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| Titel |
Filtering of monthly GRACE gravity field solutions using time variable decorrelation by incorporating full covariance information |
| VerfasserIn |
Alexander Horvath, Michael Murböck, Roland Pail, Martin Horwath |
| Konferenz |
EGU General Assembly 2016
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 18 (2016) |
| Datensatznummer |
250132599
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| Publikation (Nr.) |
 EGU/EGU2016-13123.pdf |
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| Zusammenfassung |
| Aiming for an as accurate as possible estimation of mass trends in Antarctica or other
regions, based on global GRACE gravity field solutions, calls for best possible post
processing strategies. Decorrelation filters employing static covariance information have
already been developed in the past (e.g. DDK filter series by Jürgen Kusche 2007 & 2009),
but covariance information for a decade long recent time series was (except for the
ITG-GRACE2010 series) not publicly available since the publication of the ITSG temporal
gravity field model in October 2014. With this work we aim to use this time series with its
evolving correlation structures due to changing mission configuration (e.g. orbital height) and
instrument characteristics over time.
Proper reduction of correlated errors is a crucial step towards trend estimation. For this
purpose we analyzed the existing series of DDK filters based on static or simplified
assumptions on the correlation structure of spherical harmonic coefficients and
target signals. To analyze the potential gain using month to month full covariance
information we have tested the impact of certain simplifications (e.g. the ones applied for
the DDK filters) with respect to the full covariance information in a closed loop
simulator.
Based on the outcome of the simulated results we computed new time variable decorrelation
(VADER) filters using full error covariance information and investigated the impact on basin
scale mass change estimates in the Antarctic region. The work presented includes a
comprehensive assessment of the filter performance, accompanied by an intercomparison of
the mass change estimates based on the VADER filter solutions against the ones obtained
from DDK, Swenson & Wahr type and other filters as well as independently derived results
from e.g. radar altimetry. |
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