[Explanation] On March 15, affected by the transportation of sand and dust from the upstream, the concentration of PM10 in Beijing increased significantly this morning, and the visibility dropped to below 1 km, resulting in a sandstorm.
In response to this gale and sandstorm, the Beijing Meteorological Observatory issued a blue warning signal for gale and a yellow warning signal for sandstorm.
According to statistics from the Central Meteorological Observatory, this is the most intense sand and dust weather process in China in the past 10 years, and the range of sandstorms is also the widest in the past 10 years.
[Concurrent] Zhang Bihui, Director of Environmental Meteorology Center, China Meteorological Administration
There are two main reasons for this dusty weather. On the one hand, the underlying surface conditions are because the temperature in Mongolia, including Northwest my country, was significantly higher in the early stage, generally higher than 5 to 8 degrees Celsius. The recent precipitation in most parts of Mongolia is relatively scarce, and the surface conditions are very conducive to the occurrence of sand and dust weather.
The second aspect is that under the influence of this relatively strong Mongolian cyclone, from northern Xinjiang to central and western Gansu, most of Inner Mongolia, including northern China, gusts of magnitude 6 to 8 have appeared successively. The occurrence of this dusty weather provides a very good condition for heat and power.
This sandstorm has a very wide range of impacts, including sandstorms and strong sandstorms. It also affected my country’s Northwest and North China. So from the overall intensity, we judged that this process was the strongest sandstorm in the past ten years. The process, at present, has reached the level of a strong sandstorm weather process.
[Explanation] Since March, Beijing has experienced continuous haze and severe sandstorms this time. Why do extreme weather occur frequently?
Is there a connection between the two?
[Concurrent] Zhang Bihui, Director of Environmental Meteorology Center, China Meteorological Administration
Because spring itself is a season of changing seasons. It is the alternating between cold and warm air, which will be more frequent. The haze weather like the previous March since March is mainly due to the entire quiet and stable conditions in the previous period. There is no cold air activity, so on the one hand, there has been such a relatively large-scale warming. On the other hand, there is no such effective systematic precipitation even under this kind of continuous and stable weather. Therefore, the northern region, especially the sand In the source area, the overall precipitation is relatively low, and the soil moisture is relatively dry.
This kind of long-term quietness and no obvious activity of cold air led to the accumulation of this cold air force. Therefore, when the cold air comes down this time, there will be a more obvious confrontation between the cold and warm air masses, forming this Mongolian cyclone. This kind of pressure gradient force is very strong between cold and high pressure, so, correspondingly, this kind of strong wind will cause this kind of sandy weather, so this kind of smog and sandy weather is, to some extent, from In meteorological analysis, there is still a certain degree of continuity before and after.
[Explanation] How to defend and deal with sandstorms?
Zhang Bihui gave suggestions.
[Concurrent] Zhang Bihui, Director of Environmental Meteorology Center, China Meteorological Administration
The impact of sandstorm weather, on the one hand, is that the particles of this kind of sand and dust have a relatively large impact on visibility, and the second is that the particles of sand and dust have a certain impact on human health. On the second aspect, It is the sandy weather, the low visibility caused by it has a relatively large impact on the traffic.
Therefore, when encountering this kind of relatively strong sandstorm weather, it is recommended that the public avoid outdoor activities as much as possible. If outdoor activities are necessary, one is to pay attention to this kind of health protection, and the second is to pay attention to this kind of windy weather. Some effects on this kind of falling objects.
[Explanation] The Meteorological Department reminded that due to the strong cold air, there were northerly winds of magnitude 4-5 and gusts of magnitude 7-8 during the daytime on the 15th in Beijing. The sandstorm will continue until the afternoon of the 15th, and gradually weaken in the evening. Small, visibility improves.
Affected by southerly winds on the 16th, sand and dust may return, and the PM10 concentration increased for a short time.
Dong Zeyu reports from Beijing
Editor in charge: [Ji Xiang]