热低压填塞导致暴雨过程物理量垂直结构分析

The Physical Factor of Vertical Structure Analysis to A Rainstorm Process Caused by Hot Low Pressure

利用FNL（NCEP/NCAR）1°×1°经纬度网格再分析资料,通过4个时次跟踪分析了一次典型西南热低压填塞产生暴雨天气过程的物理量场垂直结构特征,结果表明,西南热低压在填塞过程中,700 hPa以上无明显冷空气扰动,地面有冷空气入侵,由于大气的斜压和非地转的共同强迫作用下,暖空气沿静止锋锋面爬升至800 ～ 600 hPa形成一个较强的辐合上升,垂直上升速度强中心达-2.1 ×10-3hPa/s,同时在550～ 200 hPa存在一个较强辐散下沉,垂直下沉速度强中心达0.9×10-3hPa/s,形成强盛的抽吸效应,构成叠加在基本气流上的次级环流,导致强烈上升运动;大气中高层比低层先增湿;暴雨落区就出现在水汽短时强辐合区;大气中高层先结束水汽辐合输送转为水汽辐散,暴雨结束,大气趋于稳定,热低压填塞.

Using the re-analysis grid datasets of NCEP/NCAR 1°×1°, the physical factor of vertical structure to the weather process of typical southwest hot low pressure packing which caused the rainstorm was analyzed by 4 times tracking, the results are as follows： during the packing of the southwest hot low pressure, the above of 700 hPa had no obvious cold air, but there were cold air on the surface of earth formatting static front; Under the action of common forcing atmospheric baroclinic and non geotropic, the warm air in the south climbed along static front to 800 -600 hPa, formatting a strong ascending area of convergence which center value reached -2.1 × 10 -3 hPa/s, meanwhile, there was a strong ar- ea of divergence sinking in 550 - 200 hPa which center value reached 0.9 × 10 3 hPa/s and caused strong ascending motion and drawing-in effect. Superimposed on the basic flow of the secondary circulation, resulting in strong ascending motion; the air humidity in the high level in- creased early than these in the low level, this result indicated the surface warm air began to coagulate when it climbed to 850 -700 hPa along static front; the rainstorm appeared in the area of steam convergence ; the steam convergence in the high level ended, then converted to steam di- vergence, then the rainstorm ended, the air became stable mad the hot low pressure was packed.