近60年来长江入海水沙演变规律及影响因素分析

Driving Factors Analysis of the Evolution of Runoff and Sediment at Datong Station in Resent 60 Years

根据长江下游大通水文站长时间序列资料,运用累积曲线法、Mann-Kendall非参数检验法和小波分析等统计方法,揭示了长江入海水沙的演变规律及其影响因素。结果表明:①年径流量呈微弱减少趋势,而年输沙量显著下降,通过95%置信度检验;②径流量在1955年发生突变,输沙量在1997年发生突变;③小波分析表明径流量和输沙量分别存在23a和24a的周期性变化规律;④1971-1996年累积减沙量为22.13亿t,1997-2015年累积减沙量为44.44亿t;⑤年输沙量显著减少受降水影响不明显,主要是水库拦沙、河道采砂和水土保持等人为因素所致。

Based on long-time series data of the annual runoff and sediment at the key station along the lower reaches of Yangtze River, evolution characteristics and laws of annual runoff and sediment are revealed by means of Mann-Kendall and wavelet analysis, and its driving forces are analyzed.The results show that:① The amount of annual runoff shows a slightly decreasing trend and the amount of annual sediment shows an obviously decreasing trend.② The abrupt points of runoff occurred at 1955, and the amount of sediment changed in 1997.③ Wavelet analysis indicates periodicities of 23 years and 24 years for annual runoff and sediment processes, respectively.④ The cumulative sediment reduction was 22.13×108 t from 1971 to 1996, while the cumulative sediment reduction was 44.44×108 t from 1997 to 2015.⑤ The significant reduction of annual sediment transport was less affected by rainfall, which was mainly contributed from sand controlling by reservoirs, sand mining on river channel, soil and water conservation engineering measures.