Modelos de dispersão para extremos de precipitação. Estudo de caso: o nordeste do Brasil

In this thesis used four different methods in order to diagnose the precipitation extremes on Northeastern Brazil (NEB): Generalized Linear Model s via logistic regression and Poisson, extreme value theory analysis via generalized extre me value (GEV) and generalized Pareto (GPD) distributions and Vectorial Generalized Linea r Models via GEV (MVLG GEV). The logistic regression and Poisson models were used to identify the interactions between the precipitation extremes and other variables based on the odds ratios and relative risks. It was found that the outgoing longwave radiation was the indicator variable for the occurrence of extreme precipitation on eastern, northern and semi arid NEB, and the relative humidity was verified on southern NEB. The GEV and GPD distribut ions (based on the 95th percentile) showed that the location and scale parameters were presented the maximum on the eastern and northern coast NEB, the GEV verified a maximum core on western of Pernambuco influenced by weather systems and topography. The GEV and GPD shape parameter, for most regions the data fitted by Weibull negative an d Beta distributions (ξ < 0) , respectively. The levels and return periods of GEV (GPD) on north ern Maranhão (centerrn of Bahia) may occur at least an extreme precipitation event excee ding over of 160.9 mm /day (192.3 mm / day) on next 30 years. The MVLG GEV model found tha t the zonal and meridional wind components, evaporation and Atlantic and Pacific se a surface temperature boost the precipitation extremes. The GEV parameters show the following results: a) location ( ), the highest value was 88.26 ± 6.42 mm on northern Maran hão; b) scale ( σ ), most regions showed positive values, except on southern of Maranhão; an d c) shape ( ξ ), most of the selected regions were adjusted by the Weibull negative distr ibution ( ξ < 0 ). The southern Maranhão and southern Bahia have greater accuracy. The level period, it was estimated that the centern of Bahia may occur at least an extreme precipitatio n event equal to or exceeding over 571.2 mm/day on next 30 years.

Impacto de los eventos extremos en la construcción de portafolios de inversión eficientes

El presente trabajo de investigación busca medir el impacto que tienen los eventos extremos, también llamados eventos de boom o eventos de crash, según la naturaleza y consecuencias de los mismos en la construcción de portafolios de inversión eficientes -- Se trabajará con los precios de acciones listadas en la bolsa de Nueva York, y con estas se construirán portafolios de inversión, siguiendo la metodología diseñada por Harry Markowitz en 1952 -- Se verificará la rentabilidad de los portafolios antes del evento extremo, y después de este, y se estudiarán las consecuencias de este sobre el portafolio -- El evento extremo que se introducirá en el estudio es la crisis económica y financiera del año 2008, que tiene sus orígenes en la crisis hipotecaria en Estados Unidos -- Con las variaciones en los precios de los activos en dicho periodo de tiempo, se espera estresar el modelo y revisar si lo propuesto por Markowitz sigue teniendo validez ante la aparición de dichos sucesos -- A partir de esto, se realizarán simulaciones con modelos en Excel y técnicas de Montecarlo, se plantearán posibles recomendaciones técnicas que debamos tener en cuenta al momento de construir nuestros portafolios, y se redactará un documento con recomendaciones para los inversionistas en general -- Como aporte adicional, se entregará el código en Visual Basic para automatizar la optimización de los portafolios

Análise das tragédias de Janeiro de 2011, no bairro jardim Zaíra, município de Mauá/SP: uma análise episódica

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Estudo do balanço de umidade por meio de modelos regionais para o clima do passado e do futuro sobre a América do Sul

In the context of climate change over South America (SA) has been observed that the combination of high temperatures and rain more temperatures less rainfall, cause different impacts such as extreme precipitation events, favorable conditions for fires and droughts. As a result, these regions face growing threat of water shortage, local or generalized. Thus, the water availability in Brazil depends largely on the weather and its variations in different time scales. In this sense, the main objective of this research is to study the moisture budget through regional climate models (RCM) from Project Regional Climate Change Assessments for La Plata Basin (CLARIS-LPB) and combine these RCM through two statistical techniques in an attempt to improve prediction on three areas of AS: Amazon (AMZ), Northeast Brazil (NEB) and the Plata Basin (LPB) in past climates (1961-1990) and future (2071-2100). The moisture transport on AS was investigated through the moisture fluxes vertically integrated. The main results showed that the average fluxes of water vapor in the tropics (AMZ and NEB) are higher across the eastern and northern edges, thus indicating that the contributions of the trade winds of the North Atlantic and South are equally important for the entry moisture during the months of JJA and DJF. This configuration was observed in all the models and climates. In comparison climates, it was found that the convergence of the flow of moisture in the past weather was smaller in the future in various regions and seasons. Similarly, the majority of the SPC simulates the future climate, reduced precipitation in tropical regions (AMZ and NEB), and an increase in the LPB region. The second phase of this research was to carry out combination of RCM in more accurately predict precipitation, through the multiple regression techniques for components Main (C.RPC) and convex combination (C.EQM), and then analyze and compare combinations of RCM (ensemble). The results indicated that the combination was better in RPC represent precipitation observed in both climates. Since, in addition to showing values be close to those observed, the technique obtained coefficient of correlation of moderate to strong magnitude in almost every month in different climates and regions, also lower dispersion of data (RMSE). A significant advantage of the combination of methods was the ability to capture extreme events (outliers) for the study regions. In general, it was observed that the wet C.EQM captures more extreme, while C.RPC can capture more extreme dry climates and in the three regions studied.

Estudo estatístico sobre eventos de precipitação intensa no nordeste do Brasil

The Northeast of Brazil (NEB) shows high climate variability, ranging from semiarid regions to a rainy regions. According to the latest report of the Intergovernmental Panel on Climate Change, the NEB is highly susceptible to climate change, and also heavy rainfall events (HRE). However, few climatology studies about these episodes were performed, thus the objective main research is to compute the climatology and trend of the episodes number and the daily rainfall rate associated with HRE in the NEB and its climatologically homogeneous sub regions; relate them to the weak rainfall events and normal rainfall events. The daily rainfall data of the hydrometeorological network managed by the Agência Nacional de Águas, from 1972 to 2002. For selection of rainfall events used the technique of quantiles and the trend was identified using the Mann-Kendall test. The sub regions were obtained by cluster analysis, using as similarity measure the Euclidean distance and Ward agglomerative hierarchical method. The results show that the seasonality of the NEB is being intensified, i.e., the dry season is becoming drier and wet season getting wet. The El Niño and La Niña influence more on the amount of events regarding the intensity, but the sub-regions this influence is less noticeable. Using daily data reanalysis ERAInterim fields of anomalies of the composites of meteorological variables were calculated for the coast of the NEB, to characterize the synoptic environment. The Upper-level cyclonic vortex and the South atlantic convergene zone were identified as the main weather systems responsible for training of EPI on the coastland

Modelagem estatística e atribuições dos eventos de precipitação extrema na Amazônia brasileira

Intense precipitation events (IPE) have been causing great social and economic losses in the affected regions. In the Amazon, these events can have serious impacts, primarily for populations living on the margins of its countless rivers, because when water levels are elevated, floods and/or inundations are generally observed. Thus, the main objective of this research is to study IPE, through Extreme Value Theory (EVT), to estimate return periods of these events and identify regions of the Brazilian Amazon where IPE have the largest values. The study was performed using daily rainfall data of the hydrometeorological network managed by the National Water Agency (Agência Nacional de Água) and the Meteorological Data Bank for Education and Research (Banco de Dados Meteorológicos para Ensino e Pesquisa) of the National Institute of Meteorology (Instituto Nacional de Meteorologia), covering the period 1983-2012. First, homogeneous rainfall regions were determined through cluster analysis, using the hierarchical agglomerative Ward method. Then synthetic series to represent the homogeneous regions were created. Next EVT, was applied in these series, through Generalized Extreme Value (GEV) and the Generalized Pareto Distribution (GPD). The goodness of fit of these distributions were evaluated by the application of the Kolmogorov-Smirnov test, which compares the cumulated empirical distributions with the theoretical ones. Finally, the composition technique was used to characterize the prevailing atmospheric patterns for the occurrence of IPE. The results suggest that the Brazilian Amazon has six pluvial homogeneous regions. It is expected more severe IPE to occur in the south and in the Amazon coast. More intense rainfall events are expected during the rainy or transitions seasons of each sub-region, with total daily precipitation of 146.1, 143.1 and 109.4 mm (GEV) and 201.6, 209.5 and 152.4 mm (GPD), at least once year, in the south, in the coast and in the northwest of the Brazilian Amazon, respectively. For the south Amazonia, the composition analysis revealed that IPE are associated with the configuration and formation of the South Atlantic Convergence Zone. Along the coast, intense precipitation events are associated with mesoscale systems, such Squall Lines. In Northwest Amazonia IPE are apparently associated with the Intertropical Convergence Zone and/or local convection.

Análise da precipitação no semi-árido potiguar

The semiarid rainfall regime is northeastern Brazil is highly variable. Climate processes associated with rainfall are complex and their effects may represent extreme situations of drought or floods, which can have adverse effects on society and the environment. The regional economy has a significant agricultural component, which is strongly influenced by weather conditions. Maximum precipitation analysis is traditionally performed using the intensity-duration-frequency (IDF) probabilistic approach. Results from such analysis are typically used in engineering projects involving hydraulic structures such as drainage network systems and road structures. On the other hand, precipitation data analysis may require the adoption of some kind of event identification criteria. The minimum inter-event duration (IMEE) is one of the most used criteria. This study aims to analyze the effect of the IMEE on the obtained rain event properties. For this purpose, a nine-year precipitation time series (2002- 2011) was used. This data was obtained from an automatic raingauge station, installed in an environmentally protected area, Ecological Seridó Station. The results showed that adopted IMEE values has an important effect on the number of events, duration, event height, mean rainfall rate and mean inter-event duration. Furthermore, a higher occurrence of extreme events was observed for small IMEE values. Most events showed average rainfall intensity higher than 2 mm.h-1 regardless of IMEE. The storm coefficient of advance was, in most cases, within the first quartile of the event, regardless of the IMEE value. Time series analysis using partial time series made it possible to adjust the IDF equations to local characteristics

Dowscaling estocástico para extremos climáticos via interpolação espacial

Present day weather forecast models usually cannot provide realistic descriptions of local and particulary extreme weather conditions. However, for lead times of about a small number of days, they provide reliable forecast of the atmospheric circulation that encompasses the subscale processes leading to extremes. Hence, forecasts of extreme events can only be achieved through a combination of dynamical and statistical analysis methods, where a stable and significant statistical model based on prior physical reasoning establishes posterior statistical-dynamical model between the local extremes and the large scale circulation. Here we present the development and application of such a statistical model calibration on the besis of extreme value theory, in order to derive probabilistic forecast for extreme local temperature. The dowscaling applies to NCEP/NCAR re-analysis, in order to derive estimates of daily temperature at Brazilian northeastern region weather stations

Ocorrência de eventos climáticos extremos e sua repercurssão sócio-ambiental no litoral norte paulista

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Risco climático, vulnerabilidade socioespacial e eventos climáticos extremos relacionados ao calor e ao frio no estado do Rio Grande do Sul- Brasil

Pós-graduação em Geografia - FCT

Circulação atmosférica e precipitação pluviométrica na Bacia do Itajaí - SC: um estudo climatológico aplicado

The work is guided by the detailing of the Itajaí river basin, SC, rainfall dynamics at the annual, seasonal and monthly levels, allowing us to identify different responses that each location gives to the regional atmospheric circulation, particularly the rainfall. In this sense, we are aiming at approaching the concept of rhythm, which must be obtained at the daily level. The analysis at different climate scales was possible through isohyetal maps, trend lines, and Schroeder pluviographs. Moreover, we established the flow rate of the air masses by means of the Venn diagram. This data made it possible to assess the behavior of rains on that site and the reason why it is the stage of major flooding, as occurred in November 2008. The relatively mountainous topography combined with the frequent invasions of the Atlantic Polar Front, which often stop over the region, generate events of that magnitude, with high volumes accumulated in short periods of time. Such extreme events reinforce the idea of the search for the succession of types of weather to the detriment of averages that tend to abstract the reality

Indicador de vulnerabilidade agropecuária a extremos climáticos para o nordeste do Brasil

The effects of climate change on human societies have become the focus of many researchers for their research. Understanding weather patterns (circulation of the atmosphere, precipitation, temperature) is essences for predicting extreme weather, but analyze how these extreme events act in our society and look for ways to reduce the impact caused by these events is the great challenge. Using a concept very in the humanities and social sciences to understand these impacts and the adaptation of the society's vulnerability. The objective of this work is to develop and apply a methodology for evaluating fining scale and quantify the vulnerability of the Brazilian Northeast to climatic extremes, developing a methodology that combines aspects of vulnerability to drought, as well as socioeconomic and climatic indicators used to assess exposure, ability to adaptation and the sensitivity of geographical microregions of the region. The assessment of the susceptibility or degree of exposure to risk is the regional using the SPI (Standardized Precipitation Index) by the degree of magnitude dried (MD), the rate of precipitation such as PCD (Precipitation Concentration Degree) and PCP (Precipitation Period Concentration) helped characterize and regional climatology, these indices showed satisfactory results in the pilot study of Rio Grande do Norte to assess the degree of exposure to drought. Regarding sensitivity agricultural / livestock multivariate statistical technique to factor analysis showed acceptable results for the proposed model using data for the period 1990-1999 (P1). The application of the analysis of vulnerability considering the adaptive capacity, as the adaptive disability have almost similar results with much of the region's vulnerability to extreme south of Bahia state as a part of the semiarid region has a degree of vulnerability among moderate and mean

Influência de eventos hidrológicos extremos na qualidade da água de reservatórios na região tropical semiárida

Reservoirs are artificial ecosystems, intermediate between rivers and lakes, with diferent morphological and hydrological characteristics that can provide many important benefits to society. However, the use of this water for human consumption, watering livestock, leisure, irrigated agricultural production and pisciculture development, directly influence the increase loading of nutrients to aquatic environments and contribute to acceleration of eutrophication. Furthermore, global climate models are predicting a higher occurrence of extreme events such as floods and severe droughts, which will create hydrological stresses in lakes. In the semiarid northeast we can see the occurrence of these events, the drought of the years 2012, 2013 and 2014 was the worst drought in 60 years, according to the National Water Agency (ANA). Thus, this study aimed to evaluate the quality of the semiarid tropical water sources, identifying temporal patterns in periods with extreme hydrological events (floods and severe droughts). The study results showed that Gargalheiras and Cruzeta reservoirs presented significative changes in the limnological variables between rain and severe drought periods, with better appearance and in the most of the water quality variables in the rainy season and higher nutrientes concentrations and high electrical conductivity values in severe season, indicating decay of its quality. However, we found diferent behaviors between the reservoirs in severe drought. While Gargalheiras showed a typical behavior of the region, with high concentrations of algal biomass, indicating the worsening eutrophication, Cruzeta demonstrated a colapse in the total phytoplankton biomass, evidenced by the decrease in chla concentrations. This fact occurred because the low depth and proximity with the sediment facilited the inorganic solids resuspension and, consequently, resulted in turbid water column and light by limitation. In addition, the different behaviors between the reservoirs indicate that the responses of these environments problems such as extreme events must take into account factors such the region climate, size, depth of the reservoir and the basin characteristics.

Calibração de um modelo hidrológico SWAT para a bacia hidrográfica da Ribeira de Quarteira

O Algarve é uma região que apresenta algumas particularidades no que toca às necessidades hídricas e respetiva disponibilidade. O consumo de água é relativamente elevado e as necessidades hídricas são mais elevadas nos meses de Verão quando a precipitação é escassa. Deste modo é de grande importância a realização de uma boa gestão dos recursos hídricos de modo a garantir a sustentabilidade dos recursos naturais. Neste âmbito surge a aplicação de softwares de modelação hidrológica que permitem realizar prognósticos simulando as condições a que o meio está sujeito. Na presente dissertação pretende-se aplicar o modelo SWAT para modelar as condições atuais registadas na bacia hidrográfica da Ribeira de Quarteira. Pretende-se também realizar a modelação de cenários de alterações climáticas previstas para dois períodos futuros: 2020-2050 e 2069-2099. A construção do modelo foi realizada em ArcSWAT, a análise de outputs foi feita em SWAT_Check e para a calibração e validação do modelo utilizou-se o software SWAT-CUP4. Os resultados obtidos na calibração e validação são relativamente satisfatórios tendo em conta a fraca qualidade e quantidade dos dados de entrada disponíveis e considerando-se o meio geológico cársico onde se pretendeu realizar a modelação. Os cenários simulados tiveram como base dois modelos climáticos realizados no âmbito do projeto CLIMWAT (ICTP-REGCM3 e CNRM-RM5.1). Os resultados de ambos modelos apontam para um aumento de temperatura e diminuição generalizada de precipitação que têm como consequência um aumento significativo de evapotranspiração real e uma diminuição muito grande de recarga profunda e do caudal instantâneo. Um dos modelos aponta para, no período 2020-2050, um aumento de eventos extremos (secas e cheias). Estas previsões vêm reforçar a grande necessidade de uma boa gestão dos recursos hídricos.

Estimativa da probabilidade do evento extremo de precipitação de janeiro de 2000 no Vale do Paraíba, baseada na distribuição generalizada de pareto

Um evento extremo de precipitação ocorreu na primeira semana do ano 2000, de 1º a 5 de janeiro, no Vale do Paraíba, parte leste do Estado de São Paulo, Brasil, causando enorme impacto socioeconômico, com mortes e destruição. Este trabalho estudou este evento em 10 estações meteorológicas selecionadas que foram consideradas como aquelas tendo dados mais homogêneos do Que outras estações na região. O modelo de distribuição generalizada de Pareto (DGP) para valores extremos de precipitação de 5 dias foi desenvolvido, individualmente para cada uma dessas estações. Na modelagem da DGP, foi adotada abordagem não-estacionaria considerando o ciclo anual e tendência de longo prazo como co-variaveis. Uma conclusão desta investigação é que as quantidades de precipitação acumulada durante os 5 dias do evento estudado podem ser classificadas como extremamente raras para a região, com probabilidade de ocorrência menor do que 1% para maioria das estações, e menor do que 0,1% em três estações.