Why do sandstorms always occur in spring?

Audit expert: Ye Haiying

Deputy Director of the New Media Center of the Meteorological Publicity and Science Center of the China Meteorological Administration (China Meteorological News Agency)

"Where is spring? Where is spring? Spring is in the green mountains and forests. There are red flowers, green grass, and little orioles that can sing..."

Source: Baidu

Spring is a season full of vitality and vigor, with flowers blooming and birds singing. But for some people, spring also has a less wonderful name - "eating dirt season".

Whenever the spring breeze blows, it seems that the whole earth is preparing a "sand and dust feast" for us.

According to a paper published by the Chinese Academy of Meteorological Sciences in April 2023, in the past 20 years, based on data collected from 673 meteorological stations, China experienced 297 sandstorms, of which 77.8% occurred in spring.

Source: Paper on the causes and control measures of sandstorms in northern China

So why do sandstorms always strike us in spring? What natural laws are behind this phenomenon?

1

Let us uncover this mystery together!

Source: Baidu

The formation of sandstorm weather does not happen overnight. It involves the interweaving of multiple factors, among which local sand sources and long-distance transportation are two key elements.

Local sand sources refer to those areas that directly provide the material basis for sandstorms. These areas usually have dry and loose soil conditions, sparse vegetation cover, and weak resistance to wind erosion.

When there are strong winds, sand and dust in these areas may be blown up by strong winds to form sandstorms.

Source: Baidu

my country's northern regions, especially desert and semi-desert areas, such as the Hunshandake Desert and Badain Jaran Desert, are important local sand sources.

Although local sand sources are the direct source of sandstorms, the role of long-range transport cannot be ignored. Under the influence of strong winds, sand and dust particles can be transported to areas far away from the source area, and this transportation process may involve hundreds or even thousands of kilometers.

This long-range transport not only affects the scope and duration of sandstorms, but may also have serious impacts on the environment and air quality in areas along the way.

In some cases, local sand sources and long-range transport may work simultaneously to cause sandstorms in a certain area.

The reason why spring is a peak season for sandstorms is closely related to the following factors.

Source: Baidu

Climate factors : Sandstorm weather is the product of atmospheric circulation and local natural environment. Sand sources, strong winds and unstable stratification are necessary conditions for its occurrence, among which strong winds and unstable stratification provide the driving force. When cold air moves southward and meets warm and humid air, strong winds often form. In addition, after the surface thaws in spring, the soil becomes loose and more easily eroded by wind, which is also one of the reasons for the frequent occurrence of sandstorm weather.

Source: Baidu

Geographical factors : There are many deserts and Gobi in northern China. The surface cover in these areas is sparse, and the sand is exposed. When the spring wind comes, the exposed sand is easily blown up by the wind, forming sandstorms. At the same time, some terrains such as valleys and basins are also prone to localized sandstorms.

Source: People's Daily Online

Human factors : The occurrence of sandstorms is indeed related to human activities, but it is not decisive. Natural conditions themselves are the determining factors for the occurrence of sandstorms, and human activities only play a role in strengthening or weakening sandstorms. For example, engineering construction such as road construction and mining will damage the surface and increase the probability of sandstorms.

2

Will future sandstorms become weaker or stronger?

Schematic diagram of the Earth System Model of the Chinese Academy of Sciences

Source: Chinese Academy of Sciences

At present, the Earth System Model (ESM) CMIP5 and CMIP6 can be used to consider human emission scenarios such as representative concentration pathways (RCPs) and shared socioeconomic pathways (SSPs), and the possible changes in future sandstorms can be indirectly obtained by predicting future meteorological elements related to sandstorms such as temperature, wind speed, precipitation, soil moisture, etc.

Source: China Meteorological Disaster Yearbook

According to data from the National Climate Center, my country has continuously stepped up its efforts to prevent and control desertification over the past 20 years, and the area of ​​desertified and sandy land has continued to decrease and the degree of desertification has continued to decrease. In addition, the National Forestry and Grassland Administration predicts that the number of sandstorms in northern my country in spring 2024 will be 9 to 12 times, which is close to or slightly less than the same period in normal years.

This is due to the continuous advancement of my country's ecological governance work, such as the implementation of measures such as returning farmland to forests and returning pasture to grassland, which have effectively improved the condition of surface vegetation and reduced the occurrence of sandstorms.

It is understood that the National Forestry and Grassland Administration has recently made arrangements for emergency response to sandstorm disasters in 2024. In the next step, it will strengthen international cooperation in ecological protection and restoration of sandstorm source areas and desertification prevention and control, and scientifically promote desertification prevention and control. At the same time, it will improve the emergency response capabilities for sandstorm disasters, strengthen departmental cooperation, and jointly carry out sandstorm disaster monitoring, early warning and emergency response work.

With the continuous advancement of science and technology, I believe that in the future we will be able to better predict and prevent sandstorms and create a more livable environment for people.

References:

China Meteorological News: Top 10 weather and climate events in China in 2023

China Meteorological Science Academy: Playing a leading role and fulfilling the mission

Causes of sandstorms in northern China and countermeasures