Beijing, April 4 (Zhongxin Net) -- From 11 to 10 April, a wide range of sand and dust weather occurred in Beijing, with the north wind howling, accompanied by sand and dust, and the sky was dusk. According to the official website of the Beijing Ecological Environment Monitoring Center, as of 11 o'clock on the 11th, the primary pollutant in Beijing is inhalable particulate matter (hereinafter referred to as PM9), and the air quality is serious pollution.
On the evening of April 4, Beijing encountered sandy weather, and the scene of the Lama Temple in a sandstorm. Photo/Visual China
At 10:20 on the <>th, foreign sand and dust affected Beijing
According to the Beijing Ecological Environment Monitoring Center, during the day on the 10th, affected by the windy weather behind the Mongolian low pressure, a wide range of sand and dust weather occurred in Beijing. From the afternoon to the night of the 10th, the low pressure system continued to develop to the east, with the influence of the northwest high pressure front, the northwest wind speed was greatly enhanced, the main body of sand and dust entered our Inner Mongolia region in the afternoon, the sand and dust intensity is large, the range is wide, and the speed is fast, and the PM10 concentration generally exceeds 1000 micrograms / cubic meter in a large area affected by sand and dust from the northeast to Gansu, reaching a serious pollution level.
At 10 o'clock on the 20th, foreign sand and dust affected Beijing under the action of continuous strong northwesterly wind, PM10 concentration increased sharply from 1 micrograms / cubic meter to 400 micrograms / cubic meter in 1321 hour, reaching a level 6 serious pollution level, a peak concentration of 22 micrograms / cubic meter appeared at 1384 o'clock, and maintained a very high concentration of 1000 micrograms at night, and by 11 a.m. on the 8th, the PM10 hour concentration was 1102 micrograms / cubic meter, maintaining a serious pollution level.
Upgraded yellow warning for sandstorms and high winds
Beijing Meteorological Observatory upgraded to issue a yellow warning signal for sandstorms at 10 o'clock on the 20th, affected by upstream sand and dust transport, it is expected that from 10 o'clock on the 21th to 11 o'clock on the 17th, there will be obvious sand and dust weather in Beijing, and the minimum visibility in most areas is less than 1000 meters. Upgrade and issue a gale yellow warning signal, it is expected that from now to 11 o'clock on the 17th, Beijing has a northerly wind of about 5 degrees, gusts of 8 and 9, and local areas can reach 10 degrees, please pay attention to precautions.
The meteorological department said that at present, the north wind in Beijing is blowing strongly, accompanied by sand and dust weather, and the minimum visibility in most areas is 1 to 4 kilometers, and it is expected that the north wind is still full power during the day today, and the gusts can reach eight or nine degrees.
It is related to the surface conditions and climatic conditions of the sand source area
According to the Beijing Municipal Ecological Environment Monitoring Center, in March this year, there were frequent sand and dust weather, mainly related to the deviation of surface conditions in the upstream sand source area and the recent abnormal atmospheric circulation. Since last winter, Mongolia has received less precipitation than the same period of the year, and the vegetation cover in the sand source area is poor. In the early spring of this year, the temperature in the arid and semi-arid areas of Mongolia and northwest China was high, the surface thawed early, the sand of the permafrost layer melted rapidly, the surface soil was dry and loose, and the vegetation had not yet grown.
Since March this year, Mongolian cyclones have developed strongly, the temperature has warmed up significantly, and there has been a relatively rare warming weather. Especially after entering mid-March, the vast area from south-central Mongolia to Inner Mongolia encountered more frequent cyclone and frontal system activity. Mongolian cyclones and winds are the "porters" of sand and dust, and under strong wind conditions, sand and dust have been transported to China many times, which is the most direct cause of the occurrence of sand and dust weather in northern China this spring.
Pay attention to bring dust prevention equipment such as masks and scarves
Beijing Municipal Department of Ecology and Environment reminds that from April to May, the risk of sand and dust weather in northern China is greater, please pay close attention to the meteorological department's forecast of sand and dust weather, prepare for wind and sand prevention, close doors and windows in time, and pay attention to carrying masks, scarves and other dust-proof supplies to avoid damage to the eyes and respiratory tract caused by sand and dust; Tighten hoardings, scaffolds, temporary structures and other structures that are easily blown by the wind, and properly place outdoor items that are susceptible to sandstorms; Due to the low visibility, the driver should control the speed to ensure safety. (End)