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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

Environmental conditions responsible for the type of precipitation in summer convective storms over Bulgaria  

NASA Astrophysics Data System (ADS)

Environmental conditions of 155 days with precipitation over a part of the Upper Thracian lowland in Bulgaria from May to September of 2002-2006 are studied in order to determine meteorological variables that may be used to specify the type of precipitation (rain or hail) on the ground. The cases have been divided into two samples — days with frontal convective clouds (125) and days with free convection (30). Analyses reveal that the mean values and the thresholds of CAPE and LI during the days with hail are similar to their corresponding values determined for thunderstorm development in other regions in Europe. Results show that none of the analyzed instability indices or environmental parameters alone is able to determine the type of precipitation on the ground. The best classification function of the cases according to the type of precipitation (rain or hail) is derived when the in-cloud characteristics simulated by 1-D numerical cloud model are included together with the instability indices and the environmental parameters as variables in the stepwise discriminant analysis. The analysis reveals that the simulated characteristics of the vertical velocity are an important ingredient in the classification function of the type of precipitation on the ground, due to the incorporation of the non-linear impact of environmental conditions on the formation of precipitation.

Dimitrova, Tsvetelina; Mitzeva, Rumjana; Savtchenko, Aglika

3

Mesoscale aspects of convective storms  

NASA Technical Reports Server (NTRS)

The structure, evolution and mechanisms of mesoscale convective disturbances are reviewed and observation techniques for "nowcasting" their nature are discussed. A generalized mesometeorological scale is given, classifying both low and high pressure systems. Mesoscale storms are shown often to induce strong winds, but their wind speeds are significantly less than those accompanied by submesoscale disturbances, such as tornadoes, downbursts, and microbursts. Mesoscale convective complexes, severe storm wakes, and flash floods are considered. The understanding of the evolution of supercells is essential for improving nowcasting capabilities and a very accurate combination of radar and satellite measurements is required.

Fujita, T. T.

1981-01-01

4

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. The module comes with audio narration, rich graphics, and a companion print version.

Comet

2003-11-18

5

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

6

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

7

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. Subject matter expects for A Convective Storm Matrix: Buoyancy/Shear Dependencies include Mr. Steve Keighton, Mr. Ed Szoke, and Dr. Morris Weisman. Note: This module was originally published on CD-ROM in March 1996 (v1.1) and re-released in 2001 as v1.3 for Microsoft Windows users only. CD-ROM version 1.3 works fairly well with Windows 98/ME/NT4/2000 but has reported to be problematic with Windows XP. Users of version 1.1 should obtain the patch located at http://www.comet.ucar.edu/help/ModuleSupport/matrix_problem.htm or use the new, Web-based module.

Comet

2003-04-09

8

Observations of Florida Convective Storms Using Dual Wavelength Airborne Radar  

NASA Technical Reports Server (NTRS)

NASA conducted the Cirrus Regional Study of Tropical Anvils and Cirrus Layers (CRYSTAL) Florida Area Cirrus Experiment (FACE) during July 2002 for improved understanding of tropical cirrus. One of the goals was to improve the understanding of cirrus generation by convective updrafts. The reasons why some convective storms produce extensive cirrus anvils is only partially related to convective instability and the vertical transport ice mass by updrafts. Convective microphysics must also have an important role on cirrus generation, for example, there are hypotheses that homogeneous nucleation in convective updrafts is a major source of anvil ice particles. In this paper, we report on one intense CRYSTAL- FACE convective case on 16 July 2002 that produced extensive anvil.

Heymsfield, G. M.; Heymsfield, A. J.; Belcher, L.

2004-01-01

9

Improved rainfall estimates in convective storms using polarisation diversity radar  

Microsoft Academic Search

Errors arise when using conventional radar reflectivity, Z, to estimate rainfall rate, R, and these can be particularly severe during severe convective storms; the very events when accurate estimates are needed so that action can be taken to mitigate the effects of flooding. Concentration is on three problems associated with heavy rainfall: hail, attenuation and absolute calibration of the radar,

A. J. Illingworth; T. M. Blackman; J. W. F. Goddard

2000-01-01

10

The Storm-Structure-Severity method for the identification of convective storm characteristics with conventional weather radar  

Microsoft Academic Search

Radar reflectivity information is often displayed in two dimensions, making it difficult to extract the structural characteristics of convective storms. The maximum radar reflectivity and the vertical profile of liquid water distribution in a vertical column of a convective cell is used to determine a structural and intensity classification of the cell. The application of this Storm-Structure-Severity classification is demonstrated

Petrus J. M. Visser

2001-01-01

11

Late-summer Martian Dust Storm  

NASA Technical Reports Server (NTRS)

This is an image of Mars taken from orbit by the Mars Reconnaissance Orbiter's Mars Color Imager (MARCI). The Red Planet's polar ice-cap is in the middle of the image. Captured in this image is a 37,000 square-kilometer (almost 23,000 miles) dust storm that moved counter-clockwise through the Phoenix landing site on Oct 11, 2008, or Sol 135 of the mission.

Viewing this image as if it were the face of a clock, Phoenix is shown as a small white dot, located at about 10 AM. The storm, which had already passed over the landing site earlier in the day, is located at about 9:30 AM.

2008-01-01

12

Relationships between Convective Storm Kinematics, Precipitation, and Lightning  

Microsoft Academic Search

Combined multiparameter radar, dual-Doppler, thermodynamic sounding, and lightning observations of 11 thunderstorms (6 from the midlatitudes, 5 from the Tropics) are examined. The thunderstorms span a wide spectrum of intensities, from weak monsoontype to severe tornadic, and include both unicellular and multicellular convection. In general, the kinematically strongest storms featured lower production of negative cloud-to-ground lightning (typically ,1 min21 flash

Timothy J. Lang; Steven A. Rutledge

2002-01-01

13

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

14

Observations of Florida Convective Storms using Dual Wavelength Airborne Radar  

NASA Technical Reports Server (NTRS)

NASA conducted the Cirrus Regional Study of Tropical Anvils and Cirrus Layers (CRYSTAL) Florida Area Cirrus Experiment (FACE) during July 2002 for improved understanding of tropical cirrus. One of the goals was to improve the understanding of cirrus generation by convective updrafts. The reasons why some convective storms produce extensive cirrus anvils is only partially related to convective instability and the vertical transport ice mass by updrafts. Convective microphysics must also have an important role on cirrus generation, for example, there are hypotheses that homogeneous nucleation in convective updrafts is a major source of anvil ice particles. In this paper, we report on one intense CRYSTAL-FACE convective case on 16 July 2002 that produced extensive anvil. During CRYSTAL-FACE, up to 5 aircraft flying from low- to high-altitudes, were coordinated for the study of thunderstorm-generated cirrus. The NASA high-altitude (20 km) ER-2 aircraft with remote sensing objectives flew above the convection, and other aircraft such as the WB-57 performing in situ measurements flew below the ER-2. The ER-2 remote sensing instruments included two nadir viewing airborne radars. The CRS 94 GHz radar and the EDOP 9.6 GHz radar were flown together for the first time during CRYSTAL-FACE and they provided a unique opportunity to examine the structure of 16 July case from a dual-wavelength perspective. EDOP and CRS are complementary for studying convection and cirrus since CRS is more sensitive than EDOP for cirrus, and EDOP is considerably less attenuating in convective regions. In addition to the aircraft, coordinated ground-based radar measurements were taken with the NPOL S-Band (3 GHz) multiparameter radar. One of the initial goals was to determine whether dual-wavelength airborne measurements could identify supercooled water regions.

Heymsfield, G. M.; Heymsfield, A. J.; Belcher, L.

2004-01-01

15

Particle Energization During Magnetic Storms with Steady Magnetospheric Convection  

NASA Astrophysics Data System (ADS)

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

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

2013-12-01

16

Empirical reconstruction of storm-time steady magnetospheric convection events  

NASA Astrophysics Data System (ADS)

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

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

2013-12-01

17

Formaldehyde Photochemistry in the Upper Troposphere in and Near Convective Storms During the DC3 Study  

NASA Astrophysics Data System (ADS)

The 2012 Deep Convective Clouds and Chemistry (DC3) campaign in the summer of 2012 provided an opportunity to study the impacts of deep convection on various reactive and soluble precursors of ozone and HOx radicals in the upper troposphere and lower stratosphere over North America. Formaldehyde (CH2O) is one such gas. Formaldehyde measurements on the NASA DC-8 aircraft by difference frequency generation infrared absorption spectroscopy (DFGAS) and laser-induced fluorescence along with DFGAS measurements on the NSF/NCAR GV aircraft were acquired in the inflow and outflow of numerous storms over the course of this study. An overview of these measurements with past measurements over the continental U.S. will be given for both context and to illustrate the magnitude of CH2O perturbations caused by deep continental convection. A number of case studies were identified for comparison of these measurements with the NASA Langley Lagrangian photochemical box model and the WRF-Chem model. The former is constrained by time varying observations of CH2O precursors in both the boundary layer and upper troposphere to determine the magnitude of CH2O produced by gas-phase photochemistry in both the storm core and the outflow at various times for different storm types. These determinations will be used as a constraint on CH2O scavenging efficiency results obtained by a 3-component mixture method and as a means to assess the magnitude of potential CH2O production mechanisms from other sources such as heterogeneous production when smoke plumes intercept clouds.

Fried, A.; Weibring, P.; Richter, D.; Walega, J.; Olson, J. R.; Crawford, J. H.; Diskin, G. S.; Sachse, G. W.; Hanisco, T. F.; Arkinson, H. L.; Barth, M. C.; Campos, T. L.; Flocke, F. M.; Apel, E. C.; Hornbrook, R. S.; Hall, S. R.; Bela, M. M.; Cantrell, C. A.; Blake, D. R.; Blake, N. J.

2013-12-01

18

The Storm-Structure-Severity method for the identification of convective storm characteristics with conventional weather radar  

NASA Astrophysics Data System (ADS)

Radar reflectivity information is often displayed in two dimensions, making it difficult to extract the structural characteristics of convective storms. The maximum radar reflectivity and the vertical profile of liquid water distribution in a vertical column of a convective cell is used to determine a structural and intensity classification of the cell. The application of this Storm-Structure-Severity classification is demonstrated by investigating a tornado event on 15 November 1998 in Harrismith, South Africa, by using volume-scanned reflectivity data from the S-band MRL-5 radar. The regions of convective development, decay and mesocyclone evolution are identified with this classification. The method is able to extract the three-dimensional structural information of convective storms embedded in volume-scanned reflectivity data and present it in a simple display format.

Visser, Petrus J. M.

2001-03-01

19

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

20

Thunderstorms In some storms, convection produces lightning and thunder. Although storm electrification can occur in a variety of circumstances, most thunderstorms  

E-print Network

1 Thunderstorms In some storms, convection produces lightning and thunder. Although storm electrification can occur in a variety of circumstances, most thunderstorms develop under atmospheric conditions corresponds to the rising air, or updraft, within the thunderstorm. Cloud material accumulates

Doswell III, Charles A.

21

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

2013-09-01

22

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

23

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

E-print Network

Midweek increase in U.S. summer rain and storm heights suggests air pollution invigorates with detectable rain. TRMM radar data show a significant midweek increase in the echo-top heights reached.-M. Yoo, M.-I. Lee, and M. Hahnenberger (2008), Midweek increase in U.S. summer rain and storm heights

Daniel, Rosenfeld

24

Atmospheric infrasound observed during intense convective storms on 9-10 July 2011  

NASA Astrophysics Data System (ADS)

Atmospheric infrasound of frequencies 0.1-4 Hz observed in Central Europe during convective storms on 9-10 July 2011 from 21:00 to 02:57 UT was analysed. Azimuth of signal arrival followed positions of the convective storms passing over the region of measurements from south-west to north-east. Significant variations in azimuths of signal arrival (up to 105°) occurred periodically between 21:30 and 23:00 UT, at the time of maximum development of convective storms. Sprites (discharges in the mesosphere) seem to be potential sources of these infrasound signals. Stable infrasound arrivals were observed between 02:00 and 02:57 UT from direction where abating convective storms were located.

Sindelarova, T.; Chum, J.; Skripnikova, K.; Base, J.

2015-01-01

25

The role of near surface outflow in maintaining convective activity. [in storms  

NASA Technical Reports Server (NTRS)

Continuous measurements of horizontal velocity, temperature and humidity at the surface over a dense network of stations were used to examine the behavior, at the surface, of a large number of convective storms. Feedback between storm outflow at the surface and the generation of convective cells is demonstrated. The outflow is shown in the surface divergence fields once rain begins, with characteristics common to storms in distinctly different meteorological environments, such as summertime Florida and Illinois. This commencement precedes the occurence of rainfall and radar echo in the location of the cell by some tens of minutes up to more than 100 mins. Given surface measurements with a spacing of no more than 10 km, the direction of propagation, timing of the future occurence of rainfall and the intensity of the rainfall generated in the cell can be determined.

Garstang, M.; Cooper, H. J.

1981-01-01

26

Sensitivity of Severe Convective Storms to Soil Moisture and Lower Atmospheric Water Vapor  

NASA Astrophysics Data System (ADS)

Numerous studies have examined the sensitivity of the atmospheric state to soil moisture on time scales of up to a day. Dry line intensity, lower tropospheric water vapor content, and precipitation have all been shown through modeling studies to be affected by modest perturbations to upstream soil moisture content and subsequent lower atmospheric water vapor. Since all of these aspects could be associated with convection, a high-impact forecast event that exhibits rapid nonlinear error growth, it is reasonable to expect that irrigation practices might influence severe convective storms. Understanding the link between soil moisture and specific convective elements could have broad implications for severe weather forecasting, and could reveal the degree to which irrigation-induced storm-scale inadvertent weather modification exists. This work examines the sensitivity to soil moisture and lower atmospheric water vapor content of a severe convective storm that struck Moore, Oklahoma, USA on May 20th, 2013, killing 24 people. While adjoint sensitivity analysis that employs the tangent linear version of a numerical weather prediction model might be used to examine convective sensitivities to soil moisture, the strong nonlinearity associated with these events likely renders this technique inaccurate. Alternatively, the approach here utilizes backward trajectory analysis to identify the regions up to a day prior to which the storm might be sensitive. Once the regions are identified, an ensemble of model forecasts is created by varying initial soil moisture to reveal the degree to which perturbations must be made to influence the downstream storm. Subsequent comparisons are made between the required soil moisture perturbations and realistic soil water values added through irrigation.

Ancell, Brian; Nauert, Christian

2014-05-01

27

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

NASA Technical Reports Server (NTRS)

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

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

1986-01-01

28

Observations of lightning in convective supercells within tropical storms and hurricanes  

SciTech Connect

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

Lyons, W.A.; Keen, C.S. [Mission Research Corp., Fort Collins, CO (United States)] [Mission Research Corp., Fort Collins, CO (United States); [Mankato State Univ., Mankato, MN (United States)

1994-08-01

29

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

NASA Astrophysics Data System (ADS)

Saturn's Great Storm of 2010-2011 was first detected by amateur astronomers in early December 2010 and later found in Cassini Imaging Science Subsystem (ISS) images taken on 5 December, when it took the form of a 1000 km wide bright spot. Within a week the head of the storm grew by a factor of ten in width and within a few months created a wake that encircled the planet. This is the sixth Great Saturn Storm in recorded history, all having appeared in the northern hemisphere, and most near northern summer solstice at intervals of roughly 30 years (Sanchez-Lavega et al. 1991, Nature 353, 397-401). That the most recent storm appeared 10 years early proved fortunate because Cassini was still operating in orbit around Saturn and was able to provide unique observations from which we could learn much more about these rare and enormous events. Besides the dramatic dynamical effects displayed at the visible cloud level by high-resolution imaging observations (Sayanagi et al. 2013, Icarus 223, 460-478), dramatic thermal changes also occurred in the stratosphere above the storm (Fletcher et al. 2011, Science 332, 1413), and radio measurements of lightning (Fischer et al., 2011, Nature 475, 75-77) indicated strong convective activity at deeper levels. Numerical models of Saturn's Giant storms (Hueso and Sanchez-Lavega 2004, Icarus 172, 255-271) suggest that they are fueled by water vapor condensation beginning at the 10-12 bar level, some 250 km below the visible cloud tops. That idea is also supported by our detection of water ice near the cloud tops (Sromovsky et al. 2013, Icarus 226, 402-418). From Cassini VIMS spectral imaging taken in February 2011, we learned that the storm's cloud particles are strong absorbers of sunlight at wavelengths from 2.8 to 3.1 microns. Such absorption is not seen on Saturn outside of storm regions, implying a different kind of cloud formation process as well as different cloud composition inside the storm region. We found compelling evidence that the storm cloud contains a multi-component aerosol population. We needed at least three different materials to obtain good spectral fits. The most obvious contributor is ammonia ice, with water ice the best-defined secondary component. The most likely third component is ammonium hydrosulfide or some weakly absorbing material similar to what dominates visible clouds outside the storm region. Horizontally heterogeneous cloud models favor ammonium hydrosulfide as the third component, while horizontally uniform models favor the weak absorber. Both models rely on water ice absorption to compensate for residual spectral gradients produced by ammonia ice from 3.0 microns to 3.1 microns and need the relatively conservative third component to fill in the sharp ammonia ice absorption peak near 2.96 microns. The best heterogeneous model has spatial coverage fractions of 55% ammonia ice, 22% water ice, and 23% ammonium hydrosulfide. The best homogeneous model has an optically thin layer of weakly absorbing particles above an optically thick layer of water ice particles coated by ammonia ice. These Cassini data provide the first spectroscopic evidence of water ice in Saturn's atmosphere. This research was supported by NASA's Outer Planets Research Program under grant NNX11AM58G.

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

2013-12-01

30

Sensitivity of the Amazon rainforest to convective storms  

NASA Astrophysics Data System (ADS)

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

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

2012-12-01

31

GOES 12 observations of convective storm variability and evolution during the Tropical Composition, Clouds and Climate Coupling Experiment field program  

NASA Astrophysics Data System (ADS)

This study characterizes convective clouds that occurred during the Tropical Composition, Clouds and Climate Coupling Experiment as observed within GOES imagery. Overshooting deep convective cloud tops (OT) that penetrate through the tropical tropopause layer and into the stratosphere are of particular interest in this study. The results show that there were clear differences in the areal coverage of anvil cloud, deep convection, and OT activity over land and water and also throughout the diurnal cycle. The offshore waters of Panama, northwest Colombia, and El Salvador were the most active regions for OT-producing convection. A cloud object tracking system is used to monitor the duration and areal coverage of convective cloud complexes as well as the time evolution of their cloud-top microphysical properties. The mean lifetime for these complexes is 5 hours, with some existing for longer than 16 hours. Deep convection is found within the anvil cloud during 60% of the storm lifetime and covered 24% of the anvil cloud. The cloud-top height and optical depth at the storm core followed a reasonable pattern, with maximum values occurring 20% into the storm lifetime. The values in the surrounding anvil cloud peaked at a relative age of 20%-50% before decreasing as the convective cloud complex decayed. Ice particle diameter decreased with distance from the core but generally increased with storm age. These results, which characterize the average convective system during the experiment, should be valuable for formulating and validating convective cloud process models.

Bedka, Kristopher M.; Minnis, Patrick

2010-05-01

32

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

NASA Technical Reports Server (NTRS)

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

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

1991-01-01

33

HEAT TRANSFERS IN A DOUBLE SKIN ROOF VENTILATED BY NATURAL CONVECTION IN SUMMER TIME  

E-print Network

or in tropical and arid countries. In this work, radiation, convection and conduction heat transfers and the sheet metal: This is ventilation by natural convection. The remaining conductive heat from the sheet1 HEAT TRANSFERS IN A DOUBLE SKIN ROOF VENTILATED BY NATURAL CONVECTION IN SUMMER TIME P. H

Boyer, Edmond

34

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

35

The importance of storm time steady magnetospheric convection in determining the final relativistic electron flux level  

NASA Astrophysics Data System (ADS)

electrons pose a space weather hazard to satellites in the radiation belts. Although about half of all geomagnetic storms result in relativistic electron flux enhancements, other storms decrease relativistic electron flux, even under similar solar wind drivers. Radiation belt fluxes depend on a complex balance between transport, loss, and acceleration. A critically important aspect of radiation belt enhancements is the role of the "seed" population—plasma sheet particles heated and transported earthward by magnetotail processes—which can become accelerated by wave-particle interactions with chorus waves. While the effect of substorms on seed electron injections has received considerable focus, in this study we present a previously unexplored connection between quasi-steady convection during steady magnetospheric convection (SMC) events and the transport and energization of electrons. SMC events are long-duration intervals of enhanced convection without any substorm expansions and are an important mechanism in coupling magnetotail plasma populations to the inner magnetosphere. We find that storms with SMCs in the recovery phase are more likely to increase relativistic electron flux levels, while storms without SMCs are more likely to result in a decrease. Using particle measurements from the Time History of Events and Macroscale Interactions During Substorms mission, we show that phase space density of seed electron populations increases 1 h before SMC start and stays elevated through the duration of SMCs. Chorus activity is also elevated during SMC events. These results suggest that rather than hindering electron acceleration by diverting plasma away from the inner magnetosphere, SMC events appear to act to enhance and maintain seed electron populations.

Kissinger, Jennifer; Kepko, Larry; Baker, Daniel N.; Kanekal, Shri; Li, Wen; McPherron, Robert L.; Angelopoulos, Vassilis

2014-09-01

36

Improving storm-scale analyses of convection via assimilation of polarimetric radar observations  

NASA Astrophysics Data System (ADS)

Quantitative precipitation forecasting is one of the greatest challenges currently facing the operational meteorological community. Modern short-term numerical forecasts only provide limited guidance owing to their coarse spatial and temporal resolution in comparison to the smaller scales needed to capture individual storms and their use of bulk-microphysical schemes. Further, convective events are often poorly resolved by the operational observing network, leading to poor analyses of the initial atmospheric state and subsequently poor forecasts. Presently, the Doppler radar network offers the only volumetric data suitable for more accurate assimilation on the storm scale. With polarimetric upgrades to the operational Doppler network underway, assimilating polarimetric radar observations will allow further improvement in the estimating the current atmospheric state. Further, more accurate retrieval of unobserved fields in real time, such as the low-level cold pool beneath supercell storms, would aid forecasters in current and future hazard assessment. An existing ensemble Kalman filter data assimilation system developed at NSSL was upgraded to enable assimilation of real polarimetric radar observations through integration of an advanced dual-moment microphysical scheme and through development of forward operators for the polarimetric radar observables. The resulting differential reflectivity and specific differential phase operators have been shown to produce realistic polarimetric radar signatures for an observed supercell storm event. In addition, the system provided good retrieval of storm kinematic features that were enhanced through use of advanced microphysics and assimilation of polarimetric radar observations. A detailed examination of the case study led to new insight into polarimetric field evolution associated with a significantly tornadic supercell thunderstorm. This included the identification of a specific differential phase foot and differential reflectivity shield as well as the first documentation focused on the relationship between polarimetric field evolution relative to surface gust front behavior. A strong but compact cold pool was found on the upshear side of the storm. However, an intriguing discovery was the lack of significant cooling at the surface within the forward flank downdraft region of the storm. Instead, there was an elevated cold pool along the forward storm flank that rested on a capping inversion layer. Comparison of the retrieved atmospheric state variables between the simple and advanced microphysical representation showed significant differences in spatial and temporal evolution, yet retrieved cold pool characteristics were qualitatively quite similar to one another and observations. This is related to the similar treatment of evaporation between the two microphysical schemes along the upshear side of the storm.

Romine, Glen Scott

37

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

38

Aerosol impacts on deep convective storms in the tropics: A combination of modeling and observations  

NASA Astrophysics Data System (ADS)

It is widely accepted that increasing the number of aerosols available to act as cloud condensation nuclei (CCN) will have significant effects on cloud properties, both microphysical and dynamical. This work focuses on the impacts of aerosols on deep convective clouds (DCCs), which experience more complicated responses than warm clouds due to their strong dynamical forcing and the presence of ice processes. Several previous studies have seen that DCCs may be invigorated by increasing aerosols, though this is not the case in all scenarios. The precipitation response to increased aerosol concentrations is also mixed. Often precipitation is thought to decrease due to a less efficient warm rain process in polluted clouds, yet convective invigoration would lead to an overall increase in surface precipitation. In this work, modeling and observations are both used in order to enhance our understanding regarding the effects of aerosols on DCCs. Specifically, the area investigated is the tropical East Atlantic, where dust from the coast of Africa frequently is available to interact with convective storms over the ocean. The first study investigates the effects of aerosols on tropical DCCs through the use of numerical modeling. A series of large-scale, two-dimensional cloud-resolving model simulations was completed, differing only in the concentration of aerosols available to act as CCN. Polluted simulations contained more deep convective clouds, wider storms, higher cloud tops and more convective precipitation across the entire domain. Differences in the warm cloud microphysical processes were largely consistent with aerosol indirect theory, and the average precipitation produced in each DCC column decreased with increasing aerosol concentration. A detailed microphysical budget analysis showed that the reduction in collision and coalescence largely dominated the trend in surface precipitation; however the production of rain through the melting of ice, though it also decreased, became more important as the aerosol concentration increased. The DCCs in polluted simulations contained more frequent, stronger updrafts and downdrafts, but the average updraft speed decreased with increasing aerosols in DCCs above 6 km. An examination of the buoyancy term of the vertical velocity equation demonstrates that the drag associated with condensate loading is an important factor in determining the average updraft strength. The largest contributions to latent heating in DCCs were cloud nucleation and vapor deposition onto water and ice, but changes in latent heating were, on average, an order of magnitude smaller than those in the condensate loading term. It is suggested that the average updraft is largely influenced by condensate loading in the more extensive stratiform regions of the polluted storms, while invigoration in the convective core leads to stronger updrafts and higher cloud tops. The goal of the second study was to examine observational data for evidence that would support the findings of the modeling work. In order to do this, four years of CloudSat data were analyzed over a region of the East Atlantic, chosen for the similarity (in meteorology and the presence of aerosols) to the modeling study. The satellite data were combined with information about aerosols taken from the output of a global transport model, and only those profiles fitting the definition of deep convective clouds were analyzed. Overall, the cloud center of gravity, cloud top, rain top, and ice water path were all found to increase with increased aerosol loading. These findings are in agreement with what was found in the modeling work, and are suggestive of convective invigoration with increased aerosols. In order to separate environmental effects from that due to aerosols, the data were sorted by environmental convective available potential energy (CAPE) and lower tropospheric static stability (LTSS). The aerosol effects were found to be largely independent of the environment. A simple statistical test suggests that the difference between the cleanest and most pol

Storer, Rachel Lynn

39

Convective Activities in the Tropical Western Pacific and Their Impact on the Northern Hemisphere Summer Circulation  

Microsoft Academic Search

Interannual and intraseasonal variations of convective activities in the tropical western Pacific during summer and their impact on the Northern Hemisphere circulation are investigated by using satellite cloud amount, sea surface temperature (SST) and geopotential data for 7 years (1978-1984). During summers when SST in the tropical western Pacific is about 1.0°C warmer than normal, active convection regions consisting of

Tsuyoshi Nitta

1987-01-01

40

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

NASA Technical Reports Server (NTRS)

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

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

2007-01-01

41

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

NASA Technical Reports Server (NTRS)

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

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

1982-01-01

42

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

43

Sprite-producing Convective Storms within the Colorado Lightning Mapping Array  

NASA Astrophysics Data System (ADS)

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

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

2012-12-01

44

A Single Doppler Radar Study of Horizontal-Roll Convection in a Lake-Effect Snow Storm.  

NASA Astrophysics Data System (ADS)

The boundary-layer structure and circulation over Lake Michigan were probed with a Doppler radar and an aircraft during a lake-effect snow storm on 9 December 1978. Evidence is presented that observed wind-parallel echo bands and satellite cloud bands resulted from horizontal-roll convection in the boundary layer. The organization of precipitation within the roll field is discussed, and the roll geometry is compared with cases of dry horizontal-roll convection reported in the literature.

Kelly, Robert D.

1982-07-01

45

Assessment of the European Severe Convective Storm Climatology using Reanalysis Data  

NASA Astrophysics Data System (ADS)

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

Pistotnik, Georg; Groenemeijer, Pieter; Kühne, Thilo

2013-04-01

46

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

NASA Technical Reports Server (NTRS)

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

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

2014-01-01

47

Doppler radar observations of the evolution of a small convective storm during Cohmex. [Cooperative Huntsville Meteorological Experiment  

NASA Technical Reports Server (NTRS)

Doppler radar observations of a deep convection that developed along the Alabama-Tennesse border on July 14, 1986 are analyzed. The evolution and structure of the convective storm are examined. Two convective cores are observed and both having a radius of about 1 km and maximum reflectivities of about 5 dBz; a third cell is also detected later in the region between the northern and southern cells. It is noted that the northern cell is the most dominant possessing an updraft through the region of maximum reflectivity. Diagrams of the vertical structure of the cells are provided.

Moore, Patrick D.; Ray, Peter S.

1989-01-01

48

Severe convection and lightning in subtropical South America  

NASA Astrophysics Data System (ADS)

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

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

2014-10-01

49

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

NASA Technical Reports Server (NTRS)

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

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

1980-01-01

50

Can stable isotopes ride out the storms? The role of convection for water isotopes in models, records, and paleoaltimetry studies in the central Andes  

NASA Astrophysics Data System (ADS)

Globally, changes in stable isotope ratios of oxygen and hydrogen (? 18O and ? D ) in the meteoric water cycle result from distillation and evaporation processes. Isotope fractionation occurs when air masses rise in elevation, cool, and reduce their water-vapor holding capacity with decreasing temperature. As such, ? 18O and ? D values from a variety of sedimentary archives are often used to reconstruct changes in continental paleohydrology as well as paleoaltimetry of mountain ranges. Based on 234 stream-water samples, we demonstrate that areas experiencing deep convective storms in the eastern south-central Andes (22-28° S) do not show the commonly observed relationship between ? 18O and ? D with elevation. These convective storms arise from intermontane basins, where diurnal heating forces warm air masses upward, resulting in cloudbursts and raindrop evaporation. Especially at the boundary between the tropical and extra-tropical atmospheric circulation regimes where deep-convective storms are very common (?26° to 32° N and S), the impact of such storms may yield non-systematic stable isotope-elevation relationships as convection dominates over adiabatic lifting of air masses. Because convective storms can reduce or mask the depletion of heavy isotopes in precipitation as a function of elevation, linking modern or past topography to patterns of stable isotope proxy records can be compromised in mountainous regions, and atmospheric circulation models attempting to predict stable isotope patterns must have sufficiently high spatial resolution to capture the fractionation dynamics of convective cells.

Rohrmann, Alexander; Strecker, Manfred R.; Bookhagen, Bodo; Mulch, Andreas; Sachse, Dirk; Pingel, Heiko; Alonso, Ricardo N.; Schildgen, Taylor F.; Montero, Carolina

2014-12-01

51

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

NASA Technical Reports Server (NTRS)

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

Wilson, G. S.

1977-01-01

52

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

PubMed

The observed presence of water vapor convectively injected deep into the stratosphere over the United States can fundamentally change the catalytic chlorine/bromine free-radical chemistry of the lower stratosphere by shifting total available inorganic chlorine into the catalytically active free-radical form, ClO. This chemical shift markedly affects total ozone loss rates and makes the catalytic system extraordinarily sensitive to convective injection into the mid-latitude lower stratosphere in summer. Were the intensity and frequency of convective injection to increase as a result of climate forcing by the continued addition of CO(2) and CH(4) to the atmosphere, increased risk of ozone loss and associated increases in ultraviolet dosage would follow. PMID:22837384

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

2012-08-17

53

Convective Storm Nowcasting Applications of McIDAS-V Kristopher Bedka3  

E-print Network

Speed (kt) COMET, 1999: Mesoscale Convective Systems: Squall Lines and Bow Echoes. Online training editor can be applied to generate convective cloud mask images for pattern recognition. Transects (cross

Kuligowski, Bob

54

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

55

The analysis and impact of simulated high-resolution surface observations in addition to radar data for convective storms with an ensemble Kalman filter  

Microsoft Academic Search

Observing system simulation experiments are performed using an ensemble Kalman filter to investigate the impact of surface\\u000a observations in addition to radar data on convective storm analysis and forecasting. A multi-scale procedure is used in which\\u000a different covariance localization radii are used for radar and surface observations. When the radar is far enough away from\\u000a the main storm so that

Jili DongMing; Ming Xue; Kelvin Droegemeier

2011-01-01

56

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

NASA Technical Reports Server (NTRS)

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

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

2001-01-01

57

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

NASA Technical Reports Server (NTRS)

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

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

2001-01-01

58

Heat transfers in a double-skin roof ventilated by natural convection in summer time  

E-print Network

The double-skin roofs investigated in this paper are formed by adding a metallic screen on an existing sheet metal roof. The system enhances passive cooling of dwellings and can help diminishing power costs for air conditioning in summer or in tropical and arid countries. In this work, radiation, convection and conduction heat transfers are investigated. Depending on its surface properties, the screen reflects a large amount of oncoming solar radiation. Natural convection in the channel underneath drives off the residual heat. The bi-dimensional numerical simulation of the heat transfers through the double skin reveals the most important parameters for the system's efficiency. They are, by order of importance, the sheet metal surface emissivity, the screen internal and external surface emissivity, the insulation thickness and the inclination angle for a channel width over 6 cm. The influence of those parameters on Rayleigh and Nusselt numbers is also investigated. Temperature and air velocity profiles on seve...

Biwole, Pascal; Pompeo, C

2013-01-01

59

Observations on thermospheric and mesospheric density disturbances caused by typhoons and convective storms  

NASA Technical Reports Server (NTRS)

Atmospheric parameter observations have been conducted during the passage of typhoons and tropical storms, from the troposphere to the middle atmosphere, and thence to the thermosphere, using the VHF radar and HF Doppler sounder at an observation site in Taiwan. The density perturbations caused by the propagation of gravity waves due to the typhoons and tropical storms were calculated on the basis of these observations. The short-term middle atmospheric and thermospheric density changes are significant factors in spacecraft launches. The successful remote measurement of three-dimensional winds, gravity waves, and density perturbations is demonstrated for this subtropical site.

Hung, R. J.; Tsao, Y. D.; Lee, C. C.; Johnson, D. L.; Chen, A. J.

1990-01-01

60

Origin of the pre-tropical storm Debby (2006) African easterly wave-mesoscale convective system  

NASA Astrophysics Data System (ADS)

The origins of the pre-Debby (2006) mesoscale convective system (MCS) and African easterly wave (AEW) and their precursors were traced back to the southwest Arabian Peninsula, Asir Mountains (AS), and Ethiopian Highlands (EH) in the vicinity of the ITCZ using satellite imagery, GFS analysis data and ARW model. The sources of the convective cloud clusters and vorticity perturbations were attributed to the cyclonic convergence of northeasterly Shamal wind and the Somali jet, especially when the Mediterranean High shifted toward east and the Indian Ocean high strengthened and its associated Somali jet penetrated farther to the north. The cyclonic vorticity perturbations were strengthened by the vorticity stretching associated with convective cloud clusters in the genesis region—southwest Arabian Peninsula. A conceptual model was proposed to explain the genesis of convective cloud clusters and cyclonic vorticity perturbations preceding the pre-Debby (2006) AEW-MCS system.

Lin, Yuh-Lang; Liu, Liping; Tang, Guoqing; Spinks, James; Jones, Wilson

2013-05-01

61

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

62

Mesospheric concentric gravity waves generated by multiple convective storms over the North American Great Plain  

NASA Astrophysics Data System (ADS)

We report on six continuous hours of OH airglow imager observations (at z ˜ 87 km) of convectively generated gravity waves (GWs) near Fort Collins, Colorado, on the evening of 08 September 2005. These GWs appeared as nearly concentric rings, and had epicenters near the locations of deep convection in three thunderstorms in Colorado, Nebraska and South Dakota. Using GOES satellite and weather radar observations, we show that the GWs closely follow the thunderstorms. Using the background wind from a nearby radar, the intrinsic wave parameters and vertical wavelengths are calculated. The temperature perturbations are estimated to be T?/T¯ ˜ 1-3% for GWs with horizontal wavelengths ?h ˜ 20-40 km and horizontal phase speeds ˜40-60 m/s. The horizontal wavelengths of GWs from a convective cluster decreased in time from 30 to 15 km. We employ convective plume and ray-trace models to simulate the GW-induced OH intensity perturbations from convective plumes, clusters and complexes. We find that the results using the background model wind (radiosonde/TIME-GCM) agree well with the late-time observations, when the images are dominated by southwestward, short-wavelength, high-frequency GWs. These late-time GWs propagate against the background wind, and have ?h ˜ 30-40 km and periods of ? ˜ 20-30 min. The OH intensity perturbations are enhanced because the vertical wavelengths ?z increased, T?/T¯ increased, and the vertical velocity perturbations w? decreased (because the GWs were near their reflection levels). We also find that these short-wavelength GWs were created ˜5 h earlier by an extremely energetic, deep convective plume in South Dakota, thereby showing that small-scale, convective GWs directly link the troposphere and mesopause region.

Vadas, Sharon; Yue, Jia; Nakamura, Takuji

2012-04-01

63

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

64

A case study of aerosol impacts on summer convective clouds and precipitation over northern China  

NASA Astrophysics Data System (ADS)

The emissions such as greenhouse gases, precursor gases and particulate matters may directly alter the Earth radiative budget or indirectly modify cloud and precipitation processes, and possibly induce changes in climate and the hydrological cycle at the regional to global scale. The previous publications reported a few quantitative assessments and inconsistent results on the effects of the emissions on cloud and precipitation. The aerosol properties and possible impacts on a convective precipitation case on 4 July 2008 over the urban region of northern China are investigated based on the Moderate Resolution Imaging Spectroradiometer (MODIS) data and the Weather Research and Forecast (WRF) model coupled with Chemistry (WRF-Chem). Results show that the Aerosol Optical Depth (AOD) is over 0.9 in the study area, indicating a high concentration of aerosol pollution. The value of Angstrom exponent in the study area is larger than 1.0, indicating that the main particles in the area are industrial and biomass burning pollution aerosols with radii less than 0.25-0.5 ?m. The modeling results show that the domain-averaged precipitation amount under polluted conditions can be increased up to 17% during the whole cloud lifetime. However, the maximum rainfall rate above 30 mm/h is enhanced, whereas that below 30 mm/h is suppressed in most cloud lifetime. The differences of cloud microphysics and dynamics between polluted and clean conditions indicate that both warm and ice microphysics and updraft are suppressed at the storm's initial and dissipating stages, whereas those at the storm's mature stage are obviously enhanced under polluted conditions.

Guo, Xueliang; Fu, Danhong; Guo, Xin; Zhang, Chunming

2014-06-01

65

Urban Effects on Summer Monsoon Convection in Phoenix, Arizona (USA): A Model Case Study of Aug. 2-3, 2005  

E-print Network

Urban Effects on Summer Monsoon Convection in Phoenix, Arizona (USA): A Model Case Study of Aug. 2.clarke@asu.edu #12;2 Abstract The Weather Research and Forecasting Model (WRF) was used to simulate a typical North sensitivity analysis, the impact of urban physical characteristics that may affect thunderstorm development

Castro, Christopher L.

66

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

NASA Astrophysics Data System (ADS)

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

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

67

On the relationship between soil, vegetation and severe convective storms: Hungarian case studies  

NASA Astrophysics Data System (ADS)

The effects of soil hydraulic parameter and stomatal functioning parameterization changes upon the precipitation fields of storms were compared and analyzed. The analysis was performed using results from the Penn State-NCAR MM5 Modeling System. Two sets of soil hydraulic parameters, from the USA and Hungary, were used. Stomatal functioning is parameterized as simply as possible using Jarvis' approach. The days chosen for analysis (18th April 2005 and 7th August 2006) seemed to be favourable for local storms to form when the land-surface/air interaction is the strongest. Both days were wet, however, the prevailing moisture was somewhat larger on 18th April 2005. Precipitation fields were statistically analyzed in details. First, the simulated and observed fields were compared. The observed fields were estimated from rain-gauge data applying the ordinary block kriging interpolation technique. The agreement between the simulated and observed fields was estimated using categorical and continuous verification indices. Significance tests were done to estimate how large the obtained differences were. The results obtained indicate that precipitation fields are at least as sensitive to changes in soil hydraulic parameters as to changes in stomatal functioning parameterization. The simple Student t-test hypothesis was applied to estimate how large the precipitation differences obtained were. According to the estimates, the TSS differences obtained by soil parameter and stomatal functioning parameterization changes are significant on the 10% level. The acquired differences do not depend on the initialization of soil moisture. The results suggest that all weather and climate models used for regional purposes should prefer local soil data instead of some common globally used soil datasets. This is at least as important as the parameterization of stomatal functioning.

Horváth, Á.; Ács, F.; Breuer, H.

68

Severe Storms  

NSDL National Science Digital Library

Part of the University of Illinois Weather World 2010 project, this guide uses multimedia technology and the dynamic capabilities of the web to incorporate text, colorful diagrams, animations, computer simulations, audio, and video to introduce topics and concepts in the atmospheric sciences. This module is a combination of two elements. The first is the National Oceanic and Atmospheric Administration (NOAA) Severe Storms Spotters Guide. The second is a section discussing the efforts and results of modeling severe storms. The Spotters Guide contains supplemental instructional resources and a program designed to familiarize meteorologists and advanced severe storm spotters with the building blocks of convective storm structure. The focus of the training series is the development of a thunderstorm spectrum and a discussion of the physical characteristics and severe weather potential of the various storm types in the spectrum.

2010-01-01

69

Retrieval of Thermal and Microphysical Variables in Observed Convective Storms. Part 1: Model Development and Preliminary Testing.  

NASA Astrophysics Data System (ADS)

The air flow in convective storms, the force that regulate the flow, and the processes that produce hydrometeors of various kinds are all being studied intensively by meteorologists using Doppler radar observations. The research reported here proceeds from the observed motion through accompanying thermodynamic and micro-physical processes to the analysis of hydrometer content and thermal fields in thunderstorms. A three-dimensional numerical kinematic cloud model employing Doppler wind fields is developed and used to diagnose temperature and mixing ratios within a thunderstorm. The microphysical parameterization includes stochastic coalescence effects in warm clouds as well as well- and variable-density dry hail growth.Known fields from a dynamically simulated cloud are used to establish the accuracy of the retrieval scheme. Real data tests indicate good agreement between retrieved and observed radar reflectivities, qualitative dynamic consistency between observed winds and retrieved buoyancies, and the model's ability to partition liquid and solid hydrometeors. A modification of weighting factors in the variational multiple Doppler analysis changes the vertical motion field and improves the verification of retrieved reflectivities. This analysis sensitivity emphasizes the great influence of the input wind field on retrieved thunderstorm variables.

Ziegler, Conrad L.

1985-07-01

70

Determination of Storm Flashing/Non-Flashing Condition From Convective and Environmental Observations  

NASA Technical Reports Server (NTRS)

A simple and fundamental problem in cloud electrification is whether or not a cloud can be determined to be producing lightning or not producing lightning, based solely on knowledge of its microphysical (and perhaps environmental) state. A merged database of TRMM radar, microwave and lightning observations and NCEP reanalysis environmental parameters is used to answer this question, for the tropics. The formal skill of traditional, univariate rule-based approaches (e.g., 35 dBZ occurrence at 6 km altitude) is quantified (via the probability of detection (POD), false alarm rate (FAR) and critical skill index (CSI)). Under indiscriminate application to the tropics, peak rule-based CSI for categorization of flashing storms is approximately 50%, with peak POD approximately 67% and minimum FAR approximately 33%, with peak CSI found for radar reflectivity-based parameters at 7-7.5 km altitude (near -15C). Separation of land and ocean domains yields approximately 5-10% gains in CSI over land. Conventional multivariate categorization techniques (discriminant analysis) are then applied, and less conventional (neural network) categorization techniques are also discussed.

Boccippio, Dennis J.

2002-01-01

71

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

NASA Astrophysics Data System (ADS)

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

Redelsperger, J. L.; Sommeria, G.

1986-11-01

72

Skywarn Spotter Convective Basics  

NSDL National Science Digital Library

The "SKYWARN® Spotter Convective Basics" module will guide users to a basic understanding of convective storms. Through three different scenarios, you will cover reporting and proper communication of local storm reports to the National Weather Service (NWS), personal safety during these events, and field identification of convective storm hazards. After completing the scenarios, you will be given the opportunity to practice identifying storm features from a spectrum of photos.

Comet

2011-04-22

73

Unforced variability in summer storm track position over the past millennium  

NASA Astrophysics Data System (ADS)

Gridded past millennium climate reconstructions, encompassing the European continent (e.g. Luterbacher et al 2004), based on proxy records, have previously been generated assuming that spatial temperature covariance across the region behaves in the past in the same way as it does in the observational period. This strategy bears the risk of artificially identifying the same patterns of variability as presently observed and overlooking periodically occurring modes of internal climate variability, that are not uniformly spatio-temporally expressed. Here, we construct regional proxy composites for Europe which are not constrained by the modes of variability expressed in the 20th century, and should thus broadly represent coherent regional summer temperatures back through time, independent from present modes of variability. The proxy data set analysed was provided by the efforts of the EU 6th Framework Millennium project. Proxy data are dominated by tree ring width, density and annual height increment. Four composites are used describing summer temperatures in the Arctic, Central, Pyrenean and Alpine zones of Europe. The proxy data sets cover the period AD 1260-1996. We jointly analyse an ensemble of simulations with global climate models participating in the Climate Model Intercomparison Project (CMIP5) included in the 5th Assessment report of the Intergovernmental Panel on Climate Change (IPCC) covering the period AD 850-2005, with the above aims in mind. The climate models were driven by estimations of the main external forcings. The implementations of these forcings may vary among simulations, depending on the different estimates used and on the structure of the models themselves. We analyse three simulations (CCSM4, IPSL, MPI-ESM) that, at the time of writing, provide daily data over the period AD 850-2005 obtained with the very same model version through the whole period. The analysis of both proxy and model data allowed us to more precisely identify the behaviour of the internal climate mode identified.

Gagen, Mary; Zorita, Eduardo; McCarroll, Danny; Loader, Neil; Young, Giles; Robertson, Iain

2014-05-01

74

Development of The Convective-boundary Layer On A Coastal Site: Summer and Winter Field Measurements.  

NASA Astrophysics Data System (ADS)

Within the framework of the EU project RECAB ("Regional Assessment and Model- ing of the Carbon Balance of Europe", EVK2-1999-00236), during July and December of 2001, convective boundary-layer measurements were performed systematically for several days at the coastline near El Saler (Valencia, Spain). A tethersonde sound- ing system was used, with a 1000 m maximum altitude. The measurement strategy included the realization of different profiles during the day: before or about sunrise to determine the characteristics of the drainage flow; at about the time of maximum boundary-layer development after noon; and in the afternoon-evening, to show the collapse of the diurnal flow. The objective was to document experimentally the struc- ture and daily evolution of the coastal boundary layer in the area, as well as to show seasonal variability in response to differences in mesoscale forcing. One of the most important aspects registered in the profiles, and expanding the previous evidences on the western Mediterranean coast, is the intense compensatory sinking on the coast oc- curring within the general subsidence process related to the persistent high pressure system in these latitudes during the summer period in response to the development of the sea breeze coastal cycles. This extra sinking, not present in the winter mea- surements (due to the fact that in this period meteorological processes are dominated by higher scale structures), gives rise to a rich thermal structure in the first hundreds meters of the atmosphere, creating intense superadiabatic lapse rates (a very strati- fied structure can often be appreciated, where different more-or-less uncoupled layers persist), which suppose an important barrier to the vertical diffusion of any surface emissions. This fact is very important for understanding the general process of the surface-atmosphere interchange mechanisms, and especially for modeling such pro- cesses with simple mixing layer schemes.

Mantilla, E.; Sanz, M. J.; Millán., M. M.

75

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

NASA Technical Reports Server (NTRS)

The sensitivities of convective storm structure and intensity to changes in the altitudes of the prestorm environmental lifted condensation level and level of free convection axe studied using a full-physics three-dimensional cloud model. Matrices of simulations are conducted for a range of LCL=LFC altitudes, using a single moderately-sheared curved hodograph trace in conjunction with 1 convective available potential energy values of either 800 or 2000 J/kg, with the matrices consisting of all four combinations of two distinct choices of buoyancy and shear profile shape. For each value of CAPE, the LCL=LFC altitudes are also allowed to vary in a series of simulations based on the most highly compressed buoyancy and shear profiles for that CAPE, with the environmental buoyancy profile shape, subcloud equivalent potential temperature, subcloud lapse rates of temperature and moisture, and wind profile held fixed. For each CAPE, one final simulation is conducted using a near optimal LFC, but a lowered LCL, with a neutrally buoyant environmental thermal profile specified in between. Results show that, for the buoyancy-starved small-CAPE environments, the simulated storms are supercells and are generally largest and most intense when LCL=LFC altitudes lie in the approximate range 1.5-2.5 km above the surface. The simulations show similar trends for the shear-starved large-CAPE environments, except that conversion from supercell to multicell morphology frequently occurs when the LCL is high. For choices of LCL=LFC height within the optimal 1.5-2.5 km range, peak storm updraft overturning efficiency may approaches unity relative to parcel theory, while for lower LCL=LFC heights, overturning efficiency is reduced significantly. The enhancements of overturning efficiency and updraft diameter with increasing LFC height are shown to be the result of systematic increases in the mean equivalent potential temperature of the updraft at cloud base. For the shear-starved environments, the tendency for outflow dominance is eliminated, but a large overturning efficiency maintained, when a low LCL is used in conjunction with a high LFC. The result regarding outflow dominance at high LCL is consistent with expectations, but the beneficial effect of a high LFC on convective overturning efficiency has not previously been widely recognized. The simulation findings here also appear to be consistent with statistics from previous severe storm environment climatologies, but provide a new framework for interpreting those statistics.

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

2001-01-01

76

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

NASA Technical Reports Server (NTRS)

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

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

2010-01-01

77

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

78

Near-Surface Vortex Structure in a Tornado and in a Sub-Tornado-Strength Convective-Storm Vortex Observed by a Mobile, W-Band Radar during VORTEX2  

E-print Network

Near-Surface Vortex Structure in a Tornado and in a Sub-Tornado-Strength Convective-Storm Vortex Verification of the Origins of Rotation in Tornadoes Experiment (VORTEX2) field campaign, a very high-resolution, mobile, W-band Doppler radar collected near-surface (#200 m AGL) observations in an EF-0 tornado near

Xue, Ming

79

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

Microsoft Academic Search

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

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

2005-01-01

80

Electron and proton radiation belt dynamic simulations during storm periods: A new asymmetric convection-diffusion model  

Microsoft Academic Search

Using a convection-diffusion theory, we give the first results from a four-dimensional model of electron and proton radiation belts. This work is based on the numerical solution of a convection-diffusion equation taking into account (1) for protons, the deceleration of protons by the free and bounded thermospheric and ionospheric electrons, the charge exchange loss process, radial and azimuthal transports, and

S. Bourdarie; D. Boscher; T. Beutier; J.-A. Sauvaud; M. Blanc

1997-01-01

81

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

NASA Astrophysics Data System (ADS)

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

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

2014-06-01

82

Convective Modes for Significant Severe Thunderstorms in the Contiguous United States. Part I: Storm Classification and Climatology  

E-print Network

Convective Modes for Significant Severe Thunderstorms in the Contiguous United States. Part I- ameter), significant wind ($65-kt thunderstorm gusts), and tornadoes were filtered by the maximum event 901 tornado and significant severe thunderstorm events, representing 78.5% of all such reports

83

Thyroid storm  

MedlinePLUS

Thyrotoxic storm; Hyperthyroid storm; Accelerated hyperthyroidism ... Thyroid storm occurs in people with untreated hyperthyroidism. It is usually brought on by a major stress such as trauma, heart attack, or infection. Thyroid storm is very rare.

84

10–25–day intraseasonal variations of convection and circulation associated with thermal state of the western Pacific warm pool during boreal summer  

Microsoft Academic Search

This study focuses on the characteristics of 10–25–day oscillation associated with the interannual variability of the thermal\\u000a state in the western Pacific warm pool. The time series of 10–25–day oscillation shows a distinct feature between warm (WARM\\u000a case) and cold (COLD case) summers over the western Pacific warm pool. The significant negative relationship between the time\\u000a series of 10–25–day convection

Ren Baohua; Huang Ronghui

2002-01-01

85

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

86

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

Microsoft Academic Search

A comparison of the stable-isotope signatures of spring waters, snow, snowmelt, summer (July thru September) rain, and cool season (October thru June) rain indicates that the high-intensity, short-duration summer convective storms, which contribute approximately a third of the annual precipitation to the Spring Mountains, provide only a small fraction (perhaps 10%) of the recharge to this major upland in southern

Isaac J. Winograd; Alan C. Riggs; Tyler B. Coplen

1998-01-01

87

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

NASA Astrophysics Data System (ADS)

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

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

2014-09-01

88

Storm Prediction Center  

NSDL National Science Digital Library

The Storm Prediction Center (SPC) is an agency of the National Oceanic and Atmospheric Administration (NOAA) National Weather Service. Materials available on the website include current weather watches, mesoscale discussions, convective outlooks, six-hour thunderstorm outlooks, and fire weather forecasts; research publications, experimental products and techniques; weather information including watch/warning maps, climatological data, and current radar; and a section on tornadoes. There is also an archive of weather images, and sections on the organization and history of the Center.

89

Moist Convection  

NASA Astrophysics Data System (ADS)

On Jupiter there is little doubt that the water condensation level is the seat of moist convective activity. Two major differences between Earth and Jupiter are the importance of the relatively high molecular weight of water on Jupiter and the altered bottom boundary condition on Jupiter. In addition, the triggering mechanism for convection by large scale motion is not yet understood. On Saturn the Great Storm came at a good time for Cassini observations, and the most interesting is the reversal in direction of the vertical motion tracers parahydrogen and potential temperature. Uranus and Neptune appear, on the basis of much less information, to be more exotic. With a high degree of uncertainty we here conjecture that moist convection on these planets is affected by hydrogen ortho-para latent heat in addition to water and methane and that intermittency is the outcome in both the spatial and temporal domains.

Gierasch, Peter J.

2014-11-01

90

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

NASA Technical Reports Server (NTRS)

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

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

1989-01-01

91

City of San Diego Water Quality Monitoring Summer Internship The City of San Diego's Transportation and Storm Water Department is looking for  

E-print Network

, and others. The work can be very physical, often requiring hiking into canyons via steep, rocky hillsides the summer, paid, training provided, safety toe boots provided, and flexible in the event someone has

Wang, Deli

92

Magnetic Storms  

NSDL National Science Digital Library

This is a lesson to introduce the Kp index, a common numerical indicator of magnetic storminess. Learners will access and analyze Kp index plots of magnetic storm strength and determine the relative frequency of stronger versus weaker magnetic storms during years of maximum solar activity. This resource is activity 13 from the Magnetic Mysteries of the Aurora teachers guide. Internet access is required for this activity.

93

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

NASA Technical Reports Server (NTRS)

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

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

2007-01-01

94

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

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

2014-04-01

95

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

NASA Technical Reports Server (NTRS)

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

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

2011-01-01

96

Gravity wave initiated convection  

NASA Technical Reports Server (NTRS)

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

Hung, R. J.

1990-01-01

97

SUMMER CALENDAR Summer 2006  

E-print Network

SUMMER CALENDAR 2006 Summer 2006 Monday..........................June 05 .........................Summer 2006 Term Begins Monday..........................June 05 .........................First Day, please visit ** http://www.sjsu.edu/academic_programs/calendars/academic_calendar #12;2006 Summer 1 2 3 4

Su, Xiao

98

Dust Storm  

Atmospheric Science Data Center

article title:  Elevated Dust over the Middle East     View ... on April 11, 2004 (top panels) contrast strongly with the dust storm that swept across Iraq and Saudi Arabia on May 13, 2004 (bottom ... (MISR) depict both the abundance of airborne dust, and its height above the surface. The natural-color views at left ...

2013-04-16

99

Monitoring and Understanding Trends in Extreme Storms: State of Knowledge  

E-print Network

The state of knowledge regarding trends and an understanding of their causes is presented for a specific subset of extreme weather and climate types. For severe convective storms (tornadoes, hailstorms, and severe ...

Kunkel, Kenneth E.

100

Characteristics of ionospheric storms in East Asia  

NASA Astrophysics Data System (ADS)

???The ionosphere experiences intense response during the geomagnetic storm and it varies with latitude and longitude. The DPS-4 digisonde measurements and GPS-TEC data of ionospheric stations located at different latitudes in the longitudinal sector of 90-130E during 2002 to 2012 were analyzed to investigate the ionospheric effects in the different latitude of East Asia during geomagnetic storm. About 70 geomagnetic storms are selected according to the Dst index and observed data and they are in different seasons and different solar activity levels. A few quiet days’ averages of data before geomagnetic storm were used as the undisturbed level. Results show that for the middle and high latitude, the short-lived positive disturbance associated with the initial phase of the every storm was observed in each season and then the disturbances were negative till the termination of storm. At the low latitude, storm-time disturbances of foF2 have obvious diurnal, seasonal and solar cycle characteristics. Generally, geomagnetic activity will cause foF2 to increase at daytime and decrease at nighttime except for the summer in low solar activity period. The intensity of response of foF2 is stronger at nighttime than that at daytime. The negative ionospheric storm effect is the strongest in summer and the positive ionospheric storm effect is the strongest in winter. In high solar activity period, the diurnal variation of the response of foF2 is very pronounced in each season, and the strong ionospheric response can last several days. In low solar activity period, ionospheric response has very pronounced diurnal variation in winter only. It’s notable that geomagnetic activities occurred at local time nighttime can cause stronger and longer responses of foF2 at the low latitude. All in all, the obvious negative phase ionospheric storms often occurred at the low latitude. Moreover a notable phenomenon was observed for the low latitude, there are the intensive oscillations of foF2 occurring during the main storm phase of enhanced storm in Hainan, and it occurred in the morning generally. For the TEC data, strong disturbances can be observed simultaneously from high latitude to low latitude during the main phase of some storms. Generally strong/weak storms can cause the negative/positive phase storms of TEC in the low latitude and which are obvious in the daytime for the summer and winter and in the period from noon to midnight for the equinox. The differences of the responses of foF2 and TEC are also investigated.

Wang, Xiao; Wang, Guojun; Shi, Jiankui

101

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

102

Storm morphology and electrification from CHUVA-GLM Vale do Paraiba field campaign  

NASA Astrophysics Data System (ADS)

CHUVA [Cloud processes of tHe main precipitation systems in Brazil: A contribUtion to cloud resolVing modeling and to the GPM (GlobAl Precipitation Measurement)] Project is a series of itinerant field campaigns with the objective of characterizing the main precipitating systems observed in Brazil as a support for Global Precipitation Measurement (GPM) mission. The fourth field campaign was conducted at Vale do Paraiba in São Paulo, Brazil, from 1 November 2011 to 31 March 2012. For this specific field experiment, several lightning location systems (LLS) were deployed as part of GOES-R Geostationary Lightning Mapper (GLM) and MTG Lightning Imager (LI) pre-launch activities, resulting in a joint effort between INPE, USP, NOAA, NASA, EUMETSAT and several vendors of operational LLS for network intercomparison and GLM and LI proxy data generation. Among these networks, 4 of them detect total (intra-cloud and cloud-to-ground) lightning, including a Lightning Mapping Array (LMA), allowing a detailed description of the cloud electrification. To depict precipitating weather systems, CHUVA uses a mobile XPOL Doppler Radar, micro-rain radars, disdrometers, rain gauges, microwave radiometer, Lidar, and a GPS network for water vapor retrievals. Also, Vale do Paraíba and São Paulo are covered by 3 operational S-band radars. The precipitation data collected by these radars and the lightning detected by the LLS were grouped in a structure of storm features built by tracking the precipitating systems and its associated lightning. This storm feature database makes it easier to group similar convective systems and compare them in terms of area, lifetime, rainfall and convection intensity, lightning activity, and more. During this field experiment a large variety of cloud systems were sampled: cold fronts, squall lines, the South Atlantic Convergence Zone (SACZ) and local convective systems. Microphysical characteristics (such as hydrometeor identification and ice/water mass) of these summer 2011-2012 precipitating systems can be inferred from the X-Pol and 3 operational S-band radars, and the LLS provide detailed information about the storms electrical activity (such as charge centers and lighting propagation processes). We will summarize the results from this experiment providing an in-depth study of the relationship between the storm type and its microphysical-electrical characteristics by presenting the role of storm morphology on cloud electrification, rainfall and severe weather (hail and damaging winds) production. Also, this storm feature database will provide an easy access to CHUVA data for case studies and GLM and LI activities.

Albrecht, R. I.; Morales, C.; Lima, W. F.; Biscaro, T. S.; Mello, I. B.

2013-12-01

103

Modeling "dusk-effect" during the main phase of geomagnetic storm  

NASA Astrophysics Data System (ADS)

Among the positive ionospheric disturbances which have appeared at the mid-or high latitudes during the main phase of magnetic storm, the evening electron density enhancements attract considerable interest. Usually those enhancements known as the "dusk" effect were observed in the subauroral and auroral ionosphere. Therefore it was suggested that moving auroral oval towards equator during the main phase of magnetic storm is the reason of "dusk" effect. The following observations by incoherent radar system at Millstone-Hill (American longitudinal sec-tor) made it possible to describe in details variations of the main characteristics of this event. At present it is established that "dusk" effect is significantly observed in summer and occurs more frequently in the course of the high geomagnetic activity periods. From the point of view of modern aeronomy the formation of abnormal electron density enhancements in evening ionosphere may be due to action of three principal factors: (i) magnetospheric convection and energetic electron precipitations; (ii) lifting of the F2-layer under the action of enhanced ther-mospheric wind, blowing towards equator and electromagnetic drift; (iii) propagation towards low latitudes of large scaled thermospheric waves, resulting in quick changes of thermospheric composition. The numerical model of ionosphere and plasmasphere was used, in which the vari-ations of the convection velocity, electron precipitation and thermospheric wind corresponded to the storm scenario. It was established following: -"dusk effect" takes place at the mid-and subauroral latitudes of the American longitudinal sector whereas it is at the subauroral latitudes of the Asia longitudinal sector; -the magnetospheric convection and energetic electron precipitations are considerable importance in the formation of "dusk effect" at the subauroral latitudes of the both American and Asia sectors; -thermospheric wind is responsible for the "dusk effect" at the midlatitudes of the American sector and it doesn't manifest itself in the Asia longitudinal sector.

Tashchilin, Anatoly; Romanova, Elena

104

30–60-day oscillations of convection and circulation associated with the thermal state of the western Pacific warm pool during boreal summer  

Microsoft Academic Search

This study focuses on the characteristics of the 30–60-day oscillation (MJO) associated with the interannual variability of\\u000a the thermal state in the western Pacific warm pool. The composite results show that the amplitude of MJO convection over the\\u000a tropical western Pacific tends to intensify (reduce) in the WARM (COLD) case. The negative correlations between MJO convection\\u000a in the WARM and

Ren Baohua; Huang Ronghui

2003-01-01

105

Effective Factors in the Development of Deep Convective Clouds over the Wet Region of Eastern China during the Summer Monsoon Season  

Microsoft Academic Search

A two-dimensional cloud-resolving model, including a supply of sensible and latent heat fluxes from the surface, is used to study the development of deep convective clouds over a southern region far from the Meiyu front (wet region) of eastern China. Some deep convective clouds were observed during the latter half of the GAME\\/HUBEX IOP (GEWEX Asian Monsoon Experiment\\/Huaihe River Basin

Taro SHINODA; Hiroshi UYEDA

2002-01-01

106

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...

107

Seamless Probabilistic Forecasting of Convective Storms  

Microsoft Academic Search

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 (\\

G. C. Craig

2009-01-01

108

Principles of Convection II: Using Hodographs  

NSDL National Science Digital Library

This module provides a basic understanding of how to plot and interpret hodographs, with application to convective environments. Most of the material previously appeared in the CD module, Anticipating Convective Storm Structure and Evolution, developed with Dr. Morris Weisman. Principles of Convection II: Using Hodographs includes a concise summary for quick reference and a final exam to test your knowledge. The module comes with audio narration, rich graphics, and a companion print version.

Comet

2003-10-28

109

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

110

STORM TIDE SIMULATIONS FOR HURRICANE HUGO (1989): ON THE SIGNIFICANCE OF INCLUDING INLAND FLOODING AREAS  

E-print Network

STORM TIDE SIMULATIONS FOR HURRICANE HUGO (1989): ON THE SIGNIFICANCE OF INCLUDING INLAND FLOODING Florida Orlando, Florida Summer Term 2004 #12;ABSTRACT In this study, storm tides are simulated element models with triangular elements are applied in order to simulate the storm tides, allow

Central Florida, University of

111

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

SciTech Connect

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

Fankhauser, J.C.; Crook, N.A.; Tuttle, J.; Miller, L.J.; Wade, C.G. [NCAR, Boulder, CO (United States)] [NCAR, Boulder, CO (United States)

1995-02-01

112

Sensitivity of RegCM4.3 two convection schemes on Indian summer monsoon for the South Asia CORDEX domain  

NASA Astrophysics Data System (ADS)

Regional climate models can be used to examine the impact of global warming at the regional level for the possible emission scenarios. According to IPCC AR4, a number of studies noticed large inter model differences leading to large uncertainties in the projected future changes in different aspects of monsoon rainfall. The aim of this study to understand the different response of similarly forced model RegCM4.3 with different convection scheme over the Ocean. In this study, RegCM4.3 is used to generate the climate scenarios for South Asia CORDEX domain using boundary forcing of global coupled climate models GFDL-ESM2M and MPI-ESM-MR in control runs and two emission scenarios RCP4.5 and RCP8.5 obtained from CMIP5 archive. Emanuel convective parameterization scheme has been used over the land in all the experiments. Over the Ocean, experiments are designed using both Emanual and Grell convection schemes. Rest of the model configuration is based on the different sensitivity experiments conducted to reduce the model temperature and precipitation biases. The model has been integrated at 50km resolution starting from the initial condition of 1st Jan 1970 and the climate simulation continued till 1st Jan 2100. Results indicate that all India JJAS mean temperature change is consistent with clear projection of warming, whereas the projected JJAS precipitation change shows large spread and uncertainty in trends. Even the similar forcing experiments with difference only in the convective scheme over ocean show large difference in their projected precipitation. Climatology of JJAS precipitation over Indian land and low level westerlies for the historical period (1979-2005) is well represented. However, there are differences in the precipitation distribution at regional level within the experiments mainly over the Northwest and southern part of Peninsular India. In case of Emanuel over ocean, enhanced convection over Indian land is mainly associated with the weak westerlies over the Bay of Bengal. The positive anomalies of westerly jet are captured over the Arabian Sea in both the cases where Grell convection over ocean is used in RegCM4.3. Grell scheme over ocean has significantly improved the pattern of westerly flow in RegCM4.3 simulations forced with the considered GCMs.

Mamgain, Ashu; Mariotti, Laura; Coppola, Erika; Giorgi, Filippo; Dash, Sushil Kumar

2013-04-01

113

Cassini/CIRS Observations of Temperatures in Saturn's Northern Storm Region  

NASA Astrophysics Data System (ADS)

In early December 2010, a large convective storm appeared in Saturn's northern hemisphere, centered near 40°N planetographic at the center of a westward jet (Sanchez-Lavega et al., 2011; Fisher et al. 2011). Storms of the observed magnitude, referred to as Great White Spots (GWS), are rare on Saturn, historically occurring once per Saturn year (30 Earth years), at equatorial or mid-northern latitudes during northern summer; the current storm is unusual in occurring during northern spring, roughly one season earlier than previous GWS outbursts. Thermal infrared observations, both groundbased and from the Cassini Composite Infrared Spectrometer (CIRS) orbiting Saturn, taken six weeks after the appearance of the storm, revealed significant changes to the thermal structure of Saturn's northern hemisphere (Fletcher et al., 2011). Cold temperatures were measured at the location of the disturbance in both the upper troposphere and stratosphere, and, surprisingly, hot spots to the east and west of the disturbance longitude with temperature contrasts of 16K, much larger than usual zonal temperature contrasts on Saturn. CIRS has continued to observe the latitude of the storm at one to two month intervals. These observations typically cover an approximately 10° wide latitude strip over one or two rotations of Saturn at a spatial resolution of 2° of arc in the CIRS mid-IR focal planes (600-1400 cm-1, 7-16?m). From these observations, we can retrieve temperatures in the upper troposphere between 50 and 200 mbar, and in the middle stratosphere between ~0.2 and 10 mbar. These observations show that temperatures in the stratospheric hot spots continued to increase through May 2011, when temperatures reached a peak of over 220 K, following the merger of two hot spots into one, with zonal temperature contrasts of 70 K. By mid-July, the maximum temperature in the hot spot had decreased to just under 200K. Furthermore, in May and July, the peak temperatures were at a pressure roughly two scale heights larger (lower in altitude) than in earlier observations - 2 mbar compared to 0.4 mbar. In the upper troposphere, temperature perturbations associated with the storm are around 5 to 10 K, larger than seen on Saturn prior to the storm, but much smaller than the temperature variations seen in the stratosphere.

Achterberg, R. K.; Hesman, B. E.; Bjoraker, G. L.; Fletcher, L.; Conrath, B. J.; Gierasch, P. J.; Flasar, F. M.

2011-12-01

114

Temperature measurements of a Martian local dust storm  

NASA Technical Reports Server (NTRS)

A technique for estimating the ground and near-ground atmospheric temperatures within a Martian local dust storm is presented. It is applied to soundings taken by the Viking orbiter infrared thermal mapper (IRTM) instrument at four times-of-day for one storm. Essentially, a comparison is made between infrared radiances emerging from the storm interior and those from the region surrounding the storm. Particle extinction properties are assumed to be independent of position in the storm region, and scattering properties must be selected arbitrarily. For the storm studied here, the ground temperature in the interior is at least 6 K cooler, whereas the near-ground atmospheric temperature may be less than or comparable to, those of the surroundings. The thermal structure of the storm interior did not change measurably between 11.5 and 16.6 hours local time. These observations favor theories of dust storm development in which regional winds rather than local, dust-driven convection initiate the mobilization of dust from the surface. It is also concluded that the optical properties of dust particles in this local storm differ from those observed by Mariner 9 during the 1971-1972 global dust storm.

Kahn, Ralph

1995-01-01

115

Spectrum of infrasound radiation from supercell storms  

E-print Network

We consider the generation of acoustic waves by turbulent convection and perform spectral analysis of a monopole source of sound related to the heat production by condensation of moisture. A quantitative explanation of the correlation between intensity of infrasound generated by supercell storms and later tornado formation is given. It is shown that low lifting condensation level (LCL) and high values of convective available potential energy (CAPE), which are known to favor significant tornadoes, also lead to a strong enhancement of supercell's low frequency acoustic radiation.

Akhalkatsi, Mariam

2010-01-01

116

Flow over Heated Terrain. Part II: Generation of Convective Precipitation  

E-print Network

indicate that precipitating convection was more likely to be generated downwind of ridges than upwind of them. Initiation of these storms was more likely downwind of ridges with their long axis parallel to the wind direction than downwind of ridges...

Tucker, Donna F.; Crook, N. Andrew

2005-09-01

117

Kinetic energy budget studies of areas of convection  

NASA Technical Reports Server (NTRS)

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

Fuelberg, H. E.

1979-01-01

118

Summer 2014 Fees Undergraduate Summer  

E-print Network

Summer 2014 Fees Undergraduate Summer Fees *Charged per Credit Hour* Resident Non-Resident Summer Academic Fee $550 $1,307 Information Technology Fee $10 $10 Other Required Summer Fees *Charged Per Session* Summer School Fee $5 $5 Software License Fee $6 $6 Health Fee* $54 Summer 1 and/or Summer 2 or $108 Long

Stuart, Steven J.

119

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

120

STORM WATER Residential  

E-print Network

STORM WATER QUALITY HOTLINE UCSC Residential Car Washing http THAT MAY CAUSE ENVIRONMENTAL HARM TO THE STORM WATER QUALITY HOTLINE: (831) 459-2553. LIKE US ON FACEBOOK AT UCSC STORM WATER MANAGEMENT PROGRAM! DID YOU KNOW? PRACTICAL SOLUTIONS > USE A COMMERCIAL CAR WASH

California at Santa Cruz, University of

121

Test and evaluation plan for the Centralized Storm Information System  

NASA Technical Reports Server (NTRS)

The installation of the Centralized Storm Information System (CSIS) at the NOAA operational complex in Kansas City, Missouri is described. This complex includes the National Severe Storms Forecast center and a Satellite Field Service Station which is denoted in this research plan as NSSFC. CSIS computers will act in concert to merge analyze the many data sets needed to forecast severe convective storms. Specific aspects of CSIS are evaluated against the CSIS objectives. The functions to be evaluated characterize the attributes of a generalized interactive computer system. A major development in the CSIS program will allow communication between CSIS and the NSSFC Eclipse computer.

1985-01-01

122

Storms in Space  

NASA Astrophysics Data System (ADS)

Introduction; The cast of characters; Vignettes of the storm; 1. Two kinds of weather; 2. The saga of the storm; 3. Weather stations in space; 4. Lights in the night: the signature of the storm; 5. A walking tour of the magnetosphere; 6. The sun: where it all begins; 7. Nowcasting and forecasting storms in space; 8. Technology and the risks from storms in space; 9. A conversation with Joe Allen; 10. Manned exploration and space weather hazards; 11. The present and future of space weather forecasting; Mathematical appendix. A closer look; Glossary; Figure captions.

Freeman, John W.

2012-11-01

123

Impact of domain size on the simulation of Indian summer monsoon in RegCM4 using mixed convection scheme and driven by HadGEM2 - Impact of domain size on ISM simulations  

NASA Astrophysics Data System (ADS)

In this study, a smaller domain over India alone and a larger South Asia (SA) domain have been used in the Regional Climate Model version 4.2 (RegCM4.2) to examine the effect of the domain size on the Indian summer monsoon simulations. These simulations were carried out over a period of 36 years at 50 km horizontal resolution with the lateral boundary forcings of the UK Met Office Hadley Centre Global Circulation Model Version 2.0. Results show that the Indian summer monsoon rainfall is significantly reduced when the domain size for the model integration is reduced from SA to the Indian domain. In case of SA domain simulation, the Equitable Threat Scores have higher values in case of very light, light and moderate rainfall events than those in case of the Indian domain simulation. It is also found that the domain size of model integration has dominant impact on the simulated convective precipitation. The cross-equatorial flow and the Somali Jet are better represented in the SA simulation than those in the Indian domain simulation. The vertically integrated moisture flux over the Arabian Sea in the SA domain simulation is close to that in the NCEP/NCAR reanalysis while it is underestimated in the Indian domain simulation. It is important to note that when RegCM4.2 is integrated over the smaller Indian domain, the effects of the Himalayas and the moisture advection from the Indian seas are not properly represented in the model simulation and hence the monsoon circulation and associated rainfall are underestimated over India.

Dash, S. K.; Pattnayak, K. C.; Panda, S. K.; Vaddi, Deepika; Mamgain, Ashu

2014-12-01

124

Observations and Fine-Grid Simulations of a Convective Outbreak in Northeastern Spain: Importance of Diurnal Forcing and Convective Cold Pools  

Microsoft Academic Search

The life cycle and interactions of a series of convective systems that developed in northeastern Spain during the afternoon of 7 August 1996 are examined based on remote sensing products, surface observations, and numerical simulations. Most of the convection was organized in two mesoscale convective systems (MCSs) and a line of storms attached to the Pyrenees Mountains. One of these

R. Romero; C. A. Doswell; R. Riosalido

2001-01-01

125

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

126

Mantle Convection  

NSDL National Science Digital Library

This page discusses thermal convection as it applies to the Earth's mantle and includes three QuickTime movies for three different cases of convection: heating from below, heating from within, and a combination of the two.

H. Schmeling

127

Cloud-to-Ground Lightning throughout the Lifetime of a Severe Storm System in Oklahoma  

Microsoft Academic Search

Cloud-to-ground (CG) lightning data are examined relative to digitized radar data for a storm system that occurred in Oklahoma on 26 May 1985. This system evolved through three stages: 1) two lines of cells, one near the dryline and the other 60 km ahead of it; 2) a supercell storm; and 3) a mesoscale convective system (MCS). The behavior of

Mark A. Shafer; Donald R. MacGorman; Frederick H. Carr

2000-01-01

128

Dust Lofting and Ingestion by Supercell Storms ROBERT B. SEIGEL AND SUSAN C. VAN DEN HEEVER  

E-print Network

Dust Lofting and Ingestion by Supercell Storms ROBERT B. SEIGEL AND SUSAN C. VAN DEN HEEVER a need for understanding mineral dust entrainment into moist convection. The goal of this study is to examine the pathways in which nonmicrophysically active mineral dust is entrained into supercell storms

Collett Jr., Jeffrey L.

129

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

130

Satellite observation and mesoscale cloud modeling of St. Anthony, Minnesota storm clouds  

NASA Technical Reports Server (NTRS)

Both rawinsonde data and geosynchronous satellite imagery were used to study the life cycles of St. Anthony, Minnesota's severe convective storms. Cloud modeling, with input sounding data from Saint Cloud, Minnesota, and rapid-scan imagery from GOES were used to investigate storm cloud formation, development and dissipation. Comparisons were made among the seven groups of severe storms which produced an outbreak of 30 tornadoes across the United States.

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

1989-01-01

131

Simulations of phase space distributions of storm time proton ring current  

Microsoft Academic Search

The authors use results of guiding-center simulations of ion transport to map phase space densities of the stormtime proton ring current. They model a storm as a sequence of substorm-associated enhancements in the convection electric field. Their pre-storm phase distribution is an analytical solution to a steady-state transport model in which quiet-time radial diffusion balances charge exchange. This pre-storm phase

Margaret W. Chen; Larry R. Lyons; Michael Schulz

1994-01-01

132

Subtropical Storm Andrea  

NASA Technical Reports Server (NTRS)

The circling clouds of an intense low-pressure system sat off the southeast coast of the United States on May 8, 2007, when the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA's Terra satellite captured this image. By the following morning, the storm developed enough to be classified as a subtropical storm, a storm that forms outside of the tropics, but has many of the characteristics--hurricane-force winds, driving rains, low pressure, and sometimes an eye--of a tropical storm. Although it arrived several weeks shy of the official start of the hurricane season (June 1), Subtropical Storm Andrea became the first named storm of the 2007 Atlantic hurricane season. The storm has the circular shape of a tropical cyclone in this image, but lacks the tight organization seen in more powerful storms. By May 9, the storm's winds reached 75 kilometers per hour (45 miles per hour), and the storm was not predicted to get any stronger, said the National Hurricane Center. Though Subtropical Storm Andrea was expected to remain offshore, its strong winds and high waves pummeled coastal states, prompting a tropical storm watch. The winds fueled wild fires (marked with red boxes) in Georgia and Florida. The wind-driven flames generated thick plumes of smoke that concentrated in a gray-brown mass over Tampa Bay, Florida. Unfortunately for Georgia and Florida, which are experiencing moderate to severe drought, Subtropical Storm Andrea was not predicted to bring significant rain to the region right away, according to reports on the Washington Post Website.

2007-01-01

133

Disturbance of midlatitude electrodynamic parameters due to the magnetospheric convection  

NASA Astrophysics Data System (ADS)

Two case studies of ionospheric disturbances in electric fields, currents, and winds during periods of geomagnetic storms detected by incoherent scatter radar are presented. The disturbances are shown to originate from two distinct physical mechanisms: penetration of electric fields to lower latitudes during times of rapid change in magnetospheric convection; and the action of the disturbed ionospheric dynamo driven by storm induced wind disturbances. One storm illustrates penetrative convection electric fields when the Bz component of the interplanetary fields turns southward and northward. The observed events on the following day are clearly identifiable as the delayed response of the disturbance ionospheric dynamo.

Mazaudier, C.

1984-09-01

134

Toward the Long-range Prediction of Severe Convective Windstorms  

E-print Network

. #12;Fujita and Wakimoto Damaging Winds Scale · Family of downburst clusters (derecho) ­ 1000 km (620 of clusters (Fujita and Wakimoto 1981; Johns and Hirt 1987). #12;Background · A convective downburst) From Fujita and Wakimoto (1981) #12;Convective Downburst Process · Upon initiation of the storm

Kuligowski, Bob

135

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

136

Vorticity imbalance and stability in relation to convection  

NASA Technical Reports Server (NTRS)

A complete synoptic-scale vorticity budget was related to convection storm development in the eastern two-thirds of the United States. The 3-h sounding interval permitted a study of time changes of the vorticity budget in areas of convective storms. Results of analyses revealed significant changes in values of terms in the vorticity equation at different stages of squall line development. Average budgets for all areas of convection indicate systematic imbalance in the terms in the vorticity equation. This imbalance resulted primarily from sub-grid scale processes. Potential instability in the lower troposphere was analyzed in relation to the development of convective activity. Instability was related to areas of convection; however, instability alone was inadequate for forecast purposes. Combinations of stability and terms in the vorticity equation in the form of indices succeeded in depicting areas of convection better than any one item separately.

Read, W. L.; Scoggins, J. R.

1977-01-01

137

Spatial analysis of storm depths from an Arizona raingage network  

NASA Technical Reports Server (NTRS)

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

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

1986-01-01

138

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

139

Large Eddy Simulations of Severe Convection Induced Turbulence  

NASA Technical Reports Server (NTRS)

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

Ahmad, Nash'at; Proctor, Fred

2011-01-01

140

Geomagnetic Storms January 2013  

E-print Network

Geomagnetic Storms January 2013 Empower ResultsTM #12;2 Geomagnetic Storms 2 Pear-Shaped Phenomena Contents Pear-Shaped Phenomena Aon Benfield uses "Pear-shaped phenomena" to refer to relatively low swan events which are defined as "unforeseeable" pear-shaped phenomena (PSP) can be anticipated

Schrijver, Karel

141

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

NASA Technical Reports Server (NTRS)

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

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

1999-01-01

142

Structure of Highly Sheared Tropical Storm Chantal during CAMEX-4  

NASA Technical Reports Server (NTRS)

Tropical Storm Chantal during August 2001 was a storm that failed to intensify over the few days prior to making landfall on the Yucatan Peninsula. An observational study of Tropical Storm Chantal is presented using a diverse dataset including remote and in situ measurements from the NASA ER-2 and DC-8 and the NOAA WP-3D N42RF aircraft and satellite. The authors discuss the storm structure from the larger-scale environment down to the convective scale. Large vertical shear (850-200-hPa shear magnitude range 8-15 m/s) plays a very important role in preventing Chantal from intensifying. The storm had a poorly defined vortex that only extended up to 5-6-km altitude, and an adjacent intense convective region that comprised a mesoscale convective system (MCS). The entire low-level circulation center was in the rain-free western side of the storm, about 80 km to the west-southwest of the MCS. The MCS appears to have been primarily the result of intense convergence between large-scale, low-level easterly flow with embedded downdrafts, and the cyclonic vortex flow. The individual cells in the MCS such as cell 2 during the period of the observations were extremely intense, with reflectivity core diameters of 10 km and peak updrafts exceeding 20 m/s. Associated with this MCS were two broad subsidence (warm) regions, both of which had portions over the vortex. The first layer near 700 hPa was directly above the vortex and covered most of it. The second layer near 500 hPa was along the forward and right flanks of cell 2 and undercut the anvil divergence region above. There was not much resemblance of these subsidence layers to typical upper-level warm cores in hurricanes that are necessary to support strong surface winds and a low central pressure. The observations are compared to previous studies of weakly sheared storms and modeling studies of shear effects and intensification. The configuration of the convective updrafts, low-level circulation, and lack of vertical coherence between the upper- and lower-level warming regions likely inhibited intensification of Chantal. This configuration is consistent with modeled vortices in sheared environments, which suggest the strongest convection and rain in the downshear left quadrant of the storm, and subsidence in the upshear right quadrant. The vertical shear profile is, however, different from what was assumed in previous modeling in that the winds are strongest in the lowest levels and the deep tropospheric vertical shear is on the order of 10-12 m/s.

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

2006-01-01

143

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

NASA Technical Reports Server (NTRS)

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

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

2002-01-01

144

Arctic Summer Ice Processes  

NASA Technical Reports Server (NTRS)

The primary objective of this study is to estimate the flux of heat and freshwater resulting from sea ice melt in the polar seas. The approach taken is to examine the decay of sea ice in the summer months primarily through the use of spaceborne Synthetic Aperture Radar (SAR) imagery. The improved understanding of the dynamics of the melt process can be usefully combined with ice thermodynamic and upper ocean models to form more complete models of ice melt. Models indicate that more heat is absorbed in the upper ocean when the ice cover is composed of smaller rather than larger floes and when there is more open water. Over the course of the summer, floes disintegrate by physical forcing and heating, melting into smaller and smaller sizes. By measuring the change in distribution of floes together with open water over a summer period, we can make estimates of the amount of heating by region and time. In a climatic sense, these studies are intended to improve the understanding of the Arctic heat budget which can then be eventually incorporated into improved global climate models. This work has two focus areas. The first is examining the detailed effect of storms on floe size and open water. A strong Arctic low pressure storm has been shown to loosen up the pack ice, increase the open water concentration well into the pack ice, and change the distribution of floes toward fewer and smaller floes. This suggests episodic melting and the increased importance of horizontal (lateral) melt during storms. The second focus area is related to an extensive ship-based experiment that recently took place in the Arctic called Surface Heat Budget of the Arctic (SHEBA). An icebreaker was placed purposely into the older pack ice north of Alaska in September 1997. The ship served as the base for experimenters who deployed extensive instrumentation to measure the atmosphere, ocean, and ice during a one-year period. My experiment will be to derive similar measurements (floe size, open water, temporal change) using spaceborne SAR data obtained during the summer of 1998, and compare these results with an ocean and ice model of summer melt. Additional information is contained in the original.

Holt, Benjamin

1999-01-01

145

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

2009-01-01

146

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

147

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

NASA Technical Reports Server (NTRS)

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

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

2008-01-01

148

Air-sea interactions during an Arctic storm  

NASA Astrophysics Data System (ADS)

The impacts of increased open water in the Beaufort Sea were investigated for a summer Arctic storm in 2008 using a coupled atmosphere-ice-ocean model. The storm originated in northern Siberia and slowly moved into the Beaufort Sea along the ice edge in late July. The maximum wind associated with the storm occurred when it was located over the open water near the Beaufort Sea coast, after it had moved over the Chukchi and Beaufort Seas. The coupled model system is shown to simulate the storm track, intensity, maximum wind speed and the ice cover well. The model simulations suggest that the lack of ice cover in the Beaufort Sea during the 2008 storm results in increased local surface wind and surface air temperature, compared to enhanced ice cover extents such as occurred in past decades. In addition, due to this increase of open water, the surface latent and sensible heat fluxes into the atmosphere are significantly increased. However, there were no significant impacts on the storm track. The expanded open water and the loss of the sea ice results in increases in the surface air temperature by as much as 8°C. Although the atmospheric warming mostly occurs in the boundary layer, there is increased atmospheric boundary turbulence and downward kinetic energy transport that reach to mid-levels of the troposphere and beyond. These changes result in enhanced surface winds, by as much as ˜4 m/s during the 2008 storm, compared to higher ice concentration conditions (typical of past decades). The dominant sea surface temperature response to the storm occurs over open water; storm-generated mixing in the upper ocean results in sea surface cooling of up to 2°C along the southern Beaufort Sea coastal waters. The Ekman divergence associated with the storm caused a decrease in the fresh water content in the central Beaufort Sea by about 11 cm.

Long, Zhenxia; Perrie, Will

2012-08-01

149

Why do Tornados and Hail Storms Rest on Weekends?  

NASA Technical Reports Server (NTRS)

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

Rosenfeld, Daniel; Bell, Thomas L.

2010-01-01

150

Convection Movies  

NSDL National Science Digital Library

This page, on the website of Stephane Labrosse of ENS Lyon, presents some examples of flow motions resulting from convection calculations in different situations. All are for infinite Prandtl number and free-slip boundary conditions on horizontal surfaces

Stephane Labrosse

151

Dusty gust fronts and their contributions to long-lived convection in West Africa/  

E-print Network

To model and predict the behavior of West African storms and mesoscale convective systems (MCSs), we must understand the life cycle of gust fronts, which invariably accompany thunderstorms and often initiate them. In this ...

McGraw-Herdeg, Michael (Michael P.)

2010-01-01

152

The Numerical Simulation of Orographic Storms  

NASA Astrophysics Data System (ADS)

Recent observational studies of winter storms over the Glamorgan Hills of south Wales (Browning et al., 1974, and Hill et al., 1981) have confirmed the importance of the seeder-feeder mechanism of orographic precipitation enhancement, proposed by Bergeron (1965). However, the latter study also indicated that the sensitivity of the enhancement to the low-level wind speed is much greater than predicted by the seeder-feeder model of Bader and Roach (1977), which simulates only the microphysical processes. A new, dynamic mountain model was used to investigate the hypothesis that mountain wave effects were responsible for this increased wind speed sensitivity. The model, which evolved from the cloud model of Klemp and Wilhelmson (1978), is formulated in terrain-following coordinates. In addition to representing convective and stratiform cloud processes, the model is also capable of accurately simulating moderately nonlinear mountain waves, and is suitable for studying many aspects of orographic storms. The simulations show that orographic clouds significantly alter the airflow over hills and, conversely, that mountain waves strongly influence the moist processes. Wind speed, wind shear, atmospheric stability, and relative humidity are all important factors in the complex scale interactions which occur during orographic storms. The results strongly support the hypothesis that certain mountain wave effects greatly increase the wind speed sensitivity of the Bergeron seeder-feeder mechanism.

Bradley, Michael Morgan

153

Into the Eye of the Storm  

NASA Technical Reports Server (NTRS)

MISR acquired this stereoimage of Hurricane Alberto on August 19, 2000 during Terra orbit 3571. At this time, the storm was located in the North Atlantic Ocean, about 1700 kilometers west of the Azores. According to the National Weather Service, Alberto was increasing in intensity and exhibiting maximum sustained winds of about 165 kilometers per hour.

This stereo 'anaglyph' image was generated using MISR's vertical (nadir)camera plus the 26-degree forward-viewing camera. It is oriented so that the spacecraft's flight path is from left to right. North is at the left. To view the image in 3-D, use red/blue glasses with the red filter over your left eye.

Near the center of the storm, the 'eye' measures about 60 kilometers in diameter. The steep eye wall, where surface winds reach their peak intensity, is very apparent. Convective thunderclouds are present in the storm's spiral arms, and their three-dimensional structure is visible in this stereo view.

MISR was built and is managed by NASA's Jet Propulsion Laboratory, Pasadena, CA, for NASA's Office of Earth Science, Washington, DC. The Terra satellite is managed by NASA's Goddard Space Flight Center, Greenbelt, MD. JPL is a division of the California Institute of Technology.

For more information: http://www-misr.jpl.nasa.gov

2000-01-01

154

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.

155

On extreme geomagnetic storms  

NASA Astrophysics Data System (ADS)

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

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

2014-10-01

156

Superposed epoch analyses of ion temperatures during CME- and CIR/HSS-driven storms  

NASA Astrophysics Data System (ADS)

Coronal mass ejections (CMEs) and corotating interaction regions associated with high speed solar wind streams (CIR/HSSs) drive geomagnetic storms in the terrestrial magnetosphere. Each type of storm driver yields different dynamics of storm evolution. We present results from comparative superposed epoch analyses of global ion temperatures calculated from TWINS energetic neutral atom (ENA) data and simulations using the comprehensive ring current model (CRCM). During the June 2008-April 2012 timeframe, 48 geomagnetic storms (minimum Dst?-40 nT) occurred. Of these, 21 storms were CME-driven and 15 were driven by CIR/HSSs. Superposed epoch analysis results demonstrate that ion temperatures increase during the recovery phase of CIR/HSS-driven storms, while ions are rapidly heated at the commencement of CME-driven storms then cool over the main phase, particularly for intense (minimum Dst?-78 nT) CME-driven storms. Higher energy ions are convected to lower L-shells during CME-driven storms, while CIR/HSS-driven storms tend to have average ion temperatures that are higher on the dayside than nightside.

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

2014-08-01

157

16A.2 CAPS REALTIME 4-KM MULTI-MODEL CONVECTION-ALLOWING ENSEMBLE AND 1-KM CONVECTION-RESOLVING FORECASTS FOR THE NOAA  

E-print Network

at such scales render probabilistic forecast information afforded by high-resolution ensemble forecasting sys: (1) the values and cost-benefit of convection-allowing-resolution ensem- ble versus coarser; (5) the most effective ensemble post-processing and forecast products for the convective storm scales

Xue, Ming

158

Identification of Robust Terminal-Area Routes in Convective Weather  

E-print Network

Convective weather is responsible for large delays and widespread disruptions in the U.S. National Airspace System, especially during summer. Traffic flow management algorithms require reliable forecasts of route blockage ...

Balakrishnan, Hamsa

159

Historically Great Magnetic Storms  

NASA Astrophysics Data System (ADS)

What was the largest geomagnetic storm ever recorded? The question is of interest for both theoretical and practical reasons. The available records of magnetic activity indicate that three of the largest storms (in 1859, 1909, and 1921) occurred before the epoch of systematic high-time-resolution indices initiated by Bartels in 1932. Recent efforts to extend such indices back in time enable us to compare the 1909 and 1921 storms with modern giants such as the March 1989 event. Comparisons are made between early reports of auroras at mid-latitudes and magnetic activity. Overhead aurora are associated with particularly strong magnetic disturbances, e.g., the 3000 nT deflection recorded for the 1859 event in Rome.

Cliver, E. W.

2012-12-01

160

Storm Warning Service  

NASA Technical Reports Server (NTRS)

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

1993-01-01

161

Geomagnetic responses in high latitudes during the storm of july 15—16, 2000  

Microsoft Academic Search

The ionospheric equivalent currents in the high latitudes and the auroral electrojet system during the geomagnetic storm on\\u000a July 15–16, 2000 are analyzed by using geomagnetic data from IMAGE chain. The large-scale vortices of equivalent currents\\u000a are observed in the storm. The vortices on the dusk side of ionosphere correspond to four-celled pattern of plasma convection\\u000a associated with NBZ, region

Gengxiong Chen; Aimin Du; Wenyao Xu; Hongfei Chen; Minghua Hong; Fenglin Peng; Enqi Shi

2002-01-01

162

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

NASA Technical Reports Server (NTRS)

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

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

1990-01-01

163

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

SciTech Connect

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

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

1988-01-01

164

Future changes in extratropical storm tracks and baroclinicity under climate change  

NASA Astrophysics Data System (ADS)

The weather in Eurasia, Australia, and North and South America is largely controlled by the strength and position of extratropical storm tracks. Future climate change will likely affect these storm tracks and the associated transport of energy, momentum, and water vapour. Many recent studies have analyzed how storm tracks will change under climate change, and how these changes are related to atmospheric dynamics. However, there are still discrepancies between different studies on how storm tracks will change under future climate scenarios. Here, we show that under global warming the CMIP5 ensemble of coupled climate models projects only little relative changes in vertically averaged mid-latitude mean storm track activity during the northern winter, but agree in projecting a substantial decrease during summer. Seasonal changes in the Southern Hemisphere show the opposite behaviour, with an intensification in winter and no change during summer. These distinct seasonal changes in northern summer and southern winter storm tracks lead to an amplified seasonal cycle in a future climate. Similar changes are seen in the mid-latitude mean Eady growth rate maximum, a measure that combines changes in vertical shear and static stability based on baroclinic instability theory. Regression analysis between changes in the storm tracks and changes in the maximum Eady growth rate reveal that most models agree in a positive association between the two quantities over mid-latitude regions.

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

2014-08-01

165

Dynamic Reconfiguration of Terminal Airspace During Convective Weather  

E-print Network

Dynamic Reconfiguration of Terminal Airspace During Convective Weather Diana Michalek and Hamsa research has largely focused on enroute airspace in clear weather conditions, the principle of better are often impacted by congestion due to convective weather, especially during summer months when travel

Gummadi, Ramakrishna

166

Recovery from major storms  

SciTech Connect

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

Holeman, J.S.

1980-01-01

167

Storm Report Map  

NSDL National Science Digital Library

This website overlays each day's storms as they occur on a Google Map, pinpointing the location where tornados occurred. The site has data since 5 May 2004, and any day since can be consulted. For particularly impressive sets of tornados, try 2 April 2006 or 12 November 2005.

168

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

169

Magnetic Storms and Aurora  

NSDL National Science Digital Library

This is a lesson to investigate auroras. Learners will plot and compare the amount of energy dissipated by auroras in the northern hemisphere with the recorded Kp index of magnetic storm severity. This is the sixteenth activity in the Exploring the Earth's Magnetic Field: An IMAGE Satellite Guide to the Magnetosphere educators guide.

2012-08-03

170

Weather Stations: Storms  

NSDL National Science Digital Library

In this activity, learners test how cornstarch and glitter in water move when disturbed. Learners compare their observations with videos of Jupiter's and Earth's storm movements. This activity is one station that can be combined with other stations for an hour and half lesson on weather patterns on Jupiter and Earth.

Institute, Lunar A.; Nasa

2011-01-01

171

The Perfect Storm  

NSDL National Science Digital Library

The National Oceanic and Atmospheric Administration (NOAA) provides these two Websites on weather. The second site is narrower in scope but still of interest to weather researchers and to the public at large. Here, NOAA offers historical information, satellite images, and detailed text on the agency's coverage of the now-famous monster storm of October 1991, which sank the Andrea Gail.

172

STORM INLET FILTRATION DEVICE  

EPA Science Inventory

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

173

Time for Dust Storms  

NASA Technical Reports Server (NTRS)

MGS MOC Release No. MOC2-414, 7 July 2003

This is the dusty time of year for Mars. The Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) team has been anticipating for months that late June through July 2003 will be a time of large dust storms and considerable haze. As June turned to July, several large dust storms began popping up. Two examples are shown here in this mosaic of MOC daily global images from June 29, 2003. Near the center of this picture is a large dust storm engulfing southern Isidis Planitia. Toward the upper right (northeast) of the Isidis storm is another event in northern Elysium Planitia.

This view of a portion of Mars is illuminated by sunlight from the left. This is a simple cylindrical map projection, north is up. The large dark feature just left of center is Syrtis Major; the bright oval toward the bottom left is the giant Hellas impact basin, which is more than 2,000 km (more than 1200 miles) across. The white area at the bottom of the picture is the south polar seasonal frost cap, made up mostly of carbon dioxide. The wispy features at the top of the image are clouds over the martian northern plains.

2003-01-01

174

Magnetic Storms in Brazil  

NASA Astrophysics Data System (ADS)

Magnetic storms result from atypical processes generated in the Sun, the interaction between the solar wind and the Earth's magnetosphere and the energization of particles in the magnetosphere. As consequence, magnetic storms may cause problems on radio communication, in satellites, GPS imprecision and induce geomagnetic induced currents that my cause saturation and damage of transformers. Magnetic storms are measured in magnetic observatories, where it is possible to observe large variations in the horizontal magnetic field. These variations are most visible in equatorial or low-latitude magnetograms. In this work, we use low latitude dataset from three magnetic observatories in Brazil: Vassouras (Rio de Janeiro) that presents data since 1915, Tatuoca (Pará) since 1957 and data from a new magnetic observatory that was installed in Pantanal (Brazil) on the 22nd October 2012. Vassouras and Pantanal observatories are in the region of the South Atlantic Magnetic Anomaly. External magnetic field interactions in this region are poorly known due to the lack of magnetic data. Tatuoca observatory is located in another important geomagnetic region: the equatorial electrojet. In this work we present the data processing of the recent geomagnetic time series in Pantanal Observatory and its comparison with Vassouras and Tatuoca observatories in Brazil. We analyse the main characteristics of magnetic storms in these observatories, as the sudden commencement and their duration.

Pinheiro, K.; Siqueira, F.

2013-05-01

175

Magnetospheric Convection near a Drainage Plume  

Microsoft Academic Search

We report on equatorial convection associated with a plasmaspheric drainage plume using simultaneous observations from five satellites. During the early recovery phase of the July 2000 Bastille Day magnetic storm, the Extreme Ultraviolet sensor on the Magnetopause-to-Aurora Global Exploration satellite detected the plume near 16:00–17:00 magnetic local time extending outward to L ? 2.8. The plasmaspheric boundary was near L

Chin S. Lin; Huey-Ching Yeh; Bill R. Sandel; J. Goldstein; Frederick J. Rich; William J. Burke; J. C. Foster

2007-01-01

176

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

177

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

178

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

179

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.

Prueitt, Melvin L. (Los Alamos, NM)

1996-01-01

180

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.

Prueitt, Melvin L. (Los Alamos, NM)

1995-01-01

181

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

182

Yale Summer Session 2013 Summer Faculty Handbook  

E-print Network

Yale Summer Session 2013 Summer Faculty Handbook #12;2013 SUMMER FACULTY HANDBOOK The closing date for material in the Yale Summer Session 2013 Faculty handbook was March 1, 2013. Yale Summer Session #12;ii #12;TABLE OF CONTENTS I. FOREWORD 1 II. YALE SUMMER SESSION A. A Brief History of Yale Summer Session 1 B

183

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

NASA Technical Reports Server (NTRS)

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

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

1988-01-01

184

Kinetic energy budgets in areas of convection  

NASA Technical Reports Server (NTRS)

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

Fuelberg, H. E.

1979-01-01

185

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.

186

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

NASA Technical Reports Server (NTRS)

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

Fok, Mei-Chging; Moore, Thomas

2008-01-01

187

Environmental control of cloud-to-ground lightning polarity in severe storms  

NASA Astrophysics Data System (ADS)

The overwhelming majority of severe storms throughout the contiguous U.S. generate primarily (>75%) negative ground flashes (so-called negative storms). However, a certain subset of severe storms produces an anomalously high (> 25%) percentage of positive ground flashes (so-called positive storms). The frequency of these "anomalous" positive storms varies regionally and seasonally. In some regions (e.g., central and northern plains) and months, these positive storms are common, representing 30% or more of all severe storms. Several past studies have noted that severe storms passing through similar mesoscale regions on a given day exhibit similar cloud-to-ground (CG) lightning behavior. This repeated observation led to the idea that the local mesoscale environment indirectly influences CG lightning polarity by directly controlling storm structure, dynamics, and microphysics, which in turn control storm electrification. Although a few studies have explored this relationship, the exact conditions favoring positive storms are poorly understood. The purpose of this study is to conduct a systematic comparison of the mesoscale environments for positive and negative storms, set in the framework of a testable hypothesis. According to our hypothesis, intense updrafts and associated high liquid water contents in positive storms lead to positive charging of graupel and hail via the non-inductive charging mechanism, an enhanced lower positive charge (or inverted-polarity), and increased frequency of positive CG lightning. We have utilized abundant environmental soundings taken during the International H2O project (IHOP, May-June 2002) to document the relationship between mesoscale environment and dominant CG lightning polarity in the central plains. From hundreds of IHOP soundings, we carefully selected roughly fifty inflow proximity soundings that best represented the mesoscale environment of five (four) negative (positive) storm systems. Mean convective available potential energy (CAPE) estimated in the electrically important mixed phase zone (-10 to -40 degrees Celsius) was significantly higher in positive storms (1210 J kg-1) than in negative storms (957 J kg-1). Positive storms (14.7 m s-1) had noticeably higher mean low-level (0-3 km) shear than negative storms (10.7 m s-1). Interestingly, the mean lifting condensation level (LCL) for positive storms (2079 m) was 1.9 times higher than for negative storms (1121 m). The environmental freezing level (FL) was also lower in positive storms (3777 m) than in negative storms (4070 m). As a result, the mean warm cloud depth (FL-LCL) was dramatically larger in negative storms (2949 m) than in positive storms (1699 m). According to parcel theory, higher mixed phase CAPE directly leads to stronger updrafts and higher liquid water contents in positive storms. Larger low-level shear in positive storms aids in the development of intense low-to-mid level updrafts and enhanced liquid water contents through dynamic forcing. Higher LCL or cloud base height, which is associated with increased parcel size and decreased entrainment of dry air, in positive storms results in more efficient conversion of CAPE into kinetic energy and hence enhanced updraft strength and liquid water content. Reduced warm cloud depth in positive storms may decrease the amount of liquid water that is lost through the collision-coalescence and rainout process in a rising air parcel below the mixed phase zone, effectively increasing the amount of supercooled cloud water that is available for cloud electrification.

Carey, L. D.; Buffalo, K.

2004-12-01

188

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

189

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

NASA Technical Reports Server (NTRS)

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

Lupo, Kevin

2012-01-01

190

Dust Storm, Aral Sea  

NASA Technical Reports Server (NTRS)

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

2002-01-01

191

Severe storm electricity  

NASA Technical Reports Server (NTRS)

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

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

1984-01-01

192

Severe storm electricity  

NASA Technical Reports Server (NTRS)

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

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

1985-01-01

193

Convection Current  

NSDL National Science Digital Library

This demonstration provides an aesthetic way to view convection currents in fluids. Water warmed by an electric circuit mixes with the surrounding cooler water creating turbulence effects that bend light; the resulting swirling shadows can be projected onto a screen. The site provides an explanation of what happens and a simpler method to demonstrate the same effect. Materials needed and assembly instructions are also given. This activity is part of Exploratorium's Science Snacks series.

2006-07-22

194

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

195

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. 5 figures.

Prueitt, M.L.

1994-02-08

196

Defining Coastal Storm and Quantifying Storms Applying Coastal Storm Impulse Parameter  

NASA Astrophysics Data System (ADS)

What defines a storm condition and what would initiate a "storm" has not been uniquely defined among scientists and engineers. Parameters that have been used to define a storm condition can be mentioned as wind speed, beach erosion and storm hydrodynamics parameters such as wave height and water levels. Some of the parameters are storm consequential such as beach erosion and some are not directly related to the storm hydrodynamics such as wind speed. For the purpose of the presentation, the different storm conditions based on wave height, water levels, wind speed and beach erosion will be discussed and assessed. However, it sounds more scientifically to have the storm definition based on the hydrodynamic parameters such as wave height, water level and storm duration. Once the storm condition is defined and storm has initiated, the severity of the storm would be a question to forecast and evaluate the hazard and analyze the risk in order to determine the appropriate responses. The correlation of storm damages to the meteorological and hydrodynamics parameters can be defined as a storm scale, storm index or storm parameter and it is needed to simplify the complexity of variation involved developing the scale for risk analysis and response management. A newly introduced Coastal Storm Impulse (COSI) parameter quantifies storms into one number for a specific location and storm event. The COSI parameter is based on the conservation of linear, horizontal momentum to combine storm surge, wave dynamics, and currents over the storm duration. The COSI parameter applies the principle of conservation of momentum to physically combine the hydrodynamic variables per unit width of shoreline. This total momentum is then integrated over the duration of the storm to determine the storm's impulse to the coast. The COSI parameter employs the mean, time-averaged nonlinear (Fourier) wave momentum flux, over the wave period added to the horizontal storm surge momentum above the Mean High Water (MHW) integrated over the storm duration. The COSI parameter methodology has been applied to a 10-year data set from 1994 to 2003 at US Army Corps of Engineers, Field Research Facility (FRF) located on the Atlantic Ocean in Duck, North Carolina. The storm duration was taken as the length of time (hours) that the spectral significant wave heights were equal or greater than 1.6 meters for at least a 12 hour, continuous period. Wave heights were measured in 8 meters water depth and water levels measured at the NOAA/NOS tide gauge at the end of the FRF pier. The 10-year data set were analyzed applying the aforementioned storm criteria and produced 148 coastal events including Hurricanes and Northeasters. The results of this analysis and application of the COSI parameter to determine "Extra Ordinary" storms in Federal Projects for the Gulf of Mexico, 2012 hurricane season will be discussed at the time of presentation.

Mahmoudpour, Nader

2014-05-01

197

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

198

Convective weather hazards in the Twin Cities Metropolitan Area, MN  

NASA Astrophysics Data System (ADS)

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

Blumenfeld, Kenneth A.

199

Tropical Severe Local Storms  

NSDL National Science Digital Library

The module provides a brief overview of severe local storms in the tropics. Basic ingredients for thunderstorms and assessment of thunderstorm potential from soundings are described. Then properties and hazards of ordinary thunderstorms, multicellular thunderstorms, supercells are reviewed. Conditions conducive to supercell formation in the tropics are examined along with methods of identifying them in radar and satellite images. Supercell and non-supercell tornado properties and formation are described. Finally, tornadoes, waterspouts, and dust devils properties are compared.

2014-09-14

200

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

NASA Astrophysics Data System (ADS)

Research conducted at Polish Institute of Meteorology and Water Management, National Research Institute, in collaboration with Consortium for Small Scale Modeling (COSMO) are aimed at developing new conservative dynamical core for next generation operational weather prediction model. As the result, a new prototype model was developed with dynamical core based on anelastic set of equation and numerics adopted from the EULAG model. An employment of EULAG allowed to profit from its desirable conservative properties and numerical robustness confirmed in number of benchmark tests and widely documented in scientific literature. The hybrid model consists of EULAG dynamical core implemented into the software environment of the operational COSMO model and basic COSMO physical parameterizations involving turbulence, friction, radiation, moist processes and surface fluxes (COSMO-EULAG). The tool is capable to compute weather forecast in mountainous area for the horizontal resolution of 0.28 km and with slopes reaching 60 degrees of inclination. The presentation is focused on two current research topics. First, the model and especially its dynamics-physics coupling is examined within idealized framework for representation of convective flows. The study is based on two complementary convection benchmarks of Weisman and Klemp (Mon. Wea. Rev. 110:504, 1982) and Grabowski et al. (Q. J. R. Meteorol. Soc. 132:317, 2006). While the first experiment can be used to examine a life cycle of a single convective storm structure in COSMO-EULAG model, the second experiment allows to evaluate the model representation of statistical properties of daytime convective development over land, involving convection initiation as well as is transition into a deep phase. The study involves also the comparison of COSMO-EULAG results with results of standard compressible COSMO-Runge-Kutta model to test the suitability of the anelastic dynamical core for operational mesoscale high-resolution NWP. Next, the results of a realistic case study of Alpine summer convection simulated by COSMO-EULAG with very high horizontal resolutions ranging from 2.2 to 0.28km are presented. While the simulations, even with highest resolution, do not require any artificial orography smoothing, the influence of such smoothing on simulation results is investigated. The study shows e.g. a comparison of flow, cloud and precipitation structure, and spectral analyses of horizontal wind fields. The Cosmo-Eulag forecast is also compared with available meteorological information.

Wójcik, Damian; Piotrowski, Zbigniew; Rosa, Bogdan; Ziemia?ski, Micha?

2014-05-01

201

The Tropical Convective Spectrum. 1; Archetypal Vertical Structures  

NASA Technical Reports Server (NTRS)

A taxonomy of tropical convective vertical structures is constructed through cluster analysis of three years of Tropical Rainfall Measuring Mission [TRMM] Precipitation Radar [PR] vertical profiles, their surface rainfall and associated radar-based classifiers (convective/stratiform and bright band existence). archetypal profile types are identified. These include nine convective types, divided into warm, "just cold", midlevel, deep and deep/wet-growth categories, seven stratiform types, divided into warm, "just cold", midlevel and deep categories, three "mixed" types (deep profiles with low reflectivity aloft), and six fragment types (non-precipitating anvils and sheared deep convective profiles). The taxonomy allows for description of any storm or local Convective spectrum by the nine primary convective and stratiform types, a significant reduction over full three-dimensional radar data which nonetheless retains vertical structure information. The analysis provides a quasi-independent corroboration of the TRMM 2A23 convective/stratiform classification. The global frequency of occurrence and contribution to rainfall for the profile types is presented, demonstrating primary rainfall contribution by midlevel glaciated convection and similar depth decaying/stratiform stages. Close correspondence is found between deep convective profile frequency and annualized lightning production. Passive microwave and lightning properties associated with the profiles are reported, and cases presented illustrating known nonuniqueness problems with 85 and 37 GHz brightness temperature pairs (the same pairs corresponding to both convective and stratiform profiles), and how supplementary lightning information might be used to mitigate these problems.

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

2004-01-01

202

Summer Reading  

NASA Astrophysics Data System (ADS)

Summer, a great time for leisure reading, a great time to try something different! Cheryl Baldwin Frech joins regulars Dick Pagni, Brian Coppola, Hal Harris, and Jeff Kovac in providing plenty of suggestions to tempt you.

Pagni, Richard M.; Baldwin Frech, Cheryl; Coppola, Brian P.; Harris, Harold H.; Kovac, Jeffrey

2005-06-01

203

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

204

Heavier summer downpours with climate change revealed by weather forecast resolution model  

NASA Astrophysics Data System (ADS)

The intensification of precipitation extremes with climate change is of key importance to society as a result of the large impact through flooding. Observations show that heavy rainfall is increasing on daily timescales in many regions, but how changes will manifest themselves on sub-daily timescales remains highly uncertain. Here we perform the first climate change experiments with a very high resolution (1.5 km grid spacing) model more typically used for weather forecasting, in this instance for a region of the UK. The model simulates realistic hourly rainfall characteristics, including extremes, unlike coarser resolution climate models, giving us confidence in its ability to project future changes at this timescale. We find the 1.5 km model shows increases in hourly rainfall intensities in winter, consistent with projections from a coarser 12 km resolution model and previous studies at the daily timescale. However, the 1.5 km model also shows a future intensification of short-duration rain in summer, with significantly more events exceeding the high thresholds indicative of serious flash flooding. We conclude that accurate representation of the local storm dynamics is an essential requirement for predicting changes to convective extremes; when included we find for the model here that summer downpours intensify with warming.

Kendon, Elizabeth J.; Roberts, Nigel M.; Fowler, Hayley J.; Roberts, Malcolm J.; Chan, Steven C.; Senior, Catherine A.

2014-07-01

205

METEOR - an artificial intelligence system for convective storm forecasting  

SciTech Connect

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

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

1987-03-01

206

Concentration of Cloud Condensation Nuclei Before and After Convective Storms  

E-print Network

the magnitude of changes that in CCN after a rain event. View of Rain on July 12, 2012View of Rain from Aircraft of particles in air that cloud droplets form on. #12;#12;CCN Counter Lab Calibration Setup #12;CCN Counter Condensation Nuclei (CCN) adjusted to standard temperature and pressure during the 2010 POLCAST3 field project

Delene, David J.

207

Report Concerns: Storm Water Quality Hotline  

E-print Network

Report Concerns: Storm Water Quality Hotline: Please report any concerns, illegal dumping into storm drains, or suspi- cious activities that may cause environ- mental harm to the Storm Water Qual of Carolyn Lagattuta) UC SANTA CRUZ STORM WATER This brochure is created by Joanne Yee, Storm Water

California at Santa Cruz, University of

208

INTRODUCTION TO STORM SURGE Introduction to  

E-print Network

of storm surge. Too many exceptions to fit the scale: · Hurricane Katrina, a category 3 at landfall SURGE 3 STORM SURGE: BEFORE AND AFTER Before Hurricane Katrina After Hurricane Katrina Images courtesyINTRODUCTION TO STORM SURGE Introduction to Storm Surge National Hurricane Center Storm Surge Unit

209

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

NASA Astrophysics Data System (ADS)

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

Deb, Mithun; Ferreira, Celso; Lawler, Seth

2014-05-01

210

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

NASA Technical Reports Server (NTRS)

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

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

2013-01-01

211

Storm Tracks Across Eastern Canada  

NASA Astrophysics Data System (ADS)

The global storm tracks patterns across the Northern Hemisphere are well documented, but their regional impact on populations has yet to be characterized, as very few studies took a local perspective on storm tracks. In this study, a Lagrangian tracking algorithm is applied to the 850 hPa relative vorticity field to characterize extratropical storm tracks that pass through major cities in Canada. Storm tracks are first classified in reference to the metropolitan cities that they impact, such as Toronto, Montreal, Halifax and St-John's. They are then subjected to several analyses, including but not limited to the identification of main development regions, typical tracks, mean growth rate, intensity and typical regions of decay. We found that the preferential development regions are the lee of the Rockies, the Great Lakes and the Western Atlantic. The collection of storm tracks across each city is composed of storms developing not from a single development region, but from several. Results show that the storm track variability at a city is dominated by the storm track variability of its predominant development region. Among others, we found that the ensembles of storms crossing East coast cities (Halifax, St-John's) are dominated by Atlantic storms that are most frequent during the winter. Storms passing through Montreal and Toronto travel primarily from the Great Lakes and the mid-latitude Rockies. In eastern Canada, storms from the southernmost part of the Rockies are much less frequent, but this development region is the main source of extreme storms, and is thus important in terms of impacts on metropolitan areas. The relationship between storm tracks and modes of atmospheric variability are also examined with an emphasis on the El Nino Southern Oscillation (ENSO) and Northern Annular Mode (NAM). We found that teleconnection shifts storm tracks differently in different development regions. The anomalous storm track densities are presented, as well as their direct impact on specific metropolitan areas. Results show that the combination of these shifts impact cities differently according to their geographic location.

Plante, Mathieu; Son, Seok-Woo; Gyakum, John; Kevin, Grise

2013-04-01

212

Use of the Aerosonde Unihabited Aerial Vehicle (UAV) in the Fourth Convection and Moisture Experiment (CAMEX 4)  

NASA Technical Reports Server (NTRS)

The Fourth Convection and Moisture Experiment (CAMEX 4) was a scientific field experiment based in Florida in summer 2001 focused on the study of hurricanes off the east coast of the United States. Sponsored by the National Aeronautics and Space Administration's Office of Earth Science, and conducted in collaboration with the National Oceanic and Atmospheric Administration's annual hurricane research program, CAMEX 4 utilized aircraft, ground-based and satellite instrumentation to obtain unprecedented, three dimensional characterizations of these important storms. The Aerosonde UAV was selected by NASA to participate in CAMEX 4 because it provided a unique capability to obtain measurements in the atmospheric boundary layer in and around the storms, unattainable by other platforms or measurement capabilities. This talk focuses on the NASA review process that was followed to coordinate the UAV activity with the conventional aircraft operations, as well as with the other participating agencies and the FAA. We will discuss how Aerosonde addressed the issues of safety, coordination and communication and summarize the lessons learned.

Hipskind, R. Stephen; Curry, Judy; Holland, Greg

2001-01-01

213

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.

214

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

215

Toward an integrated storm surge application: ESA Storm Surge project  

Microsoft Academic Search

Storm surges and their associated coastal inundation are major coastal marine hazards, both in tropical and extra-tropical areas. As sea level rises due to climate change, the impact of storm surges and associated extreme flooding may increase in low-lying countries and harbour cities. Of the 33 world cities predicted to have at least 8 million people by 2015, at least

Boram Lee; Craig Donlon; Olivier Arino

2010-01-01

216

Multisensor Investigation of Deep Convection  

NASA Astrophysics Data System (ADS)

The array of sensors for studying cloud systems from space provides the opportunity to globally map the occurrence of various types of deep convective cloud systems more precisely than ever before. The revolutionary TRMM satellite has not only determined rainfall from space but also identified the structures of storms producing the rainfall and how the different types of convective structures relate to features of the global circulation. The multiple sensors of the A-Train constellation have added more capacity to globally map convective cloud system types. By simultaneously using Aqua's MODIS 11-micron brightness temperature sensor to map cloud-top size and coldness, Aqua's AMSR-E passive microwave to detect rainfall, and CloudSat's cloud radar observations to see the internal structure of the nonprecipitating anvil clouds extending laterally from the precipitating cores of mesoscale convective systems (MCSs), we have objectively identified and mapped different types of MCSs. This multisensor analysis has determined the degrees to which MCSs vary according to size, amount of anvil cloud, and whether or not they occur separately or in merged complexes. Using these multisensor-derived quantities, we have established the patterns in which tropical MCSs occur over land, ocean, or the maritime continent. Ongoing work is integrating more sensors and other innovative global datasets into the analysis of A-Train data to further knowledge of MCSs and their variability over the Earth. Global lightning data are being integrated with the A-Train data to better understand convective intensity in different types of MCSs. Environments of the MCSs identified by multisensor A-Train analysis are being further analyzed using AIRS temperature profiles and MODIS and CALIPSO aerosol fields to better document the influence of environmental properties on the different types of mesoscale system. The integration of aerosol loading into the global analysis of the patterns of occurrence of deep convective system identified by multisensor analysis is especially important, as it will be the first truly global assessment of aerosol on the largest atmospheric convective systems. Although we are learning a lot about global patterns of deep MCSs from these multisensor studies, there remains a difficulty. Although the TRMM and A-Train satellite programs are both leading to exciting new information on the global patterns of deep convection and its organization into important mesoscale cloud entities, the knowledge gained from these two satellite programs is difficult to integrate in the quest for a more complete and holistic understanding of deep convection over the Earth. The A-Train data are showing in unprecedented detail aspects of the entire cloud system, and they have the powerful ability to separate the raining cores of the cloud systems from their nonprecipitating anvil clouds. However, the A-Train data lack three-dimensional details on the structure and type of convection. The TRMM radar on the other hand shows the detailed embedded structure of the precipitation cores but lacks information on the nonprecipitating cloud components. Future satellite programs should perhaps focus on how sensors detecting the precipitating components of deep convective cloud systems can be more simultaneously determining information from cloud radars and lidars that best show the nonprecipitating components of the cloud systems.

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

2012-12-01

217

A study of severe storm electricity via storm intercept  

NASA Technical Reports Server (NTRS)

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

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

1985-01-01

218

46 CFR 116.920 - Storm rails.  

Code of Federal Regulations, 2010 CFR

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2010-10-01

219

46 CFR 108.221 - Storm rails.  

Code of Federal Regulations, 2011 CFR

... 2011-10-01 2011-10-01 false Storm rails. 108.221 Section 108.221 Shipping ...DESIGN AND EQUIPMENT Construction and Arrangement Rails § 108.221 Storm rails. Each unit must have a storm rail in the...

2011-10-01

220

46 CFR 127.320 - Storm rails.  

Code of Federal Regulations, 2011 CFR

...2011-10-01 2011-10-01 false Storm rails. 127.320 Section 127.320 Shipping...SUPPLY VESSELS CONSTRUCTION AND ARRANGEMENTS Rails and Guards § 127.320 Storm rails. Suitable storm rails must be installed in...

2011-10-01

221

46 CFR 127.320 - Storm rails.  

Code of Federal Regulations, 2012 CFR

...2012-10-01 2012-10-01 false Storm rails. 127.320 Section 127.320 Shipping...SUPPLY VESSELS CONSTRUCTION AND ARRANGEMENTS Rails and Guards § 127.320 Storm rails. Suitable storm rails must be installed in...

2012-10-01

222

46 CFR 177.920 - Storm rails.  

Code of Federal Regulations, 2013 CFR

...2013-10-01 2013-10-01 false Storm rails. 177.920 Section 177.920 Shipping...GROSS TONS) CONSTRUCTION AND ARRANGEMENT Rails and Guards § 177.920 Storm rails. Suitable storm rails or hand grabs must...

2013-10-01

223

46 CFR 127.320 - Storm rails.  

Code of Federal Regulations, 2010 CFR

...2010-10-01 2010-10-01 false Storm rails. 127.320 Section 127.320 Shipping...SUPPLY VESSELS CONSTRUCTION AND ARRANGEMENTS Rails and Guards § 127.320 Storm rails. Suitable storm rails must be installed in...

2010-10-01

224

46 CFR 169.329 - Storm rails.  

Code of Federal Regulations, 2011 CFR

...2011-10-01 2011-10-01 false Storm rails. 169.329 Section 169.329 Shipping...SCHOOL VESSELS Construction and Arrangement Rails and Guards § 169.329 Storm rails. Suitable storm rails or hand grabs must...

2011-10-01

225

46 CFR 169.329 - Storm rails.  

Code of Federal Regulations, 2012 CFR

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2012-10-01

226

46 CFR 116.920 - Storm rails.  

Code of Federal Regulations, 2011 CFR

...2011-10-01 2011-10-01 false Storm rails. 116.920 Section 116.920 Shipping...49 PASSENGERS CONSTRUCTION AND ARRANGEMENT Rails and Guards § 116.920 Storm rails. Suitable storm rails or hand grabs must...

2011-10-01

227

46 CFR 116.920 - Storm rails.  

Code of Federal Regulations, 2012 CFR

...2012-10-01 2012-10-01 false Storm rails. 116.920 Section 116.920 Shipping...49 PASSENGERS CONSTRUCTION AND ARRANGEMENT Rails and Guards § 116.920 Storm rails. Suitable storm rails or hand grabs must...

2012-10-01

228

46 CFR 116.920 - Storm rails.  

Code of Federal Regulations, 2013 CFR

...2013-10-01 2013-10-01 false Storm rails. 116.920 Section 116.920 Shipping...49 PASSENGERS CONSTRUCTION AND ARRANGEMENT Rails and Guards § 116.920 Storm rails. Suitable storm rails or hand grabs must...

2013-10-01

229

46 CFR 177.920 - Storm rails.  

Code of Federal Regulations, 2012 CFR

...2012-10-01 2012-10-01 false Storm rails. 177.920 Section 177.920 Shipping...GROSS TONS) CONSTRUCTION AND ARRANGEMENT Rails and Guards § 177.920 Storm rails. Suitable storm rails or hand grabs must...

2012-10-01

230

46 CFR 177.920 - Storm rails.  

Code of Federal Regulations, 2010 CFR

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2010-10-01

231

46 CFR 108.221 - Storm rails.  

Code of Federal Regulations, 2012 CFR

... 2012-10-01 2012-10-01 false Storm rails. 108.221 Section 108.221 Shipping ...DESIGN AND EQUIPMENT Construction and Arrangement Rails § 108.221 Storm rails. Each unit must have a storm rail in the...

2012-10-01

232

46 CFR 169.329 - Storm rails.  

Code of Federal Regulations, 2013 CFR

...2013-10-01 2013-10-01 false Storm rails. 169.329 Section 169.329 Shipping...SCHOOL VESSELS Construction and Arrangement Rails and Guards § 169.329 Storm rails. Suitable storm rails or hand grabs must...

2013-10-01

233

46 CFR 169.329 - Storm rails.  

Code of Federal Regulations, 2010 CFR

...2010-10-01 2010-10-01 false Storm rails. 169.329 Section 169.329 Shipping...SCHOOL VESSELS Construction and Arrangement Rails and Guards § 169.329 Storm rails. Suitable storm rails or hand grabs must...

2010-10-01

234

46 CFR 177.920 - Storm rails.  

Code of Federal Regulations, 2014 CFR

...2014-10-01 2014-10-01 false Storm rails. 177.920 Section 177.920 Shipping...GROSS TONS) CONSTRUCTION AND ARRANGEMENT Rails and Guards § 177.920 Storm rails. Suitable storm rails or hand grabs must...

2014-10-01

235

46 CFR 169.329 - Storm rails.  

Code of Federal Regulations, 2014 CFR

...2014-10-01 2014-10-01 false Storm rails. 169.329 Section 169.329 Shipping...SCHOOL VESSELS Construction and Arrangement Rails and Guards § 169.329 Storm rails. Suitable storm rails or hand grabs must...

2014-10-01

236

46 CFR 108.221 - Storm rails.  

Code of Federal Regulations, 2014 CFR

... 2014-10-01 2014-10-01 false Storm rails. 108.221 Section 108.221 Shipping ...DESIGN AND EQUIPMENT Construction and Arrangement Rails § 108.221 Storm rails. Each unit must have a storm rail in the...

2014-10-01

237

46 CFR 108.221 - Storm rails.  

Code of Federal Regulations, 2013 CFR

... 2013-10-01 2013-10-01 false Storm rails. 108.221 Section 108.221 Shipping ...DESIGN AND EQUIPMENT Construction and Arrangement Rails § 108.221 Storm rails. Each unit must have a storm rail in the...

2013-10-01

238

46 CFR 116.920 - Storm rails.  

Code of Federal Regulations, 2014 CFR

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2014-10-01

239

46 CFR 127.320 - Storm rails.  

Code of Federal Regulations, 2013 CFR

...2013-10-01 2013-10-01 false Storm rails. 127.320 Section 127.320 Shipping...SUPPLY VESSELS CONSTRUCTION AND ARRANGEMENTS Rails and Guards § 127.320 Storm rails. Suitable storm rails must be installed in...

2013-10-01

240

46 CFR 177.920 - Storm rails.  

Code of Federal Regulations, 2011 CFR

...2011-10-01 2011-10-01 false Storm rails. 177.920 Section 177.920 Shipping...GROSS TONS) CONSTRUCTION AND ARRANGEMENT Rails and Guards § 177.920 Storm rails. Suitable storm rails or hand grabs must...

2011-10-01

241

46 CFR 127.320 - Storm rails.  

Code of Federal Regulations, 2014 CFR

...2014-10-01 2014-10-01 false Storm rails. 127.320 Section 127.320 Shipping...SUPPLY VESSELS CONSTRUCTION AND ARRANGEMENTS Rails and Guards § 127.320 Storm rails. Suitable storm rails must be installed in...

2014-10-01

242

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

243

Great magnetic storms revisited  

NASA Astrophysics Data System (ADS)

In this work we revisit a very important topic of space weather the great magnetic storms Our inspiration comes from the work done by Tsurutani et al GRL 1992 in which 5 Dst -250nT geomagnetic storms were studied in terms mainly of their interplanetary origin Since 1996 the post-SOHO era we have identified a number of 18 Dst -200nT events this time with a much more complete set of observations of the sun and of the near-earth space We use data from the Large Angle and Spectrometric Coronagraph and the Extreme Ultraviolet Imaging Telescope both aboard the Solar and Heliospheric Observatory to identify the solar origin of these events Solar wind and interplanetary magnetic field from the Advanced Composition Explorer are used to study these events in terms of their interplanetary structure We also address the high energy cosmic ray modulation caused by these events using ground-based muon observations from telescope installed at the Southern Space Observatory Brazil

Dal Lago, A.; Gonzalez, W. D.; Echer, E.; Vieira, L. E. A.; Guarnieri, F. L.; Clua de Gonzalez, A. L.; da Silva, M. R.; de Lucas, A.; Schuch, N. J.

244

Severe storm electricity  

NASA Technical Reports Server (NTRS)

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

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

1984-01-01

245

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

246

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

247

Ionospheric redistribution during geomagnetic storms  

NASA Astrophysics Data System (ADS)

The abundance of plasma in the daytime ionosphere is often seen to grow greatly during geomagnetic storms. Recent reports suggest that the magnitude of the plasma density enhancement depends on the UT of storm onset. This possibility is investigated over a 7year period using global maps of ionospheric total electron content (TEC) produced at the Jet Propulsion Laboratory. The analysis confirms that the American sector exhibits, on average, larger storm time enhancement in ionospheric plasma content, up to 50% in the afternoon middle-latitude region and 30% in the vicinity of the high-latitude auroral cusp, with largest effect in the Southern Hemisphere. We investigate whether this effect is related to the magnitude of the causative magnetic storms. Using the same advanced Dst index employed to sort the TEC maps into quiet and active (Dst<-100 nT) sets, we find variation in storm strength that corresponds closely to the TEC variation but follows it by 3-6h. For this and other reasons detailed in this report, we conclude that the UT-dependent peak in storm time TEC is likely not related to the magnitude of external storm time forcing but more likely attributable to phenomena such as the low magnetic field in the South American region. The large Dst variation suggests a possible system-level effect of the observed variation in ionospheric storm response on the measured strength of the terrestrial ring current, possibly connected through UT-dependent modulation of ion outflow.

Immel, T. J.; Mannucci, A. J.

2013-12-01

248

Thyroid storm: an updated review.  

PubMed

Thyroid storm, an endocrine emergency first described in 1926, remains a diagnostic and therapeutic challenge. No laboratory abnormalities are specific to thyroid storm, and the available scoring system is based on the clinical criteria. The exact mechanisms underlying the development of thyroid storm from uncomplicated hyperthyroidism are not well understood. A heightened response to thyroid hormone is often incriminated along with increased or abrupt availability of free hormones. Patients exhibit exaggerated signs and symptoms of hyperthyroidism and varying degrees of organ decompensation. Treatment should be initiated promptly targeting all steps of thyroid hormone formation, release, and action. Patients who fail medical therapy should be treated with therapeutic plasma exchange or thyroidectomy. The mortality of thyroid storm is currently reported at 10%. Patients who have survived thyroid storm should receive definite therapy for their underlying hyperthyroidism to avoid any recurrence of this potentially fatal condition. PMID:23920160

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

2015-03-01

249

Record-breaking Storm Activity on Uranus in 2014  

E-print Network

In spite of an expected decline in convective activity following the 2007 equinox of Uranus, eight sizable storms were detected on the planet with the near-infrared camera NIRC2, coupled to the adaptive optics system, on the 10-m W. M. Keck telescope on UT 5 and 6 August 2014. All storms were on Uranus's northern hemisphere, including the brightest storm ever seen in this planet at 2.2 $\\mu$m, reflecting 30% as much light as the rest of the planet at this wavelength. The storm was at a planetocentric latitude of $\\sim$15$^{\\circ}$N and reached altitudes of $\\sim$330 mbar, well above the regular uppermost cloud layer (methane-ice) in the atmosphere. A cloud feature at a latitude of 32$^{\\circ}$N, that was deeper in the atmosphere (near $\\sim$2 bar), was later seen by amateur astronomers. We also present images returned from our HST ToO program, that shows both of these cloud features. We further report the first detection of a long-awaited haze over the north polar region.

de Pater, Imke; Fry, P M; Hammel, Heidi B; Baranec, Christoph; Sayanagi, Kunio

2015-01-01

250

Mars Atmospheric Chemistry in Electrified Dust Devils and Storms  

NASA Technical Reports Server (NTRS)

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

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

2005-01-01

251

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

252

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.

Thorogood, Robert M. (Macungie, PA)

1983-01-01

253

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.

Thorogood, Robert M. (Macungie, PA)

1986-01-01

254

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

255

Summer Camp.  

ERIC Educational Resources Information Center

About 50 participants and 8 supervisors attended the Summer Camp. Visitors were encouraged and parents often came to see what their kids were doing. Before arriving at camp, the students learned how important balancing the supplies was when loading the boats. On the way to camp, students studied the: (1) landmarks so that they could find their way…

Pfisterer, Bill

256

Dust Storm in Syria  

NASA Technical Reports Server (NTRS)

MGS MOC Release No. MOC2-366, 20 May 2003

A dust storm rages in Syria Planum, south of the Labyrinthus Noctis troughs (at lower center) in this Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) composite of daily global images taken during the recent southern winter. In this view, water ice clouds are present over each of the five largest Tharsis volcanoes, Olympus Mons (right center), Alba Patera (upper center), Ascraeus Mons (near center), Pavonis Mons (toward lower left), and Arsia Mons (lower left). The summertime north polar residual water ice cap can be seen at the top of this picture. Sunlight illuminates the planet from the left.

2003-01-01

257

Storm on Saturn  

NASA Technical Reports Server (NTRS)

In September 1990, a white spot appeared on Saturn's atmosphere, which later spread over the entire equatorial region. The accompanying images were obtained as part of an effort to refine techniques for obtaining high resolution groundbased charge coupled device (CCD) images of the planets, and show the turbulent disturbance in Saturn's atmosphere. These broad red-band CCD images were obtained in November 1990 with the Catalina 1.5 m telescope. The planet was low in the sky at sunset, but the viewing was good enough to show detail in the equatorial region over all longitudes. Visibility of the features is enhanced by digital spatial filtering techniques. A storm of this magnitude has not been seen on Saturn since 1933.

Larson, Stephen M.

1991-01-01

258

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

NASA Technical Reports Server (NTRS)

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

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

2001-01-01

259

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

260

Dust Storms: Why Are Dust Storms a Concern  

MedlinePLUS

... Interactive Resources Careers in Environmental Health, Chemistry, and Toxicology More Resources What's New Site Map Dust Storms ... Developed by Specialized Information Services , Environmental Health and Toxicology Copyright Privacy Freedom of Information Act Accessibility Download ...

261

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

262

Centralized Storm Information System (CSIS)  

NASA Technical Reports Server (NTRS)

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

Norton, C. C.

1985-01-01

263

Overview of the Deep Convective Clouds and Chemistry Experiment  

NASA Astrophysics Data System (ADS)

The Deep Convective Clouds and Chemistry (DC3) project conducted a 7-week field campaign during May and June 2012 to study thunderstorm dynamical, physical, and electrical characteristics, as well as their effects on the atmosphere's composition, especially ozone and particles in the climate-sensitive upper troposphere near the thunderstorm tops. The NSF/NCAR Gulfstream V (GV) and the NASA DC-8 aircraft flew 17 coordinated flights to sample low-level inflow and upper troposphere outflow air near thunderstorms and to sample convective outflow air as it chemically aged during the next 24 hours. The DLR Falcon aircraft observed the fresh storm outflow and also obtained measurements of aged outflow. In total, 19 cases of active thunderstorms and over 6 cases of photochemical aging were flown. The DC3 aircraft, based in Salina, Kansas, were equipped with instruments to measure a variety of gases, aerosols, and cloud particle characteristics in situ as well as the NASA DC-8 measuring the ozone and aerosol distribution by lidar. The aircraft targeted storms predicted to occur within range of coverage by ground-based radar pairs, lightning mapping arrays (LMAs), and frequent launches of balloon-borne instruments that could measure the storm's physical, kinematic, and lightning characteristics. This coverage occurred in three regions: 1) northeastern Colorado, 2) central Oklahoma to western Texas, and 3) northern Alabama. DC3 demonstrated that it is possible to sample with two aircraft the inflow and outflow of storms, which were simultaneously sampled by the ground radars, LMAs, and soundings. The DC3 data set is extensive and rich. This presentation will summarize the overall statistics of the DC3 measurements giving a general idea of storm characteristics, transport of trace gases, and photochemical aging of species. Examples will be given of specific thunderstorm cases, including a Colorado case where a biomass-burning plume was ingested by a storm, and of sampling a thunderstorm, forecasting the location of the convective outflow plume the next day, and sampling the Day 2 convective outflow. In addition, the photochemical aging of convective outflow air from a decaying Mesoscale Convective System will be highlighted.

Barth, M. C.; Brune, W. H.; Cantrell, C. A.; Rutledge, S. A.; Crawford, J. H.; Flocke, F. M.; Huntrieser, H.

2012-12-01

264

Report Concerns: Storm Water Quality Hotline  

E-print Network

Report Concerns: Storm Water Quality Hotline: Please report any concerns, illegal dumping into storm drains, or suspi- cious activities that may cause environ- mental harm to the Storm Water Qual of Carolyn Lagattuta) UC SANTA CRUZ STORM WATER: Low Impact Development (LID) This brochure is created

California at Santa Cruz, University of

265

Report Concerns: Storm Water Quality Hotline  

E-print Network

Report Concerns: Storm Water Quality Hotline: Please report any concerns, illegal dump- ing into storm drains, or suspicious activi- ties that may cause environmental harm to the Storm Water Quality of Carolyn Lagattuta) UC SANTA CRUZ STORM WATER: Contractors, Outside Services & Lessees This brochure

California at Santa Cruz, University of

266

SUMMARY OF THREE INNOVATIVE STORM WATER BMPS  

Microsoft Academic Search

With the implementation of EPA's Phase 2 storm water permitting program and the changing focus of local and State storm water regulations, water quality and pollutant removal are growing issues in the storm water field. In this regulatory environment, municipal managers must look at storm water management in a holistic manner and determine such factors as the area to be

Tim Schmitt; Lauren Fillmore; Engineer Parsons; Jim Wheeler; Walid Hatoum

267

Summer Reading  

NSDL National Science Digital Library

Summer is a great time to kick back with a good book. Try The Bailey School Kids Series... it\\'s Great! Bailey School Kids Jan Brett is my favorite artist. It takes longer to look at the pictures than it does to read the book. But it\\'s worth it. Jan Brett I love Bunnicula, almost as much as I love Harold. Find out ...

Roner, Mrs.

2005-03-31

268

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

NASA Technical Reports Server (NTRS)

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

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

1984-01-01

269

Storm Precipitation in the United States. Part II: Soil Erosion Characteristics.  

NASA Astrophysics Data System (ADS)

Soil erosion is a major global challenge. An increased understanding of the mechanisms driving soil erosion, especially the storms that produce it, is vital to reducing the impact on agriculture and the environment. The objective of this work was to study the spatial distribution and time trends of the soil erosion characteristics of storms, including the maximum 30-min precipitation intensity (I30), storm kinetic energy of the falling precipitation (KE), and the storm erosivity index (EI) using a long-term 15-min precipitation database. This is the first time that such an extensive climatology of soil erosion characteristics of storms has been produced. The highest mean I30, KE, and EI values occurred in all seasons in the southeastern United States, while the lowest occurred predominantly in the interior west. The lowest mean I30, KE, and EI values typically occurred in winter, and the highest occurred in summer. The exception to this was along the West Coast where winter storms exhibited the largest mean KE and EI values. Linear regression was used to identify trends in mean storm erosion characteristics for nine U.S. zones over the 31-yr study period. The south-central United States showed increases for all three storm characteristics for all four seasons. On the other hand, higher elevations along the West Coast showed strong decreases in all three storm characteristics across all seasons. The primary agricultural region in the central United States showed significant increases in fall and winter mean EI when there is less vegetative cover. These results underscore the need to update the storm climatology that is related to soil erosion on a regular basis to reflect changes over time.

Angel, James R.; Palecki, Michael A.; Hollinger, Steven E.

2005-06-01

270

Magnetic Storms and Induction Hazards  

NASA Astrophysics Data System (ADS)

Magnetic storms are potentially hazardous to the activities and technological infrastructure of modern civilization. This reality was dramatically demonstrated during the great magnetic storm of March 1989, when surface geoelectric fields, produced by the interaction of the time-varying geomagnetic field with the Earth's electrically conducting interior, coupled onto the overlying Hydro-Québec electric power grid in Canada. Protective relays were tripped, the grid collapsed, and about 9 million people were temporarily left without electricity [Bolduc, 2002].

Love, Jeffrey J.; Joshua Rigler, E.; Pulkkinen, Antti; Balch, Christopher C.

2014-12-01

271

Hurricane and Severe Storm Lenticular  

NSDL National Science Digital Library

This resource is a 4 x 6" lenticular card on NASA's HS3 (Hurricane and Severe Storm Sentinel) aircraft mission, which will overfly tropical storms and hurricanes using NASA's Global Hawk Unmanned Aircraft Systems (UAS) in the Northern Atlantic, Caribbean, and Gulf of Mexico. These flights will improve our understanding of the processes that lead to the development of intense hurricanes. The mission will take place for one-month periods during the 2012, 2013, and 2014 Atlantic Basin hurricane seasons.

272

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

273

A simulation of the merger of convective clouds in the torrential rainfalls associated with the Meiyu front  

NASA Astrophysics Data System (ADS)

The merger of convective clouds in severe precipitation associated with the Meiyu front occurred near Nanjing during 4-5 July 2003 is investigated using satellite observational analyses and numerical simulations with the Weather Research and Forecast version 3.2. It is found that the merger of convective clouds plays a crucial role in the excessive storm. The severe rainfall event experiences a multi-scale organized process ranging from triggered convective bulbs, growing convective cells, to the formation of the convective complex. The development of convections causes the large-scale dynamic and thermodynamic environment change, which in turn favors the organized processes of convective systems and promotes multi-scale coupling of the nonlinear interaction between convections and its large-scale environment.

Ping, Fan; Luo, Zhexian; Tang, Xiba; Hu, Liang

2014-01-01

274

2014 Summer Housing Summer Housing dates  

E-print Network

2014 Summer Housing FACT SHEET Summer Housing dates: May 19, 2014 ­ August 9, 2014 "Rochester Shines in the Summer Time" Please read all of the information thoroughly. Once signed, your housing contract is binding. *We will begin accepting Summer Housing contracts Monday, April 7, 2014 GENERAL

Mahon, Bradford Z.

275

Characteristics of convective cells over the coastal regions of southeast Texas  

E-print Network

Vertical profiles of radar reflectivity and cloud-to-ground lightning characteristics associated with convective cells were analyzed for mesoscate systems occurring over the coastal regions of southeast Texas during the spring and summer months...

Robinson, Michael

1998-01-01

276

Storm over Dunes  

NASA Technical Reports Server (NTRS)

[figure removed for brevity, see original site]

Today's image shows a storm front moving across an area of the north pole populated with hundreds of small dark sand dunes. The north polar region contains large regions of sand dunes, perhaps providing the some of the material raised into these clouds.

Image information: VIS instrument. Latitude 75.7, Longitude 323.7 East (36.3 West). 40 meter/pixel resolution.

Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

2004-01-01

277

Dust storm of July 5th 2011, Phoenix, Arizona: Numerical simulation  

NASA Astrophysics Data System (ADS)

On July 5th 2011 Phoenix (Arizona) was hit with an intensive dust storm (haboob). The National Weather Service estimated the storm reached a peak height of at least 1500 to 1800 m, with a leading edge stretching nearly 100 miles (160 km). The storm traveled at least 240 km., reducing visibility in Phoenix to zero. At about 7 PM MST the dust storm hit the southeast corner of Phoenix and advanced through the entire city area during next two hours. The dust storm was generated by downburst winds associated with strong outflow wind passing over very dry areas with precipitation less than 50% of normal since the end of the 2010 summer. We will present a high-resolution model simulation of this dust storm using the NCEP/NMM non-hydrostatic atmospheric model with embedded DREAM (Dust Regional Weather Prediction Model). MODIS mcd12 data were used to derive dust source masks. Our experiments demonstrated the necessity of using high resolution of both dust sources and dust model in order to simulate this event accurately. In our experiments, the spatial and temporal features of the storm were accurately simulated achieving surface dust concentrations over 1000 ug/m3.

Vukovic, A. J.; Pejanovic, G.; Vujadinovic, M.; Sprigg, W. A.; Nickovic, S.; Djurdjevic, V.

2011-12-01

278

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

279

New opportunities for the study of Mediterranean storms: the unique capabilities of the Global Hawk aircraft  

NASA Astrophysics Data System (ADS)

Airborne measurements have often played a pivotal role in unravelling critical processess and improving our understanding of the genesis and development of atmospheric disturbances. The availability of innovative aerial platforms now opens new perspectives for the scientific research. One of these platforms is the high altitude long endurance unmanned aircraft Global Hawk (GH), which has unique capabilities in terms of altitude, range of operation, diurnal coverage and flexibility. The GH has an endurance of 31 hrs, a service ceiling of 20000 m and can host a payload of 680 kg. Since it can operate at altitudes close to the boundary conditions of radiative processes, can follow the diurnal variation of aerosol and clouds, can rapidly deploy new instruments with space-time coverage comparable to space-borne ones, it is a platform which is at the same time complementary and competitive with satellites. In fact it combines the short time deployment of aircraft instruments with the global coverage of satellite instruments, while its flight altitude allows better spatial resolution than a satellite and its endurance provides a sufficiently broad overview at a scale relevant for sinoptic meteorology studies. NASA has recently acquired two of such unmanned high altitude aircraft to address a variety of Earth Science objectives, and Italy has a decade long experience of stratospheric in-situ and remote sensing science missions using the Russian M-55 "Geophysica" high altitude piloted aircraft. There is a common interest in a bilateral cooperative program in climate change science using the GH. The collaboration between NASA and Italian scientific institutions may offer the opportunity of deploying the GH over the Mediterranean Basin. The Mediterranean area is of particular interest under many respects. As instance, it would be of great interest to measure, when possible, the 3-dimensional structure and evolution of the aerosol content over the Mediterranean, with particular emphasis on Saharan Air Layer (SAL) events. The frequent occurrence of such events, influencing the development of heavy precipitation systems in the region, as they do for hurricane genesis in the Atlantic west of Africa, promts the study of their impact on microphysical processes during precipitation formation; on lower and upper atmosphere destabilization stemming respectively from the production of a deep mixed layer of near zero potential vorticity and from the associated capping warm layer; and on their radiative impact leading to an enhanced heating of the lower troposphere due to solar radiation absorption by the Saharan dust itself. A different area of investigation would be the study of origin and fate of strong mesoscale disturbances originating in the area during the end of Summer and Fall period. In fact, while most Mediterranean storms have classic baroclinic origins, there are intense mesoscale convective storms which form and evolve into warm core structures deriving their energy directly from the warm sea surface in a fashion similar to tropical cyclones, e.g. hurricanes and typhoons. This type of tropical-like storms have been named Medicanes: understanding their origin and development is of utmost importance in view of their potential changing response in relationship to expected climate changes since it has been speculated that these Mediterranean storms would become more frequent and more vigorous in the near future due to the Mediterranean sea-surface temperature increase that is (probably) already occurring because of global warming. Remote sensing instrumentation (radars, microwave radiometers, lidars) is a primary tool to address this issue from a high-flying platform, to improve the understanding of the thermodynamics, dynamics, and microphysics of clouds, by measuring the evolution of their 3-dimensional thermodynamical, dynamical, and microphysical structures and the 3-dimensional structure and evolution of the aerosol content. The long endurance of the GH will allow the study of cloud systems following their evolution ov

Cairo, F.; Curry, R. E.; Carli, B.

2009-09-01

280

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.

281

Summer Studies CALENDAR 2010  

E-print Network

Summer Studies UNIVERSITY CALENDAR 2010 #12;McGill University, 2010 Summer Studies 1 ABOUT About This Calendar Published by: McGill Summer Studies McGill University 688 Sherbrooke Street West, Suite 1029, and changes can be made after this Calendar is published. Please check the Summer Studies website at www.mcgill.ca/summer

Fabry, Frederic

282

Munich International Summer University  

E-print Network

1 Munich International Summer University Summer 2012 #12;#12;MISU® ANNUAL REPORT 2012 #12. Finally, five years ago, the Munich International Summer University, or MISU®, was established. That meant´s summer courses were integrated into the Munich International Summer University, or MISU®, giving

Kersting, Roland

283

Meteorological aspects associated with dust storms in the Sistan region, southeastern Iran  

NASA Astrophysics Data System (ADS)

Dust storms are considered natural hazards that seriously affect atmospheric conditions, ecosystems and human health. A key requirement for investigating the dust life cycle is the analysis of the meteorological (synoptic and dynamic) processes that control dust emission, uplift and transport. The present work focuses on examining the synoptic and dynamic meteorological conditions associated with dust-storms in the Sistan region, southeastern Iran during the summer season (June-September) of the years 2001-2012. The dust-storm days (total number of 356) are related to visibility records below 1 km at Zabol meteorological station, located near to the dust source. RegCM4 model simulations indicate that the intense northern Levar wind, the high surface heating and the valley-like characteristics of the region strongly affect the meteorological dynamics and the formation of a low-level jet that are strongly linked with dust exposures. The intra-annual evolution of the dust storms does not seem to be significantly associated with El-Nino Southern Oscillation, despite the fact that most of the dust-storms are related to positive values of Oceanic Nino Index. National Center for Environmental Prediction/National Center for Atmospheric Research reanalysis suggests that the dust storms are associated with low sea-level pressure conditions over the whole south Asia, while at 700 hPa level a trough of low geopotential heights over India along with a ridge over Arabia and central Iran is the common scenario. A significant finding is that the dust storms over Sistan are found to be associated with a pronounced increase of the anticyclone over the Caspian Sea, enhancing the west-to-east pressure gradient and, therefore, the blowing of Levar. Infrared Difference Dust Index values highlight the intensity of the Sistan dust storms, while the SPRINTARS model simulates the dust loading and concentration reasonably well, since the dust storms are usually associated with peaks in model simulations.

Kaskaoutis, D. G.; Rashki, A.; Houssos, E. E.; Mofidi, A.; Goto, D.; Bartzokas, A.; Francois, P.; Legrand, M.

2014-06-01

284

A kinetic energy study of the meso beta-scale storm environment during AVE-SESAME 5 (20-21 May 1979)  

NASA Technical Reports Server (NTRS)

Kinetic energy of the near storm environment was analyzed by meso beta scale data. It was found that horizontal winds in the 400 to 150 mb layer strengthen rapidly north of the developing convection. Peak values then decrease such that the maximum disappears 6 h later. Southeast of the storms, wind speeds above 300 mb decrease nearly 50% during the 3 h period of most intense thunderstorm activity. When the convection dissipates, wind patterns return to prestorm conditions. The mesoscale storm environment of AVE-SESAME 5 is characterized by large values of cross contour generation of kinetic energy, transfers of energy to nonresolvable scales of motion, and horizontal flux divergence. These processes are maximized within the upper troposphere and are greatest during times of strongest convection. It is shown that patterns agree with observed weather features. The southeast area of the network is examined to determine causes for vertical wind variations.

Printy, M. F.; Fuelberg, H. E.

1984-01-01

285

Areal coverage of storm precipitation  

NASA Technical Reports Server (NTRS)

The probability distributions of the spatial distribution of precipitation from storms of different types were studied. The occurrence of wetted rainstorm area within a catchment was modeled as a Poisson arrival process in which each storm is composed of stationary, nonoverlapping, independent random cell clusters whose centers are Poisson-distributed as through fractals. The portion of a catchment covered by a stationary rainstorm was modeled by the common area of two overlapping circles. The first two moments of the distribution of the common area were derived from purely geometrical considerations. The spatial structure of the depth of rainfall from a stationary rainstorm was investigated using point process techniques. Total storm rainfall at the center of each cell is a random variable, and rainfall is distributed around the center specified by a spread function that may incorporate random parameters.

Eagleson, P. S.

1985-01-01

286

Ram Orientation Summer 2014  

E-print Network

Ram Orientation Guide Summer 2014 #12;Page 2 Table of Contents Welcome to welcome you to the University Honors Program (UHP) community and the summer Ram Orientation experience Program Administrative Director Coordinator Coordinator Coordinator Assistant Summer 2014 #12;Page 4

287

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

NASA Astrophysics Data System (ADS)

The occurrence, timing, and location of deep, moist convection remains a problem for operational weather forecasting, despite the rapid development of the numerical weather prediction models and implementation of new observational techniques. One impediment to better forecasting of deep convection is the role played by tropopause folds. How deep convection is modulated by tropopause folding, which brings stratospheric air into the troposphere, is not well understood. Three ingredients are required for deep moist, convection- moisture, instability, and lift-and all three ingredients associated with tropopause folds can either promote or suppress convection. For example, the dry air associated with the descent of upper-tropospheric air may limit the vertical development of buoyant thermals, yet this dry air may also create potential instability. The purpose of the research project TROSIAD is to assess the importance for convection forecasting of correctly representing tropopause folds in numerical weather forecasting models and to disentangle the conflicting paradigms that tropopause folds both promote and suppress convection. The work plan of the project involves the analysis of existing data from the Mesosphere-Stratosphere-Troposphere (MST) Radar at Aberystwyth, UK, which can measure both tropopause folds and convection, a number of cases studies from measurement campaigns, and numerical modelling experiments. The project begins with building 5-year (2006-2010) climatologies of radar data, and wind-profiling data to determine the relationship between tropopause folds and deep moist convection. Using data from Met Office NIMROD radar network, a climatology of all convective storms with the track in study region was developed. To be included in the climatology, a convective storm must persist for at least 30 minutes with a maximum radar reflectivity greater than 30 dBZ. A total of 663 convective storms were identified. A climatology of the tropopause folds over Wales was developed based on the MST radar data. Tropopause folds can be identified in the wind speed plots, coinciding with maxima in wind shear and echo power. A total of 231 tropopause folds events were identified. By combining the severe-storm and tropopause-fold climatologies 76 convective storms were associated with tropopause folds. About half of these cases (42%) were observed on the western side of an upper level trough, a region in which the convection is in generally considered as being suppressed. As an exemplification of entangled effects of tropopause folds on convection, two case studies are presented. The first event took place on 24 May 2006, when a cold front has passed over the UK, and convection was associated with moist air moving north-eastward over Wales, and becoming instable when the tropopause due to the presence of dry air in the tropopause fold above. In the second case on 2 December 2006, again associated with the passage of a cold front, the tropopause fold reached a lower attitude in comparison with the first case, suppressing convection. We also studied the morphology of the storms associated with tropopause folds, and we found that 51% of the cases are associated with multicellular convective lines, 25% are isolated cells, and 24% are multicellular clusters.

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

2012-04-01

288

Severe Convection II: Mesoscale Convective Systems  

NSDL National Science Digital Library

Mesoscale convective systems occur worldwide and year-round and are accompanied by the potential for severe weather and flooding. This module describes typical system evolution by examining squall line, bow echo, and MCC characteristics throughout their life cycles. This module has less emphasis on the physical processes controlling MCS structure and evolution than our previously released module, Mesoscale Convective Systems: Squall Lines and Bow Echoes. Instead, this newly updated module includes more material on tropical squall lines, MCC's, and on NWPâs ability to predict convective systems. The module starts with a forecast scenario and concludes with a final exam. Rich graphics, audio narration, and frequent interactions enhance the learning experience.

Comet

2004-09-24

289

A coordinated study of a storm system over the South American continent. I. Weather information and quasi-dc stratospheric electric field data  

SciTech Connect

A coordinated campaign conducted in Brazil on 13 December 1989, to study the electrical signals associated with a large storm system over the South American continent is presented. Within the storm, large convective cells developed extending up to the tropopause, as observed from meteorological balloon soundings. The analysis of IR imagery supports the general tendency for lightning strikes to be close to but not exactly beneath the coldest cloud tops. 35 refs.

Pinto, O. Jr.; Pinto, I.R.C.A.; Gin, R.B.B.; Mendes, O. Jr. (INPE, Sao Jose dos Campos (Brazil))

1992-11-01

290

Auroral currents during the magnetic storm of November 8 and 9, 1991 - Observations from the Upper Atmosphere Research Satellite Particle Environment Monitor  

NASA Technical Reports Server (NTRS)

The development of the intensity and location of Birkeland currents associated with the magnetic storm of November 8-9, 1991 is reported. Total Birkeland currents exceed 30 MA, more than six times nominal values, indicating Joule heating of about 3 x lO exp 12 W. Birkeland currents below 50 deg, polar cap currents indicative of antisunward convection, and cusp particle signatures of southward IMF all persist at least eight hours into recovery phase of the storm.

Anderson, B. J.; Potemra, T. A.; Bythrow, P. F.; Zanetti, L. J.; Holland, D. B.; Winningham, J. D.

1993-01-01

291

A summary of research on mesoscale energetics of severe storm environments  

NASA Technical Reports Server (NTRS)

The goals of this research were to better understand interactions between areas of intense convection and their surrounding mesoscale environments by using diagnostic budgets of kinetic (KE) and available potential energy (APE). Three cases of intense convection were examined in detail. 1) Atmospheric Variability Experiments (AVE) carried out on 24 to 25 April 1975 were studied. Synoptic scale data at 3 to 6 hour intervals, contained two mesoscale convective complexes (MCCs). Analyses included total KE budgets and budgets of divergent and rotational components of KE. 2) AVE-Severe Environmental Storms and Mesoscale Experiments (SESAME)-4 carried out on 10 to 11 April 1979 were studied. Synotpic and meso alpha-scale data (250 km spacing, 3 hour intervals), contained the Red River Valley tornado outbreak. Analyses included total KE budgets (separate synoptic and mesoscale version), budgets for the divergent and rotational components, and the generation of APE by diabatic processes. 3) AVE-SESAME 5 studies were carried out on 20 to 31 May 1979. Synoptic and meso beta-scale data (75 km spacing, 1 1/2 to 3 hour intervals), contained a small MCC. Analyses include separate KE budgets for the synotic and meso beta-scales and a water vapor budget. Major findings of these investigations are: (1) The synoptic scale storm environment contains energy conversions and transports that are comparable to those of mature midlatitude cyclones. (2) Energetic in the mesoscale storm environment are often an order of magnitude larger than those in an undisturbed region. (3) Mesoscale wind maxima form in the upper troposphere on the poleward sides of convective areas, whereas speeds decrease south of storm regions.

Fuelberg, H. E.

1985-01-01

292

RECOVERY OF MONTEREY BAY BEACHES AFTER THE WINTER STORMS OF 1982-83.  

USGS Publications Warehouse

The El Nino conditions of 1982 and 1983 produced unusually frequent and intense storms along the central California coast. These storms produced much greater than normal beach erosion in Monterey Bay, causing extensive damage to coastal structures, erosion of coastal cliffs, and loss of sand from coastal dunes. The beaches accreted during the summer of 1983 and eroded again the next winter. Every beach, however, showed its own pattern of rebuilding; the eigenfunction analysis showed that the beaches did not all reach either their maximum or minimum volumes at the same time.

Dingler, John R.; Anima, Roberto J.; Clifton, H. Edward

1985-01-01

293

Is Titan's dune orientation controlled by tropical methane storms?  

NASA Astrophysics Data System (ADS)

Titan's equatorial regions are covered by eastward oriented linear dunes. This direction is opposite to mean surface winds simulated by Global Climate Models (GCMs) at these latitudes, oriented westward as trade winds on Earth [1, 2]. Here, we propose that Titan's dune orientation is actually determined by equinoctial tropical methane storms. Using meso-scale simulations of convective methane clouds [3, 4] with a GCM wind profile featuring the super-rotation [5, 6], we show that Titan's storms should produce fast eastward gust fronts above the surface (see Figure 1). Such gusts dominate the aeolian transport. Using GCM wind roses and analogies with terrestrial dune fields as the Rub' al-Khali desert, we show that under these conditions Titan's dune growth occurs eastward (see Figure 2). Moreover, we explain other features of Titan's dunes (i.e. divergence from the equator, size and spacing). This analysis therefore reveals an unexpected coupling between super-rotation, tropical storms and dune formation on Titan, and has implications for the understanding of terrestrial dunes. References: [1] Lorenz et al. (2006) Science [2] Lorenz & Radebaugh (2009) Geophysical Research Letter [3] Barth & Rafkin (2007) Geophysical Research Letter [4] Barth & Rafkin (2010) Icarus [5] Charnay & Lebonnois (2012) Nature Geoscience [6] Lebonnois et al. (2012) Icarus Development of a methane storm with formation of a gust front. Colorbar corresponds to the mixing ratio of condensed methane (in g/kg) Resultant drift direction obtained by combining the GCM sand flux roses with the impact of one gust front every equinox at any location.

Charnay, B.; Barth, E. L.; Rafkin, S. C.; Narteau, C.; Lebonnois, S.; Rodriguez, S.

2013-12-01

294

Estimation of convective mass transfer in solar distillation systems  

Microsoft Academic Search

In this article a thermal model has been developed to determine the convective mass transfer for different Grashof Number range in solar distillatiOn process. The model is based on simple regression analysis. Based on the experimental data obtained from the rigorous outdoor experimentation on passive and active distillation systems for summer climatic conditions, the values of C and n have

Sanjay Kumar; G. N. Tiwari

1996-01-01

295

Electron acceleration in solar noise storms  

E-print Network

We present an up-to-date review of the physics of electron acceleration in solar noi se storms. We describe the observed characteristics of noise storm emission, emphasi zing recent advances in imaging observations. We briefly describe the general method ology of treating particle acceleration problems and apply it to the specific proble m of electron acceleration in noise storms. We dwell on the issue of the efficiency of the overall noise storm emission process and outline open problems in this area.

Prasad Subramanian

2007-01-23

296

Storm Effects on Net Ecosystem Productivity in Boreal Forests  

NASA Astrophysics Data System (ADS)

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 storm Gudrun hit Sweden, which resulted in approx. 66 × 106m3storm-felled stem wood distributed over an area of approx. 272 000 ha. Eddy covariance flux measurements started at storm-felled areas in Asa and Toftaholm in central Sweden during summer 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.

Vestin, Patrik; Grelle, Achim; Lagergren, Fredrik; Hellström, Margareta; Langvall, Ola; Lindroth, Anders

2010-05-01

297

The effects and characteristics of atmospheric dust during martian global dust storm 2001A  

NASA Astrophysics Data System (ADS)

We present retrieved trends in dust optical depth, dust effective radius and surface temperature from our analysis of Mars Global Surveyor Thermal Emission Spectrometer daytime data from global dust storm 2001A, and describe their significance for the martian dust cycle. The dust optical depth becomes correlated with surface pressure during southern spring and summer in years both with and without a global dust storm, indicating that global dust mixing processes are important at those seasons. The correlation is low at other times of the year. We found that the observed decay of optical depths at the later stages of the dust storm match, to first-order, theoretical values of clearing from Stokes-Cunningham fallout of the dust. Zonally averaged effective radius is constant within standard deviation of results (between 1.2 and 2.0 ?m, with a global mean for all seasons of 1.7 ?m), at all latitudes and seasons except at southern latitudes of 35° and higher around equinoxes in both martian years, where it is larger than average (2-3 ?m). The emergence and disappearance of these larger particles correlates with observations of polar cap edge storms at those latitudes. Northern latitude observations under similar conditions did not yield a similar trend of larger average effective radii during the equinoxes. We also report on a linear correlation between daytime surface temperature drop and rise in optical depth during the global dust storm. Global dust storm 2001A produced a significant optical depth and surface temperature change.

Elteto, Attila; Toon, Owen B.

2010-12-01

298

Tropical Storm Allison Progression (WMS)  

NSDL National Science Digital Library

Tropical Storm Allison began just five days into the 2001 hurricane season. Allison formed in the warm waters of the Gulf of Mexico, and dumped an enormous amount of rain on Texas, Louisiana, Florida, and other states in the southeastern United States.

Sokolowsky, Eric; Perkins, Lori; Kuring, Norman; Feldman, Gene

2004-03-11

299

Observing auroral storms on Saturn  

NASA Astrophysics Data System (ADS)

Saturn's poles, like the Earth's, experience auroral storms when solar wind—streams of high-energy plasma—interacts with its magnetosphere. By using instruments aboard spacecraft, scientists have been able to study Saturn's auroras but are still far from understanding them completely.

Wendel, JoAnna

2014-11-01

300

Space storms as natural hazards  

Microsoft Academic Search

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 storms can potentially destroy spacecrafts, adversely affect astronauts and airline crew and human health on the Earth, lead to pipeline breaking, melt electricity transformers, and

L. I. Dorman; N. G. Ptitsyna; G. Villoresi; V. V. Kasinsky; N. N. Lyakhov; M. I. Tyasto

2008-01-01

301

Winter Storms For More Information  

E-print Network

-related brochures. You can find more information on flash flooding in the Floods... The Awesome Power brochure site http://www.nws.noaa.gov/om/water/ahps/ pdfs/Floodsbrochure_02_06.pdf. To find additional materials of these threats. · A major winter storm can last for several days and be accompanied by high winds, freezing rain

302

Extreme convection of the near-equatorial Americas, Africa, and adjoining oceans as seen by TRMM  

E-print Network

), and broad stratiform regions (BSR). ECMWF Interim reanalysis data show the associated synoptic environmental factors associated with the occurrence of extreme convective features. The DCC, WCC, and BSR echoes of easterly waves. Storms containing BSR maximize over oceanic regions west of Africa and South America, where

Houze Jr., Robert A.

303

Forecasting Convective Downburst Potential Using GOES Sounder Derived Products Ken Pryor (NOAA/NESDIS/ORA/STAR)  

E-print Network

downdraft produced by a convective storm (i.e., thunderstorm) that induces an outward burst of damaging they produce, downbursts are a hazard to aircraft in flight, especially during takeoff and landing phases. #12/NESDIS/ORA/STAR) GOES Microburst Products · GOES sounder-derived parameters have been shown to be useful in assessing

Kuligowski, Bob

304

Characteristics of Precipitating Convective Systems in the Premonsoon Season of South Asia  

E-print Network

. 2008; Yamane and Hayashi 2006). The storms are sometimes extremely deep and intense (Hirose and Nakamura 2002; Islam and Uyeda 2008; Romatschke et al. 2010), with a maximum in lightning activity (Lal. Romatschke et al. (2010) compared extreme convection in the premonsoon and monsoon, and Laing and Fritsch

Houze Jr., Robert A.

305

The summer NAO and northwest European climate  

NASA Astrophysics Data System (ADS)

The summer North Atlantic Oscillation (SNAO) was recently defined for northern hemisphere high summer (July-August) as the leading EOF in sea level pressure for the North Atlantic/Europe region. It consists of a pressure dipole with nodes over Greenland and the UK/Scandinavia. By analogy with the winter NAO, SNAO is characterized by a more northerly location and smaller spatial scale than its winter counterpart. It is believed to exert a strong influence on Northwest European climate through changes in the position of the North Atlantic storm track, and the influence needs to be quantitively addressed with considerable accuracy. The association betweens the mean sea level pressure (MSLP) in European-North Atlantic region in high summer and simultaneous land surface temperature and precipitation are studies with a coupled manifold technique and SVD analysis. We find that summer climate in northwest Europe is strongly influence by SNAO. Considering European land, we estimate that 45% (27%) of the summer temperature (precipitation) variance is forced MSLP; while in northwest Europe, the variance of temperature (precipitation) forced by MSLP is around 65% (32%). The positive phase of SNAO forces a positive temperature anomaly in northwest Europe centering Baltic Sea, and a very weak negative anomaly in southeast Europe. A similar precipitation pattern was forced by SNAO, while the negative phase forced by positive SNAO is much larger and extended to west Mediterranean.

Wang, G.; Dolman, A. J.

2009-04-01

306

The Tropical Convective Spectrum. Part 1; Archetypal Vertical Structures  

NASA Technical Reports Server (NTRS)

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

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

2005-01-01

307

Vertical structure of Saturn lightning storms and storm-related dark ovals  

NASA Astrophysics Data System (ADS)

In Cassini ISS images of Saturn during 2004-2006 Dyudina et al. (2007, Icarus 190, 545-555) identified four cases in which bright cloud features near 35o S were correlated with thunderstorm activity, inferred from SED events detected by the Radio and Plasma Wave Science instrument. The bright features left behind remnant dark ovals that reached full contrast within about a week. Baines et al. (2009, Plan. & Space Sci. 57, 1650-1658) investigated similar radio-correlated storms, using 2008 VIMS spectra. Noting that the dark ovals were about 20% less reflective than surrounding clouds over a wide spectral range, they suggested that the cloud particles might contain a broadband absorber that was produced by lightning-induced chemistry at the 10-20 bar water cloud level and convected up to the visible cloud level. Another possibility is that lower optical depths cause the ovals to be less reflective than the surrounding clouds. We carried out quantitative radiative transfer calculations to evaluate these alternatives, and also derived cloud models for the active region that is the presumed source of lightning. The main result for the dark ovals is that we can obtain good fits with typical condensates in vertically thin cloud layers, but can also obtain good fits with deep clouds of composite particles containing a sooty core within a shell of n=1.4+0i material. However, unlike Saturn's Great Storm of 2010-2011 (Sromovsky et al. 2013, Icarus), neither the bright clouds nor the dark ovals show the significant 3-micron absorption that would be expected if NH3, NH4SH, or H20 were lofted to upper cloud level. This missing absorption tends to favor models in which the upper cloud layer (near 250 mbar) is comprised of conservative (non-absorbing) particles and physically thin, in which case the dark oval spectra can be explained by a reduced upper cloud opacity (by ~50%) relative to surrounding clouds, and raises the possibility that the upper cloud features might be generated by waves rather than by convection all the way up to the visible cloud level.This research was supported by grant NNX11AM58G from NASA's Outer Planets Research Program.

Sromovsky, Lawrence A.; Baines, Kevin H.; Fry, Patrick M.

2014-11-01

308

Martian global dust storm 2001A as observed by the Mars Global Surveyor Thermal Emission Spectrometer  

NASA Astrophysics Data System (ADS)

The purpose of this work is to study the general characteristics of Martian global dust storms, and their relation to the Martian dust cycle using infrared observations. I devised a parameter retrieval algorithm for Mars Global Surveyor Thermal Emission Spectrometer daytime data from global dust storm 2001A that extracts information about dust optical depth, effective radius, and surface temperature using Newtonian first-order sensitivity functions of the infrared spectrum in response to variations in these parameters. This algorithm is both relatively accurate and very fast, successfully retrieving parameters from 56878 spectra for global dust storm 2001A, as well as a subsequent Martian year in comparison. There are uncertainties introduced into the retrievals, especially by parameters that could not be constrained such as the optical constants of the Martian dust. Uncertainties in assumed vertical mixing of dust can lead to significant uncertainties in retrieved optical depth and dust effective radius. I discovered several aspects of the dust storm that have not previously been recognized. One of these is that the dust optical depth becomes correlated with surface pressure during the decay phase of the dust storm. Similar pressure optical depth correlations were found the following Martian year when no global dust storm occurred. Global correlation of dust optical depth and surface pressure, indicative of global dust mixing processes, also varies with the season. It is generally larger during southern hemisphere late spring and summer, and very low at all other seasons when there is no global dust storm. These pressure and optical depth data provide a tool to study atmospheric dynamics. I also found that the observed decay of optical depths at the later stages of the dust storm match, to first order, theoretical values of clearing from Stokes-Cunningham fallout of the dust. The unprecedented coverage of the retrieval of dust effective radii allowed me to discover previously unseen global trends. Zonally averaged effective radius is constant, within uncertainties, at all latitudes and seasons except at high southern latitudes around equinoxes in both Martian years, where it is larger than average. The emergence and disappearance of these larger particles correlates with observations of polar cap edge storms at those latitudes. Northern latitude observations under similar conditions yielded systematically lower average effective radii. I also discovered a previously unreported linear correlation between daytime surface temperature drop and rise in optical depth during the global dust storm. Global dust storm 2001A produced a significant optical depth and surface temperature anomaly in the dust cycle that was responsible for abating local dust storms. The observations of trends in effective radii are significantly different from trends predicted by global circulation models and need to be accounted for in future studies.

Elteto, Attila

2009-06-01

309

Mechanisms initiating deep convection over complex terrain during COPS.  

SciTech Connect

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

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

2008-12-01

310

Effects of urban pollution on downwind storms: An energetic perspective  

NASA Astrophysics Data System (ADS)

In two previous studies. the effects of the Houston Metropolitan area on the characteristics and intensity of convection 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 convective cells due to additional latent heat release. However, results showed an interesting non-monotonic behavior of convection 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 convective 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 storm 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 convective 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 convective cells, and indicate that the expected increase of the particulate pollution is more likely to selectively enhance precipitation of convective events characterized by higher instability and extreme precipitation events.

Carrio, G. G.

2011-12-01

311

Large Geomagnetic Storms: Introduction to Special Section  

NASA Technical Reports Server (NTRS)

Solar cycle 23 witnessed the accumulation of rich data sets that reveal various aspects of geomagnetic storms in unprecedented detail both at the Sun where the storm causing disturbances originate and in geospace where the effects of the storms are directly felt. During two recent coordinated data analysis workshops (CDAWs) the large geomagnetic storms (Dst < or = -100 nT) of solar cycle 23 were studied in order to understand their solar, interplanetary, and geospace connections. This special section grew out of these CDAWs with additional contributions relevant to these storms. Here I provide a brief summary of the results presented in the special section.

Gopalswamy, N.

2010-01-01

312

Magnetospheric Convection near a Drainage Plume  

NASA Astrophysics Data System (ADS)

We report on equatorial convection associated with a plasmaspheric drainage plume using simultaneous observations from five satellites. During the early recovery phase of the July 2000 Bastille Day magnetic storm, the Extreme Ultraviolet sensor on the Magnetopause-to-Aurora Global Exploration satellite detected the plume near 16:00-17:00 magnetic local time extending outward to L ? 2.8. The plasmaspheric boundary was near L = 2 at other local times. We mapped simultaneously measured ionospheric plasma drifts from ROCSAT-1 and three Defense Meteorological Satellite Program (DMSP) spacecraft along magnetic field lines to infer equatorial convection velocities in the inner magnetosphere. The zonal component of convection derived from ROCSAT-1 ion-drift measurements had a sharp, positive azimuthal gradient near the plume's boundaries, reversing direction from westward to eastward. The meridional profile of horizontal velocities deduced from DMSP measurements shows a large, westward-flowing subauroral polarization stream (SAPS) located outside the plasmapause. The peak velocity of the SAPS centered at a radial distance of L ? 2.8 with a full width of ˜1 RE. In the inertial frame of reference, equatorial plasmas flowed toward the plume from both its day and evening sides, suggesting a negative gradient in the equatorial azimuthal velocity that was largest near the plume's outermost boundary. These observations provide new evidence about diversion of SAPS plasma flows and distinctive azimuthal velocity patterns in the vicinity of plasmaspheric plumes.

Lin, Chin S.; Yeh, Huey-Ching; Sandel, Bill R.; Goldstein, J.; Rich, Frederick J.; Burke, William J.; Foster, J. C.

2007-05-01

313

Summer Study Columbia College  

E-print Network

Summer Study Columbia College How many points may I take through Columbia's Summer Session? Columbia students may take no more than eight points in any Columbia Summer Session period or in overlapping periods, and a maximum of sixteen points for the entire summer. May I take any class during

Hone, James

314

Summer University PRAGUE 2012  

E-print Network

Summer University PRAGUE 2012 Topic: "East goes west ­ West goes east?" Searching for a new: September 8th ­ September 23rd 2012 (16 days) Place: Prague, Czech Republic Program: http://summer) Application: on-line http://summer-university.fsv.cuni.cz Contact: E-mail: summer

Wu, Yih-Min

315

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

316

Munich International Summer University  

E-print Network

Munich International Summer University Summer 2011 #12;MISU® ANNUAL REPORT 2011 #12;#12;MISU- nich International Summer University. MISU® is an excellent opportunity for international students International Summer University, or MISU®, giving a distinct vision and common standards to the various programs

Gerkmann, Ralf

317

Summer Research Student Handbook  

E-print Network

in the program during the summer. Interns are matched with mentors in laboratories or clinics at TulaneSummer Research Internship Student Handbook 2012 #12;Congratulations Summer Research Internship Participants! Welcome to the 2012 Summer Research Internship Program. We are thrilled to have you join us

318

international summer school 2012  

E-print Network

international summer school 2012 studenthandbook #12;international summer school 2012 Class of 2012 international summer school 2012 Welcome to the University of Exeter We are delighted that you have won a place on the International summer school for 2012. studenthandbook We are proud of our position as a top 10 university

Mumby, Peter J.

319

Summer 2012 Class ScheduleSummer 2012 Class Schedule Summer . . . focused . . . flexible . . . friendly!  

E-print Network

1 Summer 2012 Class ScheduleSummer 2012 Class Schedule Summer . . . focused . . . flexible . . . friendly! #12;Welcome to Summer Session at Colorado State University! For Non-CSU Students: Easy On-Line Summer Application www.summer.colostate.edu 2012 Summer Calendar Tues., Mar. 20 ..Summer Session

320

Assessing the Predictability of Convection using Ensemble Data Assimilation of Simulated Radar Observations in an LETKF system  

NASA Astrophysics Data System (ADS)

This study uses the Local Ensemble Transform Kalman Filter (LETKF) to perform storm-scale Data Assimilation of simulated Doppler radar observations into the non-hydrostatic, convection-permitting COSMO model. In perfect model experiments (OSSEs), it is investigated how the limited predictability of convective storms affects precipitation forecasts. The study compares a fine analysis scheme with small RMS errors to a coarse scheme that allows for errors in position, shape and occurrence of storms in the ensemble. The coarse scheme uses superobservations, a coarser grid for analysis weights, a larger localization radius and larger observation error that allow a broadening of the Gaussian error statistics. Three hour forecasts of convective systems (with typical lifetimes exceeding 6 hours) from the detailed analyses of the fine scheme are found to be advantageous to those of the coarse scheme during the first 1-2 hours, with respect to the predicted storm positions. After 3 hours in the convective regime used here, the forecast quality of the two schemes appears indiscernible, judging by RMSE and verification methods for rain-fields and objects. It is concluded that, for operational assimilation systems, the analysis scheme might not necessarily need to be detailed to the grid scale of the model. Depending on the forecast lead time, and on the presence of orographic or synoptic forcing that enhance the predictability of storm occurrences, analyses from a coarser scheme might suffice.

Lange, Heiner; Craig, George

2014-05-01

321

Storms of Mediterranean and Atlantic legends  

NASA Astrophysics Data System (ADS)

Weather extremes and notably wind storms 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 storms 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 storms 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 storms on these territories. Winds and storms 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 storms create comparable perceptions, whatever the region. Key words: wind storms, Mediterranean regions, Atlantic regions, perceptions, representations.

Schoenenwald, N.; Tabeaud, M.

2009-09-01

322

Author's personal copy Heavy air pollution suppresses summer thunderstorms  

E-print Network

Author's personal copy Heavy air pollution suppresses summer thunderstorms in central China Xin China, for assessing the impact of the increasing air pollution on convective precipitation. Adding frequency. This decrease was contributed by light and moderate (o25 mm dayÃ?1 ) rainy days. These patterns

Li, Zhanqing

323

Center for Turbulence Research Proceedings of the Summer Program 2008  

E-print Network

Center for Turbulence Research Proceedings of the Summer Program 2008 55 Bi-global secondary streaks lead to strong convective shear-layer instabilities in the wake of the roughness element. The 2-D for investigating the first stage of laminar-turbulent transition in incompressible as well as compressible shear

Prinz, Friedrich B.

324

CUSP Summer Enhancement FellowshipPracticum & Research Assistantship Summer 2013 Application CUSP SUMMER ENHANCEMENT FELLOWSHIP  

E-print Network

CUSP Summer Enhancement Fellowship­Practicum & Research Assistantship Summer 2013 Application 1 CUSP SUMMER ENHANCEMENT FELLOWSHIP FOR PRACTICUMS & RESEARCH ASSISTANTSHIPS SUMMER 2013 APPLICATION The CUSP Summer Enhancement Fellowship for Practicums & Research Assistantships is a competitive grant

Hone, James

325

Observational analysis of the interaction between a baroclinic boundary and supercell storms on 27 April 2011  

NASA Astrophysics Data System (ADS)

A thermal boundary developed during the morning to early afternoon hours on 27 April as a result of rainfall evaporation and shading from reoccurring deep convection. This boundary propagated to the north during the late afternoon to evening hours. The presence of the boundary produced an area more conducive for the formation of strong violent tornadoes through several processes. These processes included the production of horizontally generated baroclinic vorticity, increased values in storm-relative helicity, and decreasing lifting condensation level heights. Five supercell storms formed near and/or propagated alongside this boundary. Supercells that interacted with this boundary typically produced significant tornadic damage over long distances. Two of these supercells formed to the south (warm) side of the boundary and produced a tornado prior to crossing to the north (cool) side of the boundary. These two storms exhibited changes in appearance, intensity, and structure. Two other supercells formed well south of the boundary. These two storms remained relatively weak until they interacted with the boundary. These storms then rapidly intensified and produced tornadoes. Supercells that formed well into the cool side of the boundary either did not produce tornadoes or the tornadoes were determined to be weak in nature.

Sherrer, Adam Thomas

326

Effects of explicit atmospheric convection at high CO2  

PubMed Central

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

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

2014-01-01

327

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

328

Predicting Airspace Capacity Impacts Using the Consolidated Storm Prediction for Aviation  

NASA Technical Reports Server (NTRS)

Convective weather is currently the largest contributor to air traffic delays in the United States. In order to make effective traffic flow management decisions to mitigate these delays, weather forecasts must be made as early and as accurately as possible. A forecast product that could be used to mitigate convective weather impacts is the Consolidated Storm Prediction for Aviation. This product provides forecasts of cloud water content and convective top heights at 0- to 8-hour look-ahead times. The objective of this study was to examine a method of predicting the impact of convective weather on air traffic sector capacities using these forecasts. Polygons representing forecast convective weather were overlaid at multiple flight levels on a sector map to calculate the fraction of each sector covered by weather. The fractional volume coverage was used as the primary metric to determine convection s impact on sectors. Results reveal that the forecasts can be used to predict the probability and magnitude of weather impacts on sector capacity up to eight hours in advance.

Russell, Carl

2010-01-01

329

Dust storm off Western Africa  

NASA Technical Reports Server (NTRS)

The impacts of Saharan dust storms reach far beyond Africa. Wind-swept deserts spill airborne dust particles out over the Atlantic Ocean where they can enter trade winds bound for Central and North America and the Caribbean. This Moderate Resolution Imaging Spectroradiometer (MODIS) image shows a dust storm casting an opaque cloud of cloud across the Canary Islands and the Atlantic Ocean west of Africa on June 30, 2002. In general it takes between 5 and 7 days for such an event to cross the Atlantic. The dust has been shown to introduce foreign bacteria and fungi that have damaged reef ecosystems and have even been hypothesized as a cause of increasing occurrences of respiratory complaints in places like Florida, where the amount of Saharan dust reaching the state has been increasing over the past 25 years.

2002-01-01

330

Multiscale storm identification and forecast  

NASA Astrophysics Data System (ADS)

We describe a recently developed hierarchical K-Means clustering method for weather images that can be employed to identify storms at different scales. We describe an error-minimization technique to identify movement between successive frames of a sequence and we show that we can use the K-Means clusters as the minimization template. A Kalman filter is used to provide smooth estimates of velocity at a pixel through time. Using this technique in combination with the K-Means clusters, we can identify storm motion at different scales and choose different scales to forecast based on the time scale of interest. The motion estimator has been applied both to reflectivity data obtained from the National Weather Service Radar (WSR-88D) and to cloud-top infrared temperatures obtained from GOES satellites. We demonstrate results on both these sensors.

Lakshmanan, V.; Rabin, R.; DeBrunner, V.

331

Dust storm monitoring: effects on the environment, human health, and potential security conflicts  

NASA Astrophysics Data System (ADS)

Monitoring dust storms 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 summer 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 storms 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 summer. Dust storms 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 storms 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 storms in the source areas, creates hardship, hunger and forced-migration. Dust storms should be considered as an important security issue.

Davara, Fernando; de la Cruz, Antonio

2004-10-01

332

Severe storms observing satellite study  

NASA Technical Reports Server (NTRS)

Payload distribution and the attitude control system for the multi-mission modular spacecraft/StormSat configuration are discussed. The design of the advanced atmospheric sounder and imaging radiometer (AASIR) gimbal drive and its servomechanism is described. Onboard data handling, data downlink communications, and ground data handling systems are developed. Additional topics covered include: magnetic unloading at synchronous altitude, north-south stationkeeping, and the feasibility and impact of flying the microwave atmospheric sounding radiometer (MASR) as an additional payload.

Iwens, R. P.; Stern, D. A.

1976-01-01

333

Clearing the Martian air - The troubled history of dust storms  

NASA Technical Reports Server (NTRS)

This note is an attempt to resolve some misconceptions regarding the historical record of the Martian atmospheric phenomena referred to as 'dust storms,' but often called yellow storms, yellow clouds, planetwide dust storms, global dust storms, great dust storms, etc. The known frequency of planet-encircling storms will be specifically addressed. Better knowledge of the sizes, frequencies, and locations of Martian dust storms is needed for atmospheric modeling and for future mission planning.

Martin, L. J.

1984-01-01

334

Convective Cloud Systems  

NSDL National Science Digital Library

The transfer of energy between Earth's surface and the atmosphere causes all weather. Energy can be transferred through three main processes: convection, conduction, and radiation. This video explains the differences between tropical convective cloud systems formed over land and those formed over oceans. The segment is one minute nine seconds in length. A background essay and discussion questions are included.

335

Dust Storm in Southern California  

NASA Technical Reports Server (NTRS)

Along historic Route 66, just southeast of the little town of Amboy, California, lies a dried-up lake. Dry lakebeds are good sources of two things: salt and dust. In this image, the now-parched Bristol Lake offers up both. On April 12, 2007, dust storms menaced the area around Amboy. To the northwest, near Newberry Springs, California, dust hampered visibility and led to a multi-car collision on Interstate 40, killing two people and injuring several others. The same day, the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) on NASA's Terra satellite captured this image of a dust storm in the dry remains of Bristol Lake. Many small dust clouds boil up from the ground surface, casting their shadows to the northwest. A bright white cloud floating over the dust also throws its shadow onto the ground below. East of the dust storm are salt works that stand out from the surrounding landscape thanks to their straight lines and sharp angles. Dark ground surfaces alternate with mined white salt in a network of stripes. When lakes evaporate, chemicals that had been dissolved in the water stay behind, making dry lake beds an ideal place to find heavy concentrations of minerals, including salt. Besides the salt works, something else appears in stark contrast to this arid place. Lush green fields of irrigated crops appear in the east. Besides their color, their orderly arrangement reveals their human-made origin.

2007-01-01

336

Development of a severe local storm prediction system: A 60-day test of a mesoscale primitive equation model  

NASA Technical Reports Server (NTRS)

The progress and problems associated with the dynamical forecast system which was developed to predict severe storms are examined. The meteorological problem of severe convective storm forecasting is reviewed. The cascade hypothesis which forms the theoretical core of the nested grid dynamical numerical modelling system is described. The dynamical and numerical structure of the model used during the 1978 test period is presented and a preliminary description of a proposed multigrid system for future experiments and tests is provided. Six cases from the spring of 1978 are discussed to illustrate the model's performance and its problems. Potential solutions to the problems are examined.

Paine, D. A.; Zack, J. W.; Kaplan, M. L.

1979-01-01

337

VHF radar observations of mesospheric density distrubance caused by Typhoon Susan and tropical storms in the western Pacific area  

NASA Technical Reports Server (NTRS)

The atmospheric parameters from the toposphere to the middle atmosphere during Typhoon Susan and tropical storms in May and June 1988 were observed by VHF radar in Taiwan. Time-dependent wind velocities with three-dimensional profiles are plotted by processing the backscattered echo power data and the Doppler spectral width of the signal returns from the VHF radar. The propagation characteristics of the gravity waves excited by the enhanced convection motions of the storms and the density perturbations caused by this gravity wave progagation are determined.

Hung, R. J.; Tsao, Y. D.; Johnson, D. L.; Chen, A. J.; Lin, C. H.

1989-01-01

338

Variations in spectroscopic characteristics and disinfection byproduct formation potentials of dissolved organic matter for two contrasting storm events  

NASA Astrophysics Data System (ADS)

SummaryChanges in disinfection byproduct (DBP) precursors during storm events have not been intensively studied to date despite their dramatic impact on downstream drinking water supplies. For this study, variations in dissolved organic matter (DOM) spectroscopic properties and DBP formation potentials (DBPFPs), and the correlations among these various parameters, were investigated in river water samples collected under two contrasting storm event conditions (a strong summer storm versus a weak fall event). Fluorescence excitation-emission matrices (EEMs) combined with parallel factor analysis revealed that a combination of two humic-like components (C1 and C2) dominated the EEM data of the storm samples. Measured DOM characteristics and DBPFPs varied over a wider range during the more intense summer storm, exhibiting higher values of specific ultraviolet absorbance and C1/C2 ratio at high flow conditions. Variations in the fluorescence index were less pronounced during the two storm events. The spectroscopic changes were well explained by the input of terrestrial DOM sources from the surrounding catchments during the storms. Different trends of the formation potentials for trihalomethanes and haloacetic acids on the recession limb of the hydrographs suggest that the structures responsible for DBP precursors during storm events may not be the same for the two classes of DBPs. The ultraviolet light-absorbing moieties in DOM appear to play major roles in generating DBPs, as evidenced by their strong positive correlations with DBPFPs. Higher correlations with DBPFP for C1 versus C2 suggest that humic-like substances associated with more aromatic and condensed structures have a greater proclivity to generate DBP upon chlorination.

Nguyen, Hang Vo-Minh; Lee, Mi-Hee; Hur, Jin; Schlautman, Mark A.

2013-02-01

339

Saturn's Great White Storm (2010): Correlations between Clouds and Thermal Fields?  

NASA Astrophysics Data System (ADS)

It is well known that convective storms occur regularly in Saturn's atmosphere, but giant storm outbreaks, known as Great White Spot (GWS) outbreaks, occur approximately every 29 years or once per Saturnian year, just past northern solstice. Including the recent GWS outbreak of December 2010, a total of six have occurred, and are considered to be related to the changing seasonal insolation, though their triggers are not yet known or what occurs below the clouds on smaller temporal and spatial timelines. Although not predictable, as evidenced by the current Northern Storm and observed by Cassini, the great storms start out with a violent outbreak, dredging up material from the deep atmosphere, which then is dispersed by the prevailing winds. The recent 2010 December GWS outbreak is an outlier, occurring at northern latitudes of approximately 35°N (the northern "Tornado Alley"), just past vernal equinox, almost a season early. It has rapidly encircled the planet in two months and is now in its mature phase, with discrete structure obvious at all longitudes at both mid-infrared and deep atmosphere (or 5-microns). Recent amateur observations indicate a link between lightning strikes, convective storm activity, GWS and spoke activity in the morning ansa (Delacroix et al., 2011). We shall explore correlations between the many visible/CCD observations from the amateur community, the albedo and thermal maps produced with data acquired from NASA/InfraRed Telescope Facility (IRTF)/NSFCAM2, a 1 - 5-micron imager, during the various phases of the 2010 - 2011 GWS. We will characterize changes in the local environs of the outbreak site at various epochs and compare with other locations on the planet. Delacroix, M., E. Kraaikamp and P. Yanamandra-Fisher,2011. First Ground Observations of Saturn's Spokes Around 2009 Equinox. EPSC/DPS, Nantes, France.

Momary, T.; Yanamandra-Fisher, P. A.; Orton, G. S.; Baines, K. H.; Fletcher, L.; Trinh, S.; Delcroix, M.

2011-12-01

340

The North Alabama Lightning Mapping Array: Recent Severe Storm Observations and Future Prospects  

NASA Technical Reports Server (NTRS)

The North Alabama Lightning Mapping Array became operational in November 2001 as a principal component of a severe weather test bed to infuse new science and technology into the short-term forecasting of severe and hazardous weather, principally within nearby National Weather Service forecast offices. Since the installation of the LMA, it has measured the total lightning activity of a large number of severe weather events, including three supercell tornado outbreaks, two supercell hailstorm events, and numerous microburst-producing storms and ordinary non-severe thunderstorms. The key components of evolving storm morphology examined are the time rate-of-change (temporal trending) of storm convective and precipitation characteristics that can be diagnosed in real-time using NEXRAD WSR-88D Doppler radar (echo growth and decay, precipitation structures and velocity features, outflow boundaries), LMA (total lightning flash rate and its trend) and National Lightning Detection Network (cloud-to- ground lightning, its polarity and trends). For example, in a transitional season supercell tornado outbreak, peak total flash rates for typical supercells in Tennessee reached 70-100/min, and increases in the total flash rate occurred during storm intensification as much as 20-25 min prior to at least some of the tornadoes. The most intense total flash rate measured during this outbreak (over 800 flashes/min) occurred in a storm in Alabama. In the case of a severe summertime pulse thunderstorm in North Alabama, the peak total flash rate reached 300/min, with a strong increase in total lightning evident some 9 min before damaging winds were observed at the surface. In this paper we provide a sampling of LMA observations and products during severe weather events to illustrate the capability of the system, and discuss the prospects for improving the short-term forecasting of convective weather using total lightning data.

Goodman, S. J.; Blakeslee, R.; Christian, H.; Koshak, W.; Bailey, J.; Hall, J.; McCaul, E.; Buechler, D.; Darden, C.; Burks, J.

2004-01-01

341

Electrical structure in thunderstorm convective regions 1. Mesoscale convective systems  

Microsoft Academic Search

Electric field (E) soundings through convective regions of mesoscale convective sys- tems (MCSs) are examined in this paper. Ten E soundings through updrafts in MCS convective regions and five soundings in MCS convective regions outside updrafts are used to show that a typical electrical structure exists in this region. These 15 E soundings plus one other previously published sounding, which

Maribeth Stolzenburg; W. David Rust; Bradley F. Smull; Thomas C. Marshall

1998-01-01

342

A Superposed Epoch Analysis of Geomagnetic Storms over a Solar Cycle: Geomagnetic and Solar Wind Data, Radar Backscatter & Auroral Imagery  

NASA Astrophysics Data System (ADS)

Geomagnetic storms - episodes of intense solar wind-magnetosphere coupling usually associated with extreme conditions in the solar wind such as coronal mass ejections (CMEs) or co-rotating interaction regions (CIRs) - cause large global disturbances in the Earth’s magnetosphere. During such storms, large amounts of energy are deposited in the magnetotail and inner magnetosphere, producing an enhanced ring current and energising plasma to relativistic levels by as yet unknown excitation mechanisms. By exploiting data from the Advanced Composition Explorer (ACE) spacecraft in conjunction with space- and ground-based measurements of geospace over the last solar cycle, a database of geomagnetic storms has been compiled and analysed. Here we present some statistical findings from a superposed epoch analysis of 143 events identified from the global SYM-H index. We find that the duration of the main phase of storms decreases for increasing storm size, as defined by the maximum negative excursion of SYM-H, contrary to the results of previous studies. We also discuss a comparison of CME and CIR driven storms in terms of storm size, phase duration and evolution, and the associated solar wind-magnetosphere coupling. Initial work has successfully identified characteristic radar backscatter observed by the Super Dual Auoral Radar Network (SuperDARN) and, in particular, the new lower-latitude StormDARN radar network during these storm-time conditions. Here we present early findings of a superposed epoch analysis of auroral imagery from the IMAGE spacecraft and ionospheric convection maps from the SuperDARN radar network. This work further illustrates the storm-time coupling between the solar wind and magnetosphere, and develops the relationship between auroral oval radius and the evolution of the storm-time SYM-H index first reported by Milan et al., (2009). Once completed, this will be the most complete superposed epoch analyses of storms to date, combining multiple datasets and analysis techniques. This will enable us to gain a better understanding of complex storm time processes such as the energisation of ring current plasmas.

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

2010-12-01

343

Numerical Simulations of the Ring Current During Geomagnetic Storms  

NASA Astrophysics Data System (ADS)

Recent progress in ring current modeling has shown the importance of a self-consistent treatment of particle transport along with magnetic and electric fields in the inner magnetosphere. The ring current intensity and spatial distribution are significantly affected by variations in the plasma sheet (the major source to the ring current), the cross polar cap potential, and compressions and expansions of the magnetosphere. We simulate the ion and electron ring current and plasma sheet by using the magnetically and electrically self-consistent Rice Convection Model-Equilibrium [Lemon et al., JGR, 2004] with a time-varying magnetopause driven by upstream solar wind and interplanetary magnetic (IMF) conditions and with time-varying plasma sheet distributions as boundary conditions. Examples of detailed comparisons of simulated storm events with in-situ magnetic intensities (e. g., GOES, Polar/MPA, or THEMIS) and proton flux spectra (e. g., LANL/MPA and SOPA, Polar/CAMMICE, or THEMIS) and energetic neutral atom (ENA) fluxes (e. g., TWINS) will be shown. We will also present comparisons of observed electron flux spectra with simulations based on a few simple electron loss models. These data-model comparisons test the ability of our model to characterize the ring current environment and the storm-time inner magnetospheric magnetic field.

Chen, M. W.; Lemon, C.; Guild, T. B.; Schulz, M.; Roeder, J. L.; Lui, A.; Keesee, A. M.; Goldstein, J.; Le, G.; Rodriguez, J. V.

2012-12-01

344

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

345

Characterizing storm-event nitrate fluxes in a fifth order suburbanizing watershed using in situ sensors.  

PubMed

Land use influences the distribution of nonpoint nitrogen (N) sources in urbanizing watersheds and storm events interact with these heterogeneous sources to expedite N transport to aquatic systems. In situ sensors provide high frequency and continuous measurements that may reflect storm-event N variability more accurately compared to grab samples. We deployed sensors from April to December 2011 in a suburbanizing watershed (479 km2) to characterize storm-event nitrate-N (NO3-N) and conductivity variability. NO3-N concentrations exhibited complex patterns both within and across storms and shifted from overall dilution (source limitation) before summer baseflows to subsequent periods of flushing (transport limitation). In contrast, conductivity generally diluted with increasing runoff. Despite diluted NO3-N concentrations, NO3-N fluxes consistently increased with flow. Sensor flux estimates for the entire deployment period were similar to estimates derived from weekly and monthly grab samples. However, significant differences in flux occurred at monthly time scales, which may have important implications for understanding impacts to temporally sensitive receiving waters. Evidence of both supply (nutrient-poor) and transport (nutrient-rich) limitation patterns during storms is consistent with watersheds undergoing land use transitions. Tracking shifts in these patterns could indicate N accumulation in developing watersheds and help identify mitigation opportunities prior to N impairment. PMID:24945442

Carey, Richard O; Wollheim, Wilfred M; Mulukutla, Gopal K; Mineau, Madeleine M

2014-07-15

346

Impact of Hurricane Rita storm surge on sugarcane borer (Lepidoptera: Crambidae) management in Louisiana.  

PubMed

Twelve thousand to 16,000 ha of Louisiana sugarcane (Saccharum spp.) fields were flooded by saltwater from the Hurricane Rita storm surge in September 2005. A four treatment, 12-replication study comparing storm surge flooded and nonflooded plant and ratoon sugarcane fields was conducted during summer 2006 to assess sugarcane borer, Diatraea saccharalis (F.), pest severity, pest control actions, and soil-associated arthropod abundance and diversity. Even with a significant 2.4-fold increase in the average number of insecticide applications used for D. saccharalis management in flooded fields, growers still incurred higher injury. A significant 2.8-fold reduction in the predaceous red imported fire ant, Solenopsis invicta Buren, was associated with the storm surge, whereas no reduction in abundance of other soil-associated arthropods was recorded. Arthropod diversity measured by the Shannon diversity index significantly increased by a factor of 1.3 in sugarcane fields flooded by the storm surge. Increase in D. saccharalis pest severity associated with the storm surge caused an estimated loss in revenue between $1.9 and $2.6 million to the Louisiana sugarcane industry for the 2006 production season. PMID:19610419

Beuzelin, J M; Reagan, T E; Akbar, W; Cormier, H J; Flanagan, J W; Blouin, D C

2009-06-01

347

The relative influence of aerosols and the environment on organized tropical and midlatitude deep convection  

NASA Astrophysics Data System (ADS)

In this two-part study, the relative impacts of aerosols and the environment on organized deep convection, including tropical sea-breeze convection and midlatitude supercellular and multicellular deep convection, are investigated within idealized cloud-resolving modeling simulations using the Regional Atmospheric Modeling System (RAMS). Part one explores aerosol-cloud-land surface interactions within tropical deep convection organized along a sea breeze front. The idealized RAMS domain setup is representative of the coastal Cameroon rainforest in equatorial Africa. In order to assess the potential sensitivity of sea-breeze convection to increasing anthropogenic activity and deforestation occurring in such regions, 27 total simulations are performed in which combinations of enhanced aerosol concentrations, reduced surface roughness length, and reduced soil moisture are included. Both enhanced aerosols and reduced soil moisture are found to individually reduce the precipitation due to reductions in downwelling shortwave radiation and surface latent heat fluxes, respectively, while perturbations to the roughness length do not have a large impact on the precipitation. The largest soil moisture perturbations dominate the precipitation changes due to reduced low-level moisture available to the convection, but if the soil moisture perturbation is moderate, synergistic interactions between soil moisture and aerosols enhance the sea breeze precipitation. This is found to result from evening convection that forms ahead of the sea breeze only when both effects are present. Interactions between the resulting gust fronts and the sea breeze front locally enhance convergence and therefore the rainfall. Part two of this study investigates the relative roles of midlevel dryness and aerosols on supercellular and multicellular convective morphology. A common storm-splitting situation is simulated wherein the right-moving storm becomes a dominant supercell and the left-moving storm evolves into a multicellular cluster. The right-mover, which is a classic (CL) supercell in the control simulation, becomes a low-precipitation (LP) supercell with increasing dryness aloft. Different midlevel hail growth mechanisms are found to dominate in the CL and LPs that assist in explaining their varying surface precipitation distributions. Although the CL and LP supercells are dynamically similar, their microphysical structure differs due to the strong control that midlevel dryness exerts on supercell morphology; aerosols have little impact on the supercellular structure. On the other hand, while midlevel dryness also dominates the changes to the multicellular convection, aerosols influence the precipitation through feedbacks to the cold pool strength and subsequent dynamical forcing. Overall, aerosol impacts are largest for the most weakly organized convection (tropical sea breeze convection) and smallest for strongly dynamic convection (supercells). Additionally, aerosol impacts are modulated by environmental influences, most notably soil moisture availability and midlevel moisture content in this study.

Grant, Leah Danielle

348

Magneto-convection.  

PubMed

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

Stein, Robert F

2012-07-13

349

The storm-time equatorial electrojet  

NASA Technical Reports Server (NTRS)

A Petrel rocket carrying a double cell rubidium magnetometer was launched from the Thumba Equatorial Rocket Launching Station during the early main phase of a magnetic storm. No ionospheric currents associated with the storm were observed and the large field depression, at the flight time, must therefore be attributed to currents at higher altitudes. The equatorial enhancement of ionospheric magnetic storm currents, predicted on the basis of theory and earlier ground data, was not observed.

Burrows, K.; Sastry, T. S. G.; Sampath, S.; Stolarik, J. D.; Usher, M. J.

1976-01-01

350

The storm-time equatorial electrojet  

NASA Technical Reports Server (NTRS)

A Petrel rocket carrying a double cell rubidium magnetometer was launched from the Thumba Equatorial Rocket Launching Station during the early main phase of a magnetic storm. No ionospheric currents associated with the storm were observed, and the large field depression at the flight time must therefore be attributed to currents at higher altitudes. The equatorial enhancement of ionospheric magnetic storm currents, predicted on the basis of theory and earlier ground data, was not observed.

Burrows, K.; Sastry, T. S. G.; Sampath, S.; Stolarik, J. D.; Usher, M. J.

1977-01-01

351

Sustainable Development Summer Intern Report 2010 Sustainable Development Summer Intern  

E-print Network

Sustainable Development Summer Intern Report 2010 1 Sustainable Development Summer Intern Final of Bishop's University. The role of the Sustainable Development Summer Intern (SDSI) is to coordinate and organize sustainable development information and activities during the summer months. Ensuring

352

On the watch for geomagnetic storms  

USGS Publications Warehouse

Geomagnetic storms, induced by solar activity, pose significant hazards to satellites, electrical power distribution systems, radio communications, navigation, and geophysical surveys. Strong storms can expose astronauts and crews of high-flying aircraft to dangerous levels of radiation. Economic losses from recent geomagnetic storms have run into hundreds of millions of dollars. With the U.S. Geological Survey (USGS) as the lead agency, an international network of geomagnetic observatories monitors the onset of solar-induced storms and gives warnings that help diminish losses to military and commercial operations and facilities.

Green, Arthur W.; Brown, William M., III

1997-01-01

353

Statistical Prediction of the Storm Surge Associated with Cool Weather Storms at The  

E-print Network

1 Statistical Prediction of the Storm Surge Associated with Cool Weather Storms at The Battery, New and the storm composite significant wave height. Data from publicly available retrospective forecasts of sea includes an error correction and to water gauge observations taken at The Battery, N.Y. The mean difference

Frei, Allan

354

Anthropolog Summer 2011  

E-print Network

was interviewed extensively on the topic of forensic anthropology for the first pro- gram of the Smithsoniapage 1 Anthropolog Summer 2011 Newsletter of The Department of Anthropology National Museum of Natural History SUMMER INSTITUTE IN MUSEUM ANTHROPOLOGYIN ITSTHIRDYEAR The Summer Institute in MuseumAnthropology

Mathis, Wayne N.

355

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

356

Summer Programs for Educators  

ERIC Educational Resources Information Center

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

Curriculum Review, 2009

2009-01-01

357

BUILD Summer Program 2014  

E-print Network

BUILD Summer Program 2014 Becca Heinen, an undergraduate from Marquette University is testing stimulator , including the battery, in hopes of reducing its size. #12;BUILD Summer Program 2014 Criselda-threatening arrhythmias. #12;BUILD Summer Program 2014 Brendan Ryan, an undergraduate from Marquette University is using

358

Summer 2013 Pingree Park  

E-print Network

Summer 2013 Pingree Park NR 220-Natural Resource Ecology & Measurements REGISTRATION PROCEDURES 1. Registration will occur through RamWeb. Registration for summer courses begins March 26. (Make sure you choose the Summer Session as RamWeb may default to Fall semeseter.) 2. Registration priority is as follows: Fish

359

SUMMER RESEARCH INTERNSHIPS--2009  

E-print Network

AGEP SUMMER RESEARCH INTERNSHIPS--2009 For information and an application, go to: http activities with McNair Scholars · Enjoy summer in beautiful Fort Collins on the Rocky Mountain foothills, or mathematics (STEM) are invited to apply for an excep- tional summer research experience at Colo- rado State

360

International Summer School2014  

E-print Network

International Summer School2014 #12;#12;Contents About Dalian University of Technology 3 About International Summer Camp 11 Session 3 Intensive Training on Chinese Language 15 About Dalian 19 #12;#12;About for International Students Education". The non-degree seeking programs at DUT include International Summer School

Haviland, David

361

Summer International Student Tutorial  

E-print Network

Summer International Student Tutorial #12;This tutorial will help you... Welcome to UC Berkeley targeted for Summer Sessions-only students Wednesday, May 28 | 12-1pm International House Auditorium Summer Sessions! ...understand your documents and visa requirements ...become familiar with resources

Jacobs, Lucia

362

2014 Summer Transportation Institute  

E-print Network

coordinator, interns and industry professionals. Students must: ·beinthe7th,8thor9thgradeforthe2014-20152014 Summer Transportation Institute See where the Summer Transportation Institute can take you! The University of Rhode Island Transportation Center will host two two-week sessions of the Summer Transportation

Rhode Island, University of

363

Overview of the Convection and Moisture Experiment(CAMEX)  

NASA Technical Reports Server (NTRS)

The goal of this paper is to present an overview of the Convection and Moisture Experiment including CAMEX-3 and CAMEX-4 field campaigns including field operations, aircraft platforms and instrumentation, aircraft missions, and data acquired during 1998 and 2001 field phases. A total of eight tropical storms and hurricanes were investigated during the CAMEX field campaigns including Bonnie, Danielle, Earl, and Georges during 1998 and Chantal, Erin, Gabrielle, and Humberto during 2001. Most of these storms were sampled with aircraft over the open ocean, but Bonnie (1998), Georges (1998), and Gabrielle (2001) also provided opportunities to monitor landfalling impacts. A few of the storms were sampled on multiple occasions during a course of several days. Most notably of these was Hurricane Humberto, which was sampled on three consecutive days during a cycle of both increasing and decreasing intensity change. Information collected for each of the eight CAMEX tropical storms as well the TRMM validation activities have been archived and are readily available for distribution at the CAMEX web site.

Kakar, Ramesh; Goodman, Michael; Hood, Robbie; Guillory, Anthony

2003-01-01

364

Overview of the Convection and Moisture Experiment (CAMEX)  

NASA Technical Reports Server (NTRS)

This paper presents an overview of the Convection and Moisture Experiment (CAMEX), including the field operations, aircraft platforms and missions, instrumentation, and data acquired during 1998 and 2001 field campaigns. A total of eight tropical storms and hurricanes were investigated during the CAMEX field campaigns including Bonnie, Danielle, Earl, and Georges during 1998 and Chantal, Erin, Gabrielle, and Humberto during 2001. Most of these storms were sampled with aircraft over the open ocean, but Hurricanes Bonnie (1998), Georges (1998), and Gabrielle (2001) also provided opportunities to monitor landfalling impacts. A few of the storms were sampled on multiple occasions during a course of several days. Most notable of these was Hurricane Humberto, which was sampled on three consecutive days during a cycle of both increasing and decreasing intensity change. Information collected for each of the eight CAMEX tropical storms as well as the Tropical Rainfall Measuring Mission validation activities are accessible via the CAMEX Web site and archived at the National Aeronautics and Space Administration Marshall Space Flight Center.

Kakar, Ramesh; Goodman, Michael; Hood, robbie; Guillory, Anthony

2006-01-01

365

Observation of moist convection in Jupiter's atmosphere. Galileo Imaging Team  

PubMed

The energy source driving Jupiter's active meteorology is not understood. There are two main candidates: a poorly understood internal heat source and sunlight. Here we report observations of an active storm system possessing both lightning and condensation of water. The storm has a vertical extent of at least 50 km and a length of about 4,000 km. Previous observations of lightning on Jupiter have revealed both its frequency of occurrence and its spatial distribution, but they did not permit analysis of the detailed cloud structure and its dynamics. The present observations reveal the storm (on the day side of the planet) at the same location and within just a few hours of a lightning detection (on the night side). We estimate that the total vertical transport of heat by storms like the one observed here is of the same order as the planet's internal heat source. We therefore conclude that moist convection-similar to large clusters of thunderstorm cells on the Earth-is a dominant factor in converting heat flow into kinetic energy in the jovian atmosphere. PMID:10688191

Gierasch; Ingersoll; Banfield; Ewald; Helfenstein; Simon-Miller; Vasavada; Breneman; Senske

2000-02-10

366

A Personal Storm Warning Service  

NASA Technical Reports Server (NTRS)

Although lightning detection systems operated by government agencies, utilities and other businesses provide storm warnings, this information often does not reach the public until some time after the observations have been made. A low-cost personal lightning detector offers a significant safety advantage to private flyers, boaters, golfers and others. Developed by Airborne Research Associates, the detectors originated in Space Shuttle tests of an optical lightning detection technique. The commercial device is pointed toward a cloud to detect invisible intracloud lightning by sensing subtle changes in light presence. The majority of the sales have been to golf courses. Additional products and more advanced applications are in progress.

1994-01-01

367

Summer Term Percent of Refund  

E-print Network

Summer Term Dates Percent of Refund Due Summer Term Dates Percent of Refund Due May 14, 2012 100 withdraw from the Institute by the specified date listed below. Refund Schedule Full Summer Session Summer

Li, Mo

368

The Gravity Wave Response Above Deep Convection in a Squall Line Simulation  

NASA Technical Reports Server (NTRS)

High-frequency gravity waves generated by convective storms likely play an important role in the general circulation of the middle atmosphere. Yet little is known about waves from this source. This work utilizes a fully compressible, nonlinear, numerical, two-dimensional simulation of a midlatitude squall line to study vertically propagating waves generated by deep convection. The model includes a deep stratosphere layer with high enough resolution to characterize the wave motions at these altitudes. A spectral analysis of the stratospheric waves provides an understanding of the necessary characteristics of the spectrum for future studies of their effects on the middle atmosphere in realistic mean wind scenarios. The wave spectrum also displays specific characteristics that point to the physical mechanisms within the storm responsible for their forcing. Understanding these forcing mechanisms and the properties of the storm and atmosphere that control them are crucial first steps toward developing a parameterization of waves from this source. The simulation also provides a description of some observable signatures of convectively generated waves, which may promote observational verification of these results and help tie any such observations to their convective source.

Alexander, M. J.; Holton, J. R.; Durran, D. R.

1995-01-01

369

2.0 Storm Water Pollution Prevention Team  

E-print Network

Sample SWPPP Note: a DNR storm water permit does not require use of this particular Storm Water Pollution Prevention Plan (SWPPP). This SWPPP is provided solely for voluntary use by industrial storm water permittees.

unknown authors

370

Convection in the magnetotail  

NASA Astrophysics Data System (ADS)

It is well known that the Earth's magnetosphere is permeated by a large-scale electric field, E, which in its turn produces a global flow pattern known as magnetospheric convection, with velocity u = (E × B)/B2 . Convection is the key to understanding the global features of the magnetosphere, for instance the large-scale flow of electric currents along magnetic field lines (“Birkeland currents”) into and out of the polar ionosphere.A successful theory of convection in the inner magnetosphere was formulated about 20 years ago. That, however, explains only part of the puzzle, because the inner magnetosphere receives its E from more distant regions, mainly the magnetotail and its boundary layers, where convection is still poorly understood. One problem has been the Erickson-Wolf effect [Erickson and Wolf, 1980; Hau et al., 1989] by which convection rapidly deforms the tail until a reconnection crisis is likely. Another problem was the observational uncertainty about the polytropic (or “adiabatic”) exponent ? of the gas law expected to hold in the plasma sheet [Zhu, 1990; Baumjohann and Paschmann, 1989; Huang et al., 1989]. MHD simulations appear to be of limited use, because convection theory in the inner magnetosphere goes beyond MHD and depends on actualparticle motion. In the weak fields of the magnetotail, these may involve not only guiding center drifts but also nonadiabatic motions [e.g., Büchner and Zelenyi, 1989] and finite-gyroradius effects [Macmahon, 1965; Stasiewicz, 1987].

Stern, David

371

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

NASA Technical Reports Server (NTRS)

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

2004-01-01

372

Coastal storm monitoring in Virginia  

USGS Publications Warehouse

Coastal communities in Virginia are prone to flooding, particularly during hurricanes, nor’easters, and other coastal low-pressure systems. These weather systems affect public safety, personal and public property, and valuable infrastructure, such as transportation, water and sewer, and electric-supply networks. Local emergency managers, utility operators, and the public are tasked with making difficult decisions regarding evacuations, road closures, and post-storm recovery efforts as a result of coastal flooding. In coastal Virginia these decisions often are made on the basis of anecdotal knowledge from past events or predictions based on data from monitoring sites located far away from the affected area that may not reflect local conditions. Preventing flood hazards, such as hurricane-induced storm surge, from becoming human disasters requires an understanding of the relative risks that flooding poses to specific communities. The risk to life and property can be very high if decisions about evacuations and road closures are made too late or not at all.

Wicklein, Shaun M.; Bennett, Mark R.

2014-01-01

373

Saturn’s visible lightning, its radio emissions, and the structure of the 2009-2011 lightning storms  

NASA Astrophysics Data System (ADS)

Visible lightning on Saturn was first detected by the Cassini camera in 2009 at ?35° South latitude. We report more lightning observations at ?35° South later in 2009, and lightning in the 2010-2011 giant lightning storm at ?35° North. The 2009 lightning is detected on the night side of Saturn in a broadband clear filter. The 2011 lightning is detected on the day side in blue wavelengths only. In other wavelengths the 2011 images lacked sensitivity to detect lightning, which leaves the lightning spectrum unknown. The prominent clouds at the west edge, or the “head” of the 2010-2011 storm periodically spawn large anticyclones, which drift off to the east with a longitude spacing of 10-15° (?10,000 km). The wavy boundary of the storm’s envelope drifts with the anticyclones. The relative vorticity of the anticyclones ranges up to -f/3, where f is the planetary vorticity. The lightning occurs in the diagonal gaps between the large anticyclones. The vorticity of the gaps is cyclonic, and the atmosphere there is clear down to level of the deep clouds. In these respects, the diagonal gaps resemble the jovian belts, which are the principal sites of jovian lightning. The size of the flash-illuminated cloud tops is similar to previous detections, with diameter ?200 km. This suggests that all lightning on Saturn is generated at similar depths, ?125-250 km below the cloud tops, probably in the water clouds. Optical energies of individual flashes for both southern storms and the giant storm range up to 8 × 109 J, which is larger than the previous 2009 equinox estimate of 1.7 × 109 J. Cassini radio measurements at 1-16 MHz suggest that, assuming lightning radio emissions range up to 10 GHz, lightning radio energies are of the same order of magnitude as the optical energies. Southern storms flash at a rate ?1-2 per minute. The 2011 storm flashes hundreds of times more often, ?5 times per second, and produces ?1010 W of optical power. Based on this power, the storm’s total convective power is of the order 1017 W, which is uncertain by at least an order of magnitude, and probably is underestimated. This power is similar to Saturn’s global internal power radiated to space. It suggests that storms like the 2010-2011 giant storm are important players in Saturn’s cooling and thermal evolution.

Dyudina, Ulyana A.; Ingersoll, Andrew P.; Ewald, Shawn P.; Porco, Carolyn C.; Fischer, Georg; Yair, Yoav

2013-09-01

374

High latitude TEC fluctuations and irregularity oval during geomagnetic storms  

NASA Astrophysics Data System (ADS)

GPS measurements obtained by the global IGS network were used to study the occurrence of TEC fluctuations in the northern and southern high-latitude ionosphere during severe geomagnetic storms. In the northern hemisphere, GPS stations located higher than 55N Corrected Geomagnetic Latitude (CGL) at different longitudes were selected. In the southern hemisphere, Antarctic permanent GPS stations were used. Dual-frequency GPS measurements for individual satellite passes served as raw data. As a measure of fluctuation activity the rate of TEC (ROT) was used, and the fluctuation intensity was evaluated using the ROTI index. Using daily GPS measurements from all selected stations, images of the spatial and temporal behavior of TEC fluctuations were formed (in Corrected Geomagnetic Coordinates-CGC and geomagnetic local time-GLT). Similarly to the auroral oval, these images demonstrate an irregularity oval. The occurrence of the irregularity oval relates to the auroral oval, cusp and polar cap. During a storm, the intensity of TEC fluctuations essentially increased. The irregularity oval expands equatorward with an increase of magnetic activity. The study showed that the existing high-latitude GPS stations can provide a permanent monitoring tool for the irregularity oval in near real-time. In this paper, the features of the development of phase fluctuations at the geomagnetic conjugate points, and inter-hemispheric differences and similarities during winter and summer conditions, are discussed.

Shagimuratov, I. I.; Krankowski, A.; Ephishov, I.; Cherniak, Yu.; Wielgosz, P.; Zakharenkova, I.

2012-06-01

375

The wet-snow storm of 10 September 2012  

NASA Astrophysics Data System (ADS)

On 10 September 2012 an extreme wet-snow storm occured in Iceland in relation with the "first" autumn low of 2012. Very strong northwesterly winds, high precipitation and temperatures close to 0°C caused widespread damage in North and Northeast-Iceland, disruption to traffic and loss of livestock. At sea level the precipitation fell as rain and the damage was limited to that caused by the high winds. At an elevation of up to a few hundred metres, the precipitation fell as very wet snow, causing extreme and well documented accretion on the electric transmission and distribution system in the region as well as on other structures. Up to 40 masts of the transmission system and about 150 poles of the distribution system broke or were damaged in other ways, causing a widespread electric outage of up to 48 hours. Furthermore, thousands of sheep still out for summer grazing were lost and in many cases burried under metres of snow. The storm was reasonably well forecasted several days in advance but the greatest error was associated with an overestimated temperature. Hence, rain instead of heavy wet snowfall was expected by many. The event has been successfully simulated at high resolution using an atmospheric numerical model and we present an analysis of the event based on the simulations and observational data. Similar events have happened a few times in the last decades.

Ágústsson, Hálfdán; Ólafsson, Haraldur; Jón Elíasson, Árni; Þorsteins, Egill

2013-04-01

376

Storm Surge Sensor During Hurricane Irene  

USGS Multimedia Gallery

During hurricanes the USGS deploys storm-surge monitoring instruments along the coasts, sounds, and bays in impacted areas to gauge how high hurricanes push water in rivers, bays and other areas. The sensors are crucial for forecasting future storms and assessing hurricane damage. They are strapped ...

377

Winter Icing and Storms Project (WISP)  

Microsoft Academic Search

Field studies in support of the Winter Icing and Storms Project (WISP) were conducted in the Colorado Front Range area from 1 February to 31 March 1990(WISP90) and from 15 January to 5 April 1991 (WISP91). The main goals of the project are to study the processes leading to the formation and depletion of supercooled liquid water in winter storms

Roy Rasmussen; Marcia Politovich; John Marwitz; Wayne Sand; John McGinley; John Smart; Roger Pielke; Steve Rutledge; Doug Wesley; Greg Stossmeister; Ben Bernstein; Kim Elmore; Nick Powell; Ed Westwater; B. Boba Stankov; Don Burrows

1992-01-01

378

Low-energy ion precipitation during the Halloween storm  

NASA Astrophysics Data System (ADS)

During the Halloween storm of October 29 31, 2003, four defense meteorological satellite program (DMSP) satellites detected fluxes of low-energy ions precipitating well equatorward of auroral electrons in the dawn/morning magnetic local time sector during the main phase. There were three southward turnings of the interplanetary magnetic field (IMF), leading to three intensifications of the ring current to DST values of -125, -310 and -350 nT. In each case the ion fluxes weakened dramatically and/or vanished during DST recoveries. DMSP only encountered short-lived episodes of subauroral ion precipitation in the dusk/evening sector. A brief survey of the DMSP database reveals that near-dawn, ion precipitation is a main-phase characteristic of all large magnetic storms. DMSP satellites also detected similar ion precipitation during the main phase of the March 1991 magnetic storm. During an outbound pass of the combined release radiation effect satellite (CRRES) through the inner magnetosphere it detected low energy (<1 keV) ion fluxes that were collocated with, but spectrally separated in energy from the ring current “nose structure”. As CRRES moved toward perigee in the dawn sector, it crossed similar low-energy (?500 eV) ions embedded in a broad ion population, located earthward of plasma sheet electrons. Simultaneously the DMSP F8 satellite detected spectrally similar low-energy ions precipitating at subauroral latitudes near dawn at the same invariant latitudes. To reconcile DMSP/CRRES observations with elementary concepts of allowed ion drift paths, the data suggest two source populations. The lowest-energy ions, of ionospheric origin, were initially energized earthward of the plasma sheet electron boundary in the evening local-time sector then co-rotated eastward. Higher-energy ions originated in the plasma sheet and drifted close to the Earth under the combined influences of time-varying convective electric fields and azimuthal gradients in the Earth's magnetic field generated by the stormtime ring current [Tsyganenko, N.A., Singer, H. J., Kasper, J. C., 2003. Storm-time distortion of the inner magnetosphere: how severe can it get? Journal of Geophysical Research, 108 (A5), 1209].

Huang, C. Y.; Burke, W. J.; Lin, C. S.

2007-02-01

379

Pattern formation of crystals in storm glass  

NASA Astrophysics Data System (ADS)

"Storm glass" is a sealed glass tube containing a camphor-ethanol solution with aqueous NH 4Cl and KNO 3 solution. In 19th century England, the pattern and quantity of the crystals formed were observed and interpreted as a weather forecasting tool. In the present study, the pattern formation of the crystals in the storm glass solution was investigated by focusing on one parameter, such as the applied temperature. The growth patterns of the crystals in the storm glass solution were controlled using a directional growth apparatus and observed in situ as a function of the growth rate. Crystals grown in camphor ethanol solution were also observed for comparison. In addition, a replica of the storm glass attached to a temperature control system was constructed in order to examine the effect of the history of temperature variations on the crystals. X-ray diffraction patterns of the crystals were obtained to clarify the species of the crystals in the storm glass.

Tanaka, Yasuko; Hagano, Koichi; Kuno, Tomoyasu; Nagashima, Kazushige

2008-05-01

380

Reduction of the field-aligned potential drop in the polar cap during large geomagnetic storms  

NASA Astrophysics Data System (ADS)

We have studied photoelectron flows and the inferred field-aligned potential drop in the polar cap during 5 large geomagnetic storms that occurred in the periods when the photoelectron observations in the polar cap were available near the apogee of the FAST satellite (~4000 km) at solar maximum, and the footprint of the satellite paths in the polar cap was under sunlit conditions most of the time. In contrast to the ~20 V potential drop during geomagnetically quiet periods at solar maximum identified by Kitamura et al. [JGR, 2012], the field-aligned potential drop frequently became smaller than ~5 V during the main and early recovery phases of the large geomagnetic storms. Because the potential acts to inhibit photoelectron escape, this result indicates that the corresponding acceleration of ions by the field-aligned potential drop in the polar cap and the lobe region is smaller during the main and early recovery phases of large geomagnetic storms compared to during geomagnetically quiet periods. Under small field-aligned current conditions, the number flux of outflowing ions should be nearly equal to the net escaping electron number flux. Since ions with large flux originating from the cusp/cleft ionosphere convect into the polar cap during geomagnetic storms [e.g., Kitamura et al., JGR, 2010], the net escaping electron number flux should increase to balance the enhanced ion outflows. The magnitude of the field-aligned potential drop would be reduced to let a larger fraction of photoelectrons escape.

Kitamura, N.; Seki, K.; Nishimura, Y.; Hori, T.; Terada, N.; Ono, T.; Strangeway, R. J.

2013-12-01

381

Delineating mid- and low-level water vapor patterns in pre-convective environments using VAS moisture channels  

NASA Technical Reports Server (NTRS)

Infrared and visible imagery from VAS are used to delineate mid- and lower-tropospheric moisture fields for a variety of severe storm cases in the southern and central United States. The ability of sequences of images to isolate areas of large negative vertical moisture gradients and apparent convective instability prior to the onset of convective storms is assessed. A variety of image combination procedures are used to deduce the stability fields which are then compared with the available radiosonde data. The results for several severe storm cases indicate that VAS can detect mid- and low-level mesoscale water vapor fields as distinct radiometric signals. The VAS imagery shows a strong tendency for thunderstorms to develop along the edges of bands of midlevel dryness as they overtake either preexisting or developing low-level moisture maxima. Image sequences depict the speed with which deep moist and dry layers can develop and move.

Petersen, R. A.; Uccellini, L. W.; Mostek, A.; Keyser, D. A.

1984-01-01

382

UNIVERSITY OF ROCHESTER Summer Housing Application/Summer Housing Contract Summer 2014  

E-print Network

UNIVERSITY OF ROCHESTER Summer Housing Application/Summer Housing Contract ­ Summer 2014 Note: Once submitted, this contract is binding for the summer stays as indicated below. Living arrangement preferences summer classes Double Occupancy UR student not enrolled in summer classes Preferred Roommate: Non

Mahon, Bradford Z.

383

A case study of ionospheric storm effects during long-lasting southward IMF Bz-driven geomagnetic storm  

NASA Astrophysics Data System (ADS)

instrumental observations including GPS total electron content (TEC), foF2 and hmF2 from ionosondes, vertical ion drift measurements from Communication/Navigation Outage Forecasting System, magnetometer data, and far ultraviolet airglow measured by Thermosphere, Ionosphere, Mesosphere Energetics and Dynamics/Global Ultraviolet Imager (TIMED/GUVI) are used to investigate the profound ionospheric disturbances at midlatitude and low latitude during the 14-17 July 2012 geomagnetic storm event, which was featured by prolonged southward interplanetary geomagnetic field component for about 30 h below -10 nT. In the East Asian/Australian sector, latitudinal profile of TEC variations in the main phase were characterized by three bands of increments and separated by weak depressions in the equatorial ionospheric anomaly (EIA) crest regions, which were caused by the combined effects of disturbance dynamo electric fields (DDEF) and equatorward neutral winds. In the recovery phase, strong inhibition of EIA occurred and the summer crest of EIA disappeared on 16 July due to the combined effects of intrusion of neutral composition disturbance zone as shown by the TIMED/GUVI O/N2 measurements and long-lasting daytime westward DDEF inferred from the equatorial electrojet observations. The transit time of DDEF over the dip equator from westward to eastward is around 2200 LT. In the American longitude, the salient ionospheric disturbances in the summer hemisphere were characterized by daytime periodical intrusion of negative phase for three consecutive days in the recovery phase, preceded by storm-enhanced density plume in the initial phase. In addition, multiple short-lived prompt penetration electric fields appeared during stable southward interplanetary magnetic field (IMF) Bz in the recovery phase and were responsible for enhanced the EIA and equatorial ionospheric uplift around sunset.

Liu, Jing; Liu, Libo; Nakamura, Takuji; Zhao, Biqiang; Ning, Baiqi; Yoshikawa, A.

2014-09-01

384

Convective rainfall estimation from digital GOES-1 infrared data  

NASA Technical Reports Server (NTRS)

An investigation was conducted to determine the feasibility of developing and objective technique for estimating convective rainfall from digital GOES-1 infrared data. The study area was a 240 km by 240 km box centered on College Station, Texas (Texas A and M University). The Scofield and Oliver (1977) rainfall estimation scheme was adapted and used with the digital geostationary satellite data. The concept of enhancement curves with respect to rainfall approximation is discussed. Raingage rainfall analyses and satellite-derived rainfall estimation analyses were compared. The correlation for the station data pairs (observed versus estimated rainfall amounts) for the convective portion of the storm was 0.92. It was demonstrated that a fairly accurate objective rainfall technique using digital geostationary infrared satellite data is feasible. The rawinsonde and some synoptic data that were used in this investigation came from NASA's Atmospheric Variability Experiment, AVE 7.

Sickler, G. L.; Thompson, A. H.

1979-01-01

385

Alabama Ground Operations during the Deep Convective Clouds and Chemistry Experiment  

NASA Technical Reports Server (NTRS)

The Deep Convective Clouds and Chemistry (DC3) field campaign investigates the impact of deep, midlatitude convective clouds, including their dynamical, physical and lighting processes, on upper tropospheric composition and chemistry. DC3 science operations took place from 14 May to 30 June 2012. The DC3 field campaign utilized instrumented aircraft and ground ]based observations. The NCAR Gulfstream ]V (GV) observed a variety of gas ]phase species, radiation and cloud particle characteristics in the high ]altitude outflow of storms while the NASA DC ]8 characterized the convective inflow. Groundbased radar networks were used to document the kinematic and microphysical characteristics of storms. In order to study the impact of lightning on convective outflow composition, VHF ]based lightning mapping arrays (LMAs) provided detailed three ]dimensional measurements of flashes. Mobile soundings were utilized to characterize the meteorological environment of the convection. Radar, sounding and lightning observations were also used in real ]time to provide forecasting and mission guidance to the aircraft operations. Combined aircraft and ground ]based observations were conducted at three locations, 1) northeastern Colorado, 2) Oklahoma/Texas and 3) northern Alabama, to study different modes of deep convection in a variety of meteorological and chemical environments. The objective of this paper is to summarize the Alabama ground operations and provide a preliminary assessment of the ground ]based observations collected over northern Alabama during DC3. The multi ] Doppler, dual ]polarization radar network consisted of the UAHuntsville Advanced Radar for Meteorological and Operational Research (ARMOR), the UAHuntsville Mobile Alabama X ]band (MAX) radar and the Hytop (KHTX) Weather Surveillance Radar 88 Doppler (WSR ]88D). Lightning frequency and structure were observed in near real ]time by the NASA MSFC Northern Alabama LMA (NALMA). Pre ]storm and inflow proximity soundings were obtained with the UAHuntsville mobile sounding unit and the Redstone Arsenal (QAG) morning sounding.

Carey, Lawrence; Blakeslee, Richard; Koshak, William; Bain, Lamont; Rogers, Ryan; Kozlowski, Danielle; Sherrer, Adam; Saari, Matt; Bigelbach, Brandon; Scott, Mariana; Schultz, Elise; Schultz, Chris; Gatlin, Patrick; Wingo, Matt; Phillips, Dustin; Phillips, Chris; Peterson, Harold; Bailey, Jeff; Frederickson, Terryn; Hall, John; Bart, Nicole; Becker, Melissa; Pinkney, Kurtis; Rowe, Scott; Starzec, Mariusz

2013-01-01

386

Copper disinfection ban causes storm.  

PubMed

Since 1 February this year, under the EU's Biocidal Products Directive, it has been illegal to sell or use water treatment systems that use elemental copper, a practice employed historically by a significant number of UK healthcare facilities to combat Legionella. Alan Lester, managing director of specialist supplier of 'environmentally-friendly' water treatment systems, Advanced Hydro, says the ban has caused 'a storm of giant proportion,' with advocates of copper ion-based treatment systems arguing that this disinfection method dates back 3,000 years to Egyptian times, making it an 'undoubtedly proven' technology. Here he explains why the ban came into force, considers why the UK's Health and Safety Executive (HSE) is seeking a derogation, looks at the ban's likely impact, and gives a personal viewpoint on the 'pros and cons' of some of the alternative treatment technologies, including a titanium dioxide-based system marketed by Advanced Hydro itself in the UK. PMID:23763088

Lester, Alan

2013-05-01

387

Anomalously Weak Solar Convection  

NASA Technical Reports Server (NTRS)

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

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

2012-01-01

388

Statistical High-Latitude Convection Patterns from ISRs Observations at Millstone Hill and Sondrestrom  

NASA Astrophysics Data System (ADS)

A combined database from long-term incoherent scatter radar line-of-sight observations at Millstone Hill and Sondrestrom has been used to construct statistical patterns/models of high-latitude convections between 55 and 78 invariant latitudes in Northern America. This paper presents variations of the convection as a function of IMF By and Bz conditions and season. It is shown that the cross polar cap potential is on average higher in equinox than in solstice. As the season turns from winter to summer, the convection pattern appears to move anti-sunward and the axis across the two cells rotates toward earlier local times, meanwhile, the cross polar potential weakens for By - and vice verse for By +. The dusk-dawn cell similarity in summer is found to be high for By - and low for By +, supportive of the theory of lobe cell generation in summer. It is therefore noted that the procedure to simply switch the By sign in order to obtain the convection for the conjugate hemisphere may be not alway appropriate, because of the asymmetry of the convection response to By + and -, and of seasonal differences in the convection.

Zhang, S.; Holt, J.; Foster, J.; McCready, M.

2005-12-01

389

Nitrate transport and fluxes during storm-event discharge from a 12 ha tile-drained dryland agricultural field  

NASA Astrophysics Data System (ADS)

Tile drains shortcut natural soil hydrology and decrease the capacity of soils to buffer water and nutrient fluxes during storm events. Previous research at the Cook Agronomy Farm near Pullman, WA. found seasonal patterns for nutrient and water fluxes, larger during the winter and smaller during the summer. The objective of this study was to determine the effects storm events have on tile-drain water and nutrient fluxes from a dryland agricultural field. Our first hypothesis is that winter storm events activate shallow soil-water flow paths, resulting in rapid transport of precipitation and younger soil pore-water through the tile-drain system. These storm-event flow paths result in a decrease in tile-drain water electrical conductivity from a baseline of approximately 260 ?S/cm to as low as 20 ?S/ cm. Data suggest that storm events increase hydraulic conductivities in the upper profile as soil approaches saturation, increasing the contributions of relatively young soil water and possibly current storm-event precipitation to tile-drain discharge. Our second hypothesis is that the observed increase in discharge during storm events does not decrease nitrate concentrations in discharged water, because the storm-event flow paths also transport additional nitrate from the upper soil profile through the tile-drain system. If this hypothesis is correct, during storm events nitrate fluxes should increase, indicating rapid mobilization and potential flushing of soil nutrients through the vadose zone and tile-drain. If nitrate fluxes remain constant during storm events, then decreased tile-drain nitrate concentrations may be caused by the addition of low-nitrate or nitrate-free water. This would suggest that the nitrate leached from the system is present at the depth of the tile-drain and is not transported from near the soil surface to the tile-drain during storm-events, indicating flushing of soil nutrients from the rooting zone is not occurring at these temporal scales. Storm events in dryland agriculture are similar to irrigation events in irrigated agriculture, where increased water contents in rooting zones may increase water flows and nutrient fluxes from the rooting zone to surface and groundwater. This research will help explain how the dynamics of unsaturated flow conditions control nutrient and contaminant transport in agricultural systems.

Kelley, C. J.; Keller, C. K.; Brooks, E. S.; Smith, J. L.; Orr, C. H.; Evans, R. D.

2012-12-01

390

Dynamics of a Cytokine Storm  

PubMed Central

Six volunteers experienced severe inflammatory response during the Phase I clinical trial of a monoclonal antibody that was designed to stimulate a regulatory T cell response. Soon after the trial began, each volunteer experienced a “cytokine storm”, a dramatic increase in cytokine concentrations. The monoclonal antibody, TGN1412, raised serum concentrations of both pro- and anti-inflammatory cytokines ?? very hi?h values during the first day, while lymphocyte and monocyte concentrations plummeted. Because the subjects were healthy and had no prior indications of immune deficiency, this event provided an unusual opportunity to study the dynamic interactions of cytokines and other measured parameters. Here, the response histories of nine cytokines have been modeled by a set of linear ordinary differential equations. A general search procedure identifies parameters of the model, whose response fits the data well during the five-day measurement period. The eighteenth-order model reveals plausible cause-and-effect relationships among the cytokines, showing how each cytokine induces or inhibits other cytokines. It suggests that perturbations in IL2, IL8, and IL10 have the most significant inductive effect, while IFN-? and IL12 have the greatest inhibiting effect on other cytokine concentrations. Although TNF-? is a major pro-inflammatory factor, IFN-? and three other cytokines have faster initial and median response to TGN1412 infusion. Principal-component analysis of the data reveals three clusters of similar cytokine responses: [TNF-?, IL1, IL10], [IFN-?, IL2, IL4, IL8, and IL12], and [IL6]. IL1, IL6, IL10, and TNF-? have the highest degree of variability in response to uncertain initial conditions, exogenous effects, and parameter estimates. This study illuminates details of a cytokine storm event, and it demonstrates the value of linear modeling for interpreting complex, coupled biological system dynamics from empirical data. PMID:23049677

Yiu, Hao Hong; Graham, Andrea L.; Stengel, Robert F.

2012-01-01

391

Dynamics of a cytokine storm.  

PubMed

Six volunteers experienced severe inflammatory response during the Phase I clinical trial of a monoclonal antibody that was designed to stimulate a regulatory T cell response. Soon after the trial began, each volunteer experienced a "cytokine storm", a dramatic increase in cytokine concentrations. The monoclonal antibody, TGN1412, raised serum concentrations of both pro- and anti-inflammatory cytokines ?? very hi?h values during the first day, while lymphocyte and monocyte concentrations plummeted. Because the subjects were healthy and had no prior indications of immune deficiency, this event provided an unusual opportunity to study the dynamic interactions of cytokines and other measured parameters. Here, the response histories of nine cytokines have been modeled by a set of linear ordinary differential equations. A general search procedure identifies parameters of the model, whose response fits the data well during the five-day measurement period. The eighteenth-order model reveals plausible cause-and-effect relationships among the cytokines, showing how each cytokine induces or inhibits other cytokines. It suggests that perturbations in IL2, IL8, and IL10 have the most significant inductive effect, while IFN-? and IL12 have the greatest inhibiting effect on other cytokine concentrations. Although TNF-? is a major pro-inflammatory factor, IFN-? and three other cytokines have faster initial and median response to TGN1412 infusion. Principal-component analysis of the data reveals three clusters of similar cytokine responses: [TNF-?, IL1, IL10], [IFN-?, IL2, IL4, IL8, and IL12], and [IL6]. IL1, IL6, IL10, and TNF-? have the highest degree of variability in response to uncertain initial conditions, exogenous effects, and parameter estimates. This study illuminates details of a cytokine storm event, and it demonstrates the value of linear modeling for interpreting complex, coupled biological system dynamics from empirical data. PMID:23049677

Yiu, Hao Hong; Graham, Andrea L; Stengel, Robert F

2012-01-01

392

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

NASA Astrophysics Data System (ADS)

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 of perihelion) local and regional dust storms are more frequent and there is a higher probability of a major and possible planet-encircling dust storm occuring. Despite this there is still a lot of interannual variability and uncertainty regarding the occurence of both major and regional dust storms. The Mars Climate Sounder (MCS) instrument onboard NASA's Mars Reconnaissance Orbiter (MRO) is a two telescope 9 channel filter IR radiometer (0.3 to 45 microns), with each channel consisting of a linear array of 21 detectors. Each pixel sounds a 5km thick region of the Martian atmosphere in a limb viewing/scanning mode. We present a comparison of dust storm activity on Mars for 2007 to 2009 using MCS limb observations of changes in dust opacity. These measurements are also compared with observations and atmospheric opacity maps generated by the Thermal Emission Imaging System (THEMIS) multi-wavelength instrument onboard the Mars Odyssey spacecraft and Mars weather maps from MRO's Mars Color Imager (MARCI) for this period. Model predictions from the Mars Climate Database and simulations from the UK Mars General Circulation Model (GCM) are also used. This comparison gives us an empirical method for using MCS data directly to identify dust storm activity during this period.

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

2009-09-01

393

Analysis of Summertime Convective Initiation in Central Alabama Using the Land Information System  

NASA Technical Reports Server (NTRS)

During the summer months in the southeastern United States, convective initiation presents a frequent challenge to operational forecasters. Thunderstorm development has traditionally been referred to as random due to their disorganized, sporadic appearance and lack of atmospheric forcing. Horizontal variations in land surface characteristics such as soil moisture, soil type, land and vegetation cover could possibly be a focus mechanism for afternoon convection during the summer months. The NASA Land Information System (LIS) provides a stand-alone land surface modeling framework that incorporates these varying soil and vegetation properties, antecedent precipitation, and atmospheric forcing to represent the soil state at high resolution. The use of LIS as a diagnostic tool may help forecasters to identify boundaries in land surface characteristics that could correlate to favored regions of convection initiation. The NASA Shortterm Prediction Research and Transition (SPoRT) team has been collaborating with the National Weather Service Office in Birmingham, AL to help incorporate LIS products into their operational forecasting methods. This paper highlights selected convective case dates from summer 2009 when synoptic forcing was weak, and identifies any boundaries in land surface characteristics that may have contributed to convective initiation. The LIS output depicts the effects of increased sensible heat flux from urban areas on the development of convection, as well as convection along gradients in land surface characteristics and surface sensible and latent heat fluxes. These features may promote mesoscale circulations and/or feedback processes that can either enhance or inhibit convection. With this output previously unavailable to operational forecasters, LIS provides a new tool to forecasters in order to help eliminate the randomness of summertime convective initiation.

James, Robert S.; Case, Jonathan L.; Molthan, Andrew L.; Jedlovec, Gary J.

2011-01-01

394

Probability of occurrence of planetary ionosphere storms associated with the magnetosphere disturbance storm time events  

NASA Astrophysics Data System (ADS)

The ionospheric W index allows to distinguish state of the ionosphere and plasmasphere from quiet conditions (W = 0 or ±1) to intense storm (W = ±4) ranging the plasma density enhancements (positive phase) or plasma density depletions (negative phase) regarding the quiet ionosphere. The global W index maps are produced for a period 1999-2014 from Global Ionospheric Maps of Total Electron Content, GIM-TEC, designed by Jet Propulson Laboratory, converted from geographic frame (-87.5:2.5:87.5° in latitude, -180:5:180° in longitude) to geomagnetic frame (-85:5:85° in magnetic latitude, -180:5:180° in magnetic longitude). The probability of occurrence of planetary ionosphere storm during the magnetic disturbance storm time, Dst, event is evaluated with the superposed epoch analysis for 77 intense storms (Dst ? -100 nT) and 230 moderate storms (-100 < Dst ? -50 nT) with start time, t0, defined at Dst storm main phase onset. It is found that the intensity of negative storm, iW-, exceeds the intensity of positive storm, iW+, by 1.5-2 times. An empirical formula of iW+ and iW- in terms of peak Dst is deduced exhibiting an opposite trends of relation of intensity of ionosphere-plasmasphere storm with regard to intensity of Dst storm.

Gulyaeva, T. L.; Arikan, F.; Stanislawska, I.

2014-11-01

395

[Relationship Between Core Convective Structure and Intensity Change in Tropical Cyclones  

NASA Technical Reports Server (NTRS)

The downshear reformation of Tropical Storm Gabrielle (2001) was investigated using radar reflectivity and lightning data that were nearly continuous in time, as well as frequent aircraft reconnaissance fights. Initially the storm was a marginal tropical storm in an environment with strong 850-200 hPa vertical wind shear of 12-13 m/s and an approaching upper tropospheric trough. Both the observed outflow and an adiabatic balance model calculation showed that the radial-vertical circulation increased with time as the trough approached. Convection was highly asymmetric, with almost all radar return located in one quadrant left of downshear in the storm. Reconnaissance data show that an intense mesovortex formed downshear of the original center. This vortex was located just south of: rather than within, a strong downshear left lightning outbreak, consistent with tilting of the horizontal vorticity associated with the vertical wind shear. The downshear mesovortex contained a 972 hPa minimum central pressure, 20 hPa lower than minimum pressure in the original vortex just three hours earlier. The mesovortex became the new center of the storm, but weakened somewhat prior to landfall. It is argued that dry air carried around the storm from the region of upshear subsidence, as well as the direct effects of the shear, prevented the reformed vortex from continuing to intense.

2004-01-01

396

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

397

Stability of subsea pipelines during large storms.  

PubMed

On-bottom stability design of subsea pipelines transporting hydrocarbons is important to ensure safety and reliability but is challenging to achieve in the onerous metocean (meteorological and oceanographic) conditions typical of large storms (such as tropical cyclones, hurricanes or typhoons). This challenge is increased by the fact that industry design guidelines presently give no guidance on how to incorporate the potential benefits of seabed mobility, which can lead to lowering and self-burial of the pipeline on a sandy seabed. In this paper, we demonstrate recent advances in experimental modelling of pipeline scour and present results investigating how pipeline stability can change in a large storm. An emphasis is placed on the initial development of the storm, where scour is inevitable on an erodible bed as the storm velocities build up to peak conditions. During this initial development, we compare the rate at which peak near-bed velocities increase in a large storm (typically less than 10(-3)?m?s(-2)) to the rate at which a pipeline scours and subsequently lowers (which is dependent not only on the storm velocities, but also on the mechanism of lowering and the pipeline properties). We show that the relative magnitude of these rates influences pipeline embedment during a storm and the stability of the pipeline. PMID:25512592

Draper, Scott; An, Hongwei; Cheng, Liang; White, David J; Griffiths, Terry

2015-01-28

398

Observations and Simulations of the M-I Coupling of Bursty Convection  

NASA Technical Reports Server (NTRS)

The ultimate aim of the project is to establish how much of the magnetotail's total potential is due to flow bursts and how much of this potential maps to the ionosphere. In order to quantify these contributions, we further developed a method to measure the total cross-polar cap potential and the total reconnection rate across the entire polar cap boundary. Then we applied the method to different solar wind-magnetosphere-ionosphere conditions that included substorm periods, storms, and steady magnetospheric convection (SMCs, also known as convection bays) periods. In the following section, we describe in more detail the activities during the second year of this grant.

Sanchez, Ennio R.

2001-01-01

399

SUMMER SESSION STUDENT POLICY 2014 SIENA SUMMER SESSION  

E-print Network

SUMMER SESSION STUDENT POLICY ­ 2014 SIENA SUMMER SESSION The academic Summer Session is administered annually by the Office of Academic Affairs (Summer Session Coordinator), with coordination through during Summer 2014: two 4 week terms; one 6 week term; and an 8 week term. An additional July 2014 term

400

Summer Quarter~tu~J at tbe OW tbis summer  

E-print Network

---------- #12;Summer Quarter~tu~J at tbe OW tbis summer Summer is aspecial time to learn at the University of Washington. There is no summer enrollment limit, so admission is open to all qualified one of the nation's largest summer programs, including more than 1,500 courses in over 100 fields

Kaminsky, Werner

401

The Kinematic and Microphysical Control of Storm Integrated Lightning Flash Extent  

NASA Technical Reports Server (NTRS)

The objective of this preliminary study is to investigate the kinematic and microphysical control of lightning properties, particularly those that may govern the production of nitrogen oxides (NOx) in thunderstorms, such as flash rate, type and extent. The mixed-phase region is where the noninductive charging (NIC) process is thought to generate most storm electrification during rebounding collisions between ice particles in the presence of supercooled water. As a result, prior radar-based studies have demonstrated that lightning flash rate is well correlated to kinematic and microphysical properties in the mixed-phase region of thunderstorms such as updraft volume, graupel mass, or ice mass flux. There is also some evidence that lightning type is associated with the convective state. Intracloud (IC) lightning tends to dominate during the updraft accumulation of precipitation ice mass while cloud-to-ground (CG) lightning is more numerous during the downdraft-driven descent of radar echo associated with graupel and hail. More study is required to generalize these relationships, especially regarding lightning type, in a wide variety of storm modes and meteorological conditions. Less is known about the co-evolving relationship between storm kinematics, microphysics, morphology and three-dimensional flash extent, despite its importance for lightning NOx production. To address this conceptual gap, the NASA MSFC Lightning Nitrogen Oxides Model (LNOM) is applied to North Alabama Lightning Mapping Array (NALMA) and Vaisala National Lightning Detection NetworkTM (NLDN) observations following ordinary convective cells through their lifecycle. LNOM provides estimates of flash type, channel length distributions, lightning segment altitude distributions (SADs) and lightning NOx production profiles. For this study, LNOM is applied in a Lagrangian sense to well isolated convective cells on 3 April 2007 (single cell and multi-cell hailstorm, non-severe multicell) and 6 July 2007 (non-severe multi-cell) over Northern Alabama. The LNOM lightning characteristics are compared to the evolution of updraft and precipitation properties inferred from dual-Doppler and polarimetric radar analyses applied to observations from a nearby Doppler radar network, including the UA Huntsville Advanced Radar for Meteorological and Operational Research (ARMOR, C-band, polarimetric). The LNOM estimated SAD and lightning NOx production profiles are placed in the context of radar derived profiles of vertical motion, precipitation types and amounts. Finally, these analyses are used to determine if storm integrated flash channel extent is as well correlated to volumetric updraft and precipitation ice characteristics in the mixed phase region as flash rate for these individual convective cells.

Carey, Lawrence; Koshak, William; Petersen, Harold; Schultz, Elise; Schultz, Chris; Matthee, Retha; Bain, Lamont

2012-01-01

402

Structure and evolution of a midwestern storm during VORTEX-95 as determined from airborne Doppler data  

NASA Astrophysics Data System (ADS)

A midwestern squall line which occurred on 2 June 1995 near the border of New Mexico and Texas was observed and sampled by NWS WSR-88D and two airborne radars, namely, NOAA P-3 Lower Fuselage Radar and NCAR ELDORA. Within a four-hour time span, the squall line initially formed from a convective cell close to a surface dryline, through the subsequent ``secondary development'' and merging processes, these storms eventually organized into a squall line moving toward the east. Interestingly, cells within the squall line posses their major convective activities at the western end of the storm body. This structural feature together with the three-dimensional characteristics of each cell within the line are different from those observed in a traditional quasi two-dimensional squall line in the Mid-west. Our findings reveal that the presence of a larger directional and speed shear in the lower troposphere, due to the approaching mid-tropospheric large-scale short wave, played a key role in the formation and development of this convective system being investigated. The environmental conditions and storm evolution agree well with those reported in the previous numerical simulation studies using a cloud model. These numerical studies consistently showed that the combined effects of large- scale low-level wind shear and atmospheric thermal instability (i.e., a bulk Richardson number) uniquely determine the structure and evolution of a midwestern mesoscale convective system, such as a squall line. A dual-Doppler synthesis was conducted to study some structural features of two individual cells, embedded within the squall line, using ELDORA data. The differences between this line structure and the traditional squall line are identified and explained. With the aid of ELDORA high resolution data set, a detailed three-dimensional wind field was derived at every analysis level. The thermodynamic retrieval method was then employed to recover the pressure field from the detailed wind field. Subsequently, the derived wind and pressure fields were used to investigate the kinematic and dynamic structures of a mid-level mesocyclone associated with one of the storms embedded within the three-dimensional squall line.

Pan, Da-Gang

403

The Kinematic and Microphysical Control of Storm Integrated Lightning Flash Extent  

NASA Astrophysics Data System (ADS)

The objective of this preliminary study is to investigate the kinematic and microphysical control of lightning properties, particularly those that may govern the production of nitrogen oxides (NOx) in thunderstorms, such as flash rate, type and extent. The mixed-phase region is where the noninductive charging (NIC) process is thought to generate most storm electrification during rebounding collisions between ice particles in the presence of supercooled water. As a result, prior radar-based studies have demonstrated that lightning flash rate is well correlated to kinematic and microphysical properties in the mixed-phase region of thunderstorms such as updraft volume, graupel mass, or ice mass flux. There is also some evidence that lightning type is associated with the convective state. Intracloud (IC) lightning tends to dominate during the updraft accumulation of precipitation ice mass while cloud-to-ground (CG) lightning is more numerous during the downdraft-driven descent of radar echo associated with graupel and hail. More study is required to generalize these relationships, especially regarding lightning type, in a wide variety of storm modes and meteorological conditions. Less is known about the co-evolving relationship between storm kinematics, microphysics, morphology and three-dimensional flash extent, despite its importance for lightning NOx production. To address this conceptual gap, the NASA MSFC Lightning Nitrogen Oxides Model (LNOM) is applied to North Alabama Lightning Mapping Array (NALMA) and Vaisala National Lightning Detection NetworkTM (NLDN) observations following ordinary convective cells through their lifecycle. LNOM provides estimates of flash type, channel length distributions, lightning segment altitude distributions (SADs) and lightning NOx production profiles. For this study, LNOM is applied in a Lagrangian sense to well isolated convective cells on 3 April 2007 (single cell and multi-cell hailstorm, non-severe multi-cell) and 6 July 2007 (non-severe multi-cell) over Northern Alabama. The LNOM lightning characteristics are compared to the evolution of updraft and precipitation properties inferred from dual-Doppler and polarimetric radar analyses applied to observations from a nearby Doppler radar network, including the UAHuntsville Advanced Radar for Meteorological and Operational Research (ARMOR, C-band, polarimetric). The LNOM estimated SAD and lightning NOx production profiles are placed in the context of radar derived profiles of vertical motion, precipitation types and amounts. Finally, these analyses are used to determine if storm integrated flash channel extent is as well correlated to volumetric updraft and precipitation ice characteristics in the mixed phase region as flash rate for these individual convective cells.

Carey, L. D.; Koshak, W. J.; Peterson, H. S.; Schultz, E. V.; Matthee, R.; Schultz, C. J.; Petersen, W. A.; Bain, L.

2012-12-01

404

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

405

Interaction of Moist Convection With Jupiter's Zonal Jets  

NASA Astrophysics Data System (ADS)

Since Voyager times, observations have suggested that Jupiter's zonal jets violate the barotropic stability criterion (BSTC) (Ingersoll et al., 1981; Limaye, 1986; Li et al., in press). Recently, images from the Cassini Imaging Science System (ISS) (Porco et al., 2003; Li et al., in press) and from the Galileo imaging system (Little et al., 1999; Gierasch et al., 2000) have revealed important features of moist convection on Jupiter and suggest that moist convection may be driving the zonal jets. Here we investigate the interaction of moist convection with the zonal jets in a reduced-gravity quasi-geostrophic model using a moist convection parameterization that is based on the new observations. Our study shows that moist convection can excite multiple jets when the velocity of the flow in the deep underlying layer is zero, but these jets never violate the BSTC. However, based on a model of the interaction between the magnetic field and the zonal flow, Liu and Stevenson (2003, DPS 35th meeting) predict that there are easterly flows in the deep underlying layer at middle latitudes. With easterly flows in the deep underlying layer we can get stable multiple jets that violate the BSTC. Furthermore, the modeled jets have almost same width and amplitude as the observed jets. An easterly flow in the lower layer provides a simple explanation for why the upper layer jets are stable even though they violate the BSTC. The model reproduces the tilted, chevron-shaped cloud features provided we assume that the clouds persist longer than the moist convective storms that produce them.

Li, L.; Ingersoll, A. P.; Huang, X.

2004-12-01

406

Cyclone Gonu storm surge in Oman  

NASA Astrophysics Data System (ADS)

Super Cyclone Gonu is the strongest tropical cyclone on record in the Arabian Sea. Gonu caused coastal damage due to storm surge and storm wave impact as well as wadi flooding. High water marks, overland flow depths, and inundation distances were measured in the coastal flood zones along the Gulf of Oman from 1 to 4 August 2007. The high water marks peaked at Ras al-Hadd at the eastern tip of Oman exceeding 5 m. The storm surge of Gonu is modeled using the Advanced Circulation Model (ADCIRC). The multi-hazard aspect is analyzed by comparing observations from Cyclone Gonu with the 2004 Indian Ocean Tsunami.

Fritz, Hermann M.; Blount, Christopher D.; Albusaidi, Fawzi B.; Al-Harthy, Ahmed Hamoud Mohammed

2010-01-01

407

Geomagnetic storm fields near a synchronous satellite.  

NASA Technical Reports Server (NTRS)

An apparent early recovery of the main phase of geomagnetic storms at the distance of the synchronous satellite is examined in terms of changing electric current distributions in the magnetosphere during magnetic storms. It is suggested that a rapid recession of the edge of the plasma sheet (after the advance toward the earth during an early epoch of the main phase) is partly responsible for the early recovery. Relevant plasma sheet variations during geomagnetic storms are found to be in agreement with the inferred variations.

Kawasaki, K.; Akasofu, S. I.

1971-01-01

408

Magnetic Storms from the Ground: Teacher's Guide  

NSDL National Science Digital Library

In this activity, students will analyze graphical data to familiarize themselves with the Earth's changing magnetic field. They will discover that coronal mass ejections (CMEs) and other solar storms can buffet the Earth with clouds of charged particles and magnetic fields which will affect the large-scale properties of the Earth's magnetic field and can also be easily detected on the ground. During this activity students will become familiar with the Earth's changing magnetic field through a solar storm plotting activity, analyze graphical data to calculate the percent of change, and plot their information on a map of Canada to determine the areas that are the most susceptible to magnetic storms.

409

Granular Convection in Microgravity  

E-print Network

We investigate the role of gravity on convection in a dense granular shear flow. Using a microgravity modified Taylor-Couette shear cell under the conditions of parabolic flight microgravity, we demonstrate experimentally that secondary, convective-like flows in a sheared granular material are close to zero in microgravity and enhanced under high-gravity conditions, though the primary flow fields are unaffected by gravity. We suggest that gravity tunes the frictional particle-particle and particle-wall interactions, which have been proposed to drive the secondary flow. In addition, the degree of plastic deformation increases with increasing gravitational forces, supporting the notion that friction is the ultimate cause.

N. Murdoch; B. Rozitis; K. Nordstrom; S. F. Green; P. Michel; T. -L. de Lophem; W. Losert

2013-06-07

410

Granular Convection in Microgravity  

E-print Network

We investigate the role of gravity on convection in a dense granular shear flow. Using a microgravity modified Taylor-Couette shear cell under the conditions of parabolic flight microgravity, we demonstrate experimentally that secondary, convective-like flows in a sheared granular material are close to zero in microgravity and enhanced under high-gravity conditions, though the primary flow fields are unaffected by gravity. We suggest that gravity tunes the frictional particle-particle and particle-wall interactions, which have been proposed to drive the secondary flow. In addition, the degree of plastic deformation increases with increasing gravitational forces, supporting the notion that friction is the ultimate cause.

Murdoch, N; Nordstrom, K; Green, S F; Michel, P; de Lophem, T -L; Losert, W

2013-01-01

411

Magnetospheric convection at Uranus  

NASA Technical Reports Server (NTRS)

The unusual configuration of the Uranian magnetosphere leads to differences in the relative effects of solar wind induced magnetospheric convection and plasma corotation from those at the other planets. At the present epoch the orientation of the rotation axis of Uranus with respect to the solar wind flow direction leads to a decoupling of the convective and corotational flows, allowing plasma from the tail to move unimpeded through the inner magnetosphere. As Uranus progresses in its orbit around the sun, corotation plays a gradually more important role and the plasma residence times within the magnetosphere increase. When the rotation axis finally becomes perpendicular to the solar wind flow, corotation is dominant.

Selesnick, R. S.

1987-01-01

412

Comparison of auroral latitude convection to central polar cap convection. (Invited)  

NASA Astrophysics Data System (ADS)

The SuperDARN radar at McMurdo station has been providing convection observations in the central polar cap since January 2010. The Antarctic magnetic pole lies in the center of the radar field of view at about 1000 km range, which is optimum for convection observations. A new pair of SuperDARN radars was constructed in the Antarctic summer of 2012/2013, which add highly complimentary fields of view. The radars, one located at the Italian station at Dome-C, and one located at the US South Pole Station, are directed into a region directly equatorward of the McMurdo field of view. The radars came on line in late January 2013 and are producing excellent convection observations. This paper presents initial results combining the three radar's convection observations. Intervals when the IMF clock angle was between 135 and 225 for periods of more than an hour were selected for study. Just under 50 hours of observations met this criteria since the radars began operation. Convection vectors were formed using the standard SuperDARN algorithm [Ruohoniemi and Baker, 1998] and the auroral-zone flows were compared to those in the central polar cap. Central polar cap flows are typically spatially uniform though highly variable in time, even though the lower latitude observations were spatially structured. The central polar cap average flow velocity is less than 500 m/s, though it often exceeds 1000 m/s. Conditions that lead to the high-speed flow are presented. In addition, correlation with the IMF and solar wind are presented. At times the correlation exceeds 80% while at others it is near zero.

Bristow, W. A.; Amata, E.

2013-12-01

413

Combined buoyancy-thermocapillary convection  

NASA Technical Reports Server (NTRS)

Combined buoyancy-thermocapillary convection was studied in 2D and 3D. Fluid motion caused by thermally induced tension gradients on the free surface of a fluid is termed thermocapillary convection. It is well-known that in containerless processing of materials in space, thermocapillary convection is a dominant mechanism of fluid flow. Welding and crystal growth processes are terrestrial applications where thermocapillary convection has direct relevance.

Homsy, G. M.

1990-01-01

414

Building Enrollment in Summer Programs.  

ERIC Educational Resources Information Center

Presents suggestions from 17 day-care center directors on ways to improve summer enrollment. Suggestions include marketing summer programs early; offering reasonable fees, with reduced fees for low-income families; organizing new or different summer programs; creating a summer camp atmosphere; offering short-term summer programs; and including…

Child Care Information Exchange, 1994

1994-01-01

415

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

NASA Astrophysics Data System (ADS)

A comparison of the stable-isotope signatures of spring waters, snow, snowmelt, summer (July thru September) rain, and cool season (October thru June) rain indicates that the high-intensity, short-duration summer convective storms, which contribute approximately a third of the annual precipitation to the Spring Mountains, provide only a small fraction (perhaps 10%) of the recharge to this major upland in southern Nevada, USA. Late spring snowmelt is the principal means of recharging the fractured Paleozoic-age carbonate rocks comprising the central and highest portion of the Spring Mountains. Daily discharge measurements at Peak Spring Canyon Creek during the period 1978-94 show that snowpacks were greatly enhanced during El Niño events. Résumé La comparaison des signatures isotopiques stables des eaux de sources, de neige, de fonte de neige, des pluies d'été (juillet à septembre) et de saison froide (octobre à juin) montre que les précipitations convectives d'été de forte intensité et de courte durée, apportant un tiers des précipitations annuelles reçues par les Monts Spring, ne participent que pour une faible part (10%) à la recharge de cette importante zone d'altitude du sud du Nevada (États-Unis). La fonte tardive de la neige au printemps constitue l'essentiel de la recharge des roches carbonatées fracturées d'âge paléozoïque formant la partie centrale et la plus haute des Monts Spring. Les données journalières de débit sur la rivière du canyon de Peak Spring, entre 1978 et 1994, montrent que les hauteurs de neige ont été plus élevées pendant les événements El Niño. Resumen La comparación entre las marcas isotópicas de aguas de manantiales, nieve, deshielo, lluvias de verano (julio a septiembre) y resto de lluvias (octubre a junio) indican que las tormentas de verano, de corta duración y gran intensidad, las cuales suponen alrededor de un tercio de la precipitación total anual en las Spring Mountains, proporcionan sólo una fracción pequeña (alrededor del 10%) de la recarga en esta zona al sur de Nevada (EE.UU.). El deshielo de finales de la primavera es la principal fuente de recarga de las rocas carbonatadas fracturadas de edad Paleozoica que forman las partes central y superior de las Spring Mountains. Las medidas de descarga diarias en el Desfiladero de Peak Spring Canyon durante 1978-94 muestran que los espesores de nieve aumentaron coincidiendo con los fenómenos de El Niño.

Winograd, Isaac J.; Riggs, Alan C.; Coplen, Tyler B.

416

Sustainable Development Summer Intern Report 2013 Sustainable Development Summer Intern  

E-print Network

Sustainable Development Summer Intern Report 2013 Sustainable Development Summer Intern Final amongst university's invested in sustainable development. Our small but mighty size allows us to build through positive sustainable practices. As the Sustainable Development Summer Intern I am fortunate enough

417

ARROYO VISTA /CAMPUS VILLAGE SUMMER SESSION HOUSING CANCELLATION OF CONTRACT Summer Session I Summer Session II Full Summer (Freshman or Transfer) Summer Start  

E-print Network

ARROYO VISTA /CAMPUS VILLAGE SUMMER SESSION HOUSING CANCELLATION OF CONTRACT Summer Session I Summer Session II Full Summer (Freshman or Transfer) Summer Start NAME: STUDENT ID NUMBER: Last (Family your Arroyo Vista or Campus Village Summer housing contract. You will be contacted by Student Housing

Loudon, Catherine

418

Ionospheric storm effects at subauroral latitudes - A case study  

NASA Technical Reports Server (NTRS)

An attempt is made to classify ionospheric storm effects at subauroral latitudes according to their presumed origin. The storm of December 7/8, 1982, serves as an example. It is investigated using ionosonde, electron content, and DE 2 satellite data. The following effects are distinguished: (1) positive storm effects caused by traveling atmospheric disturbances, (2) positive storm effects caused by changes in the large-scale thermospheric wind circulation, (3) positive storm effects caused by the expansion of the polar ionization enhancement, (4) negative storm effects caused by perturbations of the neutral gas composition, and (5) negative storm effects caused by the equatorward displacement of the trough region.

Proelss, G. W.; Brace, L. H.; Mayr, H. G.; Carignan, G. R.; Killeen, T. L.

1991-01-01

419

Convective Systems Over the South China Sea: Cloud-Resolving Model Simulations  

NASA Technical Reports Server (NTRS)

The South China Sea Monsoon Experiment (SCSMEX) was conducted in May-June 1998. One of its major objectives is to better understand the key physical processes for the onset and evolution of the summer monsoon over Southeast Asia and southern China. Multiple observation platforms (e.g., upper-air soundings, Doppler radar, ships, wind profilers, radiometers, etc.) during SCSMEX provided a first attempt at investigating the detailed characteristics of convective storms and air pattern changes associated with monsoons over the South China Sea region. SCSMEX also provided rainfall estimates which allows for comparisons with those obtained from the Tropical Rainfall Measuring Mission (TRMM), a low earth orbit satellite designed to measure rainfall from space. The Goddard Cumulus Ensemble (GCE) model (with 1-km grid size) is used to understand and quantify the precipitation processes associated with the summer monsoon over the South China Sea. This is the first (loud-resolving model used to simulate precipitation processes in this particular region. The GCE-model results captured many of the observed precipitation characteristics because it used a fine grid size. For example, the temporal variation of the simulated rainfall compares quite well to the sounding-estimated rainfall variation. The time and domain-averaged temperature (heating/cooling) and water vapor (drying/ moistening) budgets are in good agreement with observations. The GCE-model-simulated rainfall amount also agrees well with TRMM rainfall data. The results show there is more evaporation from the ocean surface prior to the onset of the monsoon than after the on-et of monsoon when rainfall increases. Forcing due to net radiation (solar heating minus longwave cooling) is responsible for about 25% of the precipitation in SCSMEX The transfer of heat from the ocean into the atmosphere does not contribute significantly to the rainfall in SCSMEX. Model sensitivity tests indicated that total rain production is reduced 17-18% in runs neglecting the ice phase. The SCSMEX results are compared to other GCE-model-simulated weather systems that developed during other field campaigns (i.e., west Pacific warm pool region, eastern Atlantic region and central USA). Large-scale forcing vie temperature and water vapor tendency, is the major energy source for net condensation in the tropical cases. The effects of large-scale cooling exceed that of large-scale moistening in the west pacific warm pool region and eastern Atlantic region. For SCSMEX, however, the effects of large-scale moistening predominate. Net radiation and sensible and latent hc,it fluxes play a much more important role in the central USA.

Tao, Wei-Kuo; Shie, C.-L.; Johnson, D.; Simpson, J.; Braun, S.; Johnson, R.; Ciesielski, P. E.; Starr, David OC. (Technical Monitor)

2002-01-01

420

High-resolution simulations of convective cold pools over the northwestern Sahara  

Microsoft Academic Search

Cooling by evaporation of convective precipitation in the deep and dry subcloud layer over desert regions can generate intense downdrafts and long-lived and extensive atmospheric density currents. The strong gusts at their leading edges can cause so-called haboob dust storms. Despite their importance for the dust cycle, the ability of state-of-the-art numerical weather prediction models to realistically simulate the associated

P. Knippertz; J. Trentmann; A. Seifert

2009-01-01

421

Field Evaluation of Low-E Storm Windows  

SciTech Connect

A field evaluation comparing the performance of low emittance (low-e) storm windows with both standard clear storm windows and no storm windows was performed in a cold climate. Six homes with single-pane windows were monitored over the period of one heating season. The homes were monitored with no storm windows and with new storm windows. The storm windows installed on four of the six homes included a hard coat, pyrolitic, low-e coating while the storm windows for the other two homeshad traditional clear glass. Overall heating load reduction due to the storm windows was 13percent with the clear glass and 21percent with the low-e windows. Simple paybacks for the addition of the storm windows were 10 years for the clear glass and 4.5 years forthe low-e storm windows.

Drumheller, S. Craig; Kohler, Christian; Minen, Stefanie

2007-07-11

422

Geomagnetic storms, super-storms, and their impacts on GPS-based navigation systems  

NASA Astrophysics Data System (ADS)

data of GPS receivers located worldwide, we analyze the quality of GPS performance during four geomagnetic storms of different intensity: two super-storms and two intense storms. We show that during super-storms the density of GPS Losses-of-Lock (LoL) increases up to 0.25% at L1 frequency and up to 3% at L2 frequency, and up to 0.15% (at L1) and 1% (at L2) during less intense storms. Also, depending on the intensity of the storm time ionospheric disturbances, the total number of total electron content (TEC) slips can exceed from 4 to 40 times the quiet time level. Both GPS LoL and TEC slips occur during abrupt changes of SYM-H index of geomagnetic activity, i.e., during the main phase of geomagnetic storms and during development of ionospheric storms. The main contribution in the total number of GPS LoL was found to be done by GPS sites located at low and high latitudes, whereas the area of numerous TEC slips seemed to mostly correspond to the boundary of the auroral oval, i.e., region with intensive ionospheric irregularities. Our global maps of TEC slips show where the regions with intense irregularities of electron density occur during geomagnetic storms and will let us in future predict appearance of GPS errors for geomagnetically disturbed conditions.

Astafyeva, E.; Yasyukevich, Yu.; Maksikov, A.; Zhivetiev, I.

2014-07-01

423

Science in the Summer.  

ERIC Educational Resources Information Center

Describes a summer program called Science in the Summer (SitS). The goal of this 9-year program is to encourage students to engage in science learning. Presents beginner and advanced level activities focusing on chemistry and engineering. Summarizes student evaluations on the program along with a breakdown of the SitS 1999 program. (SAH)

Redmond, Alan

2000-01-01

424

Celebrate Summer with Reading  

ERIC Educational Resources Information Center

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…

Texley, Juliana

2007-01-01

425

Book Your Summer Vacation  

ERIC Educational Resources Information Center

Summer's the time for teachers to travel, not only physically from the confines of the classroom to exotic places, but vicariously, through the magic of books. Summer adventures help teachers expand their experience and enrich their store of context so that they can offer their students more when school resumes in the fall. That's why each year…

Texley, Juliana

2012-01-01

426

Pontotoc County Government Summer  

E-print Network

Pontotoc County Government Summer Youth Internship Program June 17 - 21, 2013 Sponsored By Government Summer Youth Internship Program June 17-21, 2013 Who: Youth ages 14-19 who attend a Pontotoc 24, 2013. What: Learn About YOUR Pontotoc County Government. Youth will spend time in each

Balasundaram, Balabhaskar "Baski"

427

SUMMER SEMESTER (3 credits)  

E-print Network

SUMMER SEMESTER (3 credits) General Education Courses: Credit Hours: General Education Courses: Credit Hours: General Education Course: ENGL 110C 3 ENGL 211C, or 221C or 231C 3 Foreign Language I (may 3 SUMMER SEMESTER (3 credits) General Education Courses: Credit Hours: General Education Courses

428

Under Summer Skies  

ERIC Educational Resources Information Center

There's 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. There's no better place to start your summer reading than under their influence. Here are a few selections identified by…

Texley, Juliana

2009-01-01

429

Intramural Sports Summer 2014  

E-print Network

Handbook. Insurance The Department of Recreational Sports does not provide health or accident insuranceIntramural Sports 4v4 Soccer Tournament Summer 2014 Intramural Sports Calendar of Events Summer 2014 Potential League Offerings Men's Women's Co-Rec Sports and Special Programs Office 111 Dixon

Escher, Christine

430

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

431

Summer Family Memberships  

E-print Network

Association Members $270 Community $295 Teen Summer Pass (13-17 year olds) Applies when a teen enters without teen for the membership and sign waiver of liability. Parent or guardian need NOT be a member to purchase a teen summer pass. $65 Adult Day Pass - $12, Child Day Pass - $6, Teen Day Pass - $7 Parent

California at Santa Barbara, University of

432

Summer Undergraduate Research Fellowships  

E-print Network

CCOM-SURF Summer Undergraduate Research Fellowships Center for Coastal & Ocean Mapping University and for training the next generation of ocean mappers. CCOM's Summer Undergraduate Research Fellowship (SURF) program is designed to create research experi- ences for undergraduate students who are interested

New Hampshire, University of

433

Your Best Summer Ever  

ERIC Educational Resources Information Center

"It must be nice to have summers off." Only other teachers know just how short summer is, with much of August devoted to planning for the new school year. This article offers 17 fresh ideas for exploring, making money, and preparing for next year. Plus, a reading list that hits all the marks!

Cleaver, Samantha

2012-01-01

434

[Summary of Research on Relationship Between Core Convective Structure and Intensity Change in Tropical Cyclones  

NASA Technical Reports Server (NTRS)

The downshear reformation of Tropical Storm Gabrielle (2001) was investigated using radar reflectivity and lightning data that were nearly continuous in time, as well as frequent aircraft reconnaissance flights. Initially the storm was a marginal tropical storm in an environment with strong 850-200 hPa vertical wind shear of 12-13 meters per second and an approaching upper tropospheric trough. Both the observed outflow and an adiabatic balance model calculation showed that the radial-vertical circulation increased with time as the trough approached. Convection was highly asymmetric, with almost all radar return located in one quadrant left of downshear in the storm. Reconnaissance data show that an intense mesovortex formed downshear of the original center. This vortex was located just south of, rather than within, a strong downshear left lightning outbreak, consistent with tilting of the horizontal vorticity associated with the vertical wind shear. The downshear mesovortex contained a 972 hPa minimum central pressure, 20 hPa lower than minimum pressure in the original vortex just three hours earlier. The mesovortex became the new center of the storm, but weakened somewhat prior to landfall. It is argued that dry air carried around the storm from the region of upshear subsidence, as well as the direct effects of the shear, prevented the reformed vortex from continuing to intensify. Despite the subsequent weakening of the reformed center, it reached land with greater intensity than the original center. It is argued that this intensification process was set into motion by the vertical wind shear in the presence of an environment with upward motion forced by the upper tropospheric trough. In addition, the new center formed much closer to the coast and made landfall much earlier than predicted. Such vertical shear-induced intensity and track fluctuations are important to understand, especially in storms approaching the coast. The structures of the highly sheared tropical storm Chantal During CAMEX-4 is also discussed.

2005-01-01

435

Winter and summer simulations with the GLAS climate model  

NASA Technical Reports Server (NTRS)

The GLAS climate model is a general circulation model based on the primitive equations in sigma coordinates on a global domain in the presence of orography. The model incorporates parameterizations of the effects of radiation, convection, large scale latent heat release, turbulent and boundary layer fluxes, and ground hydrology. Winter and summer simulations were carried out with this model, and the resulting data are compared to observations.

Shukla, J.; Straus, D.; Randall, D.; Sud, Y.; Marx, L.

1981-01-01

436

CME Link to the Geomagnetic Storms  

NASA Technical Reports Server (NTRS)

The coronal mass ejection (CME) link to geomagnetic storms stems from the southward component of the interplanetary magnetic field contained in the CME flux ropes and in the sheath between the flux rope and the CME-driven shock. A typical storm-causing CME is characterized by (i) high speed, (ii) large angular width (mostly halos and partial halos), and (iii)solar source location close to the central meridian. For CMEs originating at larger central meridian distances, the storms are mainly caused by the sheath field. Both the magnetic and energy contents of the storm-producing CMEs can be traced to the magnetic structure of active regions and the free energy stored in them.

Gopalswamy, Nat

2009-01-01

437

46 CFR 108.221 - Storm rails.  

Code of Federal Regulations, 2010 CFR

...108.221 Section 108.221 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) A-MOBILE OFFSHORE DRILLING UNITS DESIGN AND EQUIPMENT Construction and Arrangement Rails § 108.221 Storm rails. Each unit...

2010-10-01

438

Tropical Storm Don - Duration: 0:31.  

NASA Video Gallery

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

439

Dealing with Storm-Damaged Trees  

E-print Network

Many homeowners need help caring for or removing damaged trees after a natural disaster. This publication explains what a certified arborist is and how to select one. It also cautions against burning debris downed by a storm....

Kirk, Melanie; Taylor, Eric; Foster, C. Darwin

2005-10-25

440

Coastal Change Hazards: Hurricanes and Extreme Storms  

MedlinePLUS

... at the surface to continue to fall. Resulting winds blow in towards the low-pressure center and, ... a counter-clockwise fashion forming the familiar cyclonic wind pattern of a hurricane. A storm system is ...