Open AccessUpper ocean responses in the central western equatorial Indian Ocean During the southwest monsoon season
Author(s) -
G. JOSEPH M,
Praveen Kumar,
P. Madhusoodanan
Publication year - 1996
Publication title -
mausam
Language(s) - English
Resource type - Journals
ISSN - 0252-9416
DOI - 10.54302/mausam.v47i1.3677
Subject(s) - mixed layer , thermohaline circulation , climatology , wind stress , monsoon , ocean heat content , geology , forcing (mathematics) , advection , buoyancy , subtropical indian ocean dipole , oceanography , atmospheric sciences , physics , thermodynamics , quantum mechanics
Upper ocean (200 m) response under the pre-onset, and active regimes of southwest (SW) monsoonal forcing at 0°N. 60°E in the Indian Ocean was analysed utilising time series data collection during Indo-Soviet Monsoon Experiment, 1973 (ISMEX- 73). Oceanic response under the pre-onset domination of the wind stress momentum and onset domination of buoyancy flux (B0) was apparent in shoaling/warming and deepening/cooling (12 m/0.50 C in 4 days) of Mixed Layer Depth (MLD). The pre-onset increase was followed by an onset decrease in below layer thermohaline/density gradient and disappearance of Sub-surface Salinity Maximum (SSM). Corespondingly, MLD and its heat content (HCMLD ) were more correlated to (B0) and QN . Upper ocean response during active regime manifested in deepening/colling (20 m/1C in 6 days) of MLD under dominant production of turbulent kinetic energy by wind stress except for the convectively dominant mixing at the beginning and end. With reduction in below-layer thermohaline/density gradient and absence of SSM the correlations between MLD B0 wind stress, QN and HCMLD became insignificant due to increased advective flux during active regime. One dimensional simulation of mixed layer paramerters showed agreement.