调和常数及深度基准面的变化与历元订正

The Variation and Epoch Correction of Harmonic Constants and Chart Datum

分析和验证了黄海沿岸部分长期验潮站M2分潮振幅的线性变化趋势及深度基准面L值增大趋势,发现了长周期分潮调和常数不稳定性对深度基准面确定的影响。研究表明,在剥离了深度基准面变化趋势后,由年观测数据分析结果确定的深度基准面可达到厘米级的精度水平,而由月分析结果确定的深度基准面存在周期性变化,其深度基准面不宜直接计算确定。论证了对潮汐调和常数附加历元信息的必要性和基本方案。通过研究得出对统一深度基准建立的指导性结论。

The linear secular variation of the amplitude of the constituent M2 and chart datum at some tidal stations along the Yellow Sea coast are analyzed and verified. It is discovered that heavy influences on the determination of chart datum comes from the instability of the harmonic constants of the long period constituents. The researches indicate that while the secular trend is separated, the chart datum can be determined at the centimeter magnitude of accuracy from the harmonic constants obtained from annual tidal observations, and that it is inadequate to calculate chart datum with the monthly harmonic constants due to their periodic variation. The necessity to define a chart datum epoch and the fundamental schemes for the definition are demonstrated. Some directive conclusions for construction of a uniform chart datum are obtained from this paper.