Global patterns of ENSO-induced precipitation

Although there have been many analyses of El Nino/Southern Oscillation (ENSO) induced precipitation anomalies, global patterns from these analyses remain incomplete. Here we combine recent satellite estimates of oceanic precipitation and historical rain-gauge records to derive a global climatology of ENSO-induced precipitation anomalies using empirical orthogonal function (EOF) analyses. The patterns suggest that the re-arrangement of convection centers of the Walker circulation during ENSO events induces large precipitation anomalies in the tropics, while associated changes in the monsoon systems (through the Hadley cell) over the Pacific, Indian and Atlantic Oceans, and their interactions with midlatitude westerlies generate coherent anomaly patterns over the extratropics. Our results can be used to evaluate climate models and forecast ENSO-induced precipitation anomalies.