新疆北部冬季暖区大降雪过程中尺度云团特征分析  

Analysis on Mesoscale Cloud Characteristic of Severe Snowfall Process in Warm Zone of Northern Xinjiang Winter

作　　者：赵俊荣[1,2] 杨雪[3] 杨景辉[1,2] 

机构地区：[1]新疆石河子地区气象局,新疆石河子832000 [2]新疆阿勒泰地区气象局,新疆阿勒泰836500 [3]首都师范大学,北京100089

出　　处：《高原气象》2010年第5期1280-1288,共9页Plateau Meteorology

基　　金：新疆气象局科研基金项目"阿勒泰地区暖区大降雪的研究和预报应用"(200011)资助

摘　　要：利用1997-2006年深秋到冬季新疆阿勒泰地区出现的17次暖区大降雪天气过程的卫星云图资料、常规观测资料和地面降雪量资料,并选取其中3次典型的暖区大降雪过程,对暖区大降雪天气过程的中尺度云团演变特征进行了详细分析,进一步揭示暖区大降雪天气的成因。结果表明:500 hPa极涡是造成新疆北部阿勒泰地区暖区大降雪过程的天气尺度影响系统,极涡中心南部或东南部分裂出的中尺度短波是造成暖区大降雪天气的直接影响系统;TBB≤-60℃的中-β和中-α尺度系统云团是造成暖区大降雪天气的主要系统。暖区大降雪的TBB≤-60℃的中-β和中-α尺度系统云团是在绕极涡移动的高空锋区短波槽前和暖平流输送区形成,并位于极涡中心南部或东南部的低层到高层强锋区中,在随着天气尺度云系移动的同时,绕极涡中心逆时针旋转,移速缓慢或稳定少动,移动中逐渐加强或合并,其多表现为椭圆形或圆形,暖区大降雪发生在TBB≤-60℃的中-β和中-α尺度云团边缘TBB等值线梯度最大处。中-β和中-α尺度云团面积越大、生命史越长,造成的暖区大降雪范围就越大、强度也越强;TBB≤-60℃的中-β和中-α尺度云团在阿勒泰地区上空维持数小时可造成阿勒泰地区暖区大降雪天气。Using the satellite cloud image,routine observation data and ground snowfall data of 17 times severe snowfall in the warm zone of Northern Xinjiang from 1997 to 2006,three kinds of the severe snowfall in the warm zone were selected and characteristics of satellite cloud image were analyzed from late autumn to winter in Altay area in order to reveal the cause of severe snowfall in the warm zone.The results show that 500 hPa polar vortex is the synoptic-scale effect system,the mesoscale shortwave from southern or southeastern polar vortex is the direct effect system,and mesoscale-%β% and mesoscale-%α% cloud clusters with TBB≤-60℃ are the main systems causing severe snowfall in the warm zone of Altay area.The mesoscale-%β% and mesoscale-%α% cloud clusters with TBB≤-60℃ are formed in front of the shortwave trough and warm advection belt from the upper-level front zone moving circled the polar vortex,and occur in the strong front zone from the lower to middle levels of the south or southeast of the polar vortex center.With the moving synoptic-scale cloud cluster,the mesoscale clusters float counterclockwise around the polar vortex center and its speed is slowly or stable.During the moving process they strengthen or incorporate gradually and finally form circle or ellipse types.The severe snowfall in the warm zone occur in the most gradient belt of TBB contours in the edge of mesoscale-%β% and mesoscale-%α% cloud clusters with TBB≤-60℃.When the mesoscale-%β% and mesoscale-%α% cloud clusters with TBB≤-60℃ have maintained over Altay area for several hours,that may cause the severe snowfall in warm zone of Altay.

关 键 词：新疆北部 暖区大降雪 中尺度云团特征 TBB 

分 类 号：P426.5[天文地球—大气科学及气象学]