Reconstructing 2012 and 2014 El Nino SSTA Development from Sub-seasonal Wind Events

Abstract:

The importance of Westerly Wind Events in the onset and development of El Nino events is now well established. Recently, we have shown that Easterly Wind Surges are also a prominent component of equatorial Pacific zonal wind stress variability, and that they play a role in La Nina development akin to that of Westerly Wind Events in El Nino. Here we examine how well the (partial) El Nino SSTA development observed in 2012 and 2014 can be understood in terms of sub seasonal wind events. We find that the observed 2012 and 2014 El Nino development can be accurately diagnosed by forcing a classic ocean general circulation model with a zonal wind stress field that we reconstruct based just on the application of wind events. The applied wind stress field is consistent with the available wind stress estimates to within the associated uncertainties, which are unfortunately larger than normal due to the collapse of the TAO buoy array over this period. These results suggest that improving our ability to predict ENSO SSTA development in years like 2012 and 2014 will require learning how to predict sub seasonal wind events