Chinanews client, Beijing, March 27th. The sandstorm that disappeared for a few days has made a comeback.

Meteorological monitoring showed that during the daytime from March 27th to 29th, affected by the Mongolian cyclone, a wide range of sand and dust weather will occur in northern my country.

　　The sand and dust weather process will affect about 15 provinces, of which Beijing will be affected by sand and dust for more than 12 hours, and the sand and dust transmission process is expected to stop as far as northern Hubei, Anhui and central Jiangsu.

The Central Meteorological Observatory has issued a yellow warning for sand and dust storms.

National Sand and Dust Weather Forecast Map (20:28, March 27-28, 20:00) Source: Central Meteorological Observatory

15 provinces "besieged" by sand and dust, air quality deteriorated in a large area in the north

　　The satellite cloud picture of the National Satellite Meteorological Center shows that a large area of ​​sand and dust has appeared in Mongolia on the 27th, and the Ulaanbaatar Air Quality (AQI) has exploded. This sand and dust is being transported by strong winds to our country.

　　The Central Meteorological Observatory predicts that from 20: 00 on March 27 to 20: 00 on 28th, the southern Xinjiang basin and east, northeastern Qinghai, Inner Mongolia, central Gansu, Ningxia, central and northern Shaanxi, Shanxi, Hebei, Beijing, Tianjin, northern Henan, Shandong , Midwestern Liaoning, western Jilin, southwest Heilongjiang and other places have blowing sand or floating dust.

　　Among them, there were sandstorms in central Inner Mongolia, northern Shaanxi, northwestern Shanxi, central and northern Hebei, Beijing, Tianjin, western Liaoning, and western Jilin. There were strong sandstorms in the northern part of central Inner Mongolia.

The Central Meteorological Observatory continued to issue yellow dust storm warnings at 18:00 on March 27.

　　From a specific timeline, starting on the afternoon of the 27th, the main body of sand and dust originating from central Mongolia began to enter my country. Most of Inner Mongolia, northwestern Shanxi and northern Hebei were the first to be affected, and the air quality was mainly heavy to severely polluted. .

Inner Mongolia issued an orange warning for sandstorms. Sandstorms occurred in Erenhot and the northern part of Damao Banner in Baotou. The visibility in the northern part of Damao Banner dropped to only 288 meters.

　　On the 28th, it is expected that central Gansu, Ningxia, central and northern Shaanxi, central and northern Shanxi, Beijing, Tianjin, Hebei, and Liaoning will gradually be affected by the transit of sand and dust weather, resulting in large-scale moderate or above pollution; among them, central Inner Mongolia, Shaanxi and Shanxi Most places, most of Beijing-Tianjin-Hebei and other places are located in the main transmission channel of sand and dust, and the air quality is mainly from heavy to severe pollution.

　　From the 29th to the 30th, it is expected that the main body of sand and dust will leave the country via Northeast my country. The remaining sand and dust in North China will continue to be affected by the continued weak northerly wind and continue to move south to affect Shandong and most parts of Henan.

　　Obstructed by large-scale precipitation in the middle and lower reaches of the Yangtze River on the 29th, the sand and dust transmission process is expected to stop as far as northern Hubei, Anhui and central Jiangsu.

Data map: On March 15, Beijing encountered a sandstorm.

Photo by China News Agency reporter Jia Tianyong

Beijing's strong sand and dust weather process will last more than 12 hours

　　This dust attack will be the second dust storm that Beijing has encountered since March.

Zhang Linna, chief forecaster of the Beijing Meteorological Observatory, introduced that the windy and dusty weather in Beijing this time showed three characteristics.

　　The first is the strong wind.

It is estimated that there will be northerly winds of magnitude 4 and 5 in Beijing from midnight on the 27th to the 28th, gusts of magnitude 7 and 8, and gusts of magnitude 8 to 10 in mountainous areas.

　　Secondly, the intensity of sand and dust is relatively strong.

From the middle of the night on the 27th to the 28th, there will be sand and dust weather in Beijing. The intensity of the sandstorm can be reached from the morning to the day on the 28th, and the minimum visibility is about 1 km.

The intensity of the dust weather was slightly weaker than that on March 15. The minimum visibility of the dust storm on the 15th was only 500-800 meters.

　　Finally, the duration is long.

The period of strong sand and dust lasted more than 12 hours from morning to night on the 28th, which was equivalent to the duration of sand and dust on the 15th.

　　After the night on the 28th, the wind decreased, the dust weather gradually weakened, and the visibility improved. The visibility was 8-10 kilometers from the morning to the morning on the 29th.

Affected by southerly winds on the afternoon of the 29th, sand and dust may return, with visibility of 5 to 8 kilometers.

　　The Beijing Municipal Meteorological Bureau initiated a Class IV emergency response to meteorological disasters (sand dust) at 11:30 on March 27. The yellow warning signal for sand and dust storms and the blue warning signal for strong winds are in effect.

Data map: On March 15, Beijing residents wore masks to travel.

Photo by China News Agency reporter Hou Yu

The intensity of sand and dust from Mongolia is slightly weaker than last time

　　This time, the source of sand in the dusty weather is still Mongolia.

　　Zhang Tao, chief forecaster of the Central Meteorological Observatory, said that the main cause of sand and dust is the Mongolian cyclone and the combination of cold and high pressure.

The source of sand is mainly in Mongolia.

　　Continuous monitoring by the National Satellite Meteorological Center of the China Meteorological Administration showed that as of 15:00 on the 27th, sand and dust areas were mainly distributed in eastern and southern Mongolia, western Inner Mongolia, and northern central my country.

It is estimated that the visible area of ​​sand and dust monitored by satellites is about 398,000 square kilometers.

　　Although it is also the sand and dust weather originating from Mongolia, as a whole, Zhang Tao analyzed that compared with the strong sandstorm weather process from March 14 to 18, the intensity of the sandstorm weather process is slightly weaker, and the impact of the sandstorm is not as good. In the east, the range of strong sandstorms is relatively small, and the transmission range of flying sand or floating dust to the south is slightly smaller.

　　Since the impact location is slightly easter than the last time, the impact of sand and dust is more obvious than the last time for the eastern and southeastern parts of Inner Mongolia, Liaoning and other places.

　　"The source of the sand in these two processes is mainly in Mongolia. The causes and meteorological conditions are similar, but the intensity of the Mongolian cyclone and cold high pressure is weaker than the previous one, and the extremeness of the gale is slightly weaker." Zhang Tao said.

Data map: On March 15, in Taiyuan City, Shanxi Province, citizens wear masks outdoors.

Photo by China News Agency reporter Wei Liang

This year's sand and dust weather process is more than usual

Will sand and dust weather become the norm in the future?

　　"Since this year, most of the northern regions have experienced 6 large-scale sand and dust weather processes. This time should be the 7th." Li Liang, a meteorological analyst at China Weather Network, said. 5.3 times of sand and dust weather process, so this year's sand and dust weather process is slightly more.

　　Why is there so much sand and dust this year?

　　Li Liang said that there are many factors for the occurrence of sandstorms, such as bare ground, long-term dryness and little rain, and strong winds brought by cold air.

After a dry and drier climate in winter, my country's Inner Mongolia and southern Mongolia have been in a dry state, and the soil is constantly thawing, coupled with the impact of strong winds brought by cold air, sand will be blown up, forming a dusty weather process.

　　When the last round of sand and dust weather arrived, Zhang Bihui, director of the Environmental Meteorological Center of China Meteorological Administration, once said that such dust weather would not become normal.

　　Data from the National Climate Center show that since 1961, the average number of dust days and dust storm days in the northern part of my country has decreased significantly. Since 2000, the frequency of spring dust and dust storms in northern China has also been lower than that of the same period in normal years.

　　Wang Ji, director of the Beijing Climate Center, also said that according to climate statistics, in March, the annual average (1981-2010 average, the same below) dust days in Beijing Observatory was 2.4 days.

Since the beginning of this year (as of March 26), the Beijing Observatory observed a total of 2 days of sand and dust weather, both of which occurred in March, of which March 15 was a sandstorm.

　　From a longer time scale, the sand and dust weather in Beijing has shown a downward trend year by year.

Most of the dust in the Beijing area occurred in the 1950s and 1960s. The average number of dust days in the 1950s was 18 days, the average number of dust days in the 1960s was 8.9 days, and the average was less than 1 day in the 2010s (only 0.6 days).

(Finish)