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Mechanism of intraseasonal oceanic signature in the region off southern tip of India during boreal summer

Jayakumar, A and Gnanaseelan, C and Sabin, TP (2013) Mechanism of intraseasonal oceanic signature in the region off southern tip of India during boreal summer. International Journal of Climatology, 33 (9). pp. 2280-2288.

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Sea surface temperature (SST) in the region off southern tip of India (STI, 75-83°E, 5-8°N) exhibited a prominent variability in the intraseasonal time scale (both 30-90 d and 10-30 d band) during boreal summer. Mechanisms associated with this intraseasonal variability are studied using three-dimensional ocean general circulation model (OGCM) sensitivity experiments, satellite observed outgoing longwave radiation, SST and winds for the period 1998-2007. The background oceanic structure of the STI characterized by a shallow thermocline and moderate mixed layer provided ideal conditions for strong oceanic sub-surface processes. The model mixed layer heat budget reveals that the oceanic processes such as horizontal advection and vertical processes are the dominant mechanisms in the STI region as compared with air-sea flux. Sensitivity experiments with the OGCM reveals that the ocean dynamical processes contribute to most of the intraseasonal SST variability and the wind stress contributes to 85 of the variability whereas surface flux contributes to only 15 for the 30-90 d SST variability. Higher amplitude of surface flux perturbation and its contribution to SST in the 10-30 d as compared with the 30-90 d band are evident in the model experiment and are consistent with the observational analysis. There is year-to-year variability in the relative role of horizontal and vertical processes for different intraseasonal SST events over STI.

Item Type: Article
Additional Information: Copyright of this article belongs to Royal Meteorological Society.
Uncontrolled Keywords: Ekman pumping; Intra-seasonal; Ocean general circulation models; Sub-monthly variability; Surface flux, Atmospheric temperature; Climate change; Experiments; Oceanography; Surface measurement, Semiconducting silicon, advection; air-sea interaction; Ekman pumping; heat budget; longwave radiation; mixed layer; oceanic general circulation model; sea surface temperature; summer; surface flux; thermocline; three-dimensional modeling; wind stress, India
Subjects: Meteorology and Climatology
Depositing User: IITM Library
Date Deposited: 17 Jun 2014 10:13
Last Modified: 17 Jun 2014 10:13

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