Study On Relationship Between The Subtropical High And Tropical Cyclones Which Have Influenced The South China Sea

The South China Sea(SCS) is situated in the tropical convergence zone, it is the most active sea areas in the world. There are two kinds of tropical cyclone which can affect the SCS, one is originate from the SCS, another move into the SCS after generate from the Northwestern Pacific. Those two kinds of tropical cyclone can do unavoidable big impaction to the SCS, especially when they make landfull, all they bring to the coasts people are immensurable life loss and property loss. To decrease the loss, forecasters must make an accurate tropical cyclone forecast as soon as possible, and convey to the users as soon as possible. So research on the tropical cyclones which have influenced the South China Sea is very important to the marine disaster prevention and reduction.In the Chapter 3, The authors counted and analyzed tropical cyclones which have influenced the South China Sea in the year 1976-2005, those characters including decadal,inter-annual,inter-monthly change,cradle,intensity and moving track were studied separately. In the last part, storm surge events in the past ten years are summarized.In the Chapter 4, characters of the subtropical high are counted and analyzed, which include decadal,inter-annual,inter-monthly change, further more, it's effection on the track of tropical cyclone are also studied.The results showed that after El Nino occurred, the tropical cyclones originating from the northwest Pacific tended to be fewer and more intense, and the originating positions were partial to the east. The intensity of the subtropical high and the SST in Ni(n|~)o 3.4 have the same trends in the main, only the change of the subtropical high fall behind the SST change for about six months. Since El Ni(n|~)o usually occurred in the first half year, while the SST in Nino 3.4 was on the high side, so the subtropical high in the same winter or the next spring and summer was always stronger. The next year after El Ni(n|~)o occurred, warm water returned back to the west Pacific, the SST of the west Pacific gradually returned to normal, and the subtropical high got intense.