基于一致性修正的宁波市甬江口设计高潮位研究

以位于宁波市甬江口的镇海站1951~2013年的年最高潮位序列为例,分别采用Spearman秩次相关检验、M-K检验方法分析其趋势变化,采用滑动秩和检验、Pettitt检验方法检查其变异点,发现该站年最高潮位存在显著上升趋势,且先后在1981、1996年发生跳跃,不同时期的样本并非来自同一总体。因此,选邻近的湖头渡为参证站,划分为1951~1980、1981~1995、1996~2013年三个阶段,建立了镇海站与湖头渡站的高潮位相关关系,以1996~2013年代表现状,对1951~1980、1981~1995年的实测年最高潮位进行修正,使修正后的序列满足频率分析的一致性要求。分别对经修正和未经修正的序列进行频率计算,表明同等频率下前者求出的设计值均大于后者,从而为甬江口涉水工程的规划建设和运行等提供更合理的依据。

Study on Design High Tide Level of Yongjiang Estuary Based on Consistency Correction

Taking 63 years (1951-2013) annual maximum tidal level sequences of Zhenhai station located in Yongjiang estuary for an example, Spearman rank correlation test and Mann-Kendall test were carried out for trend analysis. Change-point was detected by moving rank sum test and Pettitt test, and the results show that there is significantly rising trends in annual maximum tidal level series of Zhenhai station, and the abrupt changes took place in 1981 and 1996, i.e. annual maximum tidal level series could not meet the consistency hypothesis of traditional hydrological frequency calculation. Therefore, Hutoudu was selected as reference station, high tide level correlation relationship between Zhenhai station and Hutoudu station in the periods of 1951-1980, 1981-1995 and 1996-2013 were established. 1996-2013 were regard as current period, and the measured annual maximum tidal level during 1951-1980 and 1981-1995 were corrected according to the current situation to make sure the revised sequence was consistent. Results of frequency analysis for the revised annual maximum tide level series show that design high tide levels based on consistency correction are greater than that without consistency correction, which provides a more reliable basis for the wading engineering planning, construction and operation of Yongjiang estuary.