National Report of Denmark

1995-1998

IUGG General Assembly

Birmingham, UK

Frede Madsen

National Survey and Cadastre - Denmark

Rentemestervej 8, DK 2400 København SV

Tlf. +4535875286

e-mail: fm@kms.dk

http://www.kms.dk

This report to the International Association of Geodesy, within the International Union of Geodesy and Geophysics, covers the scientific activities in Denmark during the 4-year peroid at the following institutions:

National Survey and Cadastre, Department of Geodesy (KMS)

University of Copenhagen, Department of Geophysics (UOC).

The geodetic activities are to a large extent carried out as a cooperation between the two mentioned institutions. Further a number of the projects are carried out within the framework of the Nordic Geodetic Commission, which facilitates the geodetic work going on in Iceland, Norway, Sweden, Finland and Denmark.

Geodetic networks

KMS has participated in the establishment of the European Vertical GPS Reference Network carrying out GPS observations at five tide gauge stations - four in Denmark and one in the Faroe Islands.

New geodetic networks based on ETRS89 has been introduced in Denmark and the Faroe Islands.

The third order precise levelling network in Denmark is completed and a new vertical datum has been introduced. Furthermore all observations have been introduced in the Unified European Levelling Network 1995 (UELN-95)

Satellite positioning

Three permanent GPS reference stations are established in Denmark providing observations to a number of services aiming at an improvement of the GPS code observations.

In Greenland two permanent GPS reference stations are in operation - one in Thule (Pittufik) in cooperation with Jet Propulsion Laboratory, USA and one in Scoresbysund (Ittoqqortoormiut). The permanent station in Thule collects data from GPS and GLONAS.

Gravimetry

The gravity surveys in Greenland covering the ice free part of Greenland have been completed resulting in an average spacing between gravity points of approx. 20 km.

New gravity projects have been initiated by developing methods for airborne gravity observations through the Airborne Geoid Mapping System for Coastal Oceanography (AGMASCO). AGMASCO is a cooperation between Germany, Portugal, Norway and Denmark. Surveys with the system for airborne gravity observations has been performed in the Polar Sea North and East of Greenland.

Altimetry

A number of investigations using altimeter observations from the ERS, GEOSAT and Topex-Poseidon satellites have been performed. This includes

- global gravity field determinations

- global ocean tide models

- mean sea level changes

- combinations with other remote sensing data (temperature and ocean colour).

Further, a digital terrain model for Greenland using all available data such as altimetry, radar observations from aircrafts and photogrammetry has been established.

Geoid determinations

The work with the Nordic geoid has been continued and a new version was established during 1996. This version includes new data especially from eastern-european countries, as well as new data from joint Nordic marine gravimetry projects in the Baltic and the North Sea.

A number of investigations on geoid determinations and inversion problems has been performed related to the North Sea and the North Atlantic area.

Ice sheet monitoring

Several sites at the Greenland ice sheet have been monitored by GPS, airborne laser altimetry and SAR interferometry in order to assess height changes and intercomparison of methods. The ice sheet measurements have been carried out in cooperation wwith University of Copenhagen and the Danish Center for Remote Sensing.

July 15, 1999

Selected Publications:

1996:

Andersen, O. Ba.: Using Inversion for Ocean tide Mapping. In: Inverse Methods: Interdisciplinary elements of methodology, computation, and applications, B.H. Jacobsen et al. (eds.), Lecture Notes in Earth Sciences, 63, Springer Verlag, Berlin, 239-246, 1996.

Andersen, O. Ba., and P. Knudsen: Global analysis of the altimetric gravity field from the ERS-1 geodetic mission. Presented, EGS XXI General Assembly, Den Haag, May 1996.

Andersen, O. Ba., and P. Knudsen: Multi-satellite ocean tide modelling. How can we improve K1? Presented TIDAL SCIENCE 1996, London, October, 1996.

Andersen, O.Ba., P.Knudsen, and C.C.Tscherning: Investigation of methods for global gravity field recovery from dense ERS-1 geodetic mission altimetry. In: Global Gravity Field and its temporal variations. (Rapp, Cazenave & Nerem, Ed.), IAG Symposia no. 116, pp. 218 - 226, Springer Verlag, 1996.

Andersen, O.Ba., T. Knudsen, P. Knudsen: Global Analysis Of The Seasonal Cycle from ATSR Sea Surface Temperature Data and Topex/Poseidon Altimetry Presented, EGS XXI General Assembly, Den Haag, May 1996.

Andersen, O. B., and R. Forsberg: Danish precision gravity reference network. Kort & Matrikelstyrelsen, Skrifter 4. rk, bd. 4 (Publications of the National Survey and Cadastre, Publications 4. series, vol. 4), 1996.

Arabelos, D. and C.C.Tscherning: Support of spaceborn gravimetry data reduction by ground based data. In: H.. Suenkel (Ed.). CIGAR IV, final report, pp. 91 - 145, Graz, June, 1996.

Arabelos, D. and C.C.Tscherning: Collocation with finite covariance funstions. International Geoid Service Bulletin No 5, pp. 117 - 135, 1996a.

Borre, K.: Estimation of Phase Ambiguities in GPS. In: Proceedings from 2rd International Conference "Civil Engineering and Environment", pp. 26 - 27, 1996.

Ekholm, S.: A full coverage, high-resolution, topographic model of Greenland, computed from a variety of digital elevation data. J. Geophys. Res., B10, 21961 - 21972, 1996.

Forsberg, R.: The geoid of Greenland - a reference surface for remote sensing. Proc. 6th Workshop on mass balance of the Greenland ice sheet and related topics, Jan. 1996, Copenhagen, published by GEUS, 1996.

Forsberg, R., S. Ekholm, K. Keller: KMS data and activities in Greenland relative to INSAR. Pres. Workshop of Glaciological Applications of Satellite Radar Interferometry, March 1996, JPL/Pasadena, 1996.

Forsberg, R. and J.M. Brozena: Airborne geoid measurements in the Arctic ocean. Proc. International Symposium on Gravity, Geoid and Marine Geodesy, Tokyo, Sept. 1996.

Forsberg R., K. Hehl, L. Bastos, A. Giskehaug, U. Meyer: Development of an airborne geoid mapping system for coastal oceanograph (AGMASCO). Proc. International Symposium on Gravity, Geoid and Marine Geodesy, Sept. 1996, Tokyo, 1996.

Forsberg, R., D. Solheim and J. Kaminskis: Geoid of the Nordic and Baltic area from gravimetry and satellite altimetry. Proc. International Symposium on Gravity, Geoid and Marine Geodesy, Sept. 1996, Tokyo, 1996.

Jiang, Z., C.Poitevin and C.C.Tscherning: Nouvelles Solutions pour le geoide gravimetrique Belgique-Luxembourg. Rapp. Geiode no.22, ENSG/LAREG/IGN, St. Mande, France, 1996.

Jiang, Z., C. Poitevin and C.C.Tscherning: Adjustment combine du geoide en prenant differentes realisations par les pays voisins. Rapp. Geiode no. 23, ENSG/LAREG/IGN, St. Mande, France, 1996.

Knudsen, P. and O. B. Andersen: Ocean bottom topography from ERS-1 altimeter data. Earth Observation Quarterly (EOQ), 51, ESRIN, 16-18, 1996.

Knudsen, P. , and O. Ba. Andersen: Improved Recovery of the Global Marine Gravity Field from the GEOSAT and the ERS-1 Geodetic Mission. Altimetry Proceedings GraGeoMar96,Tokyo 1996.

Knudsen, P. and O. Ba. Andersen: Global Marine Gravity Field from the ERS-1 and GEOSAT Geodetic Mission Altimetry. J. Geophys Res, (ERS-1 special issue), 1996.

Knudsen, P., O.Ba. Andersen, T. Knudsen: ATSR sea surface temperature data in a global analysis with TOPEX/POSEIDON altimetry. Geophysical Research Letters vol 23, pp.821-824, 1996.

Knudsen, T.: Fusion of Altimetry, Atmospheric Pressure and Sea Surface Temperature Observations from the North Atlantic and Adjacent Seas Using Empirical Orthogonal Functions. In: Ranchin & Wald (eds): Proceedings, Fusion of Earth Data Conference. EARSel/SEE/Ecole des Mines de Paris, 1996.

Leeuwenburgh, O., C.C. Tscherning, P. Knudsen and O.B. Andersen: Preliminary investigation of ERS-1 full waveform data on the Greenland ice sheet. Presented, EGS XXI General Assembly, Den Haag, May 1996.

Roman D. R., B. Csatho, K. Jezek, R. H. Thomas, W. B. Krabill, R. von Frese, R. Forsberg: A comparison of geoid undulation models for west-central Greenland. Journal of Geophysical Research, (in print). 1996.

Shum, C. K., P. L. Woodworth, O. Ba. Andersen, G. Egbert, O. Francis, C. King, S. Klosko, C. Le Provost, X. Li, J. Molines, M. Parke, R. Ray, M. Schlax, D. Stammer, C. Tierney, P. Vincent, and C. Wunch Accuracy assesment of recent ocean tide models J. Geophys. Res., 1996.

Smith, A. J. E., and O. Ba. Andersen Errors in recent ocean tide models: origin and cause Presented TIDAL SCIENCE 1996, London, October1996 1996.

Strykowski, G.: Borehole data and stochastic gravimetric inversion. PhD-thesis, University of Copenhagen, Kort & Matrikelstyrelsen, Skrifter 4. rk, bd. 3 (Publications of the National Survey and Cadastre, Publications 4. series, vol. 3), 1996.

Strykowski, G.: Improving the planar isotropic covariance models. Proceedings Interdisciplinary Inversion Conference 1995, University of Aarhus, Denmark. In: Jacobsen B.H., Mosegaard K. and Sibani P. (eds.), Inverse Methods, Interdisciplinary Elements of Methodology, Computation, and Applications, Lecture Notes in Earth Sciences 63, Springer Verlag, 254-261, 1996.

Strykowski, G.: Formulation of the mathematical frame of the joint gravimetric-seismic modelling problem based on analysis of regionally distributed brehole data. Proc. International Symposium on Gravity, Geoid and Marine Geodesy, sep 1996, Tokyo, 1996.

Tscherning, C.C.: Isotropic reproducing kernels for the inner of a sphere or spherical shell and their use as density covariance functions. Math. Geology, Vol 28, pp. 161 -168, 1996.

1997:

Andersen, O. B., and O. Leeuwenburgh: Quarter diurnal tides and seasonal tidal amplitude variations in the northwest European shelf region from altimetry and tide gauges. Proceedings Monitoring the oceans in the 2000s: an integrated approach, poster 2-18, Biarritz, France, October, 1997.

Andersen, O. B., and P. Knudsen: Multi-satellite Ocean tide modelling - the K1 constituent. In Tidal science, Eds R. Ray and P. L. Woodworth, Progress in Oceanography, 1997.

Andersen, O. B., and P. Knudsen: Global gravity field from the ERS_1 and the Geosat geodetic mission altimetry - The Mediterranean sea. Proceedings of the 3rd ERS symposium Florence, 1997.

Andersen, O. B., and P. Knudsen: Global marine gravity field from the ERS-1 and Geosat geodetic mission altimetry. J. Geophys. Res., Serie C, 1997.

Andersen O. B., and P. Knudsen: Global gravity field from the ERS_1 and the Geosat geodetic mission. Presented, EGS XXII General Assembly, Vienna, may 1997.

Andersen, O. B. and P. Knudsen: Multi-mission OceanTide Modelling in the Southern Ocean. Presented AGU spring meeting, Baltimore, Maryland, may, 1997.

Andersen O. B., R. Forsberg, P. Knudsen, D. McAdoo and S. Laxon: Comparison of recent altimetric and shipborne gravity over ice-covered and ice-free polar seas. Proceedings of the Scientific assembly of the International Association of Geodesy-IAG97, Rio de Janeiro, Brazil, 1997.

Bamber, J.L., S. Ekholm, W.L. Krabill: A digital elevation model of the Greenland ice sheet and validation with airborne laser altimeter data. Geophys. Rev. Lett., 1997.

Bastos, L., R Forsberg, A Giskehaug, K Hehl, U Meyer, L Timmen: The AGMASCO airborne gravity and airborne altimeter survey in Skagerrak. Presented Symposium G6, European Geophysical Society General Assembly, Vienna, 1997.

Bastos, L., R Forsberg, A Giskehaug, U Meyer, K Hehl, L Timmen: An airborne geoid mapping system for regional sea-surface topography: Application to the Skagerrak and Azores areas. Proceedings of the Scientific assembly of the International Association of Geodesy-IAG97, Rio de Janeiro, Brazil, 1997.

Ekholm, S.: Determination of Greenland surface topography from satellite altimetry and other elevation data. Kort & Matrikelstyrelsen, Technical Report no. 9, 21pp, in press, 1997.

Ekholm, S., K. Keller, and J.L. Bamber: Unusual surface topography from digital elevation models of the Greenland ice sheet. Submitted to Geophys. Res. Lett., 1997.

Engsager, K.: Integration of Satellite Data in Local Geodetic Networks, Implementation and Numerical Analysis. Publ. of National Survey and Cadastre, Denmark, 4.series, vol. 5, in print, 1997.

Forsberg, R.: The Use of Spectral Techniques in Gravity Field Modelling. Physics and Chemistry of the Earth, 1997.

Forsberg, R., W Featherstone: Geoids and Cap Sizes. Proceedings of the Scientific Assembly of the International Association of Geodesy-IAG97, Rio de Janeiro, Brazil, 1997.

Forsberg, R., K. Keller, S. Ekholm, C. S. Nielsen, C. C. Tscherning, N. Gundestrup, S. N. Madsen: Geodetic Ice Sheet Elevation Monitoring in Greenland for Global Change Research. Presented Symposium G8, European Geophysical Society General Assembly, Vienna, 1997.

Forsberg R., K. Keller, C.S. Nielsen, S. Ekholm, N.S. Gundestrup, C.S. Hvidberg, C.C. Tscherning, S.N. Madsen: Geodetic Ice Sheet Elevation and Ice Flow Monitoring in Greenland for Global Change Research. Poster U22A-5, AGU Fall meeting, San Francisco, Dec. 8-12 , 1997.

Hehl K., L. Bastos, S. Cunha, R. Forsberg, A. V. Olesen, A. Gidskehaug, U. Meyer, T. Boebel, L. Timmen, G. Xu, and M. Nesemann: Concepts and First Results of the AGMASCO Project. In: M.E. Cannon and G. Lechapelle (eds.). Proc. Int. Symp. on Kinematic Systems in Geodesy, Geomatics and Navigation, Banff, Canada, June 3-6, 1997, Publ.Univ. of Calgary, pp. 557-564, 1997.

Higgins, M., R Forsberg, A H W Kearsley: The effect of varying cap sizes on geoid computations - experineces with FFT’s and ring integration. Proceedings of the Scientific assembly of the International Association of Geodesy-IAG97, Rio de Janeiro, Brazil, in print, 1997.

Hvidberg, C.S., K. Keller, N.S. Gundestrup, C.C. Tscherning, and R. Forsberg: Mass balance and surface movement of the Greenland Ice Sheet at Summit, Central Greenland. Geophysical Research Letters, Vol. 24, No. 18, 2307-2310, 1997.

Joughin, I, M.A. Fahnestock, S. Ekholm, and R. Kwok: Balance velocites of the Greenland ice sheet. Geophys. Rev. Lett., 24, 3045-3048, 1997.

Kearsley, A. H. W., R Forsberg, A Olesen, L Bastos. K Hehl, U Meyer, A Gidskehaug: Airborne Gravimetry used in Precise Geoid Computations by Ring Integration. Journal of Geodesy, 1997.

Keller, K., R. Forsberg, C.S. Nielsen: Kinematic GPS for Ice Sheet Monitoring and SAR Interferometry in Greenland. In M.E. Cannon & G. Lachapelle, eds., Proceedings of the International Symposium on Kinematic Systems in Geodesy, Geomatics and Navigation, Banff, Canada, June 3-6 1997. Publ. KIS97, University of Calgary, pp. 525-528, 1997.

Keller, K., R. Forsberg, C.S. Nielsen: Airborne and Surface Kinematic GPS for Height Determination of the Greenland Ice Sheet. Poster G11B-7, AGU Fall meeting, San Francisco, Dec. 8-12 , 1997.

Kirby, J., and R. Forsberg: A comparison of techniques for the integration of satellite altimeter and surface gravity data for geoid determination. Proceedings of the Scientific assembly of the International Association of Geodesy-IAG97, Rio de Janeiro, Brazil, 1997.

Knudsen, P., and O. B. Andersen: Improved Recovery of the Global Marine Gravity Field from the GEOSAT and the ERS-1 Geodetic Mission. In: J.Segawa et al. (Eds.), Gravity, Geoid and Marine Geodesy, IAG Symposia, Springer-Verlag, Berlin, 429-436, 1997.

Knudsen, P., and O. B. Andersen: Global marine gravity and mean sea surface from multi mission satellite altimetry. Proceedings of the Scientific assembly of the International Association of Geodesy-IAG97, Rio de Janeiro, Brazil, 1997.

Knudsen, P., and O. B. Andersen: Regional characteristics of sea level and sea surface temperature trends from satellite. In: Proceedings of Monitoring the oceans in the 2000s: and integrated approach, Biarritz, France, october, 1997.

Knudsen, P., and O. B. Andersen: Sea level and sea surface temperature changes from satellites. Presented, EGS XXII General Assembly, Vienna, may, 1997.

Knudsen, P., O. B. Andersen, and T. Knudsen: Annual cycles of ERS-1 altimetric sea surface height data and atsr sea surface temperature data. Proceedings of 3rd ERS symposium, Florence, journal and CD version, march, 1997.

Knudsen, P., and O. B. Andersen: Improved recovery of the marine gravity field from combining the ERS-1 with the Geosat geodetic mission altimetry. Proceedings of 3rd ERS symposium, Florence, march, 1997.

Knudsen, P., and O. B. Andersen: Improved recovery of the marine gravity field from combining the ERS-1 with the Geosat geodetic mission. Presented, EGS XXII General Assembly, Vienna, may 1997.

Knudsen, P., and O. B. Andersen: Sea level variations and sea surface temperature changs from satellites. Presented AGU spring meeting, Baltimore, may, 1997.

Knudsen, P., O.B. Andersen, T. Knudsen: Annual Cycles of ATSR Sea Surface Temperature data and TOPEX/POSEIDON Sea Surface Height data. AVISO, Newsletter 5 CNES, april, 1997.

Knudsen, T.: Adding {GIS} functionality to specialized analysis programs for remote sensing data: Gravsoft and the Busstop project" Proceedings, EARSeL symposium: "Future Trends in Remote Sensing", Rotterdam, The Netherlands, A. A. Balkema (ed.), 1997.

Knudsen, T., and J. Brandt: GIS and high resolution atmospheric modelling for corrections of sea surface observations from the TOPEX/POSEIDON satellite altimeter. Proceedings, EARSeL symposium: "Future Trends in Remote Sensing", Rotterdam, The Netherlands, A. A. Balkema (ed.), 1997.

Nielsen, C.S.; R. Forsberg; K. Keller and J.J. Mohr: Merging of Elevations from SAR Interferometry, Satellite Altimetry, GPS and Laser Altimetry in Greenland, Proc. 3rd Scientific ERS Symposium, ESA SP-414 Vol. 1, p. 415-420, 1997.

Nielsen, C.S., R. Forsberg, K. Keller and J.J. Mohr: Merging of Elevations from SAR Interferometry, Satellite Altimetry, GPS and Laser Altimetry in Greenland. Proc. 3rd Scientific ERS Symposium, Florence, Italy, 1997.

Nielsen, C. S., R. Forsberg, K. Keller: Height Determination of a Local Greenland Ice Cap for Climate Monitoring. Presented Symposium G5, European Geophysical Society General Assembly, Vienna, 1997.

Nielsen, C.S., R. Forsberg, S. Ekholm and J.J. Mohr: SAR Interferometry for Improved Terrain Corrections in Surface and Airborne Gravimetry. Proc. Scientific Assembly of the IAG 1997, Rio de Janeiro, Brazil, 1997.

Olesen A V, R Forsberg, A Gidskehaug: LaCoste & Romberg gravity meter error models for airborne gravimetry. Presented, EGS meeting, Vienna, Austria, April 21-25, 1997.

Olesen A V, R Forsberg, A Gidskehaug: Airborne gravimetry using the LaCoste & Romberg gravimeter - an error analysis. In: M.E. Cannon and G. Lechapelle (eds.). Proc. Int. Symp. on Kinematic Systems in Geodesy, Geomatics and Navigation, Banff, Canada, June 3-6, 1997, Publ.Univ. of Calgary, pp. 613-618, 1997.

Poder, K., and K. Engsager: Some Conformal Mappings and Transformations for Geodesy and Topographic Cartography. Publ. of National Survey and Cadastre, Denmark, 4.series, vol. 6, in print, 1997.

Rignot, E., S.P. Gogineni, W.B. Krabill, and S. Ekholm: North and northeast Greenland discharge from satellite radar interferometry. Science, 272, 934-937, 1997.

Shum, C. K., P. L. Woodworth, O. B. Andersen, G. Egbert, O. Francis, C. King, S. Klosko, C. Le Provost, X. Li, J. Molines, M. Parke, R. Ray, M. Schlax, D. Stammer, C. Tierney, P. Vincent, and C. Wunch: Accuracy assesment of recent ocean tide models, J. Geophys. Res., 1997 .

Smith, A. J. E. and O. B. Andersen: Errors in recent ocean tide models: origin and cause. In: Tidal science, Eds R. Ray and P. L. Woodworth, Prog. in Oceanography, 1997.

Strykowski, G.: Formulation of the mathematical frame of the joint gravimetric-seismic modelling problem based on analysis of regionally distributed borehole data. Proc. Intern. Symp.on Gravity, Geoid and Marine Geodesy, sep 1996, Tokyo, Springer Verlag, pp. 360-367, 1997.

Strykowski, G.: Experiences with a Detailed Estimation of the Mass Density Contrasts and of the Regional Gravity Field using Geometrical Information from Seismograms. Accepted for publication Proc. Symp. EGS1 of 22nd General Assembly of EGS, Vienna, Austria, 1997.

Strykowski, G.: Geoid and Mass Density - Why and How? Accepted for publication Proc. Symp. 2, Scientific Assembly of IAG, Rio de Janeiro, Brazil, Sept. 3-9, 1997.

Strykowski, G.: Elements of the Joint Gravimetric-Seismic Modelling - Coupling the Available Information. Proc. Interdisciplinary Inversion Workshop 5, Department of Earth Sciences, Univ. of Aarhus, Denmark, Sept. 24, pp. 24-30, 1997.

Strykowski, G. and R. Forsberg: Operational Merging of Satellite, Airborne and Surface Gravity Data by Draping Techniques.Proc. Symp. 2, Scientific Assembly of IAG, Rio de Janeiro, Brazil, Sept. 3-9, 1997.

Timmen L, L Bastos, R Forsberg, A Gidskehaug, K Hehl, U Meyer, A V Olesen: Airborne Geoid Mapping System for Coastal Oceanography (AGMASCO). Presented, AGU fall meeting, San Francisco, December 8-12, 1997.

Tscherning, C. C., F. Rubek, R. Forsberg: Combining Airborne and Ground Gravity Data using Collocation. Proceedings of the Scientific assembly of the International Association of Geodesy-IAG97, Rio de Janeiro, Brazil, 1997.

Tziavos, I. N., R. Forsberg, M. G. Sideris, J. Li, V. Andritsanos: A comparison of satellite altimetry methods for recovery of ravity field anomalies. Proceedings of the Scientific Assembly of the International Association of Geodesy-IAG97, Rio de Janeiro, Brazil, 1997.

Tziavos, I. N., M. G. Sideris, R. Forsberg: Combined satellite altimetry and shipborne gravimetry data processing. Submitted to Journal of Marine Geodesy, 1997.

1998:

Andersen, O. B., and P. Knudsen: Multi-satellite Ocean tide modelling - the K1 constituent. In Tidal science, Eds R. Ray and P. L. Woodworth, Progress in Oceanography, Vol. 40 No 1-4, 197-216, 1997.

Andersen O. B., R. Forsberg, P. Knudsen, D. McAdoo and S. Laxon: Comparison of recent altimetric and shipborne gravity over ice-covered and ice-free polar seas. Proceedings of the Scientific Assembly of the International Association of Geodesy-IAG97, Rio de Janeiro, Brazil, IAG Symposia 119, 492 - 498, Springer Verlag, 1997.

Andersen, O. B.: Shallow water tides on the Northwest European shelf from TOPEX/POSEIDON altimetry. J. Geophys. Res., 1998.

Andersen, O. B.: Shallow water tidal determination from Altimetry - the M4 constituent. Submitted Proc. IGC-IgeC meeting, Trieste, Italy, Sep. 7-12, To be published in: Bolletino di geofisica teorica et applicata, 1998.

Andersen, O. B.: The inverse barometer correction and tides -revisited. Presented Joint TOPEX/POOSEIDON and Jason-1 SWT meeting, 13-15 oct., Keystone, Colorado, USA, 1998.

Andersen, O. B. and P. Knudsen: Global Marine Gravity Field from the ERS-1 and GEOSAT Geodetic Mission Altimetry. J. Geophys. Res., 103(C4), 8129-8137, 1998.

Andersen, O. B. and P. Knudsen: The KMS98 Global marine Gravity Field. Presented IGC -IGeC meeting, Trieste, 7-12 sept., 1998.

Andersen O. B., P. Knudsen, S. Kenyon and R. Trimmer: Marine gravity field around Greenland from various sources. Intercomparisons and recent improvements. Presented: Airborne Gravity and the Polar Gravity field, Kangalussuaq, Greenland 2-4 June, 1998.

Andersen O. B., P. Knudsen, S. Kenyon and R. Trimmer: Recent improvement in the KMS Global marine Gravity Field. Proceedings of the IGC -IGeC meeting, Bollettino di geofisica teorica ed applicata, Trieste, 7-12 sept., submitted, 1998.

Andersen, O. B., N. L. Bindoff, and R. Coleman: Global characteristics of low frequency sea level variability using spherical harmonic functions and wavelets analysis. Presented Joint TOPEX/POOSEIDON and Jason-1 SWT meeting, 13-15 oct., Keystone, Colorado, USA, 1998.

Andersen O. B., R. Forsberg, P. Knudsen, D. McAdoo and S. Laxon: Comparison of recent altimetric and shipborne gravity over ice-covered and ice-free polar seas. In "Geodesy on the Move, Gravity, geoid, geodynamics and Antarctica", Proceedings IAG scientific assembly, Rio de janeiro, sept 3-9 1997, Forsberg, Feissel and Dietrich (eds.), IAG symposia 119, 492 -498, Springer, Berlin,, 1998.

Arabelos, D. & C.C.Tscherning: Calibration of satellite gradiometer data

aided by ground gravity data. Journal of Geodesy, Vol. 12, no. 11,

pp. 617 - 625, 1998.

Bamber, J.L., S. Ekholm, W. Krabill: The accuracy of satellite radar altimeter data over the Greenland ice sheet determined from airborne laser data. Geophys. Res. Lett., vol. 25, 16, 3177-3180, 1998.

Borre, Kai: Block Elimination and Weight Matrices. Presented at the Hotine-Marussi Symposium, Trento, 1998..

Brandt, J., and T. Knudsen: Integrating GIS and external tools for spatio-temporal analysis of time series of remote sensing data Proceedings, EARSeL symposium: "Future Trends in Remote Sensing", Rotterdam, The Netherlands, A. A. Balkema, pp. 117-124, 1998.

Church, J. A., O. B. Andersen, N. White, and R. Coleman: Energy budgets from the TOPEX/POSEIDON global tide models. Presented Joint TOPEX/POOSEIDON and Jason-1 SWT meeting, 13-15 oct., Keystone, Colorado, USA, 1998.

Coleman, R., and O. B. Andersen: Global characteristics of low frequency sea level variability using spherical harmonic functions. Presented Western Pacific Geophysical Meeting, Taipei, Taiwan, July, 21 -24, 1998.

Dahl, O., and R. Forsberg: Geoid models of the Sognefjord Area. Journal of Geodesy, vol. 72, 9, pp. 547-556, 1998.

Dahl, O., and R. Forsberg: Different ways to handle topography in practical geoid determination. Physics and Chemistry of the Earth, 1998.

Ekholm, S.: Determination of Greenland Surface Topography from Satellite Altimetry and Other Elevation Data. Technical report no. 9, Kort & Matrikelstyrelsen, 1998.

Ekholm, S., K. Keller, J.L. Bamber, S.P. Gogineni: Unusual surface morphology from digital elevation models of the Greenland ice sheet. Geophys. Res. Lett., vol. 25, 19, 3623-3626, 1998.

Engsager, K.: Integration of Satellite Data in Local Geodetic Networks, Implementation and Numerical Analysis. Publ. of National Survey and Cadastre, Denmark, 4.series, vol. 5, 77 pp., 1998.

Engsager K: Testing of a priory mean errors of Geodetic Observations. Proceedings of the 13th General Meeting of the Nordic Geodetic Commission, Gävle, Sweden, in print, 1998.

Forsberg R.: Geoid tayloring to GPS - with example of a 1 cm geoid of Danmark. Accepted for publication Proc. 2nd Continental Workshop on the Geoid in Europe, Budapest, Hungary, March 10-14, Vermeer M. (ed.), Reports of the Finnish Geodetic Institute, 98:4, pp. 191-198, 1998.

Forsberg, R.: The use of spectral techniques in gravity field modelling: trends and perspectives. Physics and Chemistry of the Earth, Vol. 23, No. 1, 1998.

Forsberg, R., S. Kenyon, J. Brozena: The Greenland gravity project. Pres. Int. Workshop on Airobnre Gravity and the Polar Gravity Field, Kangerlussuaq, Greenland, June 1998.

Forsberg, R., M. Feissl, R. Dietrich (eds.): Geodesy on the Move -Gravity, Geoid, Geodynamics and Antarctica. IAG symposia volume 119, Springer Verlag, 1998.

Forsberg R., A.V. Olesen, L. Timmen, G. Xu, L. Bastos, K. Hehl, D. Solheim: Airborne gravity in Skagerrak and elsewhere: the AGMASCO projekt and a nordic outlook.

Proc. NKG meeting Gävle, May 1998, 1998.

Forsberg R., A.V. Olesen, L. Timmen, M. Nesemann, G. Xu, U. Meyer, T. Boebel, L. Bastos, S. Cunha, A. Gidskehaug, K. Hehl: Geoid determination by airborne gravimetry -the AGMASCO project. Proc. 2nd Joint Meeting of the International Gravity Commision and the International Geoid Commission, Trieste, Italy, September 7-12, 1998.

Forsberg, R., A. Olesen, L. Bastos, A. Giskehaug, K. Hehl, T. Boebel, U. Meyer, M. Nesemann, G. Xu, L. Timmen: Geoid and Sea-surface Topography Determination by Airborne Techniques. Presented EGS General Assembly, Nice, 1998.

Forsberg R. and J. Taagholt: Danish research initiative in the Arctic Ocean North of Greenland. White paper, Proc. SCICEX workshop, Washington DC, 1998.

Harris, P., O. B. Andersen, and R. Coleman: Tidal induced sediment transportation around Australia. Presented Australian Sedimentological Society, Townville, June 20-25, 1998.

Jensen, A.B.O. and F.B. Madsen: A New Three Dimensional Reference Network in Denmark. Proceedings 13th General Meeting of the Nordic Geodetic Commission, to be published by Lantmäteriverket, Gävle, Sweden, in press, 1998.

Johannesen, J.A., G.Balmino, C.Le Provost, R.Rummel, H.Suenkel,

C.C.Tscherning, P.Woodworth, M.Ahuirre, A.Tobias, H.Rebhan, D.Lamarre,

and P.Silvestrin: The Gravity field and steady-state Ocean

Explorer mission. Submitted GEWEX NEWS, Sept. 1998.

Kearsley, A. H. W., R. Forsberg, A. Olesen, L. Bastos, K. Hehl, U. Meyer, A. Gidskehaug: Airborne gravimetry used in precise geoid computations by ring integration. Journal of Geodesy, 72, pp 600-605, 1998.

Knudsen, P.: Global high resolution mean sea surface from multi mission satellite altimetry. Physics and Chemistry of the Earth, Elsevier Science, Berlin, 1998.

Knudsen, P., and O. B. Andersen: A global high resolution mean sea surface from multi mission satellite altimetry. Presented Joint TOPEX/POOSEIDON and Jason-1 SWT meeting, 13-15 oct., Keystone, Colorado, USA, 1998.

Knudsen, P., and O. B. Andersen: Global marine gravity and mean sea surface from multimission satellite altimetry. In "Geodesy on the Move, Gravity, geoid, geodynamics and Antarctica", Proceedings IAG scientific assembly, Rio de janeiro, sept 3-9 1997, Eds, Forsberg, Feissel and Dietrich., IAG symposia, 119, 132-138, Springer, Berlin, 1998.

Knudsen, P., O. B. Andersen, T. Knudsen and O. Leeuwenburgh: Onging TOPEX/POSEIDON extended mission research at the National Survey and Cadastre -Denmark. AVISO, Newsletter 6, CNES, April, 63 -64, 1998.

Knudsen, T.: Busstop-a spatio-temporal information system. Ph.d.-thesis, University of Copenhagen, 224 pp., 1998.

Knudsen, T.: Adding GIS functionality to specialized analysis programs for remote sensing data: Gravsoft and the Busstop project. In: Gudmandsen, P. (ed), 1998: Future Trends in Remote Sensing, Rotterdam, A.A.Balkema Publ., pp. 125-132, 1998.

Knudsen, T.: Busstop-an integrated system for handling, analysis and visualization of ocean data. Physics and Chemistry of the Earth, 1998.

Knudsen T., and A.V. Olesen: A GIS based strategy for quality control of gravimetry. Submitted to Bulletin of the International Geoid Service, 1998.

Leeuwenburgh O., O.B.Andersen and V.Huess: Seasonal tide variations from tide gauges and altimetry. Physics and Chemistry of the Earth, 1998.

Moreaux, G., C.C.Tscherning & F.Sanso': Approximation of Harmonic

Covariance Functions by non Harmonic Locally Supported Ones. Prepared

for the Hotine-Marussi Symp., Trento 1998

Nielsen, C.S., R. Forsberg, S. Ekholm and J.J. Mohr: SAR Interferometry for Improved Terrain Corrections in Surface and Airborne Gravimetry. Proc. IAG Scientific Assembly, Sep. 3-9, 1997, Rio de Janeiro, Brazil, In: Forsberg, R., M. Feissel & R. Dietrich (Eds.): Geodesy on the Move; Gravity, Geoid, Geodynamics and Antarctica, International Association of Geodesy Symposia, Volume 119, p. 529 + 46-50, Springer Verlag, 1998.

Nielsen, C.S., R. Forsberg, K. Keller and J.J. Mohr: Topography and Surface Flow of the Geikie Ice Cap Derived from SAR Interferometry, Laser Altimetry and GPS Measurements Presented EGS XXIII General Assembly, Apr. 20 - 24, 1998, Nice, France, 1998.

Nielsen, C.S., R. Forsberg, K. Keller and J.J. Mohr: SAR Interferometry for Digital Elevation Models in Greenland. Presented IAG Workshop on Airborne Gravity and the Polar Gravity Field, June 2-4, Kangerlussuaq, Greenland, 1998.

Nielsen, C.S., R. Forsberg, K. Keller and J.J. Mohr: Merging of Data from SAR Interferometry, Laser Altimetry and GPS for Determination of Ice Cap Topography and Surface Flow in Greenland. Presented AGU 1998 Fall Meeting, December 6-10, 1998, San Francisco, Abstract in EOS, Transactions, American Geophysical Union, 1998 Fall Meeting, Vol. 79, No. 45, November 10,

Supplement 1998.

Olesen A.V., R. Forsberg, L. Bastos, A. Gidskehaug, K. Hehl, U. Meyer, L.

Timmen: High-resolution airborne gravity survey of Skagerrak. Poster, XXIII EGS General Assembly, Nice, France, April 20-24, 1998.

Olesen A V, R Forsberg, A Gidskehaug, L Bastos, K Hehl, U Meyer, L

Timmen: Error models for a LaCoste & Romberg S gravimeter in an airborne application. Presented, Airborne Gravity and the Polar Gravity Field, Kangerlussuaq, Greenland, June 2-4, 1998.

Poder, K., and K. Engsager: Some Conformal Mappings and Transformations for Geodesy and Topographic Cartography. Publ. of National Survey and Cadastre, Denmark, 4.series, vol. 6, pp. 63, 1998.

Rubek, F.: Downward continuation of airborne gravity. Presented at: Workshop on Airborne Gravity and the Polar Gravity Field, June 2-4, Kangerlussuaq, Greenland, 1998.

Rubek, F. and R. Forsberg: Gravity and GPS measurements in Greenland 1991-1997. Proceedings 13th General Meeting of the Nordic Geodetic Commission, to be published by Lantmäteriverket, Gävle, Sveden, in press, 1998.

Smith, A. J. E. and O. B. Andersen: Errors in recent ocean tide models: origin and cause. In: Tidal science, Eds R. Ray and P. L. Woodworth, Prog. in Oceanography, Vol. 40, 325 -336, 1997.

Strykowski, G.: Geoid and Mass Density - Why and How? Proc. IAG Scientific Assembly, Sep. 3-9, 1997, Rio de Janeiro, Brazil, In: Forsberg, R., M. Feissel & R. Dietrich (Eds.): Geodesy on the Move; Gravity, Geoid, Geodynamics and Antarctica, International Association of Geodesy Symposia, Volume 119, p. 237 - 242, Springer Verlag, 1997.

Strykowski, G.: Some technical details concerning a new method of gravimetric-seismic inversion. Accepted Proc. Symp. EGS3, EGS XXII General Assembly, April 20-24, 1998, Nice, France, Phys. Chem. Earth., vol. 23, pp. 845 - 856, 1998.

Strykowski G.: On the use of Mass Density in Geodesy and Solid Earth Geophysics - the advantages and the pitfalls. Lecture in Tuesday Lecture Series, Geodetic and Geophysical Research Institute of the Hungarian Academy of Science in Sopron, 1998.

Strykowski, G.: Geophysically Controlled Gravimetric-Seismic Inversion by Parts. Presented at The Second Interdisciplinary Inversion Conference.University of Copenhagen, Denmark, 12-14. AUG. 1998.

Strykowski G.: Modelling of the Source of the Silkeborg Gravity High from Gravity and Seismics. Presented Workshop on Lithosphere variation around the Sorgenfrei-Tornquist Zone, Kort & Matrikelstyrelsen, København, 1. DEC, 1998.

Strykowski G.: Joint gravimetric - seismic modelling , problems and perspectives. Lecture in Friday Lecture Series, Institute of Solid Earth Physics, University of Bergen, Norway, Dec. 4, 1998.

Strykowski, G. and O.C. Dahl: The geoid as an Equipotential Surface in a Sense of Newton's Integral - Ideas and Examples. Proceedings 2nd Continental Workshop on the Geoid in Europe, Budapest, Hungary, March 10-14, Vermeer M. and Adam J. (eds.), Reports of the Finnish Geodetic Institute, 98:4, 107-112, 1998.

Strykowski, G. and R. Forsberg: Operational Merging of Satellite, Airborne and Surface Gravity Data by Draping Techniques. Proc. IAG Scientific Assembly, Sep. 3-9, 1997, Rio de Janeiro, Brazil, In: Forsberg, R., M. Feissel & R. Dietrich (Eds.): Geodesy on the Move; Gravity, Geoid, Geodynamics and Antarctica, International Association of Geodesy Symposia, Volume 119, p. 243 - 248, Springer Verlag, 1998.

Strykowski, G. and R.Forsberg: Processing of marine gravity data off West Greenland 1997. Contract report for NUNAOIL A/S, Department of Geodynsmics, National Survey and Cadastre of Denmark, 1998.

Strykowski, G and R. Forsberg: Operational Merging of Satellite, Airborne and Surface Gravity Data by Draping Techniques. Presented Workshop on Airborne Gravity and the Polar Gravity Field, June 2-4, Kangerlussuaq, Greenland, 1998.

Strykowski G. and R. Forsberg: Surface Gravity Map of Denmark and the Adjacent Land Areas. Presented Workshop on Lithosphere variation around the Sorgenfrei-Tornquist Zone, Kort & Matrikelstyrelsen, København, 1. DEC, 1998.

Syndergaard, S., P.Hoeg, K.Mosegaard and C.C.Tscherning: Inversion

of GPS-occultation data for atmospheric profiling. Draft, Sept. 1998.

Thomsen, Henrik: Error Detection in GPS Observations by Means of Multi Process Models. Presented at the Hotine-Marussi Symposium, Trento, 1998. To appear in proceedings of the meeting.

Timmen, L., L. Bastos, T. Boebel, S. Cunha, R. Forsberg, A. Gidskehaug,

K. Hehl, U. Meyer, M. Nesemann, A. V. Olesen, F. Rubek, G. Xu: The European Airborne Geoid Mapping System for Coastal Oceanography (AGMASCO). In: Progress in Geodetic Science at GW 98, Proceedings of the Geodetic

Week 1998, University of Kaiserslautern, Germany, Shaker Verlag, Aachen, 1998.

Tscherning, C.C.: Evaluation of the EGM96, the EGG97 and the GEONZ97

(gravimetric) geoids in the North Sea Area. Bulletin of the IGeS,

Vol. 7, pp. 24 - 29, Milano, 1998.

Tscherning, C.C.: Construction of an-isotropic covariance-functions

using Riez-representers. Prepared for the Hotine-Marussi Symposium, Trento,

Sept. 1998. Submitted to Journal of Geodesy, 1998.

Tscherning, C.C., J.Nielsen, D.Arabelos, R.Haagmans, P.Knudsen, F.Sanso' &

H.Suenkel: Computer supported Cooperation - the future of the IAG

Information service and of cooperation within IAG. Science Services,

IAG Scentific Assembly, Rio de Janeiro, Sept. 1997, pp. 47 - 54, IAG 1998.

Tscherning, C.C., F.Rubek and R.Forsberg: Combining Airborne and ground

Gravity using Collocation. In: Forsberg,R., M.Feissel, R.Dietrich (Eds):

Geodesy on the Move. Proceeding IAG Scientific Assembly,

Rio de Janeiro, Sept. 1997 ,IAG Symp. Vol. 119, pp. 18-23, Springer V.,1998 .

Wang, G., Xu, G.: GPS - Theory, Practice and Software Development. Science Publishing House, Peking, (in Chinese), in print, 1998.

Woodworth, P.L., J.Johannesen, P. Le Grand, C. Le Provost, G.Balmino,

R.Rummel, R.Sabadini, H.Suenkel, C.C.Tscherning & P.Visser: Towards

the Definitive Space Gravity Mission. Int. WOCE Newsletter, No. 33, pp.

37 - 40, Dec. 1998.

Wybraniec, S., S. Zhou, R. Forsberg, M. Lee, E. Pershuc, H. Thybo, R. Forsberg, G. Demianov, S. Strakhov: A new look at the gravity field of Europe. Transactions (EOS), American Geophysical Union, September 1998.

Xu, G., Schwintzer, P., and Reigber, C.: KSGSoft - Kinematic/Static GPS Software - Software User Manual, (Version of 1998). Scientific Technical Report STR98/19, GeoForschungsZentrum (GFZ), Potsdam, 1998.