How often does the rainstorm in Beijing occur?

On the morning of August 2, 2023, the monitoring data of Beijing Meteorological Observatory showed that from 20: 00 on July 29, 2023 to 07: 00 on August 2, 2023, there was extremely heavy rainfall in Beijing. The extreme rainfall recorded in this rainy weather process appeared in Wangjiahuayuan Reservoir in Changping, which was 744.8 mm. According to historical data, as early as July 23 189 1.

This record is the maximum rainfall recorded before this process. On July 2, 20 12, which is still fresh in the public's memory, the maximum rainfall recorded in Beijing was 541mm. According to the Beijing Meteorological Observatory, the extreme value of this rainfall process has greatly exceeded the recorded extreme value of rainfall in Beijing, ranking first in Beijing since the instrumental measurement record of 140.

Cause analysis of rainstorm in Beijing;

As the residual circulation of Typhoon Du continued northward, the rainfall in North China and Huanghuai gradually spread from July 29th, 2023. On July 30th, there was heavy rain or rainstorm in parts of southern Beijing, southern Tianjin, central and southern Hebei, central and northern Henan, southeastern Shanxi and western Shandong. The reason for this rainstorm is that Du itself carries a lot of water vapor, and the subtropical high is on the east side.

This strong pressure gradient between the two will lead to the obvious enhancement of the east wind and southeast wind in Beijing, Tianjin and Hebei. At this time, there is a typhoon "Kanu" in the western Pacific Ocean, and the strong southeast wind will continuously transport the water system near the long-distance "Kanu" to the North China Plain, so the water vapor conditions are very sufficient this time. In addition, the east wind and southeast wind carrying the water system have a certain angle with Taihang Mountain in the west, including the yinshan mountains in the north, so the water system will be blocked by the terrain and concentrated in front of the mountain.