Physical property distributions and seasonal trends in Spencer Gulf, South Australia: an inverse estuary

Abstract

Results are described from the first long-term, systematic program of oceanographic measurements in Spencer Gulf, South Australia. The gulf belongs to a subset of semi-enclosed seas that are characterized by a net fluid loss, in this case induced by excess evaporation, and a resulting circulation that is the reverse of that found in a classical estuary. In Spencer Gulf, this inverse estuary character involves the production of salinities as high as 48 at the head in late summer. The seasonal variations of temperature and salinity, from both large-scale CTD surveys and time-series observations at a fixed station, reveal the manner in which the gulf responds to seasonal influences. From such information, the gulf's dispersive capabilities are quantitatively assessed, and the implications of thermohaline processes for gulf-ocean exchange are discussed.