Pedro L. Silva Dias (1)
(1) Department of Atmospheric Sciences Institute of Astronomy and Geophysics University of São Paulo São Paulo SP Brazil
The low level circulation along the Andes is characterized by strong LLJ's (southerlies to the west of the Andes and northerlies to the east). The land/ocean contrast, superimposed on the topographical effect contribute to the intensification of the LLJ. Transient synoptic systems also interfere with the magnitude of the LLJ, either increasing or decreasing the intensity of the LLJ. Model evidences of the important control exerted by latent heat release, supported by observational data, are presented in this report. The model results are based on a series of experiments conducted with the Regional Atmospheric Modeling System (RAMS) with 5 km and 20 km resolution. Significant intensification of the northerly LLJ to the east of the Andes is observed when deep convection is formed along the slopes of the Andes or at the top. On the other hand, during the Southern Hemisphere Summer, weakening of the LLJ is observed when deep convection is present to the east of the Andes. The diurnal cycle of the LLJ is also substantially affected by the latent heat release. The compensating subsidence associated with the deep convection on top of the Andes spreads its influence over the eastern part of the Pacific, interacting with the stratiform
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