Water, heat and salt budget in the Indian Ocean.

摘要

The primary goal of the work proposed here is to quantify water mass, heat and salt budget in the northern Indian Ocean, characterize their seasonal to interannual variability in response to monsoon forcing and understand the processes that control the exchange and storage of water, heat and salt.; Estimates of the heat and salt budget computed using TOPEX/Poseidon (TIP) altimetry and hydrographic data (World Ocean Atlas; WOA98) are used to study the redistribution of heat and salt variability of the Indian Ocean. Significant seasonal and interannual variability was found in the Indian Ocean Sector. Except for the seasonal change in solar radiation and the rainfall, the major ocean processes that affect the heat and salt storage redistribution include monsoon-related upwelling and Ekman pumping, seasonal changes of ocean circulation, and propagation of Rossby and Kelvin waves. Significant interannual heat storage variability was found over an 8-year period (1993–2000).{09}EOF analysis shows that the first four EOFs explain nearly 60% of the total variance of the heat storage variability with the first mode of the heat storage variability indirectly related to the Indian Ocean Dipole. The dominant EOF mode for salinity explains 33% of the total variance of the salt storage variability in the Indian Ocean. This mode is attributed to the seasonal climate change between hemispheres.; The water, heat and freshwater fluxes out of the northern Indian Ocean are also computed for World Ocean Circulation Experiment (WOCE) Transindian Hydrographic Section I1 (I1). This section crosses the southern boundaries of both the Bay of Bengal (I1e) in the east and the Arabian Sea (I1w) in the west. During WOCE I1 both the Arabian Sea and Bay of Bengal acted as heat sources. The mechanisms of the heat exportation in these two basins differed slightly from each other with the deep ocean flow playing an important role in exporting heat from the Arabian Sea. The monsoonally driven southward surface flow accounted for the remaining 50% of the total heat export. Meanwhile, the Bay of Bengal was exporting heat, with half of the heat export due to surface flow and the other half due to meridional overturning at mid-depths. (Abstract shortened by UMI.)