The culprit was "it" again!

Author:Beijing Science and Technology Time:2022.06.14

Just the past weekend, Beijing has been frequently taken into precipitation, especially the strong hail weather appeared on Sunday. Who is the culprit behind this?

Article/Reporter Zhao Tianyu New Media Editor/Duan David

"At around 9 o'clock, I was bent outside, and suddenly began to flash thunder, and then the rain fell down." Mr. Jin, who lives in Hufangqiao, Xicheng District, said that after seeing this last night, he hurried to the house. During the period, he watched it. Many private cars rushed against the wind and rain, and hail hail at that time had fallen. He just walked into the door of the building and turned around and looked at the hail of the cherry.

Just in the past weekend, Beijing has been frequently patronized by precipitation, especially on Sunday Pinggu, Miyun, Chaoyang, Shunyi and other areas, with strong hail weather. The maximum hail diameter is 5 cm. Many vehicles and agricultural facilities are damaged. Hail injury.

News from the Beijing Meteorological Bureau showed that from the afternoon of the 12th to the night, there were thunderstorm weather in most parts of Beijing, and the rainfall distributed was extremely uneven. Northeast and Tongzhou northern Tongzhou reached heavy rainfall, and heavy rainstorms. Halm weather appeared in multiple district bureaus. 56 observation stations in the city (9.8%of the total) rainfall exceeds 50 mm, and 7 observation stations (1.2%of the total) rainfall exceed 100 mm. The maximum rainfall appeared at 139.9 mm in Tongzhou Tongshun Racecourse.

Cisaencer: Leng vortex

What are the causes of continuous strong convective weather? The analysis of the Beijing Meteorological Bureau stated that the culprit is the high -altitude and cold vortex system. The cold vortex and the water vapor transmission in the atmosphere. Under the condition of unstable atmosphere, a spiral rain belt is formed against timely clockwise. It brought strong convective weather such as short -term heavy precipitation, hail, and thunderstorms.

Why does the cold vortex form a heavy rain? This is because the temperature in the center of the cold vortex is significantly lower than around, so the cold vortex is also called "high -altitude cold vortex" in meteorology. After the formation of the cold vortex system, the temperature of the high altitude becomes cold, which increases the unstable conditions of the atmospheric environment. Meteorological disaster.

▲ Last night (June 12), Tongzhou District encountered heavy rainy weather (Photo by Bai Jikai)

As for the rainfall of Beijing weekend, due to the lack of sufficient dry and cold air involvement on the 11th, the strong pairing weather is basically mainly in short -term heavy rainfall, and the scope of influence is relatively limited.

On the 12th, due to the cold vortex rotation process, the high -altitude brought obvious dry cold air, resulting in further increase in high and low air temperature differences. The rapid development and strengthening of the storm have caused disaster weather such as hail in many places in Beijing.

Why does the thunderstorm in Beijing prefer June

Cold vortex rainstorm is a rainstorm formed under the control of cold vortex. The cold vortex every spring and early summer in Inner Mongolia and Northeast my country are frequent, and they often repeatedly pass or affect the area of this area. According to data, more than half of the strong weather in the Beijing -Tianjin -Hebei region occurred in the background of the cold vortex.

For example, the 7.21 heavy rain in 2012 and 7.20 heavy rain in 2016, especially the former, were produced in the background of the cold vortex movement.

▲ Miyun encountered hail weather in many places

For Beijing, which has an average annual precipitation of less than 800 mm, the three months of the three months of July, 7, and 8 accounted for almost half of the year. Among them, June is often the month with the highest thunderstorm ratio. Why do thunderstorms prefer June? This is actually closely related to the influence of cold vortex.

Different from thunderstorms in July and August, due to the warm and humid air flow in the south, the consistency of the region will occur in Beijing. Under the influence of cold vortex in June, local rainfall was very obvious. And it is usually accompanied by lightning, heavy wind, hail and other weather phenomena.

▲ Vehicles damaged by hail on June 12th

In fact, the precipitation of Beijing weekends is well reflected in the three words "locality". The precipitation data shows that the average rainfall in the city is 18.8 mm, but the city's average rainfall is 18.8 millimeters, but the northwestern regions The rainfall is only 6.4 mm, and the southwestern region is only 1.0 millimeters. It can be said that a "fake rain" is said to be as high as 139.9 mm in Tongzhou with the largest rainfall, which is more than 6 times higher than the average.

Cold vortex heavy rain forecast is difficult

Compared with other weather systems, the cold edge rainstorm weather is highly disaster, such as strong sexuality, strong convectivity, small rainfall, small -time precipitation, such as the hail weather on Sunday without monitoring relevant information. Therefore, the forecast of cold vortex is difficult.

Sun Jun, the chief forecaster of the Central Meteorological Observatory, explained that the diameter range of the cold vortex system is mostly more than 500 kilometers, so the precipitation weather is widely distributed on the surface. In this system, the hot and cold contrast is relatively strong, and the distribution of unstable state is not distributed. Uniform, the trigger conditions of trigger precipitation are not uniform, which is the reason why the cold edge rainstorm is strong.

▲ Fengyun satellite map shows that the cold vortex entrusted in the Beijing -Tianjin -Hebei region has gradually moved eastward (Source: China Meteorological Bureau)

"Under the influence of the same system, it may be raining in Hebei, and there is no Beijing in Beijing; the North Fifth Ring Road in Beijing is raining, but the South Third Ring Road is a light rain." Therefore, it is necessary to use satellite observation, radar observation and other means to strengthen the forecast in short -term approaching the short -term approaching time. forecast.

Forecast weather, forecasters are still judged based on numerical forecasting, which is also the basis of weather forecast. Secondly, it is based on the concept model of rainfall producing rainfall, and further judgment is combined with the high and low altitude configuration. However, numerical forecasting is very complicated. The subtle deviation of observation data will be magnified in future computing calculations. Therefore, the longer the prediction of the timeliness, the greater the error may be. Leng vortex brings is not only bad weather

Cold vortex weather does not definitely bring rainfall, depending on the cold vortex, but also depends on the cooperation of low -level weather systems. After the cold vortex from Inner Mongolia and Northeast China to the North China Plain, a relatively strong vortex system appears at the low -level. In order to cooperate, it can cause weather conditions to meet the heavy rain. In addition, it is also related to the latent heat release generated by precipitation.

If there is not enough precipitation conditions, the cold vortex will bring people a refreshing cool breeze. It can dispel heat in summer. In the autumn, it is good at creating a high -value weather of blue sky and white clouds. The beauty index is five stars.

At the intersection of summer and autumn in Beijing, the high altitude is greatly affected by the cold vortex of the Northeast, the coldness is obvious, and the transparency of the atmosphere is very high. The ground is still mainly blowing the southwind, which will bring sufficient water vapor from the ocean. Such a favorable water vapor condition, coupled with the radiation heating effect in the summer afternoon, is easy to form a differential flow. The beautiful off -season cloud and the strongy clouds are at the time of the flow of flowing clouds.

▲ The cold vortex impacts the good weather brought to Beijing (pictured: Zhao Tianyu)

Strengthen the warning of cold vortex weather forecasting, and the meteorological department is also actively conducting scientific research: On April 5, 2022, the Central Meteorological Observatory, Shenyang Central Meteorological Observatory, and Northeast Cold Vortex Research Office jointly released the first period of "Northeast Cold Vortex Monitoring Forecast". The live monitoring, forecasting, and service prompts of the path and strength. The cold vortex has a formal number and obtained a grand "treatment" similar to typhoons.

This is the first time in China to release a bulletin, which not only has important value significance to improving the cold vortex of the Northeast and its high impact on weather monitoring, forecasting, and service capabilities. It also provides strong support for disaster prevention and mitigation affected by the cold vortex. Development and application, continuously improve the technical capabilities of forecasting.

(Part of the information in this article is integrated from Qianlong.com, Beijing Daily, China Weather Network, etc.)

Produced: Popular Science Central Kitchen