[A-OS12] Physical, biogeochemical, and ecological processes and variability in the Indian Ocean

[AOS12-P01] A study on the wind stress over marine atmospheric boundary layer in the Arabian sea

*Abhijith Raj^1,2, Praveen Kumar B¹, Raju Jampana¹, Pattabhi Rama Rao E¹, Suresh Kumar¹ (1.Ministry of Earth Sciences (MoES), Indian National Centre for Ocean Information Services (INCOIS), Hyderbad, India, 2.School of Ocean Science and Technology, Kerala University of Fisheries and Ocean Studies, Cochin, India,)

Keywords:Inertial dissipation method, marine atmospheric boundary layer , waves, Wind stress

Fast response wind data (20Hz) and meteorological parameters (1Hz) were collected during a 20-day cruise in the Arabian Sea using a bow-mounted sonic anemometer and an Automatic Weather Station (AWS) system. Wind stress on the sea surface were determined by inertial-dissipation method (IDM) over wide range of wind speed ranges as it does not require motion correction for ship induced motion. An examination of existing similarity functions was conducted, and a comparison was made between IDM estimates and bulk estimates of turbulent stress using the COARE 3.5 algorithm. The wind dependence of estimated drag coefficients were assessed. The inertial dissipation method yielded higher estimates than bulk values, owing to the presence of swell throughout the observation period. To address this overestimation, an imbalance function was introduced into the Turbulent Kinetic Energy (TKE) budget. Further analysis is being made for wind stress estimates under various wind angle with respect to ship bow