2022年鄱阳湖流域干旱综合评估及成因分析

Comprehensive evaluation and cause analysis of drought in Poyang Lake Basin in 2022

2022年鄱阳湖流域发生了极端的干旱事件,综合评估其干旱程度对于探究流域旱情变化规律、开展抗旱保供水工作具有重要意义。基于鄱阳湖“五河”和湖区1960~2022年逐月降水、径流数据,采用标准化降水指数(SPI)和标准化径流指数(SRI)指标评估鄱阳湖各分区干旱程度,分析了干旱时空演变特征,结合大气环流指数初探了旱情成因。结果表明:2022年7~10月鄱阳湖流域降水和径流相比历史同期明显减少,不同分区累计降水量偏少63%~78%、径流量偏少29%~70%;2022年7~10月鄱阳湖流域气象干旱和水文干旱程度均较高,且表现为全流域干旱;从8月起绝大部分区域表现为中旱以上,部分区域表现为重旱和特旱。根据大气环流资料分析,在2020~2021年La Nina事件影响下,2022年夏秋季西太平洋副热带高压偏北,致使流域内降水偏少、高温频发,发生持续高温干旱事件,出现“汛期反枯”现象。研究成果可为鄱阳湖流域抗旱保水工作提供技术支撑。

An extreme drought event occurred in Poyang Lake Basin in 2022.Comprehensive evaluation of its drought degree is of great significance to exploring the change rule of the drought events in Poyang Lake Basin and carrying out the work of drought fighting and water supply.Based on the monthly precipitation and runoff data of the Five Rivers and the lake area of Poyang Lake from 1960 to 2022,the standardized precipitation index(SPI)and the standardized runoff index(SRI)were used to evaluate the drought degree in each region of Poyang Lake.The spatial-temporal evolution characteristics of drought were analyzed,and the causes of drought were discussed in combination with the atmospheric circulation index.The results showed that the precipitation and runoff in Poyang Lake Basin decreased significantly from July to October 2022 compared with those in the same period of history.The accumulative precipitation and runoff in different regions were 63%~78%less and 29%~70%less,respectively.The degrees of meteorological drought and hydrological drought in Poyang Lake Basin were high from July to October in 2022,manifesting as a whole basin drought.From August,most of the regions showed moderate drought and above,and some regions showed severe drought and extreme drought.According to the analysis of atmospheric circulation data,under the influence of La Nina event from 2020 to 2021,the Western Pacific subtropical high moved northward in summer and autumn of 2022,resulting in less precipitation and frequent high temperature in the basin,continuous high temperature and drought events,and the phenomenon of‘drought in flood season’happened.The research results can provide technical support for drought fighting and water conservation in Poyang Lake Basin.