Abstract
The peculiar features of the Mediterranean Sea in terms of both gravity variations and geodynamic complexities resulted in a wide range of studies and research projects during the last decades focusing on the modeling of static and dynamic processes of this almost closed sea basin. The scope of the present study is twofold. The first part shall provide a synopsis of the data and methods used and the results achieved for geoid determination in the first phase of the GEOMED project (GEOid in the MEDiterranean) in the early 90s. The second part focuses on the recent activities and improvements of the continuation of the previous research in the framework of the GEOMED-2 project which is still an ongoing work. The collection of all available surface and satellite data towards the creation of improved gravity databases and the computation of marine geoid models are discussed. The crucial role of global geopotential models and digital topography and bathymetry is analyzed, focusing on the efficient modeling of the low and high frequencies of the gravity signal. The numerical methodology is discussed in the context of the available data sets and computer facilities over the duration of GEOMED. Finally, gravity databases and geoid models for the whole test area are presented and evaluated for both phases of the project. Some recommendations are also drawn along with a discussion on new methodological tools for the implementation of new data sources, targeting to the future improvement of gravity field over the Mediterranean Sea.
Similar content being viewed by others
References
Allan TD, Morelli C (1971) A geophysical study of the Mediterranean Sea. NATO Subcommittee on oceanographic research, Technical report no 55, p 141
Andersen OB, Knudsen P, Berry P (2010) The DNSC08GRA global marine gravity field from double retracked satellite altimetry. J Geod 84(3):191–199. https://doi.org/10.1007/s00190-009-0355-9
Andersen OB, Knudsen P, Kenyon S, Factor JK, Holms S (2017) Global gravity field from recent satellites (DTU15)—Arctic improvements. EAGE First Break 35(11):37–40
Andritsanos VD, Sideris MG, Tziavos IN (2001) Quasi-stationary sea surface topography estimation by the multiple input/output method. J Geod 75:216–226. https://doi.org/10.1007/s001900100169
Arabelos D, Tscherning CC (1988) Gravity field map** from satellite altimetry, sea gravimetry and bathymetry in the eastern Mediterranean. J Geophys Res 92:195–206
Arabelos D, Tziavos IN (1990) Sea surface heights in the Mediterranean Sea from Geosat altimeter data. J Geophys Res Oceans 95(C10):17947–17956
Arabelos D, Tziavos IN (1992) Geoid map** in the Mediterranean Sea using heterogeneous data. In: Mare Nostrum—Geomed report 2, Milano, Italy
Arabelos D, Tziavos IN (1996) Combination of ERS-1 and TOPEX altimetry for precise geoid and gravity recovery in the Mediterranean Sea. Geophys J Int 125:285–302
Arabelos D, Spatalas SD, Tziavos IN (1992) Altimeter data from ERS-1 in the Mediterranean Sea. In: Mare Nostrum—Geomed report 2, Milano, Italy
Arabelos D, Barzaghi R, Sansò F, Sona G (1994) The gravimetric geoid and the SST in the eastern Mediterranean. In: Mare Nostrum—Geomed report 4, Thessaloniki, Greece
Barzaghi R et al (2014) Estimating geoid and sea surface topography in the Mediterranean Sea (the GEOMED2 project). In: IGFS2014 conference, Shanghai, China
Barzaghi R et al (2018a) GEOMED2: high-resolution geoid in the Mediterranean. In: Freymueller J, Sánchez L (eds) International symposium on advancing geodesy in a changing world. International Association of Geodesy Symposia, vol 149. Springer, Cham
Barzaghi R et al (2018b) Geoid and DOT in the Mediterranean area: the GEOMED2 project. In: GGHS2018 conference, Copenhagen, Denmark
Barzaghi R, Brovelli M, Sansò F, Tscherning CC (1992) Geoid computation in the Mediterranean area. In: Mare Nostrum—Geomed report 2, Milano, Italy
Barzaghi R, Tselfes N, Tziavos IN, Vergos GS (2009a) Geoid and high resolution sea surface topography modelling in the Mediterranean from gravimetry, altimetry and GOCE data: evaluation by simulation. J Geod 83:751–772. https://doi.org/10.1007/s00190-008-0292-z
Barzaghi R, Tselfes N, Tziavos IN, Vergos GS (2009b) Combination of gravimetry, altimetry and GOCE data for geoid determination in the Mediterranean: evaluation by simulation. In: Sideris MG (ed) Observing our changing earth. International Association of Geodesy Symposia, vol 133. Springer, Cham
Becker JJ et al (2009) Global bathymetry and elevation data at 30ʺ resolution: SRTM30_PLUS. Mar Geod 32(4):355–371. https://doi.org/10.1080/01490410903297766
Bottoni GP, Barzaghi R (1993) Fast collocation. Bull Géod 67:119–126
Brovelli M, Sansò F (1992) The Geomed project: the state of the art. In: Mare Nostrum—Geomed report 2, Milano, Italy
Bruinsma S et al (2017) GEOMED2: Gravimetric versus combined geoid model. In: IAG-IASPEI conference, Kobe, Japan
Farr TG et al (2007) The shuttle radar topography mission. Rev Geophys 45:04. https://doi.org/10.1029/2005RG000183
Forsberg R (1984) A study of terrain reductions, density anomalies and geophysical inversion methods in gravity field modeling. Department of Geodetic Science and Surveying, Ohio State University, Report no 355, p 120
Forsberg R, Sideris MG (1993) Geoid computations by the multiband spherical FFT approach. Manuscr Geod 18:82–90
Forsberg R, Tscherning CC (1981) The use of height data in gravity field approximation by collocation. J Geophys Res 86(B9):7843–7854
Forsberg R, Tscherning CC (2008) An overview manual for the GRAVSOFT Geodetic Gravity Field Modelling Programs, 2nd edn
Förste C et al (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 Serv. https://doi.org/10.5880/icgem.2015.1
Geophysical data report of the Eastern Mediterranean Sea: RRS Shackleton cruises 3/72, 5/72, 1/74, July 28–Sept. 1, 1972, Oct. 4–Nov. 9, 1972, May 9–June 29, 1974 (1974) University of Cambridge, Department of Geodesy and Geophysics, The University of Cambridge
Haagmans R, de Min E, Van Gelderen M (1993) Fast evaluation of convolution integrals on the sphere using 1D FFT, and a comparison with existing methods for stokes’ integral. Manuscr Geod 18:227–241
Hirt C, Kuhn M (2014) Band-limited topographic mass distribution generates full-spectrum gravity field: gravity forward modeling in the spectral and spatial domain revisited. J Geophys Res Solid Earth 119:3646–3661
Hirt C, Kuhn M, Claessens S, Pail R, Seitz K, Gruber T (2014) Study of the Earth’s short-scale gravity field using the ERTM2160 gravity model. Comput Geosci 73:71–80
Hirt C, Rexer M, Claessens S, Rummel R (2017) The relation between degree-2160 spectral models of Earth’s gravitational and topographic potential—a guide on global correlation measures and their dependency on approximation effects. J Geod 91(10):1179–1205. https://doi.org/10.1007/s00190-017-1016-z
Lequentrec-Lalancette MF, Rouxel D (2010) Comparison of a marine gravimetric geoid and global satellite model in the Atlantic Ocean. In: Lacoste-Francis H (ed) Proceedings of ESA living planet symposium, held on 28 June–2 July 2010 at Bergen in Norway. ISBN 978-92-9221-250-6. ESA SP-686, 2010, ID.499
Lequentrec-Lalancette MF, Salaün C, Bonvalot S, Rouxel D, Bruinsma S (2016) Exploitation of marine gravity measurements of the Mediterranean in the validation of global gravity field models. In: Freimueller JT, Sanchez L (eds) Earth and Environmental Sciences for Future Generations, International Association of Geodesy Symposia, vol 147, Springer, Cham
MARE NOSTRUM—GEOMED (1992a) Geomed report 1, Milano, Italy
MARE NOSTRUM—GEOMED (1992b) Geomed report 2, Madrid, Spain
MARE NOSTRUM—GEOMED (1993) Geomed report 3, Milano, Italy
MARE NOSTRUM—GEOMED (1994) Geomed report 4, Thessaloniki, Greece
Mertikas SP, Daskalakis A, Tziavos IN, Andersen OB, Vergos GS, Tripolitsiotis A, Zervakis V, Frantzis X, Partsinevelos P (2013) Altimetry, bathymetry and geoid variations at the Gavdos permanent Cal/Val facility. Adv Space Res 51:1418–1437
Migliaccio F, Reguzzoni M, Sansò F (2004) Space-wise approach to satellite gravity field determination in the presence of colored noise. J Geod 78:304–313
Morelli C, Pisani M, Gantar C (1975) Geophysical studies in the Aegean Sea and in the eastern Mediterranean. Boll Geofis teor appli XVIII, pp 127–168
NOAA (1988) Data announcement 88-MGG-02. Digital relief of the surface of the earth, NOAA, National Geophysical Data Center, Boulder
Pail et al (2011) First GOCE gravity field models derived by three different approaches. J Geod 85:819–843
Pavlis N, Holmes S, Kenyon S, Factor J (2012) The development and evaluation of the earth gravitational model 2008 (EGM2008). J Geophys Res Solid Earth 117:2633–B04406. https://doi.org/10.1029/2011JB008916
Rapp RH, Cruz JY (1986) Spherical harmonic expansions of the earth’s gravitational potential to degree 360 using 30 arc-min anomalies. Report 376, Dept of Geod Sci, Ohio State University, Columbus
Rio MH, Pascual A, Poulain PM, Menna M, Barcelo B, Tintoré J (2014) Computation of a new mean dynamic topography for the Mediterranean Sea from model outputs, altimeter measurements and oceanographic in-situ data. Ocean Sci 10(4):731. https://doi.org/10.5194/osd-11-655-2014
Sandwell DT, Müller RD, Smith WHF, Garcia E, Francis R (2014) New global marine gravity model from CryoSat-2 and Jason-1 reveals buried tectonic structure. Science 346(6205):65–67. https://doi.org/10.1126/science.1258213
Sansò F, Sideris MG (1997) On the similarities and differences between systems theory and least-squares collocation in physical geodesy. Boll Geod Sci Aff LV I(2):173–206
Sansò F, Sideris MG (2013) Geoid determination-Theory and methods. Lecture notes in earth system sciences, vol 110, Springer, Berlin
Sansò F, Venuti G, Tziavos IN, Vergos GS, Grigoriadis VN (2008) Geoid and sea surface topography from satellite and ground data in the Mediterranean region: A review and new proposals. Boll Geod Sci Aff 27(3):157–201
Sideris MG (2013) Geoid determination by FFT techniques. In: Sansò F, Sideris MG (eds) Geoid determination. Lecture notes in earth system sciences, vol 110, Springer, Berlin
Tscherning CC (1993) An experiment to determine gravity from geoid heights in Turkey. In: Mare Nostrum—Geomed report 3, Milano, Italy
Tscherning CC (2013) Geoid determination by 3D least-squares collocation. In: Sansò F, Sideris MG (eds) Geoid determination-Theory and methods. Lecture notes in earth system sciences, vol 110, Springer, Berlin
Tziavos IN, Sideris MG (2013) Topographic reductions in gravity and geoid modeling. In: Sansò F and Sideris MG (eds) Geoid determination-theory and methods. Lecture notes in earth system sciences, vol 110, Springer, Berlin
Tziavos IN, Vergos GS, Grigoriadis VN (2010) Investigation of topographic reductions and aliasing effects on gravity and the geoid over Greece based on various digital terrain models. Surv Geophys 31:23–67
Tziavos IN, Vergos GS, Mertikas SP, Daskalakis A, Grigoriadis VN, Tripolitsiotis A (2013) The contribution of local gravimetric geoid models to the calibration of satellite altimetry data and an outlook of the latest GOCE GGM performance in Gavdos. Adv Space Res 51:1502–1522
Vergos GS, Tziavos IN, Andritsanos VD (2005) Gravity data base generation and geoid model estimation using heterogeneous data. In: Jekeli C, Bastos L Fernandes J (eds) Gravity, geoid and space missions. International Association of Geodesy Symposia, vol 129. Springer, Cham
Vergos GS, Tziavos IN, Andritsanos VD (2005b) On the determination of marine geoid models by least-squares collocation and spectral methods using heterogeneous data. In: Sansò F (ed) A window on the future of geodesy. International Association of Geodesy Symposia, vol 128. Springer, Cham
Wessel P, Smith WHF, Scharroo R, Luis JF, Wobbe F (2013) Generic map** tools: improved version released. EOS Trans AGU 94:409–410
Wong L, Gore R (1969) Accuracy of geoidal heights from modified Stokes kernels. Geophys J R Astron Soc 18:81–91
Acknowledgements
I would like to express my sincere thanks to Profs. Fernando Sansò and Riccardo Barzaghi, Principal Investigators of GEOMED-1 and GEOMED-2 projects, respectively, who invited me to give a lecture for GEOMED in the workshop "Earth’s Gravity field and Earth sciences" held in the Accademia Nazionale dei Lincei in Rome, on March 22nd, 2019. This lecture formed the basis of the present paper. Many thanks are due to Prof. Vergos who provided redrawn versions of some figures of the paper. These figures were produced by the Generic Map** Tools v5.3.1 software (Wessel et al. 2013).
Author information
Authors and Affiliations
Corresponding author
Ethics declarations
Conflict of interest
The author declares that there is no conflict of interest.
Ethical approval
The paper is in compliance with the ethical guidelines of the journal. Cited researches and figures refer to studies published in the framework of the GEOMED project.
Additional information
Publisher's Note
Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
Rights and permissions
About this article
Cite this article
Tziavos, I.N. Gravity and geoid in the Mediterranean Sea: the GEOMED project. Rend. Fis. Acc. Lincei 31 (Suppl 1), 83–97 (2020). https://doi.org/10.1007/s12210-020-00880-3
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s12210-020-00880-3