Impacts of different types of El Nino and La Nina on northern tropical Atlantic sea surface temperature

摘要

The present study investigates the dependence of the northern tropical Atlantic (NTA) sea surface temperature (SST) response to El Nino and La Nina events on the decay time and amplitude of tropical Pacific SST anomalies. It is found that the NTA SST response to La Nina events displays a notable difference between late and early decaying events, similar to that in response to El Nino events, but with a weaker signal. Latent heat flux is a dominant term in the NTA SST change in preceding winter-early spring in both El Nino and La Nina events and in the difference of the NTA SST anomaly between late and early decaying El Nino and La Nina events. The zonal and meridional advections have an opposite effect on the NTA SST warming in late decaying El Nino events. Although the warming in the NTA region is similar in late decaying moderate and strong El Nino events, the distribution of the SST anomalies in the mid-latitude North Atlantic Ocean shows a notable difference between the two types of late decaying El Nino events. The SST anomalies also display difference in the early decaying weak and moderate El Nino events. Surface heat flux differences are largely attributed to wind differences.