Advances in Earth Science ›› 2022, Vol. 37 ›› Issue (9): 925-936. doi: 10.11867/j.issn.1001-8166.2022.052

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Analysis of the Vertical Momentum Transmission Characteristics of Different Intensity Trough Type Sandstorm Along the Hexi Corridor, China

Chunyan ZHANG 1 , 2( ), Yanying LI 1 , 2( ), Xingwei MA 1, Xiaojing LI 1, Xin NIE 2   

  1. 1.Wuwei Meteorological Bureau, Wuwei Gansu 733000, China
    2.Key Laboratory of Arid Climatic Change and Reducing Disaster of Gansu Province/Key Open Laboratory of Arid Climatic Change and Disaster Reduction of China Meteorological Administration/Institute of Arid Meteorology, China Meteorological Administration, Lanzhou 730020, China
  • Received:2022-01-20 Revised:2022-07-24 Online:2022-09-10 Published:2022-09-28
  • Contact: Yanying LI E-mail:1325086269@qq.com;lyyqxj@163.com
  • About author:ZHANG Chunyan (1990-), female, Baiyin City, Gansu Province, Engineer. Research areas include weather forecast and research. E-mail: 1325086269@qq.com
  • Supported by:
    the National Natural Science Foundation of China “Influence mechanism of momentum downward propagation from upper atmosphere to boundary layer on strong sandstorms over Hexi area”(41975015)

Chunyan ZHANG, Yanying LI, Xingwei MA, Xiaojing LI, Xin NIE. Analysis of the Vertical Momentum Transmission Characteristics of Different Intensity Trough Type Sandstorm Along the Hexi Corridor, China[J]. Advances in Earth Science, 2022, 37(9): 925-936.

Hourly surface meteorological observation data from 13 weather stations along the Hexi Corridor, China, and MICAPS high- and low-air data were used to analyze the vertical structure characteristics of trough-type strong sandstorm weather over the Hexi Corridor on April 24~25, 2010, April 23~24, 2014, and April 4, 2018. The results show that the polar front jet at 300 hPa is the main upper air dynamic system causing trough sandstorms in the Hexi Corridor area. Gale sandstorms appear near the upper-air westerly jet (≥32 m/s), hollow jet (≥20 m/s), and low-level jet (≥12 m/s). In the early stages of a sandstorm, the surface layer air is dry and hot. Then, the cold air invades, resulting in a violent exchange between the cold and warm air, which leads to the formation of an unstable layer junction in the boundary layer. The cold air sinks after the high trough (the central strength of cold current less than or equal to -10×10-5 K/s), which rapidly transfers the strong wind down to the ground and generates strong winds. The upper-level jet in front of the trough strengthens the vertical dynamic pumping, and the deep convergence and divergence zones and the surface cold front enhance the upward movement. The maximum upward velocity was observed at 500 hPa and its intensity was less than or equal to -30×10-5 Pa/s. The closer the sandstorm is to the center of the jet stream axis, the greater the difference in convergence and divergence centers. The closer the vertical distance, the lower the convergence center position, the thicker the convectional unstable stratification, the lower the height, the stronger the intensity of the cold advection center, and the rising speed area reaches a maximum. The nearer the cold advection is to the center distance, the stronger the sandstorm and the longer the duration. The wider the center, the more the 300 hPa upper-level jet axis controls the Hexi corridor area and the wider the sandstorm appears.

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