IMPLICATIONS OF THE SALT AND HEAT BUDGETS OF THE GULF OF THAILAND

Hydrographic data collected during 1959 and 1960 in the Gulf of Thaila nd, combined with supporting climatological data, have been used to in vestigate the salt and heat budgets of the Gulf. A simple model includ ing mixing, net precipitation, local river run-off and Ekman flux pred icts the flushing time of the Gulf, associated with processes other th an the Ekman flux, to be 12.0 months, but predicts too small a magnitu de and the wrong phase for the observed seasonal salinity cycle. Addin g the discharge from the Mekong River reduces the flushing time to 5.4 months and improves the fit to the magnitude of the observed salinity cycle. The phase matches if a 2-month delay in the time for the Mekon g discharge to reach the Gulf is allowed. The Mekong River appears to be a vital source of fresh water to the Gulf. Using the flushing time required to balance the salt budget and a model for temperature which incorporates the climatological net heat flux values, the Gulf is pred icted to be warmer than observed. The annual cycle of net heat flux re quired to match the observed temperature cycle has a mean and an ampli tude both of which are smaller than the published climatological value s, but only by about 10 W/m(2) (annual net heat flux). Our simple mode l, using half the Mekong discharge, suggests that a uniformly distribu ted tracer would be flushed (90% removal) from the Gulf in 7 to 9 mont hs, with the Ekman and non-Ekman exchange processes of approximately e qual importance.