Impacts of Tropical Cyclone Seroja on the Phytoplankton Chlorophyll-a and Sea Surface Temperature in the Savu Sea, Indonesia
Riza Yuliratno Setiawan, R. Dwi Susanto, Anindya Wirasatriya, Inovasita Alifdini, Ardiansyah Desmont Puryajati, Lilik Maslukah, Nurjannah Nurdin
Abstract
The tropical cyclone (TC) Seroja is one of the rare climatic events in the Indonesian Seas, particularly in the Savu Sea. This unprecedented event, which matured on April 4, 2021, caused fatalities and severe damage to the region’s infrastructure and economy. High spatio-temporal resolution satellite measurements of surface winds, chlorophyll-a, and sea surface temperature (SST) are used to disentangle the impact of extreme wind speed (> 10 m∙s-1) on chlorophyll-a and SST. High wind speed associated with TC Seroja induced strong upwelling and vertical mixing in the Savu Sea, which led to phytoplankton blooms and SST depression. An abrupt change of daily variability and positive anomaly in phytoplankton chlorophyll-a concentrations reaches 13 mg∙m-3 and 0.3 mg∙m-3, respectively. At the same time, the SST shows significant cooling up to 3°C. Our results provide novel insights on the exceptional occurrence of a TC within the Indonesian Seas and highlight its impact on the surface ocean.