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Found 6 results.

The gravimetric geoid of São Paulo State: GEOID-SP-2020-GGM250

The geoid model of São Paulo State was computed using the updated and filtered gravimetric data and the new system of the normal height of the 2018 Brazilian Vertical Reference Frame (BVRF). For the ocean area, gravity anomalies of the DTU13 model with a resolution of 1’ were used. To quantify the terrain effects through the Residual Terrain Model procedure, the SRTM15+ DTM was used. The computation of the quasi-geoid model was performed by numerical integration through the Fast Fourier Transform (FFT). The Molodensky gravity anomaly was determined in a 5’x5’ grid and reduced and restored using the Residual Terrain Model (RTM) technique and the XGM2019e global gravity model truncated at degree and order 250. The geoid model was derived from the Bouguer gravity anomalies. The zero-order degree term was added in the final computation. The validation for the quasi-geoid model based on 291 GPS measurements in the leveling network has shown 18 cm RMS difference. 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 gravimetric geoid of São Paulo State: GEOID-SP-2020-GGM720

The geoid model of São Paulo State was computed using the updated and filtered gravimetric data and the new system of the normal height of the 2018 Brazilian Vertical Reference Frame (BVRF). For the ocean area, gravity anomalies of the DTU13 model with a resolution of 1’ were used. To quantify the terrain effects through the Residual Terrain Model procedure, the SRTM15+ DTM was used. The computation of the quasi-geoid model was performed by numerical integration through the Fast Fourier Transform (FFT). The Molodensky gravity anomaly was determined in a 5’x5’ grid and reduced and restored using the Residual Terrain Model (RTM) technique and the XGM2019e global gravity model truncated at degree and order 720. The geoid model was derived from the Bouguer gravity anomalies. The zero-order degree term was added in the final computation. The validation for the quasi-geoid model based on 291 GPS measurements in the leveling network has shown 18 cm RMS difference. 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 gravimetric quasi-geoid of São Paulo State: QGEOID-SP-2020-GGM250

The quasi-geoid model of São Paulo State was computed using the updated and filtered gravimetric data and the new system of the normal height of the 2018 Brazilian Vertical Reference Frame (BVRF). For the ocean area, gravity anomalies of the DTU13 model with a resolution of 1’ were used. To quantify the terrain effects through the Residual Terrain Model procedure, the SRTM15+ DTM was used. The computation of the quasi-geoid model was performed by numerical integration through the Fast Fourier Transform (FFT). The Molodensky gravity anomaly was determined in a 5’x5’ grid and reduced and restored using the Residual Terrain Model (RTM) technique and the XGM2019e global gravity model truncated at degree and order 250. The zero-order degree term was added in the final computation. The validation for the quasi-geoid model based on 291 GPS measurements in the leveling network has shown 18 cm RMS difference. 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 gravimetric quasi-geoid of São Paulo State: QGEOID-SP-2020-GGM720

The quasi-geoid model of São Paulo State was computed using the updated and filtered gravimetric data and the new system of the normal height of the 2018 Brazilian Vertical Reference Frame (BVRF). For the ocean area, gravity anomalies of the DTU13 model with a resolution of 1’ were used. To quantify the terrain effects through the Residual Terrain Model procedure, the SRTM15+ DTM was used. The computation of the quasi-geoid model was performed by numerical integration through the Fast Fourier Transform (FFT). The Molodensky gravity anomaly was determined in a 5’x5’ grid and reduced and restored using the Residual Terrain Model (RTM) technique and the XGM2019e global gravity model truncated at degree and order 720. The zero-order degree term was added in the final computation. The validation for the quasi-geoid model based on 291 GPS measurements in the leveling network has shown 18 cm RMS difference. 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 gravimetric geoid of São Paulo State based on Least Squares Collocation: GEOID-SP-2014-LSC

This gravimetric geoid model of São Paulo State, Brazil, has been computed by remove-restore technique using Least Squares Collocation (LSC). The reference geopotential model is GO_CONS_GCF_2_DIR_R3 up to degree and order 150. The SAM3s_v2 DTM has been used for the computation of terrain correction and other topographic and atmospheric effects. The mean free-air gravity anomaly (FA) in a 5'x5' grid over continent has been derived from the complete Bouguer anomalies (FA over the ocean has been obtained from the DTU10 satellite gravity model). Geoidal heights, referred to the GRS80 ellipsoid, have been computed on a grid of 5'x5' covering the area from 17°S to 28°S in latitude and from 56°W to 42°W in longitude. The resulting model has been verified by comparing them with 363 GPS/leveling points distributed all over the area, showing differences with a root mean square of 0.20 m. 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 gravimetric geoid of São Paulo State based on Fast Fourier Transformation with modified Stokes kernel: GEOID-SP-2014-FFT

This gravimetric geoid model of São Paulo State, Brazil, has been computed by remove-restore technique using Stokes integration through Fast Fourier Transform (FFT) with spheroidal Molodenskii-Meissl kernel modification. The reference geopotential model is GO_CONS_GCF_2_DIR_R5 up to degree and order 200. The SAM3s_v2 DTM has been used for the computation of terrain correction and other topographic and atmospheric effects. The mean free-air gravity anomaly (FA) in a 5'x5' grid over continent has been derived from the complete Bouguer anomalies (FA over the ocean has been obtained from the DTU10 satellite gravity model). Geoidal heights, referred to the GRS80 ellipsoid, have been computed on a grid of 5'x5' covering the area from 17°S to 28°S in latitude and from 56°W to 42°W in longitude. The resulting model has been verified by comparing them with 363 GPS/leveling points distributed all over the area, showing differences with a root mean square of 0.22 m. 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.

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