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Original title: The strongest sandstorm to hit Beijing in the last 10 years. Visibility is less than 1 km. The China Meteorological Administration answers all questions: Seat belts have very little impact on sand and dust weather.
Every reporter Li Biao Every editor Chen Xing
On March 15, a sky full of yellow sand swept over Beijing. For a time, photos of the Beijing sandstorms swept the internet.
Monitoring by the Central Meteorological Observatory showed that from March 14 to 15 floating sand or dust appeared in many parts of the north, sand storms occurred in Beijing, northern Hebei, northwest Shanxi, central and western Mongolia Inland and western Gansu and local areas. with a visibility of less than 500 meters. There were strong sand storms; Gusts of magnitude 6 to 8 occurred in northern Xinjiang, central and western Gansu, most of Inner Mongolia, northern China and western north-east China, and winds of magnitude 10 to 11 occurred in the eastern Xinjiang and parts of central and eastern Inner Mongolia.
Starting at 7:25 AM on the 15th, Beijing updated its yellow dust storm warning sign. The city was on the blue and yellow dust warning advisory, and the visibility was less than 1 km.
This is the strongest sand and dust meteorological process that has affected our country in the last 10 years.
What is the cause of this sandstorm? Why couldn’t the protection belt stop the sandstorm? Will sandstorms normalize?
At the press conference held by the China Meteorological Administration on March 15, reporters from the “Daily Economic News” asked experts from the China Meteorological Administration on these issues.
Xinhua News AgencyBeijing’s PM10 concentration exceeded 8000
On March 15, the 9 o’clock data released by the Beijing Ecological Environment Monitoring Center showed that the concentration of PM10 in the six districts of the city was 8108 μg / m3, 6877 μg / m3 in the northwest, 3461 μg / m3 in the northeast and 5953 μg / m in the southeast, cubic meters, 7530 micrograms / cubic meter in the southwest.
The sandstorm didn’t just sweep through Beijing.
Zhang Bihui, director of the China Meteorological Administration’s Environmental Meteorological Center, said that on the 15th and 16th, the central and eastern regions of my country were affected by this northern air current. Therefore, the dusty weather process will affect the central and eastern regions. regions of my country from north to south. Judging from the sand and dust climate that has occurred, the impact of the sand and dust climate is very large and affects Northwest and North China. In terms of intensity, this process is the strongest sandstorm process in the last 10 years. At present, it has reached the level of strong sandstorm meteorological process.
It is understood that the sand and dust climate is divided into five levels: floating dust, blowing sand, sandstorm, strong sandstorm, and extra strong sandstorm. Zhang Bihui believes that there are two main reasons for the severe dust storm in Beijing: in terms of the underlying surface conditions, because the temperature in Mongolia and northwest China was significantly higher in the initial stage, generally 5 to 8 degrees Celsius. In addition, Mongolia Recent precipitation in some areas is relatively low, and surface conditions are very conducive to dusty weather; on the other hand, affected by the strong Mongolian cyclone, there have been 6 to 8 levels in northern Xinjiang, central and western Gansu, most of Inner Mongolia and northern northern China The gust of wind provided very good thermal and dynamic conditions for this sandy and dusty climate.
“The dusty weather in Beijing this time is due to the combination of the above two reasons, especially the intensity of the Mongolian cyclone. This is not normal weather,” said Zhang Bihui.
The refuge forest has little impact on the sand and dust climate
According to the State Forestry and Grassland Administration, the dust weather mainly affected 221 counties (cities, districts and banners) in 10 provinces (autonomous regions and municipalities) in Xinjiang, Inner Mongolia, Gansu, Ningxia, Shaanxi, Shanxi, Hebei, Beijing. , Tianjin and Liaoning.), With a population of about 64.17 million people. The affected land area is about 1.32 million square kilometers, including about 7.48 million hectares of arable land, about 12.86 million hectares of forest land, and about 59.26 million hectares. grassland.
Why couldn’t the “Three North” protection belt prevent the strong sandstorm from heading south?
Zhang Bihui believes that during the transmission process, Beijing was downstream under the influence of dust and air masses, so there was a very severe pollution climate. “Because the protection belt has a very limited impact on the entire wind field. Compared to the strong weather process, its impact is also very low and basically negligible. Therefore, the impact of the protection belt on the wind and therefore in the sand and dust is very small, “said Zhang Bihui.
Zhang Bihui further explained that the impact of the protection belt on the wind field is very small on a large scale, but it will have a certain impact on the local, close to the ground and small-scale wind fields. Safety belts have a positive effect on wind protection and fixation to the sand. On the one hand, through tree planting and afforestation, the sand-fixing and water-storing effects of vegetation roots inhibit sand formation. On the other hand, the refuge forest will reduce the local flying sand caused by the local wind field.
It will not be in Beijing-Tianjin-Hebei
According to Zhang Bihui, spring is a frequent season prone to sandy and dusty weather. There are two main reasons: one is that as the temperature gradually increases, the surface begins to thaw and the dust particles are easy to pick up; the other is that spring cyclonic weather is gradually activated and dynamic conditions are prone to sand and dust weather.
At the same time, Zhang Bihui pointed out that from the current surface wind field forecast, the south wind weather appeared mainly on March 16, so the impact of the return of sand and dust will have some impact on Beijing. . By the 17th, the entire wind direction turned to the east. Also, there was more obvious precipitation weather in the lower reaches of the Jianghuai area, so the dusty weather will not change back and forth in Beijing, Tianjin and Hebei for a long time.
For defense against sandstorms, the China Meteorological Administration recommends that residents stay indoors with doors and windows closed as much as possible, especially the elderly, infants and young children with little resistance, and people with allergic respiratory diseases. If you must be outdoors out of necessity, avoid riding your bike as much as possible. Use wet towels and gauze to protect your eyes, nose, and mouth. It is better to wear dustproof clothing, gloves, face masks, glasses and other items. .
At the same time, the China Meteorological Administration reminded that if you are outdoors, stay away from trees and billboards, crouch against a solid low wall that can avoid wind and sand, lie down on a relatively high slope downwind or grip a solid object. In case of chronic cough with sputum or shortness of breath, episodic wheezing, and chest pain, seek medical attention as soon as possible.
