Understanding the Asian water tower requires a redesigned precipitation observation strategy

• 成果类型: Article
• 署名作者: Miao, Chiyuan; Immerzeel, Walter W.; Xu, Baiqing; Yang, Kun; Duan, Qingyun; Li, Xin
• 署名单位: Beijing Normal University; Utrecht University; Chinese Academy of Sciences; Institute of Tibetan Plateau Research, CAS; Tsinghua University; Hohai University
• 刊物名称: PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
• ISSN/ISSBN: 0027-13044
• DOI: 10.1073/pnas.2403557121
• 发表日期: 2024-06-04
• 关键词: temperature; gradients; basin

摘要

The Asian water tower (AWT) serves as the source of 10 major Asian river systems and supports the lives of - 2 billion people. Obtaining reliable precipitation data over the AWT is a prerequisite for understanding the water cycle within this pivotal region. Here, we quantitatively reveal that the observed precipitation over the AWT is considerably underestimated in view of observational evidence from three water cycle components, namely, evapotranspiration, runoff, and accumulated snow. We found that three paradoxes appear if the so - called observed precipitation is corrected, namely, actual evapotranspiration exceeding precipitation, unrealistically high runoff coefficients, and accumulated snow water equivalent exceeding contemporaneous precipitation. We then explain the cause of precipitation underestimation from instrumental error caused by wind - induced gauge undercatch and the representativeness error caused by sparse - uneven gauge density and the complexity of local surface conditions. These findings require us to rethink previous results concerning the water cycle, prompting the study to discuss potential solutions.