HAL : hal-00533212, version 1

DOI : 10.1016/j.rse.2010.08.017

Code IRD Horizon : fdi:010053355

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Remote Sensing of Environment 115, 1 (2011) 187-204

An independent component analysis filtering approach for estimating continental hydrology in the GRACE gravity data

Frédéric Frappart 1, Guillaume Ramillien 2, Marc Leblanc 3, Sarah Tweed 4, Marie-Paule Bonnet 1, Philippe Maisongrande 5

CYMENT; Australian Research Council grant DP0666300 Collaboration(s)

(01/2011)

An approach based on Independent Component Analysis (ICA) has been applied on a combination of monthly GRACE satellite solutions computed from official providers (CSR, JPL and GFZ), to separate useful geophysical signals from important striping undulations. We pre-filtered the raw GRACE Level-2 solutions using Gaussian filters of 300, 400, 500-km of radius to verify the non-Gaussianity condition which is necessary to apply the ICA. This linear inverse approach ensures to separate components of the observed gravity field which are statistically independent. The most energetic component found by ICA corresponds mainly to the contribution of continental water mass change. Series of ICA-estimated global maps of continental water storage have been produced over 08/2002–07/2009. Our ICA estimates were compared with the solutions obtained using other post-processing of GRACE Level-2 data, such as destriping and Gaussian filtering, at global and basin scales. Besides, they have been validated with in situ measurements in the Murray–Darling Basin. Our computed ICA grids are consistent with the different approaches. Moreover, the ICA-derived time series of water masses showed less north–south spurious gravity signals and improved filtering of unrealistic hydrological features at the basin-scale compared with solutions obtained using other filtering methods.

1 :	Laboratoire des Mécanismes et Transfert en Géologie (LMTG)
	CNRS : UMR5563 – Observatoire Midi-Pyrénées – Université Paul Sabatier [UPS] - Toulouse III – Institut de recherche pour le développement [IRD] : UMR154
2 :	Dynamique terrestre et planétaire (DTP)
	CNRS : UMR5562 – Observatoire Midi-Pyrénées – INSU – Université Paul Sabatier [UPS] - Toulouse III
3 :	Hydrological Sciences Research Unit
	School of Earth and Environmental Sciences
4 :	Hydrological Sciences Research Unit
	School of Earth and Environmental Sciences
5 :	Laboratoire d'études en Géophysique et océanographie spatiales (LEGOS)
	CNRS : UMR5566 – Institut de recherche pour le développement [IRD] – CNES – Observatoire Midi-Pyrénées – INSU – Université Paul Sabatier [UPS] - Toulouse III

Domaine

:

Planète et Univers/Sciences de la Terre

Mots Clés : Filtering technique – Gravimetry from space – Hydrology – Independent component analysis

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Contributeur : Frédéric Frappart <>

Soumis le : Vendredi 5 Novembre 2010, 14:48:51

Dernière modification le : Vendredi 5 Novembre 2010, 21:35:30