Colombia (QgeoidCOL2023)
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Authors: Q. Liu, et al.
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Created: 2023
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Resp: C.A. Franco Prieto
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Description:
QgeoidCOL2023 is a gravimetric quasi-geoid model for Colombia, computed by the Deutsches Geodätisches Forschungsinstitut (DGFI), Technical University of Munich. The area covered by the model is located between 280.65835° ≤ longitude ≤ 293.31995°, 12.841650°N ≤ latitude ≤ 4.817950°S with a grid spacing of 5' in both latitude and in longitude. The input data include terrestrial and airborne gravity data, provided by the Instituto Geográfico Agustín, as well as satellite altimetry data derived from the DTU21Gra model, all used at their original observation locations. A bias estimation for the airborne gravity surveys was performed using spherical radial basis functions (SRBFs), by comparing the data with the SaTop model up to degree and order 719 (Zingerle, 2022), since the surveys were conducted at different times and by different companies. The quasi-geoid computation is performed in the framework of a remove-compute-restore procedure, using the XGM2019 (Zingerle et al. 2020) as the gravity background model and the Earth2014 (Rexer et al. 2016) / ERTM2160 (Hirt et al. 2014) for the topographic gravity effects. The computation method is based on spherical radial basis functions (SRBFs), using the Shannon function and the Cubic Polynomial (CuP) function for the terrestrial and airborne data, respectively. The terrestrial, airborne, satellite altimetry and topography data observations were combined within a parameter estimation procedure, and the relative weights among them were determined by the method of variance component estimation (VCE). The comparison of the QgeoidCOL2023 quasi-geoid model against GPS/leveling shows differences with a stanndard deviation of about 16 cm.
Reference:
Q. Liu, M. Schmidt, L. Sánchez, L. Moisés, D. Cortez (2024). High-resolution regional gravity field modeling in data-challenging regions for the realization of geopotential-based height systems. Earth, Planets Space, 76, 35. DOI: 10.1186/s40623-024-01981-1
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