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Regional Models

Auvergne - France (Auvergne-ITUGRG2021)


  Author: Sakil et al.     Created: 2021    Resp: ITU-GRG  
      Status: PUBLIC    
Description:
The Auvergne-ITUGRG2021 is a gravimetric geoid model that is computed for the Auvergne test area as part of methodological research by the Gravity Research Group in the Department of Geomatics Engineering, Istanbul Technical University (ITU-GRG). The area covered by the model is between 45°N ≤ latitude ≤ 47°N and 1°E ≤ longitude ≤ 5°E and the computed geoid model has a 2' grid spacing in both latitude and longitude. The computation is based on the Least Squares Modification of Hotine's Integral with Additive Corrections (LSMHA) method. In the computations, the dataset released by Institut Géographique National (IGN) for scientific purposes (Duquenne, 2006) is used. This dataset includes 244009 gravity observations with 1-2 mGal accuracy, a digital elevation model, and 75 GNSS/leveling benchmarks for validating the calculated model. In the computation, the XGM2016 global geopotential model up to degree/order 500 is used. The integration radius for Hotine's integral is chosen as 0.5°. In result of the external validation, the accuracy of this geoid model is obtained as 3.8 cm, which is improved to 2.7 cm after 4-parameter fitting (the provided model is the one before fitting).

Reference:
F.F. Sakil, S. Erol, A. Ellmann, B. Erol (2021). Geoid modeling by the least squares modification of Hotine's and Stokes' formulae using non-gridded gravity data. Computers and Geosciences, 156, 104909. DOI: 10.1016/j.cageo.2021.104909
H. Duquenne (2006). A data set to test geoid computation methods. Harita Dergisi (Map Journal), Special Issue, 18, 61-65.


France