Pre-monsoon Variability of Ocean Processes along the East Coast of India

• Published in: Journal of coastal research 2008-05, Vol.24 (3), p.628-639
• Main Authors: Babu, S. V., Rao, A. D., Mahapatra, D. K.
• Format: Article
• Language: English
• Subjects: Artificial satellites; Bathymetry; Bays; Coastal currents; coastal upwelling; Coasts; Density currents; Discharge; Modeling; Monsoons; Ocean circulation; Ocean circulation models; Ocean currents; Oceanography; Oceans; Physical properties; Rivers; Salinity; Sea surface temperature; Studies; Upwelling; Upwelling water; Wind; wind-driven circulation; winds
• ISSN: 0749-0208; 1551-5036
• DOI: 10.2112/06-0744.1

A three-dimensional Princeton Ocean Model has been configured for the east coast of India to study the circulation and coastal upwelling during the pre-monsoon season of 2000. The model uses an orthogonal curvilinear grid and a terrain-following sigma coordinate in the vertical with monthly data fields of temperature and salinity from “Levitus94.” The model is applied to study the coastal ocean processes and its variability on weekly timescales off the east coast of India. The forcing in the model is the real-time weekly averaged wind stress obtained from Quik Scattero-meter/National Center for Environmental Prediction blended wind of May 2000. The discernable variability in the winds of May 2000 over the weekly timescale influenced the surface layers reflected in the 3-day mean satellite images. To simulate this feature and to understand the dynamics, numerical experiments are carried out with the associated real-time winds. Both diagnostic and prognostic computations are used for this, and the model simulations off Paradip and Visakhapatnam are examined to study the variability of the processes on weekly timescales. he model-simulated sea surface temperatures in different experiments are in qualitative agreement with the available 3-day mean Tropical Rainfall Measuring Mission Microwave Imager satellite images. Apart from simulating the typical characteristic features, the model also could simulate the observed intense coastal current leaving the coast to form an eastward jet in the pre-monsoon season. The associated anomalous weaker circulation in the head bay can be attributed to the built-in opposing density currents developed in that region. The simulations suggest that the head bay is delineated from the rest of the bay in terms of its physical properties as well as physical processes.