Spatio-temporal variation of precipitation in the Yarlung Zangbo river basin [雅鲁藏布江流域降水时空变化特征]

作者：Zhang Y.; Liu C.; Liang K.; Lyu J.

来源：Acta Geographica Sinica, 2022, 77(3): 603-618.

DOI：10.11821/dlxb202203008

• Atmospheric circulation factor
• Extreme precipitation
• Qinghai-Tibet Plateau
• Spatio-temporal variation
• Water resources region
• Yarlung Zangbo river

The Yarlung Zangbo river basin (YZRB) is sensitive to global climate change. The precipitation changes in the YZRB have a great impact on the evolutions of water system, ecosystem and mountain disaster system on the Qinghai-Tibet Plateau. In this study, we divided three water resources regions of the YZRB into nine subregions through hydrological analysis. Based on precipitation data within the YZRB from 1979 to 2018, we examined the spatio-temporal variations of precipitation at annual, wet and dry seasons, monthly scales, daily and hourly extreme precipitation in the study area and its nine subregions. We further discussed the correlation between precipitation and typical large-scale atmospheric circulation factors. The results showed that: (1) From 1979 to 2018, at the whole basin scale, precipitation at each time scale showed an overall upward trend. Among them, annual precipitation showed the largest increasing trend of 2.5 mm?a-1. Annual precipitation, dry and wet precipitation, and typical hourly scale extreme precipitation (Rx3hour and Rx12hour) increased significantly at the 95% confidence level. At the regional scale, the variation trend of precipitation at different time scales in each subregion showed more obvious inconsistencies. Except for the increasing trend of hourly scale extreme precipitation, the trends of precipitation in all the subregions were different. (2) There was an obvious spatial heterogeneity of precipitation in the YZRB, and the spatial heterogeneity of precipitation did increase with the shortening of the precipitation time scale. The precipitation at each time scale showed a gradual decreasing trend from the east to the west. The southeastern part of the YZRB (i.e. subregion Ⅲ-2) had been the center of high value, and the central and western parts (i.e. subregions Ⅰ-2 and Ⅱ-1) had a regional high value center. (3) The Northern Hemisphere Subtropical High (NHSH) and the Northern Hemisphere Polar Vortex (NHPV) had significant effects on precipitation changes. The results can help us to understand the characteristics of local precipitation at multiple scales, and provide a scientific basis for water cycle research, water resources development and utilization, and prevention of flash flood disasters in the YZRB and the Qinghai-Tibet Plateau.

• 单位
  中国科学院; 中国科学院大学