溪洛渡水电站2次暴雨过程对比分析

Comparative Analysis of Two Rainstorm Processes at Xiluodu Hydropower Station

利用MICAPS常规、自动站、探空站等资料,从天气特点、环流背景、物理量特征等方面对金沙江溪洛渡水电站2020年8月8日和2021年9月4日2次暴雨天气过程进行分析。结果表明:2次暴雨发生前500 hPa东亚中高纬度地区均呈两槽一脊形势,都是“两高”辐合型,受到低涡切变的影响;过程前都存在大气层结不稳定,具有较高的能量但未得到释放,坝区温度都高于32℃,CAPE值都较高,K指数都达到了42以上,SI指数均小于-2.5。但“8·08”辐合系统更明显,强对流、雷暴突出,局地性强,短时雨强大,持续时间长,而“9·04”低涡更明显,降雨区域性强,持续时间较短。

Based on the data of MICAPS conventional,automatic and radiosonde stations,the two rainstorm weather processes of the Xiluodu Hydropower Station on the Jinsha River on August 8,2020 and September 4,2021 are analyzed from the aspects of weather characteristics,circulation background,physical quantity characteristics,etc.The results showed that 500 hPa before the occurrence of the two rainstorm,the middle and high latitudes in East Asia were in the situation of two troughs and one ridge,both of which were convergence type,and were affected by vortex shear;Before the process,there was instability in atmospheric stratification with high energy but not released.The temperature in the dam area was above 32 ℃,and the CAPE value was high.The K index reached above 42,and the SI index was less than-2.5.But the “8·08”convergence system was more obvious,with strong convection and thunderstorms,strong locality,strong short-term rainfall,and long duration,while the “9·04” vortex was more obvious,with strong regional rainfall and short duration.