以一次飑线过程为例对多普勒天气雷达资料适用性分析

Illustrative Analysis on Doppler Radar Data Applicability with A Squall Line Process

利用常规资料和多普勒资料,对2008年9月7日的一次较长生命史飑线过程进行综合分析,对多普勒雷达几个产品的适用性进行初步探讨。结果表明,在雷暴单体发展各个阶段,从雷达观测数据上可以分析出系统流场以及环境风场,两者相互影响会在雷达回波上显示特殊的配置形势。这种在大面积正速(负速)区里嵌套一小块数值均匀的负速(正速)区的配置经常被误判为中气旋,实际上这是由于在对流系统中层发生的径向辐合而产生的。在适当仰角的速度图(V26)上迭加风暴追踪信息(58STI),便于分析出风暴的发展阶段。通过对风暴追踪信息产品在单体发展的各个阶段上的预报准确性探讨,以及一些其他产品的适用性研究,并将结论利用于短时预报和诊断分析上,以期提高目前短时预报的水平。

Overall analysis is conducted based on conventional data and Doppler data for a squall line process with longer life history on September 7,2008 for the purpose of a preliminary discussion about the applicability of several Doppler products. The analysis confirms that during each development stage of the thunderstorm cells,system fluid field and environmental wind field,whose interaction will reveal a special distribution on？radar echoes,can be observed from the radar data. Such a distribution as a small patch of negative （positive） speed zone with homogeneous values nested in a large area of positive （negative） speed zone is frequently misjudged as meso-cyclones,however it is mid altitude radial convergence,MARC from mid altitude of convective system in fact. A velocity diagram（V26）of favorable elevation angle with the superposition of tracking information （58 STI）will facilitate the analysis of storm development stages. Discussion on the forecast accuracy at each cell development stage for storm tracking information product,along with the applicability study of other products are expected to improve the current short-term forecast when those conclusions are to be used in short-term forecast and diagnosis.