JpGU-AGU Joint Meeting 2017

Presentation information

[EE] Oral

A (Atmospheric and Hydrospheric Sciences) » A-CG Complex & General

[A-CG45] [EE] Multi-scale ocean-atmosphere interaction in the tropical Indo-Pacific region

Sat. May 20, 2017 9:00 AM - 10:30 AM 302 (International Conference Hall 3F)

convener:Motoki Nagura(Japan Agency for Marine-Earth Science and Technology), H Annamalai(University of Hawaii at Manoa), Ayako Seiki(Japan Agency for Marine-Earth Science and Technology), Yukiko Imada(Meteorological Research Institute, Japan Meteorological Agency), Chairperson:Motoki Nagura(Japan Agency for Marine-Earth Science and Technology), Chairperson:Ayako Seiki(Japan Agency for Marine-Earth Science and Technology)

9:00 AM - 9:15 AM

[ACG45-01] Coupled Physical Processes in the Bay of Bengal and Monsoon Air-Sea Interaction

★Invited papers

*Debasis Sengupta1 (1.Indian Institute of Science)

Keywords:Salinity, Near-surface stratification, Freshwater dispersal, Air-sea interation

The Bay of Bengal (BoB) receives about 4000 km3 of freshwater every year from summer monsoon rainfall and river discharge. The freshwater persists in the northern BoB for about three seasons, resulting in a near-surface stratified layer (usually less 30 m deep) with warm subsurface water. The meso-scale eddy flow and wind-driven shallow Ekman flow play major role in dispersing the riverwater in the Bay. The pathways of the riverwater can have significant year-to-year changes. The freshwater further strengthens the near-surface currents by squeezing the Ekman layer. As part of the OMM-ASIRI initiative, in the last four years we made intense fine-scale observations of near-surface temperature, salinity and currents in the north BoB from various platforms like moorings, research ships and other autonomous instruments including gliders, Lagragian floats. Our ship-based observations suggest presence of strong submesoscale (order 10 km) fronts, which could set the near-surface stratification by slumping the denser water under the light water. The shallow mixed layer influences the air-sea interaction on diurnal to subseasonal timescales. The monsoon active-break spells modulate the mixed layer depth, winds, air temperature and humidity just above the ocean surface. We discuss the relevence of these processes in observations and model simulations.