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South Atlantic Ocean cyclogenesis climatology simulated by regional climate model (RegCM3)

REBOITA, Michelle Simoes; ROCHA, Rosmeri Porfirio da; AMBRIZZI, Tercio; SUGAHARA, Shigetoshi
Fonte: SPRINGER Publicador: SPRINGER
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
37.31%
A detailed climatology of the cyclogenesis over the Southern Atlantic Ocean (SAO) from 1990 to 1999 and how it is simulated by the RegCM3 (Regional Climate Model) is presented here. The simulation used as initial and boundary conditions the National Centers for Environmental Prediction-Department of Energy (NCEP/DOE) reanalysis. The cyclones were identified with an automatic scheme that searches for cyclonic relative vorticity (zeta(10)) obtained from a 10-m height wind field. All the systems with zeta(10) a parts per thousand currency sign -1.5 x 10(-5) s(-1) and lifetime equal or larger than 24 h were considered in the climatology. Over SAO, in 10 years were detected 2,760 and 2,787 cyclogeneses in the simulation and NCEP, respectively, with an annual mean of 276.0 +/- A 11.2 and 278.7 +/- A 11.1. This result suggests that the RegCM3 has a good skill to simulate the cyclogenesis climatology. However, the larger model underestimations (-9.8%) are found for the initially stronger systems (zeta(10) a parts per thousand currency sign -2.5 x 10(-5) s(-1)). It was noted that over the SAO the annual cycle of the cyclogenesis depends of its initial intensity. Considering the systems initiate with zeta(10) a parts per thousand currency sign -1.5 x 10(-5) s(-1)...

Hydrographic climatology of South Brazil Bight shelf waters between Sao Sebastiao (24°S) and Cabo Sao Tome (22°S)

Filho, Belmiro Mendes de Castro
Fonte: Biblioteca Digital da Produção Intelectual da USP Publicador: Biblioteca Digital da Produção Intelectual da USP
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
37.2%
A hydrographic climatology was created with the goal of establishing the mean hydrographic conditions and oceanic waters intrusion mechanisms in the central and northern parts of the South Brazil Bight on a seasonal timescale. The climatology was constructed by applying objective analysis to a historical temperature and salinity database, by season and depth, considering the anisotropy and coastal and oceanic boundary conditions. The dominance of South Atlantic Central Water (SACW) in the bottom layer, the presence of Tropical Water in the surface layer, the seasonal onshore–offshore displacement of those water masses, and the along-shore remote southward advection of SACW from Cabo Frio (23°S) are well-defined features in the analyzed and derived fields. The inshore displacement increases the volume of SACW in the shelf by approximately 780 km3 from winter to spring; the offshore displacement decreases the volume of SACW by approximately 840 km3 from summer to autumn. The remote advection is linked to southwestward, along-shelf transport of SACW with temperatures lower than 15 °C from Cabo Frio during summer, winter, and spring. In association with the remote advection, a primary intrusion pathway of SACW is identified off Cabo Frio during those same three seasons. In spring...

Observed and simulated (RegCM4) climatology of the cold fronts over the cities of São Paulo (1981-2002) and Rio Grande (1991-2008)

Jesus, Eduardo Marcos de; Rocha, Rosmeri Porfirio da
Fonte: Sociedade Brasileira de Meteorologia; Florianópolis Publicador: Sociedade Brasileira de Meteorologia; Florianópolis
Tipo: Conferência ou Objeto de Conferência
ENG
Relevância na Pesquisa
37.31%
The objective of this work was to investigate as RegCM4 model forced in the boundary with as Era-Interim dataset simulates the climatology of frontal systems over the states of Rio Grande do Sul and São Paulo. The cold fronts obtained from RegCM4 were compared with Água Funda (IAG-USP, period of 1981-2002) and FURG-RS weather stations for the period 1991-2008. The cold fronts were identified using an algorithm that checks the tuming of the wind at same time the there is temperature decreases. This algorithm was applied to the four seasons: summer, auturnn, winter and spring. The results show that RegCM4 identifies smaller number of fronts over the city of Rio Grande, underestimating about 15% of total fronts and this underestimation persists in other seasons. In the São Paulo city, RegCM4 overestimates (positive bias) the number of fronts in only 1%, but this overestimates does not persist in all seasons summer and autumn presenting underestimation of about -20% and -2%, respectively. As in São Paulo, in Rio Grande the largest underestimation of fronts by RegCM4 occurs in the summer (~-19%). The climatology of the some meteorological variables was obtained from two day before until two days after the passage of the fronts. In this climatology it was noted large agreement between RegCM4 and observations. Over the city of São Paulo (Rio Grande)...

Climatology of Easterly Wave Disturbances of Northeast Brazil

Gomes, Helber Barros; Ambrizzi, Tercio; Herdies, Dirceu Luís; Hodges, K. I.
Fonte: Sociedade Brasileira de Meteorologia; Florianópolis Publicador: Sociedade Brasileira de Meteorologia; Florianópolis
Tipo: Conferência ou Objeto de Conferência
ENG
Relevância na Pesquisa
37.04%
A 21-year climatology of Easterly Wave Disturbances (EWDs) over Northeastem Brazil (NEB) region was constructed in order to obtain a better understanding of dynamic and synoptic processes life cycle of these systems, including genesis, growth I decay, trajectory and dissipation. The identification of EWDs was obtained subjectively through satellite images in infrared channel and fields of streamlines and relative vorticity at the levels 1000, 850, 700, 500 and 200 hPa from ERA-Interim reanalysis. During this period, 518 EWDs were identified, where 97% (3%) ofthese waves reach (do not reach) the NEB region, 64% (36%) were convective (non-convective) and 14% (86%) reached the Amazon region. The main systems that gave rise to DOLs were: Intertropical Convergence Zone (ITCZ), Upper- Tropospheric Cyclonic Vortices (UTCV), Cold Fronts (FF) and convective clusters from the west coast of Africa (AF). In addition, the interactions between systems AFIFF, AFIITCZ, AFIUTCV and ITCZIFF were associated with their formation. On average, we observed approximately 25 waves per year, with maximum (minimum) frequency between the months ofMarch to August (September to February) and, with pronounced interannual variability.; Título: V SIC: Interação oceano-atmosfera: impactos climáticos no presente e cenários futuros. Eventos simultâneos ao V SIC: Encontro Sul Brasileiro de Meteorologia...

Veranicos ocorridos na porção noroeste do estado do Rio Grande do Sul entre 1978 e 2005 e sua associação às condições climáticas na atmosfera; Dry spells occurrence in the northwest portion of Rio Grande do Sul state between the years 1978 and 2005 and its association to the climatic conditions in the atmosphere

Sleiman, Jorge
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 07/11/2008 PT
Relevância na Pesquisa
27.2%
A atividade agrícola é muito importante para a economia do Rio Grande do Sul, cuja região alvo deste estudo é sua porção noroeste, representada por seis municípios: São Luiz Gonzaga, Santa Rosa, Cruz Alta, Iraí, Passo Fundo e Marcelino Ramos. Esta região é foco nacional de produção de soja, dependendo fortemente das condições atmosféricas, tanto em escala sinótica quanto climática. Os períodos secos, conhecidos como veranicos, durante a fase de desenvolvimento até a colheita, que acorrem entre outubro e março, acarretam vários prejuízos à região. O objetivo do trabalho é estimar a climatologia de ocorrência de veranicos no NW do RS, no primeiro e quarto trimestres do ano, entre 1978 e 2005 e associá-los a padrões atmosféricos característicos. Verificou-se que o maior número de veranicos ocorre no primeiro trimestre em relação ao quarto, resultado que apresenta correlação direta com o volume médio climatológico de precipitação para esses 2 trimestres. Março e dezembro apresentam mais eventos secos do que os outros meses, o que parece ser resposta direta de menor volume de chuva. Por outro lado, numa análise espacial, Santa Rosa e São Luiz Gonzaga apresentam os maiores números de veranicos...

Distúrbios ondulatórios de leste no nordeste brasileiro: climatologia e modelagem numérica; Easterly waves Disturbances over Northeast Brazil: Climatology and Numerical Modeling.

Gomes, Helber Barros
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 22/10/2012 PT
Relevância na Pesquisa
37.04%
Uma climatologia de 21 anos dos Distúrbios Ondulatórios de Leste (DOLs) sobre a região NEB foi realizada com o intuito de obter um melhor entendimento dos processos dinâmicos e sinóticos do ciclo de vida destes sistemas, incluindo gênese, crescimento/decaimento, trajetória e dissipação. Adicionalmente, foi avaliada a eficiência do modelo de mesoescala WRF em simular este tipo de sistema. A identificação dos DOLs foi obtida de forma subjetiva através de imagens de satélite no canal infravermelho e campos de linhas de corrente e vorticidade relativa nos níveis de 1000, 850, 700, 500 e 200 hPa da reanálise do ERA-Interim. Neste período foram identificados 518 eventos de DOLs, onde 97% (3%) dessas ondas atingiram (não atingiram) a região do NEB, 64% (36%) foram convectivas (não convectivas) e 14% (86%) atingiram a região da Amazônia. Os principais sistemas que deram origem aos DOLs foram: Zona de Convergência Intertropical (ZCIT), Vórtice Ciclônico de Altos Níveis (VCAN), Frentes Frias (FF) e conglomerados convectivos provenientes da costa oeste da África (AF). Além destes, a interação entre os sistemas AF/FF, AF/ZCIT, AF/VCAN e ZCIT/FF estiveram associadas a sua formação. Em média, foram observadas aproximadamente 25 ondas por ano...

Climatologia aplicada à arquitetura: investigação experimental sobre a distribuição de temperaturas internas em duas células de teste; Climatology applied to architecture: an experimental investigation about internal temperatures distribution at two test cells

Seixas, Grace Tibério Cardoso de
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 20/03/2015 PT
Relevância na Pesquisa
37.04%
Este trabalho de caráter investigativo analisou a distribuição espacial de temperaturas superficiais internas (TSI) e temperatura interna do ar ou de bulbo seco (TBS), em duas células de teste distintas, para dois dias típicos experimentais, um sob a influência da massa tropical, e outro sob o domínio da massa polar atlântica. O objetivo desta pesquisa é fornecer diretrizes para coleta de dados experimentais de temperatura, visto que não existe uma norma adequada que oriente este procedimento metodológico em edificações. Esta investigação foi realizada a partir das abordagens espacial e temporal da Climatologia Dinâmica, como forma de conhecer a influência das flutuações do tempo meteorológico (episódios climáticos), sobre os valores das temperaturas internas das duas edificações experimentais. As séries de dados de temperaturas de bulbo seco e superficiais internas foram coletadas em uma células de teste com cobertura verde e outra com telhado cerâmico convencional, por meio de termopares instalados em locais prédeterminados. Os dados de radiação solar global e das principais variáveis climáticas foram registrados pela estação meteorológica automática do Centro de Ciências da Engenharia Aplicadas ao Meio Ambiente (CCEAMA)...

Teoria e método da climatologia geográfica brasileira: uma abordagem sobre seus discursos e práticas

Ely, Deise Fabiana
Fonte: Universidade Estadual Paulista (UNESP) Publicador: Universidade Estadual Paulista (UNESP)
Tipo: Tese de Doutorado Formato: 208 f. : il., gráf.
POR
Relevância na Pesquisa
27.31%
Pós-graduação em Geografia - FCT; O presente trabalho constitui um mapeamento e análise sobre os discursos e práticas empreendidos pela climatologia geográfica brasileira. O principal propósito para o seu desenvolvimento foi a verificação de como o conhecimento geográfico do clima encontra-se vinculado aos debates efetivados pelas diversas correntes filosóficas de pensamento e às diferentes concepções de natureza e de geografia. A verificação do processo de inserção e constituição dessa especialidade científica no Brasil demonstrou a existência de duas vertentes metodológicas principais: uma baseada em decomposições analítico-descritivas do fenômeno climático e outra subsidiada nas explicações da meteorologia dinâmica. O estudo geográfico do clima, a partir desse universo de análise, é desenvolvido a partir de cinco recortes temáticos principais: clima urbano, variabilidade pluvial, o clima na análise ambiental e da paisagem, modelagem estatística em climatologia e teoria e método da climatologia; pautados na concepção de natureza dinâmica-sistêmica. Foi verificado que as questões epistemológicas da Geografia não são refletidas enfaticamente pela climatologia geográfica brasileira, tornando a apreensão da espacialidade do clima na composição das novas territorialidades uma tarefa difícil de ser realizada.; The main purpose of this following thesis is to verify how the geographic knowledge of the climate relates to debates about diverse philosophical trends and the different conceptions of nature and geography...

Climatology of cyclones, anticyclones and storm tracks: revision of concepts

Mendes,David; Mendes,Monica Damião
Fonte: Sociedade Brasileira de Geofísica Publicador: Sociedade Brasileira de Geofísica
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/08/2004 EN
Relevância na Pesquisa
37.2%
This paper has the finality of describe climatology of extratropical cyclones, anticyclones and storm tracks for the NH and SH. There is a long history of studies on the characteristics of synoptic systems, beginning with classical work on mid-latitude cyclones. For the SH, analyses of pressure data provide extensive statistics of the climatology of synoptic systems. Interestingly, the anticyclones mean central pressure at 38ºS in JJA and 44ºS in DJF. SH cyclones are characterized in frequency maximum in the circumpolar trough between about 50ºS and 70ºS. For the NH cyclones, the principal findings of the analysis are as follows: In January the primary maxima are in the western North Atlantic, with a peak about 45º - 50ºN, where there is a secondary peak, over the north-central Mediterranean; These characteristics are similar in April but with decrease in the frequency of centers; In July the frequencies are further reduced and the hemisphere maximum is over eastern Canada at 55ºN; The October pattern resembles that of winter, except that the Atlantic maximum is off southeast Greenland.

A smart climatology of evaporation duct height and surface radar propagation in the Indian Ocean

Twigg, Katherine L.
Fonte: Monterey, California. Naval Postgraduate School Publicador: Monterey, California. Naval Postgraduate School
Tipo: Tese de Doutorado
Relevância na Pesquisa
27.62%
Surface electromagnetic propagation over the ocean is highly sensitive to near-surface atmospheric variability, particularly the height of the evaporation duct. Seasonal variation in near-surface meterological factors and sea surface temperatures impact the evaporation duct height (EDH). Present U.S. Navy EDH climatology is based on sparse ship observations over a relatively short time period and an outdated evaporation duct (ED) model. This EDH climatology does not utilize smart, or modern, climatology datasets or methods and provides only long term mean (LTM) values of EDH. We have used existing, civilian, dynamically balanced reanalysis data, for 1970 to 2006, and a state-of-the-art ED model, to produce a spatially and temporally refined EDH climatology for the Indian Ocean (IO) and nearby seas. Comparisons of the present U.S. Navy EDH climatology with our climatology show a number of differences. These differences, and the differences in the methods used to generate the two climatologies, indicate that the EDH climatology we have generated provides a more accurate depiction of EDH. The EDH climatology we have produced provides LTM EDH values. But the data and methods we used to create this climatology also allowed us to examine the impacts of climate variations on EDH. Climate variations can have major impacts on the upper ocean and overlying lower troposphere. These impacts can lead to major fluctuations in the factors that determine EDH...

Decision modeling for smart climatology

Regnier, Eva
Fonte: Monterey, California. Naval Postgraduate School Publicador: Monterey, California. Naval Postgraduate School
Tipo: Relatório
Relevância na Pesquisa
27.31%
The views expressed in this report are those of the author and do not reflect the official policy or position of the Department of Defense or the U.S. Government.; The purpose of smart climatology is to provide information that would be useful in operational planning at lead times of two to four weeks or greater. Decisions made at shorter lead-times are generally informed by forecasts. One of the challenges in designing a new climatology data system--to include generation, storage, and access--is anticipating how the data might be used, and therefore how to design the system to provide the most useful data in their most useful format. This report uses an operations research / decision analysis (OR/DA) approach to prototype the process of using smart climatology data in planning, and identify challenges and key features of decision-relevant climatology data system.

Climatic variations of the California current system application of smart climatology to the coastal ocean

Feldmeier, Joel W.
Fonte: Monterey, California. Naval Postgraduate School Publicador: Monterey, California. Naval Postgraduate School
Tipo: Tese de Doutorado Formato: xx, 146 p. : col. ill.
Relevância na Pesquisa
37.39%
TRACT (maximum 200 words) The Northern Oscillation Index (NOI), an atmospheric climate index relating climate variations in the tropical Pacific and Northeast Pacific was used to selectively average output from the Parallel Ocean Climate Model (POCM 4C) for 1979-1998. Composites, or smart climatologies, were made representing El Nino (EN) and La Nina (LN) conditions, as well as a long term mean (LTM) average or traditional climatology, for November to March. Conditions in the California Current System (CCS) in the smart climatologies were consistent with large scale features noted in previously published studies of EN and LN. Overall, the patterns of anomalies (POCM 4C Smart Climatology minus POCM 4C Traditional Climatology) in salinity, temperature, and currents were opposite in sign and magnitude between the EN and LN composites. This was expected for opposite phases of the same climate variation, and many of the model's EN/LN differences were found to be statistically significant. Therefore, POCM 4C smart climatologies provide better estimates of ocean state and circulation patterns than traditional climatology. Such smart climatologies offer improved environmental information to Naval operational and strategic planners. They are also useful for studying climate variations...

GEOCLIM : a global climatology of LAI, FAPAR, and FCOVER from VEGETATION observations for 1999-2010

Verger Ten, Aleixandre; Baret, Frédéric; Weiss, Marie; Filella Cubells, Iolanda; Peñuelas, Josep
Fonte: Universidade Autônoma de Barcelona Publicador: Universidade Autônoma de Barcelona
Tipo: info:eu-repo/semantics/article; info:eu-repo/semantics/acceptedVersion
Publicado em //2015 ENG
Relevância na Pesquisa
37.2%
Altres ajuts: Programes Copernicus, le Pôle Thématique Surfaces Continentales THEIA, GIOBIO (32-566) i LONGLOVE (32-594).; Land-surface modelling would benefit significantly from improved characterisation of the seasonal variability of vegetation at a global scale. GEOCLIM, a global climatology of leaf area index (LAI), fraction of absorbed photosynthetically active radiation (FAPAR)—both essential climate variables—and fraction of vegetation cover (FCOVER), is here derived from observations from the SPOT VEGETATION programme. Interannual average values from the GEOV1 Copernicus Global Land time series of biophysical products at 1-km resolution and 10-day frequency are computed for 1999 to 2010. GEOCLIM provides the baseline characteristics of the seasonal cycle of the annual vegetation phenology for each 1-km pixel on the globe. The associated standard deviation characterises the interannual variability. Temporal consistency and continuity is achieved by the accumulation of multi-year observations and the application of techniques for temporal smoothing and gap filling. Specific corrections are applied over cloudy tropical regions and high latitudes in the Northern Hemisphere where the low number of available observations compromises the reliability of estimates. Artefacts over evergreen broadleaf forests and areas of bare soil are corrected based on the expected limited seasonality. The GEOCLIM data set is demonstrated to be consistent...

OS CLÁSSICOS DA CLIMATOLOGIA GEOGRÁFICA: A CONTRIBUIÇÃO PIONEIRA DE ELLSWORTH HUNTINGTON; THE CLASSIC AUTHORS OF GEOGRAPHICAL CLIMATOLOGY: THE PRECURSORY CONTRIBUITION OF ELLSWORTH HUNTINGTON

Junior, Ilton Jardim de Carvalho
Fonte: Programa de Pós-Graduação em Geografia Humana. Universidade de São Paulo. Publicador: Programa de Pós-Graduação em Geografia Humana. Universidade de São Paulo.
Tipo: info:eu-repo/semantics/article; info:eu-repo/semantics/publishedVersion; Formato: application/pdf
Publicado em 30/12/2012 POR
Relevância na Pesquisa
37.04%
Este artigo pretende fazer uma releitura crítica de uma das obras mais polêmicas da Geografia, “Civilization and Climate”, de Ellsworth Huntington. Autor prolífico e de teorias ousadas e complexas, foi pioneiro na nascente ciência climatológica, ao contribuir para seu avanço teórico, metodológico e epistemológico. Sua obra, injustamente desmerecida por grande parte da crítica, lidou com grandes hipóteses centrais da ciência geográfica, como a relação sociedade-natureza e a controversa teoria das influências ambientais. A análise pormenorizada de “Civilization and Climate”, baseada na análise imparcial e justa de alguns comentadores, mostrou que Huntington merece ser lembrado pela seriedade e ousadia de suas pesquisas e idéias, pela complexidade de suas teorias, e pelo pioneirismo de suas metodologias.  ; This essay aims at analyzing the masterwork of Huntington, “Civilization and Climate”, one of the most polemic geographical works, in order to show how unfair were the critics launched to Huntington´s complex and precursor theories, particularly the environmentalist theory, established from the relation between climate and society. The careful analysis was supported by some renowned scholars who have done an impartial and unbiased job...

A synoptic climatology of severe hail in the northeastern United States

Kerschner, Brian
Fonte: University of Delaware Publicador: University of Delaware
Tipo: Tese de Doutorado
Relevância na Pesquisa
37.2%
Leathers, Daniel J.; A climatology of severe hail (3/4 inches or greater) was constructed for the Northeastern Unites States (Figure 3.1). This region was chosen because it contains highly populated urban environments adjacent to vast agricultural regions, both of which are susceptible to hail damage. This study provides a baseline climatology of severe hail throughout the Northeast United States (from 1955-2009) by investigating the spatial and temporal characteristics of severe hail storms, and the extent to which population density influences severe hail reports. Synoptic patterns and thermodynamic environments are also discussed by analyzing data from the top 85 most reported severe hail outbreaks, defined as significant severe hail event days. This data consists of daily mean composite synoptic weather maps, as well as information from nine upper air stations throughout the study region. The results show that the distribution of severe hail in the Northeastern United States is influenced by a combination of meteorological, technological, and societal factors. The daily mean composite synoptic maps show that significant severe hail outbreaks in the Northeastern United States commonly occur when the region is influenced by the ascending branch of a low amplitude...

The climatology of the Delaware Bay/Sea Breeze

Hughes, Christopher
Fonte: University of Delaware Publicador: University of Delaware
Tipo: Tese de Doutorado
Relevância na Pesquisa
37.31%
Veron, Dana E.; The sea-breeze circulation is a coastal phenomenon that is of great importance to the Delaware community. The sea breeze is a mesoscale occurrence that is driven by the temperature difference of air over the land and the sea. A sea breeze front can cause drastic changes in wind direction, wind speed, and temperature which can have a significant effect on tourism, pollution, coastal ocean currents, and wind power potential. The wind climatology over Delaware and its corresponding coastal regions is investigated using meteorological stations and output from the Weather Research and Forecasting Model (WRF). Significant summertime diurnal variations are found between coastal and inland areas in both observed and modeled data. Additional climatological wind variations are observed between stations over the Delaware Bay (BRND1) and nearby open ocean (Buoy #44009). The climatology of the Delaware Bay/Sea Breeze is investigated using radar data, synoptic maps, meteorological stations, and WRF. Three sea breeze classifications are designated based on changes in dew point, temperature, and wind magnitude. A sea breeze detection algorithm was created which searches for classic sea breeze days with large temperature drops and estimates their time of occurrence. The large concentration of stations per area...

A synoptic climatology of tornadoes in the northeast United States

Benjamin, Andrew
Fonte: University of Delaware Publicador: University of Delaware
Tipo: Tese de Doutorado
Relevância na Pesquisa
37.2%
Leathers, Daniel; A tornado climatology is constructed for the northeast United States. Few studies have focused on this portion of the country due to the fact that this region reports fewer tornados than the other areas of the United States. However, this region is highly susceptible to tornado damage as it boasts dense populations and includes several major cities where the risk of tornadoes is often ignored. This study provides a general climatology of tornadoes in the northeast United States from 1950-2010 by exploring the spatial and temporal characteristics of Northeast tornadoes in addition to potential population influences on tornado reporting. Additionally, 161 days defined as significant tornado days are used to examine the synoptic patterns and thermodynamic characteristics of Northeast tornado environments. The results indicate that tornado reports have increased since 1950, however most of this increase is due to better reporting practices and enhanced monitoring technology, especially Doppler radar. Tornadoes in the Northeast were most frequently reported in the late afternoon/early evening hours, between 1300-1900 LST. July was the peak month for tornado reports, while December reported the fewest. Around 75% of all Northeast tornadoes were given an Enhanced Fujita scale intensity rating of 1 or lower. A linear regression analysis found that approximately 38% of the variance in the spatial distribution of tornadoes can be explained by population. The composite synoptic maps indicate that Northeast tornado outbreaks are commonly associated with a 500 hPa trough and surface low pressure system over the Great Lakes. A distinct cold front is found ahead of the trough...

A synoptic climatology of severe convective winds in the northeastern United States

Hayes, Alison
Fonte: University of Delaware Publicador: University of Delaware
Tipo: Tese de Doutorado
Relevância na Pesquisa
37.04%
Leathers, Daniel J.; Although much research has been conducted investigating the spatial distribution of severe convective winds in many areas of the United States, few studies have focused specifically on the Northeast. Because of the large population and general lack of hazard awareness, high wind disasters are most common in this section of the country. This study provides a baseline climatology of severe convective wind reports from 1955-2010 using data from the Storm Prediction Center. Population biases inherent in the dataset as well as synoptic and thermodynamic environments associated with ???significant??? event days are examined in order to better understand the meteorological characteristics specific to the region that are responsible for severe convective surface winds. After a population-bias model is applied to the data, ???hot spots??? for wind reports are identified along the windward and leeward sides of the Appalachian Range, with significant clusters positioned in upstate New York and west of Washington D.C. The highest number of wind reports occurs diurnally around 2100 GMT and in the months of June and July on an annual basis. Synoptically, high numbers of events occur when there is anomalous low pressure north of New York state in association with a low-amplitude trough at the 500 hPa pressure level. Thermodynamic information obtained from 00z soundings at 11 upper air stations in the Northeast show that although severe weather indices are not necessarily good indicators of hazardous weather in every region...

DECÁLOGO DA CLIMATOLOGIA DO SUDESTE BRASILEIRO; THE TEN COMMANDMENTS OF THE SOUTHEAST BRASILIAN CLIMATOLOGY

Sant'Anna Neto, João Lima
Fonte: UFPR Publicador: UFPR
Tipo: info:eu-repo/semantics/article; info:eu-repo/semantics/publishedVersion; Formato: application/pdf
Publicado em 18/05/2011 POR
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These paper discuss the southeast Brazilian climatology using as a strategy, the Ten Commandments (or then characteristics) of factors and dynamics that explains its genesis. To support it, the major bibliography of climate studies, including Edmon Nimer (1979) classical text book was utilized to analyses general principles and particularities of regional climates. Aims to demonstrate how localization, relief altimetry, the vaster coastal zone, plains, highlands an interior valleys, introducing in a very complex schedule of atmospheric dynamics, produces unique peculiarities making the southeast Brazilian region presents one of the most varieties of climatic types.; Este artigo rediscute a climatologia regional do Sudeste brasileiro utilizando como estratégia, os dez mandamentos (ou dez características) fundamentais dos fatores e dinâmicas que explicam a sua gênese. Apóia-se no clássico trabalho de Edmon Nimer (1979) e em vasta bibliografia para colocar em discussão os princípios gerais e as particularidades dos climas regionais. Objetiva demonstrar como a localização, a rugosidae do relevo, a vasta zona costeira e os planaltos e vales interiores, inseridos num quadro de dinâmica atmosférica complexa...

The lightning climatology of South Africa

Gijben,Morné
Fonte: South African Journal of Science Publicador: South African Journal of Science
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2012 EN
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In 2005, the South African Weather Service installed a state-of-the-art cloud-to-ground lightning detection network across the country. The data recorded by this network in 2006 was utilised in the development of an initial lightning climatology of South Africa. Until 2010, this climatology was based on data from a single year. This paper updates this climatology with the lightning data for the 2006-2010 period, which is the first actual lightning climatology by the South African Weather Service based on data covering 5 years. A number of different maps were created from these lightning data. These were lightning ground flash density, median peak kiloampere, percentage positive and average flash multiplicity maps. These four maps were in turn used to develop lightning intensity risk, positive lightning risk and total lightning risk maps. Analysis of the maps showed that the highest concentrations of lightning are found over the central to northern interior of the country, with areas along the northern parts of the eastern escarpment experiencing the highest flash densities and falling within the extreme risk category. Both the positive and total lightning risks are severe for almost the entire country. Only towards the west of the country does the lightning risk decrease. This lightning climatology can now be used throughout South Africa for various disciplines. It will be especially useful for setting lightning safety standards and identifying priority areas for installing lightning conductors and conducting public awareness campaigns.