High-resolution residual terrain model and terrain corrections for gravity field modelling and geoid computation in Niger Republic
Abstract
In this study, we computed and presented grid maps of high-resolution terrain corrections and residual terrain model (RTM) as short-wavelengths of the gravity field and the geoid in Niger. We constructed RTM elevations from mean elevation surfaces corresponding to ~100 km and ~9 km of spatial scales and 3 arc-seconds SRTM data. The computations are performed at gravity stations and 1.5 arc-minute regular grid, out to 10 and 200 km for inner and outer zones respectively with the standard density of 2670 kg/m-3. The study area is characterized by low values of terrain effects. The indirect effects are lower than 10 cm for ~9 km and reach 1.8 m for ~100 km. In Niger, 98.44% of indirect effects are lower than 1 cm and 98.2% of direct effect are lower than 5 mgal for ~9 km. For ~100 km, 85.87% of indirect effects are lower than 10 cm and 89.77% of direct effects are lower than 5 mgal for ~100 km, and 98.77% of terrain corrections are lower than 1 mgal. We found out that height discrepancies between gravity stations and SRTM influences the precision of terrain effects. The results are value for applications in geodesy and geophysics that require accurate interpretations.
Keyword : gravity field, geoid, short-wavelengths, Residual Terrain Model, terrain corrections, SRTM, Niger
How to Cite
Ibrahim Yahaya, S., & El Azzab, D. (2018). High-resolution residual terrain model and terrain corrections for gravity field modelling and geoid computation in Niger Republic. Geodesy and Cartography, 44(3), 89-99. https://doi.org/10.3846/gac.2018.3787
This work is licensed under a Creative Commons Attribution 4.0 International License.
References
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Ibrahim Yahaya, S., El Brirchi, E. H., & El Azzab, D. (2017a). Impact of datum transformation on local variations of geometric geoid in Niger. Geodesy and Cartography, 43(4), 147-157. https://doi.org/10.3846/20296991.2017.1412615
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Jarvis, A., Reuter, H. I., Nelson, A., & Guevara, E. (2008). Holefilled seamless SRTM data V4 (Technical report). International Centre for Tropical Agriculture (CIAT). Retrieved from http://srtm.csi.cgiar.org
Kirby, J., & Featherstone, W. (2002). High-resolution grids of gravimetric terrain correction and complete Bouguer corrections over Australia. Exploration Geophysics, 33(4), 161. https://doi.org/10.1071/EG02161
Kloch, G., & Krynski, J. (2008, May). Towards optimisation of the determination of terrain corrections with the use of prism method. In The 7th International Conference “Environmental Engineering” (Vol. 3, pp. 1345-1353). Vilnius.
Nagy, D., Papp, G., & Benedek, J. (2000). The gravitational potential and its derivatives for the prism. Journal of Geodesy, 74(7), 552-560. https://doi.org/10.1007/s001900000116
Pavlis, N. K., Factor, J., & Holmes, S. (2007). Terrain-related gravimetric quantities computed for the next EGM. In 1st International Symposium of the International Gravity Field Service (IGFS) (Vol. 18, pp. 318-323). Harita Dergisi, Istanbul.
Pavlis, N. K., Holmes, S. A., Kenyon, S. C., & Factor, J. K. (2012). The development and evaluation of the Earth Gravitational Model 2008 (EGM2008). Journal of Geophysical Research, 117(B4), B04406. https://doi.org/10.1029/2011JB008916
Rechenmann, J. (1966). Catalogue des stations gravimétriques réoccupables en Afrique occidentale. Mesures effectuées de 1953 à 1965. Cahier d’ORSTOM – Série Géophysique, no. 7.
Rechenmann, J. (1969). Cartes gravimétriques du Niger: note explicative n°36. Office de la Recherche Scientifique et Technique Outre-Mer(ORSTOM). Paris.
Seeber, G. (2003). Satellite Geodesy. New York (2nd ed.). Berlin, New York: Walter de Gruyter. https://doi.org/10.1515/9783110200089
Seitz, K., & Heck, B. (2001). Tesseroids for the calculation of topographic reductions. In Abstracts Vistas for Geodesy in the New Millenium. IAG.
Torge, W. (2001). Geodesy (3th ed.). Berlin, New York: Walter de Gruyter. https://doi.org/10.1515/9783110879957
Tziavos, I. N., & Sideris, M. G. (2013). Topographic reductions in gravity and geoid modeling. In F. Sansò & M. G. Sideris (Eds.), Geoid Determination (Vol. 110, pp. 337-400). Berlin, Heidelberg: Springer. https://doi.org/10.1007/978-3-540-74700-0
Varga, M., & Bašić, T. (2015). Accuracy validation and comparison of global digital elevation models over Croatia. International Journal of Remote Sensing, 36(1), 170-189. https://doi.org/10.1080/01431161.2014.994720
Bureau Gravimétrique International. (2015). Land gravity data. Retrieved from http://bgi.omp.obs-mip.fr/data-products/Gravity-Databases/Land-Gravity-data
Drinkwater, M. R., Floberghagen, R., Haagmans, R., Muzi, D., & Po pes cu, A. (2003). GOCE: ESA’s first earth explorer core Mission. In G. Beutler, M. R. Drinkwater, R. Rummel, & R. Von Steiger (Eds.), Earth gravity field from space – from sensors to earth sciences (Vol. 17, pp. 419-432). Netherlands: Springer. https://doi.org/10.1007/978-94-017-1333-7_36
Forsberg, R. (1984). A study of terrain reduction, density anomalies and geophysical inversion methods in gravity field computation (Technical report No. 355). Department of Geodetic Science and Surveying, Ohio State University, Columbus.
Forsberg, R., & Tscherning, C. C. (2008). An overview manual for the GRAVSOFT Geodetic Gravity Field Modelling Programs (2nd ed.). Department of Geodetic Science and Surveying, No. 341. The Ohio State University, Columbus, Ohio.
Förste, C., Bruinsma, S. L., Abrikosov, O., Lemoine, J. M., Marty, J. C., Flechtner, F., Balmino, G., Barthelmes, F., & Biancale, R. (2014). EIGEN-6C4 The latest combined global gravity field model including GOCE data up to degree and order 2190 of GFZ Potsdam and GRGS Toulouse. GFZ Data Services. https://doi.org/10.5880/icgem.2015.1
Gilardoni, M., Reguzzoni, M., & Sampietro, D. (2015). GECO: a global gravity model by locally combining GOCE data and EGM2008. Studia Geophysica et Geodaetica, 60(2), 228-247. https://doi.org/10.1007/s11200-015-1114-4
Greigert, J., & Pougnet, R. (1965). Carte Géologique de la République du Niger. Bureau de recherches géologiques et minières France.
Grombein, T., Seitz, K., & Heck, B. (2013). Optimized formulas for the gravitational field of a tesseroid. Journal of Geodesy, 87(7), 645-660. https://doi.org/10.1007/s00190-013-0636-1
Hammer, S. (1939). Terrain corrections for gravimeter stations. Geophysics, 4(3), 184-194. https://doi.org/10.1190/1.1440495
Hayford, J., & Bowie, W. (1912). The effect of topography and isostatic compensation upon the intensity of gravity. Bulletin of the American Geographical Society, 44(6), 464-465. https://doi.org/10.2307/199909
Heiskanen, W. A., & Moritz, H. (1967). Physical geodesy. San Fran cisco, London.
Hirt, C., Featherstone, W. E., & Marti, U. (2010). Combining EGM2008 and SRTM/DTM2006.0 residual terrain model data to improve quasigeoid computations in mountainous areas devoid of gravity data. Journal of Geodesy, 84(9), 557-567. https://doi.org/10.1007/s00190-010-0395-1
Hirt, C., Gruber, T., & Featherstone, W. E. (2011). Evaluation of the first GOCE static gravity field models using terrestrial gravity, vertical deflections and EGM2008 quasigeoid heights. Journal of Geodesy, 85(10), 723-740. https://doi.org/10.1007/s00190-011-0482-y
Hwang, C., Wang, C. G., & Hsiao, Y. S. (2003). Terrain correction computation using Gaussian quadrature. Computers & Geosciences, 29(10), 1259-1268. https://doi.org/10.1016/j.cageo.2003.08.003
Ibrahim Yahaya, S., & El Azzab, D. (2018). Vertical accuracy assessment of global digital elevation models and validation of gravity database heights in Niger (Project).
Ibrahim Yahaya, S., El Brirchi, E. H., & El Azzab, D. (2017a). Impact of datum transformation on local variations of geometric geoid in Niger. Geodesy and Cartography, 43(4), 147-157. https://doi.org/10.3846/20296991.2017.1412615
Ibrahim Yahaya, S., El Brirchi, E. H., & El Azzab, D. (2017b). Mise en place d’une base de données géographique pour le calcul du géoïde gravimétrique au Niger. In Congrès International MORGEO2007 sur les Technologies Géospatiales: Applications et Perspectives, 16-17 Mai 2017. Casablanca, Maroc.
Ismail, Z. (2016). Détermination de l’exactitude d’un géoïde gravimétrique (Thèse de Doctorat en Géodésie). Université de Recherche Paris Sciences et Lettres, Ecole doctorale Astronomie et Astrophysique d’Ile de France, LAboratoire de REcherche en Géodésie, Paris.
Jarvis, A., Reuter, H. I., Nelson, A., & Guevara, E. (2008). Holefilled seamless SRTM data V4 (Technical report). International Centre for Tropical Agriculture (CIAT). Retrieved from http://srtm.csi.cgiar.org
Kirby, J., & Featherstone, W. (2002). High-resolution grids of gravimetric terrain correction and complete Bouguer corrections over Australia. Exploration Geophysics, 33(4), 161. https://doi.org/10.1071/EG02161
Kloch, G., & Krynski, J. (2008, May). Towards optimisation of the determination of terrain corrections with the use of prism method. In The 7th International Conference “Environmental Engineering” (Vol. 3, pp. 1345-1353). Vilnius.
Nagy, D., Papp, G., & Benedek, J. (2000). The gravitational potential and its derivatives for the prism. Journal of Geodesy, 74(7), 552-560. https://doi.org/10.1007/s001900000116
Pavlis, N. K., Factor, J., & Holmes, S. (2007). Terrain-related gravimetric quantities computed for the next EGM. In 1st International Symposium of the International Gravity Field Service (IGFS) (Vol. 18, pp. 318-323). Harita Dergisi, Istanbul.
Pavlis, N. K., Holmes, S. A., Kenyon, S. C., & Factor, J. K. (2012). The development and evaluation of the Earth Gravitational Model 2008 (EGM2008). Journal of Geophysical Research, 117(B4), B04406. https://doi.org/10.1029/2011JB008916
Rechenmann, J. (1966). Catalogue des stations gravimétriques réoccupables en Afrique occidentale. Mesures effectuées de 1953 à 1965. Cahier d’ORSTOM – Série Géophysique, no. 7.
Rechenmann, J. (1969). Cartes gravimétriques du Niger: note explicative n°36. Office de la Recherche Scientifique et Technique Outre-Mer(ORSTOM). Paris.
Seeber, G. (2003). Satellite Geodesy. New York (2nd ed.). Berlin, New York: Walter de Gruyter. https://doi.org/10.1515/9783110200089
Seitz, K., & Heck, B. (2001). Tesseroids for the calculation of topographic reductions. In Abstracts Vistas for Geodesy in the New Millenium. IAG.
Torge, W. (2001). Geodesy (3th ed.). Berlin, New York: Walter de Gruyter. https://doi.org/10.1515/9783110879957
Tziavos, I. N., & Sideris, M. G. (2013). Topographic reductions in gravity and geoid modeling. In F. Sansò & M. G. Sideris (Eds.), Geoid Determination (Vol. 110, pp. 337-400). Berlin, Heidelberg: Springer. https://doi.org/10.1007/978-3-540-74700-0
Varga, M., & Bašić, T. (2015). Accuracy validation and comparison of global digital elevation models over Croatia. International Journal of Remote Sensing, 36(1), 170-189. https://doi.org/10.1080/01431161.2014.994720