Recent decreasing precipitation and snowmelt reduce the floods around the Chinese Tianshan Mountains

• Published in: The Science of the total environment 2023-12, Vol.905, p.167324-167324, Article 167324
• Main Authors: Li, Xiang, Cui, Peng, Zhang, Xueqin, Hao, Jiansheng, Li, Chaoyue, Du, Xinguan
• Format: Article
• Language: English
• Subjects: CMIP 6; Flood; Rainstorm; Snowmelt; Tianshan Mountains; Warming hiatus; Water vapor transport
• ISSN: 0048-9697; 1879-1026
• DOI: 10.1016/j.scitotenv.2023.167324

Understanding and managing mountain floods has become increasingly urgent, with global climate change and human activities exacerbating flood risk. However, flood research in Tianshan Mountains, a typical flood-prone mountainous region in China, is still insufficient. Here, we customized a set of flood research methods based on rainstorms and extreme snowmelt events, including a new flood counting method that comprehensively considered the frequency and magnitude of floods and the methods of flood classification and change attribution. We found that floods around the Chinese Tianshan Mountains (CTM) increased from 2014 to 2016 but decreased rapidly from 2016 to 2021, with storm floods, snowmelt floods, and mixed floods accounting for 38.3 %, 26.5 %, and 34.6 % of total flood events, respectively. The variation of floods was most significantly correlated with the average and extreme precipitation, followed by the temperature-driven average snowmelt change. Furthermore, atmospheric circulation anomalies and water vapor input from the western boundary of CTM caused decreasing precipitation and storm floods. Meanwhile, the warming hiatus also greatly impacted declining flood frequency. Notably, flood frequency is projected to rebound soon because of the rising precipitation and temperature, infrastructure aging, and reservoir abandonment, implying the present flood decline unsustainable. Our research develops a strategy to investigate short-term flood anomalies under climate oscillations around the CTM, providing insights into flood research and prevention in global mountainous regions. [Display omitted] •Customized methods of flood counting and classification in CTM•Floods declined rapidly from 2016 to 2021 around CTM•Storm floods decreased due to circulation anomalies and water vapor change•Snowmelt flood decrease was related to the warming hiatus since 2016•The flood frequency is projected to rebound