【中文介绍】

       近年来，中国极端降水灾害频发，如2021年7月的河南郑州暴雨，10月的山西洪涝等，都对人类社会和生态环境产生了破坏性的影响，因而理解中国极端降水变化的成因对防灾减灾和气候变化应对措施的制定具有重要意义。大量研究证据表明，人为影响是全球极端降水变化的重要驱动因子。但是，人类活动对中国极端降水变化的影响认识仍非常有限。

      本研究基于最新的CMIP6多模式结果，探究了人类活动等不同外强迫因子对过去近50年（1961-2014年）中国极端降水变化的影响。利用最优指纹法，对不同外强迫下的总降水量 （PRCPTOT）、强降水日数（R10mm）、强降水量（R95p和R99p）、最大日降水量（RX1day）和连续五日最大降水量（RX5day）这六个典型的极端降水指数变化进行检测归因。结果指出，人类活动强迫下的中国极端降水变化与观测到的极端降水变化基本一致，整体呈增加趋势。在R95p、R99p、RX1day和RX5day的变化中可以检测到人类活动信号，并且能够成功地与自然外强迫信号分离。此外，温室气体信号在R95p、R99p和RX1day的变化中也可以被单独检测到，但只有在R99p和RX1day的变化中温室气体强迫能够与自然外强迫和其他人类活动强迫的影响分离，在RX5day的变化中可以与自然外强迫和人为气溶胶强迫的影响分离。因此，中国极端降水的增强能够归因于人类活动的影响，其中温室气体起主导作用。但是，在PRCPTOT和R10mm的变化中并未检测到人类活动信号。此外，尽管人为气溶胶信号目前无法被检测，但它会部分抵消温室气体在中国极端降水变化中的作用。

  【英文介绍】

  Precipitation extremes have exerted devastating effects on the ecosystems, environments, and human society in China. Understanding the causes of changes in precipitation extremes over China is thus critical for the policy-makers and the general public. However, evidence of human influence on precipitation extremes over China is less robust, and more efforts are urgently needed for detection and attribution studies on extreme precipitation events over China. This study explored the human influence on the observed changes in precipitation extremes across China for the period of 1961–2014 by the latest simulations from the Coupled Model Intercomparison Project Phase 6 (CMIP6). Changes in observations and CMIP6 simulations under different external forcings for annual total wet-day precipitation (PRCPTOT), the number of heavy precipitation days (R10mm), very wet days (R95p), extremely wet days (R99p), the maximum 1-day precipitation amount (RX1day), and the maximum 5-day precipitation amount (RX5day) are compared using a regularized optimal fingerprinting method. The results show that both anthropogenic (ANT) and greenhouse gas (GHG) experiments generally exhibit increasing trends in precipitation extremes over China, agreeing with the overall observed increases. The ANT influence is robustly detected for R95p, R99p, RX1day, and RX5day over China, with clear separation from the natural forcing. Additionally, the GHG signal is also detectable for R95p, R99p, and RX1day but separated from the natural and other ANT forcings for only R99p and RX1day, and from the natural and ANT aerosol forcings for only RX5day. Thus, the intensified precipitation extremes can be attributed to human influence dominated by the GHG effect. However, detections fail for PRCPTOT and R10mm. The ANT aerosol forcing may partly offset the role of the GHG responses to observed increases despite being undetectable.

  【关键图表】

  【引用格式】       

  Xu HW, Chen HP and Wang HJ. 2022. Detectable Human Influence on Changes in Precipitation Extremes across China. Earth’s Future, 10, e2021EF002409.