Abstract
An airborne gravity survey of Nepal was carried out December 2010 in a cooperation between DTU-Space, Nepal Survey Department, and NGA, USA. The entire country was flown with survey lines spaced 6 nm with a Beech King Air aircraft, with a varying flight altitude from 4 to 10 km. The survey operations were a major challenge due to excessive jet streams at altitude as well as occasional excessive mountain waves. Despite the large 400 mGal + range of gravity anomaly changes from the Indian plains to the Tibetan Plateau, results appear accurate to few mGal, with proper evaluation from cross-overs complicated by the high varying flight altitudes. Using a downward continuation scheme based on blocked least-squares collocation, a new geoid of Nepal was computed by Fourier methods. The new geoid shows large changes to EGM08, illustrating the impact of the new data. The new geoid is compared to limited GPS-levelling data as well as recent GPS-heights of Mt. Everest, and the new data also provide an independent validation of GOCE gravity field models at the local ∼100 km resolution scale.
This is a preview of subscription content, log in via an institution to check access.
Access this chapter
Tax calculation will be finalised at checkout
Purchases are for personal use only
References
Chen Y et al (2006) Progress in technology for the 2005 height determination of Qomolangma Feng (Mt. Everest). Sci China Ser D Earth Sci 49
Forsberg R (1984) A study of terrain reductions, density anomalies and geophysical inversion methods in gravity field modelling. Reports of the Department of Geodetic Science and Surveying, no. 355. The Ohio State University, Columbus
Forsberg R (1987) A new covariance model for inertial gravimetry and gradiometry. J Geophys Res 92:1305–1310
Forsberg R (2002) Downward continuation of airborne gravity—an Arctic case story. In: Proceedings IGGC meeting, Thessaloniki, pp 51–56
Forsberg R, Sideris MG (1989) On topographic effects in gravity field approximation. In: Kejlsø, Poder, Tscherning (eds) Festschrift to Torben Krarup, Geodætisk Institut Meddelelse no. 58, pp 129–148
Forsberg R, Featherstone W (1998) Geoids and cap sizes. In: Geodesy on the move—gravity, geoid, geodynamics and Antarctica. IAG symposia, vol 119. Springer, Berlin, pp 194–200
Forsberg R, Sideris MG (1993) Geoid computations by the multi-band spherical FFT approach. Manuscr Geodaetica 18:82–90
Heiskanen W, Moritz H (1967) Physical geodesy. Freeman
Keller W, Hirsch M (1992) Downward continuation versus free-air reduction in airborne gravimetry. In: Geodesy and physics of the Earth. IAG symposia, vol 112. Springer, Berlin, pp 260–266
Li Y (2000) Airborne gravimetry for geoid determination. Ph.D. Thesis. Department of Geomatics Engineering, University of Calgary, 161 pp
Olesen AV (2003) Improved airborne scalar gravimetry for regional gravity field mapping and geoid determination. Technical Report no. 24. Kort og Matrikelstyrelsen, Copenhagen
Pail R, Goiginger H, Mayrhofer R, Schuh W-D, Brockmann JM, Krasbutter I, Höck E, Fecher T (2010) Global gravity field model derived from orbit and gradiometry data applying the time-wise method. In: Proceedings of ESA living planet symposium, Bergen, ESA SP-686, 28 June–2 July 2010
Pavlis N, Holmes S, Kenyon S, Factor J (2008) An Earth gravitational model to degree 2160: EGM08. In: EGU general assembly 2008, Vienna, April 2008
Tscherning CC, Rapp RH (1974) Closed covariance expressions for gravity anomalies, geoid undulations and deflections of the vertical implied by degree-variance models. Rep. 208. Department of Geodetic Science, Ohio State University, Columbus
Acknowledgements
We thank the COWI pilots for professional flight operations under the challenging conditions, and the Nepalese Army for allowing access to Kathmandu military airport facilities. We also thank F. Palmeri and G. Poretti, OGS and CNR, Italy, for providing additional surface gravity data in Nepal to aid in the geoid determination. Economic support for the Nepal airborne gravity project was proved by NGA and DTU.
Author information
Authors and Affiliations
Corresponding author
Editor information
Editors and Affiliations
Rights and permissions
Copyright information
© 2014 Springer-Verlag Berlin Heidelberg
About this paper
Cite this paper
Forsberg, R., Olesen, A.V., Einarsson, I., Manandhar, N., Shreshta, K. (2014). Geoid of Nepal from Airborne Gravity Survey. In: Rizos, C., Willis, P. (eds) Earth on the Edge: Science for a Sustainable Planet. International Association of Geodesy Symposia, vol 139. Springer, Berlin, Heidelberg. https://doi.org/10.1007/978-3-642-37222-3_69
Download citation
DOI: https://doi.org/10.1007/978-3-642-37222-3_69
Published:
Publisher Name: Springer, Berlin, Heidelberg
Print ISBN: 978-3-642-37221-6
Online ISBN: 978-3-642-37222-3
eBook Packages: Earth and Environmental ScienceEarth and Environmental Science (R0)