青岛地区冬季一次久旱转雨天气过程的诊断

Diagnostic Analysis of the Weather Process from Drought to Rain in Qingdao in Winter of 2010

利用气象观测资料和欧洲中期数值预报中心(ECMWF)分析场以及T639模式资料,对2011年2月26日青岛地区一次久旱转雨过程的大气环流演变及各种物理量场特征进行了分析。分析表明,印缅低槽明显加强,配合副热带高压加强北抬,使得来自南方的暖湿气流向北输送,冷暖空气在山东半岛地区交汇,是形成青岛地区自2010年10月以来久旱后区域性中雨的大尺度环流特征。而低层暖式切变和地面倒槽则是此次降雨的主要影响系统。在这次久旱转雨的天气过程中,热力和动力物理量场都表现出了明显的、有益于此次降水的特征;虽然低层水汽相对充沛,而中高层水汽输送较小,没有强烈的上升运动、丰富的暖湿能量和深厚的不稳定层结支持是此次降雨过程降雨量较小,持续时间短的主要原因。

Characteristics of the circulation evolution and physical quantity fields of the weather process from drought to rain occurred in Qingdao on 26 February in 2011 were diagnostically analyzed by using meteorological observation data, analysis fields from ECMWF and simulation data from T639. The results show that the India - Burma trough strengthened obviously and the sub - tropical high pres- sure tended to the north, the transportation of warm and moist air from the south to north, convergence of cold air and warm air over the region of Shandong, which were the main characteristics of large - scale circulation of this weather process. And the main impact sys- tems of the rainfall process are the warm shear at the low level and surface trough. During this weather process, there were relatively obvious favorable characteristics in the aspect of thermodynamic and dynamic variables. Though relative abundance moisture existed at the low level, smaller transportation of moisture at the high level, no strong vertical ascending movement and deep energy support were the main reason for small precipitation and short duration for the process.