Abstract:

The middle reaches of Yarlung Zangbo River are the most serious area of dust disaster on the Tibetan Plateau. Using the hourly minimum visibility data of 15 meteorological stations in the middle reaches of the Yarlung Zangbo River from October to April in 2017-2020， a dust transmission matrix was constructed based on the transfer entropy method to study the diurnal variation characteristics and spatial interaction effects of dust weather. The results show that the dust weather mainly occurs in the two wide valley sand source areas of Shannan and Shigaze， with 3-4 h duration and a spatial difference between the single-peak structure with the peak during the day in the south of the Yarlung Zangbo River and the double-peak structure with the peak in the first half of the night in the north. The transfer entropy method can objectively and quantitatively describe the spatial structure of dust weather transmission in the region. Dust has cross-administrative region transmission in space， also influences each other in the region， forming complex spatial interaction influence. The spatial difference of regional transmission is mainly affected by site geography， dust source layout， wind direction and wind speed， the two wide valley and north high altitude area not only significantly affects the site's own and intra-regional transmission contributions， but also contributed very strong outside dust transmission under the action of westerlies. The two wide valleys and high altitude area are not only important nodes in the dust transmission space network， but also key areas of dust control.

Key words: dust, Yarlung Zangbo River, diurnal variation, transfer entropy, spatial transmission