4. Ocean Current Characteristics

As a basic motion of all the world’s oceans, ocean currents play an important role in the development of marine fisheries, surface primary productivity, material transportation, humanitarian assistance such as the placement and arrangement of mines, buoy movement, determining the location of underwater equipment, and so on. Intensive study of the surface winds, waves, currents, and other marine environmental factors can provide a scientific basis for sociological marine construction activities and humanitarian assistance. Cold and warm currents have an influence on the coastal climate, as during the Younger Dryas event about 11–10 Ka BP. In addition, areas where cold and warm currents intersect are the world’s most famous fishing grounds, as these areas are rich in nutrients. In the polar seas, currents also influence navigation by affecting the motion of sea ice. Recently, the Indo-Pacific region (IPR), the Indonesian Through Flow (ITF), and the Agulhas current have become hot spots for studying climate change. There are few research papers on Indian Ocean currents, and the scattered papers that do exist are focused on hot spots such as the ITF or on the effects of the IPR on the climate of China. On the basis of the reanalysis of current data, this chapter briefly introduces the characteristics and seasonal variations of currents in the Indian Ocean and the South China Sea (~20°S–30°N, ~30°E–130°E) to make a contribution to national marine construction and strategic planning.