两次台风远距离暴雨过程的对比分析

利用常规高空、地面气象观测资料以及NCEP／NCAR1°×1°逐6h再分析资料，对2010年7月23—24日和2011年9月17—18日两次台风远距离暴雨进行对比分析。结果表明：两次暴雨过程虽然都受台风影响，但影响方式截然不同。前着台风直接通过低空急流将其附近的水汽、能量输送到暴雨区，降水效率高、强度大。后着台风作为扰动源，产生了类东风扰动并向西传播，在四川东部和青藏高原东部与西风带系统相遇，增大暴雨区气压梯度，诱发低空急流，增强暴雨区水汽辐合，同时延长西风带系统在暴雨区的停滞时间，造成降水时间延长。

Comparative analysis on two rainstorm processes affected by distant typhoon

Using the routine upper-air and surface weather station observations and NCEP/NCAR 6-hourly reanalysis data with resolution 1°×1°, a comparative analysis is made on the two rainstorm processes happened from July 23 to 24, 2010 and from September 17 to 18, 2011 respectively affected by distant typhoons. The results indicate that the typhoons affect the two rainstorm processes in very different ways. In the former process, water vapor and energy in and near low level jet （LLJ） are conveyed by typhoon to the rainstorm region and this process is characterized by high precipitation efficiency and great intensity. In the latter one a similar easterly disturbance triggered by typhoon as dis- turbance source propagates westerly and meets with westerlies synoptic systems over the eastern Sichnan and the eastern Tibetan Plateau en-larging pressure gradient of the rainstorm region, inducing LLJ and strengthening moisture convergence of the rainstorm region, so that the maintenance of westerlies synoptic systems arc lengthened in the rainstorm region making precipitation duration longer.