What are the natural causes of sandstorms?

Question 1: What are the natural and man-made causes of sandstorms? Human resources are environmental pollution, deforestation and land desertification. Dust and dust are roughly the same.

Question 2: The main cause of sandstorm is a disastrous weather phenomenon in which wind and sand interact. Its formation is closely related to global greenhouse effect, El Nino phenomenon, sharp decline of forests, vegetation destruction, species extinction, climate anomalies and other factors. Among them, over-exploitation of natural ingot source, over-cutting of forest and over-reclamation of land caused by population expansion are the main reasons for frequent sandstorms.

Question 3: What are the main causes of sandstorms? "Rich dust sources, strong winds and extremely unstable atmosphere are three indispensable factors that cause sandstorms. The latter two are mainly related to meteorological conditions, while the former is related to land desertification. Therefore, although land desertification is not the main factor causing sandstorms and their changes, it is a serious logging factor, so we must never ignore the control of land desertification. " ?

Haha, does Qian Zhengan, a sandstorm expert, sometimes make mistakes? ! !

Sandstorm, no doubt, is caused by desertification of the land! ! There is an absurd saying that "land desertification is not the main factor causing sandstorms and their changes"! !

Can you still blame the airflow? The shortage in New Zealand is extremely high. Air flow is a natural phenomenon. Land desertification is man-made. It is caused by our current wrong practices: grassland desertification and land desertification. The past: the wind blows and grass sees cattle and sheep, and now quicksand is everywhere. A mistake is a mistake. Don't hide it. If it is not changed, it will bring irreparable disaster to future generations.

I can see the level of "expert" now.

Question 4: The main reasons for the formation of sandstorms "Rich dust sources, strong winds and extremely unstable atmosphere are three indispensable factors that cause sandstorms. The latter two are mainly related to meteorological conditions, while the former is related to land desertification. Therefore, although land desertification is not the main factor causing sandstorms and their changes, it is an important factor, so we must never ignore the control of land desertification. " ?

Haha, does Qian Zhengan, a sandstorm expert, sometimes make mistakes? ! !

Sandstorm, no doubt, is caused by desertification of the land! ! There is an absurd saying that "land desertification is not the main factor causing sandstorms and their changes"! !

Can you still blame the airflow? The shortage in New Zealand is extremely high. Air flow is a natural phenomenon. Land desertification is man-made. It is caused by our current wrong practices: grassland desertification and land desertification. The past: the wind blows and grass sees cattle and sheep, and now quicksand is everywhere. A mistake is a mistake. Don't hide it. If it is not changed, it will bring irreparable disaster to future generations.

I can see the level of "expert" now.

120 Respondent: cfzpfei- 9th grade Jinshi.

Question 5: What is the next sentence in the desert? The vast desert is lonely, and the Yellow River sets the yen.

Xiao Guan rides every time, and everyone is in Yanran.

Question 6: The main cause of sandstorm is a weather phenomenon in which wind and sand interact, that is, strong wind blows up dust on the ground, which leads to a sharp decrease in atmospheric visibility. There are various reasons, both natural and human, such as global greenhouse effect, El Ni? o phenomenon, sharp decline of forests, destruction of vegetation, species extinction, abnormal climate and other factors. Among them, over-exploitation of natural resources, over-logging and over-reclamation caused by population expansion are the main reasons for the formation of sandstorms, which increase the intensity and frequency of sandstorms.

As a kind of high-intensity sandstorm disaster, sandstorm can't happen in all windy places, but only in those areas with dry climate and sparse vegetation.

Sandstorms mostly occur in April-May every year, taking northwest China as an example. At this time of year, the Hawaiian high is formed in the Pacific Ocean, the Indian low is formed in the Asian continent, and the strong south wind blows from the ocean to the land. The Mongolian high, which controls the mainland, began to move from west to north, where cold and warm air currents met, and the heavy Siberian cold current came quickly from west to east, often forming strong winds. The wind force that forms sandstorms is generally above 8, and the wind speed is about 25 meters per second. In addition, the formation of sandstorms requires sufficient sand sources, and dust can be blown off the ground by the wind. The northwest is deep inland, and the forest coverage rate is not high. Most of the surface is desert and grassland, and there are many sandy wasteland, which provides conditions for the formation of sandstorms. Moreover, poor northwest people also want to make a fortune by digging licorice, holding seaweed and mining. These predatory acts of destruction further aggravated the sandstorm disaster in this area. * * * The land is easily rolled up by strong winds to form sandstorms or even strong sandstorms.

In the natural state, sandstorms are generally small in scale. However, due to people's excessive cultivation and overgrazing of grassland, a large area of grassland has become wasteland, increasing the frequency and intensity of sandstorms. In the 1930s, during the development of the Great Plains in the western United States, a large number of forests and grasslands were cut down, resulting in a large area of grassland turning into a desert, which triggered three famous "black storms". According to a black storm that swept across the North American continent in 1934, it was estimated afterwards that about 300 million tons of fertile soil was blown away at that time, and the amount of dust falling in Chicago reached12.42 million tons a day.

There are many hazards of sandstorm: 1, people and animals die, buildings collapse and agricultural production is reduced. Sandstorms are as harmful to people, animals and buildings as typhoons and tornadoes. 1On May 5, 1993, a serious sandstorm occurred in four provinces in northwest China, resulting in 85 deaths and 3/kloc-0 missing, with direct losses as high as 540 million yuan. 1August, 999 14 Since the early morning, moderate-intensity sandstorms have appeared in Dunhuang and other areas in Hexi Corridor, Gansu Province. The instantaneous wind speed reaches 14 meter per second, and the visibility is between 200 and 300 meters. Sand and stones are flying like dusk, (casualties are still being counted). In the past five years, the northwest of China has been hit by sandstorms for more than 20 times, resulting in economic losses of more than 654.38+0.2 billion yuan, and more than 200 people have died and disappeared.

2. Air pollution and topsoil loss. Dust storms contain at least 38 chemical elements, which greatly increase the concentration of atmospheric solid pollutants and cause long-term and potential harm to the atmospheric environment, soil and agricultural production in the origin, surrounding areas and downwind areas. Especially after the meager topsoil on which crops depend is scraped away, the barren land will seriously affect the yield of crops.

The most important way to prevent and control sandstorms is to increase the vegetation coverage on the surface. Specifically, planting trees and grass and fixing sand. Since the founding of New China, the Three-North Shelterbelt connecting Northeast China, North China and Northwest China has planted trees and grass on the edge of the desert, which has played an important role in preventing and controlling sandstorms. According to the statistics of Yulin City, located in the north of Shaanxi Province, due to years of planting trees and grass, sandstorms have been reduced from 66 days a year in the 1950s to 5 days a year now.

Question 7: There are three main causes of sandstorm: strong wind, sand source and unstable air.

strong breeze

Persistent strong winds are the dynamic conditions for the formation of sandstorms. For example, it is observed that when a strong sandstorm is formed, if the wind speed reaches 30m per second (11wind), coarse sand (0.5 ~ 1.0mm in diameter) will fly out of the ground for several tens of centimeters, while fine sand (0. 125 ~ 0.25mm in diameter).

Shayuan

China is one of the countries with the most deserts in the world. Northwest China, North China and Northeast China are places where deserts and sandstorms are concentrated. The desert and sandy land here covers an area of over 700,000 square kilometers. Various sand dunes in the desert can be divided into mobile sand dunes, semi-fixed sand dunes and fixed sand dunes according to their stability. When sandstorms often occur, the amount of dust raised by moving dunes is the largest, the semi-fixed dunes are smaller, and the fixed dunes are the smallest.

Except desert and sandy land, most of northern China belongs to mid-latitude arid and semi-arid areas, and the ground is mostly sparse grassland and arid cultivated land, with sparse vegetation and serious man-made damage. In spring, when the ground warms up and thaws, the ground is filled with dust when the wind blows, forming dusty weather in the local area and the area where the wind passes.

Unstable air

Let's look at an example in life first. When you fiddle with the stove, the fire burns brightly. With a slight poke, ash will often fly all over the house. When the fire goes out, you usually don't spend much effort to raise dust, which involves the problem of air stability. After the fire is extinguished, there is little difference in air temperature between the top and bottom of the stove, so the air is stable. When the fire burns violently, the air near the fire is hot, and the air far away from the fire is cold. Hot air is lighter than cold air and tends to rise, so the air above the fire is unstable. In this way, the stirred furnace ash can easily rise with the hot air and then float all over the room.

In nature, so do sandstorms. If the lower air temperature is low and stable, the dust blown by the wind will not be lifted very high; If the lower air temperature is high, it will be unstable and easy to move upward. After the wind blows, the dust will be blown high, forming a sandstorm. In fact, sandstorms in China are usually strongest in the afternoon or from afternoon to evening, because this is the most unstable time of the day.

In addition to the above three factors, human production activities and other factors are also very important to the formation of sandstorms. Such as man-made destruction of vegetation, industrial and mining traffic construction, large-scale construction and other damage to the surface, provide fine dust for the occurrence and development of sandstorms.

China satellite meteorological expert system analyzes six characteristics of sandstorm.

According to the China National Satellite Meteorological Center, at the recent academic annual meeting of the China National Satellite Meteorological Center, Dong Chaohua, chief engineer and researcher of the National Satellite Meteorological Center, Fang, Zheng Xinjiang, Lu Naimeng, Professor Shao Yaping of the University of New South Wales, etc. 17 people participated in the study of the China sandstorm project, and predicted its occurrence time, region, source, path, related factors, six characteristics of impact and numerical model.

1. Time: Sandstorms in China mainly occur from March to April. Taking 2002 as an example, there were sandstorms 12 times in China, including 4 strong sandstorms, all of which occurred in March and April. All the above processes were monitored and analyzed by the National Satellite Meteorological Center.

2. Geography: Sandstorms mainly occur in east longitude 1 10-north latitude17 degrees, that is, the vast area north of 38 degrees north latitude, that is, taking Cangzhou, Hebei as the boundary, reaching Tianjin and Beijing to Inner Mongolia in the north, passing Shijiazhuang, Yinchuan, Lanzhou and Qilian in Qinghai in the west, and reaching north.

Source: The main source of sandstorms in China is Mongolia and even the desert areas in Central Asia. This kind of sandstorm is strong, and its influence is obviously greater than that of sandstorm in China. The source of China is the Hexi Corridor in Gansu, southern Inner Mongolia, northern Hebei and other desert areas.

Four. Path: In recent years, especially last spring, there are four main paths of sandstorms affecting Beijing: one is the path of Mongolia-Inner Mongolia-Beijing turning to the northeast. The second is the route from Hexi Corridor to Beijing. Third, it influences Beijing from Zhu Rihe in Inner Mongolia via Zhangjiakou in Hebei. The fourth is to influence Beijing from the northern plateau of Shanxi to the east.

Verb (abbreviation of verb) related factors: According to 1998, especially since 2002, the main dust processes and related climatic factors in Huahua area.

Question 8: What are the natural and man-made causes of sandstorms? Human resources are environmental pollution, deforestation and land desertification. Dust and dust are roughly the same.

Question 9: The main causes of sandstorms "Rich dust sources, strong winds and extremely unstable atmosphere are three indispensable factors that cause sandstorms. The latter two are mainly related to meteorological conditions, while the former is related to land desertification. Therefore, although land desertification is not the main factor causing sandstorms and their changes, it is an important factor, so we must never ignore the control of land desertification. " ?

Haha, does Qian Zhengan, a sandstorm expert, sometimes make mistakes? ! !

Sandstorm, no doubt, is caused by desertification of the land! ! There is an absurd saying that "land desertification is not the main factor causing sandstorms and their changes"! !

Can you still blame the airflow? The shortage in New Zealand is extremely high. Air flow is a natural phenomenon. Land desertification is man-made. It is caused by our current wrong practices: grassland desertification and land desertification. The past: the wind blows and grass sees cattle and sheep, and now quicksand is everywhere. A mistake is a mistake. Don't hide it. If it is not changed, it will bring irreparable disaster to future generations.

I can see the level of "expert" now.

120 Respondent: cfzpfei- 9th grade Jinshi.

Question 10: The main cause of sandstorm formation is a disastrous weather phenomenon in which wind and sand interact. Its formation is closely related to global greenhouse effect, El Nino phenomenon, sharp decline of forests, vegetation destruction, species extinction, climate anomalies and other factors. Among them, over-exploitation of natural ingot source, over-cutting of forest and over-reclamation of land caused by population expansion are the main reasons for frequent sandstorms.