Numerical study of the effects of ocean color on the sea surface temperature in the southeast tropical Indian Ocean: the role of the barrier layer

Abstract

The effects of biological heating on upper ocean temperatures in the southern tropical Indian Ocean region during the boreal summer were investigated by comparing the results of two modeling experiments using a solar radiation penetration scheme with and without chlorophyll effects. During the southeastern monsoon season, an increase in the chlorophyll concentration leads to cold anomalies off Java but warm anomalies off Sumatra. This contradictory effect is primarily caused by the difference in the barrier layer (BL) thickness in the two regions. Although the increasing phytoplankton tends to warm the surface and cool the subsurface in both regions, the existence of a thick BL in the region off Sumatra prevents cold anomalies from reaching the surface mixed layer (ML), whereas the thin BL off Java is favorable for the upwelling of cold subsurface anomalies into the surface ML, nullifying the warming effect of the increasing chlorophyll concentration.