Seasonal and intraannual mixed layer variability and its influence on Chlorophyll variations in an Ocean General Circulation Model (OGCM)

The Southern Ocean is considered to be a region with high inorganic nutrient concentrations and low phytoplankton biomass. This is one of the oceans which is least explored and is less accessible compared to other oceans. The motivation for this study is the judicious use of satellite data and ocean model advancements to examine the mixed layer variability in detail and its influence on the seasonal chlorophyll variations on interannual and intraseasonal time scales. In this study we have used the OGCM (latest version of GFDL MOM4p1, a coupled ocean ice model). Our aim is to study the seasonal sea ice thickness and SST variations on the mixed layer depth of the Southern Ocean. For this purpose We have used two sets of global model simulations using fluxes from two different sources, one from ERA-40 and another from NCEP reanalysis. We have used model simulations from 1960 to 2007 to study the thermal structure and mixed layer variations of southern ocean with special focus on ACC. The model simulated mixed layer depth and thermal structure are validated using a multi source data from satellite altimetery and insitu observations (from ARGO and WOCE). We have also studied the Sea Surface Height (SSH) anomalies and their influence on the seasonal chlorophyll variations for the period 2000-2007 using model simulations and observations. The heat and salt content variations inturn help us in understanding the seasonal chlorophyll variations along with eddy locations. We will present the details of the work in this conference