The rain concentrates on one day a year! The mystery behind the ＂typhoon＂ rainstorm in Beijing and Hebei

　　Recently, Beijing and Hebei were hit by heavy rain, and it rained cats and dogs, which made people unprepared. This severe meteorological phenomenon is inextricably linked with Typhoon Du Surui, which is unbelievable. According to the data released by the Central Meteorological Observatory, it is estimated that the rainstorm will last for several days, and the rainfall even exceeds the annual average of previous years, so the situation is worrying.

　　Why did Beijing and Hebei become the "hardest hit areas" of this "typhoon" rainstorm? Why is the rainfall in Beijing always so fierce? To explore the mystery behind this, we have to understand the geographical term "Beijing Bay" first.

　　"Beijing Bay" is located at the northernmost part of North China Plain, surrounded by Taihang Mountain and Yanshan Mountain. Affected by the monsoon climate, the precipitation distribution in Beijing is extremely uneven, and 70%~75% of the annual precipitation is concentrated in summer. Usually, the heavy rain in July and August every year is mostly caused by subtropical high (commonly known as "subtropical high"), and this extreme weather is related to the northward movement of subtropical high and the blocking of residual low pressure.

　　So why is the rainstorm caused by the subtropical high especially in this area of Beijing Bay? The reason is closely related to the geographical characteristics of Beijing Bay.

　　"Beijing Bay" is a small plain formed by the intersection of Taihang Mountain and Yanshan Mountain, which has been chased along the water and soil here since ancient times. Surrounded by mountains on three sides and Ma Pingchuan in the southeast, it is a solid geographical treasure trove. The precipitation in North China was blocked by Taihang Mountain and Yanshan Mountain, which formed the precipitation process.

　　Historically, Beijing is a city that thrives on water. During the Yuan Dynasty, Jishuitan provided a vast water area for Beijing and became the origin of the central axis. During the Ming and Qing Dynasties, Beijing followed the pattern of the Yuan Dynasty, and the Haidian area was built by water. Royal gardens such as the Summer Palace and Yuanmingyuan became places for emperors' government affairs and leisure because of their rich aquatic resources.

　　However, water also brings troubles. Most of the ancient Yuan Dynasty was called "Kun City" because the city walls were not rainproof. Today, the ancient buildings of the Forbidden City use sewers to drain water in a strange way, making it a miracle that there has been almost no backwater for hundreds of years.

　　Typhoon "Du Surui" and the imminent attack of "Kanu" made Beijing Bay continuously subjected to the test of heavy rain. This heavy rain has made people more aware of the importance of "helping each other in the same boat". In the face of natural forces, we need to unite as one and cope together.