.S. Environmental Protection Agency (E...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=10546&hterms=rain&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Drain','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=10546&hterms=rain&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Drain"><span id="translatedtitle">Rain from Tropical <span class="hlt">Storm</span> Noel</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p></p> <p>2007-01-01</p> <p>Though not the most powerful <span class="hlt">storm</span> of the 2007 Atlantic Hurricane season, Tropical <span class="hlt">Storm</span> Noel was among the most deadly. Only Category 5 Hurricane Felix and its associated flooding had a higher toll. The slow-moving Tropical <span class="hlt">Storm</span> Noel inundated the Dominican Republic, Haiti, Jamaica, Cuba, and the Bahamas with heavy rain between October 28 and November 1, 2007. The resulting floods and mudslides left at least 115 dead and thousands homeless throughout the Caribbean, reported the Associated Press on November 2, 2007. This image shows the distribution of the rainfall that made Noel a deadly <span class="hlt">storm</span>. The image shows rainfall totals as measured by the Multi-satellite Precipitation Analysis (MPA) at NASA Goddard Space Flight Center from October 26 through November 1, 2007. The analysis is based on measurements taken by the Tropical Rainfall Measuring Mission (TRMM) satellite. The heaviest rainfall fell in the Dominican Republic and the Bahamas, northeast of Noel's center. Areas of dark red show that rainfall totals over the south-central Dominican Republic and parts of the Bahamas were over 551 millimeters (21 inches). Much of eastern Hispaniola, including both the Dominican Republic and Haiti received at least 200 mm (about 8 inches) of rain, shown in yellow. Rainfall totals over Haiti and Cuba were less, with a range of at least 50 mm (2 inches) to over 200 mm (8 inches).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryId=329630&keyword=f&actType=&TIMSType=+&TIMSSubTypeID=&DEID=&epaNumber=&ntisID=&archiveStatus=Both&ombCat=Any&dateBeginCreated=&dateEndCreated=&dateBeginPublishedPresented=&dateEndPublishedPresented=&dateBeginUpdated=&dateEndUpdated=&dateBeginCompleted=&dateEndCompleted=&personID=&role=Any&journalID=&publisherID=&sortBy=revisionDate&count=50&CFID=78920981&CFTOKEN=35724075','EPA-EIMS'); return false;" href="http://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryId=329630&keyword=f&actType=&TIMSType=+&TIMSSubTypeID=&DEID=&epaNumber=&ntisID=&archiveStatus=Both&ombCat=Any&dateBeginCreated=&dateEndCreated=&dateBeginPublishedPresented=&dateEndPublishedPresented=&dateBeginUpdated=&dateEndUpdated=&dateBeginCompleted=&dateEndCompleted=&personID=&role=Any&journalID=&publisherID=&sortBy=revisionDate&count=50&CFID=78920981&CFTOKEN=35724075"><span id="translatedtitle"><span class="hlt">Storm</span> Water Management Model (SWMM)</span></a></p> <p><a target="_blank" href="http://oaspub.epa.gov/eims/query.page">EPA Science Inventory</a></p> <p></p> <p></p> <p>Stormwater discharges continue to cause impairment of our Nation’s waterbodies. Regulations that require the retention and/or treatment of frequent, small <span class="hlt">storms</span> that dominate runoff volumes and pollutant loads are becoming more common. The U.S. Environmental Protection Age...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AGUFM.A42C..02M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AGUFM.A42C..02M"><span id="translatedtitle">Insights into mid-latitude <span class="hlt">storm</span> track dynamics from simulations with an idealized dry GCM</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Mbengue, C. O.; Schneider, T.</p> <p>2012-12-01</p> <p>The mid-latitude <span class="hlt">storm</span> tracks play an important role in balancing the earth's heat and momentum budget. They have a significant human impact through precipitation and adverse weather conditions; thus, the <span class="hlt">storm</span> track response to changing climatic conditions is of great interest. In this study, we investigate the climatological response of the mid-latitude <span class="hlt">storm</span> tracks to varying mean global temperature and <span class="hlt">convective</span> static stability, using an idealized dry GCM. We demonstrate <span class="hlt">storm</span> track migration in response to changes in global-mean surface temperatures without modifying the surface pole-equator temperature contrast or including moisture-related effects. The results help interpret the findings of previous global warming studies in which the mid-latitude <span class="hlt">storm</span> tracks migrate poleward with increasing mean global temperatures. In our study, the <span class="hlt">storm</span> track position is found to be particularly sensitive to changes in tropical static stability and tropopause height and their effect on the Hadley circulation. The mechanisms driving the dynamics of the mid-latitude <span class="hlt">storm</span> tracks have been elusive. However, making use of the simplified framework employed in this study, which lends itself to dynamical decompositions, we have been able to improve upon some existing theories on <span class="hlt">storm</span> track dynamics in dry atmospheres, as well as make additional observations. Previous studies into dry atmospheric dynamics have shown a linear scaling between eddy kinetic energy, a robust measure of the level of storminess, and the mean available potential energy (MAPE). This scaling is utilized in a decomposition that shows that the dominant quantity in <span class="hlt">storm</span> track dynamics is the meridional gradient of the potential temperature—a measure of baroclinicity. This observation leads us to look for dynamical mechanisms that, on average, dictate the location of regions of elevated baroclinicity. Some credible explanations include the effects on mid-latitude isentropic slopes through a raising or</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20110008300','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20110008300"><span id="translatedtitle">Predicting Airspace Capacity Impacts Using the Consolidated <span class="hlt">Storm</span> Prediction for Aviation</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Russell, Carl</p> <p>2010-01-01</p> <p><span class="hlt">Convective</span> weather is currently the largest contributor to air traffic delays in the United States. In order to make effective traffic flow management decisions to mitigate these delays, weather forecasts must be made as early and as accurately as possible. A forecast product that could be used to mitigate <span class="hlt">convective</span> weather impacts is the Consolidated <span class="hlt">Storm</span> Prediction for Aviation. This product provides forecasts of cloud water content and <span class="hlt">convective</span> top heights at 0- to 8-hour look-ahead times. The objective of this study was to examine a method of predicting the impact of <span class="hlt">convective</span> weather on air traffic sector capacities using these forecasts. Polygons representing forecast <span class="hlt">convective</span> weather were overlaid at multiple flight levels on a sector map to calculate the fraction of each sector covered by weather. The fractional volume coverage was used as the primary metric to determine <span class="hlt">convection</span> s impact on sectors. Results reveal that the forecasts can be used to predict the probability and magnitude of weather impacts on sector capacity up to eight hours in advance.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/15009797','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/15009797"><span id="translatedtitle">Asian <span class="hlt">Summer</span> Monsoon Intraseasonal Variability in General Circulation Models</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Sperber, K R; Annamalai, H</p> <p>2004-02-24</p> <p>The goals of this report are: (1) Analyze boreal <span class="hlt">summer</span> Asian monsoon intraseasonal variability general circulation models--How well do the models represent the eastward and northward propagating components of the <span class="hlt">convection</span> and how well do the models represent the interactive control that the western tropical Pacific rainfall exerts on the rainfall over India and vice-versa? (2) Role of air-sea interactions--prescribed vs. interactive ocean; and (3) Mean monsoon vs. variability.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19820010933','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19820010933"><span id="translatedtitle">Winter and <span class="hlt">summer</span> simulations with the GLAS climate model</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Shukla, J.; Straus, D.; Randall, D.; Sud, Y.; Marx, L.</p> <p>1981-01-01</p> <p>The GLAS climate model is a general circulation model based on the primitive equations in sigma coordinates on a global domain in the presence of orography. The model incorporates parameterizations of the effects of radiation, <span class="hlt">convection</span>, large scale latent heat release, turbulent and boundary layer fluxes, and ground hydrology. Winter and <span class="hlt">summer</span> simulations were carried out with this model, and the resulting data are compared to observations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ars.usda.gov/research/publications/publication/?seqNo115=220341','TEKTRAN'); return false;" href="http://www.ars.usda.gov/research/publications/publication/?seqNo115=220341"><span id="translatedtitle">Characterizing Times Between <span class="hlt">Storms</span> in Mountainous Areas</span></a></p> <p><a target="_blank" href="http://www.ars.usda.gov/services/TekTran.htm">Technology Transfer Automated Retrieval System (TEKTRAN)</a></p> <p></p> <p></p> <p>An exploratory investigation was conducted on how two parameters that characterize dry times between <span class="hlt">storms</span> (average time between <span class="hlt">storms</span>, ATBS, and minimum dry time between <span class="hlt">storms</span>, MTBS) vary with elevation, and how these two parameters may be estimated for areas without data. 16 rain gauges with h...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2014-title46-vol7/pdf/CFR-2014-title46-vol7-sec177-920.pdf','CFR2014'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2014-title46-vol7/pdf/CFR-2014-title46-vol7-sec177-920.pdf"><span id="translatedtitle">46 CFR 177.920 - <span class="hlt">Storm</span> rails.</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2014&page.go=Go">Code of Federal Regulations, 2014 CFR</a></p> <p></p> <p>2014-10-01</p> <p>... 46 Shipping 7 2014-10-01 2014-10-01 false <span class="hlt">Storm</span> rails. 177.920 Section 177.920 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) SMALL PASSENGER VESSELS (UNDER 100 GROSS TONS) CONSTRUCTION AND ARRANGEMENT Rails and Guards § 177.920 <span class="hlt">Storm</span> rails. Suitable <span class="hlt">storm</span> rails or hand grabs must...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2014-title46-vol4/pdf/CFR-2014-title46-vol4-sec116-920.pdf','CFR2014'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2014-title46-vol4/pdf/CFR-2014-title46-vol4-sec116-920.pdf"><span id="translatedtitle">46 CFR 116.920 - <span class="hlt">Storm</span> rails.</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2014&page.go=Go">Code of Federal Regulations, 2014 CFR</a></p> <p></p> <p>2014-10-01</p> <p>... 46 Shipping 4 2014-10-01 2014-10-01 false <span class="hlt">Storm</span> rails. 116.920 Section 116.920 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) SMALL PASSENGER VESSELS CARRYING MORE THAN 150... and Guards § 116.920 <span class="hlt">Storm</span> rails. Suitable <span class="hlt">storm</span> rails or hand grabs must be installed where...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2013-title46-vol4/pdf/CFR-2013-title46-vol4-sec116-920.pdf','CFR2013'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2013-title46-vol4/pdf/CFR-2013-title46-vol4-sec116-920.pdf"><span id="translatedtitle">46 CFR 116.920 - <span class="hlt">Storm</span> rails.</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2013&page.go=Go">Code of Federal Regulations, 2013 CFR</a></p> <p></p> <p>2013-10-01</p> <p>... 46 Shipping 4 2013-10-01 2013-10-01 false <span class="hlt">Storm</span> rails. 116.920 Section 116.920 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) SMALL PASSENGER VESSELS CARRYING MORE THAN 150... and Guards § 116.920 <span class="hlt">Storm</span> rails. Suitable <span class="hlt">storm</span> rails or hand grabs must be installed where...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2010-title46-vol7/pdf/CFR-2010-title46-vol7-sec169-329.pdf','CFR'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2010-title46-vol7/pdf/CFR-2010-title46-vol7-sec169-329.pdf"><span id="translatedtitle">46 CFR 169.329 - <span class="hlt">Storm</span> rails.</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2010&page.go=Go">Code of Federal Regulations, 2010 CFR</a></p> <p></p> <p>2010-10-01</p> <p>... 46 Shipping 7 2010-10-01 2010-10-01 false <span class="hlt">Storm</span> rails. 169.329 Section 169.329 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) NAUTICAL SCHOOLS SAILING SCHOOL VESSELS Construction and Arrangement Rails and Guards § 169.329 <span class="hlt">Storm</span> rails. Suitable <span class="hlt">storm</span> rails or hand grabs must...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2014-title46-vol7/pdf/CFR-2014-title46-vol7-sec169-329.pdf','CFR2014'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2014-title46-vol7/pdf/CFR-2014-title46-vol7-sec169-329.pdf"><span id="translatedtitle">46 CFR 169.329 - <span class="hlt">Storm</span> rails.</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2014&page.go=Go">Code of Federal Regulations, 2014 CFR</a></p> <p></p> <p>2014-10-01</p> <p>... 46 Shipping 7 2014-10-01 2014-10-01 false <span class="hlt">Storm</span> rails. 169.329 Section 169.329 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) NAUTICAL SCHOOLS SAILING SCHOOL VESSELS Construction and Arrangement Rails and Guards § 169.329 <span class="hlt">Storm</span> rails. Suitable <span class="hlt">storm</span> rails or hand grabs must...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2011-title46-vol4/pdf/CFR-2011-title46-vol4-sec127-320.pdf','CFR2011'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2011-title46-vol4/pdf/CFR-2011-title46-vol4-sec127-320.pdf"><span id="translatedtitle">46 CFR 127.320 - <span class="hlt">Storm</span> rails.</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2011&page.go=Go">Code of Federal Regulations, 2011 CFR</a></p> <p></p> <p>2011-10-01</p> <p>... 46 Shipping 4 2011-10-01 2011-10-01 false <span class="hlt">Storm</span> rails. 127.320 Section 127.320 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) OFFSHORE SUPPLY VESSELS CONSTRUCTION AND ARRANGEMENTS Rails and Guards § 127.320 <span class="hlt">Storm</span> rails. Suitable <span class="hlt">storm</span> rails must be installed in each passageway and...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2012-title46-vol7/pdf/CFR-2012-title46-vol7-sec177-920.pdf','CFR2012'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2012-title46-vol7/pdf/CFR-2012-title46-vol7-sec177-920.pdf"><span id="translatedtitle">46 CFR 177.920 - <span class="hlt">Storm</span> rails.</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2012&page.go=Go">Code of Federal Regulations, 2012 CFR</a></p> <p></p> <p>2012-10-01</p> <p>... 46 Shipping 7 2012-10-01 2012-10-01 false <span class="hlt">Storm</span> rails. 177.920 Section 177.920 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) SMALL PASSENGER VESSELS (UNDER 100 GROSS TONS) CONSTRUCTION AND ARRANGEMENT Rails and Guards § 177.920 <span class="hlt">Storm</span> rails. Suitable <span class="hlt">storm</span> rails or hand grabs must...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2012-title46-vol7/pdf/CFR-2012-title46-vol7-sec169-329.pdf','CFR2012'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2012-title46-vol7/pdf/CFR-2012-title46-vol7-sec169-329.pdf"><span id="translatedtitle">46 CFR 169.329 - <span class="hlt">Storm</span> rails.</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2012&page.go=Go">Code of Federal Regulations, 2012 CFR</a></p> <p></p> <p>2012-10-01</p> <p>... 46 Shipping 7 2012-10-01 2012-10-01 false <span class="hlt">Storm</span> rails. 169.329 Section 169.329 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) NAUTICAL SCHOOLS SAILING SCHOOL VESSELS Construction and Arrangement Rails and Guards § 169.329 <span class="hlt">Storm</span> rails. Suitable <span class="hlt">storm</span> rails or hand grabs must...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2012-title46-vol4/pdf/CFR-2012-title46-vol4-sec116-920.pdf','CFR2012'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2012-title46-vol4/pdf/CFR-2012-title46-vol4-sec116-920.pdf"><span id="translatedtitle">46 CFR 116.920 - <span class="hlt">Storm</span> rails.</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2012&page.go=Go">Code of Federal Regulations, 2012 CFR</a></p> <p></p> <p>2012-10-01</p> <p>... 46 Shipping 4 2012-10-01 2012-10-01 false <span class="hlt">Storm</span> rails. 116.920 Section 116.920 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) SMALL PASSENGER VESSELS CARRYING MORE THAN 150... and Guards § 116.920 <span class="hlt">Storm</span> rails. Suitable <span class="hlt">storm</span> rails or hand grabs must be installed where...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2013-title46-vol4/pdf/CFR-2013-title46-vol4-sec127-320.pdf','CFR2013'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2013-title46-vol4/pdf/CFR-2013-title46-vol4-sec127-320.pdf"><span id="translatedtitle">46 CFR 127.320 - <span class="hlt">Storm</span> rails.</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2013&page.go=Go">Code of Federal Regulations, 2013 CFR</a></p> <p></p> <p>2013-10-01</p> <p>... 46 Shipping 4 2013-10-01 2013-10-01 false <span class="hlt">Storm</span> rails. 127.320 Section 127.320 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) OFFSHORE SUPPLY VESSELS CONSTRUCTION AND ARRANGEMENTS Rails and Guards § 127.320 <span class="hlt">Storm</span> rails. Suitable <span class="hlt">storm</span> rails must be installed in each passageway and...</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li class="active"><span>23</span></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_23 --> <div id="page_24" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li class="active"><span>24</span></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="461"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2014-title46-vol4/pdf/CFR-2014-title46-vol4-sec127-320.pdf','CFR2014'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2014-title46-vol4/pdf/CFR-2014-title46-vol4-sec127-320.pdf"><span id="translatedtitle">46 CFR 127.320 - <span class="hlt">Storm</span> rails.</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2014&page.go=Go">Code of Federal Regulations, 2014 CFR</a></p> <p></p> <p>2014-10-01</p> <p>... 46 Shipping 4 2014-10-01 2014-10-01 false <span class="hlt">Storm</span> rails. 127.320 Section 127.320 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) OFFSHORE SUPPLY VESSELS CONSTRUCTION AND ARRANGEMENTS Rails and Guards § 127.320 <span class="hlt">Storm</span> rails. Suitable <span class="hlt">storm</span> rails must be installed in each passageway and...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2013-title46-vol4/pdf/CFR-2013-title46-vol4-sec108-221.pdf','CFR2013'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2013-title46-vol4/pdf/CFR-2013-title46-vol4-sec108-221.pdf"><span id="translatedtitle">46 CFR 108.221 - <span class="hlt">Storm</span> rails.</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2013&page.go=Go">Code of Federal Regulations, 2013 CFR</a></p> <p></p> <p>2013-10-01</p> <p>... 46 Shipping 4 2013-10-01 2013-10-01 false <span class="hlt">Storm</span> rails. 108.221 Section 108.221 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) A-MOBILE OFFSHORE DRILLING UNITS DESIGN AND EQUIPMENT Construction and Arrangement Rails § 108.221 <span class="hlt">Storm</span> rails. Each unit must have a <span class="hlt">storm</span> rail in the...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2011-title46-vol4/pdf/CFR-2011-title46-vol4-sec108-221.pdf','CFR2011'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2011-title46-vol4/pdf/CFR-2011-title46-vol4-sec108-221.pdf"><span id="translatedtitle">46 CFR 108.221 - <span class="hlt">Storm</span> rails.</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2011&page.go=Go">Code of Federal Regulations, 2011 CFR</a></p> <p></p> <p>2011-10-01</p> <p>... 46 Shipping 4 2011-10-01 2011-10-01 false <span class="hlt">Storm</span> rails. 108.221 Section 108.221 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) A-MOBILE OFFSHORE DRILLING UNITS DESIGN AND EQUIPMENT Construction and Arrangement Rails § 108.221 <span class="hlt">Storm</span> rails. Each unit must have a <span class="hlt">storm</span> rail in the...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2013-title46-vol7/pdf/CFR-2013-title46-vol7-sec177-920.pdf','CFR2013'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2013-title46-vol7/pdf/CFR-2013-title46-vol7-sec177-920.pdf"><span id="translatedtitle">46 CFR 177.920 - <span class="hlt">Storm</span> rails.</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2013&page.go=Go">Code of Federal Regulations, 2013 CFR</a></p> <p></p> <p>2013-10-01</p> <p>... 46 Shipping 7 2013-10-01 2013-10-01 false <span class="hlt">Storm</span> rails. 177.920 Section 177.920 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) SMALL PASSENGER VESSELS (UNDER 100 GROSS TONS) CONSTRUCTION AND ARRANGEMENT Rails and Guards § 177.920 <span class="hlt">Storm</span> rails. Suitable <span class="hlt">storm</span> rails or hand grabs must...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2011-title46-vol4/pdf/CFR-2011-title46-vol4-sec116-920.pdf','CFR2011'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2011-title46-vol4/pdf/CFR-2011-title46-vol4-sec116-920.pdf"><span id="translatedtitle">46 CFR 116.920 - <span class="hlt">Storm</span> rails.</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2011&page.go=Go">Code of Federal Regulations, 2011 CFR</a></p> <p></p> <p>2011-10-01</p> <p>... 46 Shipping 4 2011-10-01 2011-10-01 false <span class="hlt">Storm</span> rails. 116.920 Section 116.920 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) SMALL PASSENGER VESSELS CARRYING MORE THAN 150... and Guards § 116.920 <span class="hlt">Storm</span> rails. Suitable <span class="hlt">storm</span> rails or hand grabs must be installed where...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2011-title46-vol7/pdf/CFR-2011-title46-vol7-sec177-920.pdf','CFR2011'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2011-title46-vol7/pdf/CFR-2011-title46-vol7-sec177-920.pdf"><span id="translatedtitle">46 CFR 177.920 - <span class="hlt">Storm</span> rails.</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2011&page.go=Go">Code of Federal Regulations, 2011 CFR</a></p> <p></p> <p>2011-10-01</p> <p>... 46 Shipping 7 2011-10-01 2011-10-01 false <span class="hlt">Storm</span> rails. 177.920 Section 177.920 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) SMALL PASSENGER VESSELS (UNDER 100 GROSS TONS) CONSTRUCTION AND ARRANGEMENT Rails and Guards § 177.920 <span class="hlt">Storm</span> rails. Suitable <span class="hlt">storm</span> rails or hand grabs must...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2010-title46-vol4/pdf/CFR-2010-title46-vol4-sec127-320.pdf','CFR'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2010-title46-vol4/pdf/CFR-2010-title46-vol4-sec127-320.pdf"><span id="translatedtitle">46 CFR 127.320 - <span class="hlt">Storm</span> rails.</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2010&page.go=Go">Code of Federal Regulations, 2010 CFR</a></p> <p></p> <p>2010-10-01</p> <p>... 46 Shipping 4 2010-10-01 2010-10-01 false <span class="hlt">Storm</span> rails. 127.320 Section 127.320 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) OFFSHORE SUPPLY VESSELS CONSTRUCTION AND ARRANGEMENTS Rails and Guards § 127.320 <span class="hlt">Storm</span> rails. Suitable <span class="hlt">storm</span> rails must be installed in each passageway and...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2010-title46-vol4/pdf/CFR-2010-title46-vol4-sec108-221.pdf','CFR'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2010-title46-vol4/pdf/CFR-2010-title46-vol4-sec108-221.pdf"><span id="translatedtitle">46 CFR 108.221 - <span class="hlt">Storm</span> rails.</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2010&page.go=Go">Code of Federal Regulations, 2010 CFR</a></p> <p></p> <p>2010-10-01</p> <p>... 46 Shipping 4 2010-10-01 2010-10-01 false <span class="hlt">Storm</span> rails. 108.221 Section 108.221 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) A-MOBILE OFFSHORE DRILLING UNITS DESIGN AND EQUIPMENT Construction and Arrangement Rails § 108.221 <span class="hlt">Storm</span> rails. Each unit must have a <span class="hlt">storm</span> rail in the...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2010-title46-vol4/pdf/CFR-2010-title46-vol4-sec116-920.pdf','CFR'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2010-title46-vol4/pdf/CFR-2010-title46-vol4-sec116-920.pdf"><span id="translatedtitle">46 CFR 116.920 - <span class="hlt">Storm</span> rails.</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2010&page.go=Go">Code of Federal Regulations, 2010 CFR</a></p> <p></p> <p>2010-10-01</p> <p>... 46 Shipping 4 2010-10-01 2010-10-01 false <span class="hlt">Storm</span> rails. 116.920 Section 116.920 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) SMALL PASSENGER VESSELS CARRYING MORE THAN 150... and Guards § 116.920 <span class="hlt">Storm</span> rails. Suitable <span class="hlt">storm</span> rails or hand grabs must be installed where...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2012-title46-vol4/pdf/CFR-2012-title46-vol4-sec127-320.pdf','CFR2012'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2012-title46-vol4/pdf/CFR-2012-title46-vol4-sec127-320.pdf"><span id="translatedtitle">46 CFR 127.320 - <span class="hlt">Storm</span> rails.</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2012&page.go=Go">Code of Federal Regulations, 2012 CFR</a></p> <p></p> <p>2012-10-01</p> <p>... 46 Shipping 4 2012-10-01 2012-10-01 false <span class="hlt">Storm</span> rails. 127.320 Section 127.320 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) OFFSHORE SUPPLY VESSELS CONSTRUCTION AND ARRANGEMENTS Rails and Guards § 127.320 <span class="hlt">Storm</span> rails. Suitable <span class="hlt">storm</span> rails must be installed in each passageway and...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2010-title46-vol7/pdf/CFR-2010-title46-vol7-sec177-920.pdf','CFR'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2010-title46-vol7/pdf/CFR-2010-title46-vol7-sec177-920.pdf"><span id="translatedtitle">46 CFR 177.920 - <span class="hlt">Storm</span> rails.</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2010&page.go=Go">Code of Federal Regulations, 2010 CFR</a></p> <p></p> <p>2010-10-01</p> <p>... 46 Shipping 7 2010-10-01 2010-10-01 false <span class="hlt">Storm</span> rails. 177.920 Section 177.920 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) SMALL PASSENGER VESSELS (UNDER 100 GROSS TONS) CONSTRUCTION AND ARRANGEMENT Rails and Guards § 177.920 <span class="hlt">Storm</span> rails. Suitable <span class="hlt">storm</span> rails or hand grabs must...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2013-title46-vol7/pdf/CFR-2013-title46-vol7-sec169-329.pdf','CFR2013'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2013-title46-vol7/pdf/CFR-2013-title46-vol7-sec169-329.pdf"><span id="translatedtitle">46 CFR 169.329 - <span class="hlt">Storm</span> rails.</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2013&page.go=Go">Code of Federal Regulations, 2013 CFR</a></p> <p></p> <p>2013-10-01</p> <p>... 46 Shipping 7 2013-10-01 2013-10-01 false <span class="hlt">Storm</span> rails. 169.329 Section 169.329 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) NAUTICAL SCHOOLS SAILING SCHOOL VESSELS Construction and Arrangement Rails and Guards § 169.329 <span class="hlt">Storm</span> rails. Suitable <span class="hlt">storm</span> rails or hand grabs must...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2014-title46-vol4/pdf/CFR-2014-title46-vol4-sec108-221.pdf','CFR2014'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2014-title46-vol4/pdf/CFR-2014-title46-vol4-sec108-221.pdf"><span id="translatedtitle">46 CFR 108.221 - <span class="hlt">Storm</span> rails.</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2014&page.go=Go">Code of Federal Regulations, 2014 CFR</a></p> <p></p> <p>2014-10-01</p> <p>... 46 Shipping 4 2014-10-01 2014-10-01 false <span class="hlt">Storm</span> rails. 108.221 Section 108.221 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) A-MOBILE OFFSHORE DRILLING UNITS DESIGN AND EQUIPMENT Construction and Arrangement Rails § 108.221 <span class="hlt">Storm</span> rails. Each unit must have a <span class="hlt">storm</span> rail in the...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2011-title46-vol7/pdf/CFR-2011-title46-vol7-sec169-329.pdf','CFR2011'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2011-title46-vol7/pdf/CFR-2011-title46-vol7-sec169-329.pdf"><span id="translatedtitle">46 CFR 169.329 - <span class="hlt">Storm</span> rails.</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2011&page.go=Go">Code of Federal Regulations, 2011 CFR</a></p> <p></p> <p>2011-10-01</p> <p>... 46 Shipping 7 2011-10-01 2011-10-01 false <span class="hlt">Storm</span> rails. 169.329 Section 169.329 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) NAUTICAL SCHOOLS SAILING SCHOOL VESSELS Construction and Arrangement Rails and Guards § 169.329 <span class="hlt">Storm</span> rails. Suitable <span class="hlt">storm</span> rails or hand grabs must...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2012-title46-vol4/pdf/CFR-2012-title46-vol4-sec108-221.pdf','CFR2012'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2012-title46-vol4/pdf/CFR-2012-title46-vol4-sec108-221.pdf"><span id="translatedtitle">46 CFR 108.221 - <span class="hlt">Storm</span> rails.</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2012&page.go=Go">Code of Federal Regulations, 2012 CFR</a></p> <p></p> <p>2012-10-01</p> <p>... 46 Shipping 4 2012-10-01 2012-10-01 false <span class="hlt">Storm</span> rails. 108.221 Section 108.221 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) A-MOBILE OFFSHORE DRILLING UNITS DESIGN AND EQUIPMENT Construction and Arrangement Rails § 108.221 <span class="hlt">Storm</span> rails. Each unit must have a <span class="hlt">storm</span> rail in the...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20130010141','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20130010141"><span id="translatedtitle">Alabama Ground Operations during the Deep <span class="hlt">Convective</span> Clouds and Chemistry Experiment</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Carey, Lawrence; Blakeslee, Richard; Koshak, William; Bain, Lamont; Rogers, Ryan; Kozlowski, Danielle; Sherrer, Adam; Saari, Matt; Bigelbach, Brandon; Scott, Mariana; Schultz, Elise; Schultz, Chris; Gatlin, Patrick; Wingo, Matt; Phillips, Dustin; Phillips, Chris; Peterson, Harold; Bailey, Jeff; Frederickson, Terryn; Hall, John; Bart, Nicole; Becker, Melissa; Pinkney, Kurtis; Rowe, Scott; Starzec, Mariusz</p> <p>2013-01-01</p> <p>The Deep <span class="hlt">Convective</span> Clouds and Chemistry (DC3) field campaign investigates the impact of deep, midlatitude <span class="hlt">convective</span> clouds, including their dynamical, physical and lighting processes, on upper tropospheric composition and chemistry. DC3 science operations took place from 14 May to 30 June 2012. The DC3 field campaign utilized instrumented aircraft and ground ]based observations. The NCAR Gulfstream ]V (GV) observed a variety of gas ]phase species, radiation and cloud particle characteristics in the high ]altitude outflow of <span class="hlt">storms</span> while the NASA DC ]8 characterized the <span class="hlt">convective</span> inflow. Groundbased radar networks were used to document the kinematic and microphysical characteristics of <span class="hlt">storms</span>. In order to study the impact of lightning on <span class="hlt">convective</span> outflow composition, VHF ]based lightning mapping arrays (LMAs) provided detailed three ]dimensional measurements of flashes. Mobile soundings were utilized to characterize the meteorological environment of the <span class="hlt">convection</span>. Radar, sounding and lightning observations were also used in real ]time to provide forecasting and mission guidance to the aircraft operations. Combined aircraft and ground ]based observations were conducted at three locations, 1) northeastern Colorado, 2) Oklahoma/Texas and 3) northern Alabama, to study different modes of deep <span class="hlt">convection</span> in a variety of meteorological and chemical environments. The objective of this paper is to summarize the Alabama ground operations and provide a preliminary assessment of the ground ]based observations collected over northern Alabama during DC3. The multi ] Doppler, dual ]polarization radar network consisted of the UAHuntsville Advanced Radar for Meteorological and Operational Research (ARMOR), the UAHuntsville Mobile Alabama X ]band (MAX) radar and the Hytop (KHTX) Weather Surveillance Radar 88 Doppler (WSR ]88D). Lightning frequency and structure were observed in near real ]time by the NASA MSFC Northern Alabama LMA (NALMA). Pre ]<span class="hlt">storm</span> and inflow proximity</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFM.A12C..08F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFM.A12C..08F"><span id="translatedtitle">Observations Suggestive of Ice Production through Secondary Processes in <span class="hlt">Convective</span> Clouds in Southwest England</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>French, J.; Leon, D.; Jackson, R.; Plummer, D. M.; Sulskis, J. A.; Lasher-Trapp, S.; Blyth, A. M.</p> <p>2015-12-01</p> <p>Although the UK is well known for persistent drizzle, summertime in the UK is often accompanied by heavy <span class="hlt">convective</span> precipitation. Summertime <span class="hlt">convective</span> <span class="hlt">storms</span> over the southwestern peninsula of the UK were the subject of the <span class="hlt">COnvective</span> Precipitation Experiment (COPE), conducted in July and August of 2013. With an aim to improving quantitative precipitation forecasts, one of the primary objectives of COPE was to document the microphysical evolution of <span class="hlt">convective</span> <span class="hlt">storms</span> and unravel the contributions of the many microphysical pathways that can lead to heavy <span class="hlt">convective</span> rainfall. <span class="hlt">Convective</span> <span class="hlt">storms</span> over southwest England are somewhat unusual, with low but cool cloud bases that can still provide ample time for development of precipitation through warm processes. The production of precipitation between cloud base through (and somewhat above) the 0 °C level plays an important role in the further microphysical evolution of the cloud as ascent continues. In some cases, we observed a rapid transition from cloud liquid to ice, presumably amplified through secondary ice production. In others, we found very little production of ice at similar temperature levels. Here we investigate details of the microphysics and dynamics from select cases on four days from COPE using in situ observations from an instrumented aircraft and high-resolution measurements from an airborne radar. In particular, we investigate how frozen raindrops in the Hallet-Mossop zone (-3 to -8 °C) influences the production of small ice crystals. We further investigate the expected time these frozen drops, or graupel embryos, persist in the H-M zone to understand the role updraft speed plays in secondary ice production leading to rapid glaciation of the cloud.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFM.A23K3392H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFM.A23K3392H"><span id="translatedtitle">Numerical Simulations of Upper Troposphere/Lower Stratosphere (UTLS) Structure and Cross-Tropopause Transport in Deep Extratropical <span class="hlt">Convection</span>: Sensitivities to Grid Resolution</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Homeyer, C. R.</p> <p>2014-12-01</p> <p>Deep extratropical <span class="hlt">convection</span> that overshoots the altitude of the tropopause is a process that has important implications both for chemistry-climate interactions through stratosphere-troposphere exchange and for hazardous weather at the Earth's surface. Notably, <span class="hlt">convective</span> injection of copious amounts of water vapor into the lower stratosphere has direct and significant impacts on the radiation budget and consequently, climate. In this study, the sensitivity of cross-tropopause transport and UTLS structure in extratropical <span class="hlt">convection</span> to the choice of numerical model resolution in simulations of explicitly-resolved <span class="hlt">convection</span> (i.e., no <span class="hlt">convective</span> parameterization) is examined. For an observed case of overshooting <span class="hlt">convection</span>, the Advanced Research Weather Research and Forecasting (ARW-WRF) model is run for all possible combinations of three horizontal (3-km,1-km,333-m) and vertical (600-m,300-m,150-m) resolutions. Although the model is successful in simulating overshooting <span class="hlt">convection</span> and cross-tropopause transport in each case, the depth and magnitude of troposphere-to-stratosphere transport is found to decrease with refinement in the vertical dimension and increase with refinement in the horizontal dimension. In addition, modifications to the altitude of the tropopause and the simulated depth of the <span class="hlt">convective</span> <span class="hlt">storms</span> show important sensitivities. Notably, the accuracy in the depth of the simulated <span class="hlt">storm</span> is primarily dependent on vertical resolution. Recommendations for future modeling studies of extratropical <span class="hlt">convection</span> and cross-tropopause transport will be given.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70013400','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70013400"><span id="translatedtitle">RECOVERY OF MONTEREY BAY BEACHES AFTER THE WINTER <span class="hlt">STORMS</span> OF 1982-83.</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Dingler, John R.; Anima, Roberto J.; Clifton, H. Edward</p> <p>1985-01-01</p> <p>The El Nino conditions of 1982 and 1983 produced unusually frequent and intense <span class="hlt">storms</span> along the central California coast. These <span class="hlt">storms</span> produced much greater than normal beach erosion in Monterey Bay, causing extensive damage to coastal structures, erosion of coastal cliffs, and loss of sand from coastal dunes. The beaches accreted during the <span class="hlt">summer</span> of 1983 and eroded again the next winter. Every beach, however, showed its own pattern of rebuilding; the eigenfunction analysis showed that the beaches did not all reach either their maximum or minimum volumes at the same time.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016DPS....4851404I','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016DPS....4851404I"><span id="translatedtitle">HST/WFC3 Observations of Uranus' 2014 <span class="hlt">Storm</span> Clouds</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Irwin, Patrick Gerard Joseph; Simon, Amy A.; Wong, Michael H.; Orton, Glenn S.; Toledo, Daniel</p> <p>2016-10-01</p> <p>In November 2014 Uranus was observed with the Wide Field Camera 3 (WFC3) instrument of the Hubble Space Telescope as part of the Hubble 2020: Outer Planet Atmospheres Legacy program, OPAL. OPAL annually maps Jupiter, Uranus and Neptune (and also Saturn from 2018) in several visible/near-IR wavelength filters. The Uranus 2014 OPAL observations were made on the 8 – 9th November at a time when a huge <span class="hlt">convective</span> <span class="hlt">storm</span> system, first observed by amateur astronomers, was present at 30 – 40°N. The entire visible atmosphere, including the <span class="hlt">storm</span> system, was imaged in seven filters spanning 467 – 924 nm, capturing variations in the coloration of Uranus' clouds and also vertical distribution due to wavelength dependent changes in Rayleigh scattering and methane absorption. Here we analyse these new HST observations with the NEMESIS radiative-transfer and retrieval code, in multiple-scattering mode, to determine the vertical cloud structure in and around the <span class="hlt">convective</span> <span class="hlt">storm</span> cloud system.The same <span class="hlt">storm</span> system was also observed in the H-band (1.4 – 1.9 µm) with the SINFONI Integral Field Unit Spectrometer on the Very Large Telescope (VLT) on 31st October and 11th November (Irwin et al., 2016, 10.1016/j.icarus.2015.09.010). To constrain better the cloud particle sizes and scattering properties over a wide wavelength range we also conducted a limb-darkening analysis of the background cloud structure in the 30 – 40°N latitude band by simultaneously fitting: a) these HST/OPAL observations at a range of zenith angles; b) the VLT/SINFONI observations at a range of zenith angles; and c) IRTF/SpeX observations of this latitude band made in 2009 at a single zenith angle of 23°, spanning the wavelength range 0.8 – 1.8 µm (Irwin et al., 2015, 10.1016/j.icarus.2014.12.020).We find that the HST observations and the combined HST/VLT/IRTF observations are well modeled with a three-component cloud comprised of: 1) a thin 'deep' cloud at a pressure of ~2 bars; 2) a methane</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li class="active"><span>24</span></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_24 --> <div id="page_25" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li class="active"><span>25</span></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="481"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009AGUFM.A13I0367J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009AGUFM.A13I0367J"><span id="translatedtitle">Estimation of <span class="hlt">Convective</span> Momentum Fluxes Using Satellite-Based Methods</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Jewett, C.; Mecikalski, J. R.</p> <p>2009-12-01</p> <p>Research and case studies have shown that <span class="hlt">convection</span> plays a significant role in large-scale environmental circulations. <span class="hlt">Convective</span> momentum fluxes (CMFs) have been studied for many years using in-situ and aircraft measurements, along with numerical simulations. However, despite these successes, little work has been conducted on methods that use satellite remote sensing as a tool to diagnose these fluxes. Uses of satellite data have the capability to provide continuous analysis across regions void of ground-based remote sensing. Therefore, the project's overall goal is to develop a synergistic approach for retrieving CMFs using a collection of instruments including GOES, TRMM, CloudSat, MODIS, and QuikScat. However, this particular study will focus on the work using TRMM and QuikScat, and the methodology of using CloudSat. Sound research has already been conducted for computing CMFs using the GOES instruments (Jewett and Mecikalski 2009, submitted to J. Geophys. Res.). Using satellite-derived winds, namely mesoscale atmospheric motion vectors (MAMVs) as described by Bedka and Mecikalski (2005), one can obtain the actual winds occurring within a <span class="hlt">convective</span> environment as perturbed by <span class="hlt">convection</span>. Surface outflow boundaries and upper-tropospheric anvil outflow will produce “perturbation” winds on smaller, <span class="hlt">convective</span> scales. Combined with estimated vertical motion retrieved using geostationary infrared imagery, CMFs were estimated using MAMVs, with an average profile being calculated across a <span class="hlt">convective</span> regime or a domain covered by active <span class="hlt">storms</span>. This study involves estimating draft-tilt from TRMM PR radar reflectivity and sub-cloud base fluxes using QuikScat data. The “slope” of falling hydrometeors (relative to Earth) in data are related to u', v' and w' winds within <span class="hlt">convection</span>. The main up- and down-drafts within <span class="hlt">convection</span> are described by precipitation patterns (Mecikalski 2003). Vertical motion estimates are made using model results for deep <span class="hlt">convection</span></p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFM.A13F0268I','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFM.A13F0268I"><span id="translatedtitle">Mature Deep <span class="hlt">Convective</span> Cloud Morphology as Observed by CloudSat</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Igel, M.; van den Heever, S. C.</p> <p>2013-12-01</p> <p>The role of oceanic deep <span class="hlt">convective</span> tropical clouds in weather and climate systems remains poorly defined for individual, deep <span class="hlt">convective</span> clouds in the tropics. It is the goal of this work to try to determine those roles by analyzing cloud length scales observed by CloudSat. It is shown that misperceptions of cloud scales could lead consequently to a misunderstanding of the roles of deep <span class="hlt">convection</span>. Using a recently developed cloud identification algorithm, CloudSat data is parsed into individual cloud objects that are present in large enough numbers to provide powerful statistics. The methodology also provides a means of counting the number of <span class="hlt">convective</span> cores within the 'pedestal' of a cloud object. As the number of <span class="hlt">convective</span> cores within a single cloud object increases, various changes in the morphology of <span class="hlt">storms</span> occur. Not only do they get wider as the number of cores increases, but the anvil base lowers and the <span class="hlt">storm</span> deepens. Correlations between different aspects of cloud morphology are evaluated with a focus on the up scale relationship of pedestals to anvils. The results implicate mesoscale organization of tropical clouds as being important for the general circulation. Finally, the sensitivity to local environmental characteristics of the cloud morphology is assessed and connections are made between the environment and the role of the cloud.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFM.A14F..05S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFM.A14F..05S"><span id="translatedtitle"><span class="hlt">Convection</span> and the Soil-Moisture Precipitation Feedback</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Schar, C.; Froidevaux, P.; Keller, M.; Schlemmer, L.; Langhans, W.; Schmidli, J.</p> <p>2014-12-01</p> <p> interannual variability over mid-latitude <span class="hlt">summer</span> climates, both over Europe and North America. It is argued that parameterized <span class="hlt">convection</span> may contribute towards such biases by overemphasizing a positive SMP feedback.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AtmRe.180..189F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AtmRe.180..189F"><span id="translatedtitle">Latent cooling and microphysics effects in deep <span class="hlt">convection</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Fernández-González, S.; Wang, P. K.; Gascón, E.; Valero, F.; Sánchez, J. L.</p> <p>2016-11-01</p> <p>Water phase changes within a <span class="hlt">storm</span> are responsible for the enhancement of <span class="hlt">convection</span> and therefore the elongation of its lifespan. Specifically, latent cooling absorbed during evaporation, melting and sublimation is considered the main cause of the intensification of downdrafts. In order to know more accurately the consequences of latent cooling caused by each of these processes (together with microphysical effects that they induce), four simulations were developed with the Wisconsin Dynamical and Microphysical Model (WISCDYMM): one with all the microphysical processes; other without sublimation; melting was suppressed in the third simulation; and evaporation was disabled in the fourth. The results show that sublimation cooling is not essential to maintain the vertical currents of the <span class="hlt">storm</span>. This is demonstrated by the fact that in the simulation without sublimation, maximum updrafts are in the same range as in the control simulation, and the <span class="hlt">storm</span> lifespan is similar or even longer. However, melting was of vital importance. The <span class="hlt">storm</span> in the simulation without melting dissipated prematurely, demonstrating that melting is indispensable to the enhancement of downdrafts below the freezing level and for avoiding the collapse of low level updrafts. Perhaps the most important finding is the crucial influence of evaporative cooling above the freezing level that maintains and enhances mid-level downdrafts in the <span class="hlt">storm</span>. It is believed that this latent cooling comes from the evaporation of supercooled liquid water connected with the Bergeron-Findeisen process. Therefore, besides its influence at low levels (which was already well known), this evaporative cooling is essential to strengthen mid-level downdrafts and ultimately achieve a quasi-steady state.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19960017272','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19960017272"><span id="translatedtitle">Evaluating and Understanding Parameterized <span class="hlt">Convective</span> Processes and Their Role in the Development of Mesoscale Precipitation Systems</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Fritsch, J. Michael; Kain, John S.</p> <p>1996-01-01</p> <p>Research efforts focused on numerical simulations of two <span class="hlt">convective</span> systems with the Penn State/NCAR mesoscale model. The first of these systems was tropical cyclone Irma, which occurred in 1987 in Australia's Gulf of Carpentaria during the AMEX field program. Comparison simulations of this system were done with two different <span class="hlt">convective</span> parameterization schemes (CPS's), the Kain-Fritsch (KF) and the Betts-Miller (BM) schemes. The second system was the June 10-11, 1985 squall line simulation, which occurred over the Kansas-Oklahoma region during the PRE-<span class="hlt">STORM</span> experiment. Simulations of this system using the KF scheme were examined in detail.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19960015952','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19960015952"><span id="translatedtitle">Evaluating and Understanding Parameterized <span class="hlt">Convective</span> Processes and Their Role in the Development of Mesoscale Precipitation Systems</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Fritsch, J. Michael (Principal Investigator); Kain, John S.</p> <p>1995-01-01</p> <p>Research efforts during the first year focused on numerical simulations of two <span class="hlt">convective</span> systems with the Penn State/NCAR mesoscale model. The first of these systems was tropical cyclone Irma, which occurred in 1987 in Australia's Gulf of Carpentaria during the AMEX field program. Comparison simulations of this system were done with two different <span class="hlt">convective</span> parameterization schemes (CPS's), the Kain-Fritsch (1993 - KF) and the Betts-Miller (Betts 1986- BM) schemes. The second system was the June 10-11 1985 squall line simulation, which occurred over the Kansas-Oklahoma region during the PRE-<span class="hlt">STORM</span> experiment. Simulations of this system using the KF scheme were examined in detail.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19850042577&hterms=water+environment&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dwater%2Benvironment%253F','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19850042577&hterms=water+environment&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dwater%2Benvironment%253F"><span id="translatedtitle">Delineating mid- and low-level water vapor patterns in pre-<span class="hlt">convective</span> environments using VAS moisture channels</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Petersen, R. A.; Uccellini, L. W.; Mostek, A.; Keyser, D. A.</p> <p>1984-01-01</p> <p>Infrared and visible imagery from VAS are used to delineate mid- and lower-tropospheric moisture fields for a variety of severe <span class="hlt">storm</span> cases in the southern and central United States. The ability of sequences of images to isolate areas of large negative vertical moisture gradients and apparent <span class="hlt">convective</span> instability prior to the onset of <span class="hlt">convective</span> <span class="hlt">storms</span> is assessed. A variety of image combination procedures are used to deduce the stability fields which are then compared with the available radiosonde data. The results for several severe <span class="hlt">storm</span> cases indicate that VAS can detect mid- and low-level mesoscale water vapor fields as distinct radiometric signals. The VAS imagery shows a strong tendency for thunderstorms to develop along the edges of bands of midlevel dryness as they overtake either preexisting or developing low-level moisture maxima. Image sequences depict the speed with which deep moist and dry layers can develop and move.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015DPS....4740005B&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015DPS....4740005B&link_type=ABSTRACT"><span id="translatedtitle">The Evolution of Saturn’s <span class="hlt">Storm</span>-Perturbed Latitudinal Band Determined from Cassini/VIMS Daytime and Nighttime Spectra</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Baines, K. H.; Sromovsky, Larry A.; Fry, Patrick M.; Moimary, Thomas W.; Badman, Sarah; Brown, Robert H.; Buratti, Bonnie J.; Clark, Roger N.; Nicholson, Philip D.; Sotin, Christophe</p> <p>2015-11-01</p> <p>Saturn’s Great <span class="hlt">Storm</span> of 2010-2011 was one of the most powerful <span class="hlt">convective</span> events ever witnessed, as indicated, for example, by its ability to deliver spectrally-identifiable water ice to the top of its <span class="hlt">convective</span> tower ~200 km above the water vapor condensation level near 20 bar (Sromovsky, L. A., et al., Icarus 226, 402-418. 2013), and by its ability over ~ 6 months to encircle the planet with apparently anvil-like ammonia clouds sheared away from the top of its <span class="hlt">convective</span> tower(s). Within a half-year after the <span class="hlt">storm</span> subsided in mid-2011, these globe-encircling anvil-like clouds appeared to have largely disappeared, replaced by a 5-micron-bright band encircling the planet over nearly the same latitude region the <span class="hlt">storm</span> generated clouds had been, indicating a dramatic decrease in the opacity of aerosols sensitive to 5-micron radiation (heat) emanating from the warm depths of the planet. Here we present quantitative results on the 5-year evolution of this <span class="hlt">storm</span>-affected, 5-micron-bright region, from its initial appearance associated with a large anti-cyclone that formed in the Spring of 2011 through May 26-27, 2015, using both daytime and nighttime Cassini/VIMS spectral maps. Compared to the “normal”, unperturbed regional cloud structure upstream of the <span class="hlt">storm</span> as observed on Feb 24, 2011, we find that the initial 5-micron-bright region on May 11, 2011 had lost ~60% of its upper-cloud (100-500 mbar) opacity (i. e., nominally, 2.7 opacity post-<span class="hlt">storm</span> at 2-microns vs 7.1 pre-<span class="hlt">storm</span>) and that the pressure of an opaque, putatively NH4SH, optically-thick “sheet” cloud dropped in altitude from a pre-<span class="hlt">storm</span> level of 2.9 bar to the 3.2-bar level post-<span class="hlt">storm</span>. Subsequently over the next 4 years, the upper-cloud region recovered half of its lost opacity, reaching ~5.6 on March 21, 2014 (and nearly recovered, to ~ 7 in our tentative May 26-27, 2015 data), corresponding to an e-folding time back to pre-<span class="hlt">storm</span> opacity of 2.7 years, but the lower cloud has dropped down to the 3</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016cosp...41E2112Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016cosp...41E2112Y"><span id="translatedtitle">General circulation modeling of the thermosphere-ionosphere during a geomagnetic <span class="hlt">storm</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yiǧit, Erdal; Immel, Thomas; Ridley, Aaron; Frey, Harald U.; Moldwin, Mark</p> <p>2016-07-01</p> <p>Using a three-dimensional general circulation model (GCM) of the upper atmosphere, we investigate the response of the thermosphere-ionosphere system to the August 2011 major geomagnetic <span class="hlt">storm</span>. The GCM is driven by measured <span class="hlt">storm</span>-time input data of the Interplanetary Magnetic Field (IMF), solar activity, and auroral activity. Simulations for quiet steady conditions over the same period are performed as well in order to assess the response of the neutral and plasma parameters to the <span class="hlt">storm</span>. During the <span class="hlt">storm</span>, the high-latitude mean ion flows are enhanced by up to ~150%. Overall, the global mean neutral temperature increases by up to 15%, while the maximum thermal response is higher in the winter Southern Hemisphere at high-latitudes than the <span class="hlt">summer</span> Northern Hemisphere: 40% vs. 20% increase in high-latitude mean temperature, respectively. The global mean Joule heating of the neutral atmosphere increases by more than a factor of three. There are distinct hemispheric differences in the magnitude and morphology of the horizontal ion flows and thermospheric circulation during the different phases of the <span class="hlt">storm</span>. The thermospheric circulation demonstrates the largest amount of hemispheric differences during the later stages of the <span class="hlt">storm</span>. Dynamical diagnostics show that advective forcing contributes to hemispheric differences.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19900065483&hterms=plasma+nitrogen&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dplasma%2Bnitrogen','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19900065483&hterms=plasma+nitrogen&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dplasma%2Bnitrogen"><span id="translatedtitle">Plasma <span class="hlt">convection</span> in Neptune's magnetosphere</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Selesnick, R. S.</p> <p>1990-01-01</p> <p>The magnetosphere of Neptune changes its magnetic configuration continuously as the planet rotates, leading to a strong modulation of the <span class="hlt">convection</span> electric field. Even though the corotation speed is considerably larger, the modulation causes the small <span class="hlt">convection</span> speed to have a cumulative effect, much like the acceleration of particles in a cyclotron. A model calculation shows that plasma on one side of the planet <span class="hlt">convects</span> out of the magnetosphere in a few planetary rotations, while on the other side it <span class="hlt">convects</span> slowly planetward. The observation of nitrogen ions from a Triton plasma torus may provide a critical test of the model.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20110007249','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20110007249"><span id="translatedtitle">Large Geomagnetic <span class="hlt">Storms</span>: Introduction to Special Section</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Gopalswamy, N.</p> <p>2010-01-01</p> <p>Solar cycle 23 witnessed the accumulation of rich data sets that reveal various aspects of geomagnetic <span class="hlt">storms</span> in unprecedented detail both at the Sun where the <span class="hlt">storm</span> causing disturbances originate and in geospace where the effects of the <span class="hlt">storms</span> are directly felt. During two recent coordinated data analysis workshops (CDAWs) the large geomagnetic <span class="hlt">storms</span> (Dst < or = -100 nT) of solar cycle 23 were studied in order to understand their solar, interplanetary, and geospace connections. This special section grew out of these CDAWs with additional contributions relevant to these <span class="hlt">storms</span>. Here I provide a brief summary of the results presented in the special section.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007EOSTr..88...93F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007EOSTr..88...93F"><span id="translatedtitle"><span class="hlt">Storm</span> Impacts on Potential Pathogens in Estuaries</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Fries, J. Stephen; Noble, Rachel T.; Kelly, Ginger M.; Hsieh, Jennifer L.</p> <p>2007-02-01</p> <p>Estuarine and coastal environments are susceptible to a variety of changes driven by tropical <span class="hlt">storms</span> and hurricanes. The 2005 Atlantic hurricane season impressed upon the public the devastating impacts of <span class="hlt">storms</span> on coastal populations and the possible social and public health costs. <span class="hlt">Storm</span> surges and subsequent flooding have the potential to redistribute water and associated contaminants, including a wide range of chemicals and microorganisms. While this impact is difficult to observe through monitoring during larger <span class="hlt">storms</span>, smaller <span class="hlt">storms</span> provide opportunities to observe the mechanisms responsible for contaminant and microbial transport.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2010AGUFMAE31B..04K&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2010AGUFMAE31B..04K&link_type=ABSTRACT"><span id="translatedtitle">Lightning Mapping and Electric Field Change Observations of a Stationary New Mexico <span class="hlt">Storm</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Krehbiel, P. R.; Rison, W.; Hunyady, S. J.; Edens, H. E.; Sonnenfeld, R. G.; Aulich, G. D.</p> <p>2010-12-01</p> <p> charge transfer of these CC discharges were noticeably larger than that of non-CC flashes. The CCs were associated with an uninterrupted, continuously-spreading and highly-branched dendritic structure of the VHF sources in many directions within the <span class="hlt">storm</span>'s negative charge region. Finally, the <span class="hlt">storm</span> did not produce screening discharges between the upper positive and cloud-top negative screening charges, or upward jets above the <span class="hlt">storm</span> top, consistent with turbulent mixing of the screening charge into the upper positive in the strongly <span class="hlt">convective</span> <span class="hlt">storm</span>. A number of bolt-from-the-blue (BFB) discharges were produced by the <span class="hlt">storm</span>, also consistent with depletion of the upper positive charge region by turbulent mixing of the screening charge.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016RSPSA.47260480F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016RSPSA.47260480F"><span id="translatedtitle">Bidispersive-inclined <span class="hlt">convection</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Falsaperla, Paolo; Mulone, Giuseppe; Straughan, Brian</p> <p>2016-08-01</p> <p>A model is presented for thermal <span class="hlt">convection</span> in an inclined layer of porous material when the medium has a bidispersive structure. Thus, there are the usual macropores which are full of a fluid, but there are also a system of micropores full of the same fluid. The model we employ is a modification of the one proposed by Nield & Kuznetsov (2006 Int. J. Heat Mass Transf. 49, 3068-3074. (doi:10.1016/j.ijheatmasstransfer.2006.02.008)), although we consider a single temperature field only.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/12460481','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/12460481"><span id="translatedtitle">Zoned mantle <span class="hlt">convection</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Albarède, Francis; Van Der Hilst, Rob D</p> <p>2002-11-15</p> <p>We review the present state of our understanding of mantle <span class="hlt">convection</span> with respect to geochemical and geophysical evidence and we suggest a model for mantle <span class="hlt">convection</span> and its evolution over the Earth's history that can reconcile this evidence. Whole-mantle <span class="hlt">convection</span>, even with material segregated within the D" region just above the core-mantle boundary, is incompatible with the budget of argon and helium and with the inventory of heat sources required by the thermal evolution of the Earth. We show that the deep-mantle composition in lithophilic incompatible elements is inconsistent with the storage of old plates of ordinary oceanic lithosphere, i.e. with the concept of a plate graveyard. Isotopic inventories indicate that the deep-mantle composition is not correctly accounted for by continental debris, primitive material or subducted slabs containing normal oceanic crust. Seismological observations have begun to hint at compositional heterogeneity in the bottom 1000 km or so of the mantle, but there is no compelling evidence in support of an interface between deep and shallow mantle at mid-depth. We suggest that in a system of thermochemical <span class="hlt">convection</span>, lithospheric plates subduct to a depth that depends - in a complicated fashion - on their composition and thermal structure. The thermal structure of the sinking plates is primarily determined by the direction and rate of convergence, the age of the lithosphere at the trench, the sinking rate and the variation of these parameters over time (i.e. plate-tectonic history) and is not the same for all subduction systems. The sinking rate in the mantle is determined by a combination of thermal (negative) and compositional buoyancy and as regards the latter we consider in particular the effect of the loading of plates with basaltic plateaux produced by plume heads. Barren oceanic plates are relatively buoyant and may be recycled preferentially in the shallow mantle. Oceanic plateau-laden plates have a more pronounced</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/12460481','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/12460481"><span id="translatedtitle">Zoned mantle <span class="hlt">convection</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Albarède, Francis; Van Der Hilst, Rob D</p> <p>2002-11-15</p> <p>We review the present state of our understanding of mantle <span class="hlt">convection</span> with respect to geochemical and geophysical evidence and we suggest a model for mantle <span class="hlt">convection</span> and its evolution over the Earth's history that can reconcile this evidence. Whole-mantle <span class="hlt">convection</span>, even with material segregated within the D" region just above the core-mantle boundary, is incompatible with the budget of argon and helium and with the inventory of heat sources required by the thermal evolution of the Earth. We show that the deep-mantle composition in lithophilic incompatible elements is inconsistent with the storage of old plates of ordinary oceanic lithosphere, i.e. with the concept of a plate graveyard. Isotopic inventories indicate that the deep-mantle composition is not correctly accounted for by continental debris, primitive material or subducted slabs containing normal oceanic crust. Seismological observations have begun to hint at compositional heterogeneity in the bottom 1000 km or so of the mantle, but there is no compelling evidence in support of an interface between deep and shallow mantle at mid-depth. We suggest that in a system of thermochemical <span class="hlt">convection</span>, lithospheric plates subduct to a depth that depends - in a complicated fashion - on their composition and thermal structure. The thermal structure of the sinking plates is primarily determined by the direction and rate of convergence, the age of the lithosphere at the trench, the sinking rate and the variation of these parameters over time (i.e. plate-tectonic history) and is not the same for all subduction systems. The sinking rate in the mantle is determined by a combination of thermal (negative) and compositional buoyancy and as regards the latter we consider in particular the effect of the loading of plates with basaltic plateaux produced by plume heads. Barren oceanic plates are relatively buoyant and may be recycled preferentially in the shallow mantle. Oceanic plateau-laden plates have a more pronounced</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFMOS52A..02N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFMOS52A..02N"><span id="translatedtitle">Multi-Decadal Modulations in the Variability of the East Asian <span class="hlt">Summer</span> Monsoon</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Nakamura, H.; Machimura, T.; Ogawa, S.; Kosaka, Y.; Nishii, K.; Miyasaka, T.</p> <p>2015-12-01</p> <p>The East Asian <span class="hlt">summer</span> monsoon fluctuates from its climatological activity on monthly and interannual time scales, and the most dominant pattern of the variability is known as the Pacific-Japan (PJ) pattern. Characterized by a meridional teleconnection in anomalous activity of the Meiyu/Baiu rainband, tropical <span class="hlt">storms</span> and a surface subtropical anticyclone (the Bonin High) in between, the PJ pattern exerts substantial influence on summertime climatic conditions over East Asia and the western North Pacific. Despite the recent warming trend observed in its background state, no assessment thus far has been made on how substantially the PJ has undergone, if any, multi-decadal modulations in its structure and/or dominance. Through an EOF analysis applied to a new dataset of global atmospheric reanalysis (JRA-55), the predominance of the PJ pattern is confirmed as being extracted in the leading EOF of lower-tropospheric monthly vorticity anomalies over 55 recent years. Both efficient barotropic/baroclinic energy conversion from the climatological-mean state and efficient generation of available potential energy through anomalous <span class="hlt">convective</span> activity over the tropical western Pacific are shown to be essential for the maintenance of the monthly atmospheric anomalies of the PJ pattern over the entire 55-year period. At the same time, however, the same EOF analysis as above but applied separately to each of the sub-periods reveals a distinct signature of long-term modulations in amplitude and thus the dominance of the PJ pattern. While being extracted in the first EOF up to the 1980s, the PJ pattern is extracted in the second EOF in the period since the 1990s with marked reductions in both the variance fraction explained and the efficiency of energy conversion/generation. The resultant modulations of the summertime meridional teleconnection are also discussed with implications for future changes.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016JGRA..121.3421N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016JGRA..121.3421N"><span id="translatedtitle">Middle- and low-latitude ionosphere response to 2015 St. Patrick's Day geomagnetic <span class="hlt">storm</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Nava, B.; Rodríguez-Zuluaga, J.; Alazo-Cuartas, K.; Kashcheyev, A.; Migoya-Orué, Y.; Radicella, S. M.; Amory-Mazaudier, C.; Fleury, R.</p> <p>2016-04-01</p> <p>This paper presents a study of the St Patrick's Day <span class="hlt">storm</span> of 2015, with its ionospheric response at middle and low latitudes. The effects of the <span class="hlt">storm</span> in each longitudinal sector (Asian, African, American, and Pacific) are characterized using global and regional electron content. At the beginning of the <span class="hlt">storm</span>, one or two ionospheric positive <span class="hlt">storm</span> effects are observed depending on the longitudinal zones. After the main phase of the <span class="hlt">storm</span>, a strong decrease in ionization is observed at all longitudes, lasting several days. The American region exhibits the most remarkable increase in vertical total electron content (vTEC), while in the Asian sector, the largest decrease in vTEC is observed. At low latitudes, using spectral analysis, we were able to separate the effects of the prompt penetration of the magnetospheric <span class="hlt">convection</span> electric field (PPEF) and of the disturbance dynamo electric field (DDEF) on the basis of ground magnetic data. Concerning the PPEF, Earth's magnetic field oscillations occur simultaneously in the Asian, African, and American sectors, during southward magnetization of the Bz component of the interplanetary magnetic field. Concerning the DDEF, diurnal magnetic oscillations in the horizontal component H of the Earth's magnetic field exhibit a behavior that is opposed to the regular one. These diurnal oscillations are recognized to last several days in all longitudinal sectors. The observational data obtained by all sensors used in the present paper can be interpreted on the basis of existing theoretical models.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014PhDT.......185S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014PhDT.......185S"><span id="translatedtitle">Observational analysis of the interaction between a baroclinic boundary and supercell <span class="hlt">storms</span> on 27 April 2011</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sherrer, Adam Thomas</p> <p></p> <p>A thermal boundary developed during the morning to early afternoon hours on 27 April as a result of rainfall evaporation and shading from reoccurring deep <span class="hlt">convection</span>. This boundary propagated to the north during the late afternoon to evening hours. The presence of the boundary produced an area more conducive for the formation of strong violent tornadoes through several processes. These processes included the production of horizontally generated baroclinic vorticity, increased values in <span class="hlt">storm</span>-relative helicity, and decreasing lifting condensation level heights. Five supercell <span class="hlt">storms</span> formed near and/or propagated alongside this boundary. Supercells that interacted with this boundary typically produced significant tornadic damage over long distances. Two of these supercells formed to the south (warm) side of the boundary and produced a tornado prior to crossing to the north (cool) side of the boundary. These two <span class="hlt">storms</span> exhibited changes in appearance, intensity, and structure. Two other supercells formed well south of the boundary. These two <span class="hlt">storms</span> remained relatively weak until they interacted with the boundary. These <span class="hlt">storms</span> then rapidly intensified and produced tornadoes. Supercells that formed well into the cool side of the boundary either did not produce tornadoes or the tornadoes were determined to be weak in nature.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009pcms.confE..26S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009pcms.confE..26S"><span id="translatedtitle"><span class="hlt">Storms</span> of Mediterranean and Atlantic legends</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Schoenenwald, N.; Tabeaud, M.</p> <p>2009-09-01</p> <p>Weather extremes and notably wind <span class="hlt">storms</span> are very often the channel ones since they are suspected of being the outward signs of climate change. However, even if audiovisual medias talk about wind <span class="hlt">storms</span> in a very similar way, tales and legends stories account for the richness of their representations. Coastal and insular regions, whatever Atlantic or Mediterranean, are the ones where wind <span class="hlt">storms</span> are most mentioned. The comparison between the tales and legends of these two regions, with distinct climatic characteristics, allows to underline the similarities and dissimilarities about the impregnation (or impact) of wind <span class="hlt">storms</span> on these territories. Winds and <span class="hlt">storms</span> distinguish spaces through vocabulary which can be peculiar to a region. Nevertheless, they also bring them together because above the local cultures is the human thought upon which wind <span class="hlt">storms</span> create comparable perceptions, whatever the region. Key words: wind <span class="hlt">storms</span>, Mediterranean regions, Atlantic regions, perceptions, representations.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li class="active"><span>25</span></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_25 --> <center> <div class="footer-extlink text-muted"><small>Some links on this page may take you to non-federal websites. 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