Observed Current Variability on the North Western Bay of Bengal using HF Radar Derived Ocean Currents

A pair of HF Radar (Courtesy: INCOIS, Hyderabad) has been operating in the North Western Bay of Bengal (BoB) along the Odisha Coast from late 2009 to enable us to study the current variability in this region for the very first time. Due to the absence of the observed in-situ current observations, the HF radar derived surface currents are validated with geostrophic (AVISO) and the wind driven (ASCAT) currents on the daily scale. The higher correlation in the current magnitude and direction gave the confidence to study the high frequency variability. The tidal analysis of the HF Radar datasets indicates that the semi-diurnal tidal component (M2) dominates in the North-Western BoB along with S2 and N2 components. This result agrees with the past studies from the tide observations and model. In addition, the well-known diurnal tidal components K1, O1 and Q1 have also been observed, pointing out that the tidal regime is of mixed type and mainly semi-diurnal. Keywords: Bay of Bengal, HF Radar, Ocean currents, Ocean Circulation, Tides