Smoothing the Gradiometric Observations Using Different Topographic–Isostatic Models: A Regional Case Study
In terrestrial and airborne gravity field determination the formulae for the gravitational potential and its first order derivatives have been used, while the second order derivatives are related to the analysis of upcoming satellite gravity gradiometry missions of GOCE type. Especially there, the reduction of topographic and isostatic effects is important to produce a smooth gravity field suitable for downward continuation. In this paper various isostatic models, namely the models of Airy–Heiskanen (A–H) and Pratt–Hayford (P–H), the combination of the Airy–Heiskanen model (land area) and the Pratt–Hayford model (ocean area), the first (H1) condensation model of Helmert as well as a crust density model are analyzed for a GOCE-like satellite orbit in two selected regions: Japan and central part of Europe. The different topographic–isostatic effects are compared with respect to the degree of smoothing of the measured satellite gradiometric data. The results of this paper can serve as a base for further investigations of the suitability of particular reduction models for downward continuation.
KeywordsSatellite gravity gradiometry isostatic models (Airy–Heiskanen Pratt–Hayford) first condensation model of Helmert crust density model.
The research presented in this paper has been partially supported by the Slovak national projects VEGA 1/0775/08 and APVV 0351–07.
- Bassin C, Laske G, Masters G (2000) The current limits of resolution for surface wave tomography in North America. EOS Trans Am Geophys Union 81:F897Google Scholar
- Janák J, Wild-Pfeiffer F (2010) Comparison of various topographic–isostatic effects in terms of smoothing gradiometric observations. In Mertikas S (ed) Proc. of IAG international symposium gravity, geoid and earth observation. IAG Symposia, vol 135. Springer, Berlin, pp 377–382Google Scholar
- Pavlis NK, Holmes SA, Kenyon SC, Factor JK (2008) An earth gravitational model to degree 2160 EGM2008. Geophysical Research Abstracts EGU 2008Google Scholar
- Wild-Pfeiffer F, Heck B (2008) Topographic and isostatic reductions for use in satellite gravity gradiometry. In: Xu P, Liu J, Dermanis A (eds) Proc. of the VI. Hotine-Marussi symposium. IAG proc., IAG symposia, vol 132. Springer, Berlin, pp 49–55Google Scholar