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(9) PIOLA and GORDON (1984) estimate that the Agulhas and Leuwin currents togethertransport about 19 sverdrups (1 sv = lo6 m3/s) southward in the upper layers of the IndianOcean. The maximum estimate of the inflow into the Indian Ocean through the Indonesianpassages is 14 sv. The balance must be supplied, therefore, by upwelling fed by deep-watercurrents from the Southern Ocean.(10) The subdivision of the basin by meridional ridges results in three separate deep circulationgyres with separate deep western boundary currents (See Fig. 4).RESEARCH PROBLEMSSome of the features listed above are not well understood quantitatively. They all involvesecondary processes and phenomena that can affect economic relations. Among them are regional andglobal changes of the climate, the dispersion of pollutants, fluctuations in biological activity andvariations in the location, and the rate of sedimentation. Most of these processes require furtherresearch for their elucidation, and some of this research depends on large-scale internationalcooperation.The oceanographic problems and research topics of concern can be listed conveniently undertwo geographical headings:A The Monsoon-driven regime of the northern Indian OceanB - The Subtropical gyre and the Subantarctic regionThe following problems in area A have attracted a good deal of scientific attention:Al: It is not fully known to what extent the dynamics of the reversing Somali Current andthe cross-equatorial western boundary flow are affected by local wind stress changes and towhat extent they are determined by teleconnections with the central Indian Ocean. Thephenomenon may affect the time of onset and cessation of the Indian Monsoon.A2: The pattern and dynamics of the southward heat transport across the equator in theIndian Ocean is not well know. Quantitative information and a better understanding is neededfor a better assessment of the planetary heat balance and for an improved understanding of theglobal climate.A3: The onset of the Monsoon can produce very rapid changes in the wind stress patternover the Arabian Sea as indicated by Fig. 5. During summer, the region is exposed to verylarge gradients of the wind stress curl (Fig. 6), juxtaposing upwelling along the Arabian andIranian coast with strong downwelling a relatively short distance further south. This type ofwind forcing must affect the oceanic circulation and turbulence. Its influence uponproductivity, surface temperature and ultimately variations in the Indian Monsoon has not beenfully investigated so far.A4: Surface currents tend to reverse also in the region south of IndidSri Lanka. It appearsthat these currents carry about three times more water eastward in summer than westward inwinter. It is not known where and when the resulting net inflow of water into the Bay ofBengal is compensated.A5: The semi-annual variation of the equatorial current system has been the subject ofinvestigations by McPHADDEN (1982), GENT et al. (1983) and REVERDIN and CANE(1984), but the subject deserves further observational and theoretical study.A6: Systematic observations of the water transport through the Indonesian passages arenow being planned under a joint U.S./Indonesian program. However, the projected durationof this program may be too short to resolve the dependence of this transport upon interannualsea-level changes in the Pacific. (Southern OscillationEl Niiio).A7: Precursors of the Southern OscillationEl Niiio phenomenon in the Indian Ocean havebeen stipulated or derived from statistical evidence by several investigators. If the existence ofthese precursors could be confmed, this could have considerable predictive value.The southern area of the Indian Ocean has not been explored intensively. Among the openresearch problems there one might list the following topics:B1: What is the fate of the water transported by the Agulhas Current and what is the natureof the Atlanticbndian Ocean water exchange? (See e.g., DE RUIJTER, 1982; OU and DERUIJTER, 1986.)44