Monsoon Variability and the Diurnal Cycles of Temperature and Salinity in the Bay of Bengal
[26-Feb-2014] Riser, S.C. and Anderson, J.
Presented at the 2014 Ocean Sciences Meeting
We present observations from a suite of profiling floats in the Bay of Bengal equipped with enhanced temperature and salinity sensors capable of measuring water properties very near the sea surface. The floats were programmed to cycle between the surface and 150 meters at 2 hour intervals, resulting in records several months long before the batteries were exhausted. We have observations from both the northern and southern regions of the Bay of Bengal, during both the summer and winter monsoons. The data clearly show diurnal cycles of both temperature and salinity superimposed on eddy-like motions and the seasonal cycle. In the northern Bay of Bengal the seasonal cycle is dominated by changes in freshwater, with daily variability in rainfall resulting in a discernible diurnal cycle in temperature and a weak, broadband diurnal cycle in salinity that is stronger in summer than in winter. In the southern part of the Bay the diurnal cycles are stronger than in the north in both summer and winter. These diurnal cycles are likely important for heating and freshening the Bay of Bengal on longer time scales, and the results from this work are likely to be of use in improved models of air-sea interaction and the monsoon cycles in this region.