Abstract
The U.S. Defense Mapping Agency and the NASA Goddard Space Flight Center with the aid of other organizations such as The Ohio State University are cooperating in a joint effort to determine a significantly improved degree 360 spherical harmonic model representing the Earth’s gravitational potential. This new model will be of immediate use in defining a geoid undulation model that will be the basis for an enhanced WGS84 geoid.
The development of the new model is driven, in part, by the need to determine an accurate geoid undulation model that will be the reference surface for a World Height System to be implemented in the 1996 time period. In addition, the new geoid estimation will help satisfy increasingly important studies in ocean circulation (sea surface topography) and geodetic positioning through GPS.
The new model estimation will incorporate existing and new satellite data. New data will include GPS tracking of Topex/Poseidon, Doris tracking of several satellites, altimeter data from Topex/Poseidon, and ERS-1 and Doppler data from satellites at inclinations not covered or weakly represented in previous solutions.
The surface gravity data to be used in the new solution will be based on an updated 30’ mean anomaly data base developed at the DMA Aerospace Center. This new data set will incorporate a substantial amount of new data that has, and will, become available in Europe, the FSU, South America, Greenland, Africa, Asia and Antarctica. Anomaly values in areas such as Canada, the United States and Australia will be based on updated data files. This data will be used, after suitable corrections, to form normal equations that can be used with the satellite derived normal equations.
In addition, 30’x30’ mean anomalies derived from the Geosat Geodetic Mission satellite altimeter data will be used in the project. The file will be merged with the files based on the surface terrestrial data. In areas where no data exists, anomaly estimates will be made from new elevation data through topographic isostatic models to ultimately yield a global 30’ anomaly file. In addition, an updated l°xl° anomaly file based on terrestrial data (both land and ocean) will be determined.
The final stage of the data processing will be the development of several degree 360 models using different data sets and weighting procedures. The current plan is to use existing software, for the combination solution, with minimum modifications to assure a timely effort. Several preliminary models will be made available to the international community for evaluation. A final model will be selected based on extensive tests of the preliminary models. The final model and accuracy estimates will be released in mid 1996. The model will be used to determine accurate geoid undulations that will be available in gridded form.
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References
Balasubramania, N. (1994), Definition and Realization of a Global Vertical Datum, Rept. No. 427, Dept. of Geodetic Science and Surveying, The Ohio State University, Columbus.
Bašić, T. and R.H. Rapp (1992), Oceanwide Prediction of Gravity Anomalies and Sea Surface Heights Using Geos- 3, Seasat and Geosat Altimeter Data and ETOP5U Bathymetric Data, Rept. No. 416, Dept. of Geodetic Science and Surveying, The Ohio State University, Columbus.
Bašić, T., H. Denker, P. Knudsen, D. Solheim, and W. Torge (1990), A New Geopotential Model Tailored to Gravity Data in Europe, in Gravity, Gradiometry and Gravimetry, ed. by R. Rummel and R.G. Hipkin, IAG Symp. 103, pp. 109–118, Springer-Verlag.
Denker, H. and R.H. Rapp (1990), Geodetic and Oceanographic Results from the Analysis of 1 Year of Geosat Data, J. Geophys. Res., 95 (C8), 13,151–13,168.
Denker, H., D. Behrend, W. Torge (1993), The European Geoid Project: Progress Report, in Pros. of Session G3, European Geophysical Society, XVIII General Assembly, Wiesbaden, Germany, Kort-OG Matrikelstyrelsen (Geodetic Division), Denmark.
Featherstone, W.E., and J.G. Olliver (1993), The Gravimetric Geoid of the British Isles Computed Using a Modified Stokes’ Integral, in Proc. of Session G3, European Geophysical Society, XVIII General Assembly, Wiesbaden, Germany, Kort-OG Matrikelstyrelsen (Geodetic Division), Denmark.
Forsberg, R. (1987), A New Covariance Model for Inertial Gravimetry and Gradiometry, J. Geophys. Res., 92, 1305–1310.
Gruber, T. and M. Anzenhofer (1993), The GFZ 360 Gravity Field Model, presentation at the European Geophysical Society mtg., Wiesbaden.
Kenyon, S. (1994), Mean Anomaly Computation, prepared for WG II, DMAAC, St. Louis, MO, July.
Knudsen, P. (1994), Estimation of Sea Surface Topography in the Norwegian Sea Using Gravimetry and Geosat Altimetry, Bulletin Geodesique, 66, 1.
Kumar, M. (1994), A New Concept for Defining and Surveying Time-Invariant Bathymetry, 13th UN Regional Cartographic Conference for Asia and the Pacific, Beijing.
Lerch, F.-J. (1991), Optimum Data Weighting and Error Calibration for Estimation of Gravitational Parameters, Bulletin Geodesique, 65, 44–52.
Lerch, F.J., N.K. Pavlis and J.C. Chang (1993), High-Degree Gravitational Modeling: Quadrature Formulae versus a Block-Diagonal Normal Matrix Inversion, presented at the EGS Meeting, Wiesbaden, Germany.
Malys, S. and J. Slater, (1994) Maintenance and Enhancement of the World Geodetic System 1984, paper presented at the ION Conference, Salt Lake City.
Marsh, J.G., F.J. Lerch, C.J. Koblinsky, S.M. Klosko, J.W. Robbins, R.G. Williamson, and G.B. Patel (1990), Dynamic Sea Surface Topography, Gravity and Improved Orbit Accuracies from the Direct Evaluation of SEASAT Altimeter Data, J. Geophys. Res., 95 (C8), 13,129–13.150.
Milbert, D. (1993), GEODD93: A High Resolution Geoid for the United States, G&GS Update, Coast and Geodetic Survey, Vol. 5, No. 3, Silver Spring, MD.
Nerem, R.S., B.D. Tapley, and C.-K. Shun (1990), Determination of the Ocean Circulation Using GEOSAT Altimetry, J. Geophys. Res., 95 (C8), 3163–3179.
Nerem, R.S. et al. (1994), A Preliminary Evaluation of Ocean Topography from the TOPEX/POSEIDON Mission, J. Geophys. Res. - Oceans, in press.
Nerem, R.S. et al. (1994), Gravity Model Development for TOPEX/POSEIDON Joint Gravity Models 1 and 2, J. Geophys. Res. - Oceans, in press.
Nerem, R.S., C. Jekeli, W.M. Kaula (1994), Gravity Field Determination and Characteristics: Retrospective and Prospective, J. Geophys. Res. - Solid Earth, in press.
Pavlis, N. and R.H. Rapp (1990), The Development of an Isostatic Gravitational Model to Degree 360 and Its Use in Global Gravity Modelling, Geophys. J. Int., 100, 369–378.
Rapp, R.H. and N. Balasubramania (1992), sA Conceptual Formulation of a World Height System, Rept. No. 421, Dept. of Geodetic Science and Surveying, The Ohio State University, Columbus.
Rapp, R.H. and N.K. Pavlis (1990), The Development and Analysis of Geopotential Coefficient Models to Spherical Harmonic Degree 360, J. Geophys. Res., 95, 21,885–21,911.
Rapp, R.H. and Y.M. Wang (1994), Dynamic topography estimates using Geosat data and a gravimetric geoid in the Gulf Stream Region, Geophys. J. Int., 117, 511–528.
Rapp, R.H. (1993), A World Vertical Datum Proposal, presented at meeting of LAG/Special Study Group 5.149, IOS Deacon Laboratory, Wormly, England.
Rapp, R.H. (1994), Global Geoid Determination, in Geoid and its Geophysical Interpretations, ed. by Vaniček and Christou, CRC Press, Boca Raton.
Rapp, R.H. (1994), Y. Yi and Y.M. Wang, Mean Sea Surface and Geoid Gradient Comparisons with TOPEX Altimeter Data, J. Geophys. Res. - Oceans, in press.
Rapp, R.H., Y.M. Wang, and N.K. Pavlis (1991), The Ohio State 1991 Geopotential and Sea Surface Topography Harmonic Coefficient Models, Rept. No. 410, Dept. of Geodetic Science and Surveying, The Ohio State University, Columbus.
Stammer, D. and C. Wunsch (1994), Preliminary Assessment of the Accuracy and Precision of TOPEX/ POSEIDON Altimetric Data with Respect to the Large Scale Ocean Circulation, Journal of Geophysical Research - Oceans, in press.
Tscherning, C.C. (1983), The Role of High Degree Spherical Harmonic Expansions in Solving Geodetic Problems, in Proc. Int. Assoc. of Geodesy Symposia, IUGG XVII General Assembly, Vol. 1, pp. 431–441, Dept. of Geodetic Science and Surveying, The Ohio State University, Columbus.
van Hee, D. (1987), Preliminary Results from the Processing of a Limited Set of Geosat Radar Altimeter Data, Johns Hopkins APL Technical Digest, Vol. 8, No. 2, 201–205.
Visser, P.N.A.M., K.F. Walker, B.A.C. Ambrosius (1993), Dynamic Sea Surface Topography from GEOSAT Altimetry, Marine Geodesy, Vol. 16, pp. 215–239.
Wang, Y.M. and R.H. Rapp (1994), Comparison Between Orthonormal and Spherical Harmonic Expansions of Dynamic Topography Using Topex Data, EOS, AGU, Vol. 75, No. 16, p. 108, Abstract.
Xu, P. and R. Rummel (1991), A Quality Investigation of Global Vertical Datum Connection, Netherlands Geodetic Commission, New Series, No. 34, Delft.
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Rapp, R.H., Nerem, R.S. (1995). A Joint GSFC/DMA Project for Improving the Model of the Earth’s Gravitational Field. In: Sünkel, H., Marson, I. (eds) Gravity and Geoid. International Association of Geodesy Symposia, vol 113. Springer, Berlin, Heidelberg. https://doi.org/10.1007/978-3-642-79721-7_42
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DOI: https://doi.org/10.1007/978-3-642-79721-7_42
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