Validation of the EGSIEM GRACE gravity fields using GNSS coordinate timeseries and in-situ ocean bottom pressure records

verfasst von: Qiang Chen, Lea Poropat, Liangjing Zhang, Henryk Dobslaw, Matthias Weigelt, Tonie van Dam
Abstract: Over the 15 years of the Gravity Recovery and Climate Experiment (GRACE) mission, various data processing approaches were developed to derive time-series of global gravity fields based on sensor observations acquired from the two spacecrafts. In this paper, we compare GRACE-based mass anomalies provided by various processing groups against Global Navigation Satellite System (GNSS) station coordinate time-series and in-situ observations of ocean bottom pressure. In addition to the conventional GRACE-based global geopotential models from the main processing centers, we focus particularly on combined gravity field solutions generated within the Horizon2020 project European Gravity Service for Improved Emergency Management (EGSIEM). Although two validation techniques are fully independent from each other, it is demonstrated that they confirm each other to a large extent. Through the validation, we show that the EGSIEM combined long-term monthly solutions are comparable to CSR RL05 and ITSG2016, and better than the other three considered GRACE monthly solutions AIUB RL02, GFZ RL05a, and JPL RL05.1. Depending on the GNSS products, up to 25.6% mean Weighted Root-Mean-Square (WRMS) reduction is obtained when comparing GRACE to the ITRF2014 residuals over 236 GNSS stations. In addition, we also observe remarkable agreement at the annual period between GNSS and GRACE with up to 73% median WRMS reduction when comparing GRACE to the 312 EGSIEM-reprocessed GNSS time series. While the correspondence between GRACE and ocean bottom pressure data is overall much smaller due to lower signal to noise ratio over the oceans than over the continents, up to 50% agreement is found between them in some regions. The results fully confirm the conclusions found using GNSS.
Organisationseinheit(en): Institut für Erdmessung
Externe Organisation(en): University of Luxembourg
Helmholtz-Zentrum Potsdam Deutsches GeoForschungsZentrum
Typ: Artikel
Journal: Remote sensing
Band: 10
Anzahl der Seiten: 20
ISSN: 2072-4292
Publikationsdatum: 07.12.2018
Publikationsstatus: Veröffentlicht
Peer-reviewed: Ja
ASJC Scopus Sachgebiete: Erdkunde und Planetologie (insg.)
Elektronische Version(en): https://doi.org/10.3390/rs10121976 (Zugang: Offen)
: Details im Forschungsportal „Research@Leibniz University“

BibTeX

@article{5ecf8cbd0ba547de822ab275055aa39e,
title = "Validation of the EGSIEM GRACE gravity fields using GNSS coordinate timeseries and in-situ ocean bottom pressure records",
abstract = "Over the 15 years of the Gravity Recovery and Climate Experiment (GRACE) mission, various data processing approaches were developed to derive time-series of global gravity fields based on sensor observations acquired from the two spacecrafts. In this paper, we compare GRACE-based mass anomalies provided by various processing groups against Global Navigation Satellite System (GNSS) station coordinate time-series and in-situ observations of ocean bottom pressure. In addition to the conventional GRACE-based global geopotential models from the main processing centers, we focus particularly on combined gravity field solutions generated within the Horizon2020 project European Gravity Service for Improved Emergency Management (EGSIEM). Although two validation techniques are fully independent from each other, it is demonstrated that they confirm each other to a large extent. Through the validation, we show that the EGSIEM combined long-term monthly solutions are comparable to CSR RL05 and ITSG2016, and better than the other three considered GRACE monthly solutions AIUB RL02, GFZ RL05a, and JPL RL05.1. Depending on the GNSS products, up to 25.6% mean Weighted Root-Mean-Square (WRMS) reduction is obtained when comparing GRACE to the ITRF2014 residuals over 236 GNSS stations. In addition, we also observe remarkable agreement at the annual period between GNSS and GRACE with up to 73% median WRMS reduction when comparing GRACE to the 312 EGSIEM-reprocessed GNSS time series. While the correspondence between GRACE and ocean bottom pressure data is overall much smaller due to lower signal to noise ratio over the oceans than over the continents, up to 50% agreement is found between them in some regions. The results fully confirm the conclusions found using GNSS.",
keywords = "Combined solutions, EGSIEM, GNSS time series, GRACE, In-situ OBP records, Validation",
author = "Qiang Chen and Lea Poropat and Liangjing Zhang and Henryk Dobslaw and Matthias Weigelt and {van Dam}, Tonie",
note = "Funding Information: This research was supported by the European Union{\textquoteright}s Horizon2020 research and innovation program under the Grant Agreement No.637010. Acknowledgments: We are grateful to Paul Rebischung from IGN (France) and JPL (USA) for providing us the GNSS products. We thank Andreas Macrander from MFRI (Marine and Freshwater Research Institute, Reykjavik, Iceland) for compiling and sharing his OBP database. MPIOM model data is accessible from isdc.gfz-potsdam.de/esmdata. MPIOM simulations were performed at Deutsches Klimarechenzentrum in Hamburg, Germany. ",
year = "2018",
month = dec,
day = "7",
doi = "10.3390/rs10121976",
language = "English",
volume = "10",
journal = "Remote sensing",
issn = "2072-4292",
publisher = "Multidisciplinary Digital Publishing Institute",
number = "12",
}