THE RELATIONSHIPS BETWEEN TROPICAL CYCLONE TRACKS AND LOCAL SST OVER THE WESTERN NORTH PACIFIC

Tropical Cyclone (TC) tracks over the western North Pacific (WNP) during 1949-2007, obtained from China Meteorological Administration/Shanghai Typhoon institute, are classified into three track types. These types are the main pathways by which TCs influence the coast of East Asia. The relationships between local sea surface temperature (SST) in WNP and TC tracks are revealed. Results show that the local SST plays an important role in TC tracks, though the relationships between local SST and the frequencies of different TC tracks are very dissimilar. The local SST has significant positive correlation with northwest-path TCs, and negative correlation with recurving-path TCs. However, the west-path TCs do not have statistically significant relationship with the local SST. The upper sea temperature anomalies which influence TC tracks last about six months before TC occurrence. Further analysis indicates that the ocean conditions influence TC tracks by modifying the atmospheric circulation, and then the modified atmospheric circulation can affect TC's genesis location and motion.