Assessing the Performance of CMIP6 Models in Simulating Droughts across Global Drylands  

作　　者：Xiaojing YU Lixia ZHANG Tianjun ZHOU Jianghua ZHENG 

机构地区：[1]LASG,Institute of Atmospheric Physics,Chinese Academy of Sciences,Beijing 100029,China [2]Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters,Nanjing University of Information Science&Technology,Nanjing 210044,China [3]University of Chinese Academy of Sciences,Beijing 100049,China [4]College of Geography&Remote Sensing Sciences,Xinjiang University,Urumqi 830046,China

出　　处：《Advances in Atmospheric Sciences》2024年第2期193-208,共16页大气科学进展（英文版）

基　　金：supported by Ministry of Science and Technology of China (Grant No. 2018YFA0606501);National Natural Science Foundation of China (Grant No. 42075037);Key Laboratory Open Research Program of Xinjiang Science and Technology Department (Grant No. 2022D04009);the National Key Scientific and Technological Infrastructure project “Earth System Numerical Simulation Facility” (EarthLab)。

摘　　要：Both the attribution of historical change and future projections of droughts rely heavily on climate modeling. However,reasonable drought simulations have remained a challenge, and the related performances of the current state-of-the-art Coupled Model Intercomparison Project phase 6(CMIP6) models remain unknown. Here, both the strengths and weaknesses of CMIP6 models in simulating droughts and corresponding hydrothermal conditions in drylands are assessed.While the general patterns of simulated meteorological elements in drylands resemble the observations, the annual precipitation is overestimated by ~33%(with a model spread of 2.3%–77.2%), along with an underestimation of potential evapotranspiration(PET) by ~32%(17.5%–47.2%). The water deficit condition, measured by the difference between precipitation and PET, is 50%(29.1%–71.7%) weaker than observations. The CMIP6 models show weaknesses in capturing the climate mean drought characteristics in drylands, particularly with the occurrence and duration largely underestimated in the hyperarid Afro-Asian areas. Nonetheless, the drought-associated meteorological anomalies, including reduced precipitation, warmer temperatures, higher evaporative demand, and increased water deficit conditions, are reasonably reproduced. The simulated magnitude of precipitation(water deficit) associated with dryland droughts is overestimated by 28%(24%) compared to observations. The observed increasing trends in drought fractional area,occurrence, and corresponding meteorological anomalies during 1980–2014 are reasonably reproduced. Still, the increase in drought characteristics, associated precipitation and water deficit are obviously underestimated after the late 1990s,especially for mild and moderate droughts, indicative of a weaker response of dryland drought changes to global warming in CMIP6 models. Our results suggest that it is imperative to employ bias correction approaches in drought-related studies over drylands by using CMIP6 outputs.

关 键 词：DROUGHTS hydrothermal conditions DRYLANDS CMIP6 model evaluation 

分 类 号：P426.616[天文地球—大气科学及气象学]