影响山东的黄淮气旋暴雨落区分析

应用常规观测资料、NCEP再分析资料,对比分析了山东两次春季黄淮气旋暴雨落区异同点。发现春季影响山东的黄淮气旋暴雨区集中出现在气旋中心北侧的偏东风中,且主要位于东北气流中。暴雨区偏北的程度,与影响系统的后倾程度及我国东北地区是否存在高压有关。当系统明显后倾时,锋面坡度小,暖湿气流沿锋面向北爬升的更远,暴雨区更偏北;当我国东北地区存在高压时,其南侧东北气流经渤海侵入850 hPa低涡后部,与低涡前东南气流在风向上渐近辐合,在低涡北侧产生辐合中心,从而产生暴雨区。此外,地面东北风形成的冷垫,有利于南方暖湿气流向北爬升。实际暴雨落区预报中,需综合分析系统的空间结构、周围系统的影响及温度场的配置等。

Analysis on the Areas of Torrential Rains Affected by Huang Huai Cyclone in Shandong Peninsula

Using the conventional observation data, NCEP reanalysis data, two cases of spring torrential rains in Shandong Peninsula are studied. The results show that the rainfall caused by spring Huang Huai cyclone in Shandong Peninsula is concentrated in the northern part of the cyclone and mainly located in the northeast air stream. The northerly extent of rainfall areas are related with synoptic backward extent and the existence of the high pressure in Northeast China. When the synoptic system is obviously backward and the frontal slope is small, warm air stream along the front climbs north further and the rainfall moves northerly. If there is a high pressure in Northeast China, northeasterly wind at the southern side of the high invades the vortex at 850 hPa joined by the southeasterly wind. The asymptotic convergence in the northern part of the vortex generates the rainfall. Furthermore, the formation of cold northeasterly air stream is favorable for the climbing of warm air northward. In operation, it is necessary to analyze the spatial structure of the system and the impact of the surrounding temperature field comprehensively.