中文摘要：

西北太平洋是生成热带气旋频率最高的海域,研究西北太平洋的热带气旋对全球和区域气候变化具有重要意义。本文使用1981~2010年30 a的热带气旋资料,采用最近邻分级空间聚类法,对西北太平洋热带气旋源地进行空间聚类,并分析了西北太平洋热带气旋的产生频数与空间分布的季节差异和年代际差异。结果表明：（1）西北太平洋热带气旋源地有三个热点区（聚集区）：南海的中北部、菲律宾群岛以东和马里亚纳群岛附近。（2）夏季和秋季是热带气旋的高发期,冬季和春季较贫乏,季节差异明显。空间分布也具有显著的季节差异,春季开始向西北偏移,秋季开始向东南偏移,冬、春季气旋仅分布在10°N以南,夏季分布范围最广,可到达北纬40°N左右。（3）西北太平洋热带气旋在厄尔尼诺年生成较少,拉尼娜年生成较多;年频数在1995年前后有显著差异,1995年之前年频数较高,1995年以后年频数明显下降;空间分布上,1995年以后,热带气旋源地的聚集区较1995年之前有向西北偏移的趋势。

英文摘要：

Tropical cyclones mostly originate the northwestern Pacific （NWP） ,which have great significance on global and regional climate changes. However, many documents mainly have focused on the changes of tropical cyclone in NWP with little spatial locations, and their methods are descriptive statistics. Thus, this paper uses the nearest neighbor hierarchical clustering method to gather the tropical cyclone genesis regions in NWP during the period of 1981 to 2010. Main results are summarized as follows. （ 1 ） Northern South China Sea, east of the Philippine islands and near the Mariana islands are three high frequent occurrence regions. （2） Cyclones mostly occur in summer and autumn, es- pecially in July to September,and their spatial distribution widely ranges from 5°N to 40°N. A few cyclones generate in spring and summer,locating at south of 10°N. （3） Tropical cyclones in E1 Nifio are fewer than in La Nifia years. Annual numbers of tropical cyclones are obviously different before and after 1995. The annual frequency in the period of 1981 ~ 1995 is higher than the period of 1996 -2010. In addition, in the later period, the locations of tropical cy- clones migrate northeasterly.