【Commentary】On March 3, affected by cold air, most of northern China was hit by strong sandstorms. Zhang Bihui, director of the Environmental Meteorological Office of the National Meteorological Center, said that this round of sandstorms is the first strong sandstorm weather process this year.
【During the same period】Zhang Bihui, director of the Environmental Meteorological Office of the National Meteorological Center
(This time) sand and dust weather is mainly developed in the south of Mongolia, and after guiding the air flow south, it affects Inner Mongolia in China, as well as northeast China and northern China. Since the beginning of this year, our country has appeared 6 dust weather processes, the weather process of sandstorms from weak to strong, we are divided into sand weather process, as well as sandstorms and strong sandstorm weather processes, this process is the first strong sandstorm weather process this year.
Zhang Bihui introduced that the formation of this strong sandstorm was mainly affected by two aspects, the temperature in Mongolia and northwest China was generally 5 to 8 °C higher in the early stage, and the precipitation in the above areas was significantly less.
【During the same period】Zhang Bihui, director of the Environmental Meteorological Office of the National Meteorological Center
On the one hand, the temperature in Mongolia and northwest China was generally 5 to 8 °C higher in the early stage, and the precipitation in these areas was significantly low, and the surface was bare and not covered with snow. In addition, recently since March 3, with the development of the Mongolian cyclone, there is a high pressure accompaniment at the back of the cyclone, so there is a strong pressure gradient between the high and low pressure, and the corresponding formation of very large ground gusts, like the northwest region generally appears 19 to 7 gusts, some parts of Inner Mongolia appear gusts above 10 levels, so the windy weather combined with the favorable surface conditions of the sand source, it forms a large area of sand blowing, this sand and dust roll up, under the guidance of this northwest airflow, transmitted to the southeast, Further affect more parts of the country.
Zhang Bihui said that since the beginning of this year, China's sand and dust weather has been slightly more than the same period of the year, but China's sand and dust weather has generally shown a trend of reduction.
【During the same period】Zhang Bihui, director of the Environmental Meteorological Office of the National Meteorological Center
From the current data, there have been 6 times of sand and dust weather this year, which is slightly more than the same period of the year, because the same period of the year is generally 5 times of sand and dust weather. However, from a longer time scale, China's dust weather as a whole is showing a decreasing trend, in the past 5 years on average, we have occurred 12.2 times a year of dust weather process, this data in 2000 to 2010 can reach 15.7 times.
Zhang Bihui said that the formation of sandstorms is greatly affected by geographical and climatic conditions, and China's geographical and climatic conditions are easily affected by sand and dust weather.
【During the same period】Zhang Bihui, director of the Environmental Meteorological Office of the National Meteorological Center
The formation of sandstorms is greatly affected by geography and climate. On the one hand, the bare surface of the underlying surface of this drought will provide a very favorable source of sand and dust, on the other hand, favorable meteorological conditions, the windy weather formed by the intersection of cold and warm air, is conducive to the surface of the dust to be swept into the air, and then transmitted to affect some wider areas downstream. On the one hand, there are a large number of vast sources of sand in the north of our country, especially in the northwest and in neighboring Mongolia. On the other hand, in the spring season, the cold and warm air convergence is more frequent, in the northern region precipitation is relatively rare, the surface is bare conditions, it is very easy to form cold air wind, resulting in the ground dust into the air, affecting the downstream areas, resulting in the formation of this relatively large range of dust weather.
Zhang Bihui reminded that the dust weather has led to reduced visibility and a sharp increase in PM10 concentration, and it is recommended that the public pay attention to traffic safety and do a good job of health protection when traveling.
Dong Zeyu reported from Beijing
Responsible Editor: [Luo Pan]