Document Type : Research Paper
Author
Ph.D. Student of Surveying Engineering (Geodesy)
Abstract
The purpose of this research is to model the tidal phenomenon globally for all free waters of the world. In order to model this phenomenon, harmonic analysis method has been used. For the formation of the model for elevation of instantaneous level of water, nine main tidal components (Ssa, Mm, Mf, MO1, P1, K1, N2, M2, S2) have been taken into account in calculations. In order to form the cosine and sine coefficients of the mathematical model, a series of orthogonal and unit functions have been used in the study area. We used all the raw and main data of the TOPE × / POSEIDON altimeter satellite to estimate the unknowns. The information gathered by this satellite has been sent to us by the US Space Agency in a period of 10 years in the format of 117 CDs. The accuracy of the data collected by the TOPE × and POSEIDON altimeter is reported to be 2 cm and 3 cm respectively. In order to estimate the accuracy of the models derived from modeling calculations, the following tests are performed.
1 - Comparison of the results of the instantaneous water level elevation model with satellite observations in a period that has not been considered in modeling calculations.
2. Comparison of the model of mean water elevation with the models calculated by R.H.Rapp, 1994, and M.C.Kim, 1998.
3 - Comparison of the model of domains of tide major components of O1, K1, M2, S2 with the calculated values for the domain of these components in the position of 215 tidal stations selected throughout the world.
The average accuracy of the instantaneous water level elevation is estimated to be 1.677 mm. The mean differences from comparison of the instantaneous water level elevation model with satellite observations in a period that did not participate in modeling is calculated to be 13.25 cm. The average difference between the model of mean water level and the model by R.H.Rapp, 1994, is 13.01 cm. Furthermore, the mean differences obtained from comparison of the model of domains of components O1, K1, M2, S2 with the values provided for the domains of these components in tidal stations were 05.26cm, 05.76cm, 07.08cm, 11.48cm, respectively.
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