ITF and Poleward Heat Transport of Indian Ocean

Abstract

A sigma coordinate model is used to study the heat transport variability and the influence of Indonesian Throughflow (ITF) heat transport on the Indian Ocean. The vertical mixing coefficients were provided by the turbulence scheme. The horizontal mixing coefficients for momentum (viscosity) and tracers (diffusivity) were calculated by a Smagorinsky-type formulation. The model is initialized with the Levitus94 climatological data set for annual mean temperature and salinity fields and is forced by seasonal and yearly varying da Silva SMD 1994 and Hellerman and Rosenstein (1983) wind data set. The spin-up of the model has been carried out separately for open and closed. The ITF transport is found around 10 Sv (Svedrup) (1 Sv = 10⁶ m³/s), and the heat transport across the equator is found at its maximum amplitude 1.3 PW (Peta Watt) (1 PW = 10¹⁵ Watts) in March and −1.6 PW in July. It is found that the overall effect of the ITF heat transport on the Indian Ocean is dominant on the south of 10°S, and this has a small effect between equator and 10°S.

Keywords:

• Heat budget
• continental shelf
• primitive equation
• interannual variability

Acknowledgements

We thank Dr. Tal Ezer, Princeton University, Princeton, New Jersey, USA, and in India Prof. A.D. Rao, IIT Delhi, Delhi; Dr. R. Krishnan, IITM Pune, Pune; Dr. Arun Chakravorthi IIT Kharagpur, Kharagpur; and Dr. M.S. Srinivasan, BHU, Varanasi for their encouragements and valuable suggestions. The authors also thank NCAOR/MoEs for financial assistance.