Variations of mixed layer and upper ocean heat content of the North Indian Ocean using Argo floats

C. Kalyani Devasena K.V Ramesh
CSIR C-MMACS, NAL Belur Campus, Wind Tunnel Road
Bangalore-560 037, India
E-mail id: kalyani@cmmacs.ernet.in

The importance of the tropical ocean in influencing global climate is well understood. The Indian ocean, especially, the Arabian Sea is unique with its intense air-sea interaction and plays a very significant role in climate variability. For the climatic modeling studies precise mixed layer and thermocline observations are essential. In this study we describe high frequency variability of Mixed layer depth and heat content of the North Indian Ocean. First temperature and salinity profiles obtained from approximately 280 (covering the area 38-110E longitude and 10S-20N latitude) Argo profiles have been subjected to objective analysis (Ramesh and krishnan 2005) and derived the daily data, then interpolated to weekly data. This data ( which is spatially and temporally continuous after objective analysis) has been used to study the mixed layer variability and the thermocline variations of the Indian Ocean with special focus on Bay of Bengal, which is well know for its maximum rain
> >fall ( with a highest rainfall of The circulation and hydrography of the
> >Bay of Bengal is complex due to the interplay of semi-annually reversing
> >monsoonal winds and the associated heat and freshwater fluxes. Apart from
> >this, the inflow of warm high saline waters of the Arabian Sea, the
> >Persian Gulf and the Red Sea origin and a number of synoptic disturbances
> >(cyclones) originating during both pre-monsoon (May) and post-monsoon
> >(October) period also affects the upper ocean dynamics. We have compared
> >the new mixed layer depth derived from the argo profiles with that of
> >WOA-2002. The amplitude and seasonal changes of the mixed layer derived
> >from the argo floats differs from the previous climatological
> >observations. Further we have combined Argo data along with avialable
> >CTD and XBT observations of the Indian Ocean to study the heat content
> >variations of the Indian ocean for the years 2002-2005.