Simulated fluctuations of the hydrological regime over South-America at different time-scale

Precipitation over the Southern part of South-America is associated with large-scale meteorological patterns such as the SACZ or the moisture transport along the Andes, which display strong seasonal or intraseasonal fluctuations, but are also known to vary at a lower frequency, due to such influences as the ENSO, for exaple. The LMD GCM reproduces correctly the main elements of the precipitation climatology for the area under consideration. It is run in a forced mode (forced by observed SSTs) or in a coupled mode (the LMD GCM is the atmospheric component of the IPSL coupled GCM). We analyze pluridecadal simulations of the LMD GCM to document the simulated patterns of precipitation fluctuations, and their association to a frequency range (intraseasonal, interannual, interdecadal). Simulations in response to an increase CO2 will also be considered.