中文摘要：

分析了不同海洋垂直基准面的含义及相互转换关系,研究了在高程基准和地球椭球面上表示深度基准面的实现途径,利用长期验潮站观测数据验证了不同时段平均水位和深度基准的确定精度水平。以南海为例,构建了深度基准面（L值）模型、正常高模型和大地高模型。分析和验证表明,长期验潮站的垂直基准可以实现cm级精度确定。更新和统一验潮站垂直基准确定,为海域垂直基准及转换模型提供了必要的基础条件。

英文摘要：

The vertical datums for hydrography and their relations were analysed and the technical approaches for expressing a chart datum on the height datum and Earth ellipsoidal surface were demonstrated.Among the three approaches for vertical datum transportation,developing a set of transportation models recent research has only focused on those relying on the single and discrete tidal station observations and calculations.The accuracy of the mean sea level（MSL）and the chart datum defined with the lowest normal low water was determined while different time spans were estimated with long period tidal station observations.This study indicates that the MSL under 5cm can be obtained with two years of observations,and a CD under 7cm root mean squares,along the coast of China.As an example,the CD model over the South China Sea and its separation from the height datum and Earth ellipsoidal surface are established through tide,mean sea surface,and sea surface topography models.Suggestions for unification tidal station CD calculation and establishment of a network for vertical datum control are put forward.