长江口盐水入侵对径流变异和海平面变化的响应

基于1960—2019年长序列实测径流、潮位资料，采用Mann-Kendall检验和Theil-Sen估计分析了长江口径流变异和海平面变化趋势，结合MIKE21水动力模型和蒙特卡罗方法，提出了计算盐度超标率的方法，并对长江口盐水入侵风险进行了评估。结果表明：径流对数值的年方差和平均海平面高度分别呈显著下降和上升趋势；预计到2060年和2100径流对数值的年方差分别减小30%和60%,平均海平面高度分别上升0.2 m和0.4 m;海平面上升增大了长江口盐度超标率，河口中段的盐度超标率增幅相对明显；随着径流变异性的减小，长江口沿线盐度超标率呈交错增减变化；2060年和2100年长江口平均盐度超标率将从46.9%增大到52.2%和54.9%,其中海平面变化对长江口盐水入侵的影响显著大于径流变异。

Response of saltwater intrusion to runoff variability and sea level change in Yangtze River Estuary

Based on the measured runoff and tide level data of the long series from 1960 to 2019, Mann-Kendall test and Theil-Sen estimation were used to analyze the runoff variability of the Yangtze River Estuary and the trend of sea level change. In combination with MIKE21 hydrodynamic model and Monte Carlo method, a method for calculating the over standard rate of salinity was proposed, and the risk of saltwater intrusion into the Yangtze River inlet was assessed. The results show that the annual variance of runoff logarithms and the average sea level height show a significant downward and upward trend, respectively. It is estimated that the annual variances of runoff logarithms will decrease by 30% and 60% respectively by 2060 and 2100, and the average sea level height will increase by 0.2 m and 0.4 m respectively. The sea level rise increases the over standard rate of salinity at the Yangtze River Estuary, which is relatively obvious in the middle section of the estuary. With the decrease of runoff rheological anisotropy, the over standard rate of salinity along the Yangtze River Estuary rises and falls alternately. In 2060 and 2100, the over standard rate of the average salinity in the Yangtze River Estuary will increase from 46.9% to 52.2% and 54.9% respectively, in which the influence of sea level change on the saline intrusion in the Yangtze River Estuary is significantly greater than that of runoff variation.