TITLE:
Evaluation of the Eta Simulations Nested in Three Global Climate Models
AUTHORS:
Sin Chan Chou, André Lyra, Caroline Mourão, Claudine Dereczynski, Isabel Pilotto, Jorge Gomes, Josiane Bustamante, Priscila Tavares, Adan Silva, Daniela Rodrigues, Diego Campos, Diego Chagas, Gustavo Sueiro, Gracielle Siqueira, Paulo Nobre, José Marengo
KEYWORDS:
South America, Climate Downscaling, Model Evaluation, Climatic Extreme Indicators, Eta Model
JOURNAL NAME:
American Journal of Climate Change,
Vol.3 No.5,
December
31,
2014
ABSTRACT: 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.