It’s a saline-alkali dust storm in Beijing, not a sandstorm.
"Beijing is not a sandstorm, it is a saline-alkali dust storm! Accordingly, sand control should be changed to dust control. " Zheng Baiyu, Secretary General of the Ecological Poverty Alleviation Committee of yenching university Beijing Alumni Association, reported this unique view at the third Sino-Korean seminar on desertification control and grassland protection in 2006.
Zheng Baiyu has lived in Xilin Gol grassland for many years. After retiring in 1999, he continued to engage in ecological and environmental protection activities in grassland, especially in recent years, he has carried out many years of scientific research and control practice on the harm of saline-alkali dust storms caused by the drying up of Chagannuoer Lake, and has his own unique views on the dust storms.
The dry Lake Chagannor is the source of dust storms.
Zheng Baiyu told the Science Times reporter that Chagannuoer Lake with an area of 110 square kilometers is located at the junction of the northern edge of Hunshandake Sandy Land and Xilin Gol Grassland, roughly 600 kilometers north of Beijing. Gogestai River, the source river of Chagannuoer, originates from Hunshandake Sandy Land. In the past two or three decades, the weather has become hotter and drier, and the Gogsitai River has become less and less, and it is often cut off, resulting in the Chagannuoer Salt Lake drying up in the spring of 2002.
"Since the summer of 2002, I have invited Han Tonglin, a researcher at the Chinese Academy of Geological Sciences, Song Huailong, a researcher at the Institute of Oceanography of the Chinese Academy of Sciences, and other experts, scholars and environmental protection volunteers to conduct on-the-spot investigations and investigations, and found that the dust storm caused by the dry Lake Chagannor is different from the sandstorm we generally know, and the dust it carries contains a lot of saline-alkali substances."
Zheng Baiyu said that the sight seen in Chagannuoer Lake is shocking: the dry lake basin is full of white saline-alkali dust, which is very fine and loose, and you can raise smoke when you step on it. Salinity will even crystallize in wet places and become saline-alkali ice flowers. Loose saline-alkali dust will be raised when the wind is not very strong. Generally, when the wind is 5 ~ 6, almost pure saline-alkali dust rises locally in the lake basin, and a white saline-alkali smoke covers the lake basin area. Sometimes the saline-alkali dust is rolled into a column of smoke like a tornado and rises very high. When the wind increases to 7 ~ 8, even the dust rolls up and becomes a strong mixed dust storm of saline-alkali dust.
The sandstorm often mentioned is actually a saline-alkali dust storm.
"From the situation of Chagan Noel, the sandstorm we are talking about now should be a dust storm in essence, and it is a dust storm rich in saline-alkali substances. The dust of the saline-alkali dust storm is very slight, rising very high, and will enter the atmospheric circulation and be transported to far places. From the path of dust storm, it affects Beijing, Tianjin and North China. Without intervention, the Chagannuoer dry lake basin will also evolve into a desert or sand. "
Zheng Baiyu pointed out that the research conclusion of Chagannuoer and the understanding of saline-alkali dust storm are quite different from the traditional sandstorm theory in China. The traditional sandstorm theory focuses on the physical parameters such as power source, material source, path, harm, prevention and control, and there are two big indexes that are not involved or not well expressed-the relationship between the particle size of sandstorm inclusions and sandstorm movement, and the chemical composition of sandstorm inclusions and its influence.
Han Tonglin believes that it is of great significance to determine the particle size of dust entrained by sandstorms. In layman’s terms, it is necessary to determine whether the components of sandstorms affecting eastern China are mainly "sand" or "dust", and to determine the birthplace. "If it is sand, the focus of work is on controlling sand sources; If it is dust, treat the dust source. "
According to Han Tonglin, the granularity of sand and dust is different. Under the same wind, the finer the particles, the higher they rise and the farther they are transported. "According to the classification method in China, the classification standard of soil mechanical composition is 8 grades, namely gravel, extremely coarse sand, coarse sand, medium sand, fine sand, extremely fine sand, silt and clay. When the wind speed is 15m/s (level 7), the floating distance of 0.1mm fine sand is 4.5 ~ 45m, and the floating height is less than 8m. The floating distance of 0.01mm silt is 45 ~ 450 kilometers, and the floating height is below 800 meters. In the sampling of eight deserts in China, fine sand accounts for 85.6%, medium sand accounts for 11.6%, and the rest is coarse sand. It is unfounded to think that desert is the material source of sandstorms. "
In addition, the sand in the desert and the dust in the sandstorm are not only a matter of particle size, but also have different movement forms, settlement locations and prevention methods.
Han Tonglin said: "If we distinguish the size of dust particles in sandstorms, we can find that the current measures to prevent and control sandstorms are inappropriate-for curbing dust storms and controlling dust storm sources, the role of afforestation is limited. It can neither stop dust storms in Beijing, Tianjin and North China, nor is it the best means to restore the ecology of dust source areas, especially in the desert areas that have been formed. It is a waste of national financial resources."
Song Huailong believes that the current standards and definitions cannot fully reflect other attributes of sandstorms. "Generally speaking, it is not clear what the chemical composition of sand and dust substances is and the impact of these components on people’s lives, social activities and ecological environment. According to the source, movement and environmental impact on human beings and ecology, dust storms can be divided into physical dust storms and chemical dust storms. The toxicological effect of chemical dust storms is a part worthy of special attention. "
The chemical dust storm has been verified by experiments.
For the viewpoint that sandstorms in China are chemical dust storms, several researchers provided experimental data.
A research team of Beijing Normal University made a laboratory analysis on the components of the extraordinarily serious sandstorm in Beijing on March 20th, 2002, and wrote a paper entitled "Saline soil source of dry salt lake of sandstorm in Beijing", saying that "the surface soil of the arid and semi-arid areas where sandstorm passed through including dry salt lake and saline soil is also its main source".
The Institute of Geology, Chinese Academy of Geological Sciences, analyzed the dry dustfall in Beijing on April 16 this year, and the results were almost the same as those of the research group of Beijing Normal University. According to the results of electron microscope scanning and chemical analysis of water-soluble salts at room temperature, the dust storm in Beijing on April 16 was a chemical dust storm. The results of particle size and content measurement by scanning electron microscope show that 96% of the particles are smaller than 0.074mm, and 4% are smaller than 0.154mm and larger than 0.074 mm. The pH value of dust is 7.9, which is alkaline. The structure, geochemical characteristics and the detection results of water-soluble salt at room temperature show that the composition of dust is basically the same as that of soil samples in dry saline lake basin, but different from that in Hunshandake sandy land and degraded grassland, indicating that the dust in Beijing on April 16 mainly came from dry saline lake basin.
Saline-alkali desert and chemical dust storm are universal problems in western China.
Most of China’s salt lakes and dry saline-alkali lake basins are concentrated in the west, and there are 813 salt lakes with an area of nearly 40,000 square kilometers. All the saltwater lakes have more than 100,000 square kilometers, and if the dry lake basins are included, it is much larger than this figure. Some of these saline-alkali dry lake basins are close to North China, Beijing and Tianjin. In addition, there are about 500 million to 600 million mu of saline-alkali land in China, and most of them are distributed in the west of China.
Zheng Baiyu believes that the phenomenon of saline-alkali desert and chemical dust storm has a profound geographical and geological background. The western part of China is located in the easternmost part of the North Africa-Eurasia desert belt, which is an ancient ocean in ancient times. Since Cenozoic Tertiary, the ancient ocean has begun to shrink back. In the process of evolution, two noteworthy phenomena appeared. First, a large amount of salt in the ocean and saltwater lake remained in the soil during the drying of the lake and sea. Because part of the salt became alkali through alkalization, these soils became saline-alkali soil. Second, large areas of dry sea basins and lake basins have appeared in inland sea and lakes. The sediments in dry sea basins and lake basins are deep, fine and rich in saline-alkali substances. "Some deserts in China are in basins, such as the Taklimakan Desert in the Tarim Basin, which is the result of this evolution. This explains why most sandstorms in China are caused by saline-alkali dust storms. "
Zheng Baiyu believes that although the chemical dust storm is mainly caused by natural causes, it also has a lot to do with unreasonable human activities, especially the unreasonable use of water resources by human beings, which has an incalculable impact on the environment.
Controlling chemical dust storm with salt-tolerant pioneer economic plants
Because the views of researchers such as Zheng Baiyu and Song Huailong have not been recognized by the competent authorities of the state, they have not been supported by the state. However, they started the research and experiment of comprehensive management with their own funds-planting saline-alkali tolerant pioneer economic plant Suaeda salsa to cover the bare grassland saline-alkali spot desert, so as to achieve the purpose of fixing dust and suppressing alkali. The experiment was carried out in Chagannuoer dry lake basin in Ximeng, Inner Mongolia and Angulino dry lake basin in Hebei. After four years of exploration, the experiment has achieved phased results. Based on the experiment of artificial planting of 1000 mu in Chagannuoer in 2003, the coverage area of Suaeda salsa has been expanded to about 10000 mu, of which more than 900 mu have a coverage rate of over 85%. The average plant height is about 60cm；; The average plant weight is 225g g. In this 10000-mu Suaeda salsa coverage area, it can be preliminarily judged that it has basically the effect of dust fixation and alkali suppression, that is, it has shown the ecological control effect of little or no saline-alkali dust in strong wind.
Several researchers, including Zheng Baiyu, also put forward suggestions for controlling chemical dust storms. First, reform the management system. Preventing and controlling chemical dust storms is a systematic project involving many departments and disciplines, which should be led by an organ that can command, synthesize and coordinate all departments, and is not suitable for a professional department. Second, intensify research, with the national authorities taking the lead in organizing or designating specialized research institutions to carry out research on the evolution of dry lake basins and the prevention and control of chemical dust storms, and collect relevant information as soon as possible; The third is to improve the national monitoring system and testing projects; Fourth, continue the dust source control project; The fifth is to grasp several big projects and experimental projects; Sixth, we are determined to adjust the production mode and production structure of grassland animal husbandry, transform family pastures, implement intensive grassland animal husbandry and build new pastoral areas.