Simulating soil-precipitation feedbacks in South America

MENÉNDEZ CLAUDIO GUILLERMO; SÖRENSSON ANNA AMELIA; SAMUELSSON PATRICK; WILLÉN ULRIKA; HANSSON ULF

Nadi, Fiji

Workshop; IPCC/TGICA Expert Meeting on Integrating Analysis of Regional Climate Change and Response Options; 2007

Intergovernmental Panel on Climate Change

We resume the recent progress in regional climate modeling in South America using the Rossby Centre regional atmospheric climate model (RCA3), with emphasis on soil moisture processes. Five different sets of climatological integrations using a continental scale domain nested in reanalysis data were carried out. In the first two sets of simulations, the goal was to assess the model’s skill to simulate the annual mean climatology and particular two-month-long cases as part of the model intercomparison performed in the framework of the CLARIS project. The role of including a spatially varying and deeper soil depth in the model is then analyzed. The fourth experiment addresses the influence of anomalous soil moisture initial conditions on the intraseasonal development of the South American Monsoon System. A fifth set of simulations was performed to further explore the land-atmosphere coupling strength. In these simulations the austral winter soil moisture initial condition has a strong influence on wet season rainfall over the continental convective monsoon regions and subtropical South America appears as a region with relatively high coupling strength during the mature phase of monsoon development.