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Mass change from GRACE: a simulated comparison of Level-1B analysis techniques

Citation

Andrews, SB and Moore, P and King, MA, Mass change from GRACE: a simulated comparison of Level-1B analysis techniques, Geophysical Journal International, 200, (1) pp. 503-518. ISSN 0956-540X (2015) [Refereed Article]


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Copyright Statement

The Authors 2014. Published by Oxford University Press on behalf of The Royal Astronomical Society. Licenced under Creative Commons Attribution 3.0 Unported (CC BY 3.0) http://creativecommons.org/licenses/by/3.0/

DOI: doi:10.1093/gji/ggu402

Abstract

Spherical harmonic and mascon parameters have both been successfully applied in the recovery of time-varying gravity fields from Gravity Recovery and Climate Experiment (GRACE). However, direct comparison of any mass flux is difficult with solutions generated by different groups using different codes and algorithms. It is therefore opportune to compare these methodologies, within a common software base, to understand potential limitations associated with each technique. Here we use simulations to recover a known monthly surface mass distribution from GRACE KBRR data. The ability of spherical harmonic and mascon parameters to resolve basin-level mass change is quantified with an assessment of how the noise and errors, inherent in GRACE solutions, are handled. Recovery of a noise and error free GLDAS anomaly revealed no quantifiable difference between spherical harmonic and mascon parameters. Expansion of the GLDAS anomaly to degree and order 120 shows that both spherical harmonic and mascon parameters are affected by comparable omission errors. However, the inclusion of realistic KBRR noise and errors in the simulations reveals the advantage of the mascon parameters over spherical harmonics at reducing noise and errors in the higher degree and order harmonics with an rms (cm of EWH) to the GLDAS anomaly of 10.0 for the spherical harmonic solution and 8.8 (8.6) for the 4(2) mascon solutions. The introduction of a constraint matrix in the mascon solution based on parameters that share geophysical similarities is shown to further reduce the signal lost at all degrees. The recovery of a simulated Antarctic mass loss signal shows that the mascon methodology is superior to spherical harmonics for this region with an rms (cm of EWH) of 8.7 for the 2 mascon solution compared to 10.0 for the spherical harmonic solution. Investigating the noise and errors for a month when the satellites were in resonance revealed both the spherical harmonic and mascon methodologies are able to recover the GLDAS and Antarctic mass loss signal with either a comparable (spherical harmonic) or improved (mascon) rms compared to non-resonance periods.

Item Details

Item Type:Refereed Article
Keywords:GRACE, hydrology, Antarctica, time-variable gravity, simulation, inverse theory, satellite geodesy, gravity anomalies and Earth structure, global change from geodesy
Research Division:Engineering
Research Group:Geomatic Engineering
Research Field:Geodesy
Objective Division:Expanding Knowledge
Objective Group:Expanding Knowledge
Objective Field:Expanding Knowledge in the Earth Sciences
Author:King, MA (Professor Matt King)
ID Code:102145
Year Published:2015
Funding Support:Australian Research Council (FT110100207)
Web of Science® Times Cited:5
Deposited By:Geography and Environmental Studies
Deposited On:2015-07-30
Last Modified:2017-10-24
Downloads:118 View Download Statistics

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