How is the sandstorm that covers the sun caused?

Sandstorm is a general term for sandstorm and sandstorm. It refers to a severe sandstorm weather phenomenon in which strong winds blow a large amount of sand and dust substances into the air, making the air particularly turbid and the horizontal visibility less than 1 km. Among them, sandstorm refers to a sand-laden storm formed by strong winds blowing a large number of sand near the ground; Sandstorm is a storm formed by strong winds, which brings a lot of dust and other particles into the sky.

Sandstorm strikes

Sandstorm weather mainly occurs in late spring and early summer. This is because there is little precipitation in winter and spring in arid areas, the surface is unusually dry and loose, and the wind erosion resistance is very weak. When there is a strong wind blowing, a lot of dust will be involved in the air, forming sandstorm weather.

Globally, sandstorms mostly occur in inland desert areas, mainly the Sahara desert in Africa, and the midwest of North America and Australia are also one of the sources of sandstorms. From 1933 to 1937, the famous bowl-shaped sandstorm occurred in the midwest of North America due to severe drought. Asian sandstorm activity centers are mainly located in the Jordanian desert, Lower Mesopotamia between Baghdad and the northern coast of the Gulf, the southern Iranian coast near Abbas and the northern Afghan plain. Kazakhstan, Uzbekistan and Turkmenistan in Central Asia of the former Soviet Union are all affected areas with frequent sandstorms (≥ 15/ year), but their centers are on the sandy plain between Caspian Sea and Aral Sea and Amu Darya River.

Due to its unique geographical environment, the northwest of China is also a region where sandstorms frequently occur. The main source areas are Gurbantunggut Desert, Taklimakan Desert, Badain Jaran Desert, Tengger Desert, Wulanbuhe Desert and Mu Us Desert.

From 1999 to the spring of 2002, there were 53 sandstorms in China (1999, 2000 14, 2006 18 and 2002 12). Li Huang, deputy director of China Meteorological Bureau, announced his research results to the media. He said that in the spring of 2002, there were 12 sandstorms in northern China. It has three characteristics: concentrated occurrence period, strong occurrence intensity and wide influence range. The sources of dust weather affecting China can be divided into two types: overseas and domestic. The analysis shows that: 2/3 of the dusty weather originated in southern Mongolia, and it was strengthened by the supplement of dusty materials when passing through northern China; The sand source in China is only about 1/3. The dusty weather in Central Asia (Kazakhstan) is unlikely to affect the eastern part of Northwest China or even North China. The Taklimakan Desert in southern Xinjiang is a high incidence area of sandstorm weather in China, but it generally does not affect the eastern part of northwest China and North China. The path of sandstorm weather in China can be divided into northwest path, west path and north path: northwest path 1. Sandstorm weather generally originates in the central and western plateau of Mongolia or Alashan Plateau in western Inner Mongolia, and mainly affects northwest and north China. Northwest Route 2. Dust weather originated in southern Mongolia or central and western Inner Mongolia, mainly affecting the eastern part of northwest China, northern North China and most of northeast China; To the west, dusty weather originated in Gobi area in southwest or south Mongolia and desert area in western Inner Mongolia, mainly affecting northwest and north China. In the northerly route, dusty weather generally originates in the vast area south of Ulaanbaatar, Mongolia, and mainly affects the eastern part of northwest China, most of north China and southeast China.

Frequent sandstorms

According to statistics, there were eight sandstorms in China in the 1960s, namely 13 in the 1970s, 14 in the 1980s and more than 20 times in the 1990s, and the scope of sandstorms became wider and wider, resulting in heavy losses. The situation of several major gale and sandstorm weather in China since the 1990s is introduced as follows:1993: From April to early May, gale weather appeared many times in the north. 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, resulting in serious losses. 1994: From April 6, 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. 1 995:165438+1On 7 October, more than 40 counties (cities) in Shandong were hit by heavy rain, with 35 people killed, 12 1 missing, 320 injured and direct economic losses/kloc-0. 1996: On May 29th and 30th, 1965, the worst sandstorm swept the west of Hexi Corridor. The black wind suddenly broke out, the world was closed, the dust filled, the trees collapsed, and people had difficulty breathing. The direct economic loss in Jiuquan area, which suffered the most, reached more than 200 million yuan. 1998: On April 5, 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~ 10, and the instantaneous wind speed reaches 32 meters per second. The winds in other areas generally reach 6~7. Strong winds blew down trees and cut off power lines in some areas. 1999: From April 3rd to 4th, there were continuous strong winds and sandstorms 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. 2000: On March 22-23, there was a large-scale dusty weather 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. 2002: From March 18 to March/2 1 day, a sandstorm weather process with the largest scope, strongest intensity, the most serious impact and the longest duration since the 1990s, attacked China North1400,000 square kilometers and affected the population1300,000.