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To provide long-term simulations of climate change at higher resolution, Regional Climate Models (RCMs) are nested in global climate models (GCMs). The objective of this work is to evaluate the Eta RCM simulations driven by three global models, the HadGEM2-ES, BESM, and MIROC5, for the present period, 1961-1990. The RCM domain covers South America, Central America, and Caribbean. These simulations will be used for assessment of climate change projections in the region. 439Eta Model

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Uma climatologia preliminar da precipitação no município do Rio de Janeiro é elaborada utilizando-se 10 anos de dados observados na rede de 30 postos pluviométricos da Fundação Geo-Rio. A distribuição espacial do total pluviométrico anual médio mostra que os máximos concentram-se junto aos três maciços existentes na cidade: na Serra da Carioca (2200 mm) na Serra do Mendanha (1400 mm) e na Serra Geral de Guaratiba (1200 mm). Tais valores reduzem-se em direção às planícies, sendo um mínimo de 900 mm observado na Zona Norte da cidade. A estação Sumaré destaca-se por seus elevados índices pluviométricos durante todo o ano, especialmente em setembro quando a precipitação média mensal (297,5 mm) chega a ser cerca de sete vezes maior do que a dos postos localizados na Zona Norte. No Sumaré são observados em média 119 dias de chuva ao ano, enquanto, por exemplo, na Penha ocorre chuva em apenas 86 dias. A análise dos eventos de chuvas intensas indicou que 77% dos 160 casos selecionados, foram provocados por sistemas frontais, que ocorrem durante todo o ano, com menor freqüência no inverno. Eventos associados à Zona de Convergência do Atlântico Sul (13%) e sistemas convectivos de mesoescala (8%) predominam no verão. Chuvas intensas geradas por efeito de circulação marítima ocorreram em apenas 2% dos casos.

We analyse seasonal and annual trends of extreme indices of air temperature and precipitation over Brazil during the period 1961–2018. The main goal is to investigate whether the climate is changing and if so, to explore if there is any marked seasonality in such changes. The daily observed datasets of maximum and minimum temperatures, and precipitation, are provided by the Brazilian National Institute of Meteorology and National Water Agency. We use the Sen Curvature and Mann‐Kendall statistical tests to compute the magnitudes and to evaluate the statistical significance of climate extremes trends, respectively. The results show that the warm extremes frequency of occurrence is increasing significantly while the opposite occurs for cold extremes, which reveals a very consistent and widespread warming over Brazil. The highest increases in warm extremes occur during austral spring and summer while for the cold extremes the greatest decreases are observed during austral winter. Unlike temperature, precipitation extremes show heterogeneous signals for most of the country. In Northeast Brazil, there are changes towards a drier climate, especially in summer and autumn. In the Southern region, the climate is becoming wetter, with a reduction in consecutive dry days, especially in spring. For the other regions, there is no strong clear change sign, but both positive and negative precipitation extreme trends, without statistical significance (mostly in Southeast Region).

A study on the detection and future projection of climate change in the city of Rio de Janeiro is here presented, based on the analysis of indices of temperature and precipitation extremes. The aim of this study is to provide information on observed and projected extremes in support of studies on impacts and vulnerability assessments required for adaptation strategies to climate change. Observational data from INMET's weather stations and projections from INPE's EtaHadCM3 regional model are used. The observational analyses indicate that rainfall amount associated with heavy rain events is increasing in recent years in the forest region of Rio de Janeiro. An increase in both the frequency of occurrence and in the rainfall amount associated with heavy precipitation are projected until the end of the 21st Century, as are longer dry periods and shorter wet seasons. In regards to temperature, a warming trend is noted (both in past observations and future projections), with higher maximum air temperature and extremes. The average change in annual maximum (minimum) air temperatures may range between 2˚C and 5˚C (2˚C and 4˚C) above the current weather values in the late 21st Century. The warm (cold) days and nights are becoming more (less) frequent each year, and for the future climate (2100) it has been projected that about 40% to 70% of the days and 55% to 85% of the nights will be hot. Additionally, it can be foreseen that there will be no longer cold days and nights.

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