“2013.3.9”宁夏强沙尘暴天气的热力动力条件分析  

Condition analysis of thermal and dynamical characteristics of heavy dust storm in Ningxia on March 9,2013

作　　者：陈豫英[1,2] 陈楠[1,2] 谭志强 李强 聂晶鑫 

机构地区：[1]宁夏气象防灾减灾重点实验室,宁夏银川750002 [2]宁夏气象台,宁夏银川750002

出　　处：《干旱区地理》2016年第2期285-293,共9页Arid Land Geography

基　　金：宁夏科技支撑计划项目2012ZYS160;中国气象局关键技术集成与应用项目CMAGJ2015M66

摘　　要：利用常规气象观测资料和ECMWF逐6h 0.25°×0.25°再分析资料,对宁夏2013年3月9日强沙尘暴暴天气过程的热力和动力条件进行了诊断分析,结果表明:沙尘暴发生前,宁夏上空伴有地表感热通量、6 h变压和变压风及水平螺旋度负值增大、对流层中低层到边界层有明显锋生活动、对流层高层高位涡随高空急流沿等熵面下传到2 000 gpm并形成低空急流等热力和动力因子的变化;强沙尘暴天气出现在地表感热通量增幅超过250 W·m^(-2)、对流层中低层锋生中心超过20×10^(-10)K·m^(-1)·s^(-1)、6 h变压和变压风超过8 h Pa和8 m·s^(-1)、水平螺旋度低于-500 m^2·s^(-2)的区域。Based on the conventional observation data and the ECWMF 6-hourly reanalysis data with a resolution of 0.25°×0.25°,the paper conducted a diagnostic analysis on the dynamic and thermal conditions of severe sandstorm in Ningxia on Mar 9,2013. The results show that the main cause of this strong sandstorm is the cold air intrusion which reached cold wave strength. Under the combined effects of strong sensitive,frontogenesis and the upper and low-level jets,strong turbulent mixing occurred in the boundary layer,producing strong winds and dust ground. Before the sandstorm occurrence,the negative values of the sensitive heat flux on surface,the 6 h surface allobaric,the isallobaric wind and the horizontal helicity increased,meanwhile there were significant frontogenesis activities between the middle-lower troposphere and the boundary layer,and the high potential vortex in the upper troposphere with the upper level jet downloaded 2 000 gpm to be low-level jet along the isentropic surface. Strong sandstorm appeared in the regions where met the following conditions：first,the increase of the surface sensible heat flux was over 250 W·m^（-2）;second,the center value of the frontogenesis in the lower troposphere reached 20×10^（-10）K·m^（-1）·s^（-1）;third,the 6 h surface allobaric was higher than 8 h Pa and isallobaric wind reached 8 m·s^（-1）;at last,the horizontal helicity was lower than-500 m^2·s^（-2）.

关 键 词：强沙尘暴 感热通量 锋生函数 高低空急流 变压风 水平螺旋度 

分 类 号：P425.55[天文地球—大气科学及气象学]