新安江流域气象干旱和水文干旱特征及两者之间的关系研究

Study on the characteristics of meteorological and hydrological droughts in Xin’an River Basin and their relationship

新安江流域是传统丰水区,对该区域进行干旱演变规律以及气象-水文干旱传播特征及其响应关系的研究,对于流域水资源的调度和管理具有重要科学意义。基于新安江流域近63 a的降水和径流数据,利用标准化降水指数(Standardized Precipitation Index,SPI)和标准化径流指数(Standardized Runoff Index,SRI),研究不同时间尺度的新安江气象干旱和水文干旱的演变规律,并分析流域水文干旱对气象干旱的时滞效应。结果表明:(1)1960—2022年新安江流域的气象干旱和水文干旱主要发生在20世纪60年代、70年代末到80年代中期以及21世纪初,2010年至今新安江整体处于水资源丰盈状态,其余时段则干旱与湿润交替发生。(2)近63 a的数据显示,新安江流域总体呈现变湿趋势,干旱事件有所减少。其中冬季和夏季变湿最为明显,且水文角度变湿趋势比气象角度更为明显。(3)新安江流域的水文干旱与气象干旱显著相关,通常在气象干旱发生后1~3个月出现。水文干旱对气象干旱在汛期的相关性和响应速度均高于非汛期。因此,应更加关注汛期的流域干旱并采取针对性措施。

Xin’an River Basin is a typical water-abundant area.Characteristics exploration of the drought events and study on the re⁃sponse of hydrological drought to meteorological drought in Xin’an River Basin largely benefits the scientific reference for basin water management.This study calculated the Standardized Precipitation Index(SPI)and Standardized Runoff Index(SRI)with the monthly data of inflow runoff and precipitation from 1960 to 2022 in Xin’an River Basin.Based on SPI and SRI,the evolution of meteorological and hydrological droughts under different time scales and the seasonal response of hydrological drought to meteorological drought were analyzed.The results are as follows:(1)From 1960 to 2022,meteorological and hydrological droughts in the Xin’an River Basin mainly occurred in the 1960s,late 1970s to mid-1980s and early 2000s.Meteorological and hydrological droughts have rarely occurred since the 21st century;dry and wet alternated frequently over the remaining periods of time.(2)Mann-Kendall trend test results show a wet⁃ting trend during the past 63 years,and the effects of drought have mitigated.While in winter and summer,it showed drought decreas⁃ing trend in the basin.The hydrological trend of becoming wet was more obvious than that of meteorological.(3)The correlation be⁃tween hydrological drought and meteorological drought in Xin’an River is high.Also,the hydrological drought lags behind the meteoro⁃logical drought for 1-3 months.The seasonal response of hydrological drought to meteorological drought in flood season shows higher correlation and faster speed than that in dry season.Because of the quick response of hydrological drought to meteorological drought in flood season,more focus and targeted steps should be taken on the drought state of the basin in the flood season.