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1

Convection index as a tool for trend analysis of intense summer storms in Switzerland  

NASA Astrophysics Data System (ADS)

Convective summer thunderstorms are generally responsible for the most devastating floods in urban and small natural catchments. In this study we focus on the identification of the nature and magnitude of changes in the properties of intense summer storms of convective character in Switzerland in the last three decades. The study is based on precipitation records from the SwissMetNet (MeteoSwiss) network at 63 stations that cover altitudes ranging from 200 up to 3300 m a.s.l. over the period 1981-2012 (32 years). Additionally, the same stations also measure the number of lightning strikes within a range of 30 km from each station. In an accompanying contribution we describe the method how intensive summer storms can be reliably selected out of all storms in long and high resolution precipitation time series. On the basis of the statistical distributions and dependence among key storm characteristics at the event scale (total rainfall depth R, storm duration D, and peak intensity I) and using high resolution lightning data as a surrogate we defined a threshold intensity I* that differentiates between the events accompanied with lightning with an acceptably small probability of misclassification. This allowed us to identify intense summer events with convective character as those where I > I* regardless of their duration or total rainfall depth. The current study makes use of the threshold intensity I* for the definition of a seasonal convection index at each station (Llasat, 2001). This index gives us a measure of 'convectiveness', i.e. the total precipitation depth coming from convective storms relative to the total precipitation depth of all summer storms. We computed the convection index at all 63 stations and analyzed the series for trends. We found that the seasonal convection index increases at most of the stations in Switzerland and in approximately 20% of the cases this increase is statistically significant. This is likely a consequence of the fact that the number of summer storms exceeding the threshold I* also shows an increasing tendency with a similar percentage of statistically significant changes. Although our analysis indicates an increasing tendency in the intensity and frequency of summer storms with convective character in Switzerland, it is not yet clear whether these can be traced to causal factors such as atmospheric warming, etc. This remains an open research question.

Gaal, Ladislav; Molnar, Peter; Szolgay, Jan

2013-04-01

2

Historical Overview of Severe Convective Storms Research  

Microsoft Academic Search

An overview of the history of research related to severe convective storms is presented, with a particular emphasis on the connection between this research and forecasting. Forecasting and basic research in severe convective storms have been intertwined since the very beginnings of modern severe convective storms research - that is, since the end of World War II. There are good

CHARLES A. DOSWELL

2007-01-01

3

Severe convective storms and associated phenomena in Hungary  

Microsoft Academic Search

Convective activity dominates the weather of Hungary in the summer. Especially during the first part of the summer, the frequency of severe thunderstorms grows and associated phenomena such as wind storms, hail, sometimes even tornadoes cause serious damage. In this paper, an overview of the severe thunderstorm situation in the Carpathian Basin is presented with a focus on the most

Ákos Horváth; István Geresdi

2001-01-01

4

Convective Ionospheric Storms: A Review  

NASA Astrophysics Data System (ADS)

Equatorial spread F (ESF) was discovered almost a century ago using the first radio wave instrument designed to study the upper atmosphere: the ionosonde. The name came from the appearance of reflections from the normally smooth ionosphere, which were spread over the altitude frequency coordinates used by the instrument. Attempts to understand this phenomenon in any depth activated such tools as radars and in situ probes such as rockets and satellites in the 1960s. Over the next 15 years, these tools expanded our experimental understanding enormously, and new nonlinear theoretical methods developed in the late 1970s, which led to proposing a name revision from ESF to convective ionospheric storms. Interest in these phenomena continues, but a new, practical aspect has developed from the associated turbulence effects on communications (transionosphere) and navigation (GPS). The first satellite to specifically investigate this problem and the associated goal of predicting occurrences is under the umbrella of the Communications/Navigation Outage Forecast System (C/NOFS). In contemplating the successful first years of the C/NOFS program, reviewing the state of the art in our knowledge of convective ionospheric storms seems appropriate. We also present some initial results of this satellite program. A major goal of the National Space Weather Program, and of C/NOFS, is predicting these storms, analogous to thunderstorms in the lower atmosphere due to their adverse effects on communication and navigation signals. Although ambitious, predictive capability is a noble and important goal in the current technological age and is potentially within our reach during the coming decade.

Kelley, Michael C.; Makela, Jonathan J.; de La Beaujardière, Odile; Retterer, John

2011-06-01

5

Principles of Convection III: Shear and Convective Storms  

NSDL National Science Digital Library

This module discusses the role of wind shear in the structure and evolution of convective storms. Using the concept of horizontal vorticity, the module demonstrates how shear enhances uplift, leading to longer-lived supercell and multicell storms. The module also explores the role of shear in the development of mesoscale convective systems, including bow echoes and squall lines. Most of the material in this module previously appeared in the COMET modules developed with Dr. Morris Weisman. This version includes a concise summary for quick reference and a final exam to test your knowledge.

Spangler, Tim

2003-10-01

6

Polarimetric observations of monsoon convective storms in south Taiwan  

NASA Astrophysics Data System (ADS)

Polarimetric radar has been used to observe the kinematic, dynamic and microphysical structure of severe convective storms in south Taiwan during the Southwest Monsoon Experiment (SoWMEX), May-June 2008. Two types of convective storms are studied, the ocean-originated and the land-originated, respectively. The gross features of these two types of convections showed pronounced differences in terms of convective vs stratiform precipitation area and the lightning density. The ocean-type storms showed more stratiform precipitation than convective and the land-type storms showed the opposite. The difference of this feature may be caused by the different dynamic processes related to the environment conditions.

Jou, Jong-Dao

2013-04-01

7

Urban Aerosol Impacts on Downwind Convective Storms  

Microsoft Academic Search

The impacts of urban-enhanced aerosol concentrations on convective storm development and precipita- tion over and downwind of St. Louis, Missouri, are investigated. This is achieved through the use of a cloud-resolving mesoscale model, in which sophisticated land use processes and aerosol microphysics are both incorporated. The results indicate that urban-forced convergence downwind of the city, rather than the presence of

Susan C. van den Heever; William R. Cotton

2007-01-01

8

A Convective Storm Matrix: Buoyancy/Shear Dependencies  

NSDL National Science Digital Library

In order to help forecasters build a strategy for anticipating convective storm structures, their evolution, and the potential for severe weather, A Convective Storm Matrix provides learners the opportunity for extensive exploration of the relationship between a storm's environment and its structure. The matrix is composed of 54 four-dimensional numerical simulations based on the interactions of 16 different hodographs and 4 thermodynamic profiles. By comparing animated displays of these simulations, learners are able to discern the influences of varying buoyancy and vertical wind shear profiles on storm structure and evolution. A series of questions guides the exploration and helps to reveal key storm/environment relationships evident in the matrix. A synopsis of the physical processes that control storm structure, as well as the current conceptual models of key convective storms types, is included for reference.

Spangler, Tim

1998-01-01

9

Seamless Probabilistic Forecasting of Convective Storms  

NASA Astrophysics Data System (ADS)

Different methods are used to provide forecasts of precipitation with different lead times, and a major challenge is to provide seamless forecasts across the range of times of interest to a decision maker. Firstly, the detailed precipitation map obtained from Radar can be extrapolated into the future by advecting the precipitation pattern ("Nowcasting"), although the forecast quality degrades rapidly in the first hours because the dynamics of the storm are not accurately represented. At longer lead times numerical weather prediction ("NWP") is superior since it includes dynamical effects, but cannot match the skill of nowcasting in the first few hours due to the difficulty of assimilating precipitation observations. A seamless combination of these methods requires knowledge of their errors, and is difficult because the predictability depends strongly on the meteorological situation. However it is now becoming possible with the availability of probabilistic predictions from ensembles of high resolution forecasts. These concepts will be illustrated using ensemble forecasts of convective events with the 2.8 km resolution COSMO-DE model nested within different forecasts from the COSMO-LEPS ensemble. Probabilistic nowcasts are produced using the Cb-TRAM system that tracks convective a convective cloud field using an optical flow method. The images are then extrapolated forward in time and probabilistic forecasts are generated using the local Lagrangian method. Examples will be shown to illustrate how the forecast skill of the two methods is influenced by the inherent predictability of the meteorological situation, in particular the degree of control of convective by the synoptic flow.

Craig, G. C.

2009-04-01

10

Environmental Influences on Precipitation Intensity in Simulated Convective Storms  

NASA Astrophysics Data System (ADS)

Anticipating whether or not convective storms will produce heavy precipitation is a challenging forecast problem. In this paper, we utilize a set of over 200 unique cloud-resolving numerical simulations to investigate vertical profiles of temperature, humidity, and wind that favor increased surface precipitation intensity. Strong correlations are found to exist between surface rain and hail mixing ratios and deep tropospheric wind shear, with greater shears frequently associated with better organized convection and more precipitation. Raising the height of the level of free convection (LFC) is also somewhat correlated with increased surface rain and hail, which is enhanced by greater updraft overturning efficiency compared to storms in low LFC environments. Storms in cooler environments having reduced amounts of precipitable water (PW) nevertheless display greater precipitation efficiency and thus produce almost as much precipitation as storms in warmer, moister environments with high PW. Interestingly, surface rainfall exhibits no preferential increase as convective available potential energy (CAPE) increases. Possible changes to storm rainfall production in the presence of environmental change will also be discussed.

Kirkpatrick, C.; McCaul, E. W.

2009-05-01

11

The Anatomy of a Continental Tropical Convective Storm  

Microsoft Academic Search

This study provides a very clear picture of the microphysics and flow field in a convective storm in the Rondonia region of Brazil through a synthesis of observations from two unique radars, measurements of the surface drop size distribution (DSD), and particle types and sizes from an aircraft penetration. The primary findings are 1) the growth of rain by the

David Atlas; Christopher R. Williams

2003-01-01

12

Modes of isolated, severe convective storm formation along the dryline  

SciTech Connect

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.

Bluestein, H.B.; Parker, S.S. (Univ. of Oklahoma, Norman (United States))

1993-05-01

13

Environmental Influences on Vorticity Production in Simulated Convective Storms  

NASA Astrophysics Data System (ADS)

This paper explores the influence of basic environmental parameters on mid-level and low-level vorticity production in a large set of simulated convective storms. Results show that the primary environmental conditions that increase midlevel vorticity are: substantial deep layer tropospheric wind shear; large amounts of convective available potential energy (CAPE); and a high level of free convection (LFC). These conditions are, to a significant degree, the same as those that enhance updraft velocity. About 79% of the interexperiment variance in midlevel vorticity can be attributed to the seven environmental parameters studied herein, when combined in a multiple linear regression form. Vorticity amounts near the surface are explained less well (64%), and are again correlated with stronger wind shear, but, contrary to vorticity aloft, with lower lifting condensation level (LCL) and LFC heights. Near-surface vorticity is also found to correlate strongly with low-level updraft intensity, but in a distinctly nonlinear sense. CAPE and its vertical distribution also explain much of the intra-experiment temporal variability in mid-level vorticity that is observed. This paper offers evidence suggesting that studies of convection that focus exclusively on the CAPE-shear parameter space may be unable to explain some important relationships between a storm's rotational characteristics and its environment.

Kirkpatrick, C.; McCaul, E. W., Jr.

2009-12-01

14

Global-scale observations of ionospheric convection during geomagnetic storms  

NASA Astrophysics Data System (ADS)

The global effects on the ionosphere during periods of intense geomagnetic activity associated with geomagnetic storms are investigated using the Super Dual Auroral Radar Network (SuperDARN). The influence of the main and recovery phases of geomagnetic storms on ionospheric properties such as backscatter occurrence rates, velocity distributions, and convection patterns are presented. The evolution of magnetosphere and ionosphere parameters during the storms did not depend on the origin of the storm (e.g., a coronal mass ejection or a corotating interaction region). Instead, there was a continuum of response to the intensity of the driver. For example, we found a clear relationship between the most negative value of the southward component of the interplanetary magnetic field (IMF Bz) and the most negative value of the Sym-H index, which marks the end of the main phase of a storm. This is one of the first superposed epoch studies that analyzes the sunward/antisunward line-of-sight velocity as a function of magnetic local time for geomagnetic storms of various intensities. In the noon sector, before and during the main phase of the storms, the SuperDARN radars recorded faster antisunward ionospheric plasma drifts together with a significant increase in the number of ionospheric echoes. This is consistent with the expected increase in soft particle precipitation in the noon sector and with the reconnection electric field that occurs when the IMF Bz is strongly negative, as is the case during the main phase of storms. The SuperDARN echo occurrence in the noon sector returned to prestorm values early in the recovery phase. The overall response was similar in the midnight sector, except that the peak echo occurrence for the most intense storms was limited to a narrower time interval centered on the end of the main phase. There were reductions in the strong antisunward flows near local midnight observed during the main phase and early in the recovery phase, particularly for the intense storm class. Strong electric fields are applied in the nightside ionosphere during storms, and the decameter structures from which SuperDARN scatter are more easily produced. However, in regions of energetic auroral precipitation and after a long exposure to strong electric fields, there is often a reduction in SuperDARN echoes due to absorption or changes in radio wave propagation.

Gillies, D. M.; McWilliams, K. A.; St. Maurice, J.-P.; Milan, S. E.

2011-12-01

15

Global modeling of convection electric potentials during geomagnetic storms  

NASA Astrophysics Data System (ADS)

Due to satellite and instrumental limitations, in situ magnetospheric electric field measurements are only available at isolated locations during stormtime conditions. A global view of the inner magnetospheric convection electric field can be obtained by mapping ionospheric potentials into the equatorial plane. A mapping procedure for AMIE (Assimilative Mapping of Ionospheric Electrodynamics) ionospheric potentials MACEP (Mapping of AMIE Convection Electric Potentials) is used to obtain convection patterns for Jan. 10, 1997 and May 15, 1997 geomagnetic storms. The results are compared with the widely used empirical Volland-Stern model and the mapping of Weimer ionospheric potentials. The MACEP results are in reasonable agreement with limited electric field measurements from the EFI instrument on the Polar spacecraft and LANL measurements of thermal ion velocities at geosynchronous orbit during pre-storm and recovery phase conditions. However, the inner boundary condition employed in the current version of AMIE is unable to reproduce the magnitude of the penetrating electric fields observed in the inner magnetosphere during the main phase of a storm. The addition of a penetration electric field associated with an asymmetric ring current in the dusk sector greatly improved MACEP results in the duskside low L region. While the gross temporal evolution of the large-scale potential drop across the magnetosphere is similar in all three models (MACEP, Volland-Stern, and Weimer), detailed inter-comparison shows that the MACEP procedure is capable of resolving highly variable and relatively small-scale features of the electric field that are not treated by the Volland-Stern model nor seen from the Weimer mapping. MACEP results display many features of the inner magnetosphere during storms including the penetration of convection to low L values due to the increase in southward IMF Bz, the breakdown of the shielding electric field during periods of enhanced auroral zone Hall conductivity, the local time dependence of the penetration electric field throughout the storm, evidence of overshielding as a result of IMF Bz northward turnings following a period of small negative IMF Bz, and strong earthward flows from the duskside flanks during the main phase. (Abstract shortened by UMI.)

Boonsiriseth, Amy

16

Ozone transport by mesoscale convective storms in western Senegal  

NASA Astrophysics Data System (ADS)

During the rainy period of August and September 2006, a study was conducted to investigate the prevailing diurnal patterns of ozone in rural western Senegal. Ground-level ozone was continuously measured with gas analyzers. During selected days, ozone and atmospheric thermodynamic measurements were also made in the troposphere. Ground-level ozone exhibited diurnal variations in response to the local photochemical processes and vertical transport. Maximum ground-level ozone mixing ratios reached 30 parts per billion on a volume basis (ppbv) during 1200-1600 h, local time. Deviations from the expected diurnal ozone patterns were observed during most rainy days. The observed deviations were manifested as ozone increases which were associated with downdrafts of mesoscale convective storms. The magnitude of the ozone increases depended on the strength of convective velocities which exceeded 10 m s -1. Downdrafts increased the ground-level ozone by 10-30 ppbv. Based on field observation in Senegal and elsewhere, a conceptual model is presented to explain the influences of convective storms on the redistribution of ozone in the continental troposphere.

Grant, Deanne D.; Fuentes, Jose D.; DeLonge, Marcia S.; Chan, Stephen; Joseph, Everette; Kucera, Paul; Ndiaye, Seydi A.; Gaye, Amadou T.

17

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

PubMed

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

Grinn-Gofro?, Agnieszka; Strzelczak, Agnieszka

2012-11-19

18

Changes in concentration of Alternaria and Cladosporium spores during summer storms  

NASA Astrophysics Data System (ADS)

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.

Grinn-Gofro?, Agnieszka; Strzelczak, Agnieszka

2013-09-01

19

Severe convective storms and United States climate change in the latter half of the twentieth century  

NASA Astrophysics Data System (ADS)

Severe local storms generated by atmospheric convection and enhanced by wind shear may increase in frequency within the United States, forced by increased surface temperature and other climate changes documented during the 20th Century. However, archives of thunderstorm and tornado events may not accurately represent the climate system, because storm reporting has been influenced by changing detection technologies, enhanced public awareness, and, most importantly, population patterns. Given the possible biases in available storm data and likely underreporting in earlier decades, the climatology of these events over the last ˜50 years was addressed in two ways. First, temporal changes in severe weather potential across the coterminous United States were explored using sounding-derived atmospheric stability indices, by calculating trends in the number of days registering extreme values of each selected index (the Lifted Index, the K-Index, the Severe Weather Threat Index, and Convective Available Potential Energy). This analysis was performed for spring and summer seasons only, when the vast majority of severe weather events occur. Second, spatial and temporal patterns in observed U.S. tornadoes were elucidated, and their relationship to population patterns was assessed with several methods, including: a comparison of trends in population density and tornado density (tornadoes per unit area) for all U.S. counties, the calculation of spatial and temporal correlations between the two variables, and the formal definition of a population bias in the tornado record. Observed county tornado densities were then adjusted for population bias, and the corrected changes in tornado occurrence were mapped. Because population is not the only factor that could produce a spurious rise in the storm record, the average increase in population-corrected tornado patterns was removed, in order to highlight possible climate-driven changes. These investigations revealed that the number of extremely unstable days, and therefore the potential for severe storm and tornado development, has increased over the eastern two-thirds of the nation. The stability index trends were quite consistent in the U.S. plains and southern regions in summer, while few changes in severe weather frequency were suggested in the west. Increases in observed tornadoes also emerged over most of the country. These changes appear to be partly related to population increases in Colorado, the southwest, the Gulf Coast, Florida, and around major urban centers. (Abstract shortened by UMI.)

Derubertis, Diana Marie

20

Initiation of a convective dust storm over North India on 21 April 2010 inferred using satellite data  

NASA Astrophysics Data System (ADS)

Dust storms commonly occur during the pre-monsoon (summer) season in north and northwest parts of India. Characteristics of dust events of the pressure gradient type are well understood. However, comprehensive studies on mechanism of convective dust storms in India are few. A convective dust storm which occurred on 21 April 2010 in association with a western disturbance over North India was hence studied. In the absence of in situ data, we used available satellite data to study the event. Dust storm that occurred on 20 April 2010 on the surface of the Thar Desert transported dust to northern and northwestern parts of India (Rajasthan, Haryana, Delhi and some parts of Uttar Pradesh). This formed a background of aerosols that affected the thunderstorm formed in association with western disturbance and the strong updraft in the thunderstorm carried the dust lingering in the atmosphere to higher altitudes. Large amount of aerosols carried to higher altitude suppressed the chance of precipitation by affecting the cloud top microphysics. Enhancement in evaporation due to an increase in aerosol concentration and strong downdrafts during dissipation of the thunderstorm resulted in emission of dust particles which led to the convective dust event of 21 April 2010.

Desouza, Nirmala Devidas; Kurchania, Rajnish; Qureshi, Muhammad Shums

2013-10-01

21

Severe storms and nowcasting in the Carpathian basin  

Microsoft Academic Search

Summer weather can cause severe situations in the Carpathian basin. Convective events such as thunderstorms (sometimes tornado-producing supercells) and squall lines occur frequently during the summer. In the first part of this paper, some typical convective storm events and their atmospheric conditions are presented. Most of the convective storms are associated with cold fronts but the most dangerous phenomena can

Ákos Horváth; István Geresdi

2003-01-01

22

Numerical modeling of severe convective storms occurring in the Carpathian Basin  

NASA Astrophysics Data System (ADS)

Squall lines often cause serious damages due to the strong surface outflow, hail, or heavy precipitation in Hungary every summer. Squall lines in the Carpathian Basin can be classified into two main categories: pre-frontal squall-lines and frontal convective lines. In this paper, these two types of severe mesoscale phenomena are investigated using the high resolution numerical weather prediction model, the MM5. The case study for the first type of convective systems occurred on 18th May 2005 when two main convective lines with their embedded severe storms formed daytime and caused high-velocity wind events and extensive damages in the eastern part of Hungary. The second case study is a frontal squall line that hit Budapest on 20th August 2006 and the associated high precipitation (HP) supercells reached the capital of Hungary at same time when the traditional Constitution Day firework began. The consequences were catastrophic: five people were killed and more than one thousand were injured due to the extreme weather. The non-hydrostatic high resolution MM5 model was able to simulate and catch the severe weather events occurred on the days under discussion. Moreover, the model was able to compute the detailed structure of the supercells embedded in thunderstorm lines. By studying the equivalent potential temperature (EPT) fields at lower levels, we state that in the prefrontal case, there is a competition between the supercell thunderstorms for the wet and warm air. A thunderstorm that can collect the wet and warm air from larger area will have longer lifetime and more intense updraft. In the second case, the frontal squall lines, the movement and the behavior of the supercell storms embedded in the line was highly determined by the synoptic-scale motions and less affected by the EPT field of the prefrontal masses.

Horváth, Á.; Geresdi, I.; Németh, P.; Csirmaz, K.; Dombai, F.

23

Intense summer storms identified on the basis of lightning strikes in Switzerland  

NASA Astrophysics Data System (ADS)

A differentiation between the two basic types of precipitation, i.e. convective and stratiform, is of great importance in hydrological modeling and engineering practice. In this study we propose a methodology for the estimation of the character of precipitation events exclusively on the basis of local high resolution meteorological data (lightning strikes, precipitation), and not taking into consideration any information on the character of precipitation on the basis of remote measurements (radars, satellites). Identification of convective events is based on the hypothesis that thunderstorms with strong convective lifting are commonly associated with lightning. The study is based on precipitation depth measurements at a 10-min time step with a heated tipping-bucket gauge with tip resolution 0.1 mm from the SwissMetNet (MeteoSwiss) network at 63 stations that cover altitudes ranging from 200 up to 3300 m a.s.l. over the period 1981-2012 (32 years). Additionally, the same stations also measure the number of lightning strikes within a range of 30 km from the station. Although these data are available for the period 1987-2012 (25 years), we confine the lightning information to the period 1987-2005 (18 years) only, since changes made to the lightning observation methodology in the years 2005-2006 raise concerns about the homogeneity of the whole observation record. Independent rainfall events that occurred during the warm half-year (April to September) are first identified from this database, with the requirement that the inter-arrival time between two subsequent events is at least 2 hours. Then, for each rainfall event, the key storm characteristics (total rainfall depth R, storm duration D, and peak 10-min intensity I) are computed, and the number of lightning strikes is assigned in the case the event was accompanied by lightning activity. We found that peak rainfall intensity I during events accompanied by lightning is significantly higher than during those events where no lightning was observed. There are smaller differences in the distributions of event durations and rainfall totals. On this basis, we define a threshold of peak intensity I* that differentiates between events with and without lightning with an acceptably small probability of misclassification. This allows us to identify intense summer events with convective character as those where I > I* regardless of their duration or total rainfall depth. In a final step, the spatial variability of I* across the analyzed stations in Switzerland is examined. The results suggest that threshold intensities I* are not constant in space and vary with a strong topographic and climatological signature.

Gaal, Ladislav; Molnar, Peter; Szolgay, Jan

2013-04-01

24

Application of the Aventech AIMMS20AQ airborne probe for turbulence measurements during the Convective Storm Initiation Project  

NASA Astrophysics Data System (ADS)

The Convective Storm Initiation Project (CSIP) took place during the summers of 2004 and 2005, centred on the research radar at Chilbolton, UK. Precursors to convective precipitation were studied, using a comprehensive and broad-based range of fieldwork and modelling. The principal aim of CSIP was the detection of the primary and secondary initiation of convective cells. The Universities Facility for Atmospheric Measurements (UFAM) Cessna 182 was used to map temperature and humidity fields over a broad area within and beyond the Chilbolton radar beam. Additionally, air motion was measured using a new turbulence probe, the AIMMS20AQ. The performance of the probe is critically appraised, based on calibrations, test flights and data flights flown during CSIP intensive operating periods. In general, the probe performed well, although some aspects require more careful data interpretation which we describe in detail.

Beswick, K. M.; Gallagher, M. W.; Webb, A. R.; Norton, E. G.; Perry, F.

2007-03-01

25

Application of the Aventech AIMMS20AQ airborne probe for turbulence measurements during the Convective Storm Initiation Project  

NASA Astrophysics Data System (ADS)

The Convective Storm Initiation Project (CSIP) took place during the summers of 2004 and 2005, centred on the research radar at Chilbolton, UK. Precursors to convective precipitation were studied, using a comprehensive and broad-based range of fieldwork and modelling. The principal aim of CSIP was the detection of the primary and secondary initiation of convective cells. The Universities Facility for Atmospheric Measurements (UFAM) Cessna 182 was used to map temperature and humidity fields over a broad area within and beyond the Chilbolton radar beam. Additionally, air motion was measured using a new turbulence probe, the AIMMS20AQ. The performance of the probe is critically appraised, based on calibrations, test flights and data flights flown during CSIP intensive operating periods. In general, the probe performed well, although some aspects require more careful data interpretation which we describe in detail.

Beswick, K. M.; Gallagher, M. W.; Webb, A. R.; Norton, E. G.; Perry, F.

2008-09-01

26

Tropical convective activities related to summer rainfall anomaly in China  

NASA Astrophysics Data System (ADS)

The paper presents the SVD-revealed relation of the tropical convection anomaly patterns to the summer rainfall counterparts of China, indicating that a) the ENSO-associated tropical con-vection anomaly is highly advantageous but the corresponding rainfall anomaly can only account for 10.3% of total variance, the rainfall anomaly related to tropical monsoon variation with the northern South China Sea as the center of convection abnormality for 18.8% and to the variation inside the tropical monsoon for 11.2%; b) the ENSO-related summer precipitation anomaly dis-plays a pattern of excessive rainfall in the south and deficit in the north, the anomaly relative to the tropical monsoon variation a pattern of more precipitation in the Yangtze River valleys and less in North, Northeast and South China, and that in relation to the variation within the tropical mon-soon a pattern of two rainbands, one in the Yangtze River valleys and the other in North China.

Guo, Pinwen; Tian, Hong; Liu, Xuanfei

2000-03-01

27

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

NASA Astrophysics Data System (ADS)

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.

Lee, Yun-Young; Lim, Gyu-Ho

2012-07-01

28

Severe convective storms and United States climate change in the latter half of the twentieth century  

Microsoft Academic Search

Severe local storms generated by atmospheric convection and enhanced by wind shear may increase in frequency within the United States, forced by increased surface temperature and other climate changes documented during the 20th Century. However, archives of thunderstorm and tornado events may not accurately represent the climate system, because storm reporting has been influenced by changing detection technologies, enhanced public

Diana Marie Derubertis

2003-01-01

29

THE SPATIAL DISTRIBUTION OF SEVERE CONVECTIVE STORMS AND AN ANALYSIS OF THEIR SECULAR CHANGES  

Microsoft Academic Search

Severe convective storms are responsible for billions of US dollars in damage each year around the world. They form an important part of the climate system by redistributing heat, moisture, and trace gases, as well as producing large quantities of precipitation. Reporting of severe convection varies from country to country, however, so that determining their distribution from the reports alone

Harold E. Brooks; Nikolai Dotzek

30

Growth Of The Summer Daytime Convective Boundary Layer At Anand  

NASA Astrophysics Data System (ADS)

The heights of the daytime convective boundary layer (CBL), computed by a one-dimensional model for a bare soil surface at a semi-arid station,Anand, during the dry and hot summer month of May 1997, are presented. As input, the model requires surface heat flux, friction velocity and air temperature as functions of time. Temperature data at the one-metre level from a tower and sonic anemometer data at 9.5 m collected during the period 13-17 May 1997 in the Land Surface Processes Experiment (LASPEX-97) are used to compute hourly values of surface heat flux, friction velocity and Obukhov length following the operational method suggested by Holtslag and Van Ulden [J. Climate Appl. Meteorol. 22,517-529 (1983)]. The model has been tested with different values for the potential temperature gradient ( ) above the inversion. The model-estimated CBL heights comparefavourably with observed heights obtained from radiosonde ascents.

Nagar, S. G.; Tyagi, Ajit; Seetaramayya, P.; et al.

31

Environments that Produce "Extreme" Convective Storm Behavior: Results from a Large Numerical Modeling Study  

NASA Astrophysics Data System (ADS)

The behavior of a convective storm is closely related to its ambient environment. In this paper, we explore the environments that produce "extreme" storm behaviors, namely, strong surface winds; copious amounts of precipitation (rain and hail); and strong low level rotation, related to tornadoes. The study focuses on a set of over 200 cloud-resolving numerical simulations, with the dominant storm in each simulation tracked and analyzed for up to 2 h. It is found that different environmental conditions are needed to produce different types of "extreme" behavior. For example, increased convective available potential energy (CAPE) typically causes the amount of hail produced to increase, but has relatively little effect on surface precipitation rates. The ambient precipitable water (PW) is found to have a greater impact on heavy rainfall than does CAPE. The storms with the strongest low level rotation exist in environments with low cloud bases and low, continental values of PW, however storms that produce large swaths of strong outflow winds at the surface occur in environments with deeper sub-cloud layers and enhanced PW. These and other relationships will be discussed. An understanding of these atmospheric conditions and how they relate to storm behavior will be critical for future study of long-term temporal trends in the distribution of convection-driven high impact weather.

Kirkpatrick, C.; McCaul, E. W., Jr.

2010-12-01

32

Variability of the North Atlantic summer storm track: mechanisms and impacts on European climate  

NASA Astrophysics Data System (ADS)

The summertime variability of the extratropical storm track over the Atlantic sector and its links to European climate have been analysed for the period 1948-2011 using observations and reanalyses. The main results are as follows. (1) The dominant mode of the summer storm track density variability is characterized by a meridional shift of the storm track between two distinct paths and is related to a bimodal distribution in the climatology for this region. It is also closely related to the Summer North Atlantic Oscillation (SNAO). (2) A southward shift is associated with a downstream extension of the storm track and a decrease in blocking frequency over the UK and northwestern Europe. (3) The southward shift is associated with enhanced precipitation over the UK and northwestern Europe and decreased precipitation over southern Europe (contrary to the behaviour in winter). (4) There are strong ocean-atmosphere interactions related to the dominant mode of storm track variability. The atmosphere forces the ocean through anomalous surface fluxes and Ekman currents, but there is also some evidence consistent with an ocean influence on the atmosphere, and that coupled ocean-atmosphere feedbacks might play a role. The ocean influence on the atmosphere may be particularly important on decadal timescales, related to the Atlantic Multidecadal Oscillation (AMO).

Dong, Buwen; Sutton, Rowan T.; Woollings, Tim; Hodges, Kevin

2013-09-01

33

Partitioning the distribution function of radar reflectivity in convective storms using maximum likelihood method  

NASA Astrophysics Data System (ADS)

A method to estimate the parameters of radar reflectivity distribution functions of convective storm systems is presented. To carry out this estimation, the probability density distribution of the radar reflectivity, P(Z), is computed using data collected on continental convective storm systems with the radar of Little Rock in central Arkansas. We show that P(Z) can be modeled as a mixture of Gaussian components, each of them corresponding to a type of precipitation. The EM (Expectation Maximization) algorithm is used to decompose P(Z) in these merged components. In the precipitation associated with intense continental convective storms, four main populations are considered: shallow precipitation, stratiform precipitation, convective precipitation, and hail. Each component is described by the fraction of area occupied inside P(Z) and by the Gaussian parameters, mean and variance. The retrieval of the mixed distribution by a linear combination of the Gaussian components gives a very satisfactory P(Z) fitting. It is shown that this method enables to follow the evolution with time of the various precipitation components of a convective system crossing the radar observed area.

Diop, Cheikh Abdoulahat; Sauvageot, Henri; Mesnard, Frédéric

2013-04-01

34

Case Studies on Convective Storms. Case Study 6. Dynamical-Microphysical Evolution of a Convective Storm, 25 July 1976.  

National Technical Information Service (NTIS)

On 25 July 1976 the life cycle of a small, moderate thunderstorm which occurred in northeast Colorado was observed extensively by participants in the National Hail Research Experiment. This storm is the subject of a series of four papers. Studies of the s...

J. E. Dye L. J. Miller B. E. Martner Z. Levin

1980-01-01

35

Lightning Location Relative to Storm Structure in Mesoscale Convective Systems  

NASA Astrophysics Data System (ADS)

Line normal composites of Dallas-Fort Worth Lightning Detection and Ranging (LDAR II) VHF radiation sources and WSR-88D reflectivity provide a unique perspective on lightning pathways and inferred charge structure within two leading-line, trailing-stratiform (LLTS) mesoscale convective systems (MCSs) during April and June of 2002. The overwhelming majority of VHF lightning sources occurred within the leading convective line in a vertical dipole pattern with upper and lower maxima centered at 9 - 9.5 km and 4.5 - 5 km AGL, respectively. A persistent, primary lightning pathway sloped rearward (by 40-50 km) and downward (by 4-5 km) from the upper VHF source maximum in the convective line, through the transition zone and into the stratiform region just above the radar bright band. A secondary and more transient lightning zone occurred 60-110 km rearward of the convective line in a spatially distinct layer (20-30 km long and 3 km deep) centered over the stratiform bright band from about 8.5 to 9.5 km AGL. Ongoing work includes a detailed comparison of individual sub-second LDAR II and NLDN detected stratiform-region ground flashes for the purpose of locating their origins. Preliminary results from these comparisons will be shown.

Carey, L. D.; McCormick, T. L.; Murphy, M. J.; Demetriades, N. W.

2003-12-01

36

Scientific Approaches for Very Short-Range Forecasting of Severe Convective Storms in the United States of America  

Microsoft Academic Search

SUMMARY A review of severe convective storm forecasting is given, with the emphasis on scientific approaches using mesoscale and storm-scale conceptual models. By concentrating on the ingredients for particular severe weather events, a focus is provided for the forecasting process. Such a focus is needed as diagnostic and prognostic products proliferate with the advent of new observing technology and powerful

CHARLES A. DOSWELL

37

Numerical modeling of severe convective storms occurring in the Carpathian Basin  

Microsoft Academic Search

Squall lines often cause serious damages due to the strong surface outflow, hail, or heavy precipitation in Hungary every summer. Squall lines in the Carpathian Basin can be classified into two main categories: pre-frontal squall-lines and frontal convective lines. In this paper, these two types of severe mesoscale phenomena are investigated using the high resolution numerical weather prediction model, the

Á. Horváth; I. Geresdi; P. Németh; K. Csirmaz; F. Dombai

2009-01-01

38

Impact of Thermal Perturbations from Urban Runoff During Summer Storms on Stream and Wetland Temperatures  

NASA Astrophysics Data System (ADS)

Runoff from heated parking lots during summer thunderstorms injects pulses of hot water into receiving water bodies. If the magnitude of such thermal perturbations is sufficient, aquatic organisms can be impacted. Such concerns are heightened because climate change will likely raise the temperature and reduce the magnitude of baseflow in aquatic systems. These pulses of elevated temperature also represent an opportunity to study how perturbations move through aquatic systems and how their migration is affected by physical parameters such as current velocity and channel form. While previous studies have determined that the impact of summer storm thermal pulses on stream temperatures can be significant, none have fully resolved the spatial extent and magnitude of these impacts in space or time in receiving streams nor compared impacts among different types of water bodies. Here we present preliminary temperature timeseries data collected using arrays of wireless temperature sensors in two example waterbodies (a stream with directional flow and a wetland with minimal current) immediately downstream of the outlet of storm sewers draining large nearby parking lots on the Virginia Tech campus in Blacksburg, VA. These data are useful to quantify the amplitude, duration, and evolution of thermal perturbations from individual storms and how these vary with current velocity, weather conditions, and other factors. We compare the magnitude of measured perturbations in the receiving water body to thermal tolerance data for aquatic species to evaluate expected biological impacts. We also outline future research planned on this topic.

Hester, E. T.

2009-12-01

39

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

SciTech Connect

A method is developed to initialize convective storm simulations with Doppler radar-derived fields. Input fields for initialization include velocity, rain water 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 [open quotes]shocks[close quotes] 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 initialized from observations taken at two different stages of storm development are shown and compared to observations taken at later times. A simulation initialized from one of the observation times showed good agreement with subsequent observations, though the simulated storm appeared to be evolving much faster than observed. Possible mechanisms for error growth are discussed.

Lin, Y.

1992-01-01

40

Inner magnetosphere convection and magnetotail structure of hot ions imaged by ENA during a HSS-driven storm  

NASA Astrophysics Data System (ADS)

The remotely measured increase in plasma sheet ion temperatures during high speed stream-driven storms is greater than that of ICME-driven storms. These hot ions are convected to the inner magnetosphere where they drive the ring current. On 22 July 2009, a high speed stream yielded a moderate (minimum Dst of -79 nT) storm, one of the largest that occurred during the extended solar minimum between January 2007 and September 2010. We present measurements obtained with an energetic neutral atom (ENA) imager of the TWINS mission during the main phase of the storm. Ion temperatures calculated from the ENA measurements show storm-time increase in ion temperature and a subsequent convection of hot ions into the inner magnetosphere. In the magnetotail, a region of hot ions near local midnight is observed that may be associated with substorm-related bursty bulk flows.

Keesee, A. M.; Elfritz, J. G.; McComas, D. J.; Scime, E. E.

2012-05-01

41

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

NASA Astrophysics Data System (ADS)

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 the three components of the wind. The second part of this study tests the radar data assimilation experiments through the evaluation of short, 1 hour forecasts initialized from the storm-scale analyses. It is found that the weak upward vertical velocity fields found in the storm-scale analyses did not preclude the development of deep convective storms with upward vertical motion representative of the observed storm types. In all radar data assimilation experiments a general eastward displacement of forecast storms relative to observed storms is observed. This displacement is hypothesized to be a result of storm re-development along cold pools during the first 10 to 20 minutes of the forecast. Furthermore, objective verification indicates that radar data assimilation compared to a case of no data assimilation generally improves the forecasts, and hybrid ensemble-3DVar assimilation yielded initial conditions which provided the best forecasts. A sensitivity was noted to the relative weights given to the static- and ensemble-based background error statistics. Experiments with 50% and 25% of the weight given to the static background error generally yielded the best forecast verification scores overall. It is noted that while these results demonstrate the effectiveness of hybrid ensemble-3DVar radar data assimilation at the convective-scale with the regional operational NWP infrastructure of the NWS, this is only an evaluation with a single case. Additional case studies are recommended before a more general conclusion may be obtained.

Carley, Jacob R.

42

Analysis and application of remote sensing data in a severe convective storm in Hunan, China  

NASA Astrophysics Data System (ADS)

A severe convective storm with thunder, shower and gust as well as hailstone in Hunan province, China on April 8, 2008 was investigated using the remote sensing data such as FY-2C satellite, Doppler radar and automatic surface weather network. The results show that 1. The previous warmer weather provided abundant unstable energy, and the vertical wind shear, thermo-dynamic factors are favorable for severe convection. 2. The mesoscale torrential rain clouds triggered by the tail of front-cyclone clouds caused the event. 3. The phenomenon that the thunder storm clouds were triggered by frontal cyclone clouds was revealed clearly by FY-2C satellite image. Cloud-Derived Wind image indicated the strong divergence at the high level. 4. The PPIs manifest as the isolated massive echoes, and the intense echo cores of storms is higher than 65dBz at the 3-6km altitude on reflectivity vertical section, the echo higher than 50dBz located at 9km high-level and the temperature is approximately - 30°C, the echo top height is higher than 12km. the PPIs at different levels show that the character of "three-body scattering spike" at 16:18, 16:36 and 16:54 respectively, namely typical character of hail echo. 5. For velocity, at the low and middle altitude, there were the cyclonic convergence and divergence at the high altitude.

Huang, Xiaoyu; Chen, Yuan; Liu, Hongwu; Cai, Ronghui; Shi, Ximing

2008-12-01

43

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

SciTech Connect

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.

Heimpel, Moritz [Department of Physics, University of Alberta, Edmonton, Alberta T6G 2J1 (Canada); Aurnou, Jonathan M., E-mail: mheimpel@ualberta.ca, E-mail: aurnou@ucla.edu [Department of Earth and Space Sciences, University of California, Los Angeles, CA (United States)

2012-02-10

44

The impact of climate change on severe convective storms over Europe  

NASA Astrophysics Data System (ADS)

The impact of climate change on severe convection over Europe is assessed by deriving convection-indices on the basis of 3-dimensional meteorological fields of two simulations of the regional climate model CLM: one simulation for the past (1979-2000) and one for the future (2079-2100). Verification of the method is attained by comparing the results with sounding-derived parameters on the basis of radiosondes, ERA-40 reanalysis and severe storm reports from the European Severe Weather Database (ESWD). Additionally, we will look at the relation between thunderstorm severity potential (TSP), Convective Inhibition (CIN), Convective Available Potential Energy (CAPE), deep-layer wind shear (DLS) and Lamb's circulation weather types (CWT) to investigate how the synoptic situation influences severe convection over continental Europe. If special circulation patterns change in the future, this might have an effect on the development of thunderstorms due to the modification in transport and advection of air mass. This study is part of the severe weather research project RegioExAKT (www.regioexakt.de).

Sander, J.; Dotzek, N.

2010-09-01

45

Severe convective storms initiated by intense wildfires: Numerical simulations of pyro-convection and pyro-tornadogenesis  

NASA Astrophysics Data System (ADS)

On the afternoon of 18 January 2003, wildfires swept through several outer suburbs of Canberra (Australia) producing, inter alia, a series of large pyro-cumulonimbus cells and at least one tornado. The results of a large-eddy simulation with a parameterized fire are reported here. The simulation, motivated by the Canberra wildfires and severe storms, captures the main characteristics of the observed pyro-cumulonimbi, including the formation of a tornado close to where one was observed. In addition, the model develops prominent horizontally oriented vortices on the western side of the fire in the direction of the low-level shear, and a series of horizontally oriented vortices on the upstream side of the convection column. The production of water by the fire is critical for the development of a pyro-cumulonimbus cell intense enough to reach the tropopause as observed and plays a significant role in the associated tornadogenesis.

Cunningham, Philip; Reeder, Michael J.

2009-06-01

46

Using a WRF simulation to examine regions where convection impacts the Asian summer monsoon anticyclone  

NASA Astrophysics Data System (ADS)

The Asian summer monsoon is a prominent feature of the global circulation that is associated with an upper-level anticyclone (ULAC) that stands out vividly in satellite observations of trace gases. The ULAC also is an important region of troposphere-to-stratosphere transport. We ran the Weather Research and Forecasting (WRF) model at convective-permitting scales (4 km grid spacing) between 10-20 August 2012 to understand the role of convection in transporting boundary layer air into the upper-level anticyclone. Such high-resolution modeling of the Asian ULAC previously has not been documented in the literature. Comparison of our WRF simulation with reanalysis and satellite observations showed that WRF simulated the atmosphere sufficiently well to be used to study convective transport into the ULAC. A back-trajectory analysis based on hourly WRF output showed that > 90% of convectively influenced parcels reaching the ULAC came from the Tibetan Plateau (TP) and the southern slope (SS) of the Himalayas. A distinct diurnal cycle is seen in the convective trajectories, with their greatest impact occurring between 1600-2300 local solar time. This finding highlights the role of "everyday" diurnal convection in transporting boundary layer air into the ULAC. WRF output at 15 min intervals was produced for 16 August to examine the convection in greater detail. This high-temporal output revealed that the weakest convection in the study area occurred over the TP. However, because the TP is at 3000-5000 m a.m.s.l., its convection does not have to be as strong to reach the ULAC as in lower altitude regions. In addition, because the TP's elevated heat source is a major cause of the ULAC, we propose that convection over the TP and the neighboring SS is ideally situated geographically to impact the ULAC. The vertical mass flux of water vapor into the ULAC also was calculated. Results show that the TP and SS regions dominate other Asian regions in transporting moisture vertically into the ULAC. Because convection reaching the ULAC is more widespread over the TP than nearby, we propose that the abundant convection partially explains the TP's dominant water vapor fluxes. In addition, greater outgoing longwave radiation reaches the upper levels of the TP due to its elevated terrain. This creates a warmer ambient upper level environment, allowing parcels with greater saturation mixing ratios to enter the ULAC. Lakes in the Tibetan Plateau are shown to provide favorable conditions for deep convection during the night.

Heath, N. K.; Fuelberg, H. E.

2013-09-01

47

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)

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 gust fronts producing a relatively steady storm system and greater surface precipitation rates than in the clean case, until such time as the storm systems re-develop in the clean case. The details of the aerosol indirect effects on the microphysical and precipitation characteristics of these convective storms, their resultant impacts on the cold pool characteristics and dynamical forcing of convection, and the subsequent influence on surface precipitation will be presented.

van den Heever, S. C.

2008-12-01

48

A two year (2008-2009) analysis of severe convective storms in the Mediterranean basin as observed by satellite imagery  

Microsoft Academic Search

The increasing damages caused by natural disasters, a great part of them being direct or indirect effects of severe convective storms (SCS), seem to suggest that extreme events occur with greater frequency, also as a consequence of climate changes. A better comprehension of the genesis and evolution of SCS is then necessary to clarify if and what is changing in

B. Gozzini; S. Melani; F. Pasi; A. Ortolani

2010-01-01

49

Impacts of cumulus convective parameterization schemes on summer monsoon precipitation simulation over China  

NASA Astrophysics Data System (ADS)

By using the Betts-Miller-Janji?, Grell-Devenyi, and Kain-Fritsch cumulus convective parameterization schemes in theWeather Research and Forecasting (WRF) model, long time simulations from 2000 to 2009 are conducted to investigate the impacts of different cumulus convective parameterization schemes on summer monsoon precipitation simulation over China. The results show that all the schemes have the capability to reasonably reproduce the spatial and temporal distributions of summer monsoon precipitation and the corresponding background circulation. The observed north-south shift of monsoon rain belt is also well simulated by the three schemes. Detailed comparison indicates that the Grell-Devenyi scheme gives a better performance than the others. Deficiency in simulated water vapor transport is one possible reason for the precipitation simulation bias.

Yu, Entao; Wang, Huijun; Gao, Yongqi; Sun, Jianqi

2011-10-01

50

Summer season land cover-convective cloud associations for the Midwest U.S. ``Corn Belt''  

Microsoft Academic Search

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

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

2001-01-01

51

UV Dosage Levels in Summer: Increased Risk of Ozone Loss from Convectively Injected Water Vapor  

NASA Astrophysics Data System (ADS)

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 CO2 and CH4 to the atmosphere, increased risk of ozone loss and associated increases in ultraviolet dosage would follow.

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

2012-08-01

52

Zonal propagation of kinetic energy and convection in the South China Sea and Indian monsoon regions in boreal summer  

Microsoft Academic Search

Zonal propagation of kinetic energy (KE) and convection in the South China Sea (SCS) and Indian summer monsoon areas are examined\\u000a in present study. Results suggest that the SCS and Indian summer monsoon prevailed regions (5–15°N) are dominated by the southwesterly\\u000a wind, however, the disturbances of KE at 850 hPa and convection are observed mainly coming from the western Pacific

Longxun Chen; Hui Gao; Jinhai He; Shiyan Tao; Zuhui Jin

2004-01-01

53

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

NASA Astrophysics Data System (ADS)

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 show larger values of convective inhibition (CIN) in the morning. In comparison to the standard simulation, the initiation of clouds and convection is delayed but occurs more sudden and intense than in the moister simulations, despite a reduction of mean precipitation amounts. We discuss this result in relation to the climate change scenarios mentioned above.

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

2010-05-01

54

Dynamical and Microphysical Retrieval from Doppler Radar Observations Using a Cloud Model and Its Adjoint. Part II: Retrieval Experiments of an Observed Florida Convective Storm  

Microsoft Academic Search

The variational Doppler radar analysis system developed in part I of this study is tested on a Florida airmass storm observed during the Convection and Precipitation\\/ Electrification Experiment. The 3D wind, temperature, and microphysical structure of this storm are obtained by minimizing the difference between the radar-observed radial velocities and rainwater mixing ratios (derived from reflectivity) and their model predictions.

Juanzhen Sun; N. Andrew Crook

1998-01-01

55

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

Microsoft Academic Search

Northwest flow severe weather outbreaks (NWF outbreaks) describe a type of summer convective storm that occurs in areas of\\u000a mid-level NWF in the central United States. Convective storms associated with NWF outbreaks often travel a long distance systematically\\u000a along a northwest-southeast oriented track across the northern plains. Previous studies have observed that these migrating\\u000a convective storms are frequently coupled with

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

2011-01-01

56

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

NASA Astrophysics Data System (ADS)

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).

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

57

Sensitivity of the simulated East Asian summer monsoon climatology to four convective parameterization schemes  

NASA Astrophysics Data System (ADS)

This study attempts to clarify the effects of parameterized convection on a simulated East Asian summer monsoon climatology from 1997 to 2006 within a regional climate model (RCM) framework. Four different convective parameterized schemes (CPSs) were chosen in the National Centers for the Environmental Prediction regional spectral model, the Simplified Arakawa-Schubert (SAS), Relaxed Arakawa-Schubert (RAS), NCAR Community Climate Model version 3 (CCM), and new Kain-Fritsch (KF2) schemes. On the whole, there is no single scheme that outperforms the other in all aspects of the simulated climatology. The results show that the SAS and KF2 schemes are capable of reproducing the 10-year June-July-August climatology with a certain wet bias over land and dry bias over the oceans. The SAS scheme is capable of resolving the interannual variations of the monsoon precipitation, and the KF2 is able to capture the intraseasonal variation. The RAS scheme significantly reduces precipitation over land compared to other schemes, but interannual variabilities are reasonably reproduced. On the contrary, the CCM scheme significantly overestimates the precipitation over land as well as ocean. Discernable differences among four CPSs are found in the distribution of the spatial spectrum, in which the KF2 scheme is the most effective in adding regional details to an external large-scale forcing. The feasibility of a physics ensemble using different convection schemes and the impacts of domain size are also discussed.

Kang, Hyun-Suk; Hong, Song-You

2008-08-01

58

Numerical simulations of the July 10, 1996, Stratospheric-Tropospheric Experiment: Radiation, Aerosols, and Ozone (STERAO)-deep convection experiment storm: Redistribution of soluble tracers  

Microsoft Academic Search

By using a three-dimensional convective cloud model to simulate the July 10, 1996, Stratospheric-Tropospheric Experiment: Radiation, Aerosols, and Ozone-Deep Convection experiment storm, we investigate the fate of tracers of varying solubilities in midlatitude convection. The tracer distribution resulting from the interactions of the soluble tracers with the cloud hydrometeors is illustrated for two cases. The first case assumes that the

M. C. Barth; A. L. Stuart; W. C. Skamarock

2001-01-01

59

Numerical simulations of the July 10, 1996, Stratospheric-Tropospheric Experiment: Radiation, Aerosols, and Ozone (STERAO)Deep Convection experiment storm: Redistribution of soluble tracers  

Microsoft Academic Search

By using a three-dimensional convective cloud model to simulate the July 10, 1996, Stratospheric-Troposphedc Experiment: Radiation, Aerosols, and Ozone-Deep Convection experiment storm, we investigate the fate of tracers of varying solubilities in midlatitude convection. The tracer distribution resulting from the interactions of the soluble tracers with the cloud hydrometeors is illustrated for two cases. The first case assumes that the

M. C. Barth; A. L. Stuart; W. C. Skamarock

2001-01-01

60

Performance assessment of three convective parameterization schemes in WRF for downscaling summer rainfall over South Africa  

NASA Astrophysics Data System (ADS)

Austral summer rainfall over the period 1991/1992 to 2010/2011 was dynamically downscaled by the weather research and forecasting (WRF) model at 9 km resolution for South Africa. Lateral boundary conditions for WRF were provided from the European Centre for medium-range weather (ECMWF) reanalysis (ERA) interim data. The model biases for the rainfall were evaluated over the South Africa as a whole and its nine provinces separately by employing three different convective parameterization schemes, namely the (1) Kain-Fritsch (KF), (2) Betts-Miller-Janjic (BMJ) and (3) Grell-Devenyi ensemble (GDE) schemes. All three schemes have generated positive rainfall biases over South Africa, with the KF scheme producing the largest biases and mean absolute errors. Only the BMJ scheme could reproduce the intensity of rainfall anomalies, and also exhibited the highest correlation with observed interannual summer rainfall variability. In the KF scheme, a significantly high amount of moisture was transported from the tropics into South Africa. The vertical thermodynamic profiles show that the KF scheme has caused low level moisture convergence, due to the highly unstable atmosphere, and hence contributed to the widespread positive biases of rainfall. The negative bias in moisture, along with a stable atmosphere and negative biases of vertical velocity simulated by the GDE scheme resulted in negative rainfall biases, especially over the Limpopo Province. In terms of rain rate, the KF scheme generated the lowest number of low rain rates and the maximum number of moderate to high rain rates associated with more convective unstable environment. KF and GDE schemes overestimated the convective rain and underestimated the stratiform rain. However, the simulated convective and stratiform rain with BMJ scheme is in more agreement with the observations. This study also documents the performance of regional model in downscaling the large scale climate mode such as El Niño Southern Oscillation (ENSO) and subtropical dipole modes. The correlations between the simulated area averaged rainfalls over South Africa and Nino3.4 index were -0.66, -0.69 and -0.49 with KF, BMJ and GDE scheme respectively as compared to the observed correlation of -0.57. The model could reproduce the observed ENSO-South Africa rainfall relationship and could successfully simulate three wet (dry) years that are associated with La Niña (El Niño) and the BMJ scheme is closest to the observed variability. Also, the model showed good skill in simulating the excess rainfall over South Africa that is associated with positive subtropical Indian Ocean Dipole for the DJF season 2005/2006.

Ratna, Satyaban B.; Ratnam, J. V.; Behera, S. K.; Rautenbach, C. J. deW.; Ndarana, T.; Takahashi, K.; Yamagata, T.

2013-08-01

61

Simultaneous observation of an above-anvil ice plume and plume-shaped BTD anomaly atop a convective storm  

NASA Astrophysics Data System (ADS)

This study focuses on a convective storm that occurred late afternoon on 06 July 2010 above the Adriatic coast of the North Italy. A well-defined cold-U signature and a distinct above-anvil ice plume were present within the storm cloud top in Meteosat Spinning Enhanced Visible and InfraRed Imager (SEVIRI) infrared (IR) band imagery. The most interesting aspect of this case was the anomalous brightness temperature difference (BTD) between the 6.2 ?m water vapor absorption (WV6.2) and the 10.8 ?m infrared window (IR10.8) bands depicted with SEVIRI 5-minute rapid scan data. The BTD is usually positive above cold storm cloud tops. The positive BTD can be either closely correlated to the IR10.8 brightness temperature or exhibit various local "BTD anomalies". While other recent studies focus on statistical characteristics of the positive BTD, we focus on a distinct BTD anomaly which developed at the top of the aforementioned storm. This case is unique because of the simultaneous occurrence of the BTD anomaly and a nearby ice plume. In this case the BTD anomaly resembles a distinct plume-like feature for a short period of time but had a rather irregular oval outline for most of its existence. The significance of the co-existence of both features is discussed as well as details of the BTD evolution.

Putsay, M.; Simon, A.; Setvák, M.; Szenyán, I.; Kerkmann, J.

2013-04-01

62

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

USGS Publications Warehouse

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).

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

2011-01-01

63

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

USGS Publications Warehouse

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.

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

2011-01-01

64

Convectively injected water vapor in the North American summer lowermost stratosphere  

NASA Astrophysics Data System (ADS)

Anderson et al. (2012) (A2012) report in situ observations of convectively injected water vapor (H2O) in the North American (NA) summer lowermost stratosphere (LMS), occasionally exceeding 12ppmv. They contend that, in such cold/wet conditions, heterogeneous chemistry on binary water?sulfate aerosols can activate chlorine, leading to catalytic ozone destruction. Aura Microwave Limb Sounder 100 hPa and 82.5 hPa H2O measurements show that, indeed, the NA LMS is unusually wet, both in mean values and in outliers reaching 18ppmv. Using A2012's threshold, 4% (0.03%) of 100 hPa (82.5 hPa) NA July-August observations are cold/wet enough for activation. Cold parcels, whether wet or dry, typically have much less HCl to activate and O3to destroy than A2012's initial conditions. Slightly lower concentrations of HCl and O3 in cold/wet parcels are attributable, at least in part, to dilution by tropospheric air. Alarming reductions in NA summer column O3suggested by A2012 are not seen in the current climate.

Schwartz, Michael J.; Read, William G.; Santee, Michelle L.; Livesey, Nathaniel J.; Froidevaux, Lucien; Lambert, Alyn; Manney, Gloria L.

2013-05-01

65

The importance of the representation of deep convection for modeled dust-generating winds over West Africa during summer  

NASA Astrophysics Data System (ADS)

West Africa is the world's largest source of airborne mineral dust, which affects weather, climate, and biogeochemical processes. We use continental-scale ten-day simulations from the UK Met Office Unified Model to study the effects of the representation of deep convection on modeled dust-generating winds in summertime West Africa. To isolate the role of meteorology from the land surface we use a new diagnostic parameter “uplift potential”, which represents the dependency of dust uplift on wind-speed for an idealized land surface. Runs permitting explicit convection suggest that cold pool outflows from moist convection (so called “haboob” dust storms) potentially generate on the order of half the dust uplift. Simulations with parameterized convection show substantially less haboob uplift, but compensating increased uplift from low-level jets associated with a stronger Saharan heat low (SHL). This leads to reduced dust emission on convectively active days, in the afternoon and evening hours, and in the Sahel. The common practice of tuning coarse-resolution dust models cannot resolve these problems. A realistic representation of the dust cycle, as well as of the SHL, requires targeted efforts to develop computationally inexpensive ways to incorporate the effects of cold-pool outflows from deep convection.

Marsham, John H.; Knippertz, Peter; Dixon, Nick S.; Parker, Douglas J.; Lister, Grenville M. S.

2011-08-01

66

Midweek increase in U.S. summer rain and storm heights suggests air pollution invigorates rainstorms  

Microsoft Academic Search

Tropical Rainfall Measuring Mission (TRMM) satellite estimates of summertime rainfall over the southeast U.S. are found on average to be significantly higher during the middle of the work week than on weekends, attributable to a midweek intensification of afternoon storms and an increase in area with detectable rain. TRMM radar data show a significant midweek increase in the echo-top heights

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

2008-01-01

67

Summer-winter hemisphere asymmetry of the preliminary reverse impulse of geomagnetic storm sudden commencements at midlatitudes  

NASA Astrophysics Data System (ADS)

We present event-specific observational evidence for the prevalence of a summer-winter hemisphere asymmetry of the preliminary reverse impulse (PRI) of geomagnetic storm sudden commencements (SSCs) at midlatitudes of the local afternoon sector. The evidence is culled from the archived 10-s resolution data of midlatitude stations (geomagnetic latitude 23-46°) of the MM 210 magnetometer network. The hemisphere asymmetry is characterized by a larger peak amplitude of PRI in the summer hemisphere than in the winter hemisphere, and this feature is more prominently seen in the December solstice compared to the June solstice. In the December solstice SSC event, the amplitude of the preliminary reverse impulse, PRI (4.8 nT) at BRV (geomagnetic latitude 36.6°S) in the summer hemisphere is larger by a factor of 6 compared to that at MSR (geomagnetic latitude 37.6°N) in the winter hemisphere. The asymmetry is also apparent at lower latitudes: while the PRI assumed an amplitude of 3.7 nT at LEM (geomagnetic latitude 34.1°S), it is barely discernible at ONW (geomagnetic latitude 31.6°N) in the winter hemisphere. In the June solstice event, the PRI amplitude at RIK (geomagnetic latitude 34.7°N) in the summer hemisphere is higher by a factor of 3.44 compared to that at LEM (geomagnetic latitude 34.1°S) in the winter hemisphere. A similar behavior is also apparent in the equinox event though the hemisphere asymmetry of the preliminary reverse impulse (PRI) here is of moderate strength. In all the SSC events studied, the main impulse (MI) amplitude also exhibited the well-known summer-winter asymmetry, but the hemisphere asymmetry is more prominent with the preliminary reverse impulse (PRI) than with the main impulse (MI). Physical processes that could possibly account for the hemisphere asymmetry evidenced of the afternoon PRI at midlatitudes are discussed.

Sastri, J. H.; Yumoto, K.; Rao, J. V. S. V.; Ikeda, A.

2008-05-01

68

The vertical profile of radar reflectivity of convective cells: A strong indicator of storm intensity and lightning probability?  

SciTech Connect

Reflectivity data from Doppler radars are used to construct vertical profiles of radar reflectivity (VPRR) of convective cells in mesoscale convective systems (MCSs) in three different environmental regimes. The National Center for Atmospheric Research CP-3 and CP-4 radars are used to calculate median VPRR for MCSs in the Oklahoma-Kansas Preliminary Regional Experiment for STORM-Central in 1985. The National Oceanic and Atmospheric Administration-Tropical Ocean Global Atmosphere radar in Darwin, Australia, is used to calculate VPRR for MCSs observed both in oceanic, monsoon regimes and in continental, break period regimes during the wet seasons of 1987/88 and 1988/89. The midlatitude and tropical continental VPRRs both exhibit maximum reflectivity somewhat above the surface and have a gradual decrease in reflectivity with height above the freezing level. In sharp contrast, the tropical oceanic profile has a maximum reflectivity at the lowest level and a very rapid decrease in reflectivity with height beginning just above the freezing level. The tropical oceanic profile in the Darwin area is almost the same shape as that for two other tropical oceanic regimes, leading to the conclustion that it is characteristic. The absolute values of reflectivity in the 0 to 20 C range are compared with values in the literature thought to represent a threshold for rapid storm electrification leading to lightning, about 40 dBZ at -10 C. The large negative vertical gradient of reflectivity in this temperature range for oceanic storms is hypothesized to be a direct result of the characteristically weaker vertical velocities observed in MCSs over tropical oceans..

Zipser, E.J.; Lutz, K.R. [Texas A& M Univ., College Station, TX (United States)

1994-08-01

69

A two year (2008-2009) analysis of severe convective storms in the Mediterranean basin as observed by satellite imagery  

NASA Astrophysics Data System (ADS)

The increasing damages caused by natural disasters, a great part of them being direct or indirect effects of severe convective storms (SCS), seem to suggest that extreme events occur with greater frequency, also as a consequence of climate changes. A better comprehension of the genesis and evolution of SCS is then necessary to clarify if and what is changing in these extreme events. The major reason to go through the mechanisms driving such events is given by the growing need to have timely and precise predictions of severe weather events, especially in areas that show to be more and more sensitive to their occurrence. When dealing with severe weather events, either from a researcher or an operational point of view, it is necessary to know precisely the conditions under which these events take place to upgrade conceptual models or theories, and consequently to improve the quality of forecasts as well as to establish effective warning decision procedures. The Mediterranean basin is, in general terms, a sea of small areal extent, characterised by the presence of several islands; thus, a severe convection phenomenon originating over the sea, that lasts several hours, is very likely to make landfall during its lifetime. On the other hand, these storms are quasi-stationary or very slow moving so that, when convection happens close to the shoreline, it is normally very dangerous and in many cases can cause very severe weather, with flash floods or tornadoes. An example of these extreme events is one of the case study analysed in this work, regarding the flash flood occurred in Giampileri (Sicily, Italy) the evening of 1st October 2009, where 18 people died, other 79 injured and the historical centre of the village seriously damaged. Severe weather systems and strong convection occurring in the Mediterranean basin have been investigated for two years (2008-2009) using geostationary (MSG) and polar orbiting (AVHRR) satellite data, supported by ECMWF analyses and severe weather reports. The spatial and seasonal variability of storm occurrence have been also analysed, as well as the most favourable synoptic conditions for their formation. The analysis shows the existence of preferential areas of genesis of these extreme events, mainly located in the central Mediterranean (i.e., Ionic and Tyrrhenian seas), where the storms develop and grow preferentially in fall. The synoptic features, identified as precursors of severe convective events genesis, show how the totality of the identified cases occur in mid-troposphere (500 hPa) troughs or cut-off circulation within southerly flow, with values of deep level shear of at least 15 m s-1 and high ?e (850 hPa) values. Among all the detected cases of severe convection, two selected cases of enhanced-V features are presented in detail, either for the different synoptic environments in which they are embedded, and for being long-lived or severe in terms of heavy rainfall and damages they produced at the ground. In a long-term perspective, this preliminary study aims to make a climatological database of severe weather events occurring in the Mediterranean sea which may critically impact on the Italian peninsula and potentially affect population, in order to develop an objective procedure which can support regional meteorological services in forecasting extreme events, their development and impact, for taking proper early decisions.

Gozzini, B.; Melani, S.; Pasi, F.; Ortolani, A.

2010-09-01

70

Improve the simulation of western North Pacific summer monsoon in RegCM3 by suppressing convection  

NASA Astrophysics Data System (ADS)

Regional climate models, such as RegCM3, generally show large biases in the simulation of western North Pacific (WNP) summer monsoon (WNPSM). In this study, the authors improved the simulation of WNPSM by applying the convection suppression criterion based on the averaged relative humidity from cloud base to cloud top. The simulated rainfall and monsoon circulation are significantly improved. The suppressed convective heating associated with the decrease in convective rainfall simulates a low-level anomalous anticyclone to its north. The anomalous anticyclone reduces the intensity of low-level southwesterly flow and the wind speed at 10 m. The reduction in wind speed at 10 m decreases the evaporation at sea surface. The less supply of water vapor from underlying ocean in turn favors less convective rainfall. The overestimation of simulated convective percentages and the cold bias of 2 m air temperature are also reduced. The different effects of convection suppression criterion in stand-alone RegCM3 and corresponding regional air-sea coupled model are also discussed.

Zou, Liwei; Zhou, Tianjun

2013-07-01

71

A Life History of an Intense Mesoscale Convective Storm in Oklahoma  

Microsoft Academic Search

A simple automated objective analysis scheme is developed to analyze upper air sounding data from the National Severe Storm Laboratory mesonetwork. This scheme uses a combination of Cressman' successive correction technique and cubic spline curve fitting.This scheme is applied to a squall line case that occurred on 8 June 1966 along the confluent line where and air from the desert

Yoshmitsu Ogura; Yi-Leng Chen

1977-01-01

72

Infrasound From Convective Storms: An Experimental Test of Electrical Source Mechanisms  

Microsoft Academic Search

paper reports the results of such a test. We find that the spatial and temporal correlation between the two kinds of emissions is much lower than we would expect if the two were causally related; therefore the source of severe storm infrasound is probably not electrical.

William H. Beasley; T. M. Georges; Michael W. Evans

1976-01-01

73

The role of convective equilibrium in the characterization and the predictability of severe storms in Italy  

NASA Astrophysics Data System (ADS)

The predictability of severe rainfall by means of high resolution numerical weather models is a long standing issue for meteorological community. This study intends to provide an objective system to single out heavy rainfall events and to classify them on the basis of duration, spatial extent and large/small-scale triggering. Italy has built up one of the densest hourly-reporting raingauge networks and its data are presently archived and available. The first part of the work was devoted to developing a procedure to identify extreme precipitation events and its application to the full set of raingauges (about 1700 stations) all over Italy for the period 2006-2008 (Molini et al., 2009). This method allowed for the classification of about 100 events, either as long-lived (if lasting more than 12 hours) and spatially distributed (more than 50x50 km2), or brief and localized, (having a shorter duration and a minor spatial extent). For each of aforementioned events, the observed rainfall distributions have been compared with COSMO-I7 forecasts using spectral and statistical analyses. The second part of the work examines the hypothesis that the differences in predictability between these two classes of event are associated with different mechanisms of control of the precipitation by dynamical processes in the atmosphere. In particular, we ask whether the forcing of convection is sufficiently homogeneous and slowly varying that the convection can be considered to be in equilibrium or, otherwise, the outbreak of convection is more abrupt and small-scale driven (Done et al., 2006). Using ECMWF analysis (ERA-Interim) of convective available potential energy (CAPE), and precipitation analysed from the rain gauge network, we calculate the magnitude and time evolution of the timescale of convective adjustment for the severe events singled out in the first part. As expected, the events with higher predictability are mainly associated with short convective adjustment timescales which indicate equilibrium convection, while the short-lived, less predictable events have long convective timescales.

Molini, L.; Parodi, A.; Rebora, N.; Craig, G. C.

2009-09-01

74

The limited role of localized convective storms in runoff production in the western Negev Desert  

Microsoft Academic Search

High-scale floods in the Negev Desert are usually linked to rains originating from the Red Sea Trough (RST), characterized by high-intensity rainspells. While the effect of the RST storms was assessed in the southern, central and eastern parts of the Negev, almost no information exists as to their possible impact in the western parts of the Negev.Rain characteristics and its

G. J Kidron; K Pick

2000-01-01

75

High-latitude ionosphere convection and Birkeland current response for the 15 May 2005 magnetic storm recovery phase  

NASA Astrophysics Data System (ADS)

The high-latitude response of sunward E × B flow and Birkeland field-aligned currents (FAC) is analyzed for the 15 May 2005 magnetic cloud that generated a great magnetic storm (SYM-H = -305 nT at 0820 UT). The interplanetary magnetic field (IMF) clock angle, ? = arctan(By/Bz), gradually rotated from 65° to -80° during the 10-h long northward IMF period and the recovery of this storm. DMSP observations confirm a dawnward migration of a Northern Hemisphere sunward E × B flow channel (FC) between a downward and upward FAC pair. This FAC system developed during southward IMF (? = 109°) at the poleward edge of the duskside auroral oval as part of a four-sheet FAC system 23 min before the IMF became northward. TIMED/GUVI observations show that the dawnward migration of the upward FAC coincides with a drifting transpolar auroral arc (TPA). IMAGE/WIC did not observe a TPA in the southern (winter) hemisphere. DMSP and Iridium observations are in good agreement with MHD simulation predictions of a northward IMF reorientation of high-latitude FACs. The northern FC migration was likely due to summer hemisphere conductances, a strong average IMF Bx = -35 nT and the sunward dipole tilt angle that favor a northern high-latitude reconnection mechanism for a well-organized sunward FC and FAC system migration. The storm recovery rate appeared to be related with the region 2 FAC. A fast 11.4 nT/h rate was observed for a weak or nonexistent region 2 system during the high-latitude FAC redistribution. The SYM-H recovery slowed significantly to 0.9 nT/h following the 1800 UT region 2 system recovery.

Eriksson, S.; Hairston, M. R.; Rich, F. J.; Korth, H.; Zhang, Y.; Anderson, B. J.

2008-03-01

76

Ground-based observations during the period between two strong November 2004 storms attributed to steady magnetospheric convection  

NASA Astrophysics Data System (ADS)

Strong geomagnetic storms are of great scientific interest because they drive the magnetosphere to an extreme state and result in nontypical magnetosphere-ionosphere coupling. The present study examines the ground-based signatures of the magnetosphere-ionosphere disturbances during the recovery phase of the very intense storm on 7-8 November 2004. The recovery phase took place under steady and slightly negative (˜-5 nT) values of the IMF Bz. We compare this event with previously documented storm recovery phases occurring under positive IMF Bz and accompanied by morning Pc5 geomagnetic pulsations. During the period studied in this article the strongest pulsation activity was recorded in the evening and midnight sectors of the Earth. We analyze observations from the Scandinavian multipoint ground-based instrumentation: (1) geomagnetic variations and pulsations, (2) auroras in visual wavelengths, and (3) energetic particle precipitation (riometer data). We show that several enhancements in electrojet, auroral, and energetic precipitation activity were recorded at auroral latitudes. The activations lasted 0.5-2 hours, and the associated negative magnetic field deviations were often more than 1000 nT. Only one of these activations shows typical substorm behavior (poleward expansion and geostationary particle injection). We demonstrate remarkably good correlation between the magnetic variations and cosmic noise absorption variations (in pulsations and slower variations) as well as between the optical auroras and cosmic noise absorption (Imaging Riometer for Ionospheric Studies riometer system) both in time and in space. Thus the auroral precipitation revealed a very coherent behavior over a wide energy range (˜1-40 keV) during the analyzed period. The images acquired by the network of MIRACLE all-sky cameras show that the auroral distribution exhibited double oval configuration during our event. Double oval is often observed during so-called Steady Magnetospheric Convection (SMC) episodes. Furthermore, multiple auroral streamers were recorded, implying probable occurrence of bursty bulk flows (BBFs) in the magnetotail. The absence of recurrent geostationary injections, the wide oval configuration, and BBF signatures lead us to suggest that the intermediate period between the two November 2004 superstorms can be attributed to a SMC period. Mapping the motion of ionospheric signatures to the magnetotail with the Tsyganenko 96 models suggests BBF earthward speeds of ˜600-800 km/s. We suppose that the main drivers for the above described recurrent and intensive ionospheric phenomena are energy input from the solar wind due to slightly negative values of IMF Bz as well as huge energy storage in the magnetotail due to the previous storm main phase.

Manninen, J.; Kleimenova, N. G.; Kozyreva, O. V.; Ranta, A.; Kauristie, K.; MäKinen, S.; Kornilova, T. A.

2008-03-01

77

Study of a convective storm series and of precipitated hail in south Argentina  

NASA Astrophysics Data System (ADS)

A study of the period 10-19 February 1990, when frequent hailstorms occurred in the High Valley of Rio Negro and Neuquén (40°S, 65-70°W), is performed. The synoptic situation responsible for the observed convective events is characterized by the presence of a blocking high on the Atlantic Ocean (40°S, 50°W) that results in prevailing easterly winds and consequent high surface humidity. Information about precipitated hail is obtained from a network of 110 hailpad stations and from the crystal structure of hailstone samples. It is shown that, though kinetic energies up to about 1000 Jm -2 were evaluated in some stations, rather small hail with diameter D ˜ 10 mm prevailed in the hail size distributions while particles with 25-30 mm diameter were relatively few. Crop damage estimations are related to kinetic energy and stone number density on the ground, derived from hailpad analysis. It is found that, due to the type of fruit cultivation, an energy of about 100 Jm -2 was enough to determine total crop destruction. A one dimensional time independent (1DTI) model is applied to morning radiosonde data to stimulate cloud development. It is shown that the atmosphere instability, though moderate, was favorable to convection on most days of the period. For days when hail falls occurred, an accretion growth model is used to simulate the vertical motion and the development of ice particles growing in the environmental conditions characterizing the modeled cloud. It is found, that the size attained by particles displaying an up-and-down trajectory in the model could be favorably compared with the largest sizes registered on the ground and that most simulated hailstone growth occurred at rather low cloud levels, in agreement with the observed hailstone structure. Relations between the hailstone size and the simulated updraft intensity at middle levels, usually located below the updraft maximum, are suggested. The importance of the ice phase on the cloud depth and on the updraft profile shape is discussed.

Levi, Laura; Lubart, Luisa; Lässig, Jorge

78

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)

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-cell vortices. With the aid of the CRCM ring current simulation, we show that the R2 FAC develops immediately after the growth of the R1 FAC, and produces a reversed electric potential at mid latitude when the R1 FAC decreases its intensity. Thus, the reversed convection on the SuperDARN convection map must be caused by an electric potential associated with the R2 FAC. As a conclusion, both the convection and overshielding electric fields appear at mid-equatorial latitudes, and the overshielding electric field could become predominant irrespective of the period of the disturbances, when the R1 FAC decreases its intensity. This scenario well explains both the continuous penetration over several hours during storm main phase and the overshielding at the beginning of storm recovery phase.

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

2008-12-01

79

Ionospheric convection observations following the solar flare of 20 January 2005 and during the geomagnetic storm of 21 January 2005  

NASA Astrophysics Data System (ADS)

The MINIS balloon campaign was successfully conducted in January 2005 to investigate relativistic electron loss mechanisms. The MINIS campaign provided multi-point measurements of electron precipitation up to MeV energies, including simultaneous measurements at different longitudes and hemispheres. Two balloons, each carrying an X-ray spectrometer for measuring the bremsstrahlung produced as electrons precipitate into the atmosphere, were launched from Churchill, Manitoba. Four balloons, each carrying an X-ray spectrometer, and a 3-axis electric field instrument providing DC electric field and VLF measurements in 3 frequency bands, were launched from the South African Antarctic Station (SANAE IV). An X 7.1 solar flare occurred at 0636 UT on 20 January 2005. A CME from this flare arrived at the Earth 34 hours later. An SSC began at ~1650 UT followed by a geomagnetic storm with a Dst perturbation of ~-100nT. The AE index shows that the 20 January flare was followed first by 6 hours of deep quiet and then 28 hours of moderate activity. The balloon data contain evidence for two interesting geoelectric responses to the flare. The response of the tropospheric global circuit is discussed in a companion paper. There was an abrupt reduction of the horizontal electric field to a value near zero. Either the column resistance between the balloon and the ground fell to a value near zero, or the increased load from the ionosphere shorted out the cross-polar-cap potential. The arrival of the CME initiated an interval of very strong relativistic electron precipitation. The second and third Southern payloads and the first Northern payload made observations in both hemispheres of several extensive relativistic electron precipitation events that occurred from 1700 to 2000 UT on 21 January 2005. Each x-ray burst was preceded by a strong pulse of ionospheric convection. These flow bursts were directed poleward and sunward transport. The detailed comparison of data from the two balloons indicates that these bursts were temporal variations, not spatial structures. The data are consistent with an interval of enhanced reconnection and convection preceding each major enhancement in precipitation activity.

Holzworth, R. H.; Bering, E. A.; Reddell, B. D.; Kokorowski, M.; Bale, S.; Blake, J. B.; Collier, A. B.; Hughes, A. R.; Lay, E.; Lin, R. P.; McCarthy, M. P.; Millan, R. M.; Moraal, H.; O'Brien, T. P.; Parks, G. K.; Pulupa, M.; Sample, J. G.; Smith, D. M.; Stoker, P.; Woodger, L.

2005-12-01

80

Summer convection and lightning over the Mackenzie river basin and their Impacts during 1994 and 1995  

Microsoft Academic Search

Lightning activity over the Mackenzie basin has been examined for the summers of 1994 and 1995. In recent years, the lightning network operating in the Northwest Territories has detected an average of 118 K strikes per season. Positive lightning strikes (defined as lightning discharges lowering positive charge to the earth) typically comprise 12% of the total. The lightning activity during

B. Kochtubajda; R. E. Stewart; J. R. Gyakum; M. D. Flannigan

2002-01-01

81

Convections  

NSDL National Science Digital Library

This experiment demonstrates convection, the fundamental reason we have weather. Explore what happens when cold ice hits a tub of warm water. This activity guide includes a step-by-step instructional video.

Center, Saint L.

2013-01-30

82

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

USGS Publications Warehouse

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 measure by chemical weathering as a result of episodes of low rain rate and decreased rainfall pH during a storm.

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

1994-01-01

83

Atmosphere-ocean conditions jointly guide convection of the Boreal Summer Intraseasonal Oscillation: Satellite observations  

Microsoft Academic Search

The water-vapor and air-temperature profiles from the Atmospheric Infrared Sounder (AIRS), in combination with surface wind from Quick Scatterometer (QuikSCAT) and rainfall and sea surface temperature (SST) from Tropical Rainfall Measurement Mission (TRMM) Microwave Imager (TMI), are used to document surface conditions and vertical moist thermodynamic structures of the 2003–2006 Boreal Summer Intraseasonal Oscillation (BSISO) over the Indo-Pacific warm pool.

Bo Yang; Xiouhua Fu; Bin Wang

2008-01-01

84

Atmosphere-ocean conditions jointly guide convection of the Boreal Summer Intraseasonal Oscillation: Satellite observations  

Microsoft Academic Search

The water-vapor and air-temperature profiles from the Atmospheric Infrared Sounder (AIRS), in combination with surface wind from Quick Scatterometer (QuikSCAT) and rainfall and sea surface temperature (SST) from Tropical Rainfall Measurement Mission (TRMM) Microwave Imager (TMI), are used to document surface conditions and vertical moist thermodynamic structures of the 2003-2006 Boreal Summer Intraseasonal Oscillation (BSISO) over the Indo-Pacific warm pool.

Bo Yang; Xiouhua Fu; Bin Wang

2008-01-01

85

Arctic Storms and Their Links to Surface Energy Budget Changes at the Onset and End of the Summer Melt Season Over Pack Ice  

NASA Astrophysics Data System (ADS)

The length of the Arctic melt season has been observed to be increasing over the last two decades. However, the processes which initiate and end the summer melt season have not been studied in detail. Point observations at the Surface Heat Budget of the Arctic Ocean (SHEBA) site during the summer of 1998 suggest that Arctic storms over the pack ice at both ends of the melt season alter all of the terms of the surface energy budget, leading to the onset and end of the summer melt in late May or June and August, respectively. In particular, changes in longwave radiative conditions from clouds located in warm or cold air masses aloft produce key changes to the surface energy budget. This presentation will show these observations and examine the generality of the hypothesis using data from the Russian drifting stations, the North Pole Environmental Observatories, and Arctic Ocean Expedition-2001. The synoptic environment of the freeze-up process will be demonstrated with preliminary data from the recently completed Arctic Mechanisms of Interaction between the Surface and Atmosphere (AMISA) and Arctic Summer Cloud-Ocean Study (ASCOS) field programs.

Persson, O. P.; Solomon, A.; Shupe, M.; Gasiewski, A. J.

2008-12-01

86

Verification of Severe Local Storms Forecasts Issued by the National Severe Storms Forecast Center: 1992.  

National Technical Information Service (NTIS)

The SELS Unit of the National Severe Storms Forecast Center routinely issues convective outlooks and severe local storm watches to delineate areas that are favorable for development of severe local storms. The report summarizes verification of those forec...

R. W. Anthony

1993-01-01

87

Verification of Severe Local Storms Forecasts Issued by the National Severe Storms Forecast Center: 1993.  

National Technical Information Service (NTIS)

The SELS Unit of the National Severe Storms Forecast Center routinely issues convective outlooks and severe local storm watches to delineate areas that are favorable for development of severe local storms. During 1993 the SELS Unit issued 957 severe local...

R. W. Anthony

1994-01-01

88

VHF radar observed characteristics of convectively generated gravity waves during wet and dry spells of Indian summer monsoon  

NASA Astrophysics Data System (ADS)

A powerful VHF radar observed characteristics of Convectively generated Gravity Waves (CGW) excited during the wet and dry spells of Indian summer monsoon over a tropical station Gadanki (13.5°N, 79.2°E) are discussed. The characteristics of gravity waves in the lower stratosphere during these two spells are discussed in terms of their wavelet spectra along with height-time sections of vertical velocity. A total of 31 events are analyzed and in more than 50% of the events, the lower stratospheric gravity wave amplitudes were found to be relatively large in dry spell compared to that in the wet spell. The wavelet analysis of lower stratospheric vertical velocities showed a dominant periodicity of about ˜20-40 min in wet spell and ˜10-20 min in dry spell. The analysis also indicates that wet spell is found to be more conducive for the generation of gravity waves. However, the propagation of these waves into the stratosphere is found to be more efficient in dry spell of monsoon. The strengthening/weakening of the tropical easterly jet during wet/dry spell of monsoon is found to be the main reason for the inhibited/enhanced wave activity in the lower stratosphere during wet/dry spell. The present analysis also suggests that the static stability of the mid- and upper-troposphere during these two spells have implications in the observed frequency of the CGW. Thus, the present analyses brought out for the first time the features of CGW during two distinctive regimes of convective systems and emphasized the importance of prevailing background conditions in exciting/filtering them.

Uma, K. N.; Kishore Kumar, Karanam; Narayana Rao, T.

2011-05-01

89

Role of convection in redistributing formaldehyde to the upper troposphere over North America and the North Atlantic during the summer 2004 INTEX campaign  

Microsoft Academic Search

Measurements of formaldehyde (CH2O) from a tunable diode laser absorption spectrometer (TDLAS) were acquired onboard the NASA DC-8 aircraft during the summer 2004 INTEX-NA campaign to test our understanding of convection and CH2O production mechanisms in the upper troposphere (UT, 6-12 km) over continental North America and the North Atlantic Ocean. The present study utilizes these TDLAS measurements and results

Alan Fried; Jennifer R. Olson; James G. Walega; Jim H. Crawford; Gao Chen; Petter Weibring; Dirk Richter; Chad Roller; Frank Tittel; Michael Porter; Henry Fuelberg; Jeremy Halland; Timothy H. Bertram; Ronald C. Cohen; Kenneth Pickering; Brian G. Heikes; Julie A. Snow; Haiwei Shen; Daniel W. O'Sullivan; William H. Brune; Xinrong Ren; Donald R. Blake; Nicola Blake; Glen Sachse; Glenn S. Diskin; James Podolske; Stephanie A. Vay; Richard E. Shetter; Samuel R. Hall; Bruce E. Anderson; Lee Thornhill; Antony D. Clarke; Cameron S. McNaughton; Hanwant B. Singh; Melody A. Avery; Gregory Huey; Saewung Kim; Dylan B. Millet

2008-01-01

90

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)

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.

Bao, Yan

2013-12-01

91

Magnetospheric electric fields and plasma sheet injection to low L-shells during the 4–5 June 1991 magnetic storm: Comparison between the Rice Convection Model and observations  

Microsoft Academic Search

The major magnetic storm of 4–5 June 1991 was well observed with the Combined Release and Radiation Experiment (CRRES) satellite in the duskside inner magnetosphere and with three Defense Meteorological Satellite Program (DMSP) spacecraft in the polar ionosphere. These observations are compared to results from the Rice Convection Model (RCM), which calculates the inner magnetospheric electric field and particle distribution

T. W. Garner; R. A. Wolf; R. W. Spiro; W. J. Burke; B. G. Fejer; S. Sazykin; J. L. Roeder; M. R. Hairston

2004-01-01

92

Contribution of the MODIS instrument to observations of deep convective storms and stratospheric moisture detection in GOES and MSG imagery  

Microsoft Academic Search

Past studies based on the NOAA\\/AVHRR and GOES I-M imager instruments have documented the link between certain storm top features referred to as the “cold-U\\/V” shape in the 10–12 ?m IR band imagery and plumes of increased 3.7\\/3.9 ?m band reflectivity. Later, similar features in the 3.7\\/3.9 ?m band have been documented in the AVHRR\\/3 1.6 ?m band imagery.The present work focuses on storm

Martin Setvák; Robert M. Rabin; Pao K. Wang

2007-01-01

93

Roles of the tropical convective activities over different regions in the earlier onset of the South China Sea summer monsoon after 1993  

NASA Astrophysics Data System (ADS)

The South China Sea summer monsoon (SCSSM) onset experiences evidently an interdecadal change around mid-1990s. Generally, the SCSSM broke out half a month earlier during 1994-2010 than IN 1978-1993. Possible causes are analyzed in this study. The results suggest that the earlier onset of the SCSSM is due to earlier retreat of the subtropical high (STH) over the western Pacific, which is closely related to enhanced intraseasonal oscillations of tropical convections. The enhanced convective activities can be found in three regions: the eastern tropical Indian Ocean (TIO), the equatorial SCS-Kalimantan (ESK) and the tropical western Pacific (TWP). Both convections in the TIO and the ESK are greatly influenced by the interaction of the westerly wind from the TIO and the easterly wind from the TWP. The convections in the TIO are never found to propagate to the east of 100°E, while those in the ESK are usually quite weak and not great help to the SCSSM onset. Our results suggest that the earlier retreat of the STH is mainly caused by the enhanced convections in the TWP, while the later may be the consequence of warming over the TWP on the interdecadal timescale. Therefore, the La Niña-like interdecadal change of the sea surface temperature (SST) in the Pacific is likely to be responsible for the interdecadal advance of the SCSSM onset.

Yuan, Fang; Chen, Wen

2013-07-01

94

Warm Season Convective Storm Structures over the Northeastern U.S. and their Interaction with the Marine Environment  

NASA Astrophysics Data System (ADS)

The evolution of organized convective structures over the northeastern U.S. from initiation to decay is influenced by a variety of geographical features (elevated terrain, coastal boundary). Warm season convection over this region has been relatively unexplored, especially the interaction between quasi-linear convective structures (QLCSs) and the marine environment. This thesis is the first study to systematically explore the evolving convective structures over the Northeast, with particular emphasis on the coastal region from New Jersey northeastward to Rhode Island, through observational analysis as well as high-resolution simulations of 2 representative case studies. Organized convective structures over the Northeast during the warm season (May--August) were identified and classified into 3 main groups, including cells, quasi-linear convection, and nonlinear structures. Across the Northeast, the occurrence of all convection decreases from the western Appalachian slopes eastward to the Atlantic coast. Composite analysis highlights the importance of terrain during the initiation of cellular convection, with a majority developing in orographically-favored upslope areas. Linear and nonlinear convection are dynamically supported with a weaker terrain influence. Composite analyses reveal that QLCSs that decay upon encountering the Atlantic coastline organize along a surface pressure trough, collocated with a region of low-level frontogenesis. Those that maintain their intensity organize downstream of a surface trough within low-level warm air advection with higher saturation in the lowest 100 hPa compared to decaying events. Sensitivity studies of a representative decaying linear event illustrate that evaporative cooling causes the development of a strong a cold pool that overwhelms the weak ambient vertical wind shear downwind of the system causing the system to decay. During this event, the role of the marine layer appears secondary. For the maintaining event, the marine layer allows the magnitude of the surface winds to be larger compared to the land due to decreasing surface friction, which increases the vertical wind shear and helps to maintain the convection. Sensitivity tests show that by increasing the roughness length over the ocean to an equivalent land value, thus decreasing vertical wind shear, the maintaining event decays closer to the coastline compared to the control run.

Lombardo, Kelly

95

Meteorological indicators of summer precipitation chemistry in central Pennsylvania  

Microsoft Academic Search

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,

Uri Dayan; Dennis Lamb

2003-01-01

96

Rocket dust storms and detached dust layers in the Martian atmosphere  

NASA Astrophysics Data System (ADS)

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.

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

2013-04-01

97

Boreal summer intraseasonal variability simulated in the NCEP climate forecast system: insights from moist static energy budget and sensitivity to convective moistening  

NASA Astrophysics Data System (ADS)

The NCEP Climate Forecast System (CFS) with the relaxed Arakawa Schubert (RAS, hereafter referred to as CTRL) convection scheme of Moorthi and Suarez exhibits better performance in representing boreal summer tropical intraseasonal variability as compared with a simulation using simplified Arakawa-Schubert scheme. The intraseasonal moist static energy (MSE) budget is analyzed in this version of the CFS model (CTRL), which produces realistic eastward and northward propagation characteristics. The moist and thermodynamic processes involved in the maintenance and propagation of the poleward moving intraseasonal oscillation (ISO) disturbances are examined here. Budget diagnostics show that horizontal MSE advection is the principal component of the budget, contributing to the poleward movement of the convection. The injection of MSE moistens the atmosphere north of the convective area causing the poleward movement of convection by destabilization of the atmosphere. The moistening process is mainly contributed by the climatological wind acting on the anomalous moisture gradient as confirmed from the examination of moisture advection equation. While surface enthalpy fluxes (consisting of radiative and surface turbulent heat fluxes) maintain the ISO anomalies, they oppose the MSE tendency due to horizontal advection thus regulating the poleward propagation characteristics. In addition, the model results show that wind-evaporation feedback dominates over cloud-radiation feedback for ISO propagation; this is in contrast to our estimates using the newly available European Centre for Medium Range Weather Forecasts Interim reanalysis. Sensitivity experiments suggest that intraseasonal variability in the CFS model with the RAS scheme is highly sensitive to the parameterization of both the shallow convection and the convective rain evaporation and downdrafts. Removal of these components adversely affects the propagation characteristics and greatly reduces the amplitude of intraseasonal variability. Our results support the primary importance of the moisture preconditioning ahead of the ISO and the physical relationship between moisture and precipitation. For realistic ISO simulations, models need to represent these features appropriately.

Sooraj, K. P.; Seo, Kyong-Hwan

2012-12-01

98

Boreal summer intraseasonal variability simulated in the NCEP climate forecast system: insights from moist static energy budget and sensitivity to convective moistening  

NASA Astrophysics Data System (ADS)

The NCEP Climate Forecast System (CFS) with the relaxed Arakawa Schubert (RAS, hereafter referred to as CTRL) convection scheme of Moorthi and Suarez exhibits better performance in representing boreal summer tropical intraseasonal variability as compared with a simulation using simplified Arakawa-Schubert scheme. The intraseasonal moist static energy (MSE) budget is analyzed in this version of the CFS model (CTRL), which produces realistic eastward and northward propagation characteristics. The moist and thermodynamic processes involved in the maintenance and propagation of the poleward moving intraseasonal oscillation (ISO) disturbances are examined here. Budget diagnostics show that horizontal MSE advection is the principal component of the budget, contributing to the poleward movement of the convection. The injection of MSE moistens the atmosphere north of the convective area causing the poleward movement of convection by destabilization of the atmosphere. The moistening process is mainly contributed by the climatological wind acting on the anomalous moisture gradient as confirmed from the examination of moisture advection equation. While surface enthalpy fluxes (consisting of radiative and surface turbulent heat fluxes) maintain the ISO anomalies, they oppose the MSE tendency due to horizontal advection thus regulating the poleward propagation characteristics. In addition, the model results show that wind-evaporation feedback dominates over cloud-radiation feedback for ISO propagation; this is in contrast to our estimates using the newly available European Centre for Medium Range Weather Forecasts Interim reanalysis. Sensitivity experiments suggest that intraseasonal variability in the CFS model with the RAS scheme is highly sensitive to the parameterization of both the shallow convection and the convective rain evaporation and downdrafts. Removal of these components adversely affects the propagation characteristics and greatly reduces the amplitude of intraseasonal variability. Our results support the primary importance of the moisture preconditioning ahead of the ISO and the physical relationship between moisture and precipitation. For realistic ISO simulations, models need to represent these features appropriately.

Sooraj, K. P.; Seo, Kyong-Hwan

2013-09-01

99

Multiparameter Radar Observations of Time Evolution of Convective Storms: Evaluation of Water Budgets and Latent Heating Rates  

Microsoft Academic Search

One advantage of dual-polarization radars is the ability to differentiate between water and ice phases in storms. The application of difference reflectivity ( ZDP) in the analysis of mixed-phase precipitation is presented. Here, ZDP analysis is used to obtain the fraction of water and ice in mixed-phase precipitation. The techniques developed are applied to data collected on 9 August 1991

Hui Tong; V. Chandrasekar; K. R. Knupp; James Stalker

1998-01-01

100

Lightning location relative to storm structure in a leading-line, trailing-stratiform mesoscale convective system  

NASA Astrophysics Data System (ADS)

Horizontal and line-normal, vertical cross-sections and composite images of Dallas-Fort Worth Lightning Detection and Ranging (LDAR II) VHF radiation sources and radar reflectivity over a 30-min period provide a unique perspective on lightning pathways within a leading-line, trailing-stratiform (LLTS) mesoscale convective system (MCS) on 16 June 2002. The overwhelming majority of VHF lightning sources occurred within the leading convective line in a bimodal pattern in the vertical. Assuming that VHF source density maxima were most likely associated with positive charge, then the LDAR II observations suggest that the gross charge structure of the convective region of the MCS was characterized by a tripole with net positive charge centered at 4.5 km AGL (3°C) and 9.5 km AGL (-35°C) and net negative charge centered roughly in the relative minimum of the VHF source density maximum at 7 km AGL (-17°C). A persistent lightning pathway and inferred positive charge zone sloped rearward (by 40-50 km) and downward (by 4-5 km) from the upper VHF source maximum in the convective line, through the transition zone, and into the radar bright band of the stratiform region. In the stratiform region, VHF lightning sources and inferred positive charge were concentrated in three layers centered at 4.5, 6, and 9 km AGL (2°C, -11°C, and -31°C, respectively), consistent with past electric field studies of symmetric LLTS MCSs. Positive cloud-to-ground lightning flashes in the stratiform region were initiated in the convective line and followed the slanting pathway from the top of convective cores to the stratiform precipitation, where they were horizontally extensive, layered, and highly branched. The sloping lightning pathway was identical to hypothetical trajectories taken by snow particles. These observations provide further support for the advection of charge on snow along the sloping pathway and the in situ generation of charge in the horizontal lightning layers as primary contributors to electrification and positive lightning production rearward of the convective line.

Carey, Lawrence D.; Murphy, Martin J.; McCormick, Tracy L.; Demetriades, Nicholas W. S.

2005-02-01

101

Desert rain storms and flash floods: Insights gained from space-time characterization of convective rain cells  

NASA Astrophysics Data System (ADS)

The occurrence of an extreme flash-flood at a given catchment is the final and powerful result of several meteorological and hydrological processes. Rain storm properties, including rain accumulations, rain intensities and space-time distributions, are most important in determining flash flood magnitudes. Catchment properties are also of major importance as they define the catchment-dependent sensitivity of flash-flood generation to rain properties. The presented study looks into these relationships focusing on catchments in the semi-arid and arid regions of the south-eastern Mediterranean. A special attention is given to the space-time rainfall patterns that are derived from meteorological radar data and allow a better view of the rainstorm structure, evolvement and movement in relation to the flooded catchment. The study is conducted through analysis of the highest recorded flash-flood events for which radar data are available. Past studies and new analyses are synthesized to provide more insights into the storm-catchment hydrological interactions during extreme flash flood events.

Morin, E.

2012-04-01

102

Robustness and sensitivities of central U.S. summer convection in the super-parameterized CAM: Multi-model intercomparison with a new regional EOF index  

NASA Astrophysics Data System (ADS)

Mesoscale convective systems (MCSs) can bring up to 60% of summer rainfall to the central United States but are not simulated by most global climate models. In this study, a new empirical orthogonal function based index is developed to isolate the MCS activity, similar to that developed by Wheeler and Hendon (2004) for the Madden-Julian Oscillation. The index is applied to compactly compare three conventional- and super-parameterized (SP) versions (3.0, 3.5, and 5.0) of the National Center for Atmospheric Research Community Atmosphere Model (CAM). Results show that nocturnal, eastward propagating convection is a robust effect of super-parameterization but is sensitive to its specific implementation. MCS composites based on the index show that in SP-CAM3.5, convective MCS anomalies are unrealistically large scale and concentrated, while surface precipitation is too weak. These aspects of the MCS signal are improved in the latest version (SP-CAM5.0), which uses high-order microphysics.

Kooperman, Gabriel J.; Pritchard, Michael S.; Somerville, Richard C. J.

2013-06-01

103

What is a geomagnetic storm?  

Microsoft Academic Search

The authors present a review of geomagnetic storm research. They examine the interaction of the solar wind with the magnetosphere. They argue that a storm results from the extended interaction of the solar wind\\/magnetosphere when a strong convection electric field is generated, which is able to perturb the ring current above some threshold level, triggering the event. They touch on

W. D. Gonzales; J. A. Joselyn; Y. Kamide; H. W. Kroehl; G. Rostoker; B. T. Tsurutani; V. M. Vasyliunas

1994-01-01

104

A diagnostic study of convective environment leading to heavy rainfall during the summer monsoon 2010 over Pakistan  

NASA Astrophysics Data System (ADS)

Observational data and outputs from the Weather Research and Forecasting (WRF) model were used to investigate the atmospheric processes that led to an unusual extreme precipitation resulting to a destructive flash flooding, loss of life and property in northern Pakistan on 28-29 July, 2010. In this work, the model's inner most domain with horizontal grid spacing of 3 km, successfully simulated the extreme precipitation with values up to 120 mm within 24 h. The useful dynamic and thermodynamic variables ????/? and ????/? are used to understand their roles in the atmospheric environment conducive to severe weather system. The results show that prior to the extreme rainfall, distribution of high potential vorticity anomaly in the mid-tropospheric level is conducive for the development of strong mesoscale convective vortex and large-scale cyclonic circulation. Moreover, the resulting symmetric instability due to negative moist potential vorticity anomaly located over the area significantly enhanced the vertical ascending and precipitation in the convective region. Another prominent factor was the interaction between the upper-level westerly trough and the east-west moving monsoon low clearly discernible from the synoptic situation. The aforementioned findings may be responsible for the extreme rainfall over the selected area.

Ullah, Kalim; Shouting, Gao

2013-02-01

105

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

SciTech Connect

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.

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

2011-02-13

106

Winter Storms  

NSDL National Science Digital Library

This site offers general background about winter storms as well as interactive activities to teach visitors about these storms. It also offers a teachers guide to using this site and links to other weather-related pages. There are four main topics: All About Winter Storms, Interactive Weather Maker, Interactive Winter Storm Timeline, and Ask Our Winter Storm Expert. All About Winter Storms gives general background information an a glossary of weather terms. The Weather Maker offers students a chance to control the weather through a simulation in which they affect the weather by changing variables such as humidity, equatorward temperature, and polarward temperature. The Storm Timeline offers students a chance to move up and down the timeline to learn about past winter storms. In Ask the Expert, students can email their questions to a winter storm expert and have them answered. This section also gives a brief biography of the expert.

1996-01-01

107

The importance of convective equilibrium and non-equilibrium conditions for the characterization of the predictability of severe storms in Italy  

NASA Astrophysics Data System (ADS)

The predictability of severe rainfall by means of high resolution numerical weather models is a long standing issue for meteorological community. This study intends to provide an objective system to single out heavy rainfall events and to classify them on the basis of duration, spatial extent and large/small-scale triggering. Italy has built up one of the densest hourly-reporting raingauge networks and its data are presently archived and available. The first part of the work was devoted to developing a procedure to identify extreme precipitation events and its application to the full set of raingauges (about 1700 stations) all over Italy for the period 2006-2008. This method allowed for the classification of about 100 events, either as long-lived (if lasting more than 12 hours) and spatially distributed (more than 50x50 km2), or brief and localized, (having a shorter duration and a minor spatial extent). For each of aforementioned events, the observed rainfall distributions have been compared with COSMO-I7 forecasts using spectral and statistical analyses. The second part of the work examines the hypothesis that the differences in predictability between these two classes of event are associated with different mechanisms of control of the precipitation by dynamical processes in the atmosphere. In particular, we ask whether the forcing of convection is sufficiently homogeneous and slowly varying that the convection can be considered to be in equilibrium or, otherwise, the outbreak of convection is more abrupt and small-scale driven (Done et al., 2006). Using ECMWF analysis (ERA-Interim) of convective available potential energy (CAPE), and precipitation analysed from the rain gauge network, we calculate the magnitude and time evolution of the timescale of convective adjustment for the severe events singled out in the first part. As expected, the events with higher predictability are mainly associated with short convective adjustment timescales which indicate equilibrium convection, while the short-lived, less predictable events have long convective timescales.

Molini, Luca; Parodi, Antonio; Rebora, Nicola; Craig, George C.

2010-05-01

108

What is a geomagnetic storm?  

SciTech Connect

The authors present a review of geomagnetic storm research. They examine the interaction of the solar wind with the magnetosphere. They argue that a storm results from the extended interaction of the solar wind/magnetosphere when a strong convection electric field is generated, which is able to perturb the ring current above some threshold level, triggering the event. They touch on interrelationships of the solar wind/magnetosphere/ionosphere as it bears on this problem, and offer ideas for continuing research directions to address the origin of geomagnetic storms.

Gonzales, W.D. [Instituto de Pesquisas Espaciais, Sao Paulo (Brazil); Joselyn, J.A. [National Oceanic and Space Administration, Boulder, CO (United States); Kamide, Y. [Nagoya Univ., Toyokawa (Japan)] [and others

1994-04-01

109

Geologic impact of methane storms on Titan  

Microsoft Academic Search

Titan's surface is shaped by numerous of extended fluvial valleys. The most likely scenario for their development is atmospheric precipitation. Atmospheric modelling suggests precipitation through episodic methane convective storms rather than steady precipitation. This study aims to test whether Titan's valleys developed from steady rainfall or through episodic storms with long recurrence intervals. Data from the Cassini RADAR-SAR sensor provides

Mirjam Langhans; Ralf Jaumann; Katrin Stephan; Robert H. Brown; Bonnie J. Buratti; Roger N. Clark; Kevin H. Baines; Philip D. Nicholson; Ralph D. Lorenz; Christophe Sotin

2010-01-01

110

Storm Surge.  

National Technical Information Service (NTIS)

Storm surges, which are departures of sea level from normal, are of great concern in the New York Bight area whenever hurricanes or extrapropical storms approach or cross the coastline. During such storms, sea level can increase to more than 10 feet (3.1 ...

N. A. Pore C. S. Barrientos

1976-01-01

111

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

Microsoft Academic Search

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

A. Sánchez-Lavega; T. del Río-Gaztelurrutia; R. Hueso; J. M. Gómez-Forrellad; J. F. Sanz-Requena; J. Legarreta; E. García-Melendo; F. Colas; J. Lecacheux; L. N. Fletcher; D. Barrado y Navascués; D. Parker; T. Akutsu; T. Barry; J. Beltran; S. Buda; B. Combs; F. Carvalho; P. Casquinha; M. Delcroix; S. Ghomizadeh; C. Go; J. Hotershall; T. Ikemura; G. Jolly; A. Kazemoto; T. Kumamori; M. Lecompte; P. Maxson; F. J. Melillo; D. P. Milika; E. Morales; D. Peach; J. Phillips; J. J. Poupeau; J. Sussenbach; G. Walker; S. Walker; T. Tranter; A. Wesley; T. Wilson; K. Yunoki

2011-01-01

112

Ionospheric response to the corotating interaction region–driven geomagnetic storm of October 2002  

Microsoft Academic Search

Unlike the geomagnetic storms produced by coronal mass ejections (CMEs), the storms generated by corotating interaction regions (CIRs) are not manifested by dramatic enhancements of the ring current. The CIR-driven storms are however capable of producing other phenomena typical for the magnetic storms such as relativistic particle acceleration, enhanced magnetospheric convection and ionospheric heating. This paper examines ionospheric plasma anomalies

D. Pokhotelov; C. N. Mitchell; P. T. Jayachandran; J. W. MacDougall; M. H. Denton

2009-01-01

113

Convective Available Potential Energy (CAPE) Increases in the Great Lakes Region, 1979-2010  

NASA Astrophysics Data System (ADS)

This paper explores trends in convective available potential energy (CAPE) over part of the Laurentian Great Lakes region, using data from the NCEP North American Regional Reanalysis (1979-2010). CAPE aids forecasters in predicting the behavior of deep moist convection, and is directly proportional to theoretical maximum updraft velocity via buoyant parcel theory. Over the period of analysis, the region has experienced a marked and statistically significant (95% CI) trend in CAPE in June, increasing at rates of 20 to 30% per decade. This trend is likely explained by an even stronger trend in boundary layer specific humidity (99% CI), given that boundary layer temperatures have warmed only slightly in the region and no appreciable temperature trend is found in the mid-troposphere, at least in this dataset. The smoothed annual cycle of CAPE in the region exhibits a traditional signal, with the highest values observed during the summer months. However, the "onset date" of appreciable CAPE (defined here as at least 200 J/kg) is trending earlier, by roughly one week per decade. There is no similar trend in the termination of these seasonal CAPE values; consequently, the length of the "CAPE season" has increased during the analysis period. Although regionally-averaged CAPE cannot explain the strength of any single convective storm, these findings have important implications for regional climatologies of convection and for climate studies that consider convective storms.

Kirkpatrick, C.

2011-12-01

114

Chasing Storms  

NSDL National Science Digital Library

John Monteverdi created this website to educate and entertain visitors in the science of storm chasing. Online storm journals for Spring Storm Chases from 1994 to the present take visitors through the life of a storm chaser. Throughout his discussions, the author provides weather charts and satellite images to assist visitors with the weather-related concepts. The site contains countless pictures of tornadoes and the destruction they leave behind. Although some of the amazing images take a few minutes to download, visitors will find that it is worth the wait.

Monteverdi, John

115

Hail Storms  

NSDL National Science Digital Library

This website contains photos and information about hail and hail storms as a weather phenomenon. The images show hail stones, storms with falling hail, cloud formations, and damage from hail. Each photo has a description with information about the weather system and occurrence of hail.

Moore, Gene

116

August 28, 1978, Storm 1. GEOS 2 observations of the initial magnetopause crossings and STARE observations near the ionospheric convection reversal  

SciTech Connect

During the postdawn period on August 28, 1978, from approx.0750 to 0830 magnetic local time, the magnetopause moved several earth radii inward to less than 6.6 R/sub E/, where it remained until approx.1120 MLT. As the magnetopause approached the earth, the poleward boundary of the westward auroral electrojet moved southward to geomagnetic latitudes less than 66/sup 0/. Fortuitously, the geostationary satellite GEOS 2 was located in this morning sector during this entire period, and experienced a series of magnetopause crossings. In quiet periods GEOS 2 was conjugate to that area of the lower E region which constituted the field-of-view of the Scandinavian Twin Auroral Radar Experiment (STARE) radars. This paper compares the magnetospheric satellite and ionospheric radar observations. The combined observations suggest that, near the dawnside magnetopause, large-scale merging was occurring, while in the ionosphere, the convection reversal region and poleward portion of the auroral zone underwent major equatorward shifts and featured prominent sunward moving ULF pulsations. Between the magnetopause and ionosphere a large increase in the ring current accompanied the equatorward shift of the convection reversal.

Sofko, G.J.; Korth, A.; Kremser, G.

1985-02-01

117

Empirical Data Fusion for Convective Weather Hazard Nowcasting  

NASA Astrophysics Data System (ADS)

This paper describes a statistical analysis approach to developing an automated convective weather hazard nowcast system suitable for use by aviation users in strategic route planning and air traffic management. The analysis makes use of numerical weather prediction model fields and radar, satellite, and lightning observations and derived features along with observed thunderstorm evolution data, which are aligned using radar-derived motion vectors. Using a dataset collected during the summers of 2007 and 2008 over the eastern U.S., the predictive contributions of the various potential predictor fields are analyzed for various spatial scales, lead-times and scenarios using a technique called random forests (RFs). A minimal, skillful set of predictors is selected for each scenario requiring distinct forecast logic, and RFs are used to construct an empirical probabilistic model for each. The resulting data fusion system, which ran in real-time at the National Center for Atmospheric Research during the summer of 2009, produces probabilistic and deterministic nowcasts of the convective weather hazard and assessments of the prediction uncertainty. The nowcasts' performance and results for several case studies are presented to demonstrate the value of this approach. This research has been funded by the U.S. Federal Aviation Administration to support the development of the Consolidated Storm Prediction for Aviation (CoSPA) system, which is intended to provide convective hazard nowcasts and forecasts for the U.S. Next Generation Air Transportation System (NextGen).

Williams, J.; Ahijevych, D.; Steiner, M.; Dettling, S.

2009-09-01

118

Storm Research.  

National Technical Information Service (NTIS)

This report presents some lightning observations made from a mobile laboratory jointly equipped with support by NSSL, UM and ONR. The pertinent findings of the work are summarized below: (1) Electrical measurements were made on severe storms with the mobi...

R. T. Arnold

1979-01-01

119

Day-time identification of summer hailstorm cells from MSG data  

NASA Astrophysics Data System (ADS)

Identifying deep convection is of paramount importance, as it may be associated with extreme weather that has significant impact on the environment, property and the population. A new method, the Hail Detection Tool (HDT), is described for identifying hail-bearing storms using multi-spectral 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 Detection algorithm (HD) for the identification of hail-bearing clouds among cumulonimbus systems detected by CM. Both CM and HD are based on logistic regression models trained with multi-spectral MSG data-sets comprised of summer convective events in the middle Ebro Valley between 2006-2010, and detected by the RGB 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 HD 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 (POD) was 76.9% and False Alarm Ratio 16.7%.

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

2013-10-01

120

Will moist convection be stronger in a warmer climate?  

NASA Astrophysics Data System (ADS)

The intensity of moist convection is an important diagnostic of climate change not currently predicted by most climate models. We show that a simple estimate of the vertical velocity of convective updrafts in a global climate model reproduces observed land-ocean differences in convective intensity. Changes in convective intensity in a doubled CO2 simulation are small because the tropical lapse rate tends to follow a moist adiabatic profile. However, updrafts strengthen by ~1 m s-1 with warming in the lightning-producing regions of continental convective storms, primarily due to an upward shift in the freezing level. For the western United States, drying in the warmer climate reduces the frequency of lightning-producing storms that initiate forest fires, but the strongest storms occur 26% more often. For the central-eastern United States, stronger updrafts combined with weaker wind shear suggest little change in severe storm occurrence with warming, but the most severe storms occur more often.

Del Genio, Anthony D.; Yao, Mao-Sung; Jonas, Jeffrey

2007-08-01

121

A Study of a Dryline Convective Downburst  

Microsoft Academic Search

During the afternoon of 15 June 2005, convective storms developed along and west of the dryline over eastern Colorado and New Mexico. One such storm tracked eastward into Cimarron County, Oklahoma and produced a strong downburst at Kenton. The dryline, as it tracked eastward over the western Oklahoma Panhandle, established favorable conditions for hybrid microbursts by enhancing vertical circulation west

Kenneth Pryor

2006-01-01

122

Konvection (Convection).  

National Technical Information Service (NTIS)

Basic features in possible convection types in microgravity are discussed. Characteristic data are analyzed concerning free and forced convection, thermal convection, Marangoni and b-jitter (time dependent acceleration) convection.

G. S. R. Sarma

1987-01-01

123

Average storm duration and seasonal precipitation rates for the northeast sector of the United States  

SciTech Connect

Regional and seasonal averages of storm duration and precipitation rates for the northeast sector of the United States are needed as input variables in models aimed at describing precipitation processes relating to acid rain and other problems. Hourly precipitation data for 78 first order weather stations for four summer months and three winter months were used to calculate the regional average storm duration and average precipitation rates over the 19 northeastern states north of 36/sup 0/N latitude and east of 92/sup 0/W longitude. Average storm duration for summer (June-August), and winter (December-February) seasons are calculated based on a scheme that allows a period of up to three dry hours in summer storms, and up to six dry hours in winter storms to be included as part of the same storm. Thus, each storm consists of one or more precipitation periods or events. The arithmetic mean of event precipitation rates was used to determine the average precipitation rates for summer and winter season storms. The data suggest a preferred summer storm time duration of about three hours and a preferred winter storm time scale of about 26 hours. The summer storms typically consist of one rain event lasting about three hours with rain rates averaging 2.5 mm h/sup -1/. The 26 hour winter storm averages about three precipitation periods (or rain bands). Each period lasts about six hours and has an average precipitation rate of 0.9 mm h/sup -1/.

Thorp, J.M.; Scott, B.C.

1980-08-01

124

The flywheel effect: Ionospheric currents after a geomagnetic storm  

Microsoft Academic Search

In the period following a geomagnetic storm the high-latitude, magnetospheric-driven convection pattern is normally weak. However, the neutral circulation, set up by ion-neutral momentum coupling during the main phase of the storm, may continue for several hours after the storm has ended. This persistent neutral circulation has the potential to drive Hall currents for some hours. In this paper the

W. Deng; T. L. Killeen; A. G. Burns; R. G. Roble

1991-01-01

125

Magnetic Storms  

Microsoft Academic Search

DR. CHREE contends that magnetic observations have now reached a high pitch of perfection, and that their discussion is not lightly to be undertaken by outsiders. That is no doubt so, and there must be many features about magnetic storms which are known only to experts. But when we find experts in doubt on such a fundamental matter as whether

Oliver Lodge

1909-01-01

126

IDF relationships using bivariate copula for storm events in Peninsular Malaysia  

NASA Astrophysics Data System (ADS)

We derive IDF points of convective storms by using the copula method. The correlation between storm intensity and duration is negative and moderate. The Frank and Gaussian copula are suitable for storms in Peninsular Malaysia. We compare the results with the IDF curves from the univariate approach. The IDF points from both methods are in agreement with each other.

Ariff, N. M.; Jemain, A. A.; Ibrahim, K.; Wan Zin, W. Z.

2012-11-01

127

Modified Volland-Stern Stormtime Convection Simulation  

NASA Astrophysics Data System (ADS)

The Volland-Stern electric potential model is one of the most widely used model for stormtime convection simulations. The Volland-Stern potentials are given by ? = AL? sin(? ) where A is a function that depends on Kp and ? is the shielding factor. The shielding factor is kept constant and the most common value assigned to ? is 2. According to a recent study by Boonsiriseth et al. [2001], the Volland-Stern model greatly under-estimates convection at low L during the main phase of geomagnetic storms. It also fails to mimic the high time resolution variations in convection. In this study, we will attempt to improve the Volland-Stern Model by varying the ? factor according to a formulated relationship to IMF B\\( z \\). The study shows that by varying ? , the convection patterns changes drastically throughout the different phases of the storm. This initial study simulates the MACEP patterns for the Jan. 10, 1997 storm [Boonsiriseth et al., 2001].

Boonsiriseth, A.; Thorne, R. M.

2001-12-01

128

Generation Mechanisms of Convectively Forced Internal Gravity Waves and Their Propagation to the Stratosphere  

Microsoft Academic Search

Characteristics of gravity waves induced by mesoscale convective storms and the gravity wave sources are investigated using a two-dimensional cloud-resolving numerical model. In a nonlinear moist (control) simulation, the convective system reaches a quasi-steady state after 4 h in which convective cells are periodically regenerated from a gust front updraft. In the convective storms, there are two types of wave

In-Sun Song; Hye-Yeong Chun

2003-01-01

129

POCATELLO STORM DRAIN STUDY, BANNOCK COUNTY, IDAHO - 1979  

EPA Science Inventory

The City of Pocatello (17040208) storm drains were sampled during a winter snowmelt period and during a summer rainstorm. Chemical analyses of the drain water indicated levels of suspended solids, total solids, Chemical Oxygen Demand, sodium, potassium, chloride, fluoride, arsen...

130

Hydrochemical response during storm events in a South African mountain catchment: the influence of antecedent conditions  

Microsoft Academic Search

The influence of different antecedent conditions on hydrochemical response during storm events was investigated in a small, south-western Cape mountain catchment. Winter and summer storms (four in total) were sampled both before and after the catchment was deliberately burnt. During winter storms, discharge responded rapidly to rainfall, and direct runoff represented the major component of streamflow. Marked lags were observed

D. L. Britton; J. A. Day; M.-P. Henshall-Howard

1993-01-01

131

Ionospheric signatures of magnetospheric convection  

NASA Astrophysics Data System (ADS)

The average patterns of ionospheric convection observed with the Chatanika incoherent scatter radar, when mapped along magnetic field lines to the equatorial plane, delineate regions of earthward convection within the magnetotail that either proceed sunward to the dayside magnetopause (where reconnection with the IMF can occur) or that join the antisunward circulation along the magnetospheric flanks at dusk and dawn. An examination of summer and winter ionospheric convection patterns in terms of the corresponding magnetospheric circulation patterns shows that ionospheric ionization troughs at dusk and dawn are associated with the sunward convection of low density plasma from the night sector, and that plasma in the vicinity of the dawn and dusk electric field reversals circulates at high latitudes away from the solar ionization source at noon. Plasma exiting from the polar cap is convected away from midnight in the equatorward portion of the regions of sunward convection at auroral latitudes.

Foster, J. C.

1984-02-01

132

Rain in Shallow and Deep Convection Measured with a Polarimetric Radar  

Microsoft Academic Search

The authors contrast rainfall in two Oklahoma squall lines: one with deep convection occurred in the spring and the other with shallower convection in the winter. Both passed over a micronetwork of densely spaced rain gauges and were observed with the National Severe Storm Laboratory's polarimetric weather radar. Polarimetric measurements reveal differences in storm structure that in turn imply that

Alexander V. Ryzhkov; Dusan S. Zrni

1996-01-01

133

Winter storms  

NSDL National Science Digital Library

This project explores factors that help create severe winter weather. An interactive simulation provides hands-on experience, followed by guiding questions and resource exploration. Weather affects our everyday lives. Some days it's sunny and some days its not. The years weather is split up into seasons. 1. What are the four seasons? 2. What kind of weather do you see in the summer? 3. What kind of weather is unique to winter? 4. ...

Brieanne

2011-02-14

134

Research Opportunities at Storm Peak Laboratory  

NASA Astrophysics Data System (ADS)

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.

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

2006-12-01

135

Solar Storm Threat Analysis  

Microsoft Academic Search

[Abstract] Most solar storms produce only minor disquieting affects on Earth. Typically one might expect short-term electrical power blackouts, short lived communication outages, rerouting of aircraft, loss of a few satellites and a beautiful “aurora borealis” in the nights sky from a large solar storm. But as the intensity of a solar storm increases like a wild beast, the storm

James A. Marusek

2007-01-01

136

Winter storms over Canada  

Microsoft Academic Search

Various type of winter storms occur over Canada and produce major impacts on society. Canada is subjected to extra?tropical cyclones with all their embedded structures, as well as blizzards, mountain?induced storms, lake effect storms and polar lows. Many of these storms are accompanied by heavy precipitation in the form of snow or freezing precipitation, bitterly cold conditions, strong winds, and

R. E. Stewart; D. Bachand; R. R. Dunkley; A. C. Giles; B. Lawson; L. Legal; S. T. Miller; B. P. Murphy; M. N. Parker; B. J. Paruk; M. K. Yau

1995-01-01

137

The step-mountain eta coordinate model: Further developments of the convection, viscous sublayer, and turbulence closure schemes  

SciTech Connect

The step-mountain eta model has shown a surprising skill in forecasting severe storms. Much of the credit for this should be given to the Betts and Miller (hereafter referred to as BM) convection scheme and the Mellor-Yamada (hereafter referred to as MY) planetary boundary layer (PBL) formulation. However, the eta model was occasionally producing heavy spurious precipitation over warm water, as well as widely spread light precipitation over oceans. In addition, the convective forcing, particularly the shallow one, could lead to negative entropy changes. As the possible causes of the problems, the convection scheme, the processes at the air-water interface, and the MY level 2 and level 2.5 PBL schemes were reexamined. A major revision of the BM scheme was made, a new marine viscous sublayer scheme was designed, and the MY schemes were returned. The MY level 2.5 turbulent kinetic energy (TKE) is initialized from above in the PBL, so that excessive TKE is dissipated at most places during the PBL spinup. The method for calculating the MY level 2.5 master length scale was rectified. To demonstrate the effects of the new schemes for the deep convection and the viscous sublayer, tests were made using two summer cases: one with heavy spurious precipitation, and another with a successful 36-h forecast of a tropical storm. The new schemes had dramatic positive impacts on the case with the spurious precipitation. The results were also favorable in the tropical storm case. The developments presented here were incorporated into the eta model in 1990. The details of further research will be reported elsewhere. The eta model became operational at the National Meteorological Center, Washington, D.C., in June 1993. 60 refs., 8 figs.

Janjic, Z.I. (Univ. Corporation for Atmospheric Research, Washington, DC (United States))

1994-05-01

138

The role of moist convection in the West African monsoon system: Insights from continental-scale convection-permitting simulations  

NASA Astrophysics Data System (ADS)

Predicting the West African monsoon (WAM) remains a major challenge for weather and climate models. We compare multiday continental-scale simulations of the WAM that explicitly resolve moist convection with simulations which parameterize convection. Simulations with the same grid spacing but differing representations of convection isolate the impact of the representation of convection. The more realistic explicit convection gives greater latent and radiative heating farther north, with latent heating later in the day. This weakens the Sahel-Sahara pressure gradient and the monsoon flow, delaying its diurnal cycle and changing interactions between the monsoon and boundary layer convection. In explicit runs, cold storm outflows provide a significant component of the monsoon flux. In an operational global model, biases resemble those in our parameterized case. Improved parameterizations of convection that better capture storm structures, their diurnal cycle, and rainfall intensities will therefore substantially improve predictions of the WAM and coupled aspects of the Earth system.

Marsham, John H.; Dixon, Nick S.; Garcia-Carreras, Luis; Lister, Grenville M. S.; Parker, Douglas J.; Knippertz, Peter; Birch, Cathryn E.

2013-05-01

139

A comparison of stratosphere-troposphere transport in convection-permitting and convection-parameterizing simulations of three mesoscale convective systems  

Microsoft Academic Search

The transport of stratospheric air into the troposphere within deep convection was investigated using the Met Office Unified Model version 6.1. Three cases were simulated in which convective systems formed over the UK in the summer of 2005. For each of these three cases, simulations were performed on a grid having 4 km horizontal grid spacing in which the convection

Jeffrey M. Chagnon; Suzanne L. Gray

2010-01-01

140

Regional analysis of convective systems during the West African monsoon  

NASA Astrophysics Data System (ADS)

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 characteristics (e.g. total precipitation and vertical reflectivity profiles) at the inland and maritime sites. The wave regime also resulted in an increased population of the largest observed mesoscale convective systems observed near the coast, which led to an increase in stratiform precipitation. Despite this increase, differentiation of convective strength characteristics was less obvious between wave and no-wave regimes at the coast. Due to the propagating nature of these advecting mesoscale convective systems, interaction with the regional thermodynamic and dynamic environment appears to result in more variability than enhancements due to the wave regime, independent of location. A 13-year (1998-2010) climatology of mesoscale convective characteristics associated with the West African monsoon are also investigated using precipitation radar and passive microwave data from the NASA Tropical Rainfall Measuring Mission satellite. Seven regions defined as continental northeast and northwest, southeast and southwest, coastal, and maritime north and south are compared to analyze zonal and meridional differences. Data are categorized according to identified African easterly wave (AEW) phase and when no wave is present. While some enhancements are observed in association with AEW regimes, regional differences were generally more apparent than wave vs. no-wave differences. Convective intensity metrics confirm that land-based systems exhibit stronger characteristics, such as higher storm top and maximum 30-dBZ heights and significant 85-GHz brightness temperature depressions. Continental systems also contain a lower fraction of points identified as stratiform. Results suggest that precipitation processes also varied depending upon region and AEW regime, with warm-rain processes more apparent over the ocean and the southwest continental region and ice-based microphysics more dominant over land, including mixed-phase processes. AEW regimes did show variability in stratiform fraction and ice and liquid water content, suggesting modulation of mesoscale characteristics possibly throug

Guy, Bradley Nicholas

141

Thermospheric neutral wind response to geomagnetic storms  

NASA Astrophysics Data System (ADS)

The CISM Coupled Magnetosphere-Ionosphere-Thermosphere (CMIT) model, which includes two-way coupling between the Thermosphere/Ionosphere Nested Grid (TING) Model and the Lyon-Fedder-Mobarry (LFM) global magnetosphere MHD code, is run to investigate the near Earth space weather response to the 12-15 May 1997 geomagnetic storm. In this paper we will focus on the high and middle latitudes thermospheric wind variations during the storm. Two major processes change the storm time neutral wind circulation: an enhanced ion drag effect that forces the neutrals to follow the expanded ion convective drift, and an intensified Joule heating effect that increases the high latitude pressure gradient and thus changes the global wind pattern. We will discuss temporal and spatial evolutions of neutral wind changes after the storm commencement, and the time cadence of neutral wind recovery after the storm. Of particular interest to this study is a jet of neutral winds that occurs in the middle latitudes during the storm.

Wang, W.; Burns, A. G.; Wiltberger, M.; Solomon, S. C.; Killeen, T. L.; Lyon, J. G.; Goodrich, C.

2005-05-01

142

Summer Astronomy  

ERIC Educational Resources Information Center

|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…

Riddle, Bob

2004-01-01

143

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

NASA Astrophysics Data System (ADS)

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 the comparison of seeded and unseeded convective cells and on documented hail information from the ground.

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

2013-04-01

144

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

NASA Astrophysics Data System (ADS)

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 evolution of predefined multiple thresholds in graphical form for any selected location. With applying this tool degree of the dangerous weather conditions can be well estimated. Besides intensive convective periods are clearly marked during the forecasting period. Developments were done by MAGICS++ software under UNIX operating system. The third part of the study usefulness of these tools is demonstrated in three interesting cases studies of last summer.

Lazar, Dora; Ihasz, Istvan

2013-04-01

145

Magnetic storms as a human infarction hazard: season effects  

NASA Astrophysics Data System (ADS)

There are a great number of clinical and statistical studies confirming that the myocardial infarction number rises during geomagnetic disturbances, which have a maximum of occurrence near equinox. Contrary to that, the analysis of the daily numbers of Moscow ambulance calls (1979-1981), related to the myocardial infarction, showed the strong winter maximum and summer minimum. The similar result we obtained by using the 25 year data (1970-1995) on the death from infarction in Bulgaria. We analyzed the biotropic efficacy of 129 geomagnetic storms and found that its hazard depends on the season. About of 90% of the winter time magnetic storms were accompanied by the infarction enhancement, but only ~ 3% of the summer magnetic storms led to the increasing of the cardiac problems. It means that the human organism stability to the "negative" influence of magnetic storms is stronger in summer than in winter. We also found that the different magnetic storm phases demonstrate the different hazard. As a rule, the storm main phase was not accompanied by the enhancement of the infarction number. However, the storm recovery phase typically leads to infarction increasing, particularly, if it was accompanied by the geomagnetic pulsation at periods of a few seconds.

Kleimenova, N.; Kozyreva, O.

2009-04-01

146

Summer Reading  

NASA Astrophysics Data System (ADS)

Summer, a great time for leisure reading, a great time to try something different! Dick Pagni, Cheryl Frech, Brian Coppola, Jeffrey Kovac, and Hal Harris provide plenty of suggestions to keep you reading!

Pagni, Dick; Frech, Cheryl; Coppola, Brian; Kovac, Jeffrey; Harris, Hal

2007-06-01

147

Saturn lightning storms and their implications on Saturn's atmosphere  

NASA Astrophysics Data System (ADS)

Thunderstorms in Saturn's atmosphere are intermittent, lasting for a few days to several months. The storms can be observed by ground-based optical telescopes, and several instruments aboard the Cassini spacecraft deliver valuable information about them. The Radio and Plasma Wave Science (RPWS) instrument records strong radio waves from Saturn lightning termed Saturn Electrostatic Discharges (SEDs). Lightning is a good indicator of vertical convection, and the visible plumes are high-altitude clouds that overshoot the outermost ammonia cloud layer, transporting cloud particles as well as particles produced by the lightning itself to levels above 1 bar. In December 2010 the most powerful thunderstorm of the Cassini era emerged in the northern hemisphere at a latitude of 35° north with flash rates about an order of magnitude higher compared to previous SED storms. The storm reached a latitudinal extension of ~10,000 km within 3 weeks after its start, much larger than previous thunderstorms that were ~2000 km in size and observed at a latitude of 35° south. The storm developed an elongated eastward tail that encircled the whole planet by February 2011. The main SED storm cell resided in the head of the storm, but continuously broadened in longitude with time. The switch in hemispheres of the lightning storms reveals a possible seasonal influence since Saturn experienced vernal equinox in August 2009. An estimation of the power of the storm revealed quantities comparable to Saturn's total emitted power. Hence, giant storms like this might be a significant term in the internal heat budget.

Fischer, G.; Kurth, W. S.; Gurnett, D. A.; Zarka, P.; Dyudina, U. A.; Ingersoll, A. P.; Ewald, S. P.; Porco, C. C.; Wesley, A.; Go, C.; Delcroix, M.

2011-10-01

148

Ionospheric storm time dynamics as seen by GPS tomography and in situ spacecraft observations  

Microsoft Academic Search

During major geomagnetic storms anomalous enhancements of the ionospheric density are seen at high and middle latitudes. A number of physical mechanisms have been invoked to explain these storm time density anomalies including an expansion of high-latitude electric plasma convection to midlatitudes, thermospheric neutral winds, and changes in the ionospheric composition. However, it remains unclear which mechanism plays the dominant

D. Pokhotelov; C. N. Mitchell; P. S. J. Spencer; M. R. Hairston; R. A. Heelis

2008-01-01

149

Simulation of electrified storms with comparison of the charge structure and lightning efficiency  

Microsoft Academic Search

An electrification and lightning flash scheme was run in a cloud-resolving model to study the electrical structure of idealized convective storms with several charge separation parameterizations. The electrification of an intense multicellular storm was first simulated. The results confirm the sensitivity of the cloud polarity and lightning flash characteristics to three noninductive charging formulations. Furthermore, it is found that the

Christelle Barthe; Jean-Pierre Pinty

2007-01-01

150

Statistical comparison of interplanetary conditions causing intense geomagnetic storms (Dst ? ?100 nT)  

Microsoft Academic Search

It is well known that intense southward magnetic field and convection electric field (V × B) in the interplanetary medium are key parameters that control the magnitude of geomagnetic storms. By investigating the interplanetary conditions of 82 intense geomagnetic storms from 1998 to 2006, we have compared many different criteria of interplanetary conditions for the occurrence of the intense geomagnetic

Eun-Young Ji; Y.-J. Moon; K.-H. Kim; D.-H. Lee

2010-01-01

151

Balanced Storm Drainage (Storm Drains for Roadways).  

National Technical Information Service (NTIS)

Model tests based on the system in use by the Kansas State Highway Commission were conducted at a scale of 1:3 to provide additional information on the flow of storm water in street gutters and its interception by storm drains. The significant factors stu...

J. S. McNown C. H. Tai

1971-01-01

152

Exploring Hurricane Storm Surge  

NSDL National Science Digital Library

Hurricanes cause damage in three ways: wind, rain, and storm surge. This project explores the causes and effects of storm surge in hurricanes. While wind and rain are two of the most obvious effects of hurricanes, storm surge can be one of the most destructive. This project involves using the resources from the NSDL to understand why storm surge occurs, where it occurs, and what governs how bad it can be. Start by reading ...

Dean

2006-05-15

153

Aircraft icing at low temperatures in Tropical Storm Chantal (2001)  

Microsoft Academic Search

Recent in situ measurements of water vapor, meteorological properties, and cloud particles provide evidence for large slushy ice particles at ?40°C in an intense tropical updraft. During a flight through Tropical Storm Chantal (20 Aug. 2001), the NASA DC-8 aircraft encountered strong convection, high humidities, high particle concentrations, and plugged probe inlets. This paper addresses the question of whether these

Robert L. Herman; Andrew J. Heymsfield

2003-01-01

154

Properties of singular vectors using convective available potential energy as final time norm  

NASA Astrophysics Data System (ADS)

We study the feasibility of using the singular vector technique to create initial condition perturbations for short-range ensemble prediction systems (SREPS) focussing on predictability of severe local storms and in particular deep convection. For this a new final time semi-norm based on the convective available potential energy (CAPE) is introduced. We compare singular vectors using the CAPE-norm with SVs using the more common total energy (TE) norm for a 2-week summer period in 2007, which includes a case of mesoscale extreme rainfall in the south west of Finland. The CAPE singular vectors perturb the CAPE field by increasing the specific humidity and temperature of the parcel and increase the lapse rate above the parcel in the lower troposphere consistent with physical considerations. The CAPE-SVs are situated in the lower troposphere. This in contrast to TE-SVs with short optimization times which predominantly remain in the high troposphere. By examining the time evolution of the CAPE singular values we observe that the convective event in the south west of Finland is clearly associated with high CAPE singular values.

Stappers, Roel; Barkmeijer, Jan

2011-05-01

155

Summer Days.  

ERIC Educational Resources Information Center

In response to regular faculty complaints about mainstreamed students, a 5-week Summer Special Education Program was implemented in 1986 at the Western Navajo Agency's Tuba City Boarding School. The program's purpose was to train regular teachers and support personnel in special education procedures and practices and to provide the exceptional…

Foster, Carl; Beeman, Sandi

156

Summer Skies  

ERIC Educational Resources Information Center

|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…

Science Scope, 2005

2005-01-01

157

Summer Camp.  

ERIC Educational Resources Information Center

|Government regulation of children's summer camps, particularly involving health and safety standards, is discussed in a series of brief interviews with camp directors and representatives of camp associations. Transcribed from the National Public Radio weekly broadcast, "Options in Education," the program includes a lengthy montage of children's…

Burns, Maxine; And Others

158

Meteorological indicators of summer precipitation chemistry in central Pennsylvania  

NASA Astrophysics Data System (ADS)

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 instability.

Dayan, Uri; Lamb, Dennis

159

Spatial storm statistics  

NASA Astrophysics Data System (ADS)

The classical approach to storm statistics in the ocean is an Eulerian analysis of wave time series at a given location, in which the wave data can be observations or results of wave models. The information obtained from this approach is storm frequency, duration and intensity, from which extremes only at the particular location can be estimated. The availability of spatial information of wave characteristics at successive time intervals, which is available from large scale hindcast allows the follow-up of storm evolution in space and time. Using this data it is possible to study the spatial evolution of storms, i.e. to provide a Lagrangean description of storm characteristics. Ships cross the ocean in the routes that are chosen in order to minimize danger and expenses. A safer route will try to avoid high seas and areas with high probability of storms. In the Eulerian approach information about the storm spatial and temporal evolution is not available. In the Lagrangean approach a storm is defined as spatial pulse above the defined threshold z, which is moving over the basin. The area defined by the set of contiguous points is the storm area in any moment. It is possible to obtain the geometrical center of the storm, it square, speed of movement, the maximum significant wave heights (SWH), the coordinates of the maximum SWH values, and some other statistics. The details of approaches and results for some Seas and N. Atlantic will be presented.

Lopatoukhin, Leonid; Boukhanovsky, Alexander; Chernysheva, Ekaterina

2013-04-01

160

Effect of storm type on rainwater composition in southeastern North Carolina  

SciTech Connect

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.

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

1988-01-01

161

The Vertical Distribution of Dust in the Martian Atmosphere: The Haze in the Clear Season and the Haze After the Storm  

NASA Astrophysics Data System (ADS)

Observations by the Mars Climate Sounder (MCS) over the last two martian years have permitted the creation of pressure-pegged retrievals of temperature, dust opacity, and water ice opacity at a vertical resolution of approximately 5 km. These retrievals provide information about the vertical distribution of dust and water ice over a wide dynamic range of mass mixing ratio and/or aerosol heating rate. Thus, MCS retrievals can powerfully complement observations by nadir-looking instruments on Mars Reconnaissance Orbiter or surface landers. For whereas nadir-looking instruments are most sensitive to order unity cloud cover near the surface, MCS limb retrievals are most sensitive to the sub-visible hazes farther above the surface. In this presentation, we will discuss two broad types of dust haze we have identified in MCS retrievals and their significance for dust lifting, transport, and removal processes in the martian atmosphere. In late northern spring and early northern summer, the dust mass mixing ratio profile in the tropics appears to have a significant maximum between 15 and 25 km above the local surface, “the high altitude tropical dust maximum.” While water ice condensation on dust particles and orographically-driven dust lifting may play some role in driving this distribution, we have argued that its primary driver is more likely to be a process akin to moist convection in which shortwave heating of dust in Mars’s thin atmosphere has very similar effects to the latent heat released by condensing water vapor in the Earth’s atmosphere. This type of haze is associated with low column dust opacities throughout the latitudinal band in which it occurs. The other type of haze is associated with the much higher column opacities attributed to dust storm activity. We will present examples from north polar cap edge dust storm activity in northern spring, early season tropical dust storm activity in the middle of northern summer, and the global dust storm of 2007. The latter two events produced hazes with dust mass mixing ratio maxima of greater magnitude and at higher altitude than the high altitude tropical dust maximum, which are consonant with hazes observed by MGS/TES during the 2001 global dust storm. These observations raise the question of whether the second type of dust haze could be driven by a larger-scale version of the pseudo-moist convection we have proposed to explain the first.

Heavens, N. G.; Richardson, M. I.; Kleinboehl, A.; Kass, D.; McCleese, D. J.; Mars Climate Sounder Science Team

2010-12-01

162

Storms on the Sun  

Microsoft Academic Search

\\u000a Solar flares and coronal mass ejections are the most important storm phenomena in the atmosphere of the Sun. The observation\\u000a that a geomagnetic storm commenced only some 17 hours after the flare observed by Carrington and Hodgson in 1859, and many\\u000a subsequent events suggesting a similar flare–storm relationship, led to the hypothesis that the flares were the drivers of\\u000a the

Hannu E. J. Koskinen

163

On the seasonal response of the thermosphere and ionosphere to geomagnetic storms  

Microsoft Academic Search

Ionosonde observations have provided the data to build a picture of the response of the midlatitude ionosphere to a geomagnetic storm. The particular characteristic of interest is the preference for ``negative storms'' (decrease in the peak electron density, NmF2) in summer and ``positive storms'' (increase in NmF2) in winter. A three-dimensional, time-dependent model of the coupled thermosphere and ionosphere is

T. J. Fuller-Rowell; M. V. Codrescu; H. Risbeth; R. J. Moffett; S. Quegan

1996-01-01

164

The Impacts of Chihuahua Desert Aerosol Intrusions on Convective Clouds and Regional Precipitation  

NASA Astrophysics Data System (ADS)

Growing up in a desert region influenced by a monsoon system and experiencing, first-hand, dust storms produced by convective thunderstorms stimulated my interest in the study of the impacts of aerosols on clouds. Contrary to other studies which focus more on anthropogenic aerosols, I chose to investigate the role of natural aerosols in the deserts of North America. Moreover, the role played by aerosols in desert regions within the North American Monsoon domain has not received as much attention as in other monsoon regions around the world. This dissertation describes my investigation of the connection between mineral aerosols (dust storms) and monsoon rainfall in the deserts of the Southwestern United States and Northwestern Mexico. To develop the context for the study of the role of mineral dust in summer-time convection on a regional scale, large-scale dynamical processes and their impact on the inter-annual variability of monsoon rainfall were analyzed. I developed the climatology of monsoonal rainfall and dust storms using surface observations to determine which mesoscale features influence North American Monsoon rainfall in the Paso Del Norte region. The strongest correlations were found between sea surface temperatures over the Gulf of California, Gulf of California moisture surges and monsoon rainfall in the Paso Del Norte region. A connection to ENSO could not be clearly established despite analyzing twenty-one years of data. However, by breaking the data into segments, a strong correlation was found for periods of intense rainfall. Twenty-one case studies were identified in which dust storms were produced in conjunction with thunderstorms during the 2005 - 2007 monsoon seasons. However, in some cases all the conditions were there for rainfall to occur but it did not precipitate. I concluded that strong thunderstorm outflow was triggering dust storms. The Weather Research and Forecasting model coupled with Chemistry (WRF-Chem V3.1.1) was used to evaluate the model's sensitivity to the inclusion of aerosol effects on cloud drop formation and on direct radiative forcing. A comparison of the relative contribution of aerosol direct and indirect forcings in terms of differences in aerosol and cloud optical thicknesses, cloud water content, cloud droplet number, and short wave and long wave radiation, revealed that cloud cover is reduced. This suggests that Chihuahua desert dust affects cloud formation.

Apodaca, Karina

165

Tropical Storms, Worldwide  

NSDL National Science Digital Library

The University of Hawaii's Mees Solar Observatory, stationed at Haleakala, Maui, provides a wealth of data and images in its Webpages. This page, Tropical Storms Worldwide, gives regional maps and written updates of hurricane, typhoon, and tropical cyclone activity around the globe. The page also features a strike probability calculator where users click on a list of geographic locations or enter map coordinates or a US zip code in order to view the probability of a tropical storm reaching that area. A storm data archive (1994-2000) and printer-friendly .pdf-formatted storm track maps are also available.

1996-01-01

166

Simulating Dust Storms on Mars with Variable Surface Dust Abundance and Particle Size Distributions  

Microsoft Academic Search

To date, no numerical model of the martian atmosphere has fully captured the range and variability of the large dust storms that occur during southern spring and summer. A major difficulty is properly estimating the abundance and size distribution of sand and dust on the surface and how this varies with time. Storm onset should occur in regions where BOTH

Claire E. Newman; C. Lee; Y. Lian; M. I. Richardson; A. D. Toigo

2010-01-01

167

The Role of Ice Phase Microphysics in Aerosol Convection Interactions  

NASA Astrophysics Data System (ADS)

The effect of aerosols on clouds has been studied fairly extensively for warm clouds, but less so for deep convective storms. The addition of the ice phase in these clouds and the more numerous microphysical processes that play a role in producing precipitation lead to a much more complex response of deep convective processes to the presence of enhanced aerosol concentrations. However, large amounts of precipitation can be produced in deep convective storms, making it especially important to understand the precipitation response to aerosols. Typically, studies investigating the response of clouds to increased aerosols have found that clouds forming in environments with more aerosols available to act as cloud condensation nuclei (ccn) have a less efficient warm rain process due to the narrower cloud droplet spectrum created by the nucleation of large numbers of cloud drops. However, the total precipitation produced by deep convective storms has sometimes been found to increase with aerosol concentration, counter to what is often found in warm clouds. This suggests that different mechanisms may be important, related to interactions with ice in these clouds. Possibly the amount of rain formed from melted graupel and hail is enhanced, or the storms undergo convective invigoration due to the larger latent heat released in the freezing of more supercooled droplets. The goal of this project is to investigate the effects that enhanced aerosol concentrations can have on deep convective storms. This will be accomplished using large-scale two-dimensional long-term simulations of the tropics that have been run in a radiative-convective equilibrium framework. These simulations only vary in the number of aerosols available to act as ccn, and offer a large sample of deep convective profiles to examine statistically. The model being used is the Regional Atmospheric Modeling System (RAMS), which allows for the ccn number concentrations to be prognosed based on background aerosol concentration and environmental conditions. Initial results from the RCE simulations show that convection that forms in an environment with more aerosols available to act as ccn does not show evidence of stronger updrafts, contrary to many studies that have found convective invigoration to be the case. Examining the microphysical budgeting terms available in the model will allow for increased understanding of which processes (i.e. freezing and melting of different species, riming, aggregation, etc.) contribute to this result. Findings from the large-domain RCE simulations will be compared with high resolution, three-dimensional single cloud simulations of deep convective storms in polluted environments. Results will be presented showing the relevant microphysical processes that are affected by changing aerosol concentrations, in an attempt to explain how the presence of the ice phase affects the convective cloud response to high aerosol concentrations.

Storer, R. L.; van den Heever, S. C.

2011-12-01

168

Magnetospheric Convection.  

National Technical Information Service (NTIS)

Magnetospheric convection, which implies the existence of large-scale electric fields, appears to be the dominant process for the acceleration and injection of moderately energetic plasma into the magnetosphere. The aurora, the radiation belts, and the 't...

W. I. Axford

1969-01-01

169

Unusual Winter Storm, Hawaii.  

National Technical Information Service (NTIS)

From January 8 to 11, 1980, the Hawaiian Islands experienced some of the most severe weather from a winter storm in recent years. Even though rainfall was over 20 inches in some places, the most noteworthy and damaging aspects of this storm episode were t...

H. E. Rosendal

1980-01-01

170

STORM WATER MANAGEMENT MODEL  

EPA Science Inventory

Storm Water Management Model (SWMM) is a comprehensive model for analysis of quantity and quality problems associated with urban runoff. Both single-event and continuous simulation may be performed on catchments having storm sewers, combined sewers, and natural drainage, for pred...

171

Dust storms in Turkmenistan  

Microsoft Academic Search

Dust storms are a phenomenon particularly common to the arid and semi-arid regions of Turkmenistan. The aridity of the climate, vast areas of sandy, solonchak and clayey deserts, sparse vegetation cover, and strong winds all favor the formation of dust storms. Long-term (60 years) data from 56 meteorological stations was analysed for the study of spatial distribution, frequency, seasonality and

L. Orlovsky; N. Orlovsky; A. Durdyev

2005-01-01

172

Prompt penetration electric fields (PPEFs) and their ionospheric effects during the great magnetic storm of 30–31 October 2003  

Microsoft Academic Search

We explore the ionospheric effects of prompt penetration electric fields (PPEFs) for a variety of interplanetary magnetic field directions. We use the great magnetic storm of 30–31 October as an example of PPEF effects. For intense southward interplanetary magnetic fields (IMFs), inward plasma sheet convection occurs with the result of magnetospheric ring current formation and an intense magnetic storm. Concurrent

B. T. Tsurutani; O. P. Verkhoglyadova; A. J. Mannucci; A. Saito; T. Araki; K. Yumoto; T. Tsuda; M. A. Abdu; J. H. A. Sobral; W. D. Gonzalez; H. McCreadie; G. S. Lakhina; V. M. Vasyli?nas

2008-01-01

173

Prompt penetration electric fields (PPEFs) and their ionospheric effects during the great magnetic storm of 30-31 October 2003  

Microsoft Academic Search

We explore the ionospheric effects of prompt penetration electric fields (PPEFs) for a variety of interplanetary magnetic field directions. We use the great magnetic storm of 30-31 October as an example of PPEF effects. For intense southward interplanetary magnetic fields (IMFs), inward plasma sheet convection occurs with the result of magnetospheric ring current formation and an intense magnetic storm. Concurrent

B. T. Tsurutani; O. P. Verkhoglyadova; A. J. Mannucci; A. Saito; T. Araki; K. Yumoto; T. Tsuda; M. A. Abdu; W. D. Gonzalez; H. McCreadie; G. S. Lakhina; V. M. Vasyliunas

2008-01-01

174

Ionospheric Storms — A Review  

NASA Astrophysics Data System (ADS)

In this paper, our current understanding and recent advances in the study of ionospheric storms is reviewed, with emphasis on the F2-region. Ionospheric storms represent an extreme form of space weather with important effects on ground- and space-based technological systems. These phenomena are driven by highly variable solar and magnetospheric energy inputs to the Earth's upper atmosphere, which continue to provide a major difficulty for attempts now being made to simulate the detailed storm response of the coupled neutral and ionized upper atmospheric constituents using increasingly sophisticated global first principle physical models. Several major programs for coordinated theoretical and experimental study of these storms are now underway. These are beginning to bear fruit in the form of improved physical understanding and prediction of ionospheric storm effects at high, middle, and low latitude.

Buonsanto, M. J.

1999-04-01

175

New insights on geomagnetic storms from observations and modeling  

SciTech Connect

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.

Jordanova, Vania K [Los Alamos National Laboratory

2009-01-01

176

Intensification of Pacific storm track linked to Asian pollution  

PubMed Central

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 intensifed 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.

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

2007-01-01

177

Ionospheric storm time dynamics as seen by GPS tomography and in situ spacecraft observations  

NASA Astrophysics Data System (ADS)

During major geomagnetic storms anomalous enhancements of the ionospheric density are seen at high and middle latitudes. A number of physical mechanisms have been invoked to explain these storm time density anomalies including an expansion of high-latitude electric plasma convection to midlatitudes, thermospheric neutral winds, and changes in the ionospheric composition. However, it remains unclear which mechanism plays the dominant role in the formation of storm time density anomalies, partly because of insufficient coverage of the measurements of global electric convection and thermospheric winds at midlatitudes. This paper describes a novel technique for extracting the storm time E × B convection boundary from in situ measurements of plasma bulk motion obtained by LEO DMSP satellites. The convection boundary estimated from the DMSP data during major magnetic storm of 20 November 2003 has been compared with the global distributions of the ionospheric plasma deduced from characteristics of GPS signals acquired by a ground-based network of GPS receivers. The tomographic inversion of GPS data using a three-dimensional time-dependent inversion technique reveals the spatial and temporal evolution of the storm time density anomaly. Comparison between the tomographic reconstructions of the ionospheric plasma distributions and in situ DMSP measurements of plasma bulk motion suggests that the convective flow expanded low enough in latitude to encompass, in part, the formation of the midlatitude TEC anomaly. Some features of the TEC dynamics observed during the 20 November 2003 storm, however, suggest that mechanisms other than the expanded ionospheric convection (such as thermospheric neutral winds) are also involved in the formation of the midlatitude anomaly.

Pokhotelov, D.; Mitchell, C. N.; Spencer, P. S. J.; Hairston, M. R.; Heelis, R. A.

2008-03-01

178

‘RCHX-1STORM’ first Slovenian meteorological rocket program  

Microsoft Academic Search

Astronautic and Rocket Society Celje (ARSC) formed a special working team for research and development of a small meteorological hail suppression rocket in the 70th. The hail suppression system was established in former Yugoslavia in the late 60th as an attempt to protect important agricultural regions from one of the summer's most vicious storm. In this time Slovenia was a

Aleksander Kerstein; Drago Matko; Amalija Trauner; Zvone Britovšek

2004-01-01

179

Investigation of aerosol indirect effects on simulated moist convections using the double-moment bulk microphysics scheme  

NASA Astrophysics Data System (ADS)

Aerosols indirect effects on simulated moist convections have been investigated with the bulk-type WDM6 microphysics scheme (Lim and Hong 2010). The impact of the aerosol concentration on the simulated storm was evaluated by varying the initial CCN number concentration in the WDM6 microphysics scheme. We have tested several moist convection cases such as idealized squall line, supercell storm, and 3D-moist real convection system and analyzed the aerosol indirect effects focusing on the storm development and surface precipitation. Furthermore, we have proposed the refined treatment of a cumulus parameterization scheme to establish a comprehensive understanding of aerosol indirect effects on the globe.

Lim, K.-S. S.; Hong, S.-Y.

2012-04-01

180

Dust storms: recent developments.  

PubMed

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. PMID:18783869

Goudie, Andrew S

2008-09-09

181

Disaggregating convective and stratiform precipitation from station weather data  

NASA Astrophysics Data System (ADS)

We propose an alternative algorithm for disaggregating precipitation amounts into predominantly convective and stratiform based on station weather data. The algorithm is tested at 11 stations in the Czech Republic over 1982-2010, and climatological characteristics and trends of convective and stratiform precipitation are analysed. The results show that, while convective precipitation has a sharp annual cycle, stratiform precipitation is relatively constant throughout the year and does not contribute to the annual cycle of total precipitation. Dependence of precipitation amounts on altitude is stronger for stratiform than convective precipitation consistently across all seasons. The proportion of convective precipitation sharply increases with rising daily temperature in summer, but an analogous relationship is much weaker at the seasonal time scale. Trends in convective precipitation were rising over 1982-2010 in all three seasons in which convective precipitation is important (spring, summer and autumn) and they are stronger than are trends in stratiform precipitation in each season. This shows that the observed increases in total precipitation are mainly due to increases in convective precipitation, and this effect may also be related to an observed warming of surface air temperatures that may enhance instability and support conditions for stronger convection. The resulting time series of convective and stratiform precipitation may have several further applications, including for analysing probability distributions of extremes and evaluating climate models that simulate convective and stratiform precipitation through different parameterizations.

Rulfová, Zuzana; Kyselý, Jan

2013-12-01

182

Cross-tropopause tracer transport in midlatitude convection  

Microsoft Academic Search

A three-dimensional cloud-resolving model is used to simulate the transport of lower-tropospheric passive tracers into the lowermost stratosphere via midlatitude convection. In previous studies of troposphere-to-stratosphere convective transport the extent of irreversible transport is unclear because the tropopause location is difficult to determine in the highly perturbed environment directly above an active storm. To determine the irreversibility of cross-tropopause transport

G. L. Mullendore; D. R. Durran; J. R. Holton

2005-01-01

183

Thyrotoxicosis and thyroid storm.  

PubMed

Thyroid storm represents the extreme manifestation of thyrotoxicosis as a true endocrine emergency. Although Grave's disease is the most common underlying disorder in thyroid storm, there is usually a precipitating event or condition that transform the patient into life-threatening thyrotoxicosis. Treatment of thyroid storm involves decreasing new hormone synthesis, inhibiting the release of thyroid hormone, and blocking the peripheral effects of thyroid hormone. This multidrug, therapeutic approach uses thionamides, iodine, beta-adrenergic receptor antagonists, corticosteroids in certain circumstances, and supportive therapy. Certain conditions may warrant the use of alternative therapy with cholestyramine, lithium carbonate, or potassium perchlorate. After the critical illness of thyroid storm subsides, definitive treatment of the underlying thyrotoxicosis can be planned. PMID:17127140

Nayak, Bindu; Burman, Kenneth

2006-12-01

184

Indian Summer  

SciTech Connect

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.

Galindo, E. [Sho-Ban High School, Fort Hall, ID (United States)

1997-08-01

185

Predicting lightning storms  

NASA Astrophysics Data System (ADS)

Lightning is the second most deadly weather phenomenon after flash floods. It kills more people a year than tornadoes and damages utilities, curtails recreational activities, and affects flight paths. Roughly half of all aviation accidents are weather related according to Delain Edman, of the National Weather Service's National Severe Storms Forecast Center, Kansas City, Mo. That's why meteorologists are testing a new lightning detection network to help predict storms and pinpoint “hot spots” of lightning activity.

Wainger, Lisa A.

186

Ionospheric Storms — A Review  

Microsoft Academic Search

In this paper, our current understanding and recent advances in the study of ionospheric storms is reviewed, with emphasis\\u000a on the F2-region. Ionospheric storms represent an extreme form of space weather with important effects on ground- and space-based\\u000a technological systems. These phenomena are driven by highly variable solar and magnetospheric energy inputs to the Earth's\\u000a upper atmosphere, which continue to

M. J. Buonsanto

1999-01-01

187

Evaluating Forecasts of Central US Mesoscale Convective Systems in a GCM with Explicit Embedded Convection  

NASA Astrophysics Data System (ADS)

Recent work has demonstrated that the Central US organized nocturnal eastward propagating mode of convection can be captured in a prototype global climate model (GCM) which uses embedded cloud resolving models (CRM) instead of statistical parameterizations to handle sub-grid convection (superparameterization - SPCAM). This is a surprising result since the CRM in SPCAM is idealized in two dimensions with periodic boundary conditions, which restricts fast manifold storm propagation mechanisms to the horizontal scale of a GCM grid box and constrains CRM shear organization to a fixed horizontal plane. Nonetheless, these simulated storms have been qualitatively characterized as having realistic propagation speeds, and have been argued to result from slow manifold pathways linking large-scale dynamics with a prognostic convective lifecycle (CRM memory). However, rigidities in the technique (fixed CRM orientation) and apparent discrepancies in the simulated storm relative flow structure are unresolved issues requiring closer analysis. The Cloud-Associated Parameterizations Testbed (CAPT) approach to evaluating GCM error statistics in forecast mode is applied here to test the sensitivity of this result to CRM orientation and to quantitively compare against observed storm systems that passed over high value ground based sensors at the ARM SGP site. A Newtonian relaxation "nudging" technique has been developed to initialize both resolved scales in SPCAM (GCM and 2D CRM) for forecast simulations, spinning up the CRM by forcing the outer model to follow analyzed observations. Propagating storms are captured in SPCAM with zonal, meridional, and southeast CRM orientations, but comparisons to observations reveal many features of the storm location, thermodynamic structure, and condensate fields to be overly simulated or mispositioned.

Kooperman, G. J.; Pritchard, M. S.; Somerville, R. C.; Khairoutdinov, M.

2011-12-01

188

Convection towers  

DOEpatents

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.

Prueitt, M.L.

1996-01-16

189

Convection towers  

DOEpatents

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.

Prueitt, Melvin L. (Los Alamos, NM)

1994-01-01

190

Modeling Convection  

ERIC Educational Resources Information Center

|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…

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

2004-01-01

191

Thermobaric Convection.  

National Technical Information Service (NTIS)

Large-eddy simulation of two cases of free convection in the polar seas reveal the three dimensional structure of thermobaric-enhanced turbulence, with and without salinity stratification. In the first case, with no initial stratification, 3.6 km deep fre...

R. W. Garwood S. M. Isakari P. C. Gallachar

1993-01-01

192

Convection affection  

Microsoft Academic Search

Convection ovens continue to attract — and confuse — cooks. Do they work onl y for baking ? Why does cooking faster matter? According to Amy Ahrens- dorf, chef for SunWest Appliance Distributing in Te mpe, Ariz., convec- tion ovens are all-purpose kitchen workhorses, turning out evenly cooked cookies; juicy, well-browned poultry and meats; and vegetables packed with caramelized flavor.

KAREN FERNAU; Anjanette Rieger; Jerrold Simon; Ryan Glenn

2007-01-01

193

Convection Current  

NSDL National Science Digital Library

In this activity, learners make their own heat waves in an aquarium. Warmer water rising through cooler water creates turbulence effects that bend light, allowing you to project swirling shadows onto a screen. Use this demonstration to show convection currents in water as well as light refraction in a simple, visually appealing way.

Exploratorium, The

2012-06-26

194

Super Tuesday storm variability  

NASA Astrophysics Data System (ADS)

At least ten supercell storms moved within 130 km of WSR-88D radars during the Super Tuesday outbreak of 5-6 February 2008 so that a detailed study of both reflectivity and velocity over sufficiently long time periods could be performed. The variability of these fields in relation to other storms in the outbreak, relative time in the outbreak and occurrence of tornadoes (if any) is closely examined. Observations of possible atmospheric wave and topography interactions with the storms will also be presented. Two supercells passed within 30-40 km of radar sites (KNQA and KOHX). The relative steadiness of these storms during passage, along with the large motion vector (from the southwest at 20-25 m/s), allowed the application of a synthetic dual-Doppler (SDD) analysis. As such, a more detailed analysis of these storms is given, including examinations of low-level circulations, updraft strength and location, as well as a complete thermodynamic retrieval that evaluates the relative magnitudes of buoyancy and perturbation pressure. Of particular significance is the observation of the maximum updraft at a low height level for both storms.

Murphy, Todd Austin

195

Storm track response to climate change: Insights from simulations using an idealized dry GCM.  

NASA Astrophysics Data System (ADS)

The midlatitude storm tracks, where the most intense extratropical cyclones are found, are an important fixture in the general circulation. They are instrumental in balancing the Earth's heat, momentum, and moisture budgets and are responsible for the weather and climatic patterns over large regions of the Earth's surface. As a result, the midlatitude storm tracks are the subject of a considerable amount of scientific research to understand their response to global warming. This has produced the robust result showing that the storm tracks migrate poleward with global warming. However, the dynamical mechanisms responsible for this migration remain unclear. Our work seeks to broaden understanding of the dynamical mechanisms responsible for storm track migration. Competing mechanisms present in the comprehensive climate models often used to study storm track dynamics make it difficult to determine the primary mechanisms responsible for storm track migration. We are thus prompted to study storm track dynamics from a simplified and idealized framework, which enables the decoupling of mean temperature effects from the effects of static stability and of tropical from extratropical effects. Using a statistically zonally symmetric, dry general circulation model (GCM), we conduct a series of numerical simulations to help understand the storm track response to global mean temperatures and to the tropical convective static stability, which we can vary independently. We define storm tracks as regions of zonally and temporally averaged maxima of barotropic eddy kinetic energy (EKE). This storm track definition also allows us to use previously found scalings between the magnitude of bulk measures of mean available potential energy (MAPE) and EKE, to decompose MAPE, and to obtain some mechanistic understanding of the storm track response in our simulations. These simulations provide several insights, which enable us to extend upon existing theories on the mechanisms driving the poleward migration of the storm tracks. We demonstrate a poleward migration of the midlatitude storm tracks in dry atmospheres with fixed pole-equator temperature contrast and increasing radiative equilibrium mean temperature, without changes in convective static stability. We also show scalings between the location of maxima of surface MAPE and of barotropic EKE. In the simulations where we independently vary tropical convective static stability, we find a marked poleward migration of the storm tracks. However, our decomposition shows that meridional temperature gradients, and not static stability, determine the location and the intensity of the storm tracks. This suggests that although the storm tracks are sensitive to tropical convective static stability, it influences them indirectly. Furthermore, our simulations show that the storm tracks generally migrate in tandem with the terminus of the Hadley cell. Therefore, we hypothesize that it is possible that the Hadley cell provides the tropical-extratropical communication necessary to generate the storm track response to tropical convective static stability we observe in the simulations. The results contained herein could be used to supplement ongoing storm track research in moist atmospheres using comparatively more comprehensive GCMs to understand storm track dynamics in earth-like environments.

Mbengue, Cheikh; Schneider, Tapio

2013-04-01

196

Trajectory analysis of Saudi Arabian dust storms  

NASA Astrophysics Data System (ADS)

Temporal and spatial characteristics of Saudi Arabian dust storms, with focus on associated air parcel trajectories, are investigated using station and gridded weather observations and remotely-sensed aerosol optical depth (AOD). For 13 focal stations, an extensive pool of 84-h backward trajectories is developed for dust storm days, and the trajectories are grouped into 3-5 representative clusters based on the K-means technique and Silhouette Coefficients. Saudi Arabian dust storms are most prominent during February-June, with a mid-winter peak along the southern coast of the Red Sea, spring peak across northern Saudi Arabia around the An Nafud Desert, and early summer peak in eastern Saudi Arabia around the Ad Dahna Desert. Based on backward trajectories, the primary local dust source is the Rub Al Khali Desert and the primary remote sources are the Saharan Desert, for western Saudi Arabia, and Iraqi Deserts, for northern and eastern Saudi Arabia. During February-April, the Mediterranean storm track is active, with passing cyclones and associated cold fronts carrying Saharan dust to Saudi Arabian stations along the northern coast of the Red Sea. Across Saudi Arabia, the highest AOD is achieved during dust storms that originate from the Rub Al Khali and Iraqi Deserts. Most stations are dominated by local dust sources (primarily Rub Al Khali), are characterized by three dominant trajectory paths, and achieve AOD values exceeding 1. In contrast, for stations receiving predominantly remote dust (particularly Saharan), 3-5 trajectory paths emerge and AOD values only reach approximately 0.6 as dust is lost during transport.

Notaro, Michael; Alkolibi, Fahad; Fadda, Eyad; Bakhrjy, Fawzieh

2013-06-01

197

Global simulation of magnetosonic wave instability in the storm time magnetosphere  

Microsoft Academic Search

Coupling between the Rice Convection Model and Ring Current-Atmospheric Interactions Model codes is used to simulate the dynamical evolution of ring current ion phase space density and the thermal electron density distribution for the 22 April 2001 storm. The simulation demonstrates that proton ring distributions (df$\\\\perp$\\/dv$\\\\perp$ > 0) develop over a broad spatial region during the storm main phase, leading

Lunjin Chen; Richard M. Thorne; Vania K. Jordanova; Richard B. Horne

2010-01-01

198

Mapping of dust storms over the Indo-Gangetic Basin using multi sensor data  

NASA Astrophysics Data System (ADS)

Dust storms are common over the Indo-Gangetic basin during the summer season. In this basin million of population is located and hence, dust storms are major health threat. In countries like India, there are no such warnings that are made and as a result the day to day life is affected by these dust storms. In this paper, efforts have been made to utilize multi sensor data to study the characteristics of the dust storms. MODIS and MISR images clearly show the dust storm events in the Indo-Gangetic basin. The TOMS aerosol index and the AMSU data over the western end of the Gangetic basin have been analyzed. These data show the characteristic behavior due to dust which change significantly as the dust migrates towards the east over Kanpur. The TOMS aerosol index and the brightness temperature provide characteristic variations which confirm the presence of dust storm over the Indo-Gangetic basin.

El-Askary, H.; Gautam, R.; Singh, R.; Kafatos, M.

199

Storm time equatorial belt - an ``image'' of RC behavior  

NASA Astrophysics Data System (ADS)

During geomagnetic storms a well defined belt of trapped protons and ENAs (energetic neutral atoms) is observed around geomagnetic equator at low L-values. Their source is RC (ring current) protons existing at larger L-values. Through charge exchange with the geocorona RC protons become ENAs and if subjected to a new charge exchange become trapped protons. From low latitude particle observations at four different local times we follow; the RC injection region, the drift of RC-particles through the evening/afternoon into the morning sector, the RC-asymmetry and convection loss to the dayside during the storm initial and main phase, and its development into a symmetric RC in the recovery phase of the storm.

Søraas, F.; Oksavik, K.; Aarsnes, K.; Evans, D. S.; Greer, M. S.

2003-01-01

200

On magnetic storms and substorms  

NASA Astrophysics Data System (ADS)

Magnetospheric substorms and storms are indicators of geomagnetic activity. Whereas the geomagnetic index AE (auroral electrojet) is used to study substorms, it is common to characterize the magnetic storms by the Dst (disturbance storm time) index of geomagnetic activity. This talk discusses briefly the storm-substorms relationship, and highlights some of the characteristics of intense magnetic storms, including the events of 29-31 October and 20-21 November 2003. The adverse effects of these intense geomagnetic storms on telecommunication, navigation, and on spacecraft functioning will be discussed.

Lakhina, G. S.; Alex, S.; Mukherjee, S.; Vichare, G.

201

Investigating Convection  

NSDL National Science Digital Library

This experiment is designed to illustrate how fluids, including water, have the ability to flow. Learners use a tub, hot plate, ice and blue coloring to examine convection as well as circulation and energy transfer in oceans. Use this experiment as a group demonstration or assign it to small groups to complete individually. This activity is part of a larger lesson plan on "Exploring Polar Oceanography: Ocean Currents and Climate Connections."

Sillis, Alan

2011-01-01

202

Convection Demonstration  

NSDL National Science Digital Library

In this quick activity (located on page 2 of the PDF), learners will see the effects of convection and understand what makes hot air balloons rise. Learners will fill a bottle with hot water colored red and another bottle with cold water colored blue, then lower both into a container of water and observe the interaction of liquids of different temperatures/densities. Relates to the linked video, DragonflyTV GPS: Balloon Fiesta.

Twin Cities Public Television, Inc.

2007-01-01

203

Solar Radiation Storm  

NSDL National Science Digital Library

This past week has offered much excitement for space weather scientists and enthusiasts, alike. On Friday July 14, a major flare shot off the surface of the sun, pummeling Earth with a massive solar-radiation storm that interfered with satellite and radio communications and delayed a Russian space launch. The flare was one of the most powerful of the current eleven-year solar cycle (and the biggest solar radiation event since 1989) and was followed by a coronal mass ejection -- "a blast of billions of tons of electrically charged atomic particles and magnetic energy hurled in the Earth's direction at 3 million miles an hour" (1). When a very powerful coronal mass ejection hits the Earth's magnetosphere, a shock wave can compress the magnetosphere and unleash a geomagnetic storm -- causing interference with electric power transmission and triggering beautiful aurorae. Friday's flare was one of three storms last week, and the biggest since a small solar storm made the news in June (see the June 9, 2000 Scout Report for additional resources). Although this weekend's storms have diminished, more activity is anticipated as the sunspot group that is producing flares (region 9077) will continue to face the earth for another week.

Payne, Laura X.

204

Reverse convection  

SciTech Connect

A model of magnetospheric topology for periods when the interplanetary magnetic field (IMF) points northward indicates that reverse convection can readily occur when Earth's dipole or the IMF tilt toward or away from the Sun. In either case, all or part of one tail lobe drapes over the dayside, and the magnetopause merging voltage is applied directly to the ionosphere in that lobe only, to the center or nightside of the polar cap. The overdraped lobe forms layers both earthward and sunward of the magnetopause, similar to layers observed during periods of northward IMF. The model predicts two quasi-steady state patterns of reverse convection: (1) lobe cells in the polar cap of the overdraped lobe, generated by open-to-open flux transfer at the magnetopause and (2) merging cells in both polar caps, generated by closed-to-open flux transfer at the magnetopause and balanced open-to-closed transfer at an internal reconnection site, comparable to the tail merging site for southward IMF. The model also predicts transitional patterns of reverse convection for growing and shrinking polar caps in response to changes in dipole tilt and B[sub x] and in response to a sudden transition from southward to northward IMF. The model predicts theta aurora bar formation on the dawnside polar cap boundary when activation of the internal reconnection site ends polar cap growth. In this view the theta aurora becomes the northward IMF counterpart to substorms.

Crooker, N.U. (Univ. of California, Los Angeles (United States))

1992-12-01

205

Numerical Simulation of Andhra Severe Cyclone (2003): Model Sensitivity to the Boundary Layer and Convection Parameterization  

NASA Astrophysics Data System (ADS)

The Andhra severe cyclonic storm (2003) is simulated to study its evolution, structure, intensity and movement using the Penn State/NCAR non-hydrostatic mesoscale atmospheric model MM5. The model is used with three interactive nested domains at 81, 27 and 9 km resolutions covering the Bay of Bengal and adjoining Indian Peninsula. The performance of the Planetary Boundary Layer (PBL) and convective parameterization on the simulated features of the cyclone is studied by conducting sensitivity experiments. Results indicate that while the boundary layer processes play a significant role in determining both the intensity and movement, the convective processes especially control the movement of the model storm. The Mellor-Yamada scheme is found to yield the most intensive cyclone. While the combination of Mellor-Yamada (MY) PBL and Kain-Fritsch 2 (KF2) convection schemes gives the most intensive storm, the MRF PBL with KF2 convection scheme produces the best simulation in terms of intensity and track. Results of the simulation with the combination of MRF scheme for PBL and KF2 for convection show the evolution and major features of a mature tropical storm. The model has very nearly simulated the intensity of the storm though slightly overpredicted. Simulated core vertical temperature structure, winds at different heights, vertical winds in and around the core, vorticity and divergence fields at the lower and upper levels—all support the characteristics of a mature storm. The model storm has moved towards the west of the observed track during the development phase although the location of the storm in the initial and final phases agreed with the observations. The simulated rainfall distribution associated with the storm agreed reasonably with observations.

Srinivas, C. V.; Venkatesan, R.; Rao, D. V. Bhaskar; Hari Prasad, D.

2007-09-01

206

Determining the trigger of East Asian dust storms  

NASA Astrophysics Data System (ADS)

In the past 2 decades, there has been a dramatic increase in the occurrence of dust storms over East Asia. The trigger for this increase has been elusive because the ability of gusting wind to whip up a dust storm depends on a large number of factors, ranging from the level of snow and vegetation cover to differences in soil moisture and salt levels. Scientists note that these factors fall into two broad categories: Either the wind has increased its ability to wear away at the earth (increased erosivity), or the soil is more susceptible to the wind's assault (increased erodibility). Using a database of wind speed, weather, and dust storm observations stretching back to 1970, Kurosaki et al. sought to determine whether the East Asian increase was caused by changing erosivity or erodibility. The authors found that the rise in dust storms in desert regions could be attributed largely to an increase in the frequency of strong winds. For crops and grasslands, however, the researchers tied the increase in storms to a change in erodibility, indicating that the soil had somehow changed. They propose that changes in the ground cover provided by dead leaves in the spring could be the driving factor. If so, then observations of plant growth and precipitation during the summer could provide a platform on which to base forecasts of the frequency of dust storms the following year. (Geophysical Research Letters, doi:10.1029/2011GL047494, 2011)

Schultz, Colin

2011-08-01

207

Implications of Global SuperDARN Convection Measurements for the Selection Criteria of Steady Magnetospheric Convection Intervals  

NASA Astrophysics Data System (ADS)

Intervals of Steady Magnetospheric Convection (SMC) are loosely defined as times when convection is enhanced and no substorm signatures are observed. Several quantitative definitions have been developed to detect SMC events. These methods make use of AE indices, IMF conditions, in situ magnetotail observations, and the size of the auroral oval. None of these methods, however, relies on directly measured convection, and SMC events are, by definition, a convection phenomena. The SuperDARN radar network is an ideal tool with which to study SMC intervals because it gives a direct measurment of convection on a global scale. In this study we assess previous definitions of SMC using the SuperDARN global convection maps, and we present a modified method of SMC selection, using AE indices. O'Brien et. al. (GRL, 2002) presented a technique using the AE and AL indices to identify SMC intervals. Enhanced convection was quantified by a constant miminum AE cutoff value. Global SuperDARN convection maps for SMC events based on the O'Brien at al. technique revealed a seasonal dependence of the polar cap voltage for these SMC events, with lower voltages measured in the summer months. It is believed to be due to increased ionospheric conductivity in the summer, since AE is derived from ionospheric currents. Thus, equilavent AE values in winter and summer correspond to different levels of convection. Using a method that has a constant minimum AE cutoff therefore results in the selection of intervals that may not satisfy the qualitative criterion of enchanced convection, typical of SMC events. We found an optimal function to quantify enhanced convection, and this function varies throughout the year. By using this function, the seasonal dependance of conductivity on SMC interval selection is minimized. In doing so, the SMC event selection then becomes based primarily on convection.

Pfeifer, J.; McWilliams, K. A.; McPherron, R. L.

2006-12-01

208

Investigating the Importance of Viscous Interactions on Ionospheric Convection via Comparisons of Open-Closed Boundaries (OCBs) and Convection Reversal Boundaries (CRBs)  

NASA Astrophysics Data System (ADS)

Geomagnetic storms cause large global disturbances in the Earth's magnetosphere, during which large amounts of energy are deposited in the magnetotail and inner magnetosphere, producing an enhanced ring current and energising plasma to relativistic levels by poorly-understood excitation mechanisms. A previous study by Hutchinson et al. [2011] identified 143 geomagnetic storms over the last solar cycle (1997-2008) from the global SYM-H index and associated solar wind (SW) data from the Advanced Composition Explorer (ACE) spacecraft. Current work continues to use this dataset to investigate the characteristic ionospheric convection during magnetic storms via radar backscatter observed by the Super Dual Auroral Radar Network (SuperDARN). A superposed epoch analysis is completed using the map potential technique of Ruohoniemi and Baker [1998]. This technique has previously successfully been used to investigate substorm convection, however the technique has not particularly been employed for studies of geomagnetic storms nor has the model fit been applied to combined radar data from multiple storms for statistical studies rather than performing the analysis on an individual storm by storm basis. Latitude-Time-Velocity (LTV) plots, analogous to standard Range-Time-Intensity (RTI) plots, are used to visualise the results, which show the 'average' ionospheric response during different sized geomagnetic storms as the substorm control on the convection is mostly 'averaged out'. This, along with the cross-cap potential derived from the superposed SuperDARN results, is compared with similarly superposed auroral images from the IMAGE and POLAR spacecraft missions to better constrain the storm time coupling between the solar wind and magnetosphere. Results from the comparison of the convection reversal boundaries (derived from the SuperDARN data) and open-closed boundaries (from the auroral imagery) are presented to investigate the significance of a possible viscous interaction between the solar wind and the magnetosphere in addition to the normal reconnection-driven interaction.

Hutchinson, J. A.; Wright, D. M.; Milan, S. E.; Grocott, A.; Boakes, P. D.

2012-04-01

209

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

NASA Astrophysics Data System (ADS)

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

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

2010-10-01

210

Late-summer inflitration as affected by cropping and grazing management of winter-wheat pastures.  

Technology Transfer Automated Retrieval System (TEKTRAN)

Agricultural practices that incorporate grazed winter wheat and associated summer management are vital to the rural economy of the southern Great Plains. In regions where high intensity, late summer storms prevail, limited information exists about the impact of these practices, including chemical fa...

211

Interaction of Two Convective Scales Within a Severe Thunderstorm: A Case Study, and Thunderstorm Wake Vortex Structure and Aerodynamic Origin.  

National Technical Information Service (NTIS)

The study of a storm on 25 June 1969, reveals two interacting convective scales within a strongly sheared environment. The storm blends the multi-cell and super-cell types while propagating both discretely and continuously. Radar and surface data show sma...

L. R. Lemon

1974-01-01

212

Effects of cumulus convection on the simulated monsoon circulation in a general circulation model  

SciTech Connect

The effect of cumulus convection on the Asian summer monsoon circulation is investigated, using a general circulation model. Two simulations for the summer months (June, July, and August) are performed, one parameterizing convection using a mass flux scheme and the other without convective parameterization. The results show that convection has significant effects on the monsoon circulation and its associated precipitation. In the simulation with the mass flux convective parameterization, precipitation in the western Pacific is decreased, together with a decrease in surface evaporation and wind speed. In the indian monsoon region it is almost the opposite. Comparison with a simulation using moist convective adjustment to parameterize convection shows that the monsoon circulation and precipitation distribution in the no-convection simulation are very similar to those in the simulation with moist convective adjustment. The difference in the large-scale circulation with and without convective parameterization is interpreted in terms of convective stabilization of the atmosphere by convection, using dry and moist static energy budgets. It is shown that weakening of the low-level convergence in the western Pacific in the simulation with convection is closely associated with the stabilization of the atmosphere by convection, mostly through drying of the lower troposphere; changes in low-level convergence lead to changes in precipitation. The precipitation increase in the Indian monsoon can be explained similarly. 29 refs., 12 figs.

Zhang, Guang Jun (Univ. of California, San Diego, La Jolla, CA (United States))

1994-09-01

213

Slithering into Summer  

ERIC Educational Resources Information Center

|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

Scott, Catherine; Matthews, Catherine

2012-01-01

214

Transport of nitrogen and phosphorus from Rhode River watersheds during storm events  

NASA Astrophysics Data System (ADS)

We studied storm discharges of nitrate and dissolved and particulate forms of ammonium, organic N, phosphate, and organic P from four adjacent small watersheds of differing land use on the Atlantic Coastal Plain in Maryland. We used V-notch weirs and automated storm samplers to measure discharges and collect samples at flow intervals during 76 storms. The watershed aquifers are perched on an impervious clay layer slightly above sea level, so that combined groundwater and surface water discharges were measured at the weirs. The concentrations of particulate forms of organic N (PON), organic P (POP), and inorganic P (PPi) increased up to 3 orders of magnitude during storm events and usually peaked prior to the peak water discharge, while concentrations of dissolved forms of organic N (DON), organic P (DOP), inorganic P (DPi), and nitrate did not change very much. Dissolved and particulate ammonium (DNH4 and PNH4, respectively) concentrations increased up to fivefold in storm events but remained low compared to other N forms. The watershed with the most cropland discharged the highest concentrations of total N, PON, DNH4, nitrate, POP, and PPi. A forested watershed discharged the highest concentrations of DON, PNH4, and DOP. The watershed with the most grazed land discharged the highest concentration of DPi. PON and POP were the dominant forms of N and P in storm discharges from all watersheds. Concentrations of nitrogen were higher in spring and summer storms than in winter storms, but phosphorus concentrations were much higher in the summer storms than in spring or winter. The concentrations of PPi, POP, PON, DNH4, and PNH4 increased significantly with peak water discharge among storms, while concentrations of DPi, DOP, DON, and nitrate were not correlated with peak discharge. The ratios of TN/TP and TIN/TIP declined significantly with peak water discharge among storms.

Correll, David L.; Jordan, Thomas E.; Weller, Donald E.

1999-08-01

215

Desert Storm environmental effects  

Microsoft Academic Search

It is noted that after more than six months of operation of the Patriot launch station in the Saudi Arabian desert no problems that were attributed to high temperature occurred. The environmental anomalies that did occur were cosmetic in nature and related to dust and salt fog. It was concluded that the Desert Storm environmental effects were typical of worldwide

E. W. Kimball

1992-01-01

216

Desert Storm communications  

Microsoft Academic Search

An overview of the communication network that supported Operation Desert Storm is presented. The system, which maintained a 98% availability rate, supported 700000 telephone calls and 152000 messages per day. More than 30000 radio frequencies were managed to provide necessary connectivity and to ensure minimum interference. The roles of communications satellites, switched networks and terrestrial systems, and packet-switched networks and

J. S. Toma

1992-01-01

217

Operation Desert Storm  

Microsoft Academic Search

This paper presents a description of the objectives, planning, observations, and reports of a Department of Veteran's Affairs Social Work Outreach Team's efforts to work with soldiers returning from Operation Desert Storm. The soldiers reported experiences with discrimination, low morale, sexual harassment, and fear.

Lola West; Susan O. Mercer; Edith Altheimer

1993-01-01

218

Desert Storm environmental effects  

NASA Astrophysics Data System (ADS)

It is noted that after more than six months of operation of the Patriot launch station in the Saudi Arabian desert no problems that were attributed to high temperature occurred. The environmental anomalies that did occur were cosmetic in nature and related to dust and salt fog. It was concluded that the Desert Storm environmental effects were typical of worldwide hot, dry climates.

Kimball, E. W.

219

Mount Storm study  

Microsoft Academic Search

A 3-year study of coniferous foliage damaged by phytotoxic elements, compounds, and particulate matter in the Mt. Storm area of West Virginia and Maryland revealed that the major causal agents are waste products from coal-burning utility plants. The primary pollutant causing damage is sulfur dioxide and its by product sulfuric acid. The SOâ in the ambient air of the study

1972-01-01

220

California's Perfect Storm  

ERIC Educational Resources Information Center

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…

Bacon, David

2010-01-01

221

Stories from the Storm  

ERIC Educational Resources Information Center

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…

Smoczynski, Carol

2007-01-01

222

Geomagnetic Storm Theory  

Microsoft Academic Search

A discussion of the two-gas theory of the transmission of geomagnetic disturb- ances through the atmosphere (to several earth radii) is extended, with the following results: (i) The central problem concerning the main phase of a geomagnetic storm is the mechanism of penetration of solar ions into the geomagnetic field. An explanation is given depending on a combination of a

J. H. Piddington

1960-01-01

223

Great magnetic storms  

Microsoft Academic Search

The five largest magnetic storms that occurred between 1971 and 1986 are studied to determine their solar and interplanetary causes. All of the events are found to be associated with high speed solar wind streams led by collisionless shocks. The high speed streams are clearly related to identifiable solar flares. It is found that (1) it is the extreme values

Bruce T. Tsurutani; Yen Te Lee; Frances Tang; W. D. Gonzalez

1992-01-01

224

Weathering the storm  

SciTech Connect

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.

Burr, M.T.

1993-02-01

225

Convection and Precipitation: Moisture Convection and Meteorology.  

National Technical Information Service (NTIS)

The role of moisture convection in meteorology is considered. Because it involves small scale or mesoscale processes, moisture convection is not explicitly represented in numerical models. It nevertheless has a major impact on the dynamics of the atmosphe...

J. Testud

1991-01-01

226

Hurricane Sandy Storm Tide Mapper  

NSDL National Science Digital Library

United States Geological Survey (USGS) provides real-time map-based information from USGS storm tide sensors. The data is reflected on the Hurricane Sandy Tide Mapper. The mapper provides location information, site photos and data for storm tide and inland flooding. In addition, the data from these sensors is used to create models of the precise time the storm-tide arrived, how ocean and inland water levels changed during the storm, the depth of the storm-tide throughout the event, and how long it took for the water to recede.

227

Forecasting Dust Storms - Version 2  

NSDL National Science Digital Library

Forecasting Dust Storms Version 2 provides background and operational information about dust storms. The first part of the module describes dust source regions, the life cycle of a dust storm, and the major types of dust storms, particularly those found in the Middle East. The second part presents a process for forecasting dust storms and applies it to a case in the Middle East. Although the process refers to U.S. Department of Defense models and tools, it can easily be adapted to other forecast requirements and data sources. Note that this module is an updated version of the original one published in 2003.

Weingroff, Marianne

2007-02-02

228

Characterization of Rainfall Intensity and Storm Lifecycles in South Florida  

NASA Astrophysics Data System (ADS)

Understanding tropical thunderstorm cirrus anvil microphysics and their relation to the lifecycle and intensity of the thunderstorm's convective core will help improve modeling of these clouds and their environment. The Cirrus Regional Study of Tropical Anvils and Cirrus Layers - Florida Area Cirrus Experiment (CRYSTAL-FACE) was conducted over south Florida 2002. Measurements collected during the experiment provide an opportunity to study rainfall intensity and lifecycle characteristics of storms observed in South Florida. Data collected from the University of North Dakota's Citation research aircraft and the NASA S-Band polarimetric Doppler radar (NPOL) are used in this study. Storm events were selected from days throughout July that had coincident observations (space and time) between the Citation and NPOL. The intensity and general lifecycles of the thunderstorms and their convective cores are examined to find the maximum reflectivity, anvil height, 10 dBZ height, and 40 dBZ height. These values are then compared with the microphysical properties derived from Citation data, which includes the mean, mean volume, and median volume diameters, as well as the particle concentration. In a previous study of an event that occurred on 16 July, a positive correlation was found between the mean volume diameter, the maximum reflectivity, and maximum 40 dBZ height, as well as a slight negative correlation between the particle concentration and maximum anvil height. This study will expand on those results by examining several more cases during July. Through these comparisons, we are trying to determine if there are any relationships between the pre-storm environment, storm intensity, and properties of the cirrus anvil cloud of tropical convective systems.

Theisen, C. J.; Kucera, P. A.; Poellot, M. R.

2005-05-01

229

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

PubMed

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

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

230

Storm water pollution prevention plans  

SciTech Connect

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.

Rossmiller, R.L. (HDR Engineering, Inc., Bellevue, WA (United States))

1993-03-01

231

Characterizaton of convective systems in terms of cloud to ground lightning, cloud kinematics, vertical structure and precipitation  

Microsoft Academic Search

In vast regions of the world, especially over global oceans and sparsely populated land areas, satellite remote sensing is often the only practical mean of observing and tracking storm systems. This study investigates convective system characteristics from an array of remote sensing observations in two distinct convective regions on Earth (USA and Africa). It employs 112-hourly satellite Infrared observations along

Alemu Tadesse

2007-01-01

232

The News, Summer 1999-Summer 2000.  

ERIC Educational Resources Information Center

|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,…

Robertson, Trische, Ed.

2000-01-01

233

Urban effects on storm rainfall in Midwestern United States  

Microsoft Academic Search

A comprehensive 5-year field and analysis programme concerned with urban-induced effects on precipitation was recently completed at St Louis, Missouri, USA. Data obtained from operation of a network of 225 recording raingauges on 5200 km2 indicated an increase of approximately 30 per cent in summer rainfall in an area which is most frequently exposed to storms crossing the urban-industrial region.

Floyd A. Huff

234

Convective heater  

DOEpatents

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.

Thorogood, R.M.

1983-12-27

235

Winter Storm Lesson Plan  

NSDL National Science Digital Library

The subject of this lesson is Winter Storms. The length will be approximately 55 minutes (~15 minutes for each of the three websites and ~10 minutes for the students to create their slideshows). The slideshows may be presented the following day if not enough time is available. This lesson is intended for 4th grade and is directed towards Standard 2 of the 4th grade science core curriculum. This project explores factors that help create severe winter weather. An interactive simulation provides hands-on experience, followed by guiding questions and resource exploration. Winter Storms Connection to Standards: Utah Core Curriculum: Science Standard 2 (Students will understand that the elements of weather can be observed, measured, and recorded to make predictions and determine simple weather patterns.) NETS-T: 1. Facilitate and Inspire Student Learning and Creativity - Students will be using websites and situations that ...

S., Tasia

2010-09-23

236

Summer of Innovation  

NASA Website

[Educators Grades 4-9] [Available: Nationally] NASA's Summer of Innovation, or SoI, leverages current NASA research and discovery as a powerful context for student learning. The Summer of Innovation inspires middle school students and sparks ...

237

2011 Summer Student Research.  

National Technical Information Service (NTIS)

Multiple student research abstracts are included for summer 2011. All students presented their research results as posters or orals in the Undergraduate Research Summer Institute at Benedict College. Arianna Gladney won the second prize in oral competitio...

A. Gladney A. Lucas B. Fleming C. Qin J. Deputy

2012-01-01

238

LP Summer Student Program  

Cancer.gov

D  CCR Home   About CCR   CCR Intranet        Laboratory of Pathology LP Home Clinical Services Basic Sciences Training LP Staff Accessibility of Web Site LP Summer Student Program 2003/2004 Poster Day Images Past Student Images Summer Student Home About

239

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 runs from July 26 at 1315 UTC (9:15 a.m. EDT) to July 28 at 1045 UTC (6:45 a.m. EDT). (No audio) Credit: NASA/NOAA GOES Project

Robert Garner

2011-07-28

240

Investigating Magnetic Storms  

NSDL National Science Digital Library

In this activity, students use an internet archive of data on the Earth's magnetic field to study the frequency of magnetic storms of different intensities during the year, and during the solar sunspot cycle. The archive contains values of the Kp scale, an index of how disturbed the Earth's magnetic field was, on average, over each three-hour period of the day. They will select their data, construct a bar graph with it, and answer questions on what their data reveals.

Odenwald, Sten

241

Ice Storm Supercomputer  

ScienceCinema

"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.

242

Powerful Midwest Storm System  

NASA Video Gallery

This animation of imagery from NOAA’s GOES-13 satellite shows the movement of storm systems in the south central United States on May 20, 2013. Warm, moist gulf air flowing across Texas, Oklahoma, Kansas and Missouri triggered tornadoes, with an F-4 tornado (winds between 166 and 200 mph) crossing Moore, Okla., on May 20 around 3 p.m. CDT. Credit: NASA/NOAA GOES Project, Dennis Chesters › Related story › Download video

Robert Garner

2013-05-21

243

TWINS Observations of the 22 July 2009 Storm  

NASA Astrophysics Data System (ADS)

TWINS is the first mission designed to perform stereo imaging of the Earth’s ring current. The magnetic storm on 22 July 2009 is the greatest storm observed since the summer of 2008 when TWINS began its full science mode. 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 and our understanding on magnetospheric dynamics.

Fok, M. H.; Buzulukova, N.; Valek, P. W.; Goldstein, J.; McComas, D. J.

2009-12-01

244

Perturbation growth at the convective scale  

NASA Astrophysics Data System (ADS)

The development of ensemble forecasting techniques specific to the convective scale is now an active area of research. The aims of this study are to identify the physical processes that lead to perturbation growth at the convective scale in response to model state perturbations and determine the sensitivity to the characterisation of the perturbations. The Met Office Unified Model is run for case which is strongly upper-level forced but for which the detailed mesoscale/convective-scale evolution is dependent on smaller-scale processes. This case was observed during Intensive Observing Period 18 (IOP18) of the Convective Storms Initiation Project (CSIP). Potential temperature is perturbed at a specific model level within the boundary layer. The effects on perturbation growth of both the amplitude and typical scale-length of the perturbations are investigated and perturbations are applied either sequentially (every 30 min. throughout the model simulation) or at specific times. The direct effects (within one timestep) of the perturbations are to generate propagating Lamb and acoustic waves and produce generally small changes in cloud parameters and convective instability. In exceptional cases a perturbation at a specific gridpoint leads to switching of the diagnosed boundary-layer type or discontinuous changes in convective instability, through the generation or removal of a convective lid. The indirect effects (during the entire evolution) of the simulations are changes in the intensity and location of precipitation and the cloud-size distribution. Qualitatively different behaviour is found for strong (1K amplitude) and weak (0.01K amplitude) perturbations with sensitivity to the time of day found only for the weaker perturbations. However, the overall perturbation growth (as measured by the root mean square error of the accumulated precipitation) reaches similar values at saturation, regardless of the perturbation characterisation.

Leoncini, G.; Plant, R. S.; Gray, S. L.; Clark, P. A.

2009-04-01

245

Chasing Storms: Storm Photo Gallery and Case Study Page  

NSDL National Science Digital Library

John Monteverdi created this website to educate and entertain visitors in the science of storm chasing. Online storm journals for Spring Storm Chases from 1994 to the present take visitors through the life of a storm chaser. Throughout his discussions, the author provides weather charts and satellite images to assist visitors with the weather-related concepts. The site contains countless pictures of tornadoes and the destruction they leave behind. Although some of the amazing images take a few minutes to download, visitors will find that it is worth the wait.

Monteverdi, John P.

246

Slowing the Summer Slide  

ERIC Educational Resources Information Center

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…

Smith, Lorna

2012-01-01

247

Modeling Saturn's Giant Storms: Water, Ammonia, and the 30-Year Periodicity  

NASA Astrophysics Data System (ADS)

A giant planet-encircling storm occured on Saturn at the end of year 2010. The storm produced lightning at a rate greater than 10 SEDs per second. It wrapped around the planet, with a wake depleted in ammonia, and after 6 months it died. These kinds of storms are rare and episodic. They happen every 20-30 years. In this study, we discuss the role of moist convection on the development of the storm and explain the observed post-storm ammonia depletion. The study is composed of two parts. First, thermodynamcis on Saturn indicates that strong convection is prohibited by the waterloading-effect when the troposphere is warm. After 20-30 years, the troposphere has cooled below a critical value so that deep convection develops at the base of the water cloud. The deep water mixing ratio is best estimated as 1.2% relative to H2 so as to match the cooling time. Second, strong convection can produce a warm convective column that overshoots into the stratosphere. We solve the cylindrically symmetric hydrostatic primitive equations to investigate the large scale response of the ambient flow to the geostrophically unbalanced column. We find that during the subsequent large scale adjustment, ammonia vapor condenses and precipitates out of the troposphere, causing high residual brightness temperatures as observed by Cassini/RADAR (Janssen et al., 2013; Laraia et al., 2013). Further, for a deep water mixing ratio of 1.2%, we find that the ammonia vapor is depeleted down to 5 bar, that the speed of remaining anticyclonic vortex is about 30 m/s, and the residual large scale warming is about 10 K. These values are consistent with observation within the measurement uncertainties.

Li, Cheng; Ingersoll, A. P.

2013-10-01

248

Mechanisms of nutrient export in storm water runoff from catchments  

NASA Astrophysics Data System (ADS)

Regulatory policies aimed at preventing degradation of water resources benefit from understanding the processes that create water pollution. Understanding these processes requires determining what controls material export from the catchments that drain into the water bodies of interest. Export may vary through time, may vary among different land covers, and may derive from several vectors. Here, we focus on nutrients exported in storm water runoff from catchments in urban ecosystems. In the desert metropolis of Phoenix, Arizona, USA, we investigated whether features of storms and catchment land cover influenced the chemistry of runoff. We observed substantial variation in the load of nutrients exported in storm water. In runoff from single events, total nitrogen (TN) load ranged from 18 - 1147 g / ha, and total phosphorus (TP) load ranged from 3 - 266 g / ha. We hypothesized that this variation derived from variation in (i) storm activity, (ii) meteorological conditions preceding the storm, and (iii) catchment land cover. We found support for all hypotheses, though much variation remained unexplained. (i) Loads of TN and TP were positively correlated with precipitation intensity and with total precipitation. (ii) Loads were also positively correlated with the number of rainless days preceding the storm. Loads did not differ, however, between the types of climatic systems (summer monsoon vs. winter cold front) generating the storms. (iii) Loads positively correlated with housing density at both the metropolitan and continental scales. Variation in runoff chemistry was much greater among storms, however, than it was among different types of catchments. The biological consequences of nutrient flux from catchments to aquatic systems may be governed as much by nutrient ratios as by total nutrient loads. Thus, we also investigated mechanisms that produced variation in nutrient ratios in storm-water runoff. Molar N:P ratios ranged from 4 - 279, and were positively correlated with housing density. None of the other hypotheses explained variation in N:P ratios. Collectively, these results suggest that features of storms and urban design can exert a strong influence on the material exported from catchments to water bodies. The large amount of unexplained variance in export, however, warrants understanding the mechanisms by which nutrients are deposited onto to catchments in the first place.

Lewis, D. B.; Grimm, N. B.

2003-04-01

249

Response of ionosphere to strong geomagnetic storm: observation and modelling  

NASA Astrophysics Data System (ADS)

This paper presents the results derived from investigating the ionospheric response in middle and auroral latitudes to a strong geomagnetic storm on September 25, 1998. Our analysis of the behavior of the ionosphere was based on using the measurements from a network of ionospheric stations located in the region of Siberia and the Far East. According to the latitudinal location, the stations under consideration can be divided into three groups: auroral, subauroral, and mid-latitude stations. Data from some of European stations were used in the comparison. The numerical model for ionosphere-plasmasphere coupling that was developed at the ISTP SB RAS, was used to interpret the observational data. By analyzing the data, it was possible to identify the following regularities and differences. Intense negative disturbances during the main phase of the September 25 geomagnetic storm were observed at all stations under investigation. The main differences were marked both during the initial phase and in the recovery phase of the geomagnetic storm. The ionospheric response during the initial phase is determined primarily by the local time of geomagnetic storm onset and the latitude of station. The longitude effect of ionospheric disturbances was observed during the recovery phase. A theoretical analysis of the processes controlling the mid-latitude ionospheric response to the geomagnetic storm showed a good agreement of modeling results and measurements, as well as made it possible to ascertain the crucial role of the neutral composition variations in the ionospheric parameter variations observed. At auroral and subauroral stations the electron density variability during the storm is much more pronounced. According to results of analysis of the ionospheric plasma convection trajectories, this variability is caused by the combined effect of convection and energetic electron precipitation. Neutral thermospheric composition disturbances exert some influence on the electron density background level in this range of latitudes. The reversal of sign of the disturbance, when moving eastward from the west, during the storm recovery phase is difficult to explain by the local time effect. One possible reason could be the wave phenomena in the thermosphere, and local changes in the neutral wind system.

Pirog, P.; Polekh, P.; Tashchilin, T.; Romanova, R.; Zherebtsov, Z.

250

The life cycle of Redoubt's volcanic lightning storms  

NASA Astrophysics Data System (ADS)

The volcanic eruption of Alaska's Redoubt Volcano began on 23 March, 2009. Over a period of two weeks, 16 distinct explosions produced intense and prolific volcanic lightning storms. A 4-station Lightning Mapping Array (LMA) was used to record the electrical activity from the entire eruption and plan-position locations of the lightning discharges were obtained from the data. Detailed analysis of the data is providing insight into the nature and evolution of the charge structure of these volcanic lightning storms. The data suggest that two separate electrification processes occurred during the course of a single storm, which produced two phases of electrical activity. In the first process, highly charged volcanic material is jettisoned from the vent of the volcano, which gives rise to explosive phase discharges. During this phase we observed a steady haze of seemingly random amorphous electrical discharges over the volcano. These unique discharges occurred within an 1 km radius of the vent while the explosion was ongoing, and stopped abruptly when the explosion terminated. Following the explosion, gravitational sedimentation processes similar to those in meteorological thunderstorms dominate, where oppositely charged particles separate due to differing fall speeds. This gives rise to plume phase electrical discharges, occurring over and progressively downwind of the volcano. We have observed that the horizontal extent of the plume phase discharges was relatively small compared to the overall size of the storm when flash rates peaked early in the storm. Thereafter, the horizontal extent increased as flash rates declined over the lifetime of the storm. This progression to increasingly horizontally extensive discharges suggests that the charge layers also became horizontally extensive and that the ash plume became convectively quiescent.

Behnke, S. A.; Thomas, R. J.; Krehbiel, P. R.; Rison, W.; Edens, H. E.; McNutt, S. R.

2010-12-01

251

Forecasting Dust Storms - Version 2  

NSDL National Science Digital Library

This resource provides background and operational information about dust storms. The first part of the module describes dust source regions, the life cycle of a dust storm, and the major types of dust storms, particularly those found in the Middle East. The second part presents a process for forecasting dust storms and applies it to a case in the Middle East. Although the process refers to U.S. Department of Defense models and tools, it can easily be adapted to other forecast requirements and data sources. Note that this module is an updated version of the original one published in 2003 and is available in Spanish. Registration is required.

2010-12-22

252

a Diagnostic Study of Two Summer Depressions Over the Changjiang-Huaihe Valley  

NASA Astrophysics Data System (ADS)

Available from UMI in association with The British Library. Two summer depressions over the Changjiang-Huaihe Valley are investigated using data obtained from a synoptic observation network over East Asia and objectively analysed by applying a new scheme, which is mainly based on spline function interpolation. Detailed spatial structures and temporal evolution are documented in terms of pressure, temperature, moisture and wind fields. Vertical velocity fields are estimated using two independent methods, namely, the kinematic method and the quasi-geostrophic omega equation with consideration of stable and convective condensational heating. Quasi -Lagrangian budgets are computed for vorticity, kinetic energy, available potential energy, moisture and heat. The dynamic structures of the two depressions are analysed in terms of potential vorticity, moisture-related stabilities and geostrophic frontogenesis. Although their vertical structures and budget relations have some features typical of tropical disturbances, both depressions are closely related to a feeble Mei-yu front in the lower troposphere during their mature stage. Two different structures associated with the lower level frontal zone and a mid-upper layer warm belt are identified and related to the large scale circulation over East Asia. The adiabatic forcing under the quasi-geostrophic approximation is able to determine the general regions of ascent and descent associated with these depressions. On the other hand, the diabatic heating is the primary factor to account for the large magnitude of ascent, especially during the pre-storm and mature stages. Conditional symmetric instability and frontogenesis in the presence of small conditional symmetric stability are possible mechanisms in favour of the maintenance and development of the degressions. Based on these results, a conceptual model of the summer depressions over the Changjiang-Huaihe Valley is proposed.

Dingchen, Hou

1987-09-01

253

Saturn's Enigmatic "String of Pearls" and Northern Storm of 2010-2011: Manifestations of a Common Dynamical Mechanism?  

NASA Astrophysics Data System (ADS)

The "String of Pearls" (SoP) and the Northern Storm on Saturn near 34o north latitude may both be manifestations of convective processes at depth. As one possibility, the SoP may be a set of von Kármán vortex street features with convectively-driven updrafts as the driving obstacles. VIMS observations show marked increases in the size and latitudinal separation of the pearls (vortices) during the year prior to storm eruption, indicative of a growing convective system that may have subsequently erupted as a major thunderstorm. Other common convective mechanisms (uplift-driven Rossby waves, vortex-shedding from rising updrafts) may be possible. New VIMS images and spectra of the thunderstorm and SoP are presented.

Baines, K.; Momary, T.; Fletcher, L.; Showman, A.; Brown, R.; Buratti, B.; Clark, R.; Nicholson, P.; Go, C.; Wesley, A.

2011-10-01

254

Characteristics of one sprite-producing summer thunderstorm  

NASA Astrophysics Data System (ADS)

Twenty-nine sprites were observed during four years from 2007 to 2010 with one most sprite-productive storm on 1–2 August 2007 which produced 16 sprites. In this paper, the most sprite-productive storm is analyzed by using data from lightning detection network, Doppler radar, MTSAT (Multi-Function Transport Satellite) satellite, TRMM (Tropical Rainfall Measuring Mission), NCEP. The results show that most sprites appeared in groups and in shape of carrot. Most sprites occurred frequently when the cloud top brightness temperature is getting warm and radar reflectivity is becoming weak with characteristics of sharp decrease of negative CGs and slight increase of positive CGs. The parent cloud-to-ground lightning flashes (CGs) were positive and located in region with cloud top brightness temperature of ? 40 to ? 60 °C and radar reflectivity of 15–35 dBZ. The sprite-producing storm was fortunately scanned by TRMM during sprite time period. One orbit data could be used for PR (Precipitation Radar, 2A25) and two orbit data for TMI (TRMM Microwave Imager, 2A12 and 1B11). Results based on TRMM indicated that storm reflectivity with 30 dBZ was at about 12 km in the convective region and 4 km in stratiform region. The precipitation ice mostly located in 6–8 km with the largest value of 2.1 g/m3, but most cloud ice located between 10 and 14 km with no cloud ice below 6 km and very few at 6.0–8.0 km. The cloud water content located mostly between 4 and 6 km. Characteristics of vertical cross sections of radar reflectivity, precipitation ice and cloud ice agree well. Vertical cross sections along convective and stratiform regions show that contents of precipitation ice and cloud ice in convective region were larger than that in stratiform region. But cloud water in stratiform region was larger than that in convective region. The storm evolution could be seen clearly from characteristics of precipitation ice, cloud ice, cloud water and polarization corrected temperature at two different times. The CG distribution agrees well with low values of polarization corrected temperature region, indicating that lightning flashes have close relationship with ice particles. Although this paper is a case study of sprite-producing thunderstorm based on TRMM data, the results provided detailed information of microphysical structure of this sprite-producing storm.

Yang, Jing; Qie, Xiushu; Feng, Guili

2013-06-01

255

Projected future changes in tropical summer climate  

NASA Astrophysics Data System (ADS)

We analyze changes in the tropical sea surface temperature (SST), surface wind and other fields from the 20th to the 21st century in climate projections using the CMIP3 multimodel ensemble, focusing on the seasons January-March (JFM) and July-September (JAS). When the annual mean change is subtracted, the remaining “seasonal changes” have robust, coherent structures. The JFM and JAS changes resemble each other very closely after either a change of sign or reflection about the equator. The seasonal changes include an increase in the summer hemisphere SST and a decrease in the winter hemisphere SST. These appear to be thermodynamic consequences of easterly trade winds’ strengthening in the winter subtropics and weakening in the summer subtropics. These in turn are associated with the weakening and expansion of the Hadley circulation documented by previous studies, which themselves are likely consequences of changes in extratropical eddies. The seasonal SST changes influence the environment for deep convection: peak precipitation in the summer hemisphere increases by around 10% and convective available potential energy (CAPE) by as much as 25%. Comparable fractions of these changes are attributable to the annual mean change and the seasonal changes, though the two have very different spatial structures. Since the annual mean change is marked by relative warming in the northern hemisphere compared to the southern, the seasonal changes oppose the annual mean change in JFM and enhance it in JAS.

Sobel, A. H.; Camargo, S. J.

2010-12-01

256

Nonlinear convective motion in shallow convective envelopes  

Microsoft Academic Search

Finite-difference techniques are used to obtain numerical solutions to the conservation equations in two spatial dimensions and time for large-amplitude convective motion in two shallow convective envelopes slightly interior to the photosphere of a model main-sequence star. The calculations are carried to the point where shear motions break up the largest convection cells. The essentially linear problem of the formation

R. G. Deupree

1976-01-01

257

Current understanding of magnetic storms: Storm-substorm relationships  

Microsoft Academic Search

This paper attempts to summarize the current understanding of the storm\\/substorm relationship by clearing up a considerable amount of controversy and by addressing the question of how solar wind energy is deposited into and is dissipated in the constituent elements that are critical to magnetospheric and ionospheric processes during magnetic storms. (1) Four mechanisms are identified and discussed as the

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

1998-01-01

258

Spatial Variability of Summer Florida Precipitation and Its Impact on Microwave Radiometer Rainfall-Measurement Systems  

Microsoft Academic Search

Three-dimensional radar data for three summer Florida storm are used as input to a microwave radiative transfer model. The model simulates microwave brightness observations by a 19-GHz, nadir-pointing, satellite-borne microwave radiometer.The statistical distribution of rainfall rates for the storms studied, and therefore the optimal conversion between microwave brightness temperatures and rainfall rates, was found to be highly sensitive to the

B. J. Turner; G. L. Austin

1993-01-01

259

EarthStorm  

NSDL National Science Digital Library

EarthStorm is part of the educational outreach of the Oklahoma Climatological Survey (OCS). It provides workshops, lesson plans, classroom activities and potential speakers as resources for K-12 educators. It highlights student projects that use data provided by OCS. Scientific staff are available as mentors. Career information about the atmospheric sciences is also provided. Weather data in terms of weather facts, climate maps, daily weather maps and Oklahoma mesonet information is accessible. Earthstorm also hosts various online forums. Many of the activities focus on the use of Oklahoma mesonet data but are adaptable to other data sources.

2007-03-09

260

EarthStorm  

NSDL National Science Digital Library

EarthStorm is part of the educational outreach of the Oklahoma Climatological Survey (OCS). It provides workshops, lesson plans, classroom activities and potential speakers as resources for K-12 educators. It highlights student projects that use data provided by OCS. Scientific staff are available as mentors. Career information about the atmospheric sciences is also provided. Weather data in terms of weather facts, climate maps, daily weather maps and Oklahoma mesonet information is accessible. Earthstorm also hosts various online forums. Many of the activities focus on the use of Oklahoma mesonet data but are adaptable to other data sources.

261

GOES sounding improvement and applications to severe storm nowcasting  

NASA Astrophysics Data System (ADS)

An improved clear-sky physical retrieval algorithm for atmospheric temperature and moisture is applied to the Geostationary Operational Environmental Satellite-12 (GOES-12) Sounder. A comparison with the microwave radiometer (MWR) measured total precipitable water (TPW) at the Southern Great Plains (SGP) Cloud and Radiation Testbed (CART) site from June 2003 to May 2005 shows that the TPW retrievals are improved by 0.4 mm over the legacy GOES Sounder TPW product. The Lifted Index (LI) derived product imagery (DPI) from the improved soundings better depicts the pre-convective environment surrounding a tornadic supercell at Eagle Pass, Texas on 24 April 2007. Another severe storm case from 13 April 2006 demonstrates that the improved physical algorithm successfully detects low-level moisture. Both cases show the new retrievals along with the derived products will help the forecasters with short-term severe storm nowcasting.

Li, Zhenglong; Li, Jun; Menzel, W. Paul; Schmit, Timothy J.; Nelson, James P.; Daniels, Jaime; Ackerman, Steven A.

2008-02-01

262

Outreach Plans for Storm Peak Laboratory  

NASA Astrophysics Data System (ADS)

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.

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

2006-12-01

263

Added value of convection permitting seasonal simulations  

NASA Astrophysics Data System (ADS)

In this study the added value of a ensemble of convection permitting climate simulations (CPCSs) compared to coarser gridded simulations is investigated. The ensemble consists of three non hydrostatic regional climate models providing five simulations with ~10 and ~3 km (CPCS) horizontal grid spacing each. The simulated temperature, precipitation, relative humidity, and global radiation fields are evaluated within two seasons (JJA 2007 and DJF 2007-2008) in the eastern part of the European Alps. Spatial variability, diurnal cycles, temporal correlations, and distributions with focus on extreme events are analyzed and specific methods (FSS and SAL) are used for in-depth analysis of precipitation fields. The most important added value of CPCSs are found in the diurnal cycle improved timing of summer convective precipitation, the intensity of most extreme precipitation, and the size and shape of precipitation objects. These improvements are not caused by the higher resolved orography but by the explicit treatment of deep convection and the more realistic model dynamics. In contrary improvements in summer temperature fields can be fully attributed to the higher resolved orography. Generally, added value of CPCSs is predominantly found in summer, in complex terrain, on small spatial and temporal scales, and for high precipitation intensities.

Prein, A. F.; Gobiet, A.; Suklitsch, M.; Truhetz, H.; Awan, N. K.; Keuler, K.; Georgievski, G.

2013-04-01

264

How Will Changes in Moisture with Global Warming Impact Midlatitude Storms: A Study Using Idealized Moist Baroclinic Life Cycles  

NASA Astrophysics Data System (ADS)

Global Climate Models predict that atmospheric moisture content will increase with global warming. This study examines how these changes may affect midlatitude storms, using a baroclinic wave experiment in the NCAR Weather Research Forecasting model. Two experiments were conducted, one in which the moisture in the initial conditions is altered, and a second in which the saturation vapor pressure was multiplied by a constant. The following storm characteristics were examined: eddy kinetic energy (EKE), sea level pressure minimum, and extreme surface winds and precipitation. We found that the storm strength, based on all of the above metrics, increased monotonically with moisture content, for moisture levels going from dry to the level closest to observations. When the moisture was increased beyond current observed levels, the storm response changed, becoming sensitive to the behavior of the cumulus convection scheme. Our analysis found that large increases in moisture create strong conditional instabilities in the lower latitudes of the storm domain, and the upright convection disturbs the alignment of the surface and upper level storm circulations. This results in a weaker EKE. However, the storm precipitation and surface wind speed maxima both increase.

Booth, J. F.; Wang, S.; Polvani, L. M.

2011-12-01

265

Effects of different geomagnetic storm drivers on the ring current: CRCM results  

NASA Astrophysics Data System (ADS)

The storm-time magnetic disturbance at the Earth's equator, as commonly measured by the Dst index, is induced by currents in the near-Earth magnetosphere. The ring current is generally considered the most important contributor, but other magnetospheric currents have also been found to have significant effects. Of the two main types of solar geomagnetic storm drivers, Coronal Mass Ejections (CMEs) tend to have a much greater impact on Dst than Corotating Interaction Regions (CIRs). Ring current models have been found to underestimate Dst, particularly during storms driven by CIRs. One possible explanation is that the models neglect to handle some aspect of ring current physics that is particularly important for CIRs. This study uses the Comprehensive Ring Current Model (CRCM) to estimate the ring current contribution to Dst for a selection of storms of various strengths and different drivers (CMEs and CIRs) that have solar wind parameters that fit a typical profile. The model boundary is set to 10 RE at the equator, encompassing the entire ring current region. The magnetic field is held fixed, based on average storm parameters, which limits our model results to the effects of convection and plasma sheet density at the model boundary. Our model results generally show good agreement with the size and timing of fluctuations in Dst, which indicates that convection and boundary conditions play an important role in shaping Dst. We also find excellent agreement with the magnitude of Dst for CME-driven storms. For CIR-driven storms, however, the magnitude at the peak of the storm frequently deviates from actual Dst. In general, we agree with the results of previous research that CIR-driven storms are more underpredicted. However, this study includes some weaker CIR-driven storms for which Dst is actually overpredicted. Overall, when examining the dependence of modeled Dst* on actual Dst* at storm peak, we find that there is a statistically significant difference between CME- and CIR-driven storms. We also find that approximately half of the total ring current energy lies beyond an L-value of 6.6. However, this figure could be overestimated due to the use of a static magnetic field, which limits radial transport.

Cramer, W. D.; Turner, N. E.; Fok, M.-C.; Buzulukova, N. Y.

2013-03-01

266

Microsubstances in urban storm water  

Microsoft Academic Search

During 1976 a catchment in Gôteborg was investigated with respect to microsubstances in storm water and atmospheric fallout. The microsubstances studied were 17 heavy metals and PCB, DDT with derivatives, HCB and PAH. The concentrations of heavy metals in storm water were not remarkably high compared with the concentrations in waste water and sometimes in drinking water. For As, Cd,

Birgitta Horkeby; Per-Arne Malmquist

1976-01-01

267

Substorms during different storm phases  

NASA Astrophysics Data System (ADS)

After the deep solar minimum at the end of the solar cycle 23, a small magnetic storm occurred on 20-26 January 2010. The Dst (disturbance storm time) index reached the minimum of -38 nT on 20 January and the prolonged recovery that followed the main phase that lasted for about 6 days. In this study, we concentrate on three substorms that took place (1) just prior to the storm, (2) during the main phase of the storm, and (3) at the end of the recovery of the storm. We analyse the solar wind conditions from the solar wind monitoring spacecraft, the duration and intensity of the substorm events as well as the behaviour of the electrojet currents from the ground magnetometer measurements. We compare the precipitation characteristics of the three substorms. The results show that the F-region electron density enhancements and dominant green and red auroral emission of the substorm activity during the storm recovery resembles average isolated substorm precipitation. However, the energy dissipated, even at the very end of a prolonged storm recovery, is very large compared to the typical energy content of isolated substorms. In the case studied here, the dissipation of the excess energy is observed over a 3-h long period of several consecutive substorm intensifications. Our findings suggest that the substorm energy dissipation varies between the storm phases.

Partamies, N.; Juusola, L.; Tanskanen, E.; Kauristie, K.; Weygand, J. M.; Ogawa, Y.

2011-11-01

268

Hydromagnetic Theory of Geomagnetic Storms  

Microsoft Academic Search

A hydromagnetic theory is presented which explains the average characteristics of geomagnetic storms. The magnetic storm is caused by a sudden increase in the intensity of the solar wind. Stresses are then set up in the geomagnetic field by the solar plasma impinging upon the geomagnetic field and becoming trapped in it. These stresses, which are propagated to the earth

A. J. Dessler; E. N. Parker

1959-01-01

269

SOLIDS IN STORM WATER RUNOFF  

Microsoft Academic Search

This paper discusses the way in which storm water solids, particularly total suspended solids (TSS) are defined, sampled and measured. High concentration of pollutants associated with the finer fraction of solids in storm water has seen these particles receive the bulk of management attention. However, it is proposed here that traditional sampling methods commonly used significantly underestimate the mass of

Roger B. James

270

Wireless Telegraphy and Magnetic Storms  

Microsoft Academic Search

A recent theory of auroras and magnetic storms attributes these phenomena to the action of a flash of ultraviolet light from the sun. The flash causes an unusual ionization in the Kennelly-Heaviside layer. Therefore, it is only daylight wireless circuits which are, or may be, disturbed at the commencement of the magnetic storm, the night circuits remaining normal until dawn

H. B. Maris; E. O. Hulbiurt

1929-01-01

271

Ice storms and forest impacts  

Microsoft Academic Search

Ice storms, or icing events, are important meteorological disturbances affecting forests over a surprisingly large portion of the USA. A broad belt extending from east Texas to New England experiences major ice storms at least once a decade; and truly major events occur in the heart of this belt once or twice a century. In the areas most affected, icing

Lloyd C Irland

2000-01-01

272

Storm-time E-region radar backscatter observed by the SuperDARN HF radars  

NASA Astrophysics Data System (ADS)

Storm-time coherent echoes observed by the SuperDARN HF radars in the short ranges corresponding to the E-region backscatter are investigated. Analysis of the spatial distribution of the echoes shows that during storms most of the echoes are detected at locations that are close to the expected locations calculated using a straight-line propagation model (i.e. assuming no radar wave refraction). Analysis of the E layer critical frequency, foE, from one subauroral ionosonde station confirmed that during storms foE typically decreases to lower values as compared with normal conditions. This result suggests that the electron density in the E region is often depleted during storms. The progression of depletion with storm-time and MLT is analysed using several SuperDARN radars separated in longitude. The types of short-range echoes detected during storms are also examined. A new storm-time population of echoes is identified; the echoes exhibit small negative Doppler velocities for a large range of spectral widths. Local ionospheric plasma convection velocity measurements are then used to study the conditions favorable for the generation of these echoes.

Carter, B. A.; Makarevich, R. A.

2008-12-01

273

Comparison of Rainfall Characteristics and Convective Properties of Monsoon Precipitation Systems over South China and Yangtze-and-Huai River Basin  

NASA Astrophysics Data System (ADS)

Rainfall characteristics and convective properties of monsoon precipitation systems over the South China (SC) and the Yangtze-and-Huai River Basin (YHRB) are investigated by combining a gridded daily precipitation data product based on surface station observations, a Tropical Rainfall Measuring Mission dataset, the CloudSat and Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations data products. Atmospheric aerosol amounts are inferred using a Moderate Resolution Imaging Spectroradiometer aerosol product. Comparison between the two regions is made for their monsoon active periods to reveal variations of the monsoon precipitation systems along with the northward march of the East Asian summer monsoon rainbelt from the SC to the YHRB. Relative to the YHRB, precipitation systems over the SC occur more frequently, resulting in larger maxima of the monsoon rainfall accumulation, but the SC systems are convectively less intense which is linked to the contrasts in strength of low-level vortices and surface fronts between the two regions. Contrasting among the pre-monsoon, monsoon active and break, and post-monsoon periods is also conducted for each region to unveil intraseasonal transitions of the precipitation systems, atmospheric conditions, and weather systems. Convective activities of the precipitation systems enhance progressively from the pre-monsoon to the monsoon and further to the post-monsoon period at both regions with more significant convection intensification from the pre-monsoon to the monsoon period at the YHRB, being largely in agreement with the intraseasonal variations of atmospheric thermodynamic conditions (convective available potential energy). From the pre-monsoon to the monsoon periods, the lightning flash rates decrease substantially at the SC, in contrast to the YHRB where the rates increase slightly. While aerosol loading is in favor of electrification during the pre-monsoon periods at both regions, the convective strength of the YHRB pre-monsoon is too weak to boost up lightning activity. The SC region, on the other hand, has more similar convective intensity from the pre-monsoon to the active monsoon, so aerosol effect stands out. Moreover, horizontal extents of precipitation systems are larger (smaller) on average during the monsoon active and pre-monsoon (post-monsoon and break) periods, which can be largely explained by the scale difference of the driving mechanisms: the precipitation storms are less controlled by large-scale weather systems (dynamically driven) but more by local instability due to solar heating (thermodynamically driven) during the post-monsoon and break periods.

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

2012-04-01

274

Colorful Convection Currents  

NSDL National Science Digital Library

In this activity, students create artifical convection currents using hot and cold water, food coloring, and bottles. A materials list, instructions, and a brief explanation of the convection phenomenon are included.

275

Mantle Convection Modeling  

NSDL National Science Digital Library

This research page provides links to two animations of modeled mantle convection, showing the progression of convection over millions of years. There are also links to other work and publications by the author.

Livnat, Yarden; Utah, University O.

276

Ice storms and forest impacts.  

PubMed

Ice storms, or icing events, are important meteorological disturbances affecting forests over a surprisingly large portion of the USA. A broad belt extending from east Texas to New England experiences major ice storms at least once a decade; and truly major events occur in the heart of this belt once or twice a century. In the areas most affected, icing events are a factor that shapes stand composition, structure, and condition over wide areas. Impacts of individual storms are highly patchy and variable, and depend on the nature of the storm. Impacts also depend on how (or if) forest managers conduct subsequent salvage cuttings. Important research needs remain to be considered by the forest ecology and meteorology communities. At present, how ice storm frequency and severity may change with future climate change is unknown. PMID:11087029

Irland, L C

2000-11-15

277

Dynamics of Saturn's great storm of 2010–2011 from Cassini ISS and RPWS  

NASA Astrophysics Data System (ADS)

Saturn's quasi-periodic planet-encircling storms are the largest convecting cumulus outbursts in the Solar System. The last eruption was in 1990 (Sánchez-Lavega, A. [1994]. Chaos 4, 341-353). A new eruption started in December 2010 and presented the first-ever opportunity to observe such episodic storms from a spacecraft in orbit around Saturn (Fischer, G. et al. [2011]. Nature 475, 75-77; Sánchez-Lavega, A. et al. [2011]. Nature 475, 71-74; Fletcher, L.N. et al. [2011]. Science 332, 1413). Here, we analyze images acquired with the Cassini Imaging Science Subsystem (ISS), which captured the storm's birth, evolution, and demise. In studying the end of the convective activity, we also analyze the Saturn Electrostatic Discharge (SED) signals detected by the Radio and Plasma Wave Science (RPWS) instrument. The storm's initial position coincided with that of a previously known feature called the String of Pearls (SoPs) at 33°N planetocentric latitude. Intense cumulus convection at the westernmost point of the storm formed a particularly bright "head" that drifted at -26.9 ± 0.8 m s-1 (negative denotes westward motion). On January 11, 2011, the size of the head was 9200 km and up to 34,000 km in the north-south and east-west dimensions, respectively. RPWS measurements show that the longitudinal extent of the lightning source expanded with the storm's growth. The storm spawned the largest tropospheric vortex ever seen on Saturn. On January 11, 2011, the anticyclone was sized 11,000 km by 12,000 km in the north-south and east-west directions, respectively. Between January and September 2011, the vortex drifted at an average speed of -8.4 m s-1. We detect anticyclonic circulation in the new vortex. The vortex's size gradually decreased after its formation, and its central latitude shifted to the north. The storm's head moved westward and encountered the new anticyclone from the east in June 2011. After the head-vortex collision, the RPWS instrument detected that the SED activities became intermittent and declined over ˜40 days until the signals became undetectable in early August. In late August, the SED radio signals resurged for 9 days. The storm left a vast dark area between 32°N and 38°N latitudes, surrounded by a highly disturbed region that resembles the mid-latitudes of Jupiter. Using ISS images, we also made cloud-tracking wind measurements that reveal differences in the cloud-level zonal wind profiles before and after the storm.

Sayanagi, Kunio M.; Dyudina, Ulyana A.; Ewald, Shawn P.; Fischer, Georg; Ingersoll, Andrew P.; Kurth, William S.; Muro, Gabriel D.; Porco, Carolyn C.; West, Robert A.

2013-03-01

278

Celebrate Summer with Reading  

NSDL National Science Digital Library

School is out and the summer 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 summer. So along with your beach chairs, flags, and fireworks schedules; collect some reading material for a summer of personal enrichment.

Texley, Juliana

2007-07-01

279

Detection of Infrasonic Energy From Tornado-Producing Storms  

NASA Astrophysics Data System (ADS)

There are numerous reports in the literature on the observation of infrasound emitted from tornadic thunderstorms. Most of these observations have been made from sensors that are several hundreds of kilometers from the location of the storm, and "ground truth" about the tornadic activity is not well established. We report here on a campaign carried out during the summer of 2011 in which 50 infrasound microphones (whose approximate frequency response is 0.01-500 Hz) developed at the University of Mississippi were deployed by members of Hyperion Technology Group and their associates as part of an ongoing multi-university program on hazard detection and alert funded by the National Oceanic and Atmospheric Administration (NOAA). In this campaign, our deployment teams were able to deploy sensors along the paths of developing tornadic storms, including sensors that were located between twin F5 tornados near Oklahoma City on May 24, 2011. For this particular deployment we had sensors located a few kilometers from the northern most F5 tornado, and a second array, composed of three linear element arrays, that was optimally northeast of the storm. (A total of 7 tornados touched down in this area during this particular severe weather outbreak.) Substantial meteorological information, including ground truth about tornados (intensity and size as a function of time), and the relative close proximity of the sensors to the storms, provides us with a level of detail not available in previous storms. We will report on our infrasound measurements and analysis (source strength, frequency content as a function of tornadic intensity) from this outbreak as well as data from two other interceptions of tornadic storms, which occurred on the dates of May 30 and June 19, 2001.

Talmadge, C. L.; Waxler, R.; Kleinert, D. E.; Carter, G. E.; Godbold, G.; Harris, D. R.; Williams, C.

2011-12-01

280

FASEB Summer Research Conferences  

NSDL National Science Digital Library

This website provides information regarding summer research conferences hosted internationally by FASEB. The conferences spread a wide range of scientific specialties and serve academics and health professionals.

2012-07-24

281

Monsoon convection in the Himalayan region as seen by the TRMM Precipitation Radar  

Microsoft Academic Search

Three-dimensional structure of summer monsoon convection in the Himalayan region and its overall variability are examined by analyzing data from the Tropical Rainfall Measuring Mission (TRMM) Precipitation Radar over the June-September seasons of 2002 and 2003. Statistics are compiled for both convective and stratiform components of the observed radar echoes. Deep intense convective echoes (40 dBZ echo reaching heights >10

Robert A. Houze Jr; Darren C. Wilton; Bradley F. Smull

2007-01-01

282

Multiple modes of storm runoff generation in a North Carolina coastal plain watershed  

Microsoft Academic Search

The results of field measurements conducted in a small (19.37 ha) agricultural watershed on the North Carolina coastal plain during the summer of 1996 are presented. The objective of the study was to develop a more complete understanding of basin response in the region with respect to stormflow generation and, in particular, to identify the processes that determine storm runoff

Michael C. Slattery; Paul A. Gares; Jonathan D. Phillips

2006-01-01

283

A Look at Dust Storms on Mars (2007 To 2009) Using MCS and THEMIS Observations  

Microsoft Academic Search

Martian dust storms may be small, localised and short lived or can be large and intense and expand to enshroud most, if not all, of the planet within a few days. The martian dusty season occurs near the time of perihelion (closest approach to the sun) during Mars' southern hemisphere spring and summer. During this period (+\\/- 90 degrees Ls

William Flynn; N. E. Bowles; N. A. Teanby; L. Montabone; S. B. Calcutt; P. L. Read; D. M. Kass; A. S. Hale

2009-01-01

284

Enhanced level of water vapor during dust storms over the Indo-Gangetic basin  

Microsoft Academic Search

The Asian desert regions including Sahara desert (Africa) are well known as one of the major sources of natural mineral dust aerosols in the atmosphere. Recent studies using ground data and satellites show that all major dust storms affecting the aerosol loading in the Indo-Gangetic (IG) basin during the pre-monsoon (summer) season invariably originate from these regions. But unlike dry

R. P. Singh; A. K. Prasad

2006-01-01

285

Overstory and understory leaf area index as indicators of forest response to ice storm damage  

Microsoft Academic Search

Leaf area index (LAI) was measured with the tracing radiation and architecture of canopies (TRAC) optical instrument in three consecutive summers from 1999 to 2001 in sugar maple forests across eastern Ontario to monitor recovery from ice storm damage suffered in January 1998. The study sites were experimental blocks of the Ontario Ministry of Natural Resources (OMNR) designed for measurement

Ian Olthof; Douglas J. King; R. A. Lautenschlager

2002-01-01

286

Overstory and understory leaf area index as indicators of forest response to ice storm damage  

Microsoft Academic Search

Leaf area index (LAI) was measured with the tracing radiation and architecture of canopies (TRAC) optical instrument in three consecutive summers from 1999 to 2001 in sugar maple forests across eastern Ontario to monitor recovery from ice storm damage suffered in January 1998. The study sites were experimental blocks of the Ontario Ministry of Natural Resources (OMNR) designed for measurement

Ian Olthof; Douglas J. King; R. A. Lautenschlager

2003-01-01

287

Changes in submerged plants at the South end of Cayuga Lake following Tropical Storm Agnes  

Microsoft Academic Search

Tropical Storm Agnes produced increased suspended sediments and decreased water transparency at the southern end of Cayuga Lake for a sustained period during the early summer of 1972. The 1972 community of submerged vascular plants was severely affected. Standing crops were drastically reduced and the species composition of the plant community changed compared to 1970. In 1973, standing crop values

Ray T. Oglesby; Albert Vogel; John H. Peverly; Robert Johnson

1976-01-01

288

How Strong ENSO Events Affect Tropical Storm Activity over the Western North Pacific  

Microsoft Academic Search

An analysis of 35-yr (1965-99) data reveals vital impacts of strong (but not moderate) El Niño and La Niña events on tropical storm (TS) activity over the western North Pacific (WNP). Although the total number of TSs formed in the entire WNP does not vary significantly from year to year, during El Niño summer and fall, the frequency of TS

Bin Wang; Johnny C. L. Chan

2002-01-01

289

Prediction and Identification of Flash Flood Storms in Colorado. Part I: Attributes of Environment and Storm Evolution  

NASA Astrophysics Data System (ADS)

Heavy rainfall and hail frequently occur in association with intense, summertime convective storms that form along the foothills and eastern plains of the Colorado Rocky Mountains. Heavy rainfall amounts over localized regions can result in flash flooding in mountain communities and in the dense urban areas along the Front Range, disrupting traffic, causing damage to property and in extreme events, resulting in loss of life. Various approaches have been taken over the years to provide the best possible estimations of quantitative precipitation (QPE) and nowcasts and short-term forecasts of heavy precipitation (QPN and QPF, respectively) in order to assess the potential for flash floods over the 0-6 hr time period and to accurately model and predict streamflow increases and runoff. Ten Colorado flash flood and hailstorm events that occurred during the period from 2008-2012 are examined in detail in Parts I and II of this study to benchmark our current understanding of the attributes and evolution of flash flood events and determine how to improve our prediction and identification of those storms that are likely to produce heavy rainfall of short duration over very specific regions and basins sensitive to flooding. In Part I of this study, we utilize instrumentation available from the Front Range Observational Network Testbed (FRONT) located along the Colorado Front Range. This testbed includes 5 dual-polarimetric Doppler S-band radars and a variety of operational and experimental surface, upper air, and satellite observing systems. These detailed observations provide high resolution observations of wind, temperature, moisture, stability, precipitation rate and accumulation. The events are characterized by environments with relatively high moisture content for the area, both in the boundary layer and at mid-levels and conditionally unstable atmospheres either over the plains or over the mountains, or both. Boundary layer and steering level winds were generally between 2.5 - 15 m/s (5-30 kts), so storms were either semi-stationary or not moving particularly fast. Numerous storms formed on these days, but the heaviest rainfall and flash flood resulted from merging storms, back-building storms, and the continual re-initiation of new storms over the same elevated terrain locations during the afternoon period. The collision of convergence boundaries over the plains and the enhancement of existing storms by convergence boundary passage resulted in the formation of large, semi-stationary storms that proceeded to rain heavily over the Denver urban area, and caused one fatality on one of the days. On another day, the storms that formed all seemed rather similar in character, but the rainfall associated with storms that passed over a recent fire burn area caused flooding in that sensitive land area. Identifying and improving the prediction of those specific storms that will produce the heaviest rainfall or case substantial flooding is challenging. Use of basic extrapolation techniques are not sufficient for prediction of heavy rainfall and flooding events (see Part II). Planned efforts include using the documented attributes of the ten heavy precipitation events to develop improved, location-specific, detection and prediction of heavy precipitation storms.

Roberts, Rita; Wilson, James

2013-04-01

290

GPS tomography for analysing storm density anomalies in mid-latitude ionosphere  

NASA Astrophysics Data System (ADS)

During magnetic storms dramatic changes in the solar wind pressure combined with appropriate orientation of the interplanetary magnetic field lead to the intensification of magnetosphereionosphere coupling which causes sudden inputs of the solar wind energy into the ionosphere. This results in extreme disturbances of the height and density of ionospheric layers during the main phase of magnetic storms. The tomographic inversion of the GPS data acquired by ground-based network of GPS receivers has been applied to reconstruct the 4D dynamics of ionospheric plasma during some major magnetic storms of the recent solar maximum. Dramatic storm-time enhancements of ionospheric plasma density and vertical plasma content (TEC) appear in mid-latitude ionosphere in dayside and evening sectors extending to high latitudes in the form of "ionization tongue". A number of physical mechanisms could be responsible for the formation of the storm-time density anomalies including the expansion of high-latitude plasma convection, neutral wind effects and the intensification of equatorial electrojet. Analysis of plasma flows deduced from GPS tomography and in-situ measurements by LEO spacecraft suggests that the major portions of mid-latitude density anomalies are linked to the dramatic expansion of high-latitude plasma convection though some features of the mid-latitude anomalies indicate an involvement of other physical mechanisms.

Pokhotelov, Dimitry; Mitchell, Cathryn; Spencer, Paul; Smith, Nathan; Budd, Chris

291

The Tropical Transition of Western Pacific Tropical Storm 16W  

NASA Astrophysics Data System (ADS)

The breaking of synoptic scale Rossby waves is a common occurrence along the extratropical waveguide. During such events, stratospheric intrusions into the troposphere of high potential vorticity (PV) air retain only a thin connection to the stratospheric body of air. In some cases, these so-called PV streamers can extend a significant distance equatorward, concomitantly serving as an atmospheric destabilization mechanism. As such, they have been observed to play a role in heavy precipitation events and subtropical cyclogenesis. Intriguing evidence that PV streamers might also serve as extratropical precursors to tropical cyclogenesis events exists in the form of composite and case-study analyses of a limited number of Atlantic events. For this to occur, the system must transition from a cold to a warm core system. This process has been termed tropical transition (TT). The Tropical Cyclone Structure (TCS) 2008 field program provided a unique opportunity to study the TT process in the western Pacific basin. TCS037 was a storm system identified in realtime during the field program as a possible candidate for a TT-like event: deep convection was associated with an upper-level disturbance emanating from the extratropics. This study examines the evolution of TCS037 from this early stage of deep convection in an environment with significant vertical wind shear (a condition detrimental to tropical cyclone formation) to a weak tropical storm. Specifically, we invoke PV and Lagrangian frameworks to examine the processes via which (i) a distinct PV streamer served as a forcing mechanism for deep convection, and (ii) near-continuous convection aided in the erosion of the deleterious vertical wind shear, ultimately resulting in a conducive local environment for tropical cyclogenesis to ensue.

Schoenenberger, F.; Moore, R.; Martius, O.

2010-09-01

292

Analyses of Storm Events in an Adirondack Watershed: a Combined Approach Using Stable Isotopes of Sulfate and Nitrate, Chemistry and Hydrology  

NASA Astrophysics Data System (ADS)

The Archer Creek catchment which is the major inlet to Arbutus Lake at the Huntington Forest in the Adirondack Mountains of New York has been the focus of intensive investigations on hydrological and biogeochemical interactions. We used hydrologic information, solute chemistry and isotopic composition of nitrate (? 15N and ? 18O) and sulfate (? 34S and ? 18O) to evaluate how four summer/early autumn storms affected surface water chemistry after a summer of unusually dry conditions in 2002. Precipitation amounts varied among the storms (Storm 1--Sept. 14-18, 19 mm; Storm 2--Sept. 21-24, 33 mm; Storm 3--Sept. 27-29, 43 mm; Storm 4--Oct. 16-21, 68 mm). With the four storms there was an increase in water yield from 2 to 14%. The first storms resulted in relatively small changes in water chemistry. With progressive storms the changes in water chemistry became more marked with particularly major changes in Cb (sum of base cations), sulfate, nitrate, DOC and pH. The marked changes in chemistry were also reflected in changes in the isotopic composition of sulfate and nitrate. The results indicate that especially for storms 3 and 4 that there was an important solute source most likely attributable to wetlands. The contributions of wetlands was evident due to the large increases in DOC during the storm and evidence of changes in S wetland constituents from both chemical and isotopic information. Although these late summer and fall storms do not play a major role in the overall annual mass balances of solutes for this watershed, these events have distinctive chemistry including depressed pH that have important consequences to watershed processes and the linkage of these processes to climate change.

Mitchell, M. J.; Piatek, K.; Mayer, B.; Kendall, C.; Page, B.; Christopher, S.

2004-05-01

293

Winter Storm Activity  

NSDL National Science Digital Library

This project explores factors that help create severe winter weather. An interactive simulation provides hands-on experience, followed by guiding questions and resource exploration. Weather affects our everyday lives. Some days it's sunny and some days its not. The years weather is split up into seasons. 1. What are the four seasons? 2. What kind of weather do you see in the summer? 3. What kind of weather is unique to winter? 4. What ...

Haight, Jennifer

2010-02-22

294

A numerical study of three-dimensional gravity waves triggered by deep tropical convection and their role in the quasi-biennial oscillation  

Microsoft Academic Search

A three dimensional mesoscale model is used to examine the structure of gravity waves triggered by tropical convection and their role in the dynamics of the lower tropical stratosphere. Three distinct cases of tropical convection are considered. The first case is thought to be representative of a seasonal thunderstorm storm, named Hector, occurring over North West Australia during the northern

Claudio Piani

2000-01-01

295

Hurricane: Storm Science  

NSDL National Science Digital Library

The Miami Museum of Science educational Web site provides a fun and interactive page called Hurricane: Storm Science. The main page consists of a clickable illustration that includes a Inside a Hurricane link where kids can learn what hurricanes are, how they form, and how to understand a radar image; see a cutaway picture of a hurricane; and more. The weather instruments page lets students explore and complete activities on wind, moisture, temperature, air pressure, and weather measuring tools. Other interesting areas of the site include how radar tracks hurricanes, an interactive exercise to learn how this is done, and even stories that have been submitted by people who have survived hurricanes and other disasters.

2000-01-01

296

School Construction Summer Slam  

ERIC Educational Resources Information Center

|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 summer when students are on break and the campus is quieter. Although these "summer slammers" often are…

Jensen, Richard F.

2012-01-01

297

RELIABILITY OF DESIGN STORMS IN MODELLING  

Microsoft Academic Search

Stormwater runoff is generally simulated using a design storm as input. The use of design storms significantly reduces the complexity of stormwater runoff analysis. As a result, the use of design storms is popular among engineers. The basic premise behind their use is that a design storm of a given return frequency will produce a simulated runoff peak and volume

BEN U RBONAS; URBAN D RAINAGE

298

Steamship Portland: X-Storms  

NSDL National Science Digital Library

In this lesson students will discover what causes extreme storms such as the Portland Gale of 1898 and the Halloween Nor'easter of 1991. They will identify and explain three factors that contributed to extreme storm conditions in the northwest Atlantic Ocean, off New England, discover how to obtain real-time and historical meteorological data, and compare and contrast extra-tropical cyclones, tropical cyclones, and hybrid storms. This hands-on activity uses on-line data resources and includes: focus questions, learning objectives, teaching time, audio/visual materials needed, background information, learning procedures, evaluations, extensions, as well as resources and student handouts.

Goodwin, Mel

299

Magnetospheric Storms at Saturn and Earth  

NASA Astrophysics Data System (ADS)

Terrestrial magnetospheric storms are a well-known phenomenon in which plasma from the solar wind and the ionosphere is convected into the inner magnetosphere ("ring current") and energized by betatron acceleration and rapid changes in the magnetic field (substorms). Here we compare terrestrial storm characteristics with similar, newly found characteristics of Saturn's magnetosphere. We characterize Saturn's magnetospheric response to solar wind variability by using remote energetic neutral atom (ENA) measurements with simultaneous in-situ solar wind measurements when Cassini was outside the Saturnian magnetosphere. The Ion and Neutral Camera on board the Cassini spacecraft have obtained global energetic neutral atom (ENA) images of the hot plasma of Saturn's magnetosphere since July 2004. INCA obtains ENA images in the ~3-200 keV/nuc of protons and O+. The typical observations show hot plasma distributed roughly between 6 to 30 RS orbiting the planet at a period around the 10h45min rotation period depending on energy and species. However, some observations show how ENA intensity builds up on the nightside during intervals longer than the rotation period which indicates a gradual source of plasma. The intervals are often ended by a dramatic ENA intensification followed by a rotation of the newly injected plasma around the planet. We have selected a few of such intervals when Cassini was in the solar wind and could obtain solar wind parameters and simulataneous ENA image sequences. We use the Magnetic Field Experiment (MFE), the Cassini Charge Energy Mass Spectrometer (CHEMS), and the Cassini Plasma Spectrometer Subsystem (CAPS) to study the IMF, solar wind speed and density during these events and find that Saturn's magnetospheric activity most likely depends more on solar wind pressure than magnetic field orientation.

Brandt, P.; Mitchell, D.; Rymer, A.; Hill, M.

2007-08-01

300

Statistical comparison of interplanetary conditions causing intense geomagnetic storms (Dst ? -100 nT)  

NASA Astrophysics Data System (ADS)

It is well known that intense southward magnetic field and convection electric field (V × B) in the interplanetary medium are key parameters that control the magnitude of geomagnetic storms. By investigating the interplanetary conditions of 82 intense geomagnetic storms from 1998 to 2006, we have compared many different criteria of interplanetary conditions for the occurrence of the intense geomagnetic storms (Dst ? -100 nT). In order to examine if the magnetosphere always favors such interplanetary conditions for the occurrence of large geomagnetic storms, we applied these conditions to all the interplanetary data during the same period. For this study, we consider three types of interplanetary conditions as follows: Bz conditions, Ey conditions, and their combination. As a result, we present contingency tables between the number of events satisfying the condition and the number of observed geomagnetic storms. Then we obtain their statistical parameters for evaluation such as probability of detection yes, false alarm ratio, bias, and critical success index. From a comparison of these statistical parameters, we suggest that three conditions are promising candidates to trigger an intense storm: Bz ? -10 nT for >3 h, Ey ? 5 mV/m for >2 h, and Bz ? -15 nT or Ey ? 5 mV/m for >2 h. Also, we found that more than half of the “miss” events, when an intense storm occurs that was not expected, are associated with sheath field structures or corotating interacting regions. Our conditions can be used for not only the real-time forecast of geomagnetic storms but also the survey of interplanetary data to identify candidate events for producing intense geomagnetic storms.

Ji, Eun-Young; Moon, Y.-J.; Kim, K.-H.; Lee, D.-H.

2010-10-01

301

Cyber Storm II. Final Report.  

National Technical Information Service (NTIS)

The National Cyber Exercise: Cyber Storm II successfully executed on March 10 - 14, 2008 at player locations across the United States, as well as in international partner locations in Australia, Canada, New Zealand, and the United Kingdom. The Department ...

2009-01-01

302

27 Storms: Arlene to Zeta  

NSDL National Science Digital Library

This video from NASA presents the 2005 hurricane season with actual data that NASA and NOAA satellites measured. Sea surface temperatures, clouds, storm tracks, and hurricane category labels are shown as the hurricane season progresses.

Nasa

2010-04-12

303

Resolved and unresolved reasons for magnetic storms  

NASA Astrophysics Data System (ADS)

IMAGE/HENA has imaged more than a two dozens of geomagnetic storms of various strengths since its launch in March 2000. In all storms the peak of the ion differential flux during the mainphase has been concentrated to the midnight and even the post-midnight region. The classical picture of the E-field of the inner magnetosphere has been a sum of the solar wind convectional and corotational field, which produces a pattern with a potential minimum around dusk. Therefore the peak of the ion differential flux was expected to be located around dusk. In this presentation we have investigate 19 relatively long-lasting main phases for storms with a minimum Dst<=-50 nT. The local time location of the peak ion differential flux extends from 22 magnetic local time (MLT) to as far as 06 MLT. The local time angle is found to depend on the clock angle of the interplanetary magnetic field (IMF), with the most severe rotation towards dawn occuring when IMF Bz is strongly negative and IMF By is strongly positive. The morphology of the ion distribution is about the same in the entire 10-200 keV range, which suggests that this pattern can be explained in terms of a strong (1-10 mV/m) electric field at L<5, that focus the ions to the post midnight sector by ExB drift. Substorm injections during the main phase decay away during ~1 in the 27-60 keV range, which suggests that the ions exit the magnetopause around dusk or afternoon local time. Strong E-fields in the inner magnetosphere has been suggested by in-situ observations by CRESS and ground-based radar observations by the Millstone Hill facility (J. Foster, Haystack Observatory, MIT, MA). We present kinetic model runs by M. -C. Fok (this conference) and M. Liemohn and A. Ridley (this conferene) that self consistently calculates the E-field set up by the closure of the partial ring current in the low-latitude ionosphere, where the conductivity is low. The potential drop in the ionosphere therefore becomes high, which then feeds back out into the equatorial magnetosphere. We briefly discuss the effects of stagnation of the earthward when it reaches a region where the magnetic drift cancels the electric drift.

Brandt, P. C.; Fok, M.; Liemohn, M.; Ohtani, S.; Mitchell, D. G.; Ridley, A.; Roelof, E. C.; Demajistre, R.

2002-05-01

304

Easterly Wind Storms over Israel  

Microsoft Academic Search

Summary   Continental wind storms are common along the Mediterranean coast. Along the northern coast they are mostly cold, similar\\u000a to the Bora or the Mistral, and along the southern coast they are mostly warm, e.g., the Ghibli or the Shirocco. At the eastern\\u000a Mediterranean basin and the Levant region, these storms are intermittently warm and cold during the same season

H. Saaroni; B. Ziv; A. Bitan; P. Alpert

1998-01-01

305

Hurricane Katrina Storm Surge Reconnaissance  

Microsoft Academic Search

Hurricane Katrina August 23-30, 2005 was one of the costliest and deadliest hurricanes to ever strike the United States, impacting low-lying coastal plains particularly vulnerable to storm surge flooding. Maximum storm surges, overland flow depths, and inundation distances were measured along the Gulf Coast of Florida, Alabama, Mississippi, and Louisiana. The vehicle-based survey was complemented by inspections with the reconnaissance

Hermann M. Fritz; Chris Blount; Robert Sokoloski; Justin Singleton; Andrew Fuggle; Brian G. McAdoo; Andrew Moore; Chad Grass; Banks Tate

2008-01-01

306

Energy flux in the Earth's magnetosphere: Storm substorm relationship  

NASA Astrophysics Data System (ADS)

Three ways of the energy transfer in the Earth's magnetosphere are studied. The solar wind MHD generator is an unique energy source for all magnetospheric processes. Field-aligned currents directly transport the energy and momentum of the solar wind plasma to the Earth's ionosphere. The magnetospheric lobe and plasma sheet convection generated by the solar wind is another magnetospheric energy source. Plasma sheet particles and cold ionospheric polar wind ions are accelerated by convection electric field. After energetic particle precipitation into the upper atmosphere the solar wind energy is transferred into the ionosphere and atmosphere. This way of the energy transfer can include the tail lobe magnetic field energy storage connected with the increase of the tail current during the southward IMF. After that the magnetospheric substorm occurs. The model calculations of the magnetospheric energy give possibility to determine the ground state of the magnetosphere, and to calculate relative contributions of the tail current, ring current and field-aligned currents to the magnetospheric energy. The magnetospheric substorms and storms manifest that the permanent solar wind energy transfer ways are not enough for the covering of the solar wind energy input into the magnetosphere. Nonlinear explosive processes are necessary for the energy transmission into the ionosphere and atmosphere. For understanding a relation between substorm and storm it is necessary to take into account that they are the concurrent energy transferring ways.

Alexeev, Igor I.

2003-04-01

307

Severe Weather Research at the European Severe Storms Laboratory  

NASA Astrophysics Data System (ADS)

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.

Groenemeijer, Pieter

2013-04-01

308

Further case studies on the impact of mesoscale convective systems on regional ozone and haze distributions  

SciTech Connect

The report is a continuation of an earlier effort to study the impact of mesoscale convective precipitation systems upon distributions of aerosol and photochemical oxidant pollutants in the planetary boundary layer (PBL). Analyses of surface visibility and ozone data revealed a dramatic response in the boundary-layer pollutant patterns to the passage of two very large convective storm systems. Regional visibilities, at times less than 5 km, increased dramatically over a multistate area to as high as 80 km. The resultant clean air region was termed a convective aerosol removal event (CARE). In the study, a well-defined CARE was found off the Georgia coast on 14 August 1980.

Lyons, W.A.; Calby, R.H.

1986-04-01

309

Regional variation of morphology of organized convection in the tropics and subtropics  

NASA Astrophysics Data System (ADS)

Properties of organized convection with large horizontal area (> 1000 km2) and with different horizontal structures in the tropics and subtropics are investigated by using 14 years of Tropical Rainfall Measuring Mission observations. First, the convective features (CFs) are defined as contiguous areas of convective precipitation detected by the Tropical Rainfall Measuring Mission precipitation radar. Using the minor and major axes of fitted ellipses, the morphology of the CFs are described as closer to a circular or a line shape. Regional variations and the properties of organized convection are examined with CFs with area > 1000 km2 after categorizing them by their shapes. Organized convection tends to have larger extent and a higher fraction of near-circular shapes over land than over ocean. Shallow organized convection with maximum radar echo top height below 4.5 km is found mainly over ocean and some coastal regions. Of all tropical oceans, most shallow organized convection is found over the east Pacific. The fraction of line shaped organized convection is higher over the ocean than over land, and is higher in the subtropics than in the tropics. More convective lines are found in winter than in summer over oceans, but more in summer over land. Organized convective lines are slightly less convectively intense indicated by lower 30 dBZ echo top heights and warmer 37 GHz brightness temperatures than those with near-circular shapes. Orientations of organized convective lines are often aligned with fronts, dry lines, warm ocean currents, coastlines, and mountain slopes. Over the subtropics, organized convective lines are tilted more east-west over land, and more north-south over oceans. The largest and the most intense convective lines are found over central Africa, Argentina, and southeast U.S. over land, and over several warm currents in subtropical oceans.

Liu, Chuntao; Zipser, Edward

2013-01-01

310

STORM-E Geomagnetic Correction to Auroral Zone E-Region Peak Electron Density  

Microsoft Academic Search

An auroral zone empirical geomagnetic storm correction to ionospheric E-region peak electron density has been developed. The empirical storm model called STORM-E was produced from a database of storm-to-quiet correction factors derived from infrared radiance measurements taken by the Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) instrument on the Thermosphere-Ionosphere-Mesosphere Energetics and Dynamics (TIMED) satellite. The storm-time correction

Christopher Mertens; Xiaojing Xu; Jose Fernandez; Dieter Bilitza; J. M. Russell III; M. G. Mlynczak

2010-01-01

311

Eye of the Storm  

NSDL National Science Digital Library

This Website showcases materials from the recently published Simon & Schuster book, Eye of the Storm, which details in vivid watercolors, maps, and journal entries, events from the Civil War as witnessed by Union soldier Private Knox Sneden. The site offers 20 selections from Knox's diaries covering from 1861 to December of 1864, each accompanied by a watercolor or map viewable in two sizes, as well as four Flash presentations of these watercolors based around particular incidents Knox witnessed. The watercolors, while not masterpieces, are fine renderings of characteristic events of the war -- a surprise artillery attack by Rebels against an overconfident and underobservant Union fortification, a surrendering of 10,000 troops, views of battles, sabotage operations, and the like. More than anything, they give a sense of the harsh imprint of war upon an otherwise typically bucolic countryside. Knox's dark lines of soldiers, scarred earth, and flames reflected in slow running rivers show that America's bloodiest war touched not only its people, but its landscape as well.

312

NCI Summer Curriculum in  

Cancer.gov

This 4-week summer course provides specialized instruction in the principles and practice of cancer prevention and control. It focuses on concepts, methods, issues, and applications related to this field.

313

Focus on summer products  

Microsoft Academic Search

This summer season provides a selection of new products: a rabbit model for AIDS, a monoclonal antibody specific for the retinoblastoma gene product, and a reagent for keeping cell lines mycoplasma-free.

Diane Gershon

1989-01-01

314

Global simulation of magnetosonic wave instability in the storm time magnetosphere  

NASA Astrophysics Data System (ADS)

Coupling between the Rice Convection Model and Ring Current-Atmospheric Interactions Model codes is used to simulate the dynamical evolution of ring current ion phase space density and the thermal electron density distribution for the 22 April 2001 storm. The simulation demonstrates that proton ring distributions (df?/dv? > 0) develop over a broad spatial region during the storm main phase, leading to the instability of equatorial magnetosonic waves. Calculations of the convective growth rate of magnetosonic waves for multiples of the proton gyrofrequency from 2 to 42 are performed globally. We find that the ratio between the perpendicular ring velocity and the equatorial Alfven speed determines the frequency range of unstable magnetosonic waves. Low harmonic waves (? < 10 ? tend to be excited in the high-density nightside plasmasphere and within the duskside plume, whereas higher-frequency waves (? > 20 ? are excited over a broad spatial region of low density outside the morningside plasmasphere.

Chen, Lunjin; Thorne, Richard M.; Jordanova, Vania K.; Horne, Richard B.

2010-11-01

315

Under Summer Skies  

NSDL National Science Digital Library

Thereâs no better way to celebrate 2009, the International Year of Astronomy, than by curling up with a good book under summer skies. To every civilization, in every age, the skies inspired imagination and scientific inquiry. Thereâs no better place to start your summer reading than under their influence. Here are a few selections identified by NSTA Recommendsâ network of reviewers to help get you started.

Texley, Juliana

2009-07-01

316

Convection forced by a descending dry layer and low-level moist convergence  

NASA Astrophysics Data System (ADS)

A narrow line of convective showers was observed over southern England on 18 July 2005 during the Convective Storm Initiation Project (CSIP). The showers formed behind a cold front (CF), beneath two apparently descending dry layers (i.e. sloping so that they descended relative to the instruments observing them). The lowermost dry layer was associated with a tropopause fold from a depression, which formed 2 d earlier from a breaking Rossby wave, located northwest of the UK. The uppermost dry layer had fragmented from the original streamer due to rotation around the depression (This rotation was also responsible for the observations of apparent descent-ascent would otherwise be seen behind a CF). The lowermost dry layer descended over the UK and overran higher ?w air beneath it, resulting in potential instability. Combined with a surface convergence line (which triggered the convection but had less impact on the convective available potential energy than the potential instability), convection was forced up to 5.5 km where the uppermost dry layer capped it. The period when convection was possible was very short, thus explaining the narrowness of the shower band. Convective Storm Initiation Project observations and model data are presented to illustrate the unique processes in this case.

Russell, Andrew; Vaughan, Geraint; Norton, Emily G.; Ricketts, Hugo M. A.; Morcrette, Cyril J.; Hewison, Tim J.; Browning, Keith. A.; Blyth, Alan M.

2009-03-01

317

Storm time electric field penetration observed at mid-latitude  

SciTech Connect

During the height of the February 8-9, 1986, magnetic storm the Millstone Hill radar was in the evening local time sector (1600-2200 MLT). Radar observations indicate that high speed (>1,000 m s{sup {minus}1}) westward ion flow penetrated deeply below 50{degree} invariant latitude ({Lambda}) and persisted for 6 hours between 2100 UT on February 8 and 0300 UT on February 9. The double-peaked ion convection feature was pronounced throughout the period, and the separation in the dual maxima ranged from 4{degree} to 10{degree}. The latitude positions of the high-latitude ion drift peak and the convection reversal varied in unison. The low-latitude ion drift peak ({approximately}49{degree}{Lambda} or L =2.3) did not show significant universal time/magnetic local time (UT/MLT) variation in its latitude location but showed a decrease in magnitude during the initial recovery phase of the storm. Using simultaneous particle (30 eV-30 keV) precipitation data from the DMSP F6 and F7 satellites, the authors find the high-latitude ion drift peak to coincide with the boundary plasma sheet/central plasma sheet transition in the high ionospheric conductivity (>15 mho) region. The low-latitude ion drift peak lay between the equatorward edges of the electron and soft (< 1 keV) ion precipitation in the low conductivity region ({approximately}1 mho). A comparison between the low-altitude observations and simultaneous ring current observations from the high-altitude AMPTE satellite further suggests that the low-altitude ion drift peak is closely related to the maximum of the O{sup +} dominated ring current energy density in magnetic latitude. The low-latitude ion drift peak is the low-altitude signature of the electric field shielding effect associated with ring current penetration into the outer layer of the storm time plasmasphere.

Yeh, H.C.; Foster, J.C. (Massachusetts Insti. of Tech., Westford (USA)); Rich, F.J.; Swider, W. (Geophysics Lab., Hanscom AFB, MA (USA))

1991-04-01

318

Tornadoes and severe storms in Spain  

NASA Astrophysics Data System (ADS)

A climatology of tornadoes, waterspouts, and straight winds linked to convection 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 storms, 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.

Gayà, Miquel

2011-06-01

319

Ionospheric response to the sustained high geomagnetic activity during the March '89 great storm  

Microsoft Academic Search

A simulation was conducted to model the high-latitude ionospheric to the sustaied level of high geomagnetic activity for the great magnetic storm period of March 13-14, 1989. The geomagnetic and solar activity indices and the Defense Meterological Satellite Program (DMSP) F8 and F9 satellite data for particle precipitation and high-latitude convection were used as inputs to a time-dependent ionospheric model

J. J. Sojka; R. W. Schunk; W. F. Denig

1994-01-01

320

Ionospheric response to the sustained high geomagnetic activity during the March `89 great storm  

Microsoft Academic Search

A simulation was conducted to model the high-latitude ionospheric to the sustaied level of high geomagnetic activity for the great magnetic storm period of March 13-14, 1989. The geomagnetic and solar activity indices and the Defense Meterological Satellite Program (DMSP) F8 and F9 satellite data for particle precipitation and high-latitude convection were used as inputs to a time-dependent ionospheric model

J. J. Sojka; R. W. Schunk; W. F. Denig

1994-01-01

321

Relative Importance of Storm-Time Mechanisms in the Observed TEC Response to the March 31, 2001 Geomagnetic Storm  

NASA Astrophysics Data System (ADS)

The interpretation of the global state of TEC storm effects requires knowledge of electric fields, neutral winds, temperature and composition changes. Observational data, such as GPS TEC measurements, combined with a data assimilation model are ideal to reveal ionospheric structures. However, identifying, understanding and quantifying each mechanism's role in TEC variations during magnetically disturbed periods are quite difficult when only observational measurements are used. In order to understand all these physical processes, the global, three-dimensional, time-dependent, non-linear coupled model of the thermosphere, ionosphere, plasmasphere and electrodynamics (CTIPe) can be used to investigate and understand the dynamic and electrodynamic response of the global ionosphere during magnetic storms. CTIPe is a self-consistent model and solves the momentum, energy, and composition equations for the neutral and ionized atmosphere. It requires a few external drives, such as solar UV and EUV, Weimer electric field, TIROS/NOAA auroral precipitation, tidal forcing from the lower atmosphere, and penetration electric fields from the Rice Convection Model (RCM). Model results are compared to observational data to identify the relative importance of each mechanism in the ionosphere response to the March 31, 2001 geomagnetic storm.

Fedrizzi, M.; Fuller-Rowell, T. J.; Maruyama, N.; Codrescu, M.; Araujo-Pradere, E. A.; Anderson, D.; Anghel, A.

2005-05-01

322

Horizontal meridional thermospheric winds over King George Island, Antarctica, during the June 1991 Geomagnetic storm  

NASA Astrophysics Data System (ADS)

Diurnal variations of the magnetic meridional component of the thermospheric neutral wind have been derived from both a servo model based algorithm with ionosonde data input, and the HWM-90 empirical wind model for the 4-6 and 11-13 June 1991 geomagnetic storm at King George Island (62.2°S, 58.8°W). While the HWM-90 winds are predominantly equatorward, the servo model winds are predominantly poleward during the storm, with especially strong poleward winds in the pre-noon hours. Such strong poleward winds are not expected to occur during a major storm at such a low geomagnetic latitude (51.4°S), which is equatorward of direct ion drag forcing by magnetospheric convection electric fields. We speculate that this atypical thermospheric wind response may be associated with particle heating in the South Atlantic Anomaly.

Arriagada, M. A.; Foppiano, A. J.; Buonsanto, M. J.

1998-06-01

323

Making Summer Count: How Summer Programs Can Boost Children's Learning  

ERIC Educational Resources Information Center

During summer vacation, many students lose knowledge and skills. By the end of summer, students perform, on average, one month behind where they left off in the spring. Participation in summer learning programs should mitigate learning loss and could even produce achievement gains. Indeed, educators and policymakers increasingly promote summer

McCombs, Jennifer Sloan; Augustine, Catherine; Schwartz, Heather; Bodilly, Susan; McInnis, Brian; Lichter, Dahlia; Cross, Amanda Brown

2012-01-01

324

Global simulation of EMIC wave excitation during the 21 April 2001 storm from coupled RCM-RAM-HOTRAY modeling  

NASA Astrophysics Data System (ADS)

The global distribution and spectral properties of electromagnetic ion cyclotron (EMIC) waves in the He+ band are simulated for the 21 April 2001 storm using a combination of three different codes: the Rice Convection Model, the Ring current-Atmospheric interactions Model, and the HOTRAY ray tracing code (incorporated with growth rate solver). During the storm main phase, injected ions exhibit a non-Maxwellian distribution with pronounced phase space density minima at energies around a few keV. Ring current H+ injected from the plasma sheet provides the source of free energy for EMIC excitation during the storm. Significant wave gain is confined to a limited spatial region inside the storm time plume and maximizes at the eastward edge of the plume in the dusk and premidnight sector. The excited waves are also able to resonate and scatter relativistic electrons, but the minimum electron resonant energy is generally above 3 MeV.

Chen, Lunjin; Thorne, Richard M.; Jordanova, Vania K.; Wang, Chih-Ping; Gkioulidou, Matina; Lyons, Larry; Horne, Richard B.

2010-07-01

325

Role of model resolution and microphysical properties in simulating flash flood induce storms  

NASA Astrophysics Data System (ADS)

Flash flood induce storms are mainly of convective 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 storms, 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 storms 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 convective 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 convection 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.

Bartsotas, Nikolaos; Solomos, Stavros; Nikolopoulos, Efthymios I.; Anagnostou, Emmanouil; Kallos, George

2013-04-01

326

Asian Summer Monsoon Intraseasonal Variability in General Circulation Models  

SciTech Connect

The goals of this report are: (1) Analyze boreal summer Asian monsoon intraseasonal variability general circulation models--How well do the models represent the eastward and northward propagating components of the convection 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.

Sperber, K R; Annamalai, H

2004-02-24

327

Evidence for potential and inductive convection during intense geomagnetic events using normalized superposed epoch analysis  

NASA Astrophysics Data System (ADS)

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> <div class="credits"> <p class="dwt_author">Katus, Roxanne M.; Liemohn, Michael W.; Gallagher, Dennis L.; Ridley, Aaron; Zou, Shasha</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">328</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2005IAUS..226....3L"> <span id="translatedtitle">Research on Historical Records of Geomagnetic <span class="hlt">Storms</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">In recent times, there has been keen interest in understanding Sun-Earth connection events, such as solar flares, CMEs and concomitant magnetic <span class="hlt">storms</span>. Magnetic <span class="hlt">storms</span> are the most dramatic and perhaps important component of space weather effects on Earth. Super-intense magnetic <span class="hlt">storms</span> (defined here as those with Dst < -500 nT, where Dst stands for the disturbance <span class="hlt">storm</span> time index that measures the strength of the magnetic <span class="hlt">storm</span>) although relatively rare, have the largest societal and technological relevance. Such <span class="hlt">storms</span> can cause life-threatening power outages, satellite damage, communication failures and navigational problems. However, the data for such magnetic <span class="hlt">storms</span> is rather scarce. For example, only one super-intense magnetic <span class="hlt">storm</span> has been recorded (Dst=-640 nT, March 13, 1989) during the space-age (since 1958), although such <span class="hlt">storms</span> may have occurred many times in the last 160 years or so when the regular observatory network came into existence. Thus, research on historical geomagnetic <span class="hlt">storms</span> can help to create a good data base for intense and super-intense magnetic <span class="hlt">storms</span>. From the application of knowledge of interplanetary and solar causes of <span class="hlt">storms</span> gained from the spaceage observations applied to the super-intense <span class="hlt">storm</span> of September 1-2, 1859, it has been possible to deduce that an exceptionally fast (and intense) magnetic cloud was the interplanetary cause of this geomagnetic <span class="hlt">storm</span> with a Dst -1760 nT, nearly 3 times as large as that of March 13, 1989 super-intense <span class="hlt">storm</span>. The talk will focus on super-intense <span class="hlt">storms</span> of September 1-2, 1859, and also discuss the results in the context of some recent intense <span class="hlt">storms</span>.</p> <div class="credits"> <p class="dwt_author">Lakhina, G. S.; Alex, S.; Tsurutani, B. T.; Gonzalez, W. D.</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">329</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2011AGUFMNH51C..03H"> <span id="translatedtitle">Mesoscale aspects of <span class="hlt">storms</span> producing floods over regions of arid mountainous terrain</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">We have used the TRMM satellite's Precipitation Radar (PR) to develop a climatology of extreme <span class="hlt">convection</span> in the regions of the Andes and Himalayas. This work shows that intense <span class="hlt">convection</span> often occurs in arid regions but does not usually produce large amounts of rain. Large quantities of rain falling in mountainous regions is associated with the <span class="hlt">convective</span> systems that have the greatest horizontal scales. When such wide systems occur over arid mountains, they can produce lethal floods. The Pakistan flood of 2010 is a case in point. Wide <span class="hlt">convective</span> systems with large stratiform components became situated over the arid mountains of that region, with the result of the Indus River overflowed with disastrous consequences over a huge area. The potential of heavy rain in the region could have been inferred from the forecast synoptic-scale circulation, which indicated the occurrence of a great buildup of moisture in the region. Although the synoptic conditions were well forecast, that information alone was insufficient for predicting the flood conditions. It would have been necessary to anticipate also the mesoscale structure of the <span class="hlt">storms</span>. Our TRMM satellite climatology of rainstorm structures in this region indicated that the mesoscale <span class="hlt">convective</span> rainstorms responsible for the floods were of a type that does not normally occur in this region. Rather, this type of <span class="hlt">storm</span> usually occurs and produces copious monsoon rain far to the east, over the mountains and wetlands of northeastern India and Bangladesh. In this event, catastrophic runoff and flooding resulted as these rainstorms occurred far to the west of where they usually occur, over an arid and mountainous region unaccustomed to such <span class="hlt">storms</span>. This study indicates that taking into account the mesoscale structures of the cloud systems as well as the synoptic conditions in which they are embedded is essential for forecasting floods in this region of complex terrain.</p> <div class="credits"> <p class="dwt_author">Houze, R.; Romatschke, U.; Rasmussen, K. L.</p> <p class="dwt_publisher"></p> <p class="publishDate">2011-12-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">330</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ucar.edu/learn/1_1_2_7t.htm"> <span id="translatedtitle">Atmospheric Processes--<span class="hlt">Convection</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://nsdl.org/nsdl_dds/services/ddsws1-1/service_explorer.jsp">NSDL National Science Digital Library</a></p> <p class="result-summary">This activity begins with an explanation of the heat transfer process of <span class="hlt">convection</span>, the transfer of heat by the actual movement of the heated material. In the activity, students observe <span class="hlt">convective</span> currents in water and learn that air can behave as as a fluid.</p> <div class="credits"> <p class="dwt_author"></p> <p class="dwt_publisher"></p> <p class="publishDate">2010-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">331</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=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> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">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> <div class="credits"> <p class="dwt_author">Sandahl, I.; Eliasson, L.; Pellinen-Wannberg, A. (Swedish Inst. of Space Physics, Kiruna (Sweden)); Rostoker, G. (Univ. of Alberta, Edmonton (Canada)); Block, L.P. (Royal Inst. of Tech., Stockholm (Sweden)); Erlandson, R.E. (Johns Hopkins Univ., Laurel, MD (United States)); Friis-Christensen, E. (Danish Meteorological Inst., Copenhagen (Denmark)); Jacobsen, B. (Univ. of Oslo (Norway)); Luehr, H. (Technischen Univ., Braunschweig (West Germany)); Murphree, J.S. (Univ. of Calgary, Alberta (Canada))</p> <p class="dwt_publisher"></p> <p class="publishDate">1990-05-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">332</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2003EAEJA....12042B"> <span id="translatedtitle">Mediterranean <span class="hlt">summer</span> climate and the monsoon regimes</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The Authors examine the general features of climate of the Mediterranean Region, i.e. its variability and trends in the last 40 years, and the teleconnections between Mediterranean climate and the global climate, using zonal and global indices. In particular they focus the attention on the analysis of the <span class="hlt">summer</span> Mediterranean climate, and its variability and connection with the <span class="hlt">summer</span> monsoon regimes. Several subregions can be distinguished in the Mediterranean for each season, and the occurrence of Mediterranean Oscillation is evident between West and East sub-basins. Precipitation and SLP fields in the Eastern basin are shown to be correlated with Mediterranean Oscillation. A total decrease of precipitation has been detected in last few years, although there are some very intense. During winter a fundamental role is played by NAO index, which, influencing the <span class="hlt">storm</span> tracks coming from the Atlantic and passing over the Mediterranean and North Europe, it has a major role in the precipitation patterns over the Region. Moreover, temperature analysis over the last 40 years in the Mediterranean shows a distinct warming, in agreement with the pattern over North Emisphere and NAO index fluctuations. During <span class="hlt">summer</span> the Hadley cell extend further northwards, influencing the Mediterranean climate, and there is evidence of a possible teleconnection with the Asian Monsoon, and the Sahel precipitation (and related Hadley cell): the SLP field in the Eastern Mediterranean is inversely correlated with those two precipitation indices, while it is positively correlated with the pressure in the Western Mediterranean. Leading mechanisms of interaction between Mediterranean <span class="hlt">summer</span> rainfall and SLP patterns and precipitation indices associated with monsoon regimes are stressed out and investigated, as well as the influence of the position and strength of the Hadley cell, by means of both statistical and dynamical analytical arguments. A modeling study has been carried out in order to study the variations and the anomalies in the recent Mediterranean <span class="hlt">summer</span> precipitation patterns, consisting of two main phases. In the first phase, a numerical regional atmospheric model has been used to downscale the NCEP/NCAR reanalyses, showing a good agreement between model simulations and observations, proving the capability of the modeling tool. During the second phase, following and extending recent experiences the numerical model has been used to identify the features and extent of the impacts of the location and strength of the West Africa <span class="hlt">summer</span> monsoon - therefore the regional Hadley cell - to the Mediterranean climate, by selectively modifying the main forcing of that tropical circulation, i.e. the Gulf of Guinea sea surface temperatures.</p> <div class="credits"> <p class="dwt_author">Baldi, M.; Crisci, A.; Dalu, G. A.; Maracchi, G.; Meneguzzo, F.; Pasqui, M.</p> <p class="dwt_publisher"></p> <p class="publishDate">2003-04-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">333</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.meted.ucar.edu/mesoprim/severe2"> <span id="translatedtitle">Severe <span class="hlt">Convection</span> II: Mesoscale <span class="hlt">Convective</span> Systems</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://nsdl.org/nsdl_dds/services/ddsws1-1/service_explorer.jsp">NSDL National Science Digital Library</a></p> <p class="result-summary">Mesoscale <span class="hlt">convective</span> systems occur worldwide and year-round and are accompanied by the potential for severe weather and flooding. This module in the Mesoscale Primer series describes typical system evolution by examining squall line, bow echo, and MCC characteristics throughout their life cycles. This newly updated module includes more material on tropical squall lines, MCC, and on the ability of the NWP to predict <span class="hlt">convective</span> systems. Like other core modules in the Mesoscale Primer, this module starts with a forecast scenario and concludes with a final exam. Rich graphics, audio narration, and frequent interactions enhance the learning experience.</p> <div class="credits"> <p class="dwt_author">Spangler, Tim</p> <p class="dwt_publisher"></p> <p class="publishDate">2004-09-24</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">334</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ars.usda.gov/research/publications/Publications.htm?seq_no_115=133256"> <span id="translatedtitle">ESTIMATING PARAMETERS FOR CHARACTERIZING TIMES BETWEEN <span class="hlt">STORMS</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ars.usda.gov/services/TekTran.htm">Technology Transfer Automated Retrieval System (TEKTRAN)</a></p> <p class="result-summary">Characterization and estimation of times between <span class="hlt">storms</span> are needed for stochastic <span class="hlt">storm</span> simulation, drought studies, etc. An exploratory investigation into practical estimation of two characterization parameters was conducted using regression equations - critical duration (CD, minimum dry time betw...</p> <div class="credits"> <p class="dwt_author"></p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">335</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ntis.gov/search/product.aspx?ABBR=PB185314"> <span id="translatedtitle">Selected Urban <span class="hlt">Storm</span> Water Runoff Abstracts.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ntis.gov/search/index.aspx">National Technical Information Service (NTIS)</a></p> <p class="result-summary">The publication contains abstracts summarizing articles from a variety of technical publications, covering the subjects of urban runoff, <span class="hlt">storm</span> water discharge, <span class="hlt">storm</span> sewers, and combined sewers--together constituting 'the problem of urban drainage'. (Auth...</p> <div class="credits"> <p class="dwt_author"></p> <p class="dwt_publisher"></p> <p class="publishDate">1969-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">336</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2012cosp...39.1044L"> <span id="translatedtitle">On the interplanetary phenomenon, geomagnetic and ionospheric response associated with the <span class="hlt">storm</span> of July 8, 1975 in the East Asian sector</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">An investigation of the moderate geomagnetic <span class="hlt">storm</span> of July 8, 1975 (Dstmin =-60 nT) and its associated ionospheric <span class="hlt">storm</span> is presented. Available results show that the <span class="hlt">storm</span> was a double step <span class="hlt">storm</span> with the first Dstmin resulting mainly from ring current injection due to increase in solar wind density while magnetospheric <span class="hlt">convection</span> electric field played the leading role in the development of the second Dstmin . The analysis of the interplanetary and foF2 data obtained from ionosonde stations in East Asian longitudinal sector show that the appearance of positive <span class="hlt">storm</span> before the beginning of the geomagnetic disturbance in the mid-latitudes and the occurrence of strong negative phase at the low latitude station of Manila is due to the penetration of interplanetary electric field. Furthermore, obtainable results presented ionospheric response features that bear similarity in form and magnitude with those that are due to intense <span class="hlt">storms</span>. This suggests that a moderate <span class="hlt">storm</span> is capable of generating ionospheric <span class="hlt">storms</span> which are of comparable magnitude with those resulting from intense geomagnetic <span class="hlt">storms</span>.</p> <div class="credits"> <p class="dwt_author">Lawal, Hammed; Chukwuma, Victor</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-07-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">337</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2010EGUGA..1210827V"> <span id="translatedtitle"><span class="hlt">Storm</span> Effects on Net Ecosystem Productivity in Boreal Forests</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Regional carbon budgets are to some extent determined by disturbance in ecosystems. Disturbance is believed to be partly responsible for the large inter-annual variability of the terrestrial carbon balance. When neglecting anthropogenic disturbance, forest fires have been considered the most important kind of disturbance. However, also insect outbreaks and wind-throw may be major factors in regional carbon budgets. The effects of wind-throw on CO2 fluxes in boreal forests are not well known due to lack of data. Principally, the reduced carbon sequestration capacity, increased substrate availability and severe soil perturbation following wind-throw are expected to result in increased CO2 fluxes from the forest to the atmosphere. In January 2005, the <span class="hlt">storm</span> Gudrun hit Sweden, which resulted in approx. 66 × 106m3<span class="hlt">storm</span>-felled stem wood distributed over an area of approx. 272 000 ha. Eddy covariance flux measurements started at <span class="hlt">storm</span>-felled areas in Asa and Toftaholm in central Sweden during <span class="hlt">summer</span> 2005. Data from the first months suggests increased CO2 fluxes by a factor of 2.5-10, as compared to normal silviculture (clear-cutting). An important question is how long such enhanced CO2 fluxes persist. The BIOME-BGC model will be calibrated against measured CO2 fluxes from both sites for 2005 through 2009. Modeled data will be used to fill gaps in the data sets and annual carbon balances will be calculated. Data from Asa and Toftaholm will be presented at the conference.</p> <div class="credits"> <p class="dwt_author">Vestin, Patrik; Grelle, Achim; Lagergren, Fredrik; Hellström, Margareta; Langvall, Ola; Lindroth, Anders</p> <p class="dwt_publisher"></p> <p class="publishDate">2010-05-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">338</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2012cosp...39.1232M"> <span id="translatedtitle">Auroral Zone E-Region Electron Density Geomagnetic <span class="hlt">Storm</span> Enhancements Predicted by the Empirical <span class="hlt">STORM-E</span> Model</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">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 <span class="hlt">storm</span> enhancements to E-region electron densities. The empirical model is called <span class="hlt">STORM-E</span>. 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 um channel limb radiance measurements. The <span class="hlt">storm</span>-time response of the NO+(v) 4.3 um VER is most sensitive to auroral particle precipitation. A statistical database of <span class="hlt">storm</span>-time to climatological quiet-time ratios of SABER-observed NO+(v) 4.3 um VER are fit to widely available geomagnetic indices using the theoretical framework of linear impulse-response theory. The <span class="hlt">STORM-E</span> model provides a dynamic <span class="hlt">storm</span>-time correction factor to adjust a known quiescent E-region electron density peak concentration for geomagnetic enhancements due to auroral particle precipitation. In this paper, the development of the E-region electron density <span class="hlt">storm</span>-time correction factor is described. The <span class="hlt">STORM-E</span> <span class="hlt">storm</span>-time correction factor is fit to a single geomagnetic index. There are four versions of the <span class="hlt">STORM-E</span> model. Each version is fit to one of the following indices: HP-, AE-, Ap-, or Dst. High-latitude incoherent scatter radar (ISR) E-region electron density measurements are compared to <span class="hlt">STORM-E</span> predictions for various geomagnetic <span class="hlt">storm</span> periods during solar cycle 23. These comparisons show that <span class="hlt">STORM-E</span> significantly improves the prediction of E-region electron density enhancements due to auroral particle precipitation, in comparison to the nominal International Reference Ionosphere (IRI) model or to the quiet-time baseline electron density concentrations measured by ISR. The version of the <span class="hlt">STORM-E</span> model based on the fit to the Ap-index is now incorporated into the 2012 release of the IRI.</p> <div class="credits"> <p class="dwt_author">Mertens, Christopher; Bilitza, Dieter; Xu, Xiaojing</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-07-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">339</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2008AdG....14..271D"> <span id="translatedtitle">Space <span class="hlt">storms</span> as natural hazards</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Eruptive activity of the Sun produces a chain of extreme geophysical events: high-speed solar wind, magnetic field disturbances in the interplanetary space and in the geomagnetic field and also intense fluxes of energetic particles. Space <span class="hlt">storms</span> can potentially destroy spacecrafts, adversely affect astronauts and airline crew and human health on the Earth, lead to pipeline breaking, melt electricity transformers, and discontinue transmission. In this paper we deal with two consequences of space <span class="hlt">storms</span>: (i) rise in failures in the operation of railway devices and (ii) rise in myocardial infarction and stroke incidences.</p> <div class="credits"> <p class="dwt_author">Dorman, L. I.; Ptitsyna, N. G.; Villoresi, G.; Kasinsky, V. V.; Lyakhov, N. N.; Tyasto, M. I.</p> <p class="dwt_publisher"></p> <p class="publishDate">2008-04-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">340</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2011AGUFM.A12A..01C"> <span id="translatedtitle">Effects of urban pollution on downwind <span class="hlt">storms</span>: An energetic perspective</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">In two previous studies. the effects of the Houston Metropolitan area on the characteristics and intensity of <span class="hlt">convection</span> and precipitation were investigated for events triggered by the sea-breeze circulation . Carrió et al (2010) isolated the effects of the land-use change and examined the indirect effects of urban pollution considering sources of varied intensity linked to sub-grid urban area fractions. The Regional Atmospheric Modeling System developed at Colorado State University (RAMS@CSU) was validated against radar observations for the case used as a benchmark for these sensitivity experiments. With regard to the aerosol effects, as other authors have also found, enhancing cloud condensation nuclei (CCN) can produce an invigoration of downwind <span class="hlt">convective</span> cells due to additional latent heat release. However, results showed an interesting non-monotonic behavior of <span class="hlt">convection</span> intensity and precipitation when more intense CCN surface sources were considered. A second study (Carrió et al, 2011) consisted of a large number of multi-grid simulations (more than one hundred) and varied <span class="hlt">convective</span> instability in addition to the intensity of urban pollution sources. The non-monotonic response was linked to the riming efficiency reduction of ice particles when aerosol concentrations are greatly enhanced. Therefore, a greater fraction of the ice-phase condensed water mass is transported out of the <span class="hlt">storm</span> as pristine ice crystals instead of being transferred to precipitating water species. Even though, Carrió et al, (2011) strongly supports the relationship between the behavior of the simulated precipitation and the aforementioned microphysical mechanism, the evidence could be considered somewhat "circumstantial". For that reason, the problem was revisited with a new modeling study that approaches it from a more energetic perspective. These new numerical experiments used RAMS@CSU coupled to the Town Energy Budget (TEB) urban model and a microphysical module that considers the explicit activation of CCN (and giant CCN), a bimodal representation of cloud droplets, and a bin-emulation approach for droplet collection, ice-particle riming, and sedimentation. Model outputs every 30s were used to analyze the (indirect) effects of urban pollution on the efficiency of microphysical processes leading to the generation of precipitation particles (involving ice-phase and warm rain), latent heat release rates, buoyancy, vertical momentum, as well as several integral quantities linked to the <span class="hlt">convective</span> cells simulated downwind of the urban complex. Results clearly support the explanations inferred in the previous study, show a non-monotony behavior of several macroscopic characteristics of the downwind <span class="hlt">convective</span> cells, and indicate that the expected increase of the particulate pollution is more likely to selectively enhance precipitation of <span class="hlt">convective</span> events characterized by higher instability and extreme precipitation events.</p> <div class="credits"> <p class="dwt_author">Carrio, G. G.</p> <p class="dwt_publisher"></p> <p class="publishDate">2011-12-01</p> </div> </div> </div> </div> <div id="filter_results_form" class="filter_results_form floatContainer" style="visibility: visible;"> <div style="width:100%" id="PaginatedNavigation" class="paginatedNavigationElement"> <a id="FirstPageLink" onclick='return showDiv("page_1");' href="#" title="First Page"> <img id="FirstPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.first.18x20.png" alt="First Page" /></a> <a id="PreviousPageLink" onclick='return showDiv("page_16");' href="#" title="Previous Page"> <img id="PreviousPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.previous.18x20.png" alt="Previous Page" /></a> <span id="PageLinks" class="pageLinks"> <span> <a onClick='return showDiv("page_1");' href="#">1</a> <a onClick='return showDiv("page_2");' href="#">2</a> <a onClick='return showDiv("page_3");' href="#">3</a> <a onClick='return showDiv("page_4");' 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onclick='return showDiv("page_25.0");' href="#" title="Last Page"> <img id="LastPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.last.18x20.png" alt="Last Page" /></a> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">341</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://learningcenter.nsta.org/product_detail.aspx?id=10.2505/4/tst05_072_04_37"> <span id="translatedtitle">Shell Creek <span class="hlt">Summers</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://nsdl.org/nsdl_dds/services/ddsws1-1/service_explorer.jsp">NSDL National Science Digital Library</a></p> <p class="result-summary">What would motivate high school students to donate valuable <span class="hlt">summer</span> vacation time to do science research?--the opportunity to make a difference! The Shell Creek Watershed Improvement Group (SCWIG) was formed to identify and promote needed conservation practices within a local watershed, and turned to the high school science department to help educate the public on water quality in the watershed and to establish a monitoring system that would be used to improve surface and groundwater quality. Since 2002, for the past three <span class="hlt">summers</span>, in this ongoing project, students collect water quality data and report their findings to the three involved community organizations.</p> <div class="credits"> <p class="dwt_author">Seier, Mark; Goedeken, Suzy</p> <p class="dwt_publisher"></p> <p class="publishDate">2005-04-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">342</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/55026251"> <span id="translatedtitle">Clearing the Martian air - The troubled history of dust <span class="hlt">storms</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">This note is an attempt to resolve some misconceptions regarding the historical record of the Martian atmospheric phenomena referred to as 'dust <span class="hlt">storms</span>,' but often called yellow <span class="hlt">storms</span>, yellow clouds, planetwide dust <span class="hlt">storms</span>, global dust <span class="hlt">storms</span>, great dust <span class="hlt">storms</span>, etc. The known frequency of planet-encircling <span class="hlt">storms</span> will be specifically addressed. Better knowledge of the sizes, frequencies, and locations of Martian</p> <div class="credits"> <p class="dwt_author">L. J. Martin</p> <p class="dwt_publisher"></p> <p class="publishDate">1984-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">343</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2013SpWea..11..214K"> <span id="translatedtitle">Probability of occurrence of extreme magnetic <span class="hlt">storms</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">calculate the probability of extreme magnetic <span class="hlt">storms</span> in the solar cycle 24, cumulative distribution functions are investigated using an 89 year list of magnetic <span class="hlt">storms</span> recorded at Kakioka Magnetic Observatory. It is found that the probability of occurrence of extreme magnetic <span class="hlt">storms</span> can be modeled as a function of maximum sunspot number of a solar cycle, and the probability of another Carrington <span class="hlt">storm</span> occurring within the next decade is estimated to be 4-6%.</p> <div class="credits"> <p class="dwt_author">Kataoka, Ryuho</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-05-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">344</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://pubs.er.usgs.gov/publication/70024674"> <span id="translatedtitle">ENSO and winter <span class="hlt">storms</span> in California</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p class="result-summary">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> <div class="credits"> <p class="dwt_author">Cayan, D. R.; Bromirski, P.</p> <p class="dwt_publisher"></p> <p class="publishDate">2003-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">345</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2010AGUFMAE31B..04K"> <span id="translatedtitle">Lightning Mapping and Electric Field Change Observations of a Stationary New Mexico <span class="hlt">Storm</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">On August 23, 2010 a classic airmass thunderstorm occurred over high plains immediately east of the Langmuir Laboratory mountaintop observatory in central New Mexico. The energetic <span class="hlt">storm</span> developed around 2:30 pm MDT (2030 UTC) and remained essentially stationary over its complete lifetime of about 2 hours. The complete sequence of lightning was recorded both by the 16-station Langmuir Laboratory Lightning Mapping Array (LMA) and by several electrostatic field change stations around and beneath the <span class="hlt">storm</span>. The LMA and Delta-E data are both of very high quality and sensitivity. In this initial study we report on the lightning-inferred electrical structure of the <span class="hlt">storm</span> and on estimated charging currents determined from a simple electrodynamic model of the <span class="hlt">storm</span>. The electric field change measurements, in combination with the detailed 3-D mapping results, can be used to determine the amounts of charge involved in individual strokes and parts of flashes for comparison and improvement of the modeling. The LMA data regularly detected isolated attempted breakdown events at repeated locations at mid- to high altitudes in the <span class="hlt">storm</span> that were clearly indicative of localized high-field regions. The attempted breakdown events were often exact pre-cursors of the initial breakdown of full-fledged IC flashes typically several seconds up to several tens of seconds later, but also often did not precurse a subsequent discharge. During both IC and CG flashes, numerous recoil-type, fast negative breakdown events were detected along otherwise undetected positive leader channels in the main, mid-level negative charge region. The localized fast events during IC flashes often repeatedly intensified in strength and number prior to upward negative leader K-events, and then temporarily ceased before starting up again prior to the next K-event. Many of the negative CG flashes in the <span class="hlt">storm</span> produced strokes with long continuing currents (CCs). The overall electric field changes and hence total 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> <div class="credits"> <p class="dwt_author">Krehbiel, P. R.; Rison, W.; Hunyady, S. J.; Edens, H. E.; Sonnenfeld, R. G.; Aulich, G. D.</p> <p class="dwt_publisher"></p> <p class="publishDate">2010-12-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">346</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2008JGRD..113.5201W"> <span id="translatedtitle">Relationships among Narrow Bipolar Events, ``total'' lightning, and radar-inferred <span class="hlt">convective</span> strength in Great Plains thunderstorms</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Narrow Bipolar Events (NBEs) are a recently discovered distinct class of intracloud lightning discharges whose associated processes produce the most powerful very high frequency (VHF) radiation observed from lightning. NBEs are thus the prime candidate for proposed satellite-based VHF global lightning mapping and <span class="hlt">storm</span> tracking missions. In this study, we offer a detailed evaluation of the Great Plains Los Alamos Sferic Array (LASA). We then statistically compare NBE rates to non-NBE lightning rates measured by both the LASA and the National Lightning Detection Network (NLDN) and to NEXRAD radar-inferred metrics of <span class="hlt">convective</span> strength for thunderstorms in the Great Plains from May to July 2005. We find strong correlations between total lightning rate and <span class="hlt">convective</span> strength, especially in terms of the height of 30 dBZ radar echo. However, we find much weaker correlations between NBE rate and non-NBE lightning rate and between NBE rate and radar-inferred <span class="hlt">convective</span> strength. Though NBEs occur in the same <span class="hlt">storms</span> as other lightning, they cluster more closely in both space and time and may be indicative of specific types of <span class="hlt">storms</span> and/or specific stages in <span class="hlt">convective</span> development. Indeed, we find that NBEs are more prevalent in, and perhaps indicative of, the strongest <span class="hlt">convection</span>. However, even the strongest <span class="hlt">convection</span> (as inferred by radar) does not always produce NBEs. We compare these results to past studies of NBEs which were based in Florida. We also briefly discuss the implications of these results for satellite-based VHF lightning detection.</p> <div class="credits"> <p class="dwt_author">Wiens, Kyle C.; Hamlin, Timothy; Harlin, Jeremiah; Suszcynsky, David M.</p> <p class="dwt_publisher"></p> <p class="publishDate">2008-03-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">347</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/26602623"> <span id="translatedtitle">Neural network prediction of a <span class="hlt">storm</span> surge</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">The occurrence of <span class="hlt">storm</span> surge does not only destroy the resident's lives, but also cause the severe flooding in coastal areas. Therefore, accurate prediction of <span class="hlt">storm</span> surge is an important task during the coming typhoon. Conventional numerical methods and experienced methods for <span class="hlt">storm</span> surge prediction have been developed in the past, but it is still a complex ocean engineering problem</p> <div class="credits"> <p class="dwt_author">T.-L. Lee</p> <p class="dwt_publisher"></p> <p class="publishDate">2006-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">348</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.gpo.gov:80/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> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2012&page.go=Go">Code of Federal Regulations, 2012 CFR</a></p> <p class="result-summary">...Shipping 7 2012-10-01 2012-10-01 false <span class="hlt">Storm</span> rails. 177.920 Section 177.920 Shipping...AND ARRANGEMENT Rails and Guards § 177.920 <span class="hlt">Storm</span> rails. Suitable <span class="hlt">storm</span> rails or hand grabs must be installed where...</p> <div class="credits"> <p class="dwt_author"></p> <p class="dwt_publisher"></p> <p class="publishDate">2012-10-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">349</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.gpo.gov:80/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> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2012&page.go=Go">Code of Federal Regulations, 2012 CFR</a></p> <p class="result-summary">...Shipping 4 2012-10-01 2012-10-01 false <span class="hlt">Storm</span> rails. 127.320 Section 127.320 Shipping...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 at...</p> <div class="credits"> <p class="dwt_author"></p> <p class="dwt_publisher"></p> <p class="publishDate">2012-10-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">350</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.gpo.gov:80/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> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2012&page.go=Go">Code of Federal Regulations, 2012 CFR</a></p> <p class="result-summary">...Shipping 4 2012-10-01 2012-10-01 false <span class="hlt">Storm</span> rails. 116.920 Section 116.920 Shipping...AND ARRANGEMENT Rails 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> <div class="credits"> <p class="dwt_author"></p> <p class="dwt_publisher"></p> <p class="publishDate">2012-10-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">351</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.gpo.gov:80/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> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2012&page.go=Go">Code of Federal Regulations, 2012 CFR</a></p> <p class="result-summary">...Shipping 7 2012-10-01 2012-10-01 false <span class="hlt">Storm</span> rails. 169.329 Section 169.329 Shipping...and Arrangement Rails and Guards § 169.329 <span class="hlt">Storm</span> rails. Suitable <span class="hlt">storm</span> rails or hand grabs must be installed where...</p> <div class="credits"> <p class="dwt_author"></p> <p class="dwt_publisher"></p> <p class="publishDate">2012-10-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">352</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.gpo.gov:80/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> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2011&page.go=Go">Code of Federal Regulations, 2011 CFR</a></p> <p class="result-summary">...Shipping 7 2011-10-01 2011-10-01 false <span class="hlt">Storm</span> rails. 169.329 Section 169.329 Shipping...and Arrangement Rails and Guards § 169.329 <span class="hlt">Storm</span> rails. Suitable <span class="hlt">storm</span> rails or hand grabs must be installed where...</p> <div class="credits"> <p class="dwt_author"></p> <p class="dwt_publisher"></p> <p class="publishDate">2011-10-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">353</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.gpo.gov:80/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> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2011&page.go=Go">Code of Federal Regulations, 2011 CFR</a></p> <p class="result-summary">...Shipping 7 2011-10-01 2011-10-01 false <span class="hlt">Storm</span> rails. 177.920 Section 177.920 Shipping...AND ARRANGEMENT Rails and Guards § 177.920 <span class="hlt">Storm</span> rails. Suitable <span class="hlt">storm</span> rails or hand grabs must be installed where...</p> <div class="credits"> <p class="dwt_author"></p> <p class="dwt_publisher"></p> <p class="publishDate">2011-10-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">354</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.gpo.gov:80/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> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2012&page.go=Go">Code of Federal Regulations, 2012 CFR</a></p> <p class="result-summary">... 4 2012-10-01 2012-10-01 false <span class="hlt">Storm</span> rails. 108.221 Section 108.221 Shipping...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 following locations: (a)...</p> <div class="credits"> <p class="dwt_author"></p> <p class="dwt_publisher"></p> <p class="publishDate">2012-10-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">355</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://weather.unisys.com/hurricane/atlantic/index.html"> <span id="translatedtitle">Atlantic Tropical <span class="hlt">Storm</span> Tracking by Year</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://nsdl.org/nsdl_dds/services/ddsws1-1/service_explorer.jsp">NSDL National Science Digital Library</a></p> <p class="result-summary">Visitors to this site can access information on tropical <span class="hlt">storms</span> and hurricanes in the Atlantic Ocean as far back as 1851. Information provided here includes a yearly map showing the tracks of all <span class="hlt">storms</span>, and individual maps for each <span class="hlt">storm</span>. The individual maps are accompanied by data tables that show latitude, longitude, wind speed, dates, and times.</p> <div class="credits"> <p class="dwt_author"></p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">356</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/56407956"> <span id="translatedtitle">The Available Potential Energy of <span class="hlt">Storms</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">The <span class="hlt">storm</span>'s available potential energy and its rate of change are derived for a vertically walled volume encircling the <span class="hlt">storm</span> and extending from the surface to the top of the atmosphere. The rate of change includes explicit expressions for the generation of the <span class="hlt">storm</span>'s available potential energy, for its conversion to kinetic energy, and for its change through boundary work</p> <div class="credits"> <p class="dwt_author">Donald R. Johnson</p> <p class="dwt_publisher"></p> <p class="publishDate">1970-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">357</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://docs.lib.noaa.gov/rescue/mwr/082-095/086/mwr-086-10-0397.pdf"> <span id="translatedtitle">THE BIRTHPLACE OF NORTH ATLANTIC TROPICAL <span class="hlt">STORMS</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Newly adjusted tracks of North Atlantic hurricanes and tropical <span class="hlt">storms</span> for 72 years provide a consistent set of data for examining the birthplaces of these <span class="hlt">storms</span>. For 59 years (1899-1957) of the record, portions of the adjusted <span class="hlt">storm</span> tracks from the point of origin of first closed circulation to the point of first hurricane intensity are presented. The origins show</p> <div class="credits"> <p class="dwt_author">WILLIAM H. HAGGARD</p> <p class="dwt_publisher"></p> <p class="publishDate">1958-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">358</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ars.usda.gov/research/publications/Publications.htm?seq_no_115=220341"> <span id="translatedtitle">Characterizing Times Between <span class="hlt">Storms</span> in Mountainous Areas</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ars.usda.gov/services/TekTran.htm">Technology Transfer Automated Retrieval System (TEKTRAN)</a></p> <p class="result-summary">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> <div class="credits"> <p class="dwt_author"></p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">359</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/22665893"> <span id="translatedtitle">Magneto-<span class="hlt">convection</span>.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary"><span class="hlt">Convection</span> is the transport of energy by bulk mass motions. Magnetic fields alter <span class="hlt">convection</span> via the Lorentz force, while <span class="hlt">convection</span> 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-<span class="hlt">convection</span> 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 <span class="hlt">convection</span> zone through the visible surface (and into the chromosphere and corona) has been modelled. Local, <span class="hlt">convectively</span> driven dynamo action has been studied. The alteration in the appearance of granules and the formation of pores and sunspots has been investigated. Magneto-<span class="hlt">convection</span> 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</p> <div class="credits"> <p class="dwt_author">Stein, Robert F</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-07-13</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">360</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://eric.ed.gov/?q=emerson&pg=5&id=EJ547287"> <span id="translatedtitle">Books for <span class="hlt">Summer</span> Reading.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p class="result-summary">|For educators' <span class="hlt">summer</span> reading enjoyment, "Kappan" editors recommend three books on nature (Robert Richardson's biography "Emerson: The Mind on Fire, William Cronin's edited book "Uncommon Ground: Rethinking the Human Place in Nature," and Gary Snyder's poetry volume "Mountain and Rivers Without End"). Also recommended are three culturally diverse…</p> <div class="credits"> <p class="dwt_author">Phi Delta Kappan, 1997</p> <p class="dwt_publisher"></p> <p class="publishDate">1997-01-01</p> </div> </div> </div> </div> <div id="filter_results_form" class="filter_results_form floatContainer" style="visibility: visible;"> <div style="width:100%" id="PaginatedNavigation" class="paginatedNavigationElement"> <a id="FirstPageLink" onclick='return showDiv("page_1");' href="#" title="First Page"> <img id="FirstPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.first.18x20.png" alt="First Page" /></a> <a id="PreviousPageLink" onclick='return showDiv("page_17");' href="#" title="Previous Page"> <img id="PreviousPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.previous.18x20.png" alt="Previous Page" /></a> <span id="PageLinks" class="pageLinks"> <span> <a onClick='return showDiv("page_1");' href="#">1</a> <a onClick='return showDiv("page_2");' 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src="http://www.science.gov/scigov/images/icon.next.18x20.png" alt="Next Page" /></a> <a id="LastPageLink" onclick='return showDiv("page_25.0");' href="#" title="Last Page"> <img id="LastPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.last.18x20.png" alt="Last Page" /></a> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">361</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://files.eric.ed.gov/fulltext/EJ792940.pdf"> <span id="translatedtitle">Best New <span class="hlt">Summer</span> Books</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p class="result-summary">|When a colleague and friend gives you a new kids' book and says, "You have to read this," you pay attention. That's why the author asked a team of top teachers and librarians to share new favorites for <span class="hlt">summer</span>. Here are their picks for every reader, each bearing a teachers' stamp of approval.|</p> <div class="credits"> <p class="dwt_author">Trierweiler, Hannah; Cleaver, Samantha</p> <p class="dwt_publisher"></p> <p class="publishDate">2007-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">362</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://digital.lib.muohio.edu/fs/"> <span id="translatedtitle">Mississippi Freedom <span class="hlt">Summer</span> Project</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://nsdl.org/nsdl_dds/services/ddsws1-1/service_explorer.jsp">NSDL National Science Digital Library</a></p> <p class="result-summary">The Mississippi Freedom <span class="hlt">Summer</span> Project website, from Miami University of Ohio, documents the history of 1964's "Freedom <span class="hlt">Summer</span>", which was when volunteers gathered at the former Western College for Women in order to be trained to register African-American voters in Mississippi. Three volunteers were subsequently murdered in Mississippi, and "these events called attention to racial inequality and served as a catalyst for change." The collection was created by a grant from the Ohio Humanities Council, the Miami University Libraries, and a generous grant from Catherine Ross-Loveland, a 1952 graduate of the Western College for Women. The materials here include over 765 documents related to the Freedom <span class="hlt">Summer</span>, including reports from the FBI about those involved with the activities around this form of civil rights activism and articles from the Ohio press about the civil rights movement in the South during that time. There are also 27 videos here from conversations and tours held on campus in 2004 to commemorate the 40th anniversary of the Freedom <span class="hlt">Summer</span>. The videos include walking tours of the Western College for Women and panel discussions about faith and activism. Overall, it's a tremendous collection and one that merits several visits.</p> <div class="credits"> <p class="dwt_author"></p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">363</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://imaging.cancer.govhttp://www.aapm.org/meetings/08SS/"> <span id="translatedtitle">2008 AAPM <span class="hlt">Summer</span> School</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.cancer.gov">Cancer.gov</a></p> <p class="result-summary">June 25, 2008 12:00 AM - June 27, 2008 12:00 AM Edwin Hornberger Conference Center Houston, TX + Add to Outlook Calendar The Physics and Applications of PET/CT Imaging Print This Page 2008 AAPM <span class="hlt">Summer</span> School News & Events</p> <div class="credits"> <p class="dwt_author"></p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">364</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://eric.ed.gov/?q=nutrition+AND+games+AND+children&pg=5&id=ED303256"> <span id="translatedtitle">Bright Beginnings: <span class="hlt">Summer</span> Kindergarten.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p class="result-summary">|The <span class="hlt">summer</span> kindergarten program described in this guide is designed to meet the needs of children according to their stages of development and experience. The curriculum grows out of children's interests, learning styles, strengths, and stages of development. Direct experiences though which children can explore and discover constitute the core of…</p> <div class="credits"> <p class="dwt_author">New York City Board of Education, Brooklyn, NY. Div. of Curriculum and Instruction.</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">365</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://eric.ed.gov/?q=Gulf+AND+Mexico&id=EJ898397"> <span id="translatedtitle">My <span class="hlt">Summer</span> Vacation</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p class="result-summary">|In this article, a science teacher from the Midwest reflects on her <span class="hlt">summer</span> vacation to the Gulf of Mexico. She felt that this vacation would help improve her teaching about the environmental problems in the gulf and elsewhere. After all, anyone can show photos of oil-laden birds and dead sea turtles and read news clips of a distant place, but to…</p> <div class="credits"> <p class="dwt_author">Galus, Pamela</p> <p class="dwt_publisher"></p> <p class="publishDate">2010-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">366</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://eric.ed.gov/?q=%22their+eyes+were+watching+god%22&id=EJ426984"> <span id="translatedtitle">Books for <span class="hlt">Summer</span> Reading.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p class="result-summary">|To help replenish educators' supply of ideas, "Kappan" editors suggest several books for <span class="hlt">summer</span> reading, including many noncurrent titles not specifically on education such as Peter Novick's "That Noble Dream," Joy Kogawa's "Obasan," Zora Neale Hurston's "Their Eyes Were Watching God," Kate Chopin's "The Awakening," Willa Cather's "My Antonia,"…</p> <div class="credits"> <p class="dwt_author">Phi Delta Kappan, 1991</p> <p class="dwt_publisher"></p> <p class="publishDate">1991-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">367</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://eric.ed.gov/?q=summer+AND+warmer&id=EJ733996"> <span id="translatedtitle">Active Healthy <span class="hlt">Summer</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p class="result-summary">|<span class="hlt">Summer</span> break is almost here for most elementary teachers and students. Warmer weather and additional free time to make choices create more opportunities to be physically active, whether home alone or out with friends and family. This article describes ways by which physical education specialists can encourage students' physical activity by…</p> <div class="credits"> <p class="dwt_author">Elliott, Eloise</p> <p class="dwt_publisher"></p> <p class="publishDate">2005-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">368</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://eric.ed.gov/?q=reading+AND+science+AND+content&pg=4&id=EJ988020"> <span id="translatedtitle"><span class="hlt">Summer</span> Reading That Inspires</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p class="result-summary">|Why did you decide on science as a career? For many, it was the inspiration of a mentor or model--an explorer who could communicate excitement and a sense of adventure to others. During the school year, teachers take on that role of motivator for students. But as they recharge over <span class="hlt">summer</span> break, it is great to treat themselves again to the…</p> <div class="credits"> <p class="dwt_author">Texley, Juliana</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">369</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://eric.ed.gov/?q=Highways&pg=6&id=EJ629349"> <span id="translatedtitle">Books for <span class="hlt">Summer</span> Reading.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p class="result-summary">Teachers and education professors suggest various nonfiction and fiction books for <span class="hlt">summer</span> reading enjoyment, from Robert Putnam's "Bowling Alone," C.A. Bowers's "Let Them Eat Data," and Larry McMurtry's "Roads: Driving America's Great Highways" to Kent Hauf's "Plainsong, J.M. Coetzee's "Disgrace," and Michael Cunningham's "The Hours." (MLH)</p> <div class="credits"> <p class="dwt_author">[Editors</p> <p class="dwt_publisher"></p> <p class="publishDate">2001-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">370</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://eric.ed.gov/?q=commercial+AND+fishing&pg=2&id=ED229179"> <span id="translatedtitle"><span class="hlt">Summer</span> Fish Camp.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p class="result-summary">|The booklet presents a description and illustrates, with photographs, the Eskimo lifestyle and the kinds of activities that occur at a <span class="hlt">summer</span> fish camp on the Yukon River. Eleven suggested activities are listed for the teacher to present when using the booklet. Activities include studying the map of Alaska; tracing the life cycle of the fish;…</p> <div class="credits"> <p class="dwt_author">Remick, Dennis; Pulu, Tupou L.</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">371</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://eric.ed.gov/?q=comic+AND+books+AND+reading&pg=3&id=EJ229313"> <span id="translatedtitle">Superheroes and <span class="hlt">Summer</span> Reading.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p class="result-summary">|To combat <span class="hlt">summer</span> learning loss among remedial readers, teachers and consultants in the Omaha, Nebraska, Title I program designed a series of comic-book reading units and mailed them to students' homes. Parents were pleased with the project and it appeared that less reading skill had been lost by September. (SJL)|</p> <div class="credits"> <p class="dwt_author">Meyer, Ron; Buckner, Joyce</p> <p class="dwt_publisher"></p> <p class="publishDate">1980-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">372</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://eric.ed.gov/?q=furlong&id=EJ773664"> <span id="translatedtitle">Use Your <span class="hlt">Summer</span> Wisely</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p class="result-summary">Academics welcome <span class="hlt">summer</span> with a collective sigh of relief. Finally they can get to those tasks that are nearly impossible to accomplish during a busy academic year: working on that manuscript, completing the revisions on an article, learning the new laboratory technique from the colleague across the hall. However, those going on the job market in…</p> <div class="credits"> <p class="dwt_author">Vick, Julie Miller; Furlong, Jennifer S.</p> <p class="dwt_publisher"></p> <p class="publishDate">2007-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">373</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/17823057"> <span id="translatedtitle">Consulting to <span class="hlt">summer</span> camps.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">There has been an increased need for consultation to <span class="hlt">summer</span> camps from the allied health/mental health fields because camps are available to children with medical and psychological illnesses. Factors in camp programs that are necessary for effective consultation and the various roles a consultant may serve within the camp community are discussed in this article. PMID:17823057</p> <div class="credits"> <p class="dwt_author">Ditter, Bob</p> <p class="dwt_publisher"></p> <p class="publishDate">2007-10-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">374</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://eric.ed.gov/?q=superheroes&pg=4&id=EJ229313"> <span id="translatedtitle">Superheroes and <span class="hlt">Summer</span> Reading.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p class="result-summary">To combat <span class="hlt">summer</span> learning loss among remedial readers, teachers and consultants in the Omaha, Nebraska, Title I program designed a series of comic-book reading units and mailed them to students' homes. Parents were pleased with the project and it appeared that less reading skill had been lost by September. (SJL)</p> <div class="credits"> <p class="dwt_author">Meyer, Ron; Buckner, Joyce</p> <p class="dwt_publisher"></p> <p class="publishDate">1980-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">375</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://eric.ed.gov/?q=%22rogers%22&pg=7&id=EJ703956"> <span id="translatedtitle">Books for <span class="hlt">Summer</span> Reading</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p class="result-summary">In this article, the author, Roger Soder, discusses past books he has read throughout the year on his own and with his book club. He also makes suggestions for <span class="hlt">summer</span> reading selections. He thanks valued and nearby colleagues and friends for blessing him with books of great wisdom throughout the year.</p> <div class="credits"> <p class="dwt_author">Soder, Roger</p> <p class="dwt_publisher"></p> <p class="publishDate">2004-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">376</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2011AGUFMSM41A2004K"> <span id="translatedtitle">Ion Temperature Maps of the Plasma Sheet During HSS-driven <span class="hlt">storms</span> Calculated from TWINS ENA Measurements</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">While geomagnetic <span class="hlt">storms</span> can be driven by interplanetary coronal mass ejections (ICMEs) and high speed streams (HSSs) in the solar wind, the magnetospheric response varies depending on the driver. For example, electron and ion temperatures measured at geosynchronous orbit increase during both types of <span class="hlt">storms</span>, but the temperature increase is much larger during HSS-driven <span class="hlt">storms</span> [Denton et al., 2006]. For HSS-driven <span class="hlt">storms</span>, ion temperatures measured at geosynchronous orbit increase sharply at the time of <span class="hlt">convection</span> onset and remain elevated for the duration of the HSS-driven event [Denton and Borovsky, 2008]. These hot ions are <span class="hlt">convected</span> to the inner magnetosphere where they can drive the ring current. An injection of hot ions to the inner magnetosphere can be seen during the 22 July 2009 HSS-driven event in ion temperature maps calculated using energetic neutral atom (ENA) measurements provided by the TWINS dual-spacecraft mission. We will present these ion temperature maps along with those from additional HSS-driven events. The two TWINS spacecraft provide excellent spatial and temporal coverage for the study of ion heating during HSS-driven <span class="hlt">storms</span>.</p> <div class="credits"> <p class="dwt_author">Keesee, A. M.; Scime, E. E.</p> <p class="dwt_publisher"></p> <p class="publishDate">2011-12-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">377</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2011AtmRe.102..343S"> <span id="translatedtitle">Electrification of particles in dust <span class="hlt">storms</span>: Field measurements during the monsoon period in Niger</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">On the first fortnight of June 2010, experiments were carried out at a millet field in Niger to address the electrification of soil particles under natural conditions. The experiments were conducted during a period of high wind erosion, resulting from the passage of mesoscale <span class="hlt">convective</span> systems (MCSs) which generate "walls" of dust passing through the Sahel. Soil particles are lifted from the ground by the stress exerted by the wind, with a threshold for emission that is particle size dependent. These particles then collide with other particles, leading to electrostatic charging of the particles. Soil samples of either positive or negative polarity were collected from the soil surface in 3 situations: 1) during "quiet" periods (far removed from a dust <span class="hlt">storm</span>), 2) immediately after a dust <span class="hlt">storm</span>, and 3) 12 h after a dust <span class="hlt">storm</span>. Our results show that immediately after a dust <span class="hlt">storm</span>, smaller particles are predominantly charged positive and larger particles are predominantly charged negative; this effect is still evident but smaller in magnitude 12 h after a dust <span class="hlt">storm</span>. This size dependence for the charge polarity is in apparent contradiction with previous investigations; we believe this contradiction is only apparent, because the very fine particles, which we cannot measure with our technique, are expected to be negatively charged. Our results are rationalized by combining a population balance model for charged species trapped in high energy states with the wind threshold for soil particle motion.</p> <div class="credits"> <p class="dwt_author">Sow, Mamadou; Crase, Emmanuel; Rajot, Jean Louis; Sankaran, R. Mohan; Lacks, Daniel J.</p> <p class="dwt_publisher"></p> <p class="publishDate">2011-11-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">378</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/3805259"> <span id="translatedtitle">Street <span class="hlt">Storm</span> Water Conveyance Capacity</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">The street hydraulic capacity to convey <span class="hlt">storm</span> water is dictated by the street gutter geometry and hydraulic characteristics. With the consideration of traffic safety, the street hydraulic conveyance capacity is also subject to a reduction defined by the water velocity and flow depth in the street gutter. In this study, the street hydraulic equa- tion is re-arranged to demonstrate that</p> <div class="credits"> <p class="dwt_author">James C. Y. Guo</p> <p class="dwt_publisher"></p> <p class="publishDate">2000-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">379</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/1604207"> <span id="translatedtitle">Desert <span class="hlt">Storm</span>: air assault communications</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">The development of the US Army's 101st Airborne Division (Air Assault) Signal Battalion's command and control communications system from base-camp communications system into a system that provided division offensive communications which spanned more than 1000 miles and supported air assault ground and air combat offense operations in Iraq during Operations Desert Shield and Desert <span class="hlt">Storm</span> is discussed. The forward operating</p> <div class="credits"> <p class="dwt_author">D. P. Salerno</p> <p class="dwt_publisher"></p> <p class="publishDate">1992-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">380</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ntis.gov/search/product.aspx?ABBR=ADA262078"> <span id="translatedtitle">Media and Operation Desert <span class="hlt">Storm</span>.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ntis.gov/search/index.aspx">National Technical Information Service (NTIS)</a></p> <p class="result-summary">What kind of a job did the news media do in covering Operation Desert <span class="hlt">Storm</span>. The Assistant secretary of Defense (Public Affairs), thinks they did just fine, citing public opinion polls that indicate the media's popularity rose after the war was over. But ...</p> <div class="credits"> <p class="dwt_author">R. B. Marvin</p> <p class="dwt_publisher"></p> <p class="publishDate">1992-01-01</p> </div> </div> </div> </div> <div id="filter_results_form" class="filter_results_form floatContainer" style="visibility: visible;"> <div style="width:100%" id="PaginatedNavigation" class="paginatedNavigationElement"> <a id="FirstPageLink" onclick='return showDiv("page_1");' href="#" title="First Page"> <img id="FirstPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.first.18x20.png" alt="First Page" /></a> <a id="PreviousPageLink" onclick='return showDiv("page_18");' href="#" title="Previous Page"> <img id="PreviousPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.previous.18x20.png" alt="Previous Page" /></a> <span id="PageLinks" class="pageLinks"> <span> <a onClick='return showDiv("page_1");' href="#">1</a> <a onClick='return showDiv("page_2");' href="#">2</a> <a onClick='return showDiv("page_3");' href="#">3</a> <a onClick='return showDiv("page_4");' 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onclick='return showDiv("page_25.0");' href="#" title="Last Page"> <img id="LastPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.last.18x20.png" alt="Last Page" /></a> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">381</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/43793115"> <span id="translatedtitle">A study of geomagnetic <span class="hlt">storms</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">The interplanetary energy flux is estimated on the basis of the Poynting flux and its variations with the rate of energy dissipation in terms of: (1) the ring-current particle injection, (2) Joule dissipation in the ionosphere, and (3) auroral particle injection for 15 major geomagnetic <span class="hlt">storms</span>. A relationship, in terms of the angle between the interplanetary magnetic field vector and</p> <div class="credits"> <p class="dwt_author">Paul Perreault; S.-I. Akasofu</p> <p class="dwt_publisher"></p> <p class="publishDate">1978-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">382</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/26601937"> <span id="translatedtitle">Distributions for <span class="hlt">storm</span> surge extremes</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">The present paper is an attempt to assess a variety of potential probabilistic models for the meteorologically driven <span class="hlt">storm</span> surge component of a long term water level observation record at Sandy Hook, New Jersey. Simple assumptions are made with regard to the record, and the fitting of the extreme values of the data are assessed graphically in observation space for</p> <div class="credits"> <p class="dwt_author">Todd L Walton</p> <p class="dwt_publisher"></p> <p class="publishDate">2000-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">383</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/6192418"> <span id="translatedtitle">Synthesis of <span class="hlt">Storm</span> Drainage Design</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary"><span class="hlt">Storm</span> drainage systems are typically designed to carry runoff away from areas where it is unwanted (such as parking lots and roadways), and the design discharge is generally accomplished by the application of Rational method. The Rational method assumes a linear relation between rainfall rate for the time of concentration of the watershed and peak instantaneous discharge. This study includes</p> <div class="credits"> <p class="dwt_author">Xing Fang; Om B Gharty Chhetri; David B. Thompson</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">384</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://video.nasa.gov/core-dl/423/0/593/432379061/2831/423/1501/ef8a9dc11cdd72b10649d6fc3fae6b52.mp4"> <span id="translatedtitle">The Radiation Belt <span class="hlt">Storm</span> Probes</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.nasa.gov/multimedia/videogallery/index.html">NASA Video Gallery</a></p> <p class="result-summary">The Radiation Belt <span class="hlt">Storm</span> 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 astronauts. The mission will explore space weather -- changes in Earth's space environment caused by the sun -- which can affect our technology.</p> <div class="credits"> <p class="dwt_author">gsfcvideo</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-08-09</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">385</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ntis.gov/search/product.aspx?ABBR=PB86226644"> <span id="translatedtitle">Hurricane Gloria's Potential <span class="hlt">Storm</span> Surge.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ntis.gov/search/index.aspx">National Technical Information Service (NTIS)</a></p> <p class="result-summary">Hurricane Gloria threatened residents of the New York City metropolitan area on Friday, September 27, 1985. Gloria was one of the strongest north atlantic hurricanes of the century, yet the area never received the full fury of the <span class="hlt">storm</span> due to the followi...</p> <div class="credits"> <p class="dwt_author">A. F. Gigi D. A. Wert</p> <p class="dwt_publisher"></p> <p class="publishDate">1986-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">386</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ncifrederick.cancer.gov/News/Feature/StormPreparations.aspx"> <span id="translatedtitle">NCI at Frederick: <span class="hlt">Storm</span> Preparations</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.cancer.gov">Cancer.gov</a></p> <p class="result-summary">Hurricane Sandy is expected to affect the Frederick area with high winds and heavy rain early next week. The FNL Continuity of Operations Plan (COOP) has been activated and we are making preparations to deal with the effects of the <span class="hlt">storm</span>.</p> <div class="credits"> <p class="dwt_author"></p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">387</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2008AGUFM.H23E1024E"> <span id="translatedtitle">Analaysis of San Antonio River Floods Caused by Tropical <span class="hlt">Storm</span> Erin</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Tropical <span class="hlt">Storm</span> Erin started as a depression on August 14 2007. It deepened rapidly to evolve into a tropical <span class="hlt">storm</span> the morning of the 15th. It moved into Texas on the 16th with maximum sustained winds of 56 km/hr. The <span class="hlt">storm</span> produced 2-10 inches over south central Texas on August 16-17, 2008. The heaviest rainfall fell within a 6-hour period with totals in excess of 7.5 inches, as observed by the WSR-88D radar in New Braunfels, near San Antonio, TX. Average precipitation over the <span class="hlt">summer</span> provided sufficient moisture to cause Erin's precipitation to produce significant rapid runoff over portions of the San Antonio River. Radar rainfall data and a two-dimensional, physically-based, distributed-parameter hydrologic model were used to perform hydrometeorological analysis of this event. Hydrologic simulations on several sub-basins will be discussed.</p> <div class="credits"> <p class="dwt_author">Elhassan, A.; Sharif, H.</p> <p class="dwt_publisher"></p> <p class="publishDate">2008-12-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">388</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://data.giss.nasa.gov/stormtracks/"> <span id="translatedtitle">NASA: Atlas of Extratropical <span class="hlt">Storm</span> Tracks</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://nsdl.org/nsdl_dds/services/ddsws1-1/service_explorer.jsp">NSDL National Science Digital Library</a></p> <p class="result-summary">At this website, the NASA Goddard Institute for Space Studies offers an online atlas of fundamental information on extratropical <span class="hlt">storm</span> systems in the mid-latitude during the last half of the twentieth century. Users can find maps of <span class="hlt">storm</span> frequency and intensity and monthly and seasonal means as well as graphs of individual <span class="hlt">storm</span> paths and the most severe <span class="hlt">storms</span>. Researchers can download the <span class="hlt">storm</span> track data and a FORTRAN program used to extract time and geographic subsets of the database. The website adequately describes how the computations and plots were created.</p> <div class="credits"> <p class="dwt_author"></p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">389</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2003HyPr...17.1923B"> <span id="translatedtitle">Heavy metal concentrations during <span class="hlt">storm</span> events in a rehabilitated industrialized catchment</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Water quality data collected on a fortnightly or monthly basis are inadequate for assessment and modelling of many water quality problems as <span class="hlt">storm</span> event samples are underrepresented or missed. This paper examines the stormflow dynamics of heavy metals (Pb, Cu, Cd and Zn) in the Nant-y-Fendrod stream, South Wales, which has been affected by 250 years of metal smelting, followed by 35 years of landscape rehabilitation measures. For <span class="hlt">storm</span> events of contrasting (very dry and very wet) antecedent conditions in May 2000 and February 2001, respectively, temporal changes in streamwater heavy metal concentrations above and below an in-line flood detention lake are analysed. At the upstream site, peaks in total metal concentration were recorded on the rising limb for Pb (0·150 mg l-1) and Cu (0·038 mg l-1) but on the falling limb for Zn (1·660 mg l-1) and Cd (0·006 mg l-1) in the <span class="hlt">summer</span> 2000 <span class="hlt">storm</span> event, yielding clockwise and anticlockwise hysteretic loops respectively. In contrast, metal concentrations, although high throughout the winter <span class="hlt">storm</span> event, were diluted somewhat during the <span class="hlt">storm</span> peak itself. The Pb and Cu appear to be supplied by quickflow processes and transported in close association with fine sediment, whereas Zn and Cd are delivered to the channel and lake by slower subsurface seepage in dissolved form. In the winter 2001 event, antecedent soil moisture and shallow groundwater levels were anomalously high and seepage sources of dissolved metals dominated. Downstream of the lake, Pb and Cu levels and suspended sediment were high in the <span class="hlt">summer</span> <span class="hlt">storm</span>, but low in the winter <span class="hlt">storm</span>, suggesting retention with deposition of fine sediment in the lake during the latter. In the winter <span class="hlt">storm</span>, Zn and Cd levels were higher downstream than upstream of the lake, perhaps because of additional seepage inputs from the surrounding slopes, which failed to have an impact during <span class="hlt">summer</span>. An understanding of the complex interplay of antecedent soil moisture and the dynamics of subsurface seepage pathways in relation to the three-dimensional distribution of sources is important in modelling heavy metal fluxes and levels in contaminated urban catchments.</p> <div class="credits"> <p class="dwt_author">Blake, W. H.; Walsh, R. P. D.; Barnsley, M. J.; Palmer, G.; Dyrynda, P.; James, J. G.</p> <p class="dwt_publisher"></p> <p class="publishDate">2003-07-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">390</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.esf.edu/EFB/mitchell/Myron%20Ref/BioGeo.78.217.246.pdf"> <span id="translatedtitle">Solute Sources in Stream Water during Consecutive Fall <span class="hlt">Storms</span> in a Northern Hardwood Forest Watershed: A Combined Hydrological, Chemical and Isotopic Approach</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Understanding the effects of climate change including precipitation patterns has important implications for evaluating the\\u000a biogeochemical responses of watersheds. We focused on four <span class="hlt">storms</span> in late <span class="hlt">summer</span> and early fall that occurred after an exceptionally\\u000a dry period in 2002. We analyzed not only the influence of these <span class="hlt">storms</span> on episodic chemistry and the role of different water\\u000a sources in affecting</p> <div class="credits"> <p class="dwt_author">M. J. Mitchell; K. B. Piatek; S. Christopher; B. Mayer; C. Kendall; P. Mchale</p> <p class="dwt_publisher"></p> <p class="publishDate">2006-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">391</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2009pcms.confE..26S"> <span id="translatedtitle"><span class="hlt">Storms</span> of Mediterranean and Atlantic legends</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">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> <div class="credits"> <p class="dwt_author">Schoenenwald, N.; Tabeaud, M.</p> <p class="dwt_publisher"></p> <p class="publishDate">2009-09-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">392</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ntis.gov/search/product.aspx?ABBR=ADA231567"> <span id="translatedtitle"><span class="hlt">Convective</span> Scale Dynamics.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ntis.gov/search/index.aspx">National Technical Information Service (NTIS)</a></p> <p class="result-summary">A simplified discussion of the <span class="hlt">convective</span> process, the thunderstorm, and severe weather. Includes explanations of stability and the parcel theory. Describes thunderstorms, from garden variety to supercell. Tells how to recognize and forecast severe weathe...</p> <div class="credits"> <p class="dwt_author">J. R. Hedges</p> <p class="dwt_publisher"></p> <p class="publishDate">1990-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">393</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2000SoPh..192...91S"> <span id="translatedtitle">Realistic Solar <span class="hlt">Convection</span> Simulations</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">We report on realistic simulations of solar surface <span class="hlt">convection</span> that are essentially parameter-free, but include detailed physics in the equation of state and radiative energy exchange. The simulation results are compared quantitatively with observations. Excellent agreement is obtained for the distribution of the emergent continuum intensity, the profiles of weak photospheric lines, the p-mode frequencies, the asymmetrical shape of the mode velocity and intensity spectra, the p-mode excitation rate, and the depth of the <span class="hlt">convection</span> zone. We describe how solar <span class="hlt">convection</span> is non-local. It is driven from a thin surface thermal boundary layer where radiative cooling produces low entropy gas which forms the cores of the downdrafts in which most of the buoyancy work occurs. Turbulence and vorticity are mostly confined to the intergranular lanes and underlying downdrafts. Finally, we present some preliminary results on magneto-<span class="hlt">convection</span>.</p> <div class="credits"> <p class="dwt_author">Stein, Robert F.; Nordlund, Åke</p> <p class="dwt_publisher"></p> <p class="publishDate">2000-03-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">394</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/1999soho....9E..14S"> <span id="translatedtitle">Realistic Solar <span class="hlt">Convection</span> Simulations</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">We have performed essentially parameter free simulations with realistic physics of <span class="hlt">convection</span> near the solar surface. We summarize the physics that is included and compare the simulation results with observations. Excellent agreement is obtained for the depth of the <span class="hlt">convection</span> zone, the p-mode frequencies, the p-mode excitation rate, the distribution of the emergent continuum intensity, and the profiles of weak photospheric lines. We describe how solar <span class="hlt">convection</span> is non-local. It is driven from a thin surface thermal boundary layer where radiative cooling produces low entropy gas which forms the cores of the downdrafts in which most of the buoyancy work occurs. We show that turbulence and vorticity are mostly confined to the intergranular lanes and underlying downdrafts. Finally, we illustrate our current work on magneto-<span class="hlt">convection</span>.</p> <div class="credits"> <p class="dwt_author">Stein, Robert F.; Nordlund, Aake</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">395</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2004SPIE.5574..361D"> <span id="translatedtitle">Dust <span class="hlt">storm</span> monitoring: effects on the environment, human health, and potential security conflicts</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Monitoring dust <span class="hlt">storms</span> with recently available medium and moderate resolution satellites (Meris, Modis and SeaWiFS) is providing new global information regarding the sources, transportation tracks and affected areas. Saharan dust plumes reach the SE region of the United States and the Caribbean region in <span class="hlt">summer</span> and the Amazon basin in winter. Generally these Saharan plumes branch off in dust tracks along the North Atlantic reaching Western Europe as far north as the Scandinavian countries. Furthermore, dust <span class="hlt">storms</span> originating in the Eastern Sahara and Northern African deserts form dust plumes propagated by the Sirocco winds that, after crossing the Mediterranean Sea, affect Southern and Central Europe particularly during spring and <span class="hlt">summer</span>. Dust <span class="hlt">storms</span> originating in the Gobi and Taklamakan deserts blow in an easterly direction propagating dust plumes affecting Korea, Japan and reach the United States after crossing the Pacific Ocean. The large amount of cyclic deposition generated by dust <span class="hlt">storms</span> produces an environmental impact that causes the decay of coral reefs in the Caribbean, the origin and distribution of red tides and the disappearance of sea grasses. The relationship of dust plumes with the increasing number of asthma and allergy cases in the Caribbean correlates well with the appearance of similar cases in Europe and elsewhere during the mid 1980s. The recurrence presence of insecticides in regions where these products were banned long ago, or where they were never used, may be partly due to Saharan dust plumes. The loss of agricultural soil, literally blown away by dust <span class="hlt">storms</span> in the source areas, creates hardship, hunger and forced-migration. Dust <span class="hlt">storms</span> should be considered as an important security issue.</p> <div class="credits"> <p class="dwt_author">Davara, Fernando; de la Cruz, Antonio</p> <p class="dwt_publisher"></p> <p class="publishDate">2004-10-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">396</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/biblio/965133"> <span id="translatedtitle">The Effects of Aerosols on Intense <span class="hlt">Convective</span> Precipitation in the Northeastern U.S.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">A fully coupled meteorology-chemistry-aerosol mesoscale model (WRF-Chem) is used to assess the effects of aerosols on intense <span class="hlt">convective</span> precipitation over the northeastern United States. Numerical experiments are performed for three intense <span class="hlt">convective</span> <span class="hlt">storm</span> days and for two scenarios representing “typical” and “low” aerosol conditions. The results of the simulations suggest that increasing concentrations of aerosols can lead to either enhancement or suppression of precipitation. Quantification of the aerosol effect is sensitive to the metric used due to a shift of rainfall accumulation distribution when realistic aerosol concentrations are included in the simulations. Maximum rainfall accumulation amounts and areas with rainfall accumulations exceeding specified thresholds provide robust metrics of the aerosol effect on <span class="hlt">convective</span> precipitation. <span class="hlt">Storms</span> developing over areas with medium to low aerosol concentrations showed a suppression effect on rainfall independent of the meteorologic environment. <span class="hlt">Storms</span> developing in areas of relatively high particulate concentrations showed enhancement of rainfall when there were simultaneous high values of CAPE, relative humidity and wind shear. In these cases, elevated aerosol concentrations resulted in stronger updrafts and downdrafts and more coherent organization of <span class="hlt">convection</span>. For the extreme case, maximum rainfall accumulation differences exceeded 40 mm. The modeling results suggest that areas of the northeastern U.S. urban corridor that are close or downwind of intense sources of aerosols, could be more favorable for rainfall enhancement due to aerosols for the aerosol concentrations typical of this area.</p> <div class="credits"> <p class="dwt_author">Ntelekos, Alexandros A.; Smith, James S.; Donner, Leo J.; Fast, Jerome D.; Gustafson, William I.; Chapman, Elaine G.; Krajewski, Witold F.</p> <p class="dwt_publisher"></p> <p class="publishDate">2009-08-03</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">397</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://biology.mcgill.ca/faculty/lechowicz/articles/Arii&Lechowicz2007.pdf"> <span id="translatedtitle">Changes in understory light regime in a beech-maple forest after a severe ice <span class="hlt">storm</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">We assessed canopy openness (%) in an old-growth beech-maple forest immediately before and in the 3 years following a severe ice <span class="hlt">storm</span>. We estimated canopy openness using hemispherical photographs taken at a height of 0.6 m above the soil surface in 101 permanent plots. Mean canopy openness increased from a prestorm value of 7.7% to 16.6% in the <span class="hlt">summer</span> immediately</p> <div class="credits"> <p class="dwt_author">Ken Arii; Martin J. Lechowicz</p> <p class="dwt_publisher"></p> <p class="publishDate">2007-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">398</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2009GeoRL..3623805B"> <span id="translatedtitle">Weekly cycle of lightning: Evidence of <span class="hlt">storm</span> invigoration by pollution</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">We have examined summertime 1998-2009 U.S. lightning data from the National Lightning Detection Network (NLDN) to look for weekly cycles in lightning activity. As was found by Bell et al. (2008) for rain over the southeast U.S., there is a significant weekly cycle in afternoon lightning activity that peaks in the middle of the week there. The weekly cycle appears to be reduced over population centers. Lightning activity peaks on weekends over waters near the SE U.S. The statistical significance of weekly cycles over the western half of the country is generally small. We found no evidence of a weekly cycle of synoptic-scale forcing that might explain these patterns. The lightning behavior is entirely consistent with the explanation suggested by Bell et al. (2008) for the cycles in rainfall and other atmospheric data from the SE U.S., that aerosols can cause <span class="hlt">storms</span> to intensify in humid, <span class="hlt">convectively</span> unstable environments.</p> <div class="credits"> <p class="dwt_author">Bell, Thomas L.; Rosenfeld, Daniel; Kim, Kyu-Myong</p> <p class="dwt_publisher"></p> <p class="publishDate">2009-12-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">399</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ntis.gov/search/product.aspx?ABBR=AD757919"> <span id="translatedtitle"><span class="hlt">Summer</span> Thunderstorms over Southern California.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ntis.gov/search/index.aspx">National Technical Information Service (NTIS)</a></p> <p class="result-summary">Ten-day fire weather records from forestry lookouts in the southern California mountains are used to describe <span class="hlt">summer</span> thunderstorm activity. The distribution of thunderstorms during a typical season closely resembles rainy-day frequencies for <span class="hlt">summer</span> precip...</p> <div class="credits"> <p class="dwt_author">A. M. Tubbs</p> <p class="dwt_publisher"></p> <p class="publishDate">1972-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">400</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://home.ccr.cancer.gov/lop/Research/summer/lppastss.asp"> <span id="translatedtitle">LP Past <span class="hlt">Summer</span> Student Images</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.cancer.gov">Cancer.gov</a></p> <p class="result-summary">D  CCR Home   About CCR   CCR Intranet        Laboratory of Pathology LP Home Clinical Services Basic Sciences Training LP Staff Accessibility of Web Site LP Past <span class="hlt">Summer</span> Student Images Coming Soon Back to <span class="hlt">Summer</span> Student Home About CCR | Clinical</p> <div class="credits"> <p 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showDiv("page_12");' href="#">12</a> <a onClick='return showDiv("page_13");' href="#">13</a> <a onClick='return showDiv("page_14");' href="#">14</a> <a onClick='return showDiv("page_15");' href="#">15</a> <a onClick='return showDiv("page_16");' href="#">16</a> <a onClick='return showDiv("page_17");' href="#">17</a> <a onClick='return showDiv("page_18");' href="#">18</a> <a onClick='return showDiv("page_19");' href="#">19</a> <a onClick='return showDiv("page_20");' href="#">20</a> <a style="font-weight: bold;">21</a> <a onClick='return showDiv("page_22");' href="#">22</a> <a onClick='return showDiv("page_23");' href="#">23</a> <a onClick='return showDiv("page_24");' href="#">24</a> <a onClick='return showDiv("page_25");' href="#">25</a> </span> </span> <a id="NextPageLink" onclick='return showDiv("page_22");' href="#" title="Next Page"> <img id="NextPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.next.18x20.png" alt="Next Page" /></a> <a id="LastPageLink" onclick='return showDiv("page_25.0");' href="#" title="Last Page"> <img id="LastPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.last.18x20.png" alt="Last Page" /></a> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">401</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://learningcenter.nsta.org/product_detail.aspx?id=10.2505/4/ss04_027_09_12"> <span id="translatedtitle"><span class="hlt">Summer</span> by the Book</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://nsdl.org/nsdl_dds/services/ddsws1-1/service_explorer.jsp">NSDL National Science Digital Library</a></p> <p class="result-summary">By June, most teachers are more than ready to leave the classroom routine, but they are seldom able to leave their love of science behind. They travel, explore, and read, so that they can return in the fall better prepared to share science with students. Through reading, a teacher can spend valuable hours updating content background and methods, or simply refreshing the spirit. So, if your <span class="hlt">summer</span> plans include some stimulating reading, look no further.</p> <div class="credits"> <p class="dwt_author">Texley, Juliana</p> <p class="dwt_publisher"></p> <p class="publishDate">2004-07-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">402</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/55422663"> <span id="translatedtitle">The Oklahoma Squall Line of 19 May 1977. Part I: A Multiple Doppler Analysis of <span class="hlt">Convective</span> and Stratiform Structure</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">On 19 May 1977, a severe squall line formed and moved through the National Severe <span class="hlt">Storms</span> Laboratory observing network in Oklahoma, producing heavy rain, hail, strong winds, and tornadoes. The squall line is examined at two times: 1434 and 1502 CST. Doppler analysis of part of the squall line reveals four <span class="hlt">convective</span> cells in the line, developing cells ahead of</p> <div class="credits"> <p class="dwt_author">Cathy J. Kessinger; Peter S. Ray; Carl E. Hane</p> <p class="dwt_publisher"></p> <p class="publishDate">1987-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">403</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2005MAP....89..117Y"> <span id="translatedtitle">The East Asian <span class="hlt">summer</span> monsoon: an overview</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The present paper provides an overview of major problems of the East Asian <span class="hlt">summer</span> monsoon. The <span class="hlt">summer</span> monsoon system over East Asia (including the South China Sea (SCS)) cannot be just thought of as the eastward and northward extension of the Indian monsoon. Numerous studies have well documented that the huge Asian <span class="hlt">summer</span> monsoon system can be divided into two subsystems: the Indian and the East Asian monsoon system which are to a greater extent independent of each other and, at the same time, interact with each other. In this context, the major findings made in recent two decades are summarized below: (1) The earliest onset of the Asian <span class="hlt">summer</span> monsoon occurs in most of cases in the central and southern Indochina Peninsula. The onset is preceded by development of a BOB (Bay of Bengal) cyclone, the rapid acceleration of low-level westerlies and significant increase of <span class="hlt">convective</span> activity in both areal extent and intensity in the tropical East Indian Ocean and the Bay of Bengal. (2) The seasonal march of the East Asian <span class="hlt">summer</span> monsoon displays a distinct stepwise northward and northeastward advance, with two abrupt northward jumps and three stationary periods. The monsoon rain commences over the region from the Indochina Peninsula-the SCS-Philippines during the period from early May to mid-May, then it extends abruptly to the Yangtze River Basin, and western and southern Japan, and the southwestern Philippine Sea in early to mid-June and finally penetrates to North China, Korea and part of Japan, and the topical western West Pacific. (3) After the onset of the Asian <span class="hlt">summer</span> monsoon, the moisture transport coming from Indochina Peninsula and the South China Sea plays a crucial “switch” role in moisture supply for precipitation in East Asia, thus leading to a dramatic change in climate regime in East Asia and even more remote areas through teleconnection. (4) The East Asian <span class="hlt">summer</span> monsoon and related seasonal rain belts assumes significant variability at intraseasonal, interannual and interdecadal time scales. Their interaction, i.e., phase locking and in-phase or out-phase superimposing, can to a greater extent control the behaviors of the East Asian <span class="hlt">summer</span> monsoon and produce unique rythem and singularities. (5) Two external forcing i.e., Pacific and Indian Ocean SSTs and the snow cover in the Eurasia and the Tibetan Plateau, are believed to be primary contributing factors to the activity of the East Asian <span class="hlt">summer</span> monsoon. However, the internal variability of the atmospheric circulation is also very important. In particular, the blocking highs in mid-and high latitudes of Eurasian continents and the subtropical high over the western North Pacific play a more important role which is quite different from the condition for the South Asian monsoon. The later is of tropical monsoon nature while the former is of hybrid nature of tropical and subtropical monsoon with intense impact from mid-and high latitudes.</p> <div class="credits"> <p class="dwt_author">Yihui, Ding; Chan, Johnny C. L.</p> <p class="dwt_publisher"></p> <p class="publishDate">2005-06-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">404</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2007JASTP..69..151L"> <span id="translatedtitle">On a possible relationship between density depletions in the SAA region and <span class="hlt">storm</span>-enhanced densities in the conjugate hemisphere</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">During the great magnetic <span class="hlt">storm</span> of July 15, 2000, the ROCSAT-1 satellite with an orbital altitude of 640 km detected a large density depletion region at low latitudes (<35°) in the southern hemisphere while <span class="hlt">storm</span>-enhanced density (SED) was observed in the northern hemisphere. <span class="hlt">Convective</span> electric fields deduced from measurements of the ROCSAT-1 drift meters and retarding potential analyzer (RPA) indicate negligible electric fields in the eastern portion of the SED region where density enhancement was evident, suggesting a lack of ion upward motion at the equator of the SED longitudes. However, a localized electric field enhancement was observed in association with South Atlantic magnetic anomaly density structures (MADS) during the event. The zonal electric field component was eastward corresponding to radial <span class="hlt">convection</span>, and the radial electric field component on the magnetic meridional plane was outward corresponding to westward <span class="hlt">convection</span>. In general, both components of the observed <span class="hlt">convective</span> electric fields were enhanced inside the density depletion region and reduced inside the density enhancement. The electric field patterns are consistent with those arising from a circular region of flux tubes with enhanced conductance in the presence of a background electric field. The mapping of the MADS region and <span class="hlt">convective</span> electric fields from the southern hemisphere to the northern hemisphere suggests that these localized electric fields could drive ionospheric plasma from the conjugate MADS region to the SED at higher latitudes. We thus propose a new idea that the conjugate MADS region could be the plasma source for producing the SED.</p> <div class="credits"> <p class="dwt_author">Lin, C. S.; Yeh, H.-C.; Chao, C. K.</p> <p class="dwt_publisher"></p> <p class="publishDate">2007-02-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">405</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/biblio/970178"> <span id="translatedtitle">Early experience with red <span class="hlt">storm</span>.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">Red <span class="hlt">Storm</span> is a massively parallel processor. The Red <span class="hlt">Storm</span> design goals are: (1) Balanced system performance - CPU, memory, interconnect, and I/O; (2) Usability - functionality of hardware and software meets needs of users for Massively Parallel Computing; (3)S calability - system hardware and software scale, single cabinet system to {approx} 30,000 processor system; (4) reliability - machines tays up long enough between interrupts to make real progress on completing application run (at least 50 hours MTBI), requires full system RAS capability; (5) Upgradability - system can be upgraded with a processor swap and additional cabinets to 100T or greater; (6) red/black switching - capability to switch major portions of the machine between classified and unclassified computing environments; (7) space, power, cooling - high density, low power system; and (8) price/performance - excellent performance per dollar, use high volume commodity parts where feasible.</p> <div class="credits"> <p class="dwt_author">Kelly, Suzanne Marie; Ballance, Robert A.</p> <p class="dwt_publisher"></p> <p class="publishDate">2005-04-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">406</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://video.nasa.gov/core-dl/423/0/593/435476511/2841/423/1513/a081bff1a6bc370190259e5140028c81.mp4"> <span id="translatedtitle">Cloudsat Dissects Tropical <span class="hlt">Storm</span> Ileana</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.nasa.gov/multimedia/videogallery/index.html">NASA Video Gallery</a></p> <p class="result-summary">NASA's CloudSat satellite's Cloud Profiling Radar captured a sideways look across Tropical <span class="hlt">Storm</span> Ileana on Aug. 27 at 20:40 UTC. The colors indicate intensity of reflected radar energy. The blue areas along the top of the clouds indicate cloud ice, while the wavy blue lines on the bottom indicate intense rainfall. Credit: NASA/JPL/Colo. State Univ./NRL-Monterey</p> <div class="credits"> <p class="dwt_author">Karl Hille</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-08-29</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">407</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.nssl.noaa.gov/"> <span id="translatedtitle">NOAA's National Severe <span class="hlt">Storm</span> Laboratory</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://nsdl.org/nsdl_dds/services/ddsws1-1/service_explorer.jsp">NSDL National Science Digital Library</a></p> <p class="result-summary">The National Severe <span class="hlt">Storms</span> Laboratory serves the nation by working to improve the leadtime and accuracy of severe weather warnings and forecasts in order to save lives and reduce property damage. NSSL scientists are committed to their mission to understand the causes of severe weather and explore new ways to use weather information to assist National Weather Service forecasters and federal, university, and private sector partners.</p> <div class="credits"> <p class="dwt_author">Noaa</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">408</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/biblio/5376531"> <span id="translatedtitle"><span class="hlt">Storm</span> time heavy ion outflow at mid-latitudes</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">Local ionospheric observations with the Millstone Hill incoherent scatterradar reveal an upward ion bulk velocity in excess of 3 km s{sup {minus} 1} at 1,000 km altitude during the very large magnetic <span class="hlt">storm</span> on February 8, 1986. The upward flux of O{sup +} ions exceeded 3 {times} 10{sup 9} cm{sup {minus}2} s{sup {minus}1} at 42{degree} geodetic latitude (55{degree} {Lambda}) for a 3-hour period around 18 MLT during the event. Frictinal ion heating with ion temperatures in excess of 4,000 K at 500 km altitude was observed by the radar in the vicinity of the ion outflow event. Satellite observations place the ion outflow event within a region of intense ion and electron precipitation on field lines associated with the <span class="hlt">storm</span>-perturbed ring current. For a one-dimensional analysis of the observed plasma profiles, continuity considerations indicate a region of intense O{sup +} production (200 cm{sup {minus}3} s{sup {minus}1}) as well as significant upward acceleration (5-10 m s{sup {minus}2}) in the region between 600 km and 800 km altitude where the outflow approaches supersonic speed. Ionizing collisions involving fast backsplash neutral O atoms (Torr et al., 1974) produced by ring current heavy ion precipitation can provide sufficient upward momentum to account for the acceleration in the observed outflowing thermal O{sup +} fluxes. Alternatively, the outflow event can be explained in terms of a time-dependent diffusion process triggered by a sudden change in the frictional heating rate in the collision-dominated F region (St.-Maurice, 1989). The concurrence of rapid ion <span class="hlt">convection</span> and energetic ring current precipitation is unique at mid-latitudes during intense magnetic <span class="hlt">storms</span>. Under these conditions, the observations indicate that the mid-latitude ionosphere constitutes a significant source of upflowing thermal O{sup +} fluxes to the overlying magnetosphere.</p> <div class="credits"> <p class="dwt_author">Yeh, H.C.; Foster, J.C. (Massachusetts Inst. of Tech., Westford (USA))</p> <p class="dwt_publisher"></p> <p class="publishDate">1990-06-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">409</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/1999JGR...10412239V"> <span id="translatedtitle">Spatiotemporal activity of magnetic <span class="hlt">storms</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">We have constructed a data-derived model of the evolution of the spatial structure of the ring current geomagnetic signature during <span class="hlt">storms</span>. A spatially dependent generalization of the Dessler-Parker-Skopke relation has been derived to explain the spatial structure in the midlatitude magnetic fluctuations (MLMF) as observed by ground magnetometers. Such a relation is used as a basis for constructing solar-wind-driven, data-derived models of the MLMF. The model includes a coupling to the solar wind as the energy driver and also includes a nonlocal coupling as an explanation of the inhomogeneity in the energy density that appears in the ring current during the main phase of a <span class="hlt">storm</span>. Both linear and nonlinear models for the evolution of the spatial structure of the MLMF are constructed, and the nonlinear spatial model of the ring current produces better predictions than the linear one. This can be taken as an indication that during strong magnetic <span class="hlt">storms</span> the ring current evolves in a nonlinear fashion. The spatial data used in the generation of the models are rotated to a frame ``fixed'' with the ring current, and presure effects were accounted through a kinematic relation. The techniques developed in this paper are very general and can be used to study other systems that show spatial structure, such as the high-latitude current system.</p> <div class="credits"> <p class="dwt_author">Valdivia, J. A.; Vassiliadis, D.; Klimas, A.; Sharma, A. S.; Papadopoulos, K.</p> <p class="dwt_publisher"></p> <p class="publishDate">1999-06-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">410</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2009EGUGA..11.6860Y"> <span id="translatedtitle">Relationship between Northward and Eastward propagating ISOs in the south Asian <span class="hlt">summer</span> monsoon</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">South Asian <span class="hlt">summer</span> monsoon precipitation shows clear intraseasonal variation as large scale <span class="hlt">convective</span> anomalies propagates northward from the equator. This northward propagation is known to be accompanied by eastward propagation of <span class="hlt">convective</span> activity along the equator (MJO) through the Rossby wave propagation. However, it is found that the eastward and northward propagations are not coupled all the time partly because the timescale of northward propagation is relatively shorter than that of MJO propagation. When the MJO is weak or slows down, the independent northward propagation is often observed and it produces high-frequency intraseasonal variation of Asian <span class="hlt">summer</span> monsoon precipitation. Therefore, the Indian daily rainfall and MJO phases are related in a complex way. It seems that there is another mechanism to produce northward propagation of <span class="hlt">convective</span> activity other than Rossby wave propagation by the eastward moving MJO signal.</p> <div class="credits"> <p class="dwt_author">Yoo, J. H.; Yadav, R. K.; Kucharski, F.</p> <p class="dwt_publisher"></p> <p class="publishDate">2009-04-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">411</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2012RvGeo..50.4004Y"> <span id="translatedtitle"><span class="hlt">Convective</span> quasi-equilibrium</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The concept of <span class="hlt">convective</span> quasi-equilibrium (CQE) is a key ingredient in order to understand the role of deep moist <span class="hlt">convection</span> in the atmosphere. It has been used as a guiding principle to develop almost all <span class="hlt">convective</span> parameterizations and provides a basic theoretical framework for large-scale tropical dynamics. The CQE concept as originally proposed by Arakawa and Schubert (1974) is systematically reviewed from wider perspectives. Various interpretations and extensions of Arakawa and Schubert's CQE are considered both in terms of a thermodynamic analogy and as a dynamical balance. The thermodynamic interpretations can be more emphatically embraced as a homeostasis. The dynamic balance interpretations can be best understood by analogy with the slow manifold. Various criticisms of CQE can be avoided by taking the dynamic balance interpretation. Possible limits of CQE are also discussed, including the importance of triggering in many <span class="hlt">convective</span> situations, as well as the possible self-organized criticality of tropical <span class="hlt">convection</span>. However, the most intriguing aspect of the CQE concept is that in spite of many observational tests supporting and interpreting it in many different senses, it has never been established in a robust manner based on a systematic analysis of the cloud work function budget by observations as was originally defined.</p> <div class="credits"> <p class="dwt_author">Yano, J.-I.; Plant, R. S.</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-12-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">412</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/22665774"> <span id="translatedtitle">Anomalously weak solar <span class="hlt">convection</span>.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary"><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 ?. Within the wavenumber band ? < 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 ? < 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 <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> <div class="credits"> <p class="dwt_author">Hanasoge, Shravan M; Duvall, Thomas L; Sreenivasan, Katepalli R</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-06-04</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">413</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=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> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p class="result-summary"><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 ?. Within the wavenumber band ? < 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 ? < 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.</p> <div class="credits"> <p class="dwt_author">Hanasoge, Shravan M.; Duvall, Thomas L.</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">414</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/15644376"> <span id="translatedtitle"><span class="hlt">Convection</span> in containerless processing.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">Different containerless processing techniques have different strengths and weaknesses. Applying more than one technique allows various parts of a problem to be solved separately. For two research projects, one on phase selection in steels and the other on nucleation and growth of quasicrystals, a combination of experiments using electrostatic levitation (ESL) and electromagnetic levitation (EML) is appropriate. In both experiments, <span class="hlt">convection</span> is an important variable. The <span class="hlt">convective</span> conditions achievable with each method are compared for two very different materials: a low-viscosity, high-temperature stainless steel, and a high-viscosity, low-temperature quasicrystal-forming alloy. It is clear that the techniques are complementary when <span class="hlt">convection</span> is a parameter to be explored in the experiments. For a number of reasons, including the sample size, temperature, and reactivity, direct measurement of the <span class="hlt">convective</span> velocity is not feasible. Therefore, we must rely on computation techniques to estimate <span class="hlt">convection</span> in these experiments. These models are an essential part of almost any microgravity investigation. The methods employed and results obtained for the projects levitation observation of dendrite evolution in steel ternary alloy rapid solidification (LODESTARS) and quasicrystalline undercooled alloys for space investigation (QUASI) are explained. PMID:15644376</p> <div class="credits"> <p class="dwt_author">Hyers, Robert W; Matson, Douglas M; Kelton, Kenneth F; Rogers, Jan R</p> <p class="dwt_publisher"></p> <p class="publishDate">2004-11-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">415</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/49340798"> <span id="translatedtitle">Discontinuous Galerkin methods for modeling Hurricane <span class="hlt">storm</span> surge</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary"><span class="hlt">Storm</span> surge due to hurricanes and tropical <span class="hlt">storms</span> can result in significant loss of life, property damage, and long-term damage to coastal ecosystems and landscapes. Computer modeling of <span class="hlt">storm</span> surge can be used for two primary purposes: forecasting of surge as <span class="hlt">storms</span> approach land for emergency planning and evacuation of coastal populations, and hindcasting of <span class="hlt">storms</span> for determining risk, development</p> <div class="credits"> <p class="dwt_author">Clint Dawson; Ethan J. Kubatko; Joannes J. Westerink; Corey Trahan; Christopher Mirabito; Craig Michoski; Nishant Panda</p> <p class="dwt_publisher"></p> <p class="publishDate">2011-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">416</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2005JCli...18.1697S"> <span id="translatedtitle">Interannual and Interdecadal Variability of Thailand <span class="hlt">Summer</span> Monsoon Season.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary"><span class="hlt">Summer</span> monsoon rains are a critical factor in Thailand's water resources and agricultural planning and management. In fact, they have a significant impact on the country's economic health. Consequently, understanding the variability of the <span class="hlt">summer</span> monsoon rains over Thailand is important for instituting effective mitigating strategies against extreme rainfall fluctuations. To this end, the authors systematically investigated the relationships between <span class="hlt">summer</span> monsoon precipitation from the central and northern regions of Thailand and large-scale climate features. It was found that Pacific sea surface temperatures (SSTs), in particular, El Niño-Southern Oscillation (ENSO), have a negative relationship with the <span class="hlt">summer</span> monsoon rainfall over Thailand in recent decades. However, the relationship between <span class="hlt">summer</span> rainfall and ENSO was weak prior to 1980. It is hypothesized that the ENSO teleconnection depends on the SST configuration in the tropical Pacific Ocean, that is, an eastern Pacific-based El Niño pattern, such as is the case in most of the post-1980 El Niño events, tends to place the descending limb of the Walker circulation over the Thailand-Indonesian region, thereby significantly reducing <span class="hlt">convection</span> and consequently, rainfall over Thailand. It is believed that this recent shift in the Walker circulation is instrumental for the nonstationarity in ENSO-monsoon relationships in Thailand. El Niños of 1997 and 2002 corroborate this hypothesis. This has implications for monsoon rainfall forecasting and, consequently, for resources planning and management.</p> <div class="credits"> <p class="dwt_author">Singhrattna, Nkrintra; Rajagopalan, Balaji; Krishna Kumar, K.; Clark, Martyn</p> <p class="dwt_publisher"></p> <p class="publishDate">2005-06-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">417</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2009AGUFMSM14A..06B"> <span id="translatedtitle">Ring current behavior in weak and strong <span class="hlt">storm</span>: What controls a <span class="hlt">storm</span> size?</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The ring current (RC) exhibits different behavior during magnetospheric <span class="hlt">storms</span> depending on <span class="hlt">storm</span> strength and the <span class="hlt">storm</span> driver. Using energetic neutral atom (ENA) data and model results, we perform a comparative study of RC behavior during weak and strong <span class="hlt">storms</span> and try to find out what is the main factor that controls a <span class="hlt">storm</span> size. To study weak <span class="hlt">storms</span>, we use ENA data from Two Wide-angle Imaging Neutral-atom Spectrometers (TWINS) during solar minimum in 2008. The strong <span class="hlt">storm</span> RC is studied with IMAGE/HENA data near solar cycle maximum in 2000. To model RC and ENA emissions we use the Comprehensive Ring Current Model (CRCM). Based on our data-model comparative study, we examine the role of electric field shielding in RC asymmetry, the relation between ENA emissions from RC injections and low-altitude ENA emissions, and the location of total pressure peak during main phase and recovery phase for different types of <span class="hlt">storms</span>.</p> <div class="credits"> <p class="dwt_author">Buzulukova, N.; Fok, M. H.; Valek, P. W.; Goldstein, J.; McComas, D. J.; Brandt, P. C.</p> <p class="dwt_publisher"></p> <p class="publishDate">2009-12-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">418</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2010AdG....26...53S"> <span id="translatedtitle">Violent <span class="hlt">storms</span> within the Sea: dense water formation episodes in the NW Mediterranean</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Heat and water exchanges in the ocean occur almost exclusively at the surface. As water compressibility is very low, stratification of the fluid is expected and horizontal motion is predominant in the sea interior. Among the few processes that may introduce a vertical component in the water motion are those that increase surface water density by freezing, cooling or evaporation. Those processes triggering <span class="hlt">convective</span> motion are enhanced by cold surface air, dry wind and low solar radiation. Therefore, <span class="hlt">convective</span> cells are more likely to occur when the temperature of the air at the sea surface is lower than sea surface temperature. Conversely, rain, river runoff, solar heating, calm and condensation at surface enhance stratification. <span class="hlt">Convective</span> motion at sea has several scales ranging from few meters at the upper ocean, causing the surface mixed layer, to the entire water column, in what is known as deep <span class="hlt">convection</span>. Only few places in the world ocean are suitable for deep <span class="hlt">convection</span>, and only under particular weather conditions. In this paper, a brief review of the response to these particular conditions in the NW Mediterranean is presented in what is known as dense water formation. The violent sinking and spreading of water parcels that reach the deep sea floor in few hours is described. These are "hidden" mediterranean <span class="hlt">storms</span>, occurring under the sea surface, "on the other side of the mirror".</p> <div class="credits"> <p class="dwt_author">Salat, J.; Puig, P.; Latasa, M.</p> <p class="dwt_publisher"></p> <p class="publishDate">2010-07-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">419</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2009AGUFM.A44B..05C"> <span id="translatedtitle">Sea-breeze induced <span class="hlt">convection</span> over Houston: Sensitivity of Aerosol Indirect Effects to instability</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">This work is a follow-up to our previous study of the effects of the Houston, TX metropolitan area on the intensity of <span class="hlt">convection</span> and precipitation. Using RAMS coupled to the Town Energy Budget (TEB) urban model, we had examined the impact of urban growth on <span class="hlt">convection</span> using the Landsat Thematic Mapper National Land Cover Data (NLCD) corresponding to the years 1992, 2001 and 2006. We analyzed the impact on two distinct groups of simulated(and observed) <span class="hlt">convective</span> cells that developed on August 24 2000. The first group of <span class="hlt">storms</span> located southeast of the city and the second, occurred north of the city (downwind). For the first group, the effects of land-use on <span class="hlt">convection</span> and precipitation were dramatic and mainly linked to a monotonic increase in the intensity of the sea breeze due to the urban land-use change. The total volume of precipitation increased monotonically when increased city size was considered. Conversely, the <span class="hlt">storm</span> that developed north of the city was significantly perturbed by the enhanced concentrations of aerosols from the urban sources. In agreement with previous studies, enhancing CCN concentrations reduced the size of the liquid droplets, reduced collection, and increased the amount of supercooled liquid content. Therefore, <span class="hlt">convective</span> cells were intensified by enhanced latent heat of freezing. However, the effect on precipitation was not monotonic because as CCN concentrations are increased to large amounts, the efficiency of droplet collection and ice-phase riming is greatly reduced. As a result a large fraction of condensate is transported aloft as pristine ice crystals rather than forming large precipitation particles. In addition, the enhanced concentration of (smaller) pristine ice crystals transported to higher levels of the <span class="hlt">storm</span> enhances the optical thickness, area coverage and life time of cirrus-anvil clouds . In summary, aerosol pollution can intensify <span class="hlt">convective</span> cells downwind of the city due to additional latent heat release, but while modest increases in pollution can increase precipitation, large amounts of aerosol pollution can reduce precipitation. On-going research is examining how variations in <span class="hlt">convective</span> instability can modify the relative importance of these two opposing effects on precipitation for sea-breeze-induced <span class="hlt">storms</span> over an urban complex. In these experiments, both the strength of aerosol pollution and <span class="hlt">convective</span> instability are varied.</p> <div class="credits"> <p class="dwt_author">Carrio, G. G.; Cotton, W. R.</p> <p class="dwt_publisher"></p> <p class="publishDate">2009-12-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">420</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2004cosp...35.3049W"> <span id="translatedtitle">The thermospheric neutral wind response to geomagnetic <span class="hlt">storms</span>.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The Center for Integrated Space weather Modeling (CISM) suite of models was run recently to perform an end-to-end simulation of the solar-terrestrial environment. The Coupled Magnetosphere-Ionosphere Model (CMIT) is one of the models used in this run. CMIT has two components: the LFM global magnetosphere model and the Thermosphere-Ionosphere Nested Grid (TING) model. CMIT was driven by simulated solar wind data from the solar coronal and solar wind models. In this paper, we present the thermospheric neutral wind response to variations in the magnetospheric inputs under various solar wind conditions. It is found that: 1) During the IMF Bz southward period, the neutrals and ions were tightly coupled. The neutral winds followed the ion two cell-<span class="hlt">convection</span> pattern. Their speeds were greatly increased due to the enhanced ion drifts during the geomagnetic <span class="hlt">storm</span>. 2) During the Bz northward, By negative period, the ions and neutrals were less coupled. The enhanced F- region neutral temperature produced a strong pressure gradient force. Thus in this period F-region neutral winds were driven mostly by the pressure gradient force instead of the ion <span class="hlt">convection</span> pattern; 3) During the long period when IMF Bz was northward and By was close to zero the F region neutral winds weakened significantly. Features of semidiurnal tides were evident in the neutral wind circulation.</p> <div class="credits"> <p class="dwt_author">Wang, W.; Burns, A.; Killeen, T.; Wiltberger, M.; Solomon, S.</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div id="filter_results_form" class="filter_results_form floatContainer" style="visibility: visible;"> <div style="width:100%" id="PaginatedNavigation" class="paginatedNavigationElement"> <a id="FirstPageLink" onclick='return showDiv("page_1");' href="#" title="First Page"> <img id="FirstPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.first.18x20.png" alt="First Page" /></a> <a id="PreviousPageLink" onclick='return showDiv("page_20");' href="#" title="Previous Page"> <img id="PreviousPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.previous.18x20.png" alt="Previous Page" /></a> <span id="PageLinks" class="pageLinks"> <span> <a onClick='return showDiv("page_1");' 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showDiv("page_23");' href="#" title="Next Page"> <img id="NextPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.next.18x20.png" alt="Next Page" /></a> <a id="LastPageLink" onclick='return showDiv("page_25.0");' href="#" title="Last Page"> <img id="LastPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.last.18x20.png" alt="Last Page" /></a> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">421</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2008AGUFMOS41B1218L"> <span id="translatedtitle">Development of Three-Dimensional <span class="hlt">Storm</span> Surges/Tide Prediction System by Regional Ocean Modeling System (ROMS)</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Over the past 30 years, an average of 26 typhoons per year has originated in the northwestern Pacific Ocean, among which three on average have affected the Korean Peninsula. Typhoons are particularly frequent in <span class="hlt">summer</span> in the Pacific Ocean and can pass or make landfall on the Korean Peninsula, often causing serious damage to property in the coastal region. In this study, we developed three-dimensional <span class="hlt">Storm</span> surges/Tide prediction system based on ROMS (Regional Ocean Modeling System). ROMS is a free-surface, terrain-following, primitive equations ocean model widely used by the scientific community for a diverse range of applications. This prediction system covers 115°E, 20°N with 1/12° horizontal resolutions and 20 vertical layers including the Yellow Sea, East China Sea and the East Sea, marginal seas around Korea. The newly developed three-dimensional <span class="hlt">Storm</span> surges/Tide prediction system has been applied to hindcasting study for typhoon cases. Sea surface wind and pressure from the Korea Weather Research and Forecasting (KWRF) is used for forcing input of <span class="hlt">storm</span> surge/tide prediction system. In this model, the level of <span class="hlt">storm</span> surge calculated by the difference between tide level and sea level change caused by meteorological effects. The three-dimensional <span class="hlt">storm</span> surges/tide prediction system simulates very well the <span class="hlt">storm</span> surges/tide pattern around Korean Peninsular. The <span class="hlt">storm</span> surges were hindcasted using pressure and wind field of Typhoon. The result showed that the <span class="hlt">storm</span> surges by the three-dimensional model were in well agreement with the observed high <span class="hlt">storm</span> surges height in the coastal areas.</p> <div class="credits"> <p class="dwt_author">Lee, W.; You, S.; Moon, K.; Seo, J.; Kim, K.</p> <p class="dwt_publisher"></p> <p class="publishDate">2008-12-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">422</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/56330628"> <span id="translatedtitle">Nuclear Magnetohydrodynamic EMP, Solar <span class="hlt">Storms</span>, and Substorms</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">In addition to a fast electromagnetic pulse (EMP), a high altitude nuclear burst produces a relatively slow magnetohydrodynamic EMP (MHD EMP), whose effects are like those from solar <span class="hlt">storm</span> geomagnetically induced currents (SS-GIC). The MHD EMP electric field E≲10-1 V\\/m and lasts ≲102 sec, whereas for solar <span class="hlt">storms</span> E≳10-2 V\\/m and lasts ≳103 sec. Although the solar <span class="hlt">storm</span> electric field</p> <div class="credits"> <p class="dwt_author">Mario Rabinowitz; A. P. Sakis Meliopoulos; Elias N. Glytsis; George J. Cokkinides</p>