Division of Mechanical Sciences
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Title : The ocean beneath a hole in the monsoon: Results from the BoBBLE (Bay of Bengal Boundary Layer Experiment) (Click here for the Poster)
Speaker : Prof. P. N. Vinayachandran, CAOS, IISc, Bengaluru
Day, Date and Time : Thursday, 28th January 2020 at 4 pm
Prof. Govindan Rangarajan Director, IISc will preside
Abstract : The Bay of Bengal (bay) plays a fundamental role in controlling weather systems that make up the Asian summer monsoon system, including monsoon depressions and tropical cyclones. The southern bay has cooler sea surface temperatures (SST) that influence ocean-atmosphere interaction and impact the monsoon. The Indian Summer Monsoon is marked by a minimum in its seasonal rainfall in the southern bay. This hole in the monsoon is located above a relatively cold pool of water that surrounds the southern tip of India, Sri Lanka, and the southwestern bay. Besides, the ocean in this region is characterized by a cyclonic gyre with doming of the thermocline called the Sri Lanka Dome, chlorophyll blooms, a salt pump, and the intense Summer Monsoon Current that flows from the Arabian Sea into the baycarrying a sub-surface high salinity core. To understand the underlying mechanism of these oceanographic features, the Bay of Bengal Boundary Layer Experiment (BoBBLE) was carried out during the summer monsoon (June–July) of 2016, on board RV Sindhu Sadhana. Physical and biogeochemical observations were made using a conductivity–temperature–depth (CTD) profiler, five robotic ocean gliders, an Underway CTD (uCTD), a vertical microstructure (turbulence) profiler (VMP), two Acoustic Doppler current profilers (ADCPs), Argo floats, drifting buoys and meteorological sensors. Key results obtained from the data collected during the BoBBLE field experiment will be presented in this talk. These include barrier layer formation and erosion, the dynamics of Summer Monsoon Current, closure of mixed layer heat budget, mechanisms of deep chlorophyll maximum, and double-diffusive salt fingering.
About the Speaker : P. N. Vinayachandran obtained his M.Sc.(Engg.) and Ph. D. degree from the Indian Institute of Science, Bengaluru. Vinayachandran specialises in the development and applications of ocean general circulation models for physical and biogeochemical studies as well as for forecasting of the Indian Ocean. He also has expertise in designing and conducting process-based ship-board field experiments. He takes an active role in international science planning in the field of oceanography as a member of the steering committees of IIOE-2 (International Indian Ocean Expedition – 2), (SIBER) Sustained Indian Ocean Biogeochemistry and Ecosystem Research and Co-chair of OceanPredict Science Team.
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