摘要:
文中提出了浅水港口潮汐预报准调和方法的两个改进方案.一个是在方国洪等(1981)《浅水港口潮汐预报的一个方法》基础上,增加14周/日、16周/日以及与前期潮汐状况有关的浅水准调和项共6项(方案Ⅰ);另一个在是王骥(2001)提出的方案基础上改进的方案,该方案与方案Ⅰ相比,增加了5个准调和项(方案Ⅱ).这两个方案选用相同的57个调和分潮,但分潮的组合及派生出的准调和项有所不同.方案Ⅰ用40项准调和项表示浅水效应,方案Ⅱ则包含长周期、全日、半日周期的准调和项18项.经过大量实测水位资料的分析和预报检验,表明改进后两个方案对浅水港口潮汐的预报精度均较改进前的准调和方法和传统调和法有明显提高,对第一类浅水港(以吴淞港为例),文中所列的8项预报指标都有显著提高,特别是低潮时均方差由26.8min降至15.1min;对第二类浅水港(以成山角为例),高潮时均方差显著减小,由39.6min减至26.7min.
Abstract:
Two improved schemes(Ⅰand Ⅱ) of quasi-harmonic method for tide prediction of shallow water ports are proposed.SchemeⅠadds 14 circles perday,16 circles perdya and 6 quasi-harmonic terms which are related to previous tide status based on Fang Guohong(2001).SchemeⅡis the method proposed by Wang Ji in 2001 and adopts another 5 quasi-harmonic terms based on the SchemeⅠ.Both of them adopt the same 57 harmonic constituents.However,how to group the constituents and what kind of quasi-harmonic terms are derived from the constituents are different.It takes 40 quasi-harmonic terms to denote the shallow water effect in the SchemeⅠ.The 18 terms of long period,diurnal and semidiurnal quasi-armonic terms are included in the SchemeⅡ.The results show that the precision of both SchemeⅠand SchemeⅡ is obviously improved compared with Fang Guohong(2001) and traditional standard harmonic analysis method.For the first type shallow water ports,such as Wusong Station,all 8 prediction indexes are obviously improved.Especially the roo-tmean-square of low water time is reduced from 26.8 to 15.1 min.For the second type shallow water ports,such as Chensanjiao Station,the root-mean-square of high water time is reduced remarkably from 39.6 to 26.7 min.
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