为了掌握江苏里下河地区水循环与生态系统特征,根据里下河腹部地区1961—2018年降水、径流资料,运用累积距平、相关性分析、Mann-Kendall检验、滑动T检验以及Morlet小波分析等方法,揭示径流系数多年的演变趋势和变化规律。结果表明:①径流系数随着降水量丰枯而变化,且与降水量主、次周期基本一致,但年内、年际不均匀程度比降水量大得多;径流系数年内变化不仅与降水量年内分配特点有关,还与区域地理环境、农业生产等密切相关。②径流系数在1966年、1982年发生突变,而降水量未发生突变;在随降水量丰枯变化过程中,20世纪80年代径流系数相对降水量增幅最大,2012年后增幅最小;径流系数在不同时期的变化,反映了水循环和自然生态系统调节平衡能力的改变。该研究对该地区防汛抗旱和水资源利用与管理具有重要的现实意义。

In the hope of understanding the water cycle and ecosystem features of Lixia River in Jiangsu Province, we examined the trend and variation regularities of runoff coefficient over years (1961-2018) based on precipitation and runoff data via accumulated anomaly analysis, correlation analysis, Mann-Kendall test, moving-t test, as well as Morlet wavelet analysis. Results revealed that: 1) Runoff coefficient changed with precipitation, and the change was consistent with primary and secondary cycles; but the unevenness of annual and interannual runoff is much greater than that of precipitation. The annual variation of runoff coefficient is not only related to the annual distribution of precipitation, but also closely related to regional geomorphological characteristics and agricultural production. 2) In recent years, precipitation has not increased significantly, while runoff coefficient changed abruptly in 1966 and 1982. In the process of changing with precipitation, runoff coefficient increased the most in 1980s, and the smallest after 2012. The change of runoff coefficient in different periods reflects the change of water cycle and the adjustment and balance ability of natural ecosystem. The research findings are of practical significance for regional flood control and drought relief as well as the development and utilization of water resources.