Beijing, 5 May (ZXS) -- Guilin, Guangxi, was hit by extremely heavy rainfall on 23 May, and roads in many parts of the city were seriously waterlogged. Meteorological monitoring data show that the local hourly rainfall intensity in Xiufeng District of Guilin City reached 22.160 mm, which is comparable to the "6·2021" heavy rainstorm in Zhengzhou in 7 from the perspective of precipitation intensity alone. How strong is this rainstorm in Guilin? What is the reason behind this extremely heavy precipitation?
Tang Qiaoyi, director of the Guilin Meteorological Observatory, said on the evening of the 22nd that the characteristics of short-term heavy precipitation in this process are more obvious, the precipitation period is particularly concentrated, and the hourly rain is particularly strong. According to statistics, from 22 o'clock to 5 o'clock on the 8nd, the three-hour precipitation of the Xiufeng Jiashan Qintan Meteorological Observation Station in Guilin City reached 300.1 mm, and the hourly rain intensity reached 160.6 mm, breaking the historical record of hourly rain intensity in Guilin City.
Compared with the "2021·7" heavy rainstorm in Zhengzhou in 20, from 2021:7 on July 18 to 18:21 on July 0, 200, Zhengzhou experienced a rare sustained heavy precipitation weather process, with the maximum hourly rainfall intensity exceeding 449 mm and the cumulative average precipitation of <> mm.
Tang Qiaoyi said that the average annual precipitation in Guilin is between 1800 mm and 1900 mm. As far as Guilin's extreme precipitation process is concerned, although the daily precipitation of individual stations has reached the magnitude of exceptionally heavy rainfall and broken the hourly rainfall record, due to the vertical and horizontal canals of Guilin rivers, the terrain is high in the north and low in the south, and the rainwater can flow away quickly, and this precipitation process is mainly concentrated in the early morning to 10 o'clock, after which the rain intensity begins to weaken, and the urban waterlogging also quickly recedes, "so the harm of this extreme precipitation process to Guilin is far less serious than that in Zhengzhou."
Talking about the reasons for this extremely heavy precipitation, Tang Qiaoyi said that the extreme heavy precipitation weather is mainly affected by the shear line, the low-level southwest jet stream and weak cold air. The shear line spoke interaction is relatively strong, which provides dynamic conditions for heavy precipitation, and the low-level southwest jet stream is stronger, which provides unstable energy and sufficient water vapor sources for heavy precipitation.
"Importantly, during this process, the cold air from the north and the warm and humid jet stream from the south faced off in the northern Guibei region, and the two sides were 'indistinguishable from the defeat' for a while, resulting in a slower movement of the weather system and a longer stay in the northern Guibei region, resulting in continuous heavy precipitation." He said.
Affected by heavy precipitation, Guilin urban area was seriously waterlogged, traffic was interrupted in some sections, and many local schools were suspended. According to media reports, as of 22 o'clock on the 10nd, a total of 371 schools in Guilin City were suspended, involving 139813 students. Guilin Flood Control and Drought Control Headquarters launched a flood disaster level IV emergency response. At noon on the 22nd, heavy precipitation clouds were far away from Guilin.
Tang Qiaoyi said that due to the influence of the underlying surface, the local nature of precipitation in Guilin is more obvious, and it is necessary to pay attention to the flooding of small and medium-sized rivers and urban waterlogging that may be caused by local heavy precipitation during the flood season. In particular, it should be noted that Guilin's multi-karst landform, if the late precipitation is superimposed, there is a greater risk of disasters such as flash floods, mudslides, and landslides. Industries such as electricity, transportation, and tourism need to guard against adverse effects. (End)