Water masses in the northern South China Sea

Using the fuzzy clustering as the principal method, eight water masses in the northern South China Sea (NSCS) are distinguished.They are Alongshore Diluted Water Mass (F), Nearshore Mixed Water Mass (M), Warm Surface Water Mass (WS), Surface Water Mass (S), Surface-Subsurface Mixed Water Mass (SU), Subsurface Water Mass (U), Subsurface-Intermediate Water Mass (UI) and Intermediate Water Mass (1).A synthertic study is made on the formations, basic properties and modified characters of each water mass and the regularities of their disributions and growth and decline variations.They may be classified into three types:the type of runoff-diluted water (F).the type of shallow sea-modified water (M, WS.S.and SU) and the type of deep sea-oceanic water (U, UI, and I).