西南地区一次对流复合体调控下的对流层向平流层输送的特征及机制  

Characteristics and mechanism of troposphere-to-stratosphere transport dominated by a mesoscale convective complex in Southwest China

作　　者：施春华[1] 朱锦尧 蔡雯昳 SHI Chunhua;ZHU Jinyao;CAI Wenyi(Key Laboratory of Meteorological Disaster,Ministry of Education(KLME)/School of Atmospheric Sciences,Nanjing University of Information Science and Technology,Nanjing 210044,China)

机构地区：[1]南京信息工程大学气象灾害教育部重点实验室/大气科学学院,江苏南京210044

出　　处：《大气科学学报》2022年第2期302-311,共10页Transactions of Atmospheric Sciences

基　　金：国家自然科学基金资助项目(41875048;41675039)。

摘　　要：利用WRF模式对2009年6月发生在西南地区的一次中尺度对流复合体(Mesoscale Convective Complex,MCC)天气过程进行了数值模拟,结合HYSPLIT拉格朗日轨迹分析,研究了此次强对流天气调控下的对流层向平流层输送(Troposphere-to-Stratosphere transport,TST)的特征与机制。结果表明:1)MCC内对流层顶附近的粒子有两个源区,短期内(6 h内)来源于西南区低层的空气占比很大,随着时间增加(累积到12 h以上),来自北区中高层的空气逐渐增加;前者与MCC及爆发前的西南低空急流有关,后者由北方高空槽后气流引导。2)MCC下方边界层粒子向平流层输送时,分别受周边的两个大尺度系统共同作用。最终24.2%的边界层粒子能进入平流层,其中大部分被MCC强对流垂直迅速向上输送到对流层顶,随后受南亚高压南侧外围环流影响,转而向西移动进入平流层,而少部分是脱离MCC后的粒子,随西南气流向东北输送,遇到中纬度锋面系统,经缓慢的锋面爬升和快速的西风急流共同作用,向东输送到日本上空后进入平流层。The WRF model was used to simulate a mesoscale convective complex(MCC)weather process in Southwest China in June2009.Combined with HYSPLIT Lagrangian trajectory analysis,the characteristics and mechanism of troposphere-to-stratosphere transport(TST)dominated by the MCC were discussed.The conclusions are as follows:(1)There are two source regions for particles near the tropopause in the MCC.In a short time(within6h),most of them come from the lower troposphere over the southwest region,guided by the low-level southwesterly.With the increase of time(accumulated to more than12h),the particles from the middle and upper troposphere over the north region gradually increase,which are guided by the airflow behind the northern upper trough.(2)The24.2% of particles in the boundary layer below the MCC are transported to the stratosphere,which are also controlled by other two large-scale weather systems around them respectively.Most of the particles that finally enter the stratosphere are transported vertically and quickly into the tropopause by the MCC,and then move westward into the stratosphere under the influence of the peripheral circulation on the south side of the South Asian High.A small parts of the particles that finally enter the stratosphere firstly escape from the MCC,and then are transported to the northeast with the southwest airflow,encounter the mid-latitude frontal system,transport eastward over Japan and also enter the stratosphere through the joint action of slow frontal climb and fast westerly jet.

关 键 词：中尺度对流复合体 平流层-对流层交换 对流层向平流层输送 拉格朗日轨迹分析 

分 类 号：P421.3[天文地球—大气科学及气象学]