Abstract
定期船観測のように繰り返し観測時刻にゆらぎのある場合に,潮汐信号のエイリアシングがどの程度成立するのかを研究した。エイリアシングすると調和解析が解けなくなる場合を設定して,人工的に観測時刻にゆらぎを与えたところ,観測誤差がなければ1秒未満のごく僅かなゆらぎによってエイリアシングの制約から外れ調和解析ができるようになった。ただし,誤差に対して強靭な解を得るためには,より大きな観測時刻のゆらぎが必要である。観測期間を2年間にした試算では,10分程度のゆらぎがあることが望ましかった。For the use of data sampled from ferryboats, aliasing of tidal signals in repeated observations was studied, when the sampling interval is inaccurate and fluctuates. With fluctuations of the sampling interval, artificial observations were made for synthesis of three constituents which cannot be determined by the harmonic analysis if they are aliased. When the observations are free from all noises, only slight fluctuation of less than one second enables the harmonic analysis, indicating departure from the aliased condition. In order to obtain a robust solution from observations with noises, on the other hand, the fluctuation needed was shown to be more than ten minutes for test cases from two years of data sampling.
Translated title of the contribution | Aliasing in Repeat Observations with Inaccurate Sampling Intervals |
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Original language | Japanese |
Pages (from-to) | 565-573 |
Number of pages | 9 |
Journal | 海の研究 |
Volume | 13 |
Issue number | 6 |
Publication status | Published - Nov 5 2004 |