SLR, GRACE and Swarm Gravity Field Determination and Combination

Meyer, Ulrich; Sosnica, K.; Arnold, Daniel; Dahle, C.; Thaller, D.; Dach, Rolf; Jäggi, Adrian (2019). SLR, GRACE and Swarm Gravity Field Determination and Combination. Remote sensing, 11(8), p. 956. Molecular Diversity Preservation International MDPI 10.3390/rs11080956

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Satellite gravimetry allows for determining large scale mass transport in the system Earth and to quantify ice mass change in polar regions. We provide, evaluate and compare a long time-series of monthly gravity field solutions derived either by satellite laser ranging (SLR) to geodetic satellites, by GPS and K-band observations of the GRACE mission, or by GPS observations of the three Swarm satellites. While GRACE provides gravity signal at the highest spatial resolution, SLR sheds light on mass transport in polar regions at larger scales also in the pre- and post-GRACE era. To bridge the gap between GRACE and GRACE Follow-On, we also derive monthly gravity fields using Swarm data and perform a combination with SLR. To correctly take all correlations into account, this combination is performed on the normal equation level. Validating the Swarm/SLR combination against GRACE during the overlapping period January 2015 to June 2016, the best fit is achieved when down-weighting Swarm compared to the weights determined by variance component estimation. While between 2014 and 2017 SLR alone slightly overestimates mass loss in Greenland compared to GRACE, the combined gravity fields match significantly better in the overlapping time period and the RMS of the differences is reduced by almost 100 Gt. After 2017 both, SLR and Swarm indicate moderate mass gain in Greenland.

Item Type:

Journal Article (Original Article)

Division/Institute:

08 Faculty of Science > Institute of Astronomy

UniBE Contributor:

Meyer, Ulrich; Arnold, Daniel; Dach, Rolf and Jäggi, Adrian

Subjects:

500 Science > 520 Astronomy

ISSN:

2072-4292

Publisher:

Molecular Diversity Preservation International MDPI

Language:

English

Submitter:

Pierre Fridez

Date Deposited:

31 Jul 2019 16:35

Last Modified:

31 Jul 2019 16:43

Publisher DOI:

10.3390/rs11080956

BORIS DOI:

10.7892/boris.132230

URI:

https://boris.unibe.ch/id/eprint/132230

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