The reduction of aliasing in gravity anomalies and geoid heights using digital terrain data
Observations of gravity can be aliased by virtue of the logistics involved in collecting these data in the field. For instance, gravity measurements are often made in more accessible lowland areas where there are roads and tracks, thus omitting areas of higher relief in between. The gravimetric dete...
| Main Authors: | , |
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| Format: | Journal Article |
| Published: |
Blackwell Publishing Ltd
2000
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| Online Access: | http://hdl.handle.net/20.500.11937/12714 |
| _version_ | 1848748154056343552 |
|---|---|
| author | Featherstone, Will Kirby, Jonathan |
| author_facet | Featherstone, Will Kirby, Jonathan |
| author_sort | Featherstone, Will |
| building | Curtin Institutional Repository |
| collection | Online Access |
| description | Observations of gravity can be aliased by virtue of the logistics involved in collecting these data in the field. For instance, gravity measurements are often made in more accessible lowland areas where there are roads and tracks, thus omitting areas of higher relief in between. The gravimetric determination of the geoid requires mean terrain-corrected free-air anomalies; however, anomalies based only on the observations in lowland regions are not necessarily representative of the true mean value over the topography. A five-stage approach is taken that uses a digital elevation model, which provides a more accurate representation of the topography than the gravity observation elevations, to reduce the unrepresentative sampling in the gravity observations. When using this approach with the Australian digital elevation model, the terrain-corrected free-air anomalies generated from the Australian gravity data base change by between 77.075 and -84.335 mgal (-0.193 mgal mean and 2.687 mgal standard deviation). Subsequent gravimetric geoid computations are used to illustrate the effect of aliasing in the Australian gravity data upon the geoid. The difference between 'aliased' and 'non-aliased' gravimetric geoid solutions varies by between 0.732 and -1.816 m (-0.058 m mean and 0.122 m standard deviation). Based on these conceptual arguments and numerical results, it is recommended that supplementary digital elevation information be included during the estimation of mean gravity anomalies prior to the computation of a gravimetric geoid model. |
| first_indexed | 2025-11-14T07:00:31Z |
| format | Journal Article |
| id | curtin-20.500.11937-12714 |
| institution | Curtin University Malaysia |
| institution_category | Local University |
| last_indexed | 2025-11-14T07:00:31Z |
| publishDate | 2000 |
| publisher | Blackwell Publishing Ltd |
| recordtype | eprints |
| repository_type | Digital Repository |
| spelling | curtin-20.500.11937-127142017-09-13T16:02:38Z The reduction of aliasing in gravity anomalies and geoid heights using digital terrain data Featherstone, Will Kirby, Jonathan Australia digital terrain models geoid Aliasing gravity Observations of gravity can be aliased by virtue of the logistics involved in collecting these data in the field. For instance, gravity measurements are often made in more accessible lowland areas where there are roads and tracks, thus omitting areas of higher relief in between. The gravimetric determination of the geoid requires mean terrain-corrected free-air anomalies; however, anomalies based only on the observations in lowland regions are not necessarily representative of the true mean value over the topography. A five-stage approach is taken that uses a digital elevation model, which provides a more accurate representation of the topography than the gravity observation elevations, to reduce the unrepresentative sampling in the gravity observations. When using this approach with the Australian digital elevation model, the terrain-corrected free-air anomalies generated from the Australian gravity data base change by between 77.075 and -84.335 mgal (-0.193 mgal mean and 2.687 mgal standard deviation). Subsequent gravimetric geoid computations are used to illustrate the effect of aliasing in the Australian gravity data upon the geoid. The difference between 'aliased' and 'non-aliased' gravimetric geoid solutions varies by between 0.732 and -1.816 m (-0.058 m mean and 0.122 m standard deviation). Based on these conceptual arguments and numerical results, it is recommended that supplementary digital elevation information be included during the estimation of mean gravity anomalies prior to the computation of a gravimetric geoid model. 2000 Journal Article http://hdl.handle.net/20.500.11937/12714 10.1046/j.1365-246X.2000.00082.x Blackwell Publishing Ltd unknown |
| spellingShingle | Australia digital terrain models geoid Aliasing gravity Featherstone, Will Kirby, Jonathan The reduction of aliasing in gravity anomalies and geoid heights using digital terrain data |
| title | The reduction of aliasing in gravity anomalies and geoid heights using digital terrain data |
| title_full | The reduction of aliasing in gravity anomalies and geoid heights using digital terrain data |
| title_fullStr | The reduction of aliasing in gravity anomalies and geoid heights using digital terrain data |
| title_full_unstemmed | The reduction of aliasing in gravity anomalies and geoid heights using digital terrain data |
| title_short | The reduction of aliasing in gravity anomalies and geoid heights using digital terrain data |
| title_sort | reduction of aliasing in gravity anomalies and geoid heights using digital terrain data |
| topic | Australia digital terrain models geoid Aliasing gravity |
| url | http://hdl.handle.net/20.500.11937/12714 |