中国近海温带气旋的时空变化特征

基于1979-2012年共34年的ECMWF逐日4次平均海平面气压的再分析资料,采用英国雷丁大学气旋客观追踪算法,对出现在我国近海的温带气旋(气旋生命史1d以上,移动距离大于500km)的时空分布特征进行统计分析。结论包括以下几点:(1)1979-2012年进入中国近海的温带气旋平均每年45个,气旋数量呈现春夏多而秋冬少的特点。20世纪90年代初至今,气旋数量呈增加趋势,其中北部海区气旋数量增加达到显著水平,东部海区气旋数量表现为不显著减少,故认为影响中国近海的气旋路径有北移的趋势。(2)进入我国近海的温带气旋主要有4个生成源地,按比例由高到低分别是江淮气旋(38.9%),东海气旋(25.2%),黄河气旋(24.3%)以及蒙古气旋(11.6%)。气旋入海后,当大气海洋条件适合时,可以爆发性增长,气旋爆发性增长的主要区域在朝鲜半岛及以东洋面以及日本以东洋面,在我国近海气旋爆发的比例较小。(3)气旋生命史主要为1~7d,但生命史为1~4d的气旋比例最大,平均占气旋总数的52%,其中夏季长生命史气旋(大于10d)的比例最大,为8%,冬季最少,接近3%。冬季气旋最强,气压分布区间大;夏季弱气旋多,中心气压分布集中。

The statistic and variance of cyclones entering coastal waters of China in 1979-2012

Based on the 6 hourly sea level pressure data of ERA-Interim reanalysis over the period 1979-2012 and automated cyclone detection and tracking algorithm from Reading University,extratropical cyclones entering coastal waters of China are examined and their activities such as source,distribution,intensity,frequency,life time,annual and seasonal variability and so on are investigated. Conclusions are as follows:(1)From 1979 to 2012,there are 1 530 extratropical cyclones are detected in coastal waters of China,45 per year on average. Since the early 1990s the number of extratropical cyclone in coastal waters of China shows positive trend,and the route has a tendency to move northward. This is consistent with previous research conclusion of extratropical cyclone in the northern hemisphere. Especially in the north of coastal waters of China ,cyclone number increased significantly. (2)These cyclones mainly come from four regions,Jianghuai,Yellow River,East China Sea and Mongolia,and the most proportion is Jianghuai,the least is Mongolia,especially in summer. When atmospheric and ocean conditions meet the requirements,the cyclones can growth explosively.The main sources of explosive cyclones are east ocean of Japan and the east ocean of of Korean Peninsula,compare to this tow place,there are less cyclones can growth explosively in coastal waters of China .The number of explosive cyclones is the largest in spring,the least in summer. More than half of the cyclone's life is for 1 to 4 days,the number of long life cyclones(more than 10 days) is the largest in summer,the least in winter. The cyclones are more stronger in winter and more weaker in summer.