Instability of thin, freshwater layers in the Bay of Bengal

Jonathan D Nash1, Jennifer A MacKinnon2, Andrew Pickering3, Emily Shroyer4, Drew J. Lucas5, Amit Tandon6, Amala Mahadevan7, Debasis Sengupta8 and Kevin Alexander Tennyson3, (1)Oregon State University, College of Earth, Ocean, and Atmospheric Sciences, Corvallis, United States, (2)University of California San Diego, La Jolla, CA, United States, (3)Oregon State University, Corvallis, OR, United States, (4)Oregon State Univ, Corvallis, United States, (5)University of California San Diego, Scripps Institution of Oceanography, La Jolla, United States, (6)University of Massachusetts Dartmouth, School for Marine Science and Technology, New Bedford, United States, (7)Woods Hole Oceanographic Institution, Woods Hole, MA, United States, (8)Indian Institute of Science, Centre for Atmospheric and Oceanic Sciences, Bangalore, India
Abstract:
Heavy precipitation and high river flow in the northern Bay of Bengal creates extremely thin freshwater layers that trap heat and alter air-sea fluxes. During the 2015 summer monsoon, an intensive joint US-Indian effort was undertaken to understand the horizontal and vertical dispersion of these layers. Within that program, repeat surveys of the very near surface velocity and stratification were simultaneously obtained by 2 ships and a remotely operated kayak, obtaining data with 1-m horizontal and vertical resolution of a large-scale front that remained persistent over several inertial periods. Here we focus on details of the frontal structure in the upper 10 m, exploring (i) the turbulence and instabilities with horizontal scales of 20-2000 m that act to diffuse it, and (ii) larger scale convergence that acts to maintain it. We will try to understand the factors that differentiate periods of intense instability from periods without.
Back to: From Monsoons to Mixing: Coupled Ocean-Atmosphere Processes and Biogeochemical Response in the Indian Ocean I