【摘要】 利用多普勒天气雷达资料、常规观测资料及NCEP/NCAR再分析资料,对2007年8月10—12日发生在山东半岛持续性特大暴雨的特征及维持机制进行了分析。结果表明:本次持续性特大暴雨与西太平洋副热带高压中心稳定少动和其边缘不断有冷空气侵入有关;雷达回波强度图上,10—11日最强回波>50dBz,12日回波强度在40～45dBz,其径向速度的零速度线表现不同,但均反映为暖平流;暴雨前期山东半岛具备了发生强雷暴所需的不稳定大气层结,副高边缘的低空东南急流为山东半岛输送了充足的水汽,从而有利于山东半岛暴雨的维持;暴雨维持的动力场特征为:散度场维持低层辐合、高层辐散,垂直速度场为较强的上升运动。更多还原

【Abstract】 An analysis of the characteristics and maintaining mechanisms of a persistent heavy rain event that occurred in Shandong Peninsula from 10 to 12 August 2007 was undertaken using Doppler radar data, conventional observations and NCEP / NCAR reanalysis data. The results show that the persistent heavy rain was related to a stable subtropical anticyclone and the intrusion of cold air on the west side of the subtropical anticyclone. The Doppler radar data show that the reflectivity of the heavy rainfall was more than 50 dBz on the 10th and 11th, and from 40 to 45 dBz on the 12th. In the velocity field, the wind vectors reveal the presence of warm advection. The heavy rainfall event was closely related with unstable conditions. Sufficient amount of water vapor over the Shandong Peninsula was transferred by a low-level southeasterly jet along the west side of the subtropical anticyclone, which was advantageous to the maintenance of the heavy rain in Shandong Peninsula. The heavy rainfall that caused floods was characterized dynamically by the observed convergence in lower troposphere and divergence in upper troposphere. The ascending branch of the vertical motion maintained with the heavy rainfall.更多还原