Detection of monsoonal phytoplankton blooms in Luzon Strait with MODIS data

The Luzon Strait experiences a seasonal surge of phytoplankton based on ocean color data. To examine the timing and position of the bloom, daily MODIS chlorophyll data (2002–2005) were acquired and analyzed. Supporting data such as MODIS SST and nLw bands, QuikSCAT wind data, river discharge, and bathymetry were also used and processed in order to investigate the possible driving forces behind the bloom occurrence. Results show that chlorophyll concentration in the Luzon Strait dramatically increases during NE monsoon reaching to approximately 2.0 mg/m3. Highest chlorophyll concentration is observed near the western slope of the Luzon Strait. The monsoonal bloom in the Luzon Strait is likely due to upwelling and can be possibly associated with the interaction of the northward flowing Luzon coastal current with the westward intrusion of Kuroshio during NE monsoon. The positive wind stress curl also contributes to this occurrence. The influence of Cagayan River is only limited within few kilometers from the river mouth.