China News Service, Beijing, July 20. Since the 17th, Henan has experienced continuous heavy rainfall, with heavy rains and heavy rains in many places, and extremely heavy rains in some areas.
Monitoring by the Central Meteorological Observatory showed that the rainfall in Zhengzhou reached 201.9 millimeters at 16:00-17:00 on the 20th.
You should know that the rainfall of more than 200 millimeters in 24 hours has reached the level of extremely heavy rain.
Currently, Zhengzhou City has upgraded its flood control emergency response to level I.
Why is the intensity of this precipitation process so large, why is it lasting so long, and what is the impact?
Zhang Ning, chief forecaster of the Henan Meteorological Observatory, made an interpretation of this heavy rain.
On July 20, Zhengzhou, Henan, vehicles passed through a section of stagnant water.
Recently, Zhengzhou has been hit by heavy rains, and the continuous heavy rains have caused serious water accumulation in some streets.
Photo by China News Agency reporter Kan Li
What is the extent of this rain in Henan?
——Heavy rains and heavy rains are seen in most of the province
Zhang Ning said that starting from July 17, Henan has seen a significant precipitation process, and heavy rains and heavy rains have appeared in most of the province.
The heavy rainfall was mainly concentrated in the western, northern and central regions. Extremely heavy rain occurred in Zhengzhou, Jiaozuo, Xinxiang, Luoyang, Nanyang, Pingdingshan, Jiyuan, Anyang, Hebi, and Xuchang.
Why is there such an extreme rainstorm?
——Special airflow characteristics meet Henan's topography
What are the special reasons behind this extremely rare rainstorm, its intensity and duration?
According to Zhang Ning's analysis, the western Pacific subtropical high and the continental high remained stable in the Sea of Japan and northwestern my country respectively, blocking the movement of the upstream system, causing the low-value system of the westerly belt to maintain for a long time in North China and the Huanghuai area.
The long-term precipitation in Henan Province is due to the fact that the precipitation is affected by the deep easterly jet and stable low vortex shear, combined with the strong convergence and uplifting effect of the special topography of the Taihang and Funiu mountains in Henan Province on the easterly airflow. The centers of heavy precipitation are mainly distributed in the mountainous areas in the west and northwest of Henan Province.
Zhang Ning introduced that due to the relatively long duration of precipitation and the relatively concentrated areas where strong precipitation occurs, the risks of mountain torrents and geological disasters in the western and northwestern mountainous areas have increased significantly. The water levels of small and medium-sized rivers and reservoirs in the Yellow River Basin and Haihe River Basin have risen rapidly. It has caused a large area of urban waterlogging and farmland waterlogging.
On July 20, Zhengzhou, Henan, citizens traveled under heavy rain.
Recently, Zhengzhou has been hit by heavy rains, and the continuous heavy rains have caused serious water accumulation in some streets.
Photo by China News Agency reporter Li Chaoqing
What are the characteristics of this precipitation process?
——Long duration, large accumulated rainfall, strong extremes
What are the characteristics of this heavy rain?
In this regard, Zhang Ning analyzed, one is the long duration.
Starting from July 17, Henan Province, the western part of Henan Province, and the central and western regions of Henan Province experienced large-scale heavy precipitation for four consecutive days, and the heavy precipitation will continue.
The second is the large amount of accumulated rainfall.
The province's average rainfall is 113.5 mm, and the average rainfall in Zhengzhou, Jiaozuo and Xinxiang are 357 mm, 210.6 mm, and 194.5 mm respectively.
The largest precipitation occurred in Huancuiyu 728.0 mm in Xingyang City.
The third is the wide range of heavy rainfall.
There are a total of 4,098 rain gauge stations in the province with precipitation exceeding 50 mm, 1923 with more than 100 mm, and 606 with more than 250 mm.
Fourth, the periods of heavy rainfall are concentrated.
The period of heavy rainfall mainly started from the night of the 18th, with torrential rains, heavy rains, and local extremely heavy rains in the northern, central, and western regions.
Fifth, it is extreme.
Songshan, Yanshi, Xinmi, Yichuan, Dengfeng and other five stations broke through the historical extreme value of daily precipitation since the station was established.
Songshan, Gongyi, Xinmi, Yanshi, Dengfeng and other five stations broke through the historical extreme value of accumulated precipitation in the three days since the station was established.
On July 20, Zhengzhou, Henan, a vehicle broke down after passing through a section of stagnant water. Everyone helped push it out.
Recently, Zhengzhou has been hit by heavy rains, and the continuous heavy rains have caused serious water accumulation in some streets.
Photo by China News Agency reporter Li Chaoqing
How was the precipitation in Henan Province in the past 24 hours?
——The average rainfall of the province is 73.1 mm
Regarding the rainfall in the past 24 hours, Zhang Ning said that from 17:00 on the 19th to 17:00 on the 19th, there were heavy rainstorms in most of the province, and extremely heavy rainstorms occurred in Zhengzhou, Xuchang, Xinxiang and other areas.
The province's average rainfall is 73.1 mm, and the average rainfall in Zhengzhou, Xuchang, and Xinxiang are 286.5 mm, 141.5 mm, and 129.6 mm respectively.
There are 2587 rainfall stations with precipitation exceeding 50 mm, 1198 with more than 100 mm, and 311 with more than 250 mm.
The largest precipitation occurred at 584.0 mm in Jiangang, Zhengzhou.
How long will this rain last?
——Heavy precipitation lasted until the night of the 21st
The current rain conditions have worried many people, so when will this torrential rain end?
Zhang Ning said that the heavy precipitation is expected to continue until the night of the 21st. The heavy precipitation area is still in the northwest and central Henan, and the precipitation can reach 100 to 250 millimeters, and locally 300 to 400 millimeters.
From the 22nd to the 26th, there was no obvious large-scale heavy precipitation weather in Henan Province, and there were polydispersive thunderstorms in the province.
(Finish)