Variabilidad de baja frecuencia sobre Sudamérica en el modelo COLA

C. VERA; J. NOGUES-PAEGLE; C. SAULO; G. SILVESTRI

Argentina

Congreso; IX Congreso Argentino de Meteorología; 2005

Centro Argentino de Meteorólogos

The principal patterns of variability in intraseasonal to interannual time scales over South America are examined to quantify the ability of the COLA model (version 3) to reproduce this variability. The model exhibits a strong response to ENSO that is not consistent with rainfall observations that indicate important contributions to the interannual variability over South America by sea surface temperature anomalies over the southern Atlantic. The model is not able to reproduce the maximum of precipitation over southeastern South America, or its variability. This is particularly detrimental to the simulation of the intraseasonal dipole of precipitation, characterized by poles over the SACZ and SESA. This limitation may be due to the model’s inability to simulate the propagation path of the ISO over the Pacific Ocean and the diurnal cycle over South America. The latter is relevant for ISO as intense rainfall events occur at daytime in the SACZ and at night over SESA.