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潮汐调和分析方法的探讨 |
张凤烨1,2, 魏泽勋1,2, 王新怡1,2, 王永刚1,2, 方国洪1,2
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1.海洋环境科学与数值模拟国家海洋局重点实验室;2.国家海洋局第一海洋研究所
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摘要: |
为实现对不等时距潮汐资料的分析, 基于Matlab 内部函数功能, 提出了一种调和分析方法。基于这种方法, 分别对大连、北海两个站位1985 年的全年等时间间距取样的资料和非等时间间距取样的资料进行了调和分析, 结果显示, 由等时间距资料和非等时间距资料计算的调和常数基本吻合。对大连、北海两个站位的全年资料进行多个不同时间间距取样分析, 发现当分潮频率大于取样频率的二分之一时, 分潮发生频率混淆。若分潮周期明显大于样品长度, 该分潮的分析结果产生很大误差。最后得出结论为: 此调和分析方法, 适合对非等时间间距、非连续潮汐潮流资料进行调和分析, 并且能够获得与传统方法精度相当的结果。 |
关键词: Matlab 潮汐 调和分析 取样 |
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基金项目:国家自然科学基金项目(40976016); 国家海洋局第一海洋研究所基本科研业务费专项资金项目(GY02-2010G07); 国家高技术研究发展计划(863 计划)重点项目(2009AA121402) |
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Tidal harmonic analysis |
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Abstract: |
To analyze observational data sampled at non-equal time intervals, we devised a least squares method of tidal harmonic analysis, based on Matlab’s function. By this method, the harmonic constants were almost the same with observational data sampled at either equal time intervals or and non-equal time intervals at Dalian and Beihai in 1985. The harmonic analysis with data sampled at different time intervals showed that frequency aliasing occured when the tidal frequency was more than 1/2 of the sampling frequency, and there were great error when the period of the constituent was significantly larger than the sample length. It was shown that our method could obtain results of the same precision of the traditional method in analyzing discontinuous data or data sampled at non-equal time intervals. |
Key words: Matlab tide harmonic analysis sample |