Causes of sandstorms in Northeast China

Question 1: The main reasons for the formation of sandstorms. "Abundant dust sources, strong winds and extremely unstable atmosphere are the three indispensable factors that cause sandstorms. The latter two are mainly related to meteorological conditions. 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, and we must not ignore the control of land desertification. "?

Haha, sandstorm expert Qian Zhengan also made mistakes sometimes? ! !

There is no doubt that the cause of sandstorms is desertification of the land! ! There is a ridiculous statement: "Although desertification of land is not the main factor causing sandstorms and their changes"! !

Can you still blame the air flow? Extremely desolate. Air movement is a phenomenon of nature. And land desertification is man-made. It is caused by our current wrong practices: grassland desertification and land desertification. In the past, cattle and sheep were seen in the windblown grass, now it has become quicksand everywhere. Mistakes are mistakes. Don't hide them. If you don't change, it will bring irreparable disaster to future generations.

It also shows the current level of “experts”.

120 Answers: cfzpfei - Jinshi 9th grade

Question 2: The main reason for the formation of sandstorms. Sandstorms are a disastrous weather phenomenon where wind and sand interact. It is inseparably related to factors such as the global greenhouse effect, El Ni?o phenomenon, forest decline, vegetation destruction, species extinction, and climate abnormalities. Among them, over-exploitation of natural sources, excessive deforestation, and over-cultivation of land caused by population expansion are the main reasons for frequent sandstorms.

Question 3: What is the main reason for the formation of sandstorms? "Abundant dust sources, strong winds and extremely unstable atmosphere are three indispensable factors that trigger 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 that causes sandstorms and their changes is a heavy deforestation factor, so we must not ignore the control of land desertification."?

Haha, sandstorm expert Qian Zhengan also made mistakes sometimes? ! !

There is no doubt that the cause of sandstorms is desertification of the land! ! There is a ridiculous statement: "Although desertification of land is not the main factor causing sandstorms and their changes"! !

Can you still blame the air flow? Extremely desolate. Air movement is a phenomenon of nature. And land desertification is man-made. It is caused by our current wrong practices: grassland desertification and land desertification. In the past, cattle and sheep were seen in the windblown grass, now it has become quicksand everywhere. Mistakes are mistakes. Don't hide them. If you don't change, it will bring irreparable disaster to future generations.

It also shows the current level of “experts”.

Question 4: The main cause of sandstorms Sandstorms are a weather phenomenon in which wind and sand interact. That is, strong winds blow up sand and dust on the ground, causing disastrous weather that sharply reduces atmospheric visibility. The causes are diverse, both natural and man-made, such as the global greenhouse effect, El Ni?o phenomenon, forest decline, vegetation destruction, species extinction, climate anomalies and other factors. Among them, over-exploitation of natural resources, excessive deforestation, and over-cultivation of land caused by population expansion are the main reasons for the formation of sand and dust storms, and have aggravated their intensity and frequency.

As a high-intensity sandstorm disaster, sandstorms do not occur in all windy places. Sandstorms are only likely to occur in areas with arid climate and sparse vegetation.

Sandstorms mostly occur from April to May every year. Taking northwest my country as an example, at this time of year, the Hawaiian high pressure forms in the Pacific, the Indian low pressure forms in the Asian continent, and strong southerly winds blow from the ocean. Toward the land, the Mongolian high pressure that controls the continent begins to move from west to north, where cold and warm air currents meet. The heavier Siberian cold current moves quickly from west to east, often forming strong winds. The wind force that forms sandstorms is generally above level 8, with a wind speed of about 25 meters per second. In addition, the formation of sandstorms requires sufficient sand sources, and sand and sand particles can be blown away from the ground by the wind. The northwest region of my country is located deep inland, with low forest coverage. Most of the land surface is desert and grassland, and there are many sandy wastelands, which provides conditions for the formation of sandstorms. Moreover, the poor people in the northwest also want to make a fortune by digging licorice, nostrils, and mining. These predatory and destructive behaviors have aggravated the sandstorm disaster in this region. *** The land is easily blown up by strong winds to form sandstorms or even strong sandstorms.

In a natural state, sandstorms are generally small in scale. However, due to people's indiscriminate cultivation of grassland and overgrazing, large areas of grassland have become wasteland, increasing the frequency and intensity of sandstorms. In the 1930s, during the development of the Great Plains in the west, the United States cut down forests and grasslands on a large scale, causing large areas of grassland to become desert, leading to the occurrence of three famous "black storms". It was estimated after a black storm that swept across the North American continent in 1934 that about 300 million tons of fertile soil was blown away at that time, of which 12.42 million tons of dust fell in Chicago in one day.

Sandstorms have many hazards: 1. Death of humans and animals, collapse of buildings, and reduction in agricultural production. Sandstorms are no less harmful to people, animals and buildings than typhoons and tornadoes.

On May 5, 1993, a huge sandstorm occurred in four northwest provinces of my country, resulting in 85 deaths, 31 missing, and direct losses of up to 540 million yuan. Beginning in the early morning of August 14, 1999, a moderate-intensity sandstorm occurred in Dunhuang and other areas in the Hexi Corridor of Gansu Province. The instantaneous wind speed reached 14 meters per second, and the visibility was between 200 and 300 meters. The sandstorm was like dusk. (Currently, there are still no casualties.) in statistics). In the past five years, my country's northwest region has been hit by sandstorms more than 20 times, causing economic losses of more than 1.2 billion yuan and more than 200 people dead and missing.

2. Air pollution and topsoil loss. There are at least 38 chemical elements in sandstorm dust. Its occurrence greatly increases the concentration of atmospheric solid pollutants, causing 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 crop yields.

The most important way to prevent sandstorms is to increase surface vegetation coverage. Specifically, it involves planting trees and grass and consolidating sediment. Since the founding of the People's Republic of China, my country has built the Three-North Shelter Forest connecting Northeast, North China and Northwest China, as well as planting trees and grass on the edge of the desert and other projects, which have played an important role in preventing and controlling the occurrence of sandstorms. According to statistics from Yulin City, located in northern Shaanxi Province, years of tree and grass planting have reduced sandstorms from 66 days per year in the 1950s to 5 days per year now.

Question 5: The main reason for the occurrence of sandstorms. There are three elements in the formation of sandstorms: strong wind, sand source and unstable air.

Strong wind

Strong enough and long-lasting wind is the driving force for the formation of sandstorms. For example, according to observations, when a strong sandstorm forms, if the wind speed reaches 30 meters per second (level 11 wind), then coarse sand (0.5~1.0 mm in diameter) will fly dozens of centimeters off the ground, and fine sand (0.125~0.25 mm in diameter) will fly Flying 2 meters high, powdery sand (diameter 0.05~0.005 mm) can reach a height of 1.5 kilometers, and clay particles (diameter less than 0.005 mm) can fly to a very high altitude.

Source of Sand

Our country is one of the countries with more deserts in the world. The northwest, North China and Northeast regions are places where deserts and sandy areas are concentrated in our country. The area of ??deserts and sandy areas here is as large as Covering more than 700,000 square kilometers, there are various types of sand dunes in the desert, which are divided into mobile sand dunes, semi-fixed sand dunes and fixed sand dunes according to their degree of stability. When sandstorms occur frequently, the amount of dust raised by mobile sand dunes is the largest, semi-fixed sand dunes are smaller, and fixed sand dunes are the smallest.

Except for deserts and sandy lands, most of northern my country belongs to mid-latitude arid and semi-arid areas. The ground is mostly sparse grassland and dry farmland, with sparse vegetation and human destruction. When the ground warms up and thaws in spring, On the ground surface, when strong winds arise, sand and dust spread, forming sand and dust weather locally and in areas where the strong winds pass.

Unstable air

Let us first look at an example in life. When you poke the stove, the fire is burning brightly. If you poke it gently, the ashes will often fly all over the house. When the fire is extinguished, dust will generally not rise if you exert greater force. This involves the issue of air stability. After the fire goes out, the temperature of the air above and below the stove is not much different, so the air is stable. When the fire is burning vigorously, the air near the stove is hot, and the air farther away from the stove is cooler. The hot air is lighter than the cold air and rises easily, so the air above the stove is unstable. In this way, the stirred ashes can easily rise with the hot air and then fly all over the house.

In nature, the same principle applies to sandstorms. If the air temperature at the lower level is lower and more stable, the sand and dust blown by the wind will not be carried very high; if the air at the lower level is If the temperature is high, it will be unstable and easy to move upward. When the wind blows, the sand and dust will be carried very high, forming a sandstorm. In fact, sandstorms in my country are generally strongest in the afternoon or afternoon to evening, because this is the time of day when the air is the most unstable.

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

my country’s satellite meteorologists systematically analyzed the six characteristics of sand and dust storms

According to the China National Satellite Meteorological Center, at the academic annual meeting held recently by the China National Satellite Meteorological Center, the National Satellite Meteorological Center Dong Chaohua, chief engineer and researcher of the center, researchers Fang Zongyi, Zheng Xinjiang, Lu Naimeng and Shao Yaping, a professor at the University of New South Wales in Australia, 17 people participated in the research on the Chinese sand and dust storm topic. Six major characteristics, numerical model forecasts and quantitative sand and dust studies were exchanged, providing a scientific basis for controlling sand and dust storms.

1. Time: Sandstorms in China mainly occur between March and April. Taking 2002 as an example, there were 12 sand and dust processes across the country, including 4 severe sand and dust storms, all of which occurred in March and April. The National Satellite Meteorological Center monitored and analyzed all the above processes.

2. Region: The main areas where sandstorms occur are between 110 degrees and 117 degrees east longitude and the vast area north of 38 degrees north latitude, that is, bounded by Cangzhou, Hebei Province, going north to Tianjin, Beijing, and Inner Mongolia, and going west longitude. Shijiazhuang, Yinchuan, Lanzhou, Qinghai Qilian, and north to the border of Inner Mongolia.

3. Source: The main source of sandstorms in China is Mongolia and even the desert areas of Central Asia. This type of sandstorm is intense and its impact is significantly greater than that of sandstorms in the domestic source areas; the source areas in my country are the Gansu Hexi Corridor and Inner Mongolia. South, northern Hebei and other desert areas.

4. Paths: There are four main paths of sandstorms that have affected Beijing in recent years, especially last spring: one is the Mongolia-Inner Mongolia-Beijing path turning to the northeast. The second is the path from which the Hexi Corridor moves eastward to Beijing. The third one affects Beijing from Zhurihe area in Inner Mongolia via Zhangjiakou area in Hebei Province. The fourth one affects the Beijing area from the northern Shanxi Plateau to the east.

5. Related factors: Through the main dust processes and related climatic factors in the Huahua area since 1998, especially in 2002... >>

Question 6: When renting a house in Beijing, you can learn about personal housing information through those methods. Rather than an intermediary? What issues do you need to pay attention to when renting a house? There is a Beijing section on the Sohu forum, and the top posts there are about renting. A lot of information very quickly, I found it in there, not too long ago.