Details
| Original language | English |
|---|---|
| Article number | 1976 |
| Number of pages | 20 |
| Journal | Remote sensing |
| Volume | 10 |
| Issue number | 12 |
| Publication status | Published - 7 Dec 2018 |
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
ASJC Scopus subject areas
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In: Remote sensing, Vol. 10, No. 12, 1976, 07.12.2018.
Research output: Contribution to journal › Article › Research › peer review
}
TY - JOUR
T1 - Validation of the EGSIEM GRACE gravity fields using GNSS coordinate timeseries and in-situ ocean bottom pressure records
AU - Chen, Qiang
AU - Poropat, Lea
AU - Zhang, Liangjing
AU - Dobslaw, Henryk
AU - Weigelt, Matthias
AU - van Dam, Tonie
N1 - Funding Information: This research was supported by the European Union’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.
PY - 2018/12/7
Y1 - 2018/12/7
N2 - 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.
AB - 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.
KW - Combined solutions
KW - EGSIEM
KW - GNSS time series
KW - GRACE
KW - In-situ OBP records
KW - Validation
UR - http://www.scopus.com/inward/record.url?scp=85058898395&partnerID=8YFLogxK
U2 - 10.3390/rs10121976
DO - 10.3390/rs10121976
M3 - Article
AN - SCOPUS:85058898395
VL - 10
JO - Remote sensing
JF - Remote sensing
SN - 2072-4292
IS - 12
M1 - 1976
ER -