Transport of dust from Gobi Desert to the Tibetan Plateau and its dynamic mechanism:a case study of a dust event in April of 2020
The Gobi Desert is a region known for its frequent sandstorms,and is one of the key sources of sand-storms in East Asia.The Tibet Plateau is adjacent to the two major sand source regions of East Asia and South Asia,and is one of the most sensitive regions to climate change in the world.However,the transmission path and mechanism of the Gobi Desert dust to the Tibet Plateau are still unclear.Based on the regional air quality mode WRF-Chem,FNL reanalysis data and the HYSPLIT backward trajectory model,a strong dust event in April of 2020 was used to explore the dust transmission path and transmission mechanism from the Gobi Desert to the Tibet Plateau.The results showed that during this dust event,the east and north slopes of the Tibet Plateau were important channels for dust transmission from the Gobi Desert to the Tibet Plateau.Affected by the circula-tion situation and the high terrain,the dust transmission efficiency on the north slope of the Tibet Plateau is great-er than that on the east slope,while the vertical movement of dust on the east slope is stronger than that on the north slope.The 500 hPa cyclone system east of the Ural Mountains and the Mongolian cyclone jointly control the middle and high latitudes and affect the dust transport process.With the eastward movement of the mid-high latitude cyclone systems,the 500 hPa Xinjiang ridge was destroyed,and the short-wave trough over the Tibet Plateau began to be established.The low layer convergent circulation in front of the short-wave trough is condu-cive to the maintenance of the 700 hPa closed low pressure,which promotes the northerly wind on the northern slope of the Tibet Plateau,and is conducive to the transport of dust from the northern slope to the plateau.The downward transmission of the 200 hPa upper-level jet stream caused the near-ground easterly wind to prevail in the Hexi Corridor,which was conducive to the transport of the Gobi Desert dust to the plateau.This circulation situation constitutes a favorable wind field for dust transmission from the Gobi Desert from the eastern slope to the Tibet Plateau.The research results further improve the transmission path of the Gobi Desert dust,and provide scientific support for the study of the weather and climate change of the dust influence on the Qinghai-Tibet Pla-teau and its surrounding areas.
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