The PoliMI quasi-geoid based on windowed Least-Squares Collocation for the Colorado Experiment: ColWLSC2020

The ColWLSC2020 quasi-geoid model is a gravimetric model and has been computed by Department of Civil and Environmental Engineering (DICA), Politecnico di Milano. The model has been computed in the frame of the International Association of Geodesy Joint Working Group 2.2.2 "The 1 cm geoid experiment" and the so called "Colorado experiment". The area covered by the models is 108.5°E ≤ longitude ≤ 103.5°E, 36.5°N ≤ latitude ≤ 38°N with a grid spacing of 2' in both latitude and in longitude. The computation is based on the remove-compute-restore technique with XGM2106 being used as a reference field. The topographic effects were treated using a Residual Terrain Correction (RTC) by solving the spectral filter problem of RTC using Earth2014 and ERTM2160 models. The input gravity data include terrestrial and airborne data combined using Least-Squares Collocation (LSC). The final estimation was carried out using Windowed LSC (WLSC). The mean accuracy of the model, when compared against GSVS17 GPS/leveling, is at 3.6 cm level. The geoid model is provided in ISG format 2.0 (ISG Format Specifications), while the file in its original data format is available at the model ISG webpage.