宁夏两次区域性大到暴雨过程的对比分析

Comparative Analysis of Two Regional Heavyto Torrential Rainfall Processes in Ningxia

利用常规探空、地面观测站、自动站及各家数值预报等资料,对发生在2020年8月下半旬的2次区域性大到暴雨天气过程进行了分析。分析表明,2次过程均是在有较明显的高空槽与高空冷空气配合下的混合性降水;其共同的影响系统为500 h Pa高空槽、700 h Pa切变线、低空急流与地面冷锋;不同点是2次过程中副高与大陆高压脊的强度不同,决定了该次过程的低层系统的位置和走向,进而决定了降水落区差异。过程2中,地面有较清楚的锢囚形势出现,但模式检验表明,各模式对锢囚锋的模拟能力有限;可以利用V-3θ图更好地分析对流性降水的发生潜势。

Using conventional radiosonde,surface observation stations,automatic stations,and various numerical forecast data,a comparative analysis was conducted on two regional heavy to torrential rainfall weather processes that occurred in the second half of August 2020.The analysis shows that both processes were mixed precipitation events with the combination of significant upper-level troughs and upper-level cold air.The common influencing systems include a 500 hPa upper-level trough,700 hPa shear line,low-level jet,and surface cold front.The differences lie in the strength of the subtropical high and continental high ridge during the two processes,which determine the position and track of the low-level system and subsequently affect the distribution of rainfall.In the second process,a clear trapped front situation appeared at the surface,but model verification showed limited ability of the models to simulate the trapped front.The V-3θdiagram can be used to better analyze the potential occurrence of convective precipitation.