Utilization of
Satellite-Derived Salinity for Indian Monsoon Studies
Corinne Trott
University of South Carolina
9 Nov, Noon, in 2155
Abstract:
The Indian monsoon is a complex, nonlinear phenomenon involving
atmospheric, oceanic, and land-based interactions. Unfortunately,
despite decades of research and the aid of new observational and
modeling tools, monsoon forecasting remains insufficient and
challenging. Because it does not directly affect air-sea fluxes,
salinity is often neglected in climate-related studies, though recent
works have shown that regional salinity can play an integral role in
ocean-atmosphere interactions in the South Eastern Arabian Sea (SEAS)
region. The monsoon onset vortex, which is responsible for the
initiation of the summertime heavy rainfall over India, is triggered by
strong air-sea fluxes intensified by salinity-induced barrier layer
formation in the SEAS region, but the monsoonal rainfall intensity is
directly tied to the strength and northward propagation of
intraseasonal oscillations (ISOs) with periodicities of 30-90 days (MJO
events), 10-20 days (quasi-biweekly oscillation) and 3-7 days (synoptic
events). Evaluation of coupled models such as the Climate Forecast
System (CFS) version 2.0 reveals insufficient detection of ISOs when
compared with those detected by satellite-derived salinity from Soil
Moisture and Ocean Salinity (SMOS) and Soil Moisture Active Passive
(SMAP). Northward propagation of ISOs seen in SMAP sea surface salinity
modulates the post-monsoon (October-November) air-sea interactions in
the northern Indian Ocean, which and are a necessary component of
determining upper-ocean mixing conditions in the Arabian Sea that then
fuel monsoon onset for the next summer monsoon season. The usage of
satellite-derived salinity in coupled atmospheric-ocean models will
improve model simulations with respect to the influence of salinity on
monsoonal processes .