Changes in timing of the South American Monsoon?

Abstract

The World Climate Research Program (WCRP) Coupled Model Intercomparison Project version 3 (CMIP3) dataset employed in this analysis of South American climate projections through the 21st century. Warm season rains associated with the South American Monsoon System (SAMS) are critical in the seasonally dry regions of Southeastern Brazil and the Bolivian Altiplano. Changes in the annual cycle of the SAMS are investigated by examining the 20th century model simulations against observations, and then evaluating differences between the projected mid (2030-2059) and late (2070-2099) 21st century climates with that of present day (1970-1999). Analysis emphasizes the annual cycle of temperature and precipitation, with an exploration of the mechanisms involved in changes including moisture transport, sea level pressure and low level winds, particularly the Andes low level jet.