مؤسسه ژئوفیزیک دانشگاه تهران فیزیک زمین و فضا 2538-371X 45 4 2020 01 21 Least Squares Techniques for Extracting Water Level Fluctuations in the Persian Gulf and Oman Sea Least Squares Techniques for Extracting Water Level Fluctuations in the Persian Gulf and Oman Sea 99 119 72941 10.22059/jesphys.2019.269327.1007060 FA Saeed Farzaneh Assistant Professor, Department of Surveying and Geomatics Engineering, Faculty of Engineering, University of Tehran, Tehran, Iran Ehsan Forootan Lecturer, school of Earth and Ocean Sciences, Cardiff University, Cardiff, United Kingdom Kamal Parvazi Ph.D. Student Department of Surveying and Geomatics Engineering, Faculty of Engineering, University of Tehran, Tehran, Iran Journal Article 2018 11 28 Extracting the main cyclic fluctuations from sea level changes of the Persian Gulf and Oman Sea is vital for understanding the behavior of tides and isolating non-tidal impacts such as those related to climate and changes in the ocean-sea circulations. This study compares two spectral analysis methods including: Least Squares Spectral Analysis (LSSA) and Least Squares Harmonic Estimation (LSHE), to analyze satellite altimetry derived sea surface height changes of the Persian Gulf and Oman Sea. SSH data are derived from about 16 years of satellite altimetry observations (1992 to 2008), including the Topex/Poseidon and Jason-1 missions. By analyzing the real data, we extract significant tidal components in the spectrum of LSSA and LS-HE including those with the period of 62.07, 173.3, 58.71, 45.68, 88.86, 364.2 and 117.5 days, which are interpreted as Principal Lunar semi-diurnal, Luni-Solar Diurnal, Principal Solar Semi-diurnal, Principal Lunar Diurnal, GAM2, annual, Solar Diurnal periods are dominant in the level fluctuations. Moreover, some tidal components appear in the spectrum of LSSA and LS-HE, from which the Moon's semi-diurnal component  is dominant. Also, to evaluate the efficiency of these two techniques, we run three experiments in each extracted frequency from LSSA, LS-HE, and astronomical tide tables are separately used to predict the sea level in the Persian Gulf and Oman Sea for three years. The results of this prediction indicate that RMSE from LSSA, astronomical table, and LS-HE is 0.101 m, 0.093 m, and 0. 086 m, respectively. According to the results LS-HE is found a more efficient technique to analyze cyclic fluctuations from altimetry measurements. Extracting the main cyclic fluctuations from sea level changes of the Persian Gulf and Oman Sea is vital for understanding the behavior of tides and isolating non-tidal impacts such as those related to climate and changes in the ocean-sea circulations. This study compares two spectral analysis methods including: Least Squares Spectral Analysis (LSSA) and Least Squares Harmonic Estimation (LSHE), to analyze satellite altimetry derived sea surface height changes of the Persian Gulf and Oman Sea. SSH data are derived from about 16 years of satellite altimetry observations (1992 to 2008), including the Topex/Poseidon and Jason-1 missions. By analyzing the real data, we extract significant tidal components in the spectrum of LSSA and LS-HE including those with the period of 62.07, 173.3, 58.71, 45.68, 88.86, 364.2 and 117.5 days, which are interpreted as Principal Lunar semi-diurnal, Luni-Solar Diurnal, Principal Solar Semi-diurnal, Principal Lunar Diurnal, GAM2, annual, Solar Diurnal periods are dominant in the level fluctuations. Moreover, some tidal components appear in the spectrum of LSSA and LS-HE, from which the Moon's semi-diurnal component  is dominant. Also, to evaluate the efficiency of these two techniques, we run three experiments in each extracted frequency from LSSA, LS-HE, and astronomical tide tables are separately used to predict the sea level in the Persian Gulf and Oman Sea for three years. The results of this prediction indicate that RMSE from LSSA, astronomical table, and LS-HE is 0.101 m, 0.093 m, and 0. 086 m, respectively. According to the results LS-HE is found a more efficient technique to analyze cyclic fluctuations from altimetry measurements. https://jesphys.ut.ac.ir/article_72941_8173bb449e8496bb205f0baf74f62b13.pdf