摘要
利用常规观测资料、风云卫星资料、多普勒天气雷达资料、地面自动站资料、NECP/NCAR(1°×1°)再分析资料,对2015年6月23—26日南疆西部一次暴雨强对流过程的中尺度特征进行分析。结果表明:(1)南亚高压由带状分布向双体型调整、中亚低涡形成后发展移入南疆是此次暴雨强对流发生的天气背景。强对流发生前各种对流参数变化明显,较强的对流有效位能、强烈的垂直风切变、0℃层和-20℃层高度适宜,这些均有利于短时大冰雹和短时强降水的发生;(2)除中亚低涡自身携带水汽外,孟加拉湾、阿拉伯海和南海水汽输送为强降水区提供了充足水汽源,尤其是中低层的东南风急流辐合为短时强降水提供了水汽辐合的动力条件;(3)23日短时大冰雹和短时强降水天气由生命史达7 h、最低TBB达-36℃的中-β尺度对流云团相继造成,其中,造成短时大冰雹的中-β尺度超级单体最强回波(60 d BZ)高度达4 km、50 d BZ回波高度达-20℃层高度,而短时强降水由断裂弓形回波、飑线型弓形回波下的中-β尺度对流风暴造成;25日短时强降水由层积混合云中2个最低TBB达-44℃的中-β尺度对流云团快速移过造成。
Based on conventional observational data,TBB of FY-2G satellite,reflectivity factor and radial velocity from Doppler weather radar,automatic weather stations＇ observations and NCEP/NCAR reanalysis data with 1. 0° × 1. 0° spatial resolution,the mesoscale analysis of a heavy rainfall which occurred in the west of Southern Xinjiang from 23 to 26 on June 2015 was studied. The results are as follows：（ 1） South Asia high converted zonal distribution into the double body type,and Central Asian vortex developed and moved to Southern Xinjiang,these were weather background of torrential rain. The convective parameters changed obviously before strong convection occurring. The strong convective available potential energy,strong vertical wind shear,favorable height of 0 ℃ and-20 ℃ level were conducive to short-time heavy rainfall and short-time heavy hail occurring.（ 2） Central Asian vortex,Bay of Bengal,Arabian Sea and the South China Sea provided sufficient moisture for severe convective weather. Especially,convergence of the southeast wind jet on middle-low level provided a good dynamic condition for water vapor convergence.（ 3） Meso-β scale convective clusters caused short-time heavy hail and heavy rainfall on 23 June 2015,which had 7 hours life history and the lowest TBB of-36 ℃. And meso-β scale supercell with low-level convergence,storm top divergence caused short-time heavy hail,which had strongest echo of 60 d BZ（ being up to 4 km）,50 d BZ echo reached the height of-20 ℃ level. While meso-β scale storm caused the short-time heavy rainfall,which was parts of broken bow echo and squall line bow echo. The short-time heavy rainfall on25 June 2015 was caused by two meso-β scale convective clusters,which had the lowest TBB of-44 ℃.
出处
《干旱气象》
2017年第3期475-484,共10页
Journal of Arid Meteorology
基金
科技部公益性行业科研专项(GYHY201506009)
国家自然科学基金项目(41565003)
新疆气象局青年基金项目(Q201604)共同资助
关键词
短时强降水
冰雹
水汽输送
超级单体风暴
飑线型弓形回波
short-time heavy rainfall
hail
vapor transportation
supercell storm
squall line bow echo
