A modeling study of the effect of the Andes on the summertime circulation of tropical South America

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A simple linear two level model of the atmosphere is developed. By blocking the lower layer of the model with a meridional wall, the interaction between diabatic forcing centered in the Amazon basin and the Andes is studied. This forcing can be considered a source of Rossby waves that scatter from the above partial barrier. The scattering process is examined analytically by making the long-wave approximation. Numerical solutions without the long-wave approximation are then considered and the effects of the above scattering process are examined. the upper level circulation is shown to be qualitatively similar to that obtained without a barrier. The low-level circulation west of the barrier is weak in the winds and consists of a positive geopotential response centered at approximately 30°S. To the east, the circulation near the barrier shows similarity to models of the Somali jet. The model produces quite strong trade winds and places a low-pressure center in approximately the position where one is actually observed. -from Author

Original languageEnglish (US)
Pages (from-to)3344-3362
Number of pages19
JournalJournal of the Atmospheric Sciences
Issue number21
StatePublished - Jan 1 1989


ASJC Scopus subject areas

  • Atmospheric Science

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