Circulation in the Gulf of Carpentaria. II. Residual currents and mean sea level

Abstract

Recent observations of satellite-tracked drogued buoys in the Gulf of Carpentaria indicate a slow, clockwise mean circulation, which appears to be a permanent feature in the Gulf. Residual currents, derived from 3-5 months of recent current-meter observations, and from a numerical tidal model of the Gulf, are compared with the motions deduced from the buoys. North-west monsoon winds and density-induced currents enhance the clockwise circulation. However, application of the south-east trade-wind stress at neap tides drives a counterclockwise circulation, and at spring tides, a weak clockwise circulation. The large annual variation of mean sea level in the Gulf is a maximum in the south-east corner (75 cm): 70% of this can be accounted for by the effects of winds, atmospheric pressure, and steric variations, all of which exhibit marked seasonality, are approximately in phase, and are thus additive.