What's the dusty weather like in Beijing?

In recent years, sandstorms in Beijing are mostly floating dust, and the intensity of rare sandstorms is also weak. For example, the strongest sandstorm occurred on April 6, 2000, with the maximum wind speed 14m/s and the minimum visibility of 500m, was generally weak.

According to statistics, from 197 1 to 1998, there were 355 times of sand blowing, 25 times of floating dust 1 1, and 25 times of sandstorm, accounting for 74%, 2 1% and 5% respectively. After liberation, the dusty weather in Beijing decreased year by year from the 1950s to the early 1990s, and so did the windy 1970s, with the phenomenon of "windy without sand". However, since 1998, the sandstorm weather has obviously picked up, with 0/2 times in 2000, 0/8 times in 2006, 0/3 times in 2002 and 0/8 times in 2006. Close to the level of the 1960s (1995 12 times, 1966 20 times).

According to the statistical data of dust weather in various counties, the dust weather in Beijing is divided into five types: sand blowing, floating dust, sand blowing-floating dust, strong wind-floating dust and sandstorm. Type differentiation is closely related to the geographical location of the station. According to the types of sandstorm weather at each station, the results of geochemical and heavy mineral analysis and the meteorological nephogram of typical sandstorm weather process, it is considered that the source of sandstorm is sand blowing in situ, and the ancient sediment deposition of Yongding, Chaobai River and Yuqi River and the abandoned soil of urban buildings are the main sources of sandstorm. Sandstorm and floating dust mainly come from the upwind sandstorm-prone areas, and dry farmland and degraded grassland in the farming-pastoral ecotone on the northern slope of Yinshan Mountain in Inner Mongolia Plateau and the southern edge of Hunshandake Sandy Land are the main providers of dust.

Restricted by geographical location and topography, there are three main channels for headwind dust to enter Beijing, commonly known as "tuyere". They are the valleys of Guan Gou, Chaobai River and Yongding River.

Historically, Beijing had a strong sandstorm. The earliest record of sandstorm appeared in 440 AD (the first year of Taiping Zhenjun in the Northern Wei Dynasty), and the sandstorm occurred most frequently and intensively in Beijing Plain from the middle of15th century to the middle and late of17th century (from the middle and late Ming Dynasty to the early Qing Dynasty). In addition, sandstorms and persistent drought accelerated the demise of the Ming Dynasty.

Two conclusions can be drawn from the development history of sandstorms in Beijing:

(1) The sandstorm in Beijing only appeared several years (about 40 years) after the surrounding land was extensively reclaimed. (2) Sandstorms are most rampant in dry and cold climates.