Observed intraseasonal variability of mini-cold pool off the southern tip of India and its intrusion into the south central Bay of Bengal during summer monsoon season

The observed evolution of a mini-cold pool (MCP) off the southern tip of India (STI) and its intrusion into the south central Bay of Bengal (BoB) during the summer monsoon season shows pronounced cooling episodes on intraseasonal time scale with differences in their number, intensity, duration and spatial extent. This variability that changes from year to year appears to be primarily determined by the corresponding variability in the upwelling driven by the divergence in the near-surface (Ekman + geostrophic) circulation and wind induced mixing. The signature of this cooling carried by the Summer Monsoon Current (SMC) is seen with reduction in intensity in the south central BoB limited mostly only to south of about 10 degrees N. In the background of slow cooling caused by SMC, the cooling episodes of different amplitudes occur in the south central BoB suggesting that spatially variable wind forcing is responsible for producing these episodes simultaneously on intraseasonal time scale.