利用台风最佳路径资料以及NCEP全球再分析资料,采用客观判定标准对1951—2014年西北太平洋2类双台风活动进行识别及气候特征分析,并对典型类双台风活动极值特征给出合适的解释。当2个台风之间距离d≤1 800 km时被定义为双台风活动;双台风活动又划分为典型类双台风和非典型类双台风。双台风活动的主要气候特征如下:1951—2014年西北太平洋一共出现699对双台风活动,其中典型类双台风和非典型类双台风分别为446对和253对,分别占到63.8%和36.2%;典型类双台风对比例随过程最短距离减小而增大,非典型类双台风对比例随过程最短距离减小而减小。典型类双台风过程相互靠近速度最大时刻,双台风对主要表现为东—西向分布,正好受副高南侧东风气流控制,有利于东台风快速靠近西台风;典型类双台风过程逆时针互旋角速度最大时刻,双台风对主要呈东北—西南或东北东—西南西向分布,并位于副高西侧和西南方主要受东南风为主控制,有利于双台风的逆时针互旋。

Based on typhoon best track data of China Meteorological Administration and NCEP global reanalysis data, this study analyzed the characteristics of binary tropical cyclones (TC) in the Northwest Pacific Ocean during 1951 to 2014 by using the objective determine standard. When the distance between the two TCs d≤ 1 800 km, they are defined as binary tropical cyclones or binary typhoons. And binary typhoons are divided into two different types which are typical binary typhoons and atypical binary typhoons. The climatic characteristics of binary tropical cyclones are as follows: There were 699 pairs of binary typhoons in Northwest Pacific Ocean during 1951 to 2014. In these cases, there were 446 pairs of typical binary typhoons and 253 pairs of atypical cases, occupying 63.8% and 36.2%, respectively. The proportion of typical cases increased with the shortest distance decreasing, while the proportion of atypical cases decreased with the shortest distance decreasing. When the speed of typical binary typhoons moving towards each other reached the peak, binary typhoons mainly showed the east to west direction. At this time, typhoons were controlled by easterly stream of the southern edge of the subtropical high. In this situation, the east typhoon moved toward the west typhoon quickly. When the anticlockwise angular velocity of typical binary typhoons reached the peak, binary cases distributed northeast to southwest or east-northeast to west-southwest, appearing in west and southwest edge of the subtropical high and mainly being controlled by southeasterly stream, thus benefiting the anticlockwise rotation between the typical binary typhoons.