Seasonal Driven Mechanism of the Surface Chlorophyll-A Distribution along the Western Coast of Sumatra

Abstract

The chlorophyll-a (chl) abundances on the Fisheries Management Area of Indonesia Republic (WPP-RI 572), as fishery resources over the western coast of Sumatera (WSC) and Sunda Strait, were examined in this study. The extensive investigation on the mechanism ocean dynamics on chl variability along WSC was observed by using remotely sensed data on the surface. The spatial analysis was conducted using the Moderate Resolution Imaging Spectroradiometer (MODIS) Aqua Ocean colour data for a period of January 2003 to December 2015. On seasonal time scale, the surface chlorophyll-a (schl) concentration in the southern tip of Sumatra is higher than the schl in the northern tip of Sumatra. Our results found that the schl concentration in the southern tip of Sumatra increases (decreases) during the southeast (northwest) monsoons. Interestingly, its interactions with the southeast monsoon wind result in intensify enhanced coastal upwelling along the monsoon trough in July – August. It triggered a large bloom of schl concentration from the upwelling region of southern tip Sumatra. Moreover, the schl in the center region followed the peak of the equatorial wind during the period transition in the Indian Ocean which is controlling the dynamics ocean such as upwelling event. Meanwhile, opposite situation of the schl concentration observed low along the western coast of Sumatra during the northwest monsoon. At the same time, strong upwelling observed at the northern tip of Sumatra were associated with intense cooling on the sea surface temperature. It triggered a large bloom of high schl a water from the upwelling region of northern Sumatra Island.

Keywords

• coastal
• equatorial wind
• modis
• sumatra
• surface chlorophyll-a