PHYSICAL DRIVERS OF THE 2013 MARINE HEATWAVE IN THE SEAS OF THE SOUTHERN JAVA-NUSA TENGGARA

Abstract

Marine heatwave (MHW) is an extreme phenomenon of warm sea surface temperature anomaly that has a destructive impact on the marine ecosystem and organisms. This phenomenon increases every year in duration, frequency, and area due to the global warming. Almost all of the world's oceans have experienced MHW, including in the seas of the southern Java-Nusa Tenggara. The lack of detailed research in this area motivated us to analyze MHW drivers. MHW was identified with the 99th percentile method and duration of ≥ 5 days as a threshold by using blended product of SST data. In 2013, an MHW event was identified in the seas of the southern Java-Nusa Tenggara. This MHW lasts for 37 days, from 8 June to 14 July. The maximum (mean) intensity of sea surface temperature anomaly reaches 2.60°C (1.83°C) above climatology with an average area of 36.53 × 104 km2. Locally, we found that probably the positive downward shortwave radiation affected this anomaly. Furthermore, a remote process of the propagation of downwelling Kelvin wave during negative Indian Ocean Dipole may also affect this anomaly. The strong westerly wind along the equatorial Indian ocean forms downwelling Kelvin wave that propagates to the southern Java-Nusa Tenggara increasing SST in this area.