Análise das projeções de precipitação do IPCC-AR4 para os cenários A1B, A2 e B1 para o século XXI para Nordeste Setentrional do Brasil

Abstract

The precipitation projections of global models in the Fourth Report of the Intergovernmental Panel on Cli- mate Change (IPCC-AR4) are analyzed in Northern Northeast Brazil for the period from 2010 to 2099 in scenarios A1B, A2 and B1. For seasonal analysis we considered the average annual precipitation anomaly and the anomaly in average climatology scenarios over the 21st century compared to the 20th century. For analysis of interannual variations, we used an assessment of trends utilizing classical methods (moving average of 10 years, linear regression and Mann-Kendall-Sen) and wavelet analysis. The models show major pre-season impacts with a high scenario spread. This indicates a possible anticipation or postpone ment of ITCZ influence in the region. Most models indicate no significant trend for the interannual variations. The UKMO_HADCM3_run1 model has the most pessimistic projections for the 21 st century for three scenarios. The CNRM_CM3_run1 model indicates one of the biggest trends for increase in annual rainfall for the three scenarios. The trend shown by these models is partly explained by natural variation of low frequency of the series, but mainly an obvious change in rainfall in the series.