Wang Jingxi: Why did the biggest rainfall in Beijing since 140 years of rainfall appea

Source: Beijing News

Author: Wang Jingxi

On the morning of July 28, Typhoon Du Surui No. 5 this year landed on the coast of Jinjiang City, Fujian Province. Based on a variety of factors, it rarely created an extremely heavy rainfall for inland regions such as North China.From July 29th to August 1st, the violent rain was poured into Beijing, Tianjin, Hebei, and three days, and some regions set off the local rainwater for one year or even two years.

Taking Beijing as an example, this is the largest rain in Beijing since 140 years. The cumulative rainfall has far exceeded the heavy rainstorm of the "July 21" in 2012.The rainfall along the mountains in the southwest of Beijing is particularly large, and the rainwater is gathered into a river, which has led to a serious flood disaster.

the biggest rainfall over the 140s

From July 29th, a strong rainfall covered North China, the flood poured down, the houses and cars were flooded, the warehouse was soaked, and the train was stranded on the track.Ma Xue, the chief forecaster of the Central Meteorological Observatory, has seen the storms from all over China in his work. He uses "extreme" and "rare" to describe the rain.

The heavy rainfall process in North China lasts for more than 72 hours. In the north, the three -day heavy rainfall is very rare.The main flood season in North China is usually mainly based on process rainfall. The duration generally does not exceed two days. Even in 2012, Beijing's "July 21" extremely heavy rainstorm, the duration is only 20 hours.55 hours.This time the rainwater "crazy dumping" for more than 70 hours, bringing the rainfall that is almost equivalent to one to two years.

Taking Beijing as an example, this rain is the largest rain in Beijing in 140 years.According to statistics, from 20:00 on July 29 to 5:00 on August 2nd, the city's average rainfall was 276.5 mm, and the average urban area was 244.9 mm.In the meantime, the largest rainfall in the urban area appeared in Fengtai Qianling Mountain, with 603.6 millimeters. The largest rainfall in the city appeared in the Changping King's Reservoir, with 744.8 millimeters.

According to the Beijing Meteorological Bureau, on July 23, 1891, the Beijing area recorded a heavy rainfall process of 609 millimeters; on July 21, 2012, the maximum rainfall recorded in Beijing was 541 mm.These records have now been refreshed.From 20:00 on July 29 to 7:00 on August 2nd, the Changping Wangjiayuan Reservoir surpassed the historical rainfall pole value recorded in Beijing with a rainfall of 744.8 mm.The first rainfall.

According to the statistics of the meteorological department, two meteorological stations in Beijing have accumulated more than 700 mm.What is this value?The average annual rainfall in Beijing is about 600 mm, which is equivalent to more rain in the past three days in some areas of Beijing than in the whole year.In 2021, Beijing experienced the "long flooding period". The annual precipitation was 698.5 mm, which was 32%more than usual, but it was not as good as the precipitation of Beijing's above two stations in this rainfall.

Beijing -Tianjin -Hebei encounters "train effect"

This extreme heavy rainfall in the Beijing -Tianjin -Hebei region is related to the typhoon "Du Surui" and "Kanu".

At 9:55 on July 28th, Typhoon Du Surui, No. 5 this year, landed on the coast of Jinjiang City, Fujian Province. The residual circulation was entering Henan on the night of the 29th and continued to go north.The Central Meteorological Observatory reminded that the influence of the strongest typhoon in China this year will go deep into the inland and rainfall the rainfall in North China and Northeast China.

Typhoon, as a huge weather system, has a level of about hundreds of kilometers to thousands of kilometers. It is covered with a lot of heat and water vapor.watch for.According to the analysis of the Central Meteorological Observatory, the subtropical high pressure existing on the east side of the "Du Surui" has made the two air pressure gradients very strong. The east wind and southeast wind in the Beijing -Tianjin -Hebei region have significantly enhanced, and the vast water vapor is transported northward.

In addition, during the influence of "Du Surui", the typhoon "Kanu" located on the Western Pacific Ocean also developed development. The strong southeast wind remotely transported the water vapor near the "Kanu" to the North China Plain.Become a rich "raw material" for making heavy rainfall.

In the sea in the eastern part of North China, the subtropical high -pressure stretching west, and a high -pressure spine has gradually moved eastward. On the evening of July 29, the auxiliary high and high pressure on the north side of the Beijing -Tianjin -Hebei side and the high pressure of the mainland."Dam", intercepting the footsteps of the "Du Surui" remnants of the width of the north, and creating conditions for the long time to maintain the heavy rain weather system.It was also the evening of the 29th that rainwater in Beijing and other places began to come.

Affected by the "train effect", the duration of this rain is special.According to the analysis of the Central Meteorological Observatory, the rain in the Beijing -Tianjin -Hebei region was affected by a long -term weather system. Many Rain Cloud Group passed the same place.The effect is intensified.

The wind and the mountain confront each other, forming "maximum rainfall"

If the formation of water vapor and "high -pressure dam" of the two typhoons created "Tian Shi" to the rain, then the Taihang Mountain and the Yanshan Mountains play a "geographical" role.

The abundant water vapor in the north encountered the obstruction of the Taihang Mountain and the Yanshan Mountains.The elevation of the Taihang Mountains is 1,000 meters to 1500 meters. It is an important mountain and geographical dividing line in eastern China. The Yanshan Mountains are 500 meters to 1500 meters.Compared with the tall mountains in western China, these two mountains may not be high, but compared with the vast North China Plain, the height is not small.

When the east wind and southeast wind carrying the water vapor are blocked by the Taihang Mountains, the wind and the mountain encounter have a fierce confrontation.According to the Central Meteorological Observatory, the Taihang Mountains and Dongfeng emergence are orthogonal, and the water vapor is blocked by the terrain, so it is concentrated in the formation of extreme heavy rainfall in the mountains and Qianqian areas.Because of this, Hebei Lincheng, Hebei, and Beijing Mentougou, Fangshan and other places in the mountains will be "violent" rainfall.

The maximum rainfall in the area in the process appeared in Lincheng County, Xingtai City, Hebei Province, reaching 1003.3 mm, which is equivalent to three years of rainfall in Xingtai City in three days;The rainfall reaches 461.4 mm, far exceeding the average level of the city, becoming a area where Beijing heavy rainfall concentration.

The dense rainwater converges into a turbulent river on the ground. Long -term rainwater brushing makes the mountains saturated and softened, and secondary disasters such as mountain floods follow.Beijing Mentougou and Fangshan's key areas of affected areas and roads have been interrupted. At present, communication in some areas has been restored, and road dredging work is ongoing.

"Du Surui" is still the influence, "Kanu" has come

From August 2nd, the northern rainfall has shifted from North China to the area of Northeast China.The Central Meteorological Observatory continued to issue heavy rain blue warnings and strong yellow warnings of the weather at 10:00 on the 3rd. It is expected that from the 3rd to 4th, the warm and humid air flow transported by the subtropical high -pressure periphery, with the influence of the cold air, the northern rainfall was transferred to the northeast area, and the northern rainfall was transferred to the area of the northeast, and and the northern region, and the northern region, and the northeast, and the northeast, and the northern region, it was transferred to the northeast region, and the northern rainfall was transferred to the area of the northeast, and the northern rain was transferred to the area.The duration of precipitation is longer.

The chief forecaster of the Central Meteorological Observatory, Yu Chao, introduced that the precipitation process in the Northeast region has certain extremes.The dynamic lifting conditions, water vapor conditions, and energy conditions of the Northeast region are good, and the energy condition of the vertical wind is changed, which is conducive to the emergence of regional strong precipitation. Some regions will be accompanied by strong convective weather such as short -term precipitation and thunderstorms.At the same time, pay attention to the possibility of tornado.

When people are still lamenting the influence of "Du Surui", Typhoon "Kanu" No. 6 this year has moved into the East China Sea.

At 10:00 on the 3rd, the center of the "Kanu" is located on the East China Sea about 370 kilometers south of the east part of Yuhuan City, Zhejiang Province. The largest wind near the center is 15 (50 meters/s).It is expected that "Kanu" will move slowly west at a speed of about 5 kilometers per hour. It will move and move in the southern part of Zhejiang on the morning of the 3rd to the 4th.Movement, tending to the south of Japan, the intensity gradually weakened.

Whether "Kanu" will change in the later period and land on the coast of Zhejiang and Fujian directly. The current forecast conclusion shows that this possibility is decreasing, but it is expected that "Kanu" will be about 200 kilometers away from the coast of Zhejiang and Fujian in the future.Pay close attention to the impact of the wind and rain in East China when it is near the shore.

In the past 70 years, China's extreme strong precipitation incident has increased

The Blue Book (2023) released by China released in July shows that in the past 70 years (1961 ~ 2022), China's average annual precipitation has increased, and extreme strong precipitation incidents have increased.The frequency of extreme daily precipitation in China is increasing, with an average of 18 stations per 10 years; the annual cumulative rainstorm (daily daily water drop volume ≥ 50 mm) has increased, with an average increase of 4.2%per 10 years.

Scientific monitoring is the same as people's feelings. In recent years, rain and rain have become less, heavy rain and heavy rain have become more, and rainwater has landed on the ground with a more violent gesture.

Similarly in July, the national climate trend forecast of 2023 (July-August) released by the National Climate Center shows that this year's midsummer, China's climate condition is generally to deviation, there are too many extreme weather climate events, and the staged water reduction is reduced., Heavy rain and floods, high -temperature heat waves and other disasters are heavier.Among them, it is expected that the precipitation in Northeast, North China, East China and other places is more than 10 %.

China is now in the main flood season, and extreme heavy precipitation has become the meteorological disaster that is most important at present.It can be seen from the prediction of climate trends in recent years that "deviation" is commonly used, and this is inseparable from the "big background of climate warming".Climate experts have a consensus: the trend of warming the climate system is still continuing, and China is a sensitive area and a significant area of global climate change.

For more than a century, fossil fuel combustion and inequality and unsustainable energy and land use methods have led to 1.1 ° C higher than the level before industrialization before industrialization.This not only causes more frequent and stronger extreme weather events, more severe heat waves, stronger rainfall, and other extreme weather to further exacerbate the risks faced by human health and ecosystems.With global warming, climate change will exacerbate the adverse effects on food safety and water safety.

In terms of climate change, it is an important way to do a prediction of climate trend and prevent prevention.Chao Qingchen, director of the National Climate Center, stated in an interview that climate trend forecasting can be said to exist in production in agricultural production, energy dispatching, material reserves, futures transactions, and economic production.

From March 2021, the meteorological department has begun to release climate prediction results to the public.Meteorological experts said that combined with these tasks, the meteorological department will continue to improve forecasting and forecasting capabilities, and better serve the society in the complex background of increased meteorological disasters.