排序方式: 共有55条查询结果,搜索用时 0 毫秒
51.
52.
广东前汛期西风槽暴雨个例的强度及落区 总被引:8,自引:25,他引:8
利用实况观测资料和NCEP的1°×1°格点资料,分析了2005年5月7~10日广东暴雨过程。结果显示:这次暴雨过程主要是由500 hPa西风波动中先后两个小槽东移逼近,配合850 hPa西南风加强造成的。降水中心主要落在槽前正涡度区右侧、涡度梯度最大的区域;暴雨落区与西南风急流位置的对应关系和造成西南风加强的系统有关;在影响系统起作用的背景下,降水落区与垂直风速切变的最大中心重合,与垂直风向的顺时针切变密切相关;天气系统相联系的低层负螺旋度越深厚,降水量越大,雨势越强。 相似文献
53.
粤东台风“浣熊”大暴雨的辐散风动能分析 总被引:1,自引:0,他引:1
利用热带气旋和雨量观测资料、NCEP再分析资料和辐散风动能方程,对台风"浣熊"在粤东造成大暴雨到特大暴雨的大尺度环流及动能转换特征进行了分析。结果表明,此次强降水过程主要是台风残涡与周围环境相互作用的结果。来自西太平洋的低层强偏东南急流和与热带气旋相连的西南急流,维持强水汽输送且输送至粤东地区;辐散风动能的变化对本次过程有较好的指示意义;低空两支急流的分布及辐合变化造成的动能通量辐合效应,是暴雨区辐散风动能的主要能量来源。此外,两支急流中心分别存在暖空气上升和冷空气下沉运动,斜压有效位能释放转化为辐散风动能。在上述两种过程中,冷空气均起到了重要作用。在低层近似辐合条件下,大气层结条件的不同是造成粤东和登陆点附近降水强度差异的重要原因。 相似文献
54.
Warm-sector torrential rainfall (WSTR) events that occur in the annually first rainy season in south China are characterized by high rainfall intensity and low radar echo centroids. To understand the synoptic characteristics related to these features, 16 WSTR events that occurred in 2013-2017 were examined with another 16 squall line (SL) events occurred during the same period as references. Composite analysis derived from ERA-Interim reanalysis data indicated the importance of the deep layer of warm and moist air for WSTR events. The most significant difference between WSTR and SL events lies in their low-level convergence and lifting; for WSTR
events, the low-level convergence and lifting is much shallower with comparable or stronger intensity. The trumpet-shaped topography to the north of the WSTR centers is favorable for the development of such shallow convergences in WSTR events. Results in this study will provide references for future studies to improve the predictability of WSTR. 相似文献
55.