高空形势与山东半岛冷流暴雪的关系

Relationship of High-altitude Situation and the Cold-air Blizzard on the Shandong Peninsula

采用常规观测资料和NCEP 1°×1°资料,对山东半岛2005年、2008年、2010年的几次典型冷流暴雪过程进行了分析。分析结果表明:冷流暴雪的高空形势主要分为高空冷涡型和高空横槽型。高空冷涡型较高空横槽型降雪量偏大,暴雪站点多。高空冷涡型500 hPa层以上的位涡值较高空横槽型偏大,高层位涡有利于低层正涡度的加强,促使低层产生低压环流及辐合上升运动,上升运动加强了海面水汽的垂直输送,故高空冷涡型上升速度较高空横槽型强,湿层较厚,高空冷涡型较高空横槽型更容易产生暴雪过程。

Several typical cold-air blizzard processes on the Shandong Peninsula in 2005, 2008, 2010 have been analyzed by conventional observational data and NCEP 1°× 1° data. The results show that： the high-altitude situation .of cold-air blizzard is divided into cold eddy and cross-slot. The snowfall and blizzard points of high-altitude cold eddy are more than those of cross-slot. PV of cold eddy above 500 hPa layer is greater than that of cross-slot. Top vorticity is conducive to strengthen positive vorticity on low-level, and produces low voltage circulation on low level, which can produce the convergence rising motion strengthening the sea water vapor vertical transfer. Therefore, rising velocity of cold eddy is stronger than that of cross-slot, humidity layer is thicker, and cold eddy is easier to produce the blizzard , process.