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| Titel |
A validation toolbox for time variable gravity fields from GRACE |
| VerfasserIn |
Ilias Daras, Christian Gruber, Martin Schmeer, Christoph Dahle, Frank Flechtner |
| Konferenz |
EGU General Assembly 2011
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 13 (2011) |
| Datensatznummer |
250055824
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| Zusammenfassung |
| Numerous global gravity field series have been published by different processing centers
since the launch of GRACE mission in March 2002. These series provide a direct
measurement of mass exchange and are widely used by geoscientists to investigate
time-varying mass variation phenomena for applications in Earth system sciences. The
German Research Center for Geosciences (GFZ) as part of the GRACE Science Data System
(SDS) is routinely processing its current EIGEN-GRACE05S (or RL04 in the SDS
nomenclature) time series since end of 2006. Using updated background models and modified
processing standards, a consistently reprocessed time series of the complete GRACE mission
called EIGEN-GRACE06S (RL05) will be provided by GFZ within the next few months. An
integrated validation toolbox for computing the external accuracy of those series and compare
them with RL04 as well as series from other centers is currently being developed in
GFZ.
The structure of the validation toolbox is multifold. GRACE is capable of observing
oceaning mass redistribution. Hence GRACE gravity time series are compared with in-situ
ocean bottom pressure (OBP) recorder series located worldwide and their correlation is
computed. On the other hand, by apropriate treatment of the data, surface displacements
derived by GRACE are also compared with GPS coordinate time series, as well as GNSS
leveling. Another statistical subtool uses regional masks and retrieves extreme, mean and
wRMS values of gravity functional for “quite” regions where low or minimal variability is
expected. The near-zero expected mean value of those regions (ex. Sahara desert) serves as
a criterion for the quality of the gravity field. The same statistical inspection is
also performed in basin regions (ex. Amazon), exploiting hydrological models and
annual/semiannual signals. Another indication is the correlation of GRACE fields to
flow accumulation by analyzing DEMs representing sloping terrain in selected
basins.
This poster will focus on the results of the validation toolbox for EIGEN-GRACE05S
(RL04) series as well as results for EIGEN-GRACE06S (RL05). |
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