Mass, heat, salt, and oxygen budgets in the Tasman Sea, May‐June 1993

In May and June 1993, as part of New Zealand's contribution to the World Ocean Circulation Experiment (WOCE), three hydro‐graphic sections were made to enclose the Tasman Sea. Two of these sections followed WOCE repeat hydrography lines: PR13N, between New Zealand and Tasmania along 43° 15‧S, and PR11 from north of New Zealand to Australia along 30°05′S. The third section was made along 173°E from north of New Zealand to close the box, thus enabling mass, heat, salt and oxygen balances for the Tasman Sea to be estimated. The geostrophic transport along 30°05′S was 11.9 Sv into the Tasman Sea, the transports out through 43°15′S and 173°W were 6.6 and 6.7 Sv, respectively, leading to a net outflow of approximately 1.4 Sv. To some extent this is balanced by a total Ekman transport into the Tasman Sea of 0.6 Sv, leaving a total volume deficit of 0.8 Sv. Integrating the heat fluxes into the Tasman Sea indicates a net heat inflow of 1.2 × 10 14 W into the sea during the cruise. Balancing this by heat flow into the atmosphere, would require an average heat flux of about 48 W m −2 . The salt budget is approximately balanced with 4.3 × 10 8 kg s −1 entering through the northern section, which is approximately evenly split through the southern and eastern boundaries. A net oxygen outflow of 500 mol s −1 from the Tasman Sea indicates either a net inflow through the surface, or a net increase through biological production.