Impact of atmospheric submonthly oscillations on sea surface temperature of the tropical Indian Ocean

Impacts of atmospheric intraseasonal oscillations (ISOs) at submonthly periods ( 10 - 30 days) on Indian Ocean sea surface temperature (SST) are studied using satellite observed outgoing long wave radiation, QuikSCAT winds, SST and an ocean general circulation model for the period of 1999 - 2004. The results suggest that submonthly ISOs can cause significant 10 - 30 day SST changes throughout the equatorial basin and northern Bay of Bengal, with an amplitude of as large as 0.5 degrees C and standard deviation of exceeding 0.2 degrees C for a 4-year record. Impact of the submonthly ISO associated with the Indian summer monsoon is separately examined. It is associated with basin-scale SST evolution with distinct spatial structures. The SST variation results mainly from submonthly wind forcing, which causes changes in oceanic processes and surface turbulent heat fluxes. Radiative fluxes can also have large influences in some regions for some ISO events.