中国东海岸港口潮位高频扰动现象分析

Temporal and spatial distribution of high-frequency tidal oscillations along the China East Coast

通过分析沿中国东海岸自北向南分布的5个重要港口或港口城市(石臼所、连云港、吕四、坎门、厦门)自1975~1997年间共22 a的潮位数据发现,与天文潮不同,实测潮位常伴有潮时提前、潮位偏高和高频扰动的现象。文章通过对潮位剩余值的特征分析,筛选出实测潮位伴随的高频扰动过程,分析了潮位高频扰动事件发生频率及其时空分布特征。研究结果表明:空间上,绝大部分潮位高频扰动是局地水文现象,少部分潮位高频扰动会沿岸传播;沿海各大港口普遍存在潮位高频扰动现象,江苏黄海沿岸港口出现机率高于其他地区,而在厦门港出现次数虽少,但能量最高。研究结果还表明,大部分潮位高频扰动现象与气象条件的关联度不明显,局地地形条件可能是触发潮位高频扰动的主要诱因。

Recorded tidal levels were analyzed at main harbors and harbored cities(Shiusuo,Lianyungang,Lusi,Kanmen,Xiamen)distributing from north to south along the China East Coast from 1975 to 1997.The analyses reveal that the measured tidal levels are often in pattern of advanced-phases,higher water levels and high-frequency oscillations,as compared to the predicted tidal levels.Through analysis on the characteristics of the tidal residuals,the high-frequency tidal oscillations events(HFTO)at the five main stations,which are often in company with the measured tidal levels,were screened out.The occurrences of HFTO were analyzed,along with their spatial and temporal distribution.Results show that the HFTO are locally hydrologic phenomena and few events can propagate along the coast.Most of the HFTO events have little dependence on meteorological conditions and it is suggested that the HFTO are tailored to local geomorphology instead.