近50年东江三角洲潮汐运动的变化研究

Propagation of tidal waves in Dongjiang River Delta in the last 50 years

基于东江三角洲的5个水文观测站和东江下游的博罗流量观测站数据,分析近50 a来东江三角洲潮汐运动特征的变化。水文统计学方法表明上游石龙站点的水位和潮差变化程度远大于下游的大盛和泗盛围站点,且石龙站点低低潮曾发生于小潮,后发生于大潮时期,这一变化与潮汐分潮振幅变化相关。T_Tide调和分析得出的分潮振幅结果显示,各站点的振幅变化与水位和潮差变化相关,尤其石龙站点的半月分潮和半日分潮大小的转换能够说明低低潮发生时间的变化。此外计算出的地形指标变化,表明石龙站点因人类活动所导致的河床下切所引起的潮动力变化,对以上变化起到不同程度的影响作用。

Based on the water level dataset from five gaging stations and the runoff dataset from Boluo station during the last 50 years,the features of tidal waves propagation in Dongjiang River Delta were detected. The statistical hydrology method reveals the degree in variations of tidal wave propagation at upstream stations is larger than the degree at downstream stations,and the lowest low water once occurred on neap tides but then occurred on spring tides,this phenomenon shows the variations in amplitudes of tidal constituents are related with the variations in water levels and tidal ranges,especially the variations in fortnightly tidal constituent and semi-diurnal tidal constituent can explain the changes of time when the lowest low waters occurred. What′s more,the morphologic parameter exhibits the giant variations in tidal dynamics caused by the human activities at Shilong are responsible for the previous results.