Land–atmosphere coupling in El Niño influence over South America

Abstract

This study addresses the role of soil moisture and its interaction with the overlying atmosphere in setting up climate anomalies over South America during El Niño years using observations as well as Atmospheric General Circulation Model (AGCM) simulations. It is found that during summertime land–atmosphere interaction is instrumental in setting the spatial pattern and sign of surface air temperature anomalies, and increases substantially the amplitude of precipitation anomalies particularly in southeastern South America. Thus, in order to improve the seasonal forecasts over South America it is necessary to represent properly not only the teleconnection processes but also the regional land–atmosphere interactions.