Causes of Climate Problems Caused by Sandstorms

The hazards of sandstorms are strong winds and dust. Its influence is mainly manifested in the following aspects:

1. Soil wind erosion, vegetation destruction, farmland burial.

2. Polluted air According to the monitoring network of the State Environmental Protection Administration, on the day of the strong sandstorm on March 20, the amount of dustfall per square meter in Beijing reached 20 grams, and the total suspended particles reached 20 micrograms per cubic meter 1 1 000, which was more than ten times the national standard and 1 000 times the normal value.

3. The impact of sandstorms on traffic is mainly manifested in the following aspects: First, the visibility is reduced, which affects driving and aircraft take-off and landing. For example, seven airports in South Korea were forced to close on March 22nd, and about 70 flights were forced to cancel on March 2nd1day. Second, sand and dust bury the roadbed and hinder traffic. According to China Business Daily, the train from Urumqi to Xi was blocked because the sandstorm buried part of the railway.

4. Affect the use and production of precision instruments.

5. There are many kinds of health damage caused by sandstorm, which is harmful to human health. Skin, eyes, nose and lungs are the first places to contact sandstorms and suffer the most. The damage of skin, eyes, nose, throat and other direct contact parts are mainly irritation symptoms and allergic reactions, while the lung manifestations are more serious and extensive. Seven years ago, American health scientists first suggested that there was a link between fine pollution particles and lung disease and heart disease death. Australia's "Time" said that sandstorms caused by soil wind erosion are the chief culprit of asthma in 2 million people in the country.

6. Causing weather and climate changes The impact of this sandstorm not only involves China 13 provinces, but also affects South Korea and Japan; 65438+1September 1998, a sandstorm originated in Kazakhstan, passed through a vast area in northern China, and transported a lot of dust to North America through high altitude; In April of 20001year, a strong sandstorm originated in Mongolia swept across the Pacific Ocean and the continental United States, and finally dissipated over the Atlantic Ocean. Such a large range of dust forms suspended particles in the sky, which is enough to affect the weather and climate. Because suspended particles can reflect solar radiation, thus reducing the atmospheric temperature. Because suspended particles greatly weaken the solar radiation (about 10%), the speed of the earth's water circulation may slow down and the precipitation will decrease; Suspended particles can also inhibit the formation of clouds, reduce the precipitation rate of clouds and reduce the water resources of the earth. It can be seen that dust may aggravate the drought.

Look at the following statistics, let us realize the urgency of preventing and controlling sandstorms. China has 1500 km of railways, 30,000 km of highways and 50,000 km of irrigation canals damaged to varying degrees by sandstorms.

In recent years, the annual direct economic loss caused by sandstorms in China has reached 54 billion yuan, which is equivalent to three times the fiscal revenue of the five northwest provinces 1996.

Scientists have calculated that it will take more than 2,000 years to scrape off 18 cm thick topsoil on a grassland. For example, it takes 49 years to scrape off the same amount of topsoil on corn farmland; On bare ground, it only takes 18 years.

April and May are the high incidence periods of sandstorms in northern China. Please pay close attention to the weather forecast and prepare for sandstorm prevention in advance.

Benefits of sandstorm

Xia Tian, member of the Standing Committee of Chinese People's Political Consultative Conference and executive vice president of the Association for Combating Desertification, reminded that sandstorms are harmful and useless, and people should treat them correctly and actively seek advantages and avoid disadvantages.

Xia Tian said that since April, the number of sandstorms in Inner Mongolia Autonomous Region has been significantly higher than in previous years, which has caused great losses to economic and social development and people's life, especially urban life. But human beings should treat sandstorm weather and sandstorm objectively and treat them correctly. In the face of sandstorm, it is useless to complain, fear and complain, because it is a natural phenomenon that does not depend on human will. The harm of sandstorm is an obvious fact, and we must face it squarely, but everything is divided into two. Sandstorm weather is both harmful and beneficial, so we can't just see its harm without seeing its benefits.

He said that objectively speaking, not all sandstorms bring harm to human beings. Scientific evaluation of sandstorms also has some special positive effects and "good" side. For example, dust not only pollutes the air, but also purifies it. Have you found that the sky with dust settled is the cleanest and clearest after dusty weather and sandstorm? The reason is that the content of calcium in the aerosol formed by dust is high, and dust has a certain neutralization effect on nitrogen oxides, sulfur dioxide and other substances in the air during the falling process, which can effectively reduce acid rain. Dust can also adsorb substances such as industrial smoke and sulfur oxide in automobile exhaust during falling, which not only filters the air, but also inhibits global warming caused by the enhancement of atmospheric greenhouse effect to a certain extent.

In addition, the dust from sandstorm migration made up for the lack of soil in some areas to some extent. For example, sandstorms in the Sahara desert import about130,000 tons of dust into the northeast of the Amazon basin every year, which is equivalent to the annual increase of 190 kg of soil per hectare in this area. The formation of the Loess Plateau in China and the soil in some rocky mountainous areas are also the nature of sandstorms. Moreover, sandstorms swept away the fertile eluvial soil in some places and increased the nutrients in the soil to the landing site.

Summer believes that the scientific attitude towards sandstorms should be to actively seek advantages and avoid disadvantages. The key is to take advantage of the situation to minimize the adverse effects of sandstorms, such as actively planting trees and grass, greening barren hills, reducing land exposure and floating dust, and ensuring that there is no dust or less dust when there is wind. Of course, the control of dust weather is a long-term process, and we must establish the idea of long-term control. No trees will be planted this year, and I look forward to the results next year.

What is the cause of sandstorm?

A: There are many reasons for the formation of sandstorms. The driving force of sandstorm is wind. The material basis is dust. Wind and dust have complex and diverse temporal and spatial changes. There is strong enough wind and enough dust. But blowing a lot of dust also requires many conditions. A strong northwest wind prevails in the arid area of northwest China. Due to the uplift of the ancient Mediterranean, a large number of soft dust deposits were formed. Drought, little rain and sparse vegetation, especially in spring, drought, strong wind and sparse vegetation all occur at the same time, so there are natural conditions for sandstorms in spring, and human activities destroy the vegetation on the ground, making sandstorms worse and worse.

What are the fundamental methods to control sandstorms?

A: Windproof is afforestation. In fact, I have the same view as upstairs. Sandstorms are mainly caused by soil erosion, and all kinds of trees can be stopped. In recent years, according to the statistics of windy and dusty weather in China, sandstorms occurred eight times in 1960s, three times in 1970s 14 times in 1980s14 times, and more than 20 times in 1990s, and the scope became wider and wider, resulting in more and more serious losses. The main gale and sandstorm weather in China since 1990s are introduced as follows:

From April to early May, 1993, windy weather occurred in the north for many times. From April 19 to May 8, Gansu, Ningxia and Inner Mongolia were successively hit by strong winds and sandstorms. On May 5-6, eastern Xinjiang, Hexi in Gansu, most of Ningxia and western Inner Mongolia were hit by severe sandstorms, causing serious losses.

From April 6, 65438 to April 6, 0994, strong winds blew from Mongolia and western Inner Mongolia, and the dust in the northern desert Gobi was lifted by the wind and floated over the Hexi Corridor, and the loess lasted for several days.

1995165438+1On October 7, more than 40 counties (cities) in Shandong were hit by heavy rain, with 35 people killed, 12 1 missing and 320 injured, resulting in direct economic losses of more than 65,438 billion yuan.

1On May 29-30, 1996, 1965, the worst sandstorm swept the west of Hexi Corridor. Black wind suddenly rises, the world is closed, the dust is filled, trees collapse, and people have difficulty breathing. The direct economic losses in Jiuquan area, which suffered the most, amounted to more than 200 million yuan.

1On April 5, 1998, the central and western Inner Mongolia, southwestern Ningxia and Hexi Corridor in Gansu were hit by strong sandstorms, which affected a wide range, including Beijing, Jinan, Nanjing and Hangzhou. On April 19, Tutanto Basin in northern and eastern Xinjiang was hit by a strong wind with an instantaneous wind force of 12, and some areas were accompanied by dust. The devastating typhoon caused a lot of property losses, with 6 people dead, 44 missing and 256 injured. 19 In the early morning of May 1, northern Xinjiang was suddenly hit by strong winds. The wind power in the tuyere areas such as Alashankou and Tacheng reaches 9 to 10, and the instantaneous wind speed reaches 32 meters per second. The winds in other areas generally reach 6 to 7. Strong winds blew down trees and cut off power lines in some areas.

1On April 3rd and 4th, 1999, there was continuous gale and sandstorm weather in Hohhot for two consecutive days. Sandstorms range from the west of Inner Mongolia Autonomous Region to the south of Tongliao City in the east, with instantaneous wind speed 16 meters per second. Maximum wind force in Dalat Banner of Yikezhao League 10.

On March 22-23, 2000, a large area of dusty weather occurred in Inner Mongolia Autonomous Region, and some dust was carried over Beijing by strong winds, which aggravated the degree of sand blowing. On March 27th, the sandstorm hit Beijing again, and the instantaneous wind force in some areas reached 8-9. Seven workers who were working on the roof of a two-story building in Anxiangli Community were blown down by strong winds, and two of them died on the spot. Some billboards were blown down by strong winds, causing pedestrian injuries and vehicle damage.

From 5438+08: 00 on March 6, 2002 to 5438+00 on March 26, 2002, it was a sandstorm weather process with the largest scope, the strongest intensity, the most serious impact and the longest duration since the 1990s. The affected area in northern China reached 1.4 million square kilometers, and the affected population reached1.300 million.

Concept, regulations and standards of sandstorm

First, the concept of dusty weather:

Dust weather is divided into four categories: floating dust, sand blowing, sandstorm and strong sandstorm.

Floating dust: a weather phenomenon in which dust and fine sand float evenly in the air, making the horizontal visibility less than 10 km;

Sand blowing: a weather phenomenon in which the wind blows up dust on the ground, making the air quite turbid and the horizontal visibility is within the range of 1 km to1km;

Sandstorm: a weather phenomenon in which strong winds blow up a lot of dust on the ground, making the air very turbid and the horizontal visibility is less than 1 km;

Strong sandstorm: a weather phenomenon in which strong winds blow up dust on the ground, making the air turbid and the horizontal visibility less than 500 meters.

Second, the classification of dust weather process

Sandstorm weather process can be divided into four categories: floating dust weather process, sand blowing weather process, sandstorm weather process and strong sandstorm weather process.

Floating dust weather process: in the same weather process and at the same observation time, floating dust weather occurred in five or more countries in China's weather forecast area;

Sand blowing weather process: in the same weather process and the same observation time, sand blowing weather occurs in five or more countries in China's weather forecast area;

Sandstorm weather process: in the same weather process, sandstorms occurred in three or more countries in China's weather forecast area at the same observation time;

Strong sandstorm weather process: In the same weather process, more than three countries in China's weather forecast area basically (quasi) stand at the same observation time and have strong sandstorms.

Three, sand and dust weather forecast and early warning standards:

1, decision service

When there is expected to be a sandstorm weather process in the next 24 hours, the sandstorm weather forecast will be released in internal bulletins, special reports and decision-making service materials.

2. Public forecast

National standards:

It is expected that there will be a sandstorm weather process in the next 24 hours, and when it has a great impact or affects Beijing and Tianjin, a sandstorm warning will be issued to the public. ;

It is expected that there will be a sandstorm or strong sandstorm weather process in the next 24 hours, which will cause serious impact and issue a sandstorm warning to the public.

Fourth, the provincial standards:

Determined by the meteorological bureaus of provinces (autonomous regions and municipalities) with reference to national standards;

1, the provincial sandstorm weather forecast and early warning release standard was reported to China Meteorological Bureau for the record.

2. The forecast and early warning of sandstorm weather shall include the area, time, intensity, possible impacts and countermeasures of sandstorm weather.

3. The Central Meteorological Observatory shall promptly and effectively notify the relevant provincial meteorological stations before releasing the forecast and warning of dust weather to the society, and the provincial meteorological stations shall promptly and effectively notify the Central Meteorological Observatory and the relevant meteorological stations before releasing the forecast and warning of dust weather to the society.

Causes and physical mechanism of sandstorm weather

Causes of sandstorm weather:

The weather situation favorable to strong winds or strong winds, favorable distribution of dust sources and favorable air instability conditions are the main reasons for the formation of sandstorms or strong sandstorms. Strong wind is the driving force of sandstorm, and the source of sandstorm is the material basis of sandstorm. Unstable thermal conditions are conducive to the increase of wind power and the development of strong convection, thus carrying more dust and winding it higher.

In addition, drought and lack of rain in the early stage, warming weather and rising temperature are the special weather and climate background for the formation of sandstorms; The convective cells before the ground cold front develop into clouds or squall lines, which is a small and medium-sized system conducive to the development and strengthening of sandstorms. The topographic condition conducive to the increase of wind speed, that is, the narrow tube effect, is one of the favorable conditions for the formation of sandstorms.

Physical mechanism of sandstorm formation;

Under the favorable conditions of large-scale environment, high-altitude dry and cold jet, strong vertical wind speed, wind direction shear and thermal instability stratification, the generation and development of small and medium-scale systems near the front area intensified the pressure and temperature gradient before and after the front area, forming a huge pressure and temperature gradient before and after the front area. Under the joint action of momentum downward transfer and gradient deviation wind, the wind speed in the near-surface layer rises sharply, causing dust on the surface and forming sandstorm or strong sandstorm weather.

Main failure modes of sandstorm

(1) Strong wind: Strong wind accompanied by fine dust damages buildings and public facilities, causing death.

⑵ Sand burial: Farmland, channels, cottages, railways, grasslands, etc. are buried by a large number of quicksand in the form of quicksand, especially posing a serious threat to transportation.

⑶ Soil wind erosion: The dust source and affected area of each sandstorm will be harmed by wind erosion in different degrees, and the depth of wind erosion can reach 1 ~ 10 cm. It is estimated that the annual loss of soil fine matter caused by sandstorms in China is as high as 106 ~ 107 tons, most of which are below 10 micron, which seriously damages the land productivity of farmland and grassland in the source area.

⑷ Air pollution: In the source area and influence area of sandstorm, the inhalable particulate matter (TSP) in the atmosphere increases, and air pollution intensifies. Taking 1993 "5.5" sandstorm as an example, the outdoor air TSP concentration in Jinchang, Gansu Province reached 10 16 mg/m3, and the indoor air TSP concentration was 80 mg/m3, exceeding the standard by 40 times. From March to April, 2000, Beijing was affected by sandstorms, and the number of days when the air pollution index reached Grade 4 or above was 10, which also affected many cities in eastern China. From March 24th to 30th, the daily pollution index of Nanjing, Hangzhou and other cities 18 exceeded Grade IV.

Land desertification only means land degradation. 1992 The United Nations Conference on Environment and Development defined desertification as follows: "Desertification refers to land degradation caused by drought disasters in arid, semi-arid and semi-humid areas due to climate change and unreasonable human economic activities. 1June 1996 17 On the second World Day to Combat Desertification and Drought, the secretariat of the United Nations Convention to Combat Desertification issued a communiqué, pointing out that the phenomenon of desertification in the world is still intensifying. More than 654.38+0.2 billion people in the world are directly threatened by desertification, of which 654.38+0.35 billion people are in danger of losing their land in the short term. Desertification is no longer a simple ecological and environmental problem, but has evolved into an economic and social problem, bringing poverty and social instability to mankind. By 1996, the global desertification land has reached 36 million square kilometers, accounting for 1/4 of the total land area of the earth, equivalent to the total land area of Russia, Canada, China and the United States. There are more than 65,438,000 countries affected by desertification in the world. Although people all over the world are fighting against desertification, it is expanding at a rate of 50,000 to 70,000 square kilometers per year, which is equivalent to the area of Ireland. By the end of the 20th century, the world will lose about 1/3 of cultivated land. Desertification is one of the most serious disasters among many human environmental problems. For people threatened by desertification, desertification means that they will lose the most basic survival foundation-the disappearance of fertile land.