Long-term trend of water vapor over the Tibetan Plateau in boreal summer under global warming

This study is led by Yihui Ding，Qingquan Li (National Climate Center, China Meteorological Administration), Jingwen Yu，Jie Zhang, Xinyong Shen and Qingyuan Wu (Nanjing University of Information Science & Technology)，which is recently published in the Science China Earth Sciences. The team analyzes the long-term trend of summer water vapor and its mechanism over the Tibetan Plateau in boreal summer under global warming, and also projects the future changes in water vapor and precipitation over the Tibetan Plateau.

This study indicates that the water vapor content and the net water vapor budget over the Tibetan Plateau show notable increasing trends, which are mainly manifested by a significant increase in the net water vapor import over the Tibetan Plateau and a significant decrease in the water vapor export on the eastern boundary of the Tibetan Plateau. This is mainly due to an anomalous anticyclone from Lake Baikal to the Mongolian Plateau.

The team investigates the CMIP6 models’ ability in simulating the variation characteristics of water vapor transport, water vapor content and precipitation over the Tibetan Plateau. The results indicate that compared with reanalysis data, multi-model ensemble mean can well capture the distributions of these variables. The models’ outputs are further used to project future changes in water vapor and precipitation over the Tibetan Plateau. The projection results indicate that by the end of the twenty-first century, the water vapor content, the net water vapor import and precipitation over the Tibetan Plateau will increase. Under a high-emissions scenario and compared with the current period (1991–2014), these three variables will increase by 47.99%, 59.77% and 18.59% in the long term (2081–2100), respectively. The significant enhancement of meridional water vapor transport over the northern Tibetan Plateau may be the main reason for the increase in humidity over the Tibetan Plateau.

In contrast to previous studies, this study finely delineates the boundary of the Tibetan Plateau and investigates the water vapor budget and its long-term trend at different altitude levels of the Tibetan Plateau, which is helpful to understand the water vapor transport structure of the ‘Asian water tower’ and its future variation. This study also quantitatively analyzes the future changes in water vapor (including the water vapor budget at various boundaries, precipitation, and so on) due to global warming, and determines the future variation trends and spatial distribution characteristics of the water vapor content and water vapor transport over the Tibetan Plateau under different emission scenarios. This study contributes to the understanding of the future variation of water vapor over the Tibetan Plateau as the ‘Asian water tower’, and also provides a reference for projecting future changes in water vapor over the Tibetan Plateau.

This work was jointly supported by the Second Tibetan Plateau Scientific Expedition and Research of China (Grant No.2019QZKK0208), the Strategic Priority Research Program of the Chinese Academy of Sciences (Grant No. XDA20100304), and the National Natural Science Foundation of China (Grant No. 41790471), etc.

See the article:

Yu J, Li Q, Ding Y, Zhang J, Wu Q, Shen X. 2022. Long-term trend of water vapor over the Tibetan Plateau in boreal summer under global warming. Science China Earth Sciences, https://doi.org/10.1007/s11430-021-9874-0

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