首页|Multiscale causes of the 2022 Yangtze mega-flash drought under climate change

Multiscale causes of the 2022 Yangtze mega-flash drought under climate change

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The 2022 Yangtze mega-flash drought is characterized by strong intensity and rapid development both in time and space,accompanied by a persistent anticyclonic circulation anomaly.However,the causes of the extreme event remain elusive given the multiscale nature of drought.Here we presented a brief overview for the oceanic and terrestrial causes of the mega-flash drought during the summer of 2022,and estimated the risk in a changing climate.Using the soil moisture percentile as the drought index,it was found that the drought expanded to the entire Yangtze River basin within two months,with 80%of basin under severe drought conditions at the end of August.Both the intensity and onset speed of the 2022 mega-flash drought were ranked as the first during the past 62 years,with return periods of 86 and 259 years,respectively.The results of composite analysis showed that the spring La Niña can facilitate the abrupt change from a wet/normal condition in May-June to drought in July-August over the Yangtze River basin,which was beneficial for the increase of flash drought intensity and onset speed in 2022.The analysis through the linear regression also indicated that the unprecedented intensity was associated with the negative phase of the Pacific Decadal Oscillation.Quantified by a coupling strength index for soil moisture and vapor pressure deficit,it was found that there was a strong land-atmosphere coupling over the Yangtze River basin during July-August 2022.The attribution by using CMIP6 climate models suggested that land-atmosphere coupling increased the risks of flash drought intensity and onset speed like 2022 by 61%±6%and 64%±7%under natural climate forcings,and the synergy of coupling and anthropogenic climate change would increase the risks by 75%±22%and 85%±12%.Our findings emphasized the role of land-atmosphere coupling combined with anthropogenic climate change in intensifying flash droughts.

Flash droughtYangtze River basinLand-atmosphere couplingClimate changeAttribution

Xing YUAN、Yumiao WANG、Shiyu ZHOU、Hua LI、Chenyuan LI

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School of Hydrology and Water Resources,Nanjing University of Information Science and Technology,Nanjing 210044,China

Institute of Atmospheric Physics,Chinese Academy of Sciences,Beijing 100029,China

Key Laboratory of Hydrometeorological Disaster Mechanism and Warning of Ministry of Water Resources,Nanjing University of Information Science and Technology,Nanjing 210044,China

National Natural Science Foundation of ChinaNatural Science Foundation of Jiangsu Province for Distinguished Young Scholars

42330604BK20211540

2024

中国科学:地球科学(英文版)
中国科学院

中国科学:地球科学(英文版)

影响因子:1.002
ISSN:1674-7313
年,卷(期):2024.67(8)