Abstract:Based on the hourly precipitation data of 2 373 national and regional stations from China Meteorological Administration, the extreme characteristics of accumulated precipitation, precipitation intensity and time evolution during the “21·7” (17-22 July 2021) severe torrential rain in Henan Province are analyzed. The results show that this torrential rain process had the characteristics of long duration, large accumulated rainfall, strong abruptness and concentrated torrential rain area. The average accumulated precipitation within 6 days reached 219.05 mm per station, and exceeded 600 mm at 155 stations. There were about 5.43×104 km2 in Henan Province where the cumulative process rainfall was more than 250 mm, larger than that (3.45×104 km2) in the “75·8” (August 1975) process. Three periods of extremely heavy precipitation were from 15:00 BT 18 to 04:00 BT 19, from 09:00 BT 19 to 08:00 BT 21, and from 09:00 BT 21 to 14:00 BT 22 July 2021. The maximum precipitation period occurred from 19 to 21 July, and the rainfall falling area was concentrated in the southeast of Taihang Mountain and northeast of Funiu Mountain. 1 514 stations had at least one time of flash heavy rain (≥ 20 mm·h-1), the large value centers were located in Zhengzhou, Xinxiang and Hebi respectively, with the contribution rate of flash heavy rain in some regions exceeding 70%. The severe precipitation center moved from the central part to northen part of Henan Province from noon of 20 July to the night of the 21 July, and the intensity changed from strong to weak and to strong again. The extremity of the rainstorm process shows obvious local characteristics. The hourly rainfall of Zhengzhou Station at 17:00 BT 20 July was 201.9 mm, exceeding the hourly rainfall intensity of the “75·8” process, and breaking the historical record among the national stations. The maximum rainfall intensity within 3 h and 6 h both occurred at Jiangang Reservoir in Zhengzhou. The total precipitation of Zhengzhou Station in July was 902.0 mm, which is nearly 6 times of the historical average in recent 70 years.