Abstract:

The long-term tendency of tropical cyclone (TC) position were examined when they reach the different intensities including life-time extreme, tropical storm and typhoon in this study. The data were obtained from JTWC, CMA and JMA from May to November of 1980-2013. The results indicated that TCs over the western North Pacific presented the poleward tendency at most of intensity levels, and the tendency was statistically significant in all three datasets and reached up to 90, 93 and 113 km per decade, respectively. Besides, the positions, when TCs achieved the level of typhoon and tropical storm, had relatively apparent poleward and westward tendency. By analyzing the variation characteristics of factors including vertical wind shear, sea surface temperature, and genesis potential index, further study was conducted to give a possible physical explanation for the long-term tendency.

Key words: tropical cyclone, western North Pacific, different intensity, variation tendency