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| Titel |
Low degree Earth’s gravity coefficients determined from different space geodetic observations and climate models |
| VerfasserIn |
Małgorzata Wińska, Jolanta Nastula |
| Konferenz |
EGU General Assembly 2017
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 19 (2017) |
| Datensatznummer |
250138362
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| Publikation (Nr.) |
 EGU/EGU2017-1346.pdf |
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| Zusammenfassung |
| Large scale mass redistribution and its transport within the Earth system causes
changes in the Earth’s rotation in space, gravity field and Earth’s ellipsoid shape.
These changes are observed in the ΔC21, ΔS21, and ΔC20 spherical harmonics
gravity coefficients, which are proportional to the mass load-induced Earth rotational
excitations.
In this study, linear trend, decadal, inter-annual, and seasonal variations of low degree
spherical harmonics coefficients of Earth’s gravity field, determined from different
space geodetic techniques, Gravity Recovery and Climate Experiment (GRACE),
satellite laser ranging (SLR), Global Navigation Satellite System (GNSS), Earth
rotation, and climate models, are examined. In this way, the contribution of each
measurement technique to interpreting the low degree surface mass density of the Earth is
shown.
Especially, we evaluate an usefulness of several climate models from the Coupled Model
Intercomparison Project phase 5 (CMIP5) to determine the low degree Earth’s gravity
coefficients using GRACE satellite observations. To do that, Terrestrial Water Storage (TWS)
changes from several CMIP5 climate models are determined and then these simulated data
are compared with the GRACE observations.
Spherical harmonics ΔC21, ΔS21, and ΔC20 changes are calculated as the sum of
atmosphere and ocean mass effect (GAC values) taken from GRACE and a land surface
hydrological estimate from the selected CMIP5 climate models.
Low degree Stokes coefficients of the surface mass density determined from GRACE,
SLR, GNSS, Earth rotation measurements and climate models are compared to each other in
order to assess their consistency. The comparison is done by using different types of
statistical and signal processing methods. |
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