Overview of regional climate modeling over South America. “The Meeting of the Americas

SOLMAN SILVINA ALICIA

Foz de Iguazú, Brasil

Conferencia; The Meeting of the Americas American Geophysical Union; 2010

American Geopgysical Union

Climate over South America is largely determined by the interaction among the large scale circulation and regional / local forcings in a broad range of timescales, from sub-daily to multidecadal. Regional forcings are mostly  associated with topography and regional thermal sources. The most important feature of the regional geography is the complex Andes chain, which extends all along the western coast and is characterized by a narrow barrier channeling the flow in the central part of the region. In consequence, in order to simulate the regional climate over the South American continent it is necessary to simulate adequately the regional forcings and the interaction between these forcings with the large-scale circulation. Regional climate simulations  over South America are relatively few and most of the studies have been devoted to 1) evaluate the capability of regional models to represent the main characteristics of the regional climate and 2) evaluate the impact of external forcings on the regional climate. The studies devoted in reproducing the main characteristics of the regional climate focus not only in indentifying systematic errors and uncertainties in the regional simulations but also in recognizing major shortcomings in the models which are possible tracks for model improvement. Studies devoted to evaluate the regional response to external forcings, such as increasing anthropogenic gas concentrations or land use changes, allow in first place, evaluating impacts of global climate change and land use change on regional weather, climate and hydrology over  South America and, in second place, identifying regions in which these impacts can be significant. This presentation summarizes in first place, the main features of regional climate over South America and the regional climate modeling ongoing efforts for the region. The focus will be on major achievements and shortcomings of regional climate modeling over South America. In second place, results of studies focused on the impact of external forcings on the regional climate will be presented in order to discuss areas that can be most affected. Finally, challenges for future work will be discussed.