Analysis of drought characteristics and comparison of historical typical years with 2022 drought in the Yangtze River Basin

In 2022, the Yangtze River Basin (YRB) experienced an unprecedented drought with long-term, large-scale, and severe consequences for agriculture, ecology, industrial production, and economic life. In order to investigate the evolution characteristics of the drought event in 2022, and discuss the similarities and differences with its similar historical drought years, this study focused on droughts during July-October (summer and autumn). The Standardized Precipitation Evapotranspiration Index was employed as a drought indicator. To analyze the spatial and temporal distribution patterns of drought and its mutability and periodicity in the YRB during 1951-2022, this study utilized the Empirical Orthogonal Function (EOF), Pettitt test, and wavelet analysis methods. We obtained similar drought years with the 2022 drought spatial pattern using the clustering method. The results show that the drought in the YRB in 2022 mainly presented a "basin-wide" drought spatial distribution pattern based on the first mode of EOF. The main periodicity of the "basin-wide" drought spatial distribution pattern was about 50 years. The July drought distribution patterns in 1952, 1953, and 2006 were most similar to that in 2022; however, the drought evolution patterns were obviously different after August. In comparison, the YRB experienced the largest drought-impacted area in 2022, and the impacted area proportions of severe and extreme drought increased at the fastest speed.