Дисертації з теми "Mesoscale convective cloud systems"
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Mechem, David B. "Organized layer overturning in mesoscale convective systems over the western Pacific warm pool /." Thesis, Connect to this title online; UW restricted, 2003. http://hdl.handle.net/1773/10059.
Повний текст джерелаWhite, Bethan Alice. "Modelling of elevated mesoscale convective systems." Thesis, University of Leeds, 2012. http://etheses.whiterose.ac.uk/3151/.
Повний текст джерелаCoutris, Pierre. "Analyse des propriétés dimensionnelles et massiques des cristaux de glace pour l’étude des processus microphysiques dans les systèmes convectifs à méso-échelle." Thesis, Université Clermont Auvergne (2017-2020), 2019. http://www.theses.fr/2019CLFAC007/document.
Повний текст джерелаThe detailed characterization of ice cloud microphysics is key to understand their role in theEarth’s hydrological cycle and radiation budget. The developement of atmospheric models and remote sensingalgorithms relies on parametrisations derived from in situ measurements. These measurements are also usedby the aviation industry to handle the problem of ice crystal icing. This PhD work presents an analysis of themass and size properties of ice crystals observed in high ice water content areas embedded in tropical mesoscaleconvective systems (MCS) during two airborne field campaigns of the HAIC-HIWC international project.A new approach is developped to derive mass-size relationships (m - D) from size distributions and icewater contents. The retrieval is formulated as an inverse problem which waives the power law constraint, aclassical assumption that proves to be an oversimplification when applied to heterogeneous populations of iceparticules typical of MCS anvils.The horizontal variability of size distributions and the aging of MCS anvils is described in terms of microphysicalprocesses. The importance of the aggregation growth process is emphasized as it efficiently removessmall ice particles brought into the upper troposphere by deep convection and significantly contributes to theformation of large agregates, precusor of the stratiform precipitations. The analysis of mass properties revealsthat distinctive microphysical regimes may be identified from the m-D relationship retrieved in various conditions.It paves the way toward a statistical model of the effective density of ice particles as a function of environmentalparameters
Correia, James. "Observations and simulations of mesoscale convective systems." [Ames, Iowa : Iowa State University], 2007.
Знайти повний текст джерелаBister, Marja Helena. "Development of tropical cyclones from mesoscale convective systems." Thesis, Massachusetts Institute of Technology, 1996. http://hdl.handle.net/1721.1/57851.
Повний текст джерелаIncludes bibliographical references (p. 109-112).
by Marja Helena Bister.
Ph.D.
Mapes, Brian. "The Australian monsoon and its mesoscale convective systems /." Thesis, Connect to this title online; UW restricted, 1992. http://hdl.handle.net/1773/10068.
Повний текст джерелаFinta, Christopher A. "Observations of mesoscale convective systems during tropical cyclone genesis." Monterey, California. Naval Postgraduate School, 1997. http://hdl.handle.net/10945/8757.
Повний текст джерелаA better understanding of the role mesoscale convective systems (MCS) play in the formation stages of tropical cyclones will increase the ability to predict their occurrence and motion. This thesis employs high-resolution satellite imagery to observe the interaction between MCSs and their environment. Specifically, thirteen cases of tropical disturbances that eventually developed into tropical cyclones are analyzed to determine the role of MCSs in increasing the system organization. Following two conceptual models developed during the Tropical Cyclone Motion (TCM-93) mini-field experiment, each tropical cyclone is classified according to the relative importance of MCS activity to its development. Both conceptual models are verified through analysis and a third model is created to account for tropical cyclone developments that share features of the previous two models. An alternate approach is proposed for determining tropical system organization using only visible and infrared satellite imagery
Gray, M. E. B. "Geostrophic adjustment following deep convection." Thesis, University of Reading, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.318585.
Повний текст джерелаHoffmann, Alex. "Simulating organization of convective cloud fields and interactions with the surface." Thesis, University of Cambridge, 2013. https://www.repository.cam.ac.uk/handle/1810/245211.
Повний текст джерелаMilot, David. "Microwave observations of mesoscale convective systems during tropical cyclone genesis in the Western North Pacific." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 1998. http://handle.dtic.mil/100.2/ADA344670.
Повний текст джерела"March 1998." Thesis advisor(s): Russell L. Elsberry, Patrick A. Harr. Includes bibliographical references (p. 91-93). Also available online.
McKinley, Eric J. "An analysis of mesoscale convective systems observed during the 1992 tropical cyclone motion field experiment." Thesis, Monterey, California. Naval Postgraduate School, 1992. http://hdl.handle.net/10945/23531.
Повний текст джерелаClarke, Smantha. "Multi-scale and upscale interaction of mesoscale convective systems in the United Kingdom and France." Thesis, University of Reading, 2018. http://centaur.reading.ac.uk/77951/.
Повний текст джерелаHodapp, Charles Lee. "The evolution of total lightning and radar reflectivity characteristics of two mesoscale convective systems over Houston, Texas." Thesis, [College Station, Tex. : Texas A&M University, 2007. http://hdl.handle.net/1969.1/ETD-TAMU-2422.
Повний текст джерелаFerandez, Damacene V. "Incorporation and comparative evaluation of a non-convective cloud parameterization scheme in the Naval Research Laboratory West Coast mesoscale weather prediction model." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 1993. http://handle.dtic.mil/100.2/ADA272493.
Повний текст джерелаSakamoto, Meiry Sayuri. "Sistemas convectivos de mesoescala observados na Região Subtropical da América do Sul durante o SALLJEX." Universidade de São Paulo, 2009. http://www.teses.usp.br/teses/disponiveis/14/14133/tde-24052018-115441/.
Повний текст джерелаIn this study, we analyze continental and oceanic mesoscale convective systems (MCS\'s) observed in the subtropics of South America during the South American Low Level Experiment (SALLJEX), held in the summer of 2002/2003. This analysis evaluated the spatial distribution, diurnal variability, life cycle, displacement and morphological parameters of the continental and oceanic MCSs, and also investigated the origins of moisture sources that contribute to these systems genesis. Other issues considered are the characterization of the synoptic conditions and the identification of preconditioning and trigger mechanisms, and evaluation of dynamic and thermodynamic conditions observed during the convective system genesis and its evolution over the life cycle. Moreover, MCSs numerical simulations are made focused on the model capability to replicate the essential atmospheric conditions to the convection generation. The results show that the continental convective systems are more numerous than the oceanic ones, and in both regions, MCS\'s with longer duration have higher growth rates in the early hours of their life cycle. The low level jet (LLJ) affects the formation of the continental systems, but its effect on oceanic MCS\'s is minimal. The tropical Atlantic Ocean, the Amazon region and the subtropical Pacific Ocean, are the main moisture source to the genesis of convective systems, however, the incidence of these sources depends on the convective system genesis area and the synoptic conditions. The daytime heating of convective boundary layer, the low level jet, the trough at 500 hPa and transverse circulation are the preconditioning processes identified in the formation of nocturnal MCS\'s with continental origin. For trigger mechanisms, the main factors are the frontal systems and the katabatic flow from the Andes Mountain. Convective systems with longer life cycles are generated in an environment in which several preconditioning and trigger mechanisms act jointly. Moreover, the vertical wind shear at low levels appears to be one of the differences in the initial phase of long living MCSs. The results of numerical simulations suggest that when the characteristics of synoptic and mesoscale that act as pre-conditions or triggering mechanisms are better defined, the model\'s performance improves significantly, because the simulation can more accurately reproduce the environmental conditions observed during the genesis of the convective system. Thus, systems with longer duration tend to be better simulated.
Rehbein, Amanda. "Sistemas convectivos de mesoescala observados na bacia Amazônica durante o projeto GOAmazon." Universidade de São Paulo, 2016. http://www.teses.usp.br/teses/disponiveis/14/14133/tde-29052018-102758/.
Повний текст джерелаIn the present study, we analyzed the continental and oceanic mesoscale convective systems (MCSs) that occurred over the Amazon Basin, during one year and six months of Green Ocean Amazon Project (GOAmazon). The analysis included the spatial distribution, diurnal variability, lifecycle, displacement and morphological parameters of the MCSs. A climatology using 14 years data was developed to compare the results obtained during the GOAmazon. A synoptic, thermodynamic and dynamic analysis was made for 21 MCSs that occurred next to the GOAmazon data collection sites. The climatology results show 7053 continental MCSs occurring along the year. In 2014, the occurrence was 56.3% of that value and during the period analyzed in 2015 it was 58%. The MCSs occurred during the GOAmazon also presented shorter lifecycles, displacements and speeds compared to climatology. The lifetime evolution of short lived and long lived MCSs present few hours of difference between the same phase. The time from genesis to maturation phase of short lived systems is 2 to 3 hours and for those long lived the time is 3 to 4 hours. The mean speed, direction and displacement are greater during the winter. The average density reveal preferential regions of genesis. They are: 1) downstream Andes Mountain, among 10ºS and 20ºS/70ºW and 75ºW; 2) confluence of Amazon and Tapajós Rivers, near to 2.5ºS/54ºW; 3) Pacaraima Mountains at Guyana Shield, in approximately 5ºN/60ºW; 4) Imeri Mountains at Guyana Shield, in 0º/65ºW and; 5) between north of Mato Grosso state and south of Pará state, around 10ºS/55ºW. During the GOAmazon the negative density anomalies occurred spread along the Amazon Basin, with some points of greater occurrence. The oceanic MCSs occurred preferentially in the winter season in the northeast of Amazon Basin. Their frequency of occurrence is fewer than continental, in average four MCSs per month. Nevertheless, they have large areas during their maturation phase, longer lifecycles and displacements. Most of them have genesis next to the land and their development is over the Amazon Basin. During GOAmazon their occurrence was fewer than the climatology and the features were different. The analysis for the 21 cases in which MCSs occurred next to GOAmazon stations showed that a combination of trade winds driven to Amazon Basin and frontal systems close to Tropical region were important for keeping the long lived MCSs. During occurrence of large area systems, the wind shear was greater than during other events. In most of 2014 and 2015, anomalous patterns in the atmospheric circulation, triggered by anomalous sea surface temperature in the Equatorial Pacific Ocean, occurred and this may justify the fewer occurrence of MCSs, lifecycle and displacement in that period. From our knowledge of the literature, this is the first work that makes an annual climatological analysis of MCSs occurrence through high temporal and spatial data and very few missing data using a geographical delimitation of Amazon basin. That is, considering only the MCSs that in one moment of their lifecycle, at least, interact with the Amazon Basin.
Albrecht, Rachel Ifanger. "Eletrificação dos sistemas precipitantes na região Amazônica: processos físicos e dinâmicos do desenvolvimento de tempestades." Universidade de São Paulo, 2008. http://www.teses.usp.br/teses/disponiveis/14/14133/tde-24102008-154430/.
Повний текст джерелаAmazonian convective systems have unique microphysical characteristics, varying from a maritime convective behavior (rainy season) to a continental behavior (wet-dry transition season). These characteristics modulate the electrification of these systems, however it is still not well understood which are the dominant processes that intensify the frequency of lightning from one season to another: aerosol effect, thermodynamics, large-scale variability, landscape or topography? To answer this question, the objective of this study was to identify and quantify the importance of each one of these effects on the electrification of convective systems over the Amazon. The methodology was based on the analysis of observational data from the field experiment DRYTOWET and a numerical model with charge transfer parameterizations and lightning discharges. The cloud-to-ground (CG) lightning discharges annual cycle presented that the electrical activity of the southwestern Amazonian precipitating systems increased during the transition between the dry and wet seasons (August to September), in association with the convective systems deepening. With the establishment of the wet season (November to March), the number of CGs decreased but the electrical activity continued. The mean annual percentage of cloud-to-ground lightning of positive polarity (+CGs) was 12%, increasing drastically to 25% in September during the transition between the dry and wet seasons. This percentage of +CGs raise happened simultaneously with the increase in the atmospheric pollution due to the pasture biomass burning, held by local farmers to prepare the soil for agriculture and livestock during the begging of first rains. On the other hand, the increase in %+CGs also occurred preferentially over pasture areas of Rondonia state. Through the analysis of radar precipitating systems that occurred during the field campaign DRYTOWET, it was noted that positive thunderstorms (storms that produced more than 50% of +CGs over 50% of their life time) were initiated in drier and higher lift condensation levels (cloud base height) environments than other storms (negative thunderstorms) during all the field experiment, especially in the end of the dry season (September-October). A higher cloud base height is associated with a shallower warm cloud depth (cloud base height to the 0oC isotherm) and consequently less entrainment, increasing the updrafts due to a more efficient processing of the convective available potential energy (CAPE). This increase in updrafts inside the clouds results in deeper and stronger thunderstorms. The higher cloud base heights is a characteristic from pasture regions, where the ratio between sensible and latent heats at surface is greater than forested areas, which increases the top of the planetary boundary layer. The differences in the aerosol total concentration and size distribution, due to the increase in the atmospheric pollution during the transition between the dry and wet seasons, were inconclusive in a possible aerosol effect in the strength of positive and negative thunderstorms, once the aerosol concentration diurnal cycle follows the cycle of the planetary boundary layer, that also regulates the warm cloud depth effect. Numerical simulation of an 1D cloud model, coupled with charge transfer between the hydrometeors, showed that the thermodynamic structure was the main responsible feature for cloud electrification, increasing the updraft velocities. The pollution effect was masked in simulations, which inhibit the warm precipitation and consequently strength the the mixed and cold regions of the cloud, was responsible for an increase in the number of smaller aggregated particles, like snow flakes and graupel, decreasing the electrification and lightning frequency.
Eichholz, Cristiano Wickboldt, and Cristiano Wickboldt Eichholz. "Características físicas dos Sistemas Convectivos de Mesoescala que afetaram o Rio Grande do Sul no período de 2004 a 2008." Universidade Federal de Pelotas, 2011. http://repositorio.ufpel.edu.br/handle/ri/2201.
Повний текст джерелаThe happening of Mesoscale Convective Systems (MCS) over a region causes impacts on the surface, that is usually associated with heavy precipitation, strong wind gusts and hail. This phenomenon is common in southern Brazil reach the Rio Grande do Sul (RS) and causes damage to its economy. Therefore the MCS study that reaching of RS is of great importance, as well as allowing a greater understanding of weather and climate of the region also provide knowledge to decision makers. Thus, the aim was to study the seasonal physics features of MCS whose genesis and maintenance happened southward of 20 º S, with life cycle of at least 6 h, with spontaneous initiation and normal dissipation and that reached the region covering the RS from 2004 to 2008, using the FORTRACC method (Forecasting and Tracking of Active Cloud Clusters). Channel 4 Geostationary Operational Environmental Satellite (GOES) images from 2004/01/01 to 2008/12/31, with 4 km x 4 km spatial resolution in your subsatellite point and ½ hour temporal resolution were used. These images were provided by DSA/CPTEC/INPE (Satellite Division and Environmental Systems/Center for Weather Forecast and Climate Studies/National Institute for Space Research) and served as a database for the use of the FORTRACC method. The results showed that: i) the MCS that affected the RS occurring majority in the warmest quarter of the year (JFM), ii) in the four quarters of the study period most of the MCS that affected the RS (64.7%) had lifetime between 6 and 12 h, iii) MCS with longer life cover larger areas, and iv) the minimum temperature (Tir) had lower mean values observed in the MCS in OND and JFM, v) in all periods of the year around 6.4% of the MCS showed a more linear format, approximately 64.0% have irregular shape and about 29.6% had more circular shape, vi) lower values of Tir are related to MCS with shape close to circular (eccentricity equal to or greater than 0.5) and longer duration, vii) the three phases of the life cycle of MCS that affected the RS can occur in a distributed manner throughout the day, viii) in all periods of years the births of MCS that affected RS occur predominantly in and around the grill that covers the RS, with a tendency to start over on the west side of the grid on the mainland; ix) in all quarters there is a tendency for the mean trend preferential be from west to east.
A passagem de Sistemas Convectivos de Mesoescala (SCM) sobre uma região causa impactos em superfície, pois geralmente está associada à precipitação intensa, fortes rajadas de vento e granizo. Esse fenômeno bastante comum na região sul do Brasil afeta o Rio Grande do Sul (RS) e causa prejuízos a sua economia. Portanto o estudo dos SCM que atingem o RS é de grande importância, pois além de permitir um maior entendimento do tempo e do clima da região também fornece subsídios aos tomadores de decisão. Assim, o objetivo deste trabalho foi estudar as características físicas sazonais dos SCM cuja gênese e manutenção ocorreu ao sul de 20ºS, que apresentaram ciclo de vida de no mínimo 6 h, que tiveram nascimento espontâneo e dissipação normal e que afetaram a região que cobre o RS durante o período de 2004 a 2008, utilizando a técnica ForTrACC (Forecasting and Tracking of Active Cloud Clusters). Foram utilizadas as imagens brutas do satélite GOES (Geostationary Operational Environmental Satellite) do canal 4, com resolução espacial no seu ponto subsatelite de 4 km x 4 km e resolução temporal de ½ hora, do período de 01/01/2004 a 31/12/2008. Essas imagens foram fornecidas pela Divisão de Satélites Ambientais do Centro de Previsão de Tempo e Estudos Climáticos do Instituto Nacional de Pesquisas Espaciais (DSA/CPTEC/INPE) e serviram como base de dados para a utilização da técnica ForTrACC. Os resultados para o período de estudo mostraram que: i) os SCM que afetaram o RS apresentaram maior número de ocorrência no período mais quente do ano (JFM); ii) nos quatro trimestres do período de estudo a maioria dos SCM que afetou o RS (64,7%) apresentaram tempo de vida entre 6 e 12h; iii) SCM com maior tempo de vida cobrem áreas maiores; iv) a temperatura mínima (Tir) apresentou valores médios menores nos SCM observados em JFM e OND; v) em todos os períodos do ano em torno de 6,4% dos SCM apresentaram formato mais linear, aproximadamente 64,0% apresentaram formato irregular e em torno de 29,6% apresentaram formato mais circular; vi) valores menores de Tir estão relacionados à SCM com formato mais próximo do formato circular (excentricidade igual ou maior do que 0,5) e com maior duração; vii) as 3 fases do ciclo de vida dos SCM que afetaram o RS podem ocorrer de forma distribuída ao longo do dia; viii) em todos os períodos do ano os nascimentos dos SCM que afetaram o RS ocorrem predominantemente dentro e em torno da grade que cobre o RS, com tendência a iniciarem mais no lado oeste da grade sobre o continente; ix) em todos os trimestres há uma tendência de a trajetória média preferencial ser de oeste para leste.
Taufour, Marie. "Validation et amélioration du schéma microphysique à deux moments LIMA à partir des observations de la campagne de mesures HyMeX." Thesis, Toulouse 3, 2018. http://www.theses.fr/2018TOU30325/document.
Повний текст джерелаThe triggering and growth of Convective systems is a complex process that extends from the synoptic scale, with the establishment of atmospheric circulations promoting convection, to the microscale, with the formation and growth processes of hydrometeors. This PhD focuses on these finest scales and investigates the contribution of complex cloud-microphysics to the occurrence and morphology of heavy precipitation events. The two-moment microphysical scheme LIMA evaluated in this study takes into account the evolution of a multimodal aerosol population and the prognostic treatment of its interaction with liquid and ice clouds and precipitation. First, the contribution of LIMA is evaluated in comparison to the ICE3 one-moment bulk microphysical scheme, which is less sophisticated and currently operational in the AROME model at Météo-France. In order to measure the performance of this new scheme, two case studies of the HyMeX campaign were simulated with the Meso-NH model and compared to a wide variety of available measurements. The assessment of cumulative precipitation shows a moderate impact of each of these microphysical schemes, but the difference is more pronounced in terms of convective systems composition and structure: the two moment microphysics develops a more realistic vertical structure and introduces more microphysical variability. The evaluation also identified biases in the scheme (such as an overestimation of rain drop diameters). Some improvements to the implementation of LIMA were proposed and evaluated on the same cases. Then, the scheme is used to perform a sensitivity test to the aerosol population on the same case studies. Tests on the concentration of idealized populations have shown that aerosols do not only affect primary production of cloud droplets and ice crystals but also precipitating hydrometeors, causing impacts on the development of simulated convective systems in terms of cloud composition and generated precipitation. Simulations based on a realistic aerosol population initialized from CAMS analyses also showed a moderate impact on cumulative precipitation, but a more significant improvement on the temporal evolution of the system (intensification, dissipation) and cloud composition, leading to a reduction of rain drop diameters in the studied cases
Silva, Mirlen Tássia Filgueira da, and Mirlen Tássia Filgueira da Silva. "Estudo das Descargas Elétricas Atmosféricas associadas a sistemas convectivos de mesoescala para a Região Sudeste do Brasil." Universidade Federal de Pelotas, 2009. http://repositorio.ufpel.edu.br/handle/ri/2194.
Повний текст джерелаIn this work it is presented the study of 6 years of detected lightning data in association to the occurrence of mesoscale convective systems in the region located between 15ºS - 27ºS and 35ºW - 55ºW. The Lightning data were provided by FURNAS Centrais Elétricas S.A. for the period 2002-2007. Geostationary satellite images, enhanced in the infrared channel, were used to identify the cases of interest utilizing -50ºC as cloud top level temperature threshold for convective clusters. For these days, lightning detected in the study region should attain a minimum value of 1000 during 1 hour in some moment of occurrence during the identified cases. From the 565 days that satisfied this criterion, it was selected 25 cases occurred in 33 days during the years of 2003, 2005 (from October to December due to satellite images limitations), 2006 and 2007. For the period of occurrence of each one of these 25 cases, the detected lightning were counted during an interval of 15 minutes before and after the time of the satellite images used in each case to put in evidence the lightning associated to the observed convective clusters. The quantity of detected lightning in a convective cluster were related to its evolutive cycle.
Neste trabalho é apresentado o estudo de 6 anos de dados de descargas elétricas atmosféricas (DEA) detectadas em associação com a ocorrência de sistemas convectivos de mesoescala na região compreendida entre 15ºS e 27ºS e 35ºW e 55ºW. Os dados de DEA foram cedidos por FURNAS Centrais Elétricas S.A. para o período de 2002-2007. As imagens de satélite geoestacionário, realçadas no canal infravermelho, foram usadas para a identificação dos casos de estudo utilizando o valor limiar de -50ºC para temperatura dos topos das nuvens convectivas. Para estes dias, as DEA detectadas na região de estudo deveriam atingir o valor mínimo de 1000 no intervalo de 1 hora em algum momento de ocorrência dos casos identificados. Dos 565 dias contabilizados desta forma, foram selecionados 25 casos de estudo, ocorridos em 33 dias dos anos 2003, 2005 (de outubro a dezembro, por limitações nas imagens de satélite), 2006 e 2007. Para o período de ocorrência de cada um destes 25 casos, foram contabilizadas as DEA no intervalo de 15 minutos antes e depois do horário das imagens de satélite utilizadas em cada caso, para colocar em evidência as DEA associadas aos aglomerados convectivos observados. Ficou evidenciado que a quantidade de DEA detectadas em um aglomerado convectivo esteve relacionada diretamente com o ciclo evolutivo do mesmo.
Moreira, Gabriela Lameu, and Gabriela Lameu Moreira. "Estudo dos efeitos de parâmetros meteorológicos nas estruturas elétricas de uma linha de instabilidade e de um complexo convectivo de mesoescala na região Sudeste do Brasil." Universidade Federal de Pelotas, 2015. http://repositorio.ufpel.edu.br:8080/handle/prefix/3426.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES
Este trabalho teve como objetivo principal analisar uma Linha de Instabilidade (LI) e um Complexo Convectivo de Mesoescala (CCM) e as condições atmosféricas que conduziram à sua formação, desenvolvimento e geração de descargas elétricas atmosféricas. Estes sistemas ocorreram entre os dias 17 e 19 de outubro de 2007, na região Sudeste do Brasil. A análise dos casos de estudo foi feita em quatro períodos: pré-formação, ocorrência da LI, período de transição e ocorrência do CCM. Para a obtenção dos resultados, a base de dados foi composta por dados de descargas atmosféricas e dados simulados, obtidos com o modelo WRF. As simulações com o modelo WRF foram feitas com três grades aninhadas, de resoluções horizontais de 36, 12 e 4km, que permitiram extrair os campos meteorológicos à grande escala, mesoescala e microescala, respectivamente, bem como o cálculo e análises de alguns parâmetros meteorológicos. Os dados de descargas atmosféricas foram obtidos pela RINDAT (Rede Integrada Nacional de Detecção de Descargas Atmosféricas), que foram sobrepostas às imagens de satélite e aos campos meteorológicos. Dentre os resultados obtidos, observou-se que a região onde os sistemas se formaram e desenvolveram estava propícia para a ocorrência de tempestades, apresentando grande umidade, confluência de ventos, índices de instabilidades com valores que atestavam o potencial de desenvolvimento de tempestades. As condições de grande escala associadas à ocorrência da LI e do CCM apresentaram diferenças e semelhanças, mas em ambos os casos, a atividade elétrica máxima esteve associada ao período mais favorável ao desenvolvimento de correntes ascendentes intensas.
This study had as main objective to analyze a Squall Lines (SL) and a Mesoscale Convective Complex (MCC) and the weather conditions that conducted to its formation, development and generation of lightning. These systems occurred between 17 and 19 October 2007, in Southeastern Brazil. The analysis of the case studies was done in four periods: pre-initiation, occurrence of SL, transition period and occurrence of MCC. To obtain the results, the database consisted of data lightning and simulated data, obtained using the WRF model. The simulations with the WRF model were made with three nested grids with horizontal resolutions of 36, 12 and 4 km, which allowed extracting the meteorological fields to large-scale, mesoscale and microscale, respectively, and an evaluation and analysis of some meteorological parameters. The lightning data were obtained by RINDAT (Rede Integrada Nacional de Detecção de Descargas Atmosféricas), which were superimposed on satellite images and meteorological fields. Among the results, it was observed that the region where the systems were formed and developed was favorable to the occurrence of storms, with high humidity, confluence of winds, instability indices with values that attested to the potential development of storms. The large-scale conditions for the occurrence of SL and MCC showed differences and similarities, but in both cases the maximum electrical activity was associated with more favorable period for the development of intense updrafts.
Lu, Chungu. "A study of positive cloud-to-ground lightning flashes in mesoscale convective systems." Thesis, 1988. http://hdl.handle.net/1957/28616.
Повний текст джерелаGraduation date: 1989
Sindhu, Kapil Dev. "Characteristics of Convective Clouds Over the Indian Monsoon Zone from Weather Radar Data." Thesis, 2018. https://etd.iisc.ac.in/handle/2005/4144.
Повний текст джерелаMahoney, Kelly Marie. "Momentum transport in mesoscale convective systems." 2009. http://www.lib.ncsu.edu/theses/available/etd-08142009-181303/unrestricted/etd.pdf.
Повний текст джерелаLetkewicz, Casey Elizabeth. "Mesoscale convective systems crossing the Appalachian Mountains." 2009. http://www.lib.ncsu.edu/theses/available/etd-07082009-163139/unrestricted/etd.pdf.
Повний текст джерелаGalu, Gideon Kinyodah. "A study of mesoscale convective systems in Kenya." 1998. http://catalog.hathitrust.org/api/volumes/oclc/39551808.html.
Повний текст джерелаTypescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 83-88).
McCormick, Tracy Lynn. "Three-dimensional radar and total lightning characteristics of mesoscale convective systems." 2003. http://www.lib.ncsu.edu/theses/available/etd-08042003-035751/unrestricted/etd.pdf.
Повний текст джерелаChu, Hsin-Yu, and 朱心宇. "The Study on the Impact of Mesoscale Convective Vortices on Tropical Cyclogenesis using Cloud Resolving Model." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/w38t3f.
Повний текст джерела國立臺灣大學
大氣科學研究所
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In this study, Rankine vortices that represent idealized Mesoscale Convective Vortex (MCV) with maximum wind speeds at different levels embedded in a quiescent tropical environment are studied using Vector Vorticity Model (VVM), a three-dimensional, cloud resolving model. We aim to evaluate how different extent of the potential temperature profile modulates the evolution of the initial vortex. Under balanced thermodynamics, positive (negative) potential temperature anomaly will be present above (below) maximum level of potential vorticity. If such profile is optimally placed, the corresponding stabilization is theorized to enhance “bottom heavy” mass flux profile, inducing convergence at lower level, further promoting column saturation and precipitation, contributing to the spin-up of the low-level vortex. The experiment with a Rankine vortex where maximum wind (vmax) located at z = 4.5 km, is the earliest to undergo cyclogenesis, leading other runs by approximately 7 hours or more. The vortex with vmax at sea level or above 7.5km, does not develop after 144 hours. The time required to reach cyclogenesis is proportional to the difference between the level in which vmax is located below or above 4.5 km, where z = 4.5 km seems to be the optimal height to promote genesis. Based on cyclogenesis occurs in 144 hours or not, we can categorize them into developing sets (DS) and non-developing sets (NDS). To analyze the stabilization of thermodynamic environment, we define stability index (SI) based on the difference of saturated moist entropy (s*) between upper and lower troposphere. Smaller (larger) values of SI indicates higher (lower) environmental stability. 48 hours prior to the genesis, the SI of DS systematically decreases, and during the period 0-12 hours prior to the genesis, the median SI of DS is around 5JK^-1kg^-1 lower than that of NDS. The saturation fraction (SF) in DS also shows a systematic increase prior genesis. Joint-PDF of SI and SF confirms the fact that SF is inversely proportional to SI, demonstrating stabilization is accompanied by column saturation. In an environment with higher saturation fraction is more likely to produce large, organized convection. Convective structures that are highly rotational in cyclogenetic environments are phrased as “Vortical Hot Towers (VHTs)” and the increase in number and merger of VHTs plays a notable role as a source of vorticity convergence and heating during genesis. Here we identify the size, height and other characteristics of clouds by connecting cloud grids together as cloud objects using a six-connected segmentation algorithm. After cloud objects are labeled, VHTs are then filtered using cloud thickness exceeding 10 km as the criteria. We then compare the size distribution of these VHTs between the DS and NDS. In the DS, probability density of large VHTs with volumes over 10^4 km3 within a 100×100 km^2 square box around the vortex center steadily overpasses NDS, which is a sign of aggregation and upscale growth 24-36 hours prior to the genesis. Finally, we show that the generation of “bottom-heavy” mass flux profile is more likely in low SI environments by comparing the probability distribution of a bottom-heavy index in low SI and high SI environments. The tendency to generate large VHTs and bottom-heavy mass flux profiles, promotes processes such as organized heating and stretching, which intensifies the incipient vortex.
"Analysis of Mesoscale Convective Systems ocurred in March/2002 on the State of Rio Grande do Sul." Tese, Biblioteca Digital da Universidade Federal de Pelotas, 2004. http://www.ufpel.edu.br/tede/tde_busca/arquivo.php?codArquivo=1.
Повний текст джерела蒲金標. "A case study of the low-level jet and mesoscale convective systems over subtropical China during Mei-yu season." Thesis, 1989. http://ndltd.ncl.edu.tw/handle/76769117802761027302.
Повний текст джерелаTay, LiHui, and 戴俐卉. "The Climate Characteristics of Mesoscale Convective Systems in the Taiwan Mei-Yu Season in the year of 1997 and 1998." Thesis, 2000. http://ndltd.ncl.edu.tw/handle/87225182705880632636.
Повний текст джерелаKumar, Shailendra. "Vertical Structure of Convective Clouds Using the TRMM PR Data." Thesis, 2016. http://etd.iisc.ac.in/handle/2005/4290.
Повний текст джерелаSalzmann, Marc [Verfasser]. "Influences of deep convective cloud systems on tropospheric trace gases and photochemistry over the tropical West Pacific : a modeling case study / Marc Salzmann." 2005. http://d-nb.info/978448774/34.
Повний текст джерелаCeliński-Mysław, Daniel. "Uwarunkowania występowania układów konwekcyjnych z bow echo w Polsce." Praca doktorska, 2020. https://ruj.uj.edu.pl/xmlui/handle/item/277196.
Повний текст джерела