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| Titel |
The comparison of downward continued global models and true geoid ondulations |
| VerfasserIn |
Daniele Sampietro, Giovanna Sona |
| Konferenz |
EGU General Assembly 2010
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 12 (2010) |
| Datensatznummer |
250041976
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| Zusammenfassung |
| The recent release by the US National Geospatial Intellence Agency of the Earth
Gravitational Model EGM08 provides a description of the Earth gravity field with
unprecedented resolution and accuracy.
Since EGM08 actually yields height anomalies ζ, a corrective term depending on the
topography, i.e. the downward continuation of ζsgs needed to estimate the ondulations of the
geoid N.
In this work, a simple correction model to convert ζ into N is derived and implemented.
Results obtained with this new approach have been compared with the corrective term
computed by EGM08, based on a description of the Earth surface in terms of spherical
harmonic expansion, and with the other well known (classical) topographic correction that
makes use of Bouguer anomalies and orthometric heights.
Numerical comparisons among the three different approximations have been performed
over a wide area in Europe.
The results of the three methods have been checked over Italy using GPS/leveling data.
Results show a general good agreement among the three corrections, with differences of
centimeter order (r.m.s) and higher differences (up to 30 centimeters) occurring in high
mountainous areas (Alps).
The present research has been partially funded by ASI through the GOCE ITALY project. |
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