WHU-CASM-UGM2025 is a combined global gravity field model up to degree and order (d/o) of 10799 in spheroidal harmonics and 11000 in spherical harmonics, developed by Wuhan University and Chinese Academy of Surveying and Mapping. It is based on XGM2019e, and augmented by ultra-high resolution topographic potentials and altmetry products.
GRACE/GRACE-FO-derived time series of gridded terrestrial water storage anomalies with respect to the mean over the period 2003-01 - 2022-12.
The product is based on monthly COST-G RL02 GRACE/GRACE-FO Level-2B Products ( Meyer et al., 2025, doi: 10.5880/COST-G.ICGEM_02_L2) provided at 0.5° latitude-longitude grids as defined over all continental regions. The TWS anomaly grids are provided in NetCDF format, containing three different variables:
1) 'twsa': gravity-based terrestrial water storage anomaly
2) 'std_twsa': gravity-based terrestrial water storage anomaly standard deviations
3) 'flag_filter': Flag indicating the filter strength
File History:
The Copernicus Climate Change Service (C3S) groups its datasets into Climate Data Records (CDRs), representing major version releases, and Intermediate Climate Data Records (ICDRs), which only extend the existing data and do not involve any processing changes.
12 September 2025:
CDR: C3S_TWSA_GLOBAL_MONTHLY_200204_202503_v1.0.nc
Data set covering April 2002 to March 2025
5 January 2026:
ICDR: C3S_TWSA_GLOBAL_MONTHLY_200204_202509_v1.0.nc
Data set covering April 2002 to September 2025
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 from 4.8°S to 12.8°N in latitude and from 79.3°W to 66.7°W in longitude, with a grid spacing of 5' in both latitude and longitude. The input data include terrestrial and airborne gravity data, provided by the Instituto Geográfico Agustín Codazzi (IGAC), 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 standard deviation of about 16 cm.
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.
The MK_HREF2022 quasi-geoid model is a height reference surface for North Macedonia, referred to the GRS80 ellipsoid. It was computed by the Agency for Real Estate Cadastre of the Republic of North Macedonia, in cooperation with the Norwegian Mapping Authority (Kartverket), and it is given in the form of a regular grid, with resolution of 0.01° × 0.01°, within the limits of 40.8° < latitude < 42.4° and 20.4° < longitude < 23.1°. The model is based on a set of relatively new gravity data measured in 2014 (along the high accuracy levelling lines and in the frame of the regional gravimetric survey), in total 2470 points in mean-tide system. Stokes/Molodensky equations and the Fast Fourier transform technique were applied in the calculations, with use of the global geopotential model EGM2008. The computed quasi-geoid surface was fitted to 77 high quality GNSS/levelling points, fairly distributed throughout the territory of the country. The resulting height reference surface allows the conversion between ellipsoidal heights (ETRS89, epoch 1989.0) and heights in the official national height system (NVT1, datum Trieste 1875.0, normal orthometric heights). The inner accuracy of the calculated quasi-geoid model is 4.0 cm, while the outer accuracy (based on 1035 control GNSS/levelling measurements along levelling lines) is up to 10 cm. MK_HREF2022 is the official quasi-geoid model for North Macedonia since November 28, 2025.
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.