Oceanic Processes in Ocean Temperature Products Key to a Realistic Presentation of Positive Indian Ocean Dipole Nonlinearity
Kai Yang, Wenju Cai, Gang Huang, Guojian Wang, Benjamin Ng, Shujun Li
Abstract
Abstract A positive Indian Ocean Dipole (pIOD) refers to a sea surface temperature anomaly pattern with cold anomalies in the equatorial eastern Indian Ocean and warm anomalies in the west, leading to floods in the eastern African countries and droughts and bushfires in Indonesia and Australia. The pIOD displays strong inter‐event differences, ranging from an extreme event dominated by westward‐extended strong cold anomalies along the equator, to a moderate event with weakened cooling confined to region off Sumatra‐Java. Representation of the extreme pIOD varies vastly across ocean temperature products. Here we show that products generated in a system explicitly involving subsurface oceanic processes capture the nonlinear dynamics of the extreme pIOD, i.e., the equatorial nonlinear zonal and vertical advection, and systematically produce a more realistic extreme pIOD. Thus, our study identifies ocean temperature products that are more suitable for studying extreme pIOD and its climatic impacts.