湘北特大致洪暴雨的中尺度分析及数值模拟  

MESOSCALE SYSTEM AND NUMERICAL SIMULATION ANALYSIS OF HEAVY RAIN IN THE NORTH OF HUNAN PROVINCE

作　　者：周慧 陈江民 刘电英 李巧媛 陈德辉[3] 

机构地区：[1]湖南省气象台,湖南长沙410007 [2]益阳市气象台,湖南益阳413000 [3]中国气象局国家气象中心,北京10008

出　　处：《热带气象学报》2014年第4期777-785,共9页Journal of Tropical Meteorology

基　　金：气象关键技术集成与应用(CMAGJ2014M36;GYHY20120616;CMAGJ2013M33;CMAGJ2011Z07)共同资助

摘　　要：利用地面加密观测资料、卫星云图和长沙多普勒天气雷达资料,结合GRAPES_Meso中尺度数值模式模拟结果,对2010年7月8—9日湘北特大致洪暴雨过程进行综合分析。此次大暴雨过程形成的环境条件是低层切变线维持并诱发出地面风场辐合线,产生强烈的垂直上升运动,配合丰沛的水汽输送和高不稳定能量释放。造成局地强降水成因有:(1)两个β中尺度强对流云团发展合并加强且停滞少动;(2)在暴雨旺盛阶段,岳阳临湘强降水区的假相当位温θse线呈"?"型结构,低层的假相当位温348线呈暖舌,向上伸展到630hPa左右,而高层θse为向下凹的"漏斗"形状,这种层结热力结构不稳定强,非常有利于对流运动,很容易触发大暴雨发生;(3)观测结果表明其维持机制是大暴雨发生在带状长回波带内,超过50 dbz的雷达回波强度稳定少动维持近4 h,导致强降水的持续性。Using the ground observation data,satellite cloud,Doppler radar in Changsha and the GRAPES_Meso3.0 model data,a rainstorm in the north of Hunan province in 2010 is analyzed.It is found out that the environmental conditions of the heavy rain is maintaining low-level shear line and induced surface wind convergence line,a strong vertical upward motion,with abundant water vapor transporting and high instability of energy releasing.The trigger mechanism of the rainstorm is two β mesoscale convective cloud clusters merging to strengthen and stopping to less,resulting in local heavy rainfall.In the strongest stage of the heavy rain,the temperature θ se line forms the structure,and the lower θ se 348 line is warm tongue extending upward to 630 hPa,while the higher θ se as ＂funnel＂ shape,this layer instability is very strong,useful for the convective motion,it occurs heavy rain easily in the heavy rainfall areas of Yue-yang Lin-xiang.The observations datas show that the heavy rain maintenance mechanism is the band long echo band occurs,and more than 50 dbz echos intensity remain stable nearly four hours,leading to persistent heavy rainfall.

关 键 词：天气预报 预报方法 中尺度对流系统 GRAPES_MESO 3.0模式 假相当位温 

分 类 号：P458.121.1[天文地球—大气科学及气象学]