Subsurface oscillations at an oceanic station in the Bay of Bengal

Abstract

Surface wind, atmospheric pressure and the temperature profiles in the upper layers at an oceanic station off west of Andaman Island in the Bay of Bengal have been analysed to examine the causes for the observed subsurface oscillations. For this purpose a 7 day time series data on water temperature, surface wind and atmospheric pressure have been taken. Spectral analysis of the data shows that the fluctuations of pressure and wind have varied influence on the subsurface oscillations. However, in the semi-diurnal tidal frequency band, the atmospheric pressure and normal and tengential components of wind exhibit a good coherence while at other frequencies they exhibit differential influence. The effect of the atmospheric pressure and the normal component of wind is predominant at lower frequencies and the effect of the tangential component of wind is predominant at higher frequencies. However, influence of atmospheric pressure fluctuations is less pronounced as compared with that of wind.