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A Statistical Filtering Approach for Gravity Recovery and Climate Experiment (GRACE) Gravity DataWe describe and analyze a statistical filtering approach for GRACE data that uses a parametrized model for the temporal evolution of the GRACE coefficients. After least-squares adjustment, a statistical test is performed to assess the significance of the estimated parameters. If the test is passed, the parameters are used by the filter in the reconstruction of the field; otherwise they are rejected. The test is performed, and the filter is formed, separately for annual components of the model and the trend. This new approach is distinct from Gaussian smoothing since it uses the data themselves to test for specific components of the time-varying gravity field. The statistical filter appears inherently to remove most of the "stripes" present in the GRACE fields, although destriping the fields prior to filtering seems to help the trend recovery. We demonstrate that the statistical filter produces reasonable maps for the annual components and trend. We furthermore assess the statistical filter for the annual components using ground-based GPS data in South America by assuming that the annual component of the gravity signal is associated only with groundwater storage. The un-destriped, statistically filtered field has a X2 value relative to the GPS data consistent with the best result from smoothing. In the space domain, the statistical filters are qualitatively similar to Gaussian smoothing. Unlike Gaussian smoothing, however, the statistical filter has significant sidelobes, including large negative sidelobes on the north-south axis, potentially revealing information on the errors, and the correlations among the errors, for the GRACE coefficients.
Document ID
20080034474
Acquisition Source
Goddard Space Flight Center
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Davis. J. L.
(Harvard-Smithsonian Center for Astrophysics Cambridge, MA, United States)
Tamisiea, M. E.
(Harvard-Smithsonian Center for Astrophysics Cambridge, MA, United States)
Elosegui, P.
(Consejo Superior de Investigaciones Cientificas Barcelona, Spain)
Mitrovica, J. X.
(Toronto Univ. Ontario, Canada)
Hill, E. M.
(Harvard-Smithsonian Center for Astrophysics Cambridge, MA, United States)
Date Acquired
August 24, 2013
Publication Date
April 18, 2008
Publication Information
Publication: Journal of Geophysical Research
Publisher: American Geophysical Union
Volume: 113
Subject Category
Meteorology And Climatology
Funding Number(s)
CONTRACT_GRANT: NNG04GF09G
Distribution Limits
Public
Copyright
Other

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