“七下八上”已过 为何降雨仍频繁？

Group 1 - The Central Meteorological Administration issued a blue rainstorm warning on August 23, predicting two rain belts across China, with the north experiencing rainfall concentrated in North China and Northeast regions, while the south will see significant rain in areas influenced by monsoon currents such as Yunnan, Guizhou, and Sichuan Basin [1] - In Yunnan, heavy rainfall since August 21 has led to the emergency relocation of 4,969 people, with the maximum hourly rainfall recorded at 57.5 mm in Zhaotong [2] - In Qujing, Yunnan, strong rainfall has caused 50 individuals to be trapped, necessitating emergency rescue operations to safely relocate them [3][5] Group 2 - In Shanxi's Yuncheng County, continuous heavy rainfall has resulted in rising river levels, obstructing local villagers' passage due to flooding [6][8] - The meteorological data indicates that during the "July down, August up" period, the national average precipitation has been above normal, with certain regions in North China, East China, and South China experiencing rainfall 50% to 200% higher than the historical average [10] - The persistent rainfall in North China is attributed to the positioning and strength of the subtropical high-pressure system, which has created a conducive environment for frequent rain events [10]