RELATIONSHIPS OF INTER-AMERICAN RAINFALL TO TROPICAL ATLANTIC AND PACIFIC SST VARIABILITY

Area-averaged anomalies of sea surface temperature (SSTA) and rainfall , developed from large scale data sets, have been used to explore the relative importance of Pacific versus Atlantic SST variability for int er-American (50 degrees S - 50 degrees N) climate variability at inter annual time scales. SSTA in the tropical Pacific and tropical North At lantic are comparably related to rainfall north of 15 degrees S, with clear associations distributed between the southeastern United States (US) in the north and northern South America in the south. Although NI NO3 explains 25% of the variance of the North Atlantic SSTA index, the rainfall correlations with North Atlantic SSTA are for the most part opposite in sign to those with NINO3. Hence, a significant part of the Atlantic SSTA probably has a direct association with rainfall, rather than being merely an indirect proxy for Pacific ENSO linkages. In con trast to the North Atlantic, South Atlantic SSTA appear to be only rel ated to rainfall in northeast (NE) Brazil. The entire region between V enezuela and NE Brazil appears to be sensitive to both the ITCZ and to antisymmetric configurations of SSTA across the ITCZ, in a manner con sistent with the relationships between SST, surface wind and surface w ind divergence fields, and with previous studies.