Future changes in the mean climate of the tropical Pacific and characteristics of the El Niño Southern Oscillation (ENSO) are established as being likely. In this work we determine the time of emergence of climate change signals from the background natural variability. We find that the annual-mean sea surface temperature (SST) signal across the whole tropical Pacific has already emerged, but appears latest in the east, where the background noise is high. The signal of a wetter annual-mean rainfall in the east Pacific is expected to emerge by mid-century, with some sensitivity to emission scenario. However, the signal of ENSO-related rainfall variability is projected to emerge by about 2040 regardless of the emission scenario followed. This is about 30 years earlier than ENSO-related SST variability signal. These results are discussed in the light of recent observed trends in SSTs in the tropical Pacific. We also discuss changes in ENSO  teleconnection patterns, i.e. the way that ENSO impacts climate around the world.

Le séminaire se tiendra le lundi 19 juin à 16h, dans la salle de réunion du LOCEAN, couloir 45-55, 4ème étage, pièce 417, campus Jussieu.