83rd Annual

Monday, 10 February 2003
Decadal changes in summertime typhoon track
Joo-Hong Kim, Seoul National University, Seoul, Korea; and C. H. Ho, J. J. Baik, D. Y. Gong, and C. H. Sui
Poster PDF (338.0 kB)
The present work examines decadal variations of typhoon track in the western North Pacific (WNP) during boreal summer (June through September) for the period 1951-2001. Typhoon track is expressed in percentage value of the total number of typhoon passage into 5ư5 longitude-latitude grid box to the total number of typhoon formation. As the analysis period is divided into the earlier (1951-1979) and later (1980-2001) periods, typhoon passage frequency has decreased enormously in the east coast of South China and Philippine Sea and has increased a little in South China Sea in the later period. In addition, the time series of typhoon passage frequency over the east coast of South China and South China Sea represent a regime shift in the late 1970s. Those over Philippine Sea, however, indicate a continuous downward trend with a -9% per decade. The decadal changes in typhoon track are investigated in conjunction with the westward expansion of the subtropical northwestern Pacific high (SNPH) in the late 1970s. The expansion of SNPH to the southeast coast of Asia may result in a larger elliptic pathway of typhoon migration. Corresponding effects on typhoon track would be the same as in the difference between the earlier and later periods. The major typhoon formation regions also show westward shift in the later period. This may partially influence the decadal changes in typhoon track.

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