抄録
It is very important to investigate the global hydrological circulation and water budget in order to understand how the global changes affect the change of local water resources. The vapor flux convergence-∇H·Q over the globe was estimated from the objective analysis data of ECMWF global analysis data for the period 1985 to 1988. Around 70 large river basins were distinguished, and they cover nearly 55% area of continents and they share around 75% of global annual river runoff estimated by atmospheric water balance from-∇H·Q. Remaining meshes were also attached the location of river mouth at the nearest coast. The annual transport of freshwater to the ocean from both atmosphere and rivers were estimated by the geographical information of the river mouth and the basin boundary. The results showed good correspondences qualitatively with former estimates of the annual water balance (precipitation minus evaporation) in the ocean, and the amounts of freshwater supply from rivers were comparable to the amounts from the atmosphere. Annual water transport in latitudinal direction was also estimated. Transportation by the atmosphere and by the ocean have almost same absolute value in each latitude with different sign, and the water transport by rivers is around 10 % of them globally.
