Property fluxes at 30°S and their implications for the Pacific‐Indian throughflow and the global heat budget

Six hydrographic basinwide sections, two in each of the three major ocean basins, are employed in a set of inverse calculations to determine the extent of exchange between the Pacific and Indian Oceans through the Indonesian Archipelago and the net global oceanic heat flux. All existing estimates of Indonesian Passage throughflow, including the largest (20 Sv), are consistent with the model constraints which combine data from the southern Pacific, Indian and Atlantic Oceans. The models and data are unable to limit the extent of the exchange, i.e., both smaller and larger throughflows produce physically reasonable circulation patterns. Seasonal and interannual variations, which have been found by other investigators and which are not resolved, suggest that in the long-term mean an estimate of about 10 Sv for the throughflow is most reasonable. Globally, at 30°S, the estimated net oceanic heat flux is −0.7 ± 0.1 PW (1 PW = 1015 W), dominated by a large (> 1 PW), southward flux in the Indian Ocean. Large equatorward heat flux values, O(0.8 PW), in the South Atlantic Basin are not consistent with the data. Therefore although the data are consistent with some water following the “warm water” return path for North Atlantic Deep Water (NADW), the “cold water” path must play the dominant role in the maintenance of the global thermohaline cell associated with the formation process of NADW.

[1]  S. Rintoul.  South Atlantic interbasin exchange , 1991 .

[2]  B. Warren.  Transindian hydrographic section at Lat. 18°S: Property distributions and circulation in the South Indian Ocean , 1981 .

[3]  C. Wunsch,et al.  Mass, Heat, Salt and Nutrient Fluxes in the South Pacific Ocean , 1983 .

[4]  J. S. Godfrey,et al.  The Sverdrup Relation in the Indian Ocean, and the Effect of Pacific-Indian Ocean Throughflow on Indian Ocean Circulation and on the East Australian Current , 1981 .

[5]  A. Bunker.  Surface Energy Fluxes of the South Atlantic Ocean , 1988 .

[6]  J. Sarmiento.  On the north and tropical Atlantic heat balance , 1986 .

[7]  G. Russell,et al.  Research paperSeasonal oceanic heat transports computed from an atmospheric model , 1985 .

[8]  A. Gordon,et al.  Pacific and Indian Ocean Upper-Layer Salinity Budget , 1984 .

[9]  L. Talley.  Meridional Heat Transport in the Pacific Ocean , 1984 .

[10]  E. Carmack,et al.  The role of sea ice and other fresh water in the Arctic circulation , 1989 .

[11]  R. Fine.  Direct evidence using tritium data for throughflow from the Pacific into the Indian Ocean , 1985, Nature.

[12]  Arnold L. Gordon,et al.  Interocean Exchange of Thermocline Water , 1986 .

[13]  Jane Hsiung,et al.  Estimates of Global Oceanic Meridional Heat Transport , 1985 .

[14]  S. Rintoul.  Mass, heat and nutrient fluxes in the Atlantic Ocean determined by inverse methods. Ph.D. Thesis , 1988 .

[15]  Bruce A. Warren,et al.  A hydrographic section across the subtropical South Indian Ocean , 1993 .

[16]  D. Roemmich.  The Balance of Geostrophic and Ekman Transports in the Tropical Atlantic Ocean , 1983 .

[17]  R. Pacanowski,et al.  The mass and heat budget in a model of the tropical Atlantic Ocean , 1986 .

[18]  L. Fu,et al.  Mass, heat and freshwater fluxes in the South Indian Ocean , 1986 .

[19]  K. Bryan.  Measurements of meridional heat transport by ocean currents , 1962 .

[20]  S. Hastenrath.  On Meridional Heat Transports in the World Ocean , 1982 .

[21]  J. Toole,et al.  Heat and fresh water budgets of the Indian ocean―revisited , 1985 .

[22]  K. Aagaard,et al.  Transports through Bering Strait: Annual and interannual variability , 1988 .

[23]  T. Harris.  Sources of the Agulhas current in the spring of 1964 , 1972 .

[24]  S. Hastenrath.  Heat Budget of Tropical Ocean and Atmosphere , 1980 .

[25]  A. Macdonald.  Mass, heat, oxygen and nutrient fluxes at 30s̊ and their implications for the Pacific-Indian through flow and the global heat budget , 1991 .

[26]  L. Fu,et al.  The General Circulation and Meridional Heat Transport of the Subtropical South Atlantic Determined by Inverse Methods , 1981 .

[27]  L. Stramma,et al.  Upper-level circulation in the South Atlantic Ocean , 1991 .

[28]  R. Wiggins,et al.  The general linear inverse problem - Implication of surface waves and free oscillations for earth structure. , 1972 .

[29]  K. Wyrtki.  Physical oceanography of the Southeast Asian waters , 1961 .

[30]  J. Minster,et al.  Redfield ratios along isopycnal surfaces—a complementary study , 1987 .

[31]  Stephen P. Murray,et al.  Throughflow into the Indian Ocean through the Lombok Strait, January 1985–January 1986 , 1988, Nature.

[32]  D. Roemmich.  The application of inverse methods to problems in ocean circulation , 1979 .

[33]  R. Sætre,et al.  The circulation of the Mozambique channel , 1984 .

[34]  C. Wunsch.  The North Atlantic general circulation west of 50°W determined by inverse methods , 1978 .

[35]  R. Newell,et al.  The annual cycle of oceanic heat storage and oceanic meridional heat transport , 1989 .

[36]  A. Bennett.  Poleward Heat Fluxes in Southern Hemisphere Oceans , 1978 .