不同天气影响形势下首都国际机场雷暴的空间分布及移动特征

Study on thunderstorm characteristics over the capital international airport of diurnal and spatial distribution and moving under different weather situations

利用2008—2014年(2010年除外)的实况探空资料和首都机场雷达资料,研究了发生在首都机场的雷暴的时空分布特征及不同移动特征,并分类研究了不同天气影响形势下的空间分布和移动特征,结果表明:影响首都机场的多单体雷暴主要来自西部和西北部的山区,而单体雷暴在平原形成的最多;多单体雷暴自西北-东南移动和自西南-东北移动的数量相当,而单体雷暴自西南-东北方向移动的较多。多单体与单体雷暴的平均移动速度均为43 km·h-1,多单体以西北-东南方向移动的最快(45 km·h-1),而单体雷暴以西-东方向的平均移动速度最快(57 km·h-1);除了西南-东北方向的多单体和单体的平均移动速度相近外,其它方向的单体雷暴移动速度均快于多单体雷暴。山区雷暴的主要时段为03—13UTC(世界时,下同),峰值出现在傍晚前后(11UTC),主要由西北-东南方向移动(占总数的77%);山坡上的雷暴最大峰值出现在07UTC和10UTC,集中在2个区形成,在西南山坡上形成的雷暴全部由西南-东北方向移动,而在西北山坡上形成的雷暴主要由西北-东南方向移动;平原雷暴主要集中在07—13UTC,峰值出现在09UTC,产生在山脚平原上的雷暴由西-东移动,其它的则由西南-东北方向。将雷暴按不同的影响系统划分后可发现,西风槽类和低涡类雷暴均以西南-东北方向移动最多;西北气流型与横槽类雷暴主要以西北-东南方向移动为主。西风槽类和横槽类雷暴出现在平原上最多,大部分由西南-东北方向移动;西北气流型雷暴出现在山区最多,大部分由西北和正西方向向东南方向移动;低涡类雷暴从山区移来与平原上形成的雷暴数量相当,山区移来的雷暴由西北-东南方向移动,在北京南部平原形成的雷暴及由移入的雷暴由河北省西南-东北方向移动。在西南-东北方向移动的雷暴中,以低涡型雷暴的移动速度最快(55 km·h-1),移动最慢的是西风槽型(39 km·h-1);在西北-东南方向移动的雷暴中,西风槽和横槽型移动速度最快(50 km·h-1),其次为西北气流型(42 km·h-1)和低涡型(41 km·h-1)。西风槽类雷暴以西北-东南方向移速最快;西北气流型的雷暴西南-东北方向和西北-东南方向平均移速相近;低涡类雷暴西南-东北方向的平均速度快于其它方向。

Using sounding and radar data at the capital airport from 2008 to 2014 （except for 2010）, the diurnal and spatial distribution and moving characteristics of thunderstorms happened over the capital international airport were studied. The results show as follows. Firstly, the multicell thunderstorms come mainly from the west and northwest mountain areas, while single-cell thunderstorms were generated in the plains. Meanwhile, the number of multicell thunderstorms moving from northwest to southeast is the same as that of thunderstorms moving from southwest to northeast. Most single-cel l thunderstorms move from southwest to northeast. Both average moving speed of multicell and single-cell thunderstorms are 43 km/h. But the multicell thunderstorms which move from northwest to southeast are the fastest （45 km/h） among all multicell thunderstorms. The average speed of the single-cel l thunderstorms moving from west to east are the fastest （57m/h）. Ex-cept that the average speed of the multicell thunderstorms moving from southwest to northeast is the same as that of single-cell thunderstorms, the moving speed of those from other directions are faster than that of multicell thunderstorms. The main period of the mountain area thunder-storms, which mainly move from northwest to southeast, is 03-13UTC, with the peak value appearing around the early evening （11UTC）. The maximum peaks of thunderstorms that concentrate on two slope areas are 07UTC （15BT） and 10UTC （18BT）, respectively. The thunderstorms generated on the southwest slope all move from southwest to northeast, while the thunderstorms on the northwest slope mainly move from northwest to southeast. The plain thunderstorms mainly occur during 07-13UTC, with the peak appearing at 09UTC. The thunderstorms on the foot of the mountain move from west to east, while the others move from southwest to northeast.Secondly, after classing different situations, it is found that the thunderstorms which are triggered by westerly trough and low vortex mostly move from southwest to northeast, but the thun-derstorms which are triggered by northwest airflow and cross trough mainly move from northwest to southeast. The westerly trough and trans-verse trough thunderstorms occur mostly on the plains, and move from southwest to northeast. The northwest airflow thunderstorms mostly oc-cur in the mountains, and move from northwest or west to the southeast. The number of thunderstorms that are triggered by low vortex generate in the mountains and the plains are the same, but the thunderstorms from the mountains move from northwest to southeast, and the thunder-storms generated in the south plain move from southwest to northeast. Among the thunderstorms that move from southwest to northeast, the vortex thunderstorms move the fastest （55 km/h）, followed by the northwest airflow type（44 km/h）, and the slowest type is westerly trough （39km/h）. Among the thunderstorms moving from northwest to southeast, the westerly trough and transverse trough type move the fastest （50 km/ h）, followed by the northwest air flow type （42 km/h）, and the vortex type （41 km/h） moves the slowest. Among all westerly trough type thunder-storms, the thunderstorms moving from northwest to southeast are the fastest. Among the northwest airflow type thunderstorm, the average speed of the thunderstorms moving from southwest to northeast and from northwest to southeast are similar, while the average speed of the thunderstorm triggered by the vortex moving from southwest to northeast is faster than those from other directions.