Characteristics of Marine Heatwaves (2008–2021) in the Savu Sea, East Nusa Tenggara

Abstract

In this paper, we investigate the characteristics and the mechanism underlying the formation of marine heatwaves (MHWs) in the Savu Sea, known as the richest marine biodiversity area in the world. The focus is on identifying the frequency, intensity, and duration of occurrence MHWs generated by local forcing in the form of net surface heat flux. The study utilizes the remote sensing data from NOAA Optimum Interpolation (OI) Sea Surface Temperature (SST) for SST and The European Centre for Medium-Range Weather Forecasts Reanalysis v5 (ERA-5) for net surface heat flux components (shortwave radiation, longwave radiation, sensible heat flux, and latent heat flux). All data covers the period for the last 14 years (2008–2021) during the cold phase of the Pacific Decadal Oscillation (PDO) and then processed by statistical analysis methods. The results showed that the mean frequency, intensity, and duration of occurrence MHWs in the Savu Sea were around two times a year, 1.4–1.6 °C, and 10–12 days, respectively. The highest frequency and intensity MHWs occurred at around 122–124 °E and 8.30–9.30 °S (northern Savu Sea) generated by the most significant net surface heat flux in these areas. This study reveals the most dominant contribution of net surface heat flux in the northern Savu Sea comes from high shortwave radiation (heat gain) and low latent heat flux through the evaporation process (heat loss), thus keeping the ocean warm.