This article aims to evaluate the spatial distribution of the standard precipitation index (SPI) and the standardized form of the reconnaissance drought index (RDI_st) when applied to intense episodes of drought in the state of Rio de Janeiro (SRJ), Brazil. Data of 99 rainfall stations and 17 temperature stations collected during 31 consecutive years (1979–2009) were used to generate both drought indices, in the annual scale. Rainfall data faults were filled with normal climatological rainfall values provided by the Brazilian National Institute of Meteorology (INMET) in the period 1979–1997. The 3B43 product of the Tropical Rainfall Measuring Satellite (TRMM) data faults was used to fill up rainfall data faults during the period from 1998 to 2009. As for the temperature data, faults were completed based on the historical (1961–1990) average of the temperatures registered in stations within the same region. For the calculation of SPI and RDI_st indices in the annual scale it was used the computational tool Drinc (drought indices calculator). Spatial results were achieved using the spline tension method applied to the five most intense drought events (1984/1985, 1993/1994, 1997/1998, 1999–2000, 2002/2003 and 2007/2008) of the series, according to each index. The spline tension method presents satisfactory spatial consistency in the characterization of drought in SRJ. The results for indices SPI and RDI_st presented similarities in terms of spatial variation when applied to the SRJ, as the SPI demonstrated good characterization of drought severity with fewer data requirements.

Studies are scarce on the application of normality and homogeneity tests for rainfall series in the state of Rio de Janeiro, Brazil. Therefore, this study applies normality and homogeneity tests in a 71-year time series (1943–2013) of rainfall, seeking to identify which tests were most indicated in the evaluation of the normality and homogeneity of rainfall data in Rio de Janeiro. The tests of normality and homogeneity of variance were divided into (i) parametric—Shapiro-Wilk (SW) and Jarque-Bera (JB)—and (ii) non-parametric—Bartlett (B) and Fligner-Killeen (FK). All statistical procedures were performed using the open software R version 3.4.2. The tests of normality (SW and JB) and homogeneity of variance (B and FK) applied to the raw (unfilled) data showed that both the SW and JB tests were not satisfactory in determining the normality of the series, with only two stations reaching over 95% reliability. Regarding the homogeneity of variance of the standardized residues in the raw data, the B test stands out when compared to the FK test. After completing data faults of the data, the SW, JB, B, and FK tests pointed to rejection of the normality and homogeneity hypotheses for the specific time series. According to the adopted methodology, there are 15 useful stations (65.22%), 7 dubious (30.43%), and one suspicious (4.35%). The SW and B tests presented better results when matched to the other tests. The proposed methodology should be considered for further investigation of normality and homogeneity in other climate datasets.

O objetivo deste artigo é caracterizar a variabilidade espaço-temporal e interanual da chuva no Estado do Rio de Janeiro (ERJ) entre 1979 e 2009. Para isso foram utilizados dados de chuva de 99 estações pluviométricas, meteorológicas convencionais e automáticas distribuídas nas oito regiões de Governo do ERJ. As regiões de Governo com os maiores percentuais médios de falhas registradas foram Metropolitana, Costa Verde, Baixadas Litorâneas, Centro Sul, Médio Paraíba, Norte, Serrana e Noroeste. As falhas identificadas foram preenchidas com dados do produto 3B43 do satélite TRMM e com as normais climatológicas do INMET. A chuva média anual do período de estudo obtida para o estado foi de 1544 mm. As regiões Baixadas Litorâneas (2144 mm), Costa Verde (1912 mm), Médio Paraíba (1602 mm), Metropolitana (1571 mm) e Serrana (1547 mm) registraram média maior que a média estadual do período, enquanto as regiões Centro Sul (1307 mm), Noroeste (1235 mm) e Norte (1033 mm) ficaram abaixo da média. Todas as regiões registraram meses menos chuvosos em junho, julho e agosto. Já os meses com maiores totais de chuva foram registrados entre novembro e março, dependendo da região. A alta influência do relevo (altitude) no regime de chuva em todo o ERJ ficou caracterizada, principalmente nas Serras dos Órgãos e da Mantiqueira. As estações localizadas na vertente voltada para oceano Atlântico (barlavento) registraram as maiores médias anuais de chuva do estado, ao passo que regiões de relevo menos acidentado (Norte e Noroeste), ou com vertente voltada para continente (sotavento) das principais barreiras orográficas, registraram chuva média anual com valores inferiores à média estadual.