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Improving visibility in Beijing tomorrow may bring sand and dust back
Minimum visibility is expected to be 1,000 meters; the meteorological department issued a yellow warning for sand and dust storms; Visibility is expected to improve on the 29th, but sand and dust may return.
Today there will be a sandstorm in Beijing, which is expected to last more than 12 hours. Compared to the sandstorm on March 15, the intensity is slightly weaker and the duration is the same.
The reporter learned yesterday from the Beijing Meteorological Office that strong winds and sandstorms are expected in Beijing from midnight on the 27th to the 28th. On the 28th, the intensity of the sand and dust will reach the level of storms of sand, with a minimum visibility of about 1,000 meters. The Beijing Municipal Meteorological Office successively issued blue sandstorm warnings and yellow sandstorm warnings.
The duration of the sand and dust is expected to exceed 12 hours.
The Beijing Meteorological Observatory issued a blue warning signal for gale on the 27th. Affected by the cold air, it is estimated that from 2 am to 8 pm on the 28th, there will be north winds of magnitude 4 and 5 in most from areas of Beijing, with gusts of magnitude 7 and 8, and gusts of magnitude 8 to 10 in mountainous areas.
On the same day, the Beijing Meteorological Observatory also issued a yellow warning signal for sand and dust storms. Sand and dust weather is expected in Beijing from midnight 27-28, of which there will be a sandstorm on the 28th, with a minimum visibility of about 1,000 meters.
Zhang Linna, chief forecaster with the Beijing Meteorological Observatory, told reporters that monitoring data showed that a wide range of sandstorms occurred in Mongolia yesterday morning. As the Mongolian cyclone moves east and south, sand and dust will travel along the east-northwest path, bringing a large area of sand or dust storms to the north of my country, and there will be strong winds and sandstorms in Beijing.
In this round of sand and dust weather, the period of heavy sand and dust lasted more than 12 hours from morning to night on the 28th. Compared to the sand and dust weather of March 15, the intensity was slightly weaker and the duration was the same. .
In addition, Zhang Linna said that the dusty weather will be accompanied by strong winds. It is estimated that from midnight on the 27th to the 28th, there will be magnitude 4 or 5 north winds in Beijing, with gusts of magnitude 7 to 8.
Sand and dust can return in the afternoon of the 29th.
The wind will subside after the night of the 28th, the dusty weather will gradually weaken, and visibility will improve. Visibility is expected to recover to 8-10 kilometers from the morning to the morning of the 29th. However, affected by the south wind on the afternoon of the 29th, there may be an ebb of sand and dust, which will cause the sand and dust that have been swept south return to the city of Beijing. There will be weak and dusty weather at that time, and visibility will decrease, within 5-8 kilometers.
The Municipal Meteorological Office recalls that the intensity of sand and dust in Beijing mainly depends on the intensity of sand and dust in the upstream river and on the transmission route. There are certain uncertainties in today’s sand and dust intensity forecast, and citizens are asked to pay attention to the latest monitoring, forecasting and early warning information.
Follow-up 1
Where did the dust in Beijing come from this year?
The reporter learned from the Beijing Meteorological Observatory that the sand and dust in Beijing are mainly caused by the transportation of sand sources outside of Beijing, such as Mongolia and Inner Mongolia. Since the beginning of winter last year, most sand source areas have reduced rainfall compared to the same period in normal years, and the surface is basically not covered with snow. The large-scale bare surface has provided sandy source conditions for spring weather dust.
From February to February, the middle and high latitudes of Europe and Asia adjusted to a zonal circulation, the high Siberian pressure weakened, the temperature in the north increased significantly and the soil was dry, which was conducive to sanding. Recently, the mid-to-high latitude circulation has undergone drastic adjustments, Siberian high pressure has increased, and cold air activities have become more frequent. The lower layers of Beijing have been affected by strong winds from the northwest, creating favorable conditions for transportation. of sand and dust.
Follow-up 2
Has the dusty weather in Beijing increased in recent years?
According to the competent person in charge of the Beijing Meteorological Observatory, the average dust days from January 1 to March 31 was 3.1 days (average from 1981 to 2010). Since 2000, the maximum number of days is 10, which happened in 2002 and 2001, and it will be 1 day in the same period in 2020.
From the beginning of this year, to March 26, a total of 2 days of sand and dust weather have been observed, both of which occurred in March, of which March 15 was a sandstorm.
Most of the dust in the Beijing area occurred in the 1950s and 1960s. Generally speaking, the dust climate has been decreasing year after year. The average number of dust days in the 1950s was 18 days, and the average number of dust days in the 1960s was 8.9 days before this century. The 10-year average is only 0.6 days.
The average number of dust days in March in history was 2.4 days, and the maximum number of days in 2001 occurred in 2001. Since March of this year, there have been 2 days starting from the 26th. 16, sandstorms occurred on the 15th. During the same period, the sandstorm occurred on March 11, 1995 in March of the most recent year.
Follow-up 3
Why is Beijing prone to dusty weather in spring?
According to Peng Yingdeng, a researcher at the National Research Center for Urban Environmental Pollution Control Technology, the period from March to May is a period of high incidence of sand and dust. According to the climate statistics of previous years, the recent appearance of sand and Dusty weather in Beijing is a normal phenomenon, but its degree varies from year to year.
There are two main conditions for sandy and dusty weather: windy weather, bare surface, and dry. In spring, the temperature rises and the topsoil melts. Also, there is little rain at this stage and the climate is dry, and the surface vegetation has not fully recovered. Once exposed loose soil encounters a strong wind, it will be rolled up and dusted, resulting in a sandstorm or even a sandstorm.
In addition, each spring, Beijing is also vulnerable to sand and dust transported from Mongolia, my country’s Inner Mongolia, Northwest China, and other regions. This is also the main source of sand and dust in Beijing. Mongolia has many desertified areas and a great shortage of seasonal rains. The sand and dust climate has been frequent. Every year, half of the sandstorms in Mongolia affect China. Passing through the arid regions of the northwest, they will also carry away the fine local dust particles., Evolved in a climate of high intensity sand and dust, the distance can reach thousands of kilometers. Some time ago, the severe sandstorm that occurred in Beijing in the last ten years was caused by the overlap of overseas imports and the local climate of sand and dust.
■Advice
Guide for protection against dust and sand
Based on the information issued by the National Health Commission, National Emergency Broadcasting, Beijing Municipal Health Commission and Beijing Municipal Landscape Architecture Office, the reporter resolved a guide for the protection of citizens against sand and the dust:
● Reduce outdoor activities and it is not recommended to open windows to ventilate.
● Pay attention to fire prevention when sweeping the Qingming Festival
● Do not rub the powder in your eyes.
● Remember to wear an N95 mask when you go out
● Moisturize the skin and protect the skin properly.
● Four lights should come on when driving
● Stay away from tall buildings, billboards, and temporary structures, and watch out for falling objects (reporter Huang Zhecheng Yingyue Zhang Lu)
【Correction error】
【Editor in charge: Gu Yue】
