Variation Tendency of TC Activity in the NWP

Based on the tropical cyclone dataset during 1945∼2013 by Joint Typhoon Warning Center (JTWC), this study has systematically analyzed the long-term variation of tropical cyclone (TC) in the Northwest Pacific (NWP). People recorded annual variations of Typhoon's maximal wind speed, power dissipation index (PDI) and frequency in this period. The results showed that these meteorology parameters display a rising trend, implying that the TC activity presents a feature of non-stationary stochastic processes. Geographically, we give spatial distribution of their historical maximal wind speed by combining database with parametric TC model. The results indicate that spatial distribution of TC intensity in the NWP is uneven and the sea area east to the Philippines is the most severely affected region by typhoon.