Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Regional Geoid Determination Methods for the Era of Satellite Gravimetry: Numerical Investigations Using Synthetic Earth Gravity Models
KTH, Superseded Departments, Infrastructure.
2004 (English)Doctoral thesis, monograph (Other scientific)
Abstract [en]

It is the purpose of this thesis to investigate different regional geoid determination methods with respect to their feasibility for use with a future GOCE satellite-only Earth Gravity Model (EGM). This includes investigations of various techniques, which involve different approximations, as well as the expected accuracy. Many, but not all, of these tasks are tested by means of Synthetic Earth Gravity Models (SEGMs). The study is limited to remove-compute-restore methods using Helmert condensation and to Sjöberg's combined approach (method with additive corrections).

First, a number of modifications of Stokes' formula are tested with respect to their compatibility with a GOCE EGM having negligible commission error. It is concluded that the least squares modification method should be preferred.

Next, two new point-mass SEGMs are constructed in such a way that the resulting models have degree variances representative for the full and topographically reduced gravity fields, respectively. These SEGMs are then used to test different methods for modified Stokes' integration and downward continuation. It is concluded that the combined method requires dense observations, obtained from the given surface anomalies by interpolation using a reduction for all known density anomalies, most notably the topography. Examples of other conclusions are that the downward continuation method of Sjöberg (2003a) performs well numerically.

To be able to test topographic corrections, another SEGM is constructed starting from the reduced point-mass model, to which the topography, bathymetry and isostatic compensation are added. This model, which is called the Nordic SEGM, is then applied to test one strict and one more approximate approach to Helmert's condensation. One conclusion here is that Helmert's 1st method with the condensation layer 21 km below sea level should be preferred to Helmert's 2nd condensation strategy.

The thesis ends with a number of investigations of Sjöberg's combined approach to geoid determination, which include tests using the Nordic SEGM. It is concluded that the method works well in practice for a region like Scandinavia. It is finally shown how the combined strategy may preferably be used to estimate height anomalies directly.

Place, publisher, year, edition, pages
Stockholm: Infrastruktur , 2004. , xv, 246 p.
Series
TRITA-INFRA, ISSN 1651-0216 ; 04:033
Keyword [en]
Earth sciences, geoid determination, GOCE, synthetic earth gravity models, kernel modification, downward continuation
Keyword [sv]
Geovetenskap
National Category
Earth and Related Environmental Sciences
Identifiers
URN: urn:nbn:se:kth:diva-55ISBN: 91-7323-097-9 (print)OAI: oai:DiVA.org:kth-55DiVA: diva2:14396
Public defence
2004-11-26, E3, KTH, Lindstedsvägen 3, Stockholm, 13:00
Opponent
Supervisors
Available from: 2004-11-26 Created: 2004-11-26 Last updated: 2016-11-24

Open Access in DiVA

fulltext(8257 kB)5012 downloads
File information
File name FULLTEXT01.pdfFile size 8257 kBChecksum MD5
0d03ae8dec5180da25c28170e67450b3ea77f58435d5962e338961ad68a6b0454f75cb74
Type fulltextMimetype application/pdf

Search in DiVA

By author/editor
Ågren, Jonas
By organisation
Infrastructure
Earth and Related Environmental Sciences

Search outside of DiVA

GoogleGoogle Scholar
Total: 5012 downloads
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

isbn
urn-nbn

Altmetric score

isbn
urn-nbn
Total: 1430 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf