Seminar: The Fujiwhara Effect on the Enlarging Phytoplankton concentration in Southeastern Tropical Indian Ocean (SETIO) Region

Abstract:

A rare event known as Fujiwhara effect occurred in the southeastern tropical Indian Ocean (SETIO) when tropical cyclone (TC) Seroja and TC Odette were co-exist, interact each other, and merged into one TC in April 2021. Here, we used remotely sensed data [winds, sea surface temperature (SST), pressure, salinity, and chlorophyll-a concentration] and in situ data from meteorology stations and Argo floats to understand the impacts of Fujiwhara effect. Ekman transport and Ekman pumping velocity are calculated to quantify the upwelling strength. During the entire development of the TCs to the merging, the TCs induced upwelling through Ekman dynamics which enhanced the SST cooling (~3°C) and raising sea surface chlorophyll-a (~2 mg/m³) and shallowing the thermocline up to 10 m. The research on this rare event will add complexity of ocean and climate dynamics of the region as exit gate of the Indonesian throughflow to the Indian Ocean and may have implications to circulation and climate in the Indian Ocean and beyond.