A key step for any modeling study is to compare model-produced estimates with observed/reliable data. The original index of agreement (also known as Willmott index) has been widely used measure how well simulate observed However, in its version such may lead the user erroneously select a predicting model. Therefore, this compared sensibility two newer versions (modified and refined) provided an easy-to-use R-code capable calculating these three indices. First, indices was evaluated through...

Pre-whitening approaches have been widely used to remove the influence of serial correlations on Mann-Kendall trend test (MK_prew). However, previous studies indicate that this procedure may lead a false reduction significance trend. An alternative approach (MK_interact) has proposed improve assessment in auto-correlated data. Therefore, present study compared performance MK_prew and MK_interact for detecting trends series. Sets Monte Carlo experiments were carried out evaluate occurrence...

Drought is a slow-moving hazard that occurs in virtually all countries of the world. In light this, several indices have been developed to improve detection drought's onset, as well quantifying other features this phenomenon. The Standardized Precipitation Index (SPI) often used order characterize meteorological droughts. addition, index largely by Brazilian's agricultural institutions. add important information drought literature, review article described general definition drought,...

The Mann-Kendall test has been used to detect climate trends in several parts of the Globe. Three variance correction approaches (MKD, MKDD and MKRD) have proposed remove influence serial correlation on this trend test. Thus, main goal study was evaluate probability occurrence types I II errors associated with these three approaches. results obtained by means Monte Carlo simulations from a case allowed us drawn following conclusions: All are capable meeting adopted significant level when...

Abstract The standardized precipitation index (SPI) was developed as a stationary method in which the parameters of distribution used to estimate cumulative probability rainfall amounts do not vary over time. Considering that changing climatic conditions may violate assumption stationarity, nonstationary version SPI (NSPI) has been proposed. However, since time‐varying parametric distributions tend remove effect trends on NSPI estimates, this latter fail quantify severity drought events. In...

ABSTRACT The Standardized Precipitation Index was developed as a probability-based index able to monitor rainfall deficit in standardized or normalized way. Thus, the performance of this drought is affected by use distribution that does not provide an appropriate fit for data. goal study evaluate adjustment gamma amounts summed over several time scales (Pelotas, Rio Grande do Sul, Brazil), assess goodness-of-fit alternative distributions these series and normality assumption calculated from...

The intensification of drought incidence is one the most important threats 21st century with significant effects on food security. Accordingly, there a need to improve understanding regional impacts climate change this hazard. This study assessed long-term trends in probability-based indices (Standardized Precipitation Index and Standardized Evapotranspiration Index) State São Paulo, Brazil. Owing multi-scalar nature both indices, analyses were performed at 1 12-month time scales. calculated...

Abstract The main objective of this study was to investigate the trends on average and extreme events in time series daily precipitation from 1980 2010 Paraná River basin, Brazil. nonparametric Mann–Kendall test applied detect monotonic trend series. occurrence values analysed based three generalized (GEV) models: Model 1 (stationary), 2 (non‐stationary for location parameter), 3 scale parameters). GEV parameters were estimated by Generalized Maximum Likelihood method (GMLE) non‐stationary...

Abstract An essential step for improving climate change models' performance is to evaluate their ability represent the current conditions, especially extreme events. On such background, this study aims at evaluating of Quantile Delta Mapping (QDM) as a bias correction method annual maximum daily precipitation series (bmax) generated from downscaled models under tropical–subtropical conditions Brazil. We selected QDM due its correct in quantile wet days. Climate projections obtained 20 NASA...

The initial step in calculating the Standardized Precipitation Index (SPI) is to determine a probability density function (pdf) that describes precipitation series under analysis. Once this pdf determined, cumulative of an observed amount computed. inverse normal then applied probability. result SPI. This article assessed changes SPI final values, when computed based on Gamma 2-parameters (Gam) and Pearson Type III (PE3) distributions (SPIGam SPIPE3, respectively). Monthly rainfall series,...

The Mann-Kendall test has been widely used to detect trends in agro-meteorological as well hydrological time series.Trend-free pre-whitening (TFPW-MK) is an approach that improves the performance of this presence serial correlation.The main goal study was evaluate ability TFPW-MK nonlinear trends.As a case study, also applied 10-day values precipitation (P), potential evapotranspiration (PE) and difference between P PE (P-PE) obtained from weather station Ribeirão Preto, State São Paulo,...

Several studies have applied the Kolmogorov-Smirnov test (KS) to verify if a particular parametric distribution can be used assess probability of occurrence given agrometeorological variable. However, when this is same data sample from which parameters been estimated, it leads high failure reject false null hypothesis. Although Lilliefors had proposed remedy drawback, several still use KS even requirement independence between and estimated not met. Aiming at stimulating test, we revisited...

Considerando que algumas investigações sobre o tema aquecimento global utilizam longas séries temporais de temperatura uma questão deve ser levantada é relativa a influência possíveis concentrações fontes calor urbano os postos meteorológicos possam estar submetidos. O primeiro passo para responder essa verificar se, em mesma região, ocorrem tendências concomitantes elevação nos dados diversas localidades, possivelmente ligadas fenômenos escala global. Entretanto, se tiver seu início...

The aim of this study was to describe monthly series the Standardized Precipitation Index obtained from four weather stations State São Paulo, Brazil. analyses were carried out by evaluating normality assumption SPI distributions, spectral features these and, presence climatic trends in datasets. It observed that Pearson type III distribution better than gamma 2-parameter providing closer inherent use standardized index. time-frequency domain did not allow us establish a dominant mode...

ABSTRACT Enhancing the capability of both standardized precipitation index (SPI) and evapotranspiration (SPEI) for quantifying wet dry events under distinct climate conditions is paramount importance. The different recommendations recent studies regarding best distribution to calculate SPEI lack addressing effect parameters estimation methods on SPI motivated us apply adapt testing methodologies select candidate models calculating these drought indices (SDI). study based two data sets. first...

O objetivo do trabalho foi analisar tendências e/ou variações climáticas em oito séries de temperatura máxima média anual (Tmax), Estado São Paulo. Por meio testes paramétricos e não-paramétricos foram detectadas, nas localidades Pindorama Ubatuba, consideráveis elevações nos dados Tmax anos mais recentes dessas séries. Em contra partida, Cordeirópolis, Mococa, Monte Alegre Sul Ribeirão Preto, não verificadas alterações temporais significativas (elevação ou queda) Tmax. Nas Campinas...

O correto entendimento das diversas sucessões dos tipos de tempo, que podem ser observadas em uma região, é etapas fundamentais na redução do risco climático associado ao setor agrícola. objetivo trabalho foi analisar a variabilidade temporal dados mensais precipitação pluvial oito localidades Estado São Paulo. Investigações sobre possíveis tendências climáticas também foram realizadas. Por meio da análise ondeletas, teste razão máxima verossimilhança e Mann-Kendall, observa-se elevada...

O Índice Padronizado de Precipitação (SPI) é utilizado em programas estaduais e nacionais no monitoramento das condições seca diversas regiões brasileiras. Com base na hipótese que a análise longas séries temporais do SPI pode auxiliar adoção políticas mitigação combate essa anomalia climática, o objetivo desse trabalho foi analisar variabilidade mensal, localidade Campinas-SP, entre os anos 1890 2007. Por meio análises espectrais testes não paramétricos verificou-se uma escala três quatro...

Dados termopluviométricos são utilizados em diversos estudos. Contudo, a escassez de dados resultante da baixa densidade estações meteorológicas é um problema frequentemente encontrado. Com isto, utilização estimados por satélites tem-se mostrado importante para regiões nas quais eles escassos. Neste trabalho foram realizadas comparações entre mensais precipitação pluvial pelo satélite TRMM e temperatura, Aqua/MODIS aos observados superfície, diferentes localidades do Estado São Paulo, no...

Soil erosion, soil saturation and floods are frequently associated with extreme rainfall events. Thus, the scientific literature agrees on need to carry out studies that improve assessment of probability occurrence values. The main goal this study was compare performance multi-parameters distributions Wakeby, Kappa Generalized Extreme Value in fitting annual maximums daily, 2-day 3-day amounts obtained from weather station Campinas, located State São Paulo, Brazil (1890-2012). As a secondary...

Letícia Lopes Martinsa* , Wander Araújo Martinsa Iam Caio de Abreu Rodriguesa Ana Carolina Freitas Xavierb Jener Fernando Leite Moraesc & Gabriel Constantino Blaind a Post-graduation Program in Tropical and Subtropical Agriculture, Agronomic Institute, Campinas, Brazilb Water Resources, Vale Institute of Technology, Belém, Brazilc Soil Research Department, Brazild Ecophysology Biophysics Brazil

O objetivo do trabalho foi detectar tendências e variações climáticas nas séries mensais de temperatura máxima (Tmax) mínima (Tmin) Estado São Paulo. A fim obter melhor adequação, entre a probabilidade ocorrência dos erros estatísticos tipo I II, foram utilizados métodos paramétricos (teste t, F razão da verossimilhança) não sazonal Mann-Kendall Pettitt). As Tmin das localidades Campinas, Cordeirópolis, Ribeirão Preto e, especialmente Ubatuba, apresentam fortes indícios nos últimos 60 anos....

Regional climate models (e.g. Eta) nested to global HadGEM2-ES and MIROC5) have been used assess potential impacts of change at regional scales. This study the generalized extreme value distribution (GEV) evaluate ability two (Eta-HadGEM2-ES Eta-MIROC5) probability daily extremes air temperature precipitation in location Campinas, state São Paulo, Brazil. Within a control run (1961-2005), correction factors based on GEV parameters proposed approach distributions generated from those built...

The Pre-Whitening (PW), the Trend-Free (TFPW) and Modified (MTFPW) were developed to remove influence of serial correlations on Mann-Kendall trend test. main purpose this study was compare performance these algorithms for evaluating trends in auto-correlated series. PW, TFPW MTFPW also applied monthly values rainfall (Pre), minimum (Tmin) maximum (Tmax) air temperature data obtained from weather station Ribeirão Preto, State São Paulo, Brazil. Sets Monte Carlo simulations carried out...