Friday, October 04, 2019 at 10:30am to 11:30am
Narragansett Bay Campus, Corless Auditorium (Watkins Building) 215 S Ferry Rd, Narragansett
Join us for a Physical Oceanography Seminar from Dr. Amit Tandon of UMass Dartmouth titled, "Sub-mesoscale processes in the Bay of Bengal ."
Abstract: Two major observational efforts, ASIRI-OMM*, and MISOBOB-OMM* in the Bay of Bengal in the last six years have involved scientific teams from USA, India and Sri Lanka exploring process studies in the Bay of Bengal. After presenting an overview of these studies which I led, I will focus on lateral submesoscale processes and their influence on vertical stratification at shallow salinity fronts in the central Bay of Bengal during the winter monsoon using high-resolution data from a cruise in November 2013. The observations are from a radiator survey centered at a salinity-controlled density front, embedded in a zone of moderate mesoscale strain (0.15 times the Coriolis parameter) and forced by winds with a downfront orientation. Below a thin mixed layer, often ≤10 m, the analysis shows several dynamical signatures indicative of submesoscale processes: (i) negative Ertel potential vorticity (PV); (ii) low-PV anomalies with O(1–10) km lateral extent, where the vorticity estimated on isopycnals and the isopycnal thickness are tightly coupled, varying in lockstep to yield low PV; (iii) flow conditions susceptible to forced symmetric instability (FSI) or bearing the imprint of earlier FSI events; (iv) negative lateral gradients in the absolute momentum field (inertial instability); and (v) strong contribution from differential sheared advection at O(1) km scales to the growth rate of the depth-averaged stratification. The findings here show one-dimensional vertical processes alone cannot explain the vertical stratification and its lateral variability over O(1–10) km scales at the radiator survey.