Uma avaliação preliminar de simulações climáticas de um modelo regional espectral aninhado em um modelo global (ECHAM4.5) sobre o setor norte da região nordeste do Brasil (1971-2000)

Abstract

This study presents a comparison of results between simulations (1971-2000) from a Global Atmospheric Model (ECHAM4.5 - Max Plank Institute) and a Regional Spectral Model (RSM) development in National Centers for Environmental Prediction - NCEP nested at ECHAM4.5, with emphasis in rainfall distribution to northern sector Northeast Brazil (NSNEB). The results had shown that for the total rain February to May (FM) on the NSNEB the ECHAM4.5 model showed a predominy of dry bias, and the RSM had presented systematic wet bias, except in the extremity north of the SNNEB where a dry bias was observed. In the most sector eastern of the SNNEB the MRE presented performance better, the systematic bias quality was lesser of that the observed in the simulation of the ECHAM4.5 for FM. O RSM overestimated the rainfall in may month over NSNEB, average 1971-2000, this characteristic not was observed in the ECHAM4.5. The RSM better had performance in simulating three and five categories of percentiles of rains (Very Dry, Dry, Normal, Rainy and Very Rainy) on the SNNEB. About the precipitation band associated the Intertropical Convergence Zone (ITCZ) over Tropical Atlantic Ocean, both models present similar configurations the get by Xie and Arkin sets to years considered with Normal, of La Niñas and of El Niños, even quantitatively o ECHAM4.5 get better performance. Comparisons of the atmospheric circulation in 1000 hPa from reanalysis of the NCEP/NCAR (National Center for Atmospheric Research) show configurations and intensities approximates, average 1971-2000, with the simulates by ECHAM4.5 and RSM, except the east of the 20o W whose simulations had show strong west winds not apparent in reanalysis.