午夜欧美大片免费观看,欧美激情综合五月色丁香,亚洲日本在线视频观看,午夜精品福利在线

The track data of tropical cyclones (TC) provided by the Chinese Meteorological Administrator from 1949 to 2009 are employed to analyze the climatic characteristics of TC activities over the Northwest Pacific，including the temporalspatial variations of TC sources, the interannual and intermonthly variation of the TCs formed and landed on China, the distribution of TCs intensity and tracks, etc. The results show that the number of TCs formed on China has been decreased for more than 60 years, although there was little change in the number of landfall TCs, but the highintensity TCs increased in recent 10 years, with the peak period being from June to October, especially in August; the greater the intensity was, the later the TC occurred; the average life period of TCs increased with increasing TC intensity, with a singlepeak pattern; as for the geographical distribution of TC occurrence frequency, TCs were mainly concentrated around the South China Sea and the ocean area east of Philippines, decreasing radially outward; however, the TCs tended to stretch westward with the intensity slightly increasing in recent 10 years.