Nonlinear Impact of El Nino in South America

The global atmosphere climate signal related to El Nino and La Nina anomalies responses phases has generally been considered all over the world as a linear answer to each one of these phases. However, recently analyses of rainfall and temperature fields, particulary in North America show a nonlinear responses to El Nino/La Nina. The aim of this work is to open this question into South America climate analyses. It is used the CCM 3.6 (Community Climate Model) to perform an ensemble of the El Nino 91/92 event. The model is forced with a climatological SST and each perturbed ensemble member is obtained using a random error perturbation scheme. Time series of selected points over South America constructed for each member as well as the nonlinear part of geopotencial and convective activity shows different space/time distributions according to the position of the points and the type of the variable, indicating that the nonlinear counterpart has a considerable contribution into the climate anomalies responses related to an El Nino event over South America.