Author(s)

Sin Chan Chou^1*, André Lyra¹, Caroline Mourão¹, Claudine Dereczynski², Isabel Pilotto¹, Jorge Gomes¹, Josiane Bustamante¹, Priscila Tavares¹, Adan Silva¹, Daniela Rodrigues¹, Diego Campos¹, Diego Chagas¹, Gustavo Sueiro¹, Gracielle Siqueira¹, Paulo Nobre¹, José Marengo³

¹National Institute for Space Research, Cachoeira Paulista, Brazil.
²Department of Meteorology, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil.
³Centre for Monitoring and Warning of Natural Disasters, Cachoeira Paulista, Brazil.

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. Maximum temperatures are generally underestimated in the domain, in particular by MIROC5 driven simulations, in summer and winter seasons. Larger spread among the simulations was found in the minimum temperatures, which showed mixed signs of errors. The spatial correlations of temperature simulations against the CRU observations show better agreement for the MIROC5 driven simulations. The nested simulations underestimate precipitation in large areas over the continent in austral summer, whereas in winter overestimate occurs in southern Amazonia, and underestimate in southern Brazil and eastern coast of Northeast Brazil. The annual cycle of the near-surface temperature is underestimated in all model simulations, in all regions in Brazil, and in most of the year. The temperature and precipitation frequency distributions reveal that the RCM and GCM simulations contain more extreme values than the CRU observations. Evaluations of the climatic extreme indicators show that in general hot days, warm nights, and heat waves are increasing in the period, in agreement with observations. The Eta simulations driven by HadGEM2-ES show wet trends in the period, whereas the Eta driven by BESM and by MIROC5 show trends for drier conditions.

South America, Climate Downscaling, Model Evaluation, Climatic Extreme Indicators, Eta Model

Chou, S. , Lyra, A. , Mourão, C. , Dereczynski, C. , Pilotto, I. , Gomes, J. , Bustamante, J. , Tavares, P. , Silva, A. , Rodrigues, D. , Campos, D. , Chagas, D. , Sueiro, G. , Siqueira, G. , Nobre, P. and Marengo, J. (2014) Evaluation of the Eta Simulations Nested in Three Global Climate Models. American Journal of Climate Change, 3, 438-454. doi: 10.4236/ajcc.2014.35039.