海南岛东南部新村港和黎安港潮汐特征及潮汐汊道P-A关系

ANALYSIS OF TIDES AND P-A RELATIONSHIPS OF XINCUN AND LI-AN LAGOONS, SOUTHEASTERN HAINAN ISLAND

以2013年8月实测的水位和流速资料为依据,基于调和分析和统计方法分析了海南岛东南部新村港和黎安港潟湖的潮汐和潮流特征及其分布规律,并探讨了潮汐汊道的P-A关系及其影响因素.结果表明,双湖附近海域潮汐以全日分潮01和K1为主,半日分潮M2次之,浅水分潮亦较显著,属于非正规的全日混合潮;调和常数反演的潮位与实测潮位基本吻合,表明潟湖水位主要受潮汐控制.此外,双湖均存在潮高日不等和涨落潮历时不等的现象,涨潮历时略大于落潮历时.新村港平均高潮位0.65m,较黎安港高0.15m;平均低潮位-0.28m,较黎安港低0.06m.新村港平均潮差0.50m,最大可能潮差1.63m;黎安港平均潮差0.36m,最大可能潮差1.22m;双湖平均潮差相差0.14m,而最大可能潮差相差较大,约0.41m.新村港平均潮差由口门向湾内有增大的趋势,而黎安港却恰好相反.实测和模拟结果显示新村港和黎安港潟湖潮流分布格局类似,都呈现出口门流速较大,潟湖内部区域流速较小（小于0.1 m/s）的分布规律,且落潮流略强于涨潮流.新村港和黎安港的P-A值与华南海岸潮汐汊道P-A关系回归线吻合较好,其中黎安港P-A值基本在华南海岸P-A关系回归线上,而新村港略微有点偏离,这说明新村港和黎安港潮汐汊道基本处于均衡状态.

Based on the observed water level during the August of 2013 in two coastal lagoons from southeastern Hainan Island, together with tidal cycle measurements of current velocities at four stations during August 19 to 21, 2013 （Xincun lagoon： S1 and S2 station, Li-An lagoon： S3 and S4 station） , the distribution patterns of tidal and tidal current are analyzed using harmonic analysis and statistical methods. At the same time, the P-A relationships of tidal inlets and its controlling factors are discussed. The results show that diurnal tides （O1 and K1） are the dominate constituents in the Xincun and Li-An lagoons, with semi-diurnal tides （M2） and shallow water tides being also significant. Harmonic analysis of tidal water levels shows that the tides of the two lagoons belong to irregular diurnal tides ; the water level hindcast using the harmonic constants indicates that the water level of the two lagoons during observation period is controlled mainly by the tide. Furthermore, there is a time asymmetry, with the duration of the flood tide being slightly longer than that of the ebb tide. The mean high tide level of the Xincun lagoon is 0.65m, 0.15m higher than that of the Li-An lagoon; the value of mean low tide level is -0.28m, 0.06m lower than that of the Li-An lagoon. The average and maximum tide ranges of the Xincun lagoon （0.50m and 1.63m, respectively） are higher than those of the Li-An lagoon （0.36m and 1.22m, respectively）. The tide range of the Xincun lagoon increases from the entrance towards the inner regions, but the Li-An lagoon presents an opposite trend. The in situ measurements of tidal current in the two lagoons, in combination with the simulation results, show that the tidal current of two lagoons has similar distribution patterns： the current in the entrance is relative strong, whilst in the inner regions of the lagoons it is weak （i.e., 〈0. 1m/s）. In addition, the ebb current was stronger than that of the flood. The P-A values of the two lagoons are consistent with the P-A relationships for the tidal inlets along the southern China coastlines, with a small deviation for the Xincun lagoon. The results indicate that the two tidal inlets are almost in an equilibrium state.