The surface salinities range from 34 (March through May) to 34.6 (September through November) and the temperatures from 25.7 C in August to 28.6 in May. The surface currents are variable with the seasonal monsoon winds. The deep water in the Halmahera Basin is renewed by water from the Pacific which passes from north to south over sills 700 m and 940 m deep. The surface waters are a mixture of oxygen rich Pacific water and oxygen poor water from the Seram Sea. See Fairbridge (1966).
Helium-3 is used in combination with tritium to date water on timescales of 0-10 years with a resolution of around 0.1 years (in North Atlantic surface waters). It is better to treat them as separate but related tracers on longer timescales or in the presence of extensive mixing. Their relationship is a diagnostic of vertical versus horizontal mixing, and has been used to assess an upper limit to vertical mixing that is consistent with physical estimates. This has also been used to show that horizontal mixing is the dominant mechanism of thermocline ventilation in subtropical gyres. See Sarmiento (1988) and Broecker and Peng (1982).