Detection of main tidal frequencies using least squares harmonic estimation method

Abstract

In this paper the efficiency of the method of Least Squares Harmonic Estimation (LS-HE) for detecting the main tidal frequencies is investigated. Using this method, the tidal spectrum of the sea level data is evaluated at two tidal stations: Bandar Abbas in south of Iran and Workington on the eastern coast of the UK. The amplitudes of the tidal constituents at these two tidal stations are not the same. Moreover, in contrary to the Workington station, the Bandar Abbas tidal record is not an equispaced time series. Therefore, the analysis of the hourly tidal observations in Bandar Abbas and Workington can provide a reasonable insight into the efficiency of this method for analyzing the frequency content of tidal time series. Furthermore, applying the method of Fourier transform to the Workington tidal record provides an independent source of information for evaluating the tidal spectrum proposed by the LS-HE method. According to the obtained results, the spectrums of these two tidal records contain the components with the maximum amplitudes among the expected ones in this time span and some new frequencies in the list of known constituents. In addition, in terms of frequencies with maximum amplitude; the power spectrums derived from two aforementioned methods are the same. These results demonstrate the ability of LS-HE for identifying the frequencies with maximum amplitude in both tidal records.

Mengkaji Area Genangan Banjir Pasang Terhadap Penggunaan Lahan Pesisir Tahun 2020 Menggunakan Metode Geospasial di Kabupaten Pekalongan, Provinsi Ja

“…Data pengukuran Badan Informasi Geospasial berupa pasang surut pada bulan November tahun 2020 di stasiun Pekalongan. Menurut Mousavian et al (2012), analisis data yang digunakan untuk pasang surut adalah menggunakan analisis harmonik dengan metode kuadrat terkecil (Least Square), dimana analisa pasang surut yang dengan cara menguraikan gelombang pasang surut menjadi komponen-komponen harmonik dimana ketinggian muka air dikarenakan gelombang pasang surut yang merupakan hasil penjumlahan dari komponen-komponen gaya pembangkit pasang surut. Metode Least Square yang digunakan terdiri dari ERGTIDE, ERGRAM, ERGELV.…”

A Review of Modelling Approaches on Tidal Analysis and Prediction

“…(Foreman et al, 2009) develop and test a more versatile harmonic analysis technique that can accept randomly sampled data and embed the nodal and astronomical argument corrections and multiple inference calculations into an overdetermined matrix that is solved using singular value decomposition (SVD) technique. Many other researchers such as (Amiri et al, 2014;Najibi, et al, 2013;Mousavian and Hossainali, 2012;Ew and Ugust, 2003;Pawlowicz et al, 2002;Jay and Kukulka, 2003) apply harmonic analysis technique.…”

Determining precipitable water in the atmosphere of Iran based on GPS zenith tropospheric delays

“…Here, the least squares harmonic estimation has been used [Amiri-Simkooei 2007] because, this method has been efficiently used for analyzing the frequency content of various time series i.e. GPS observations [Amiri-Simkooei 2007], time series of Total Electron Content [Amiri-Simkooei and Asgari 2012], tidal data [Mousavian and Mashhadi-Hossainali 2012] and coordinate time series for detecting slow slip events [Mousavian and Mashhadi-Hossainali 2014].…”

“…In other words, the annual and seasonal frequencies are the first that approved by the hypothesis test of this method (see Amiri-Simkooei [2007] for further details). Moreover, since the least squares harmonic estimation is sensitive to the length of the input data [Mousavian and Mashhadi-Hossainali 2012], a detailed analysis of the frequency content requires a PW time series of much larger length. Further, the existence of annual and seasonal frequencies in the PW time series indicates that the adopted linear model does not distort the expected behavior of the PW parameter.…”