Abstract
The launch of dedicated satellite missions at the beginning of the 2000s led to significant improvement in the determination of Earth gravity field models. As a consequence of this progress, both the accuracies and the spatial resolutions of the global geopotential models increased. However, the spectral behaviors and the accuracies of the released models vary mainly depending on their computation strategies. These strategies are briefly explained in this article. Comprehensive quality assessment of the gravity field models by means of spectral and statistical analyses provides a comparison of the gravity field mapping accuracies of these models, as well as providing an understanding of their progress. The practical benefit of these assessments by means of choosing an optimal model with the highest accuracy and best resolution for a specific application is obvious for a broad range of geoscience applications, including geodesy and geophysics, that employ Earth gravity field parameters in their studies. From this perspective, this study aims to evaluate the GOCE High-Level Processing Facility geopotential models including recently published sixth releases using different validation methods recommended in the literature, and investigate their performances comparatively and in addition to some other models, such as GOCO05S, GOGRA04S and EGM2008. In addition to the validation statistics from various countries, the study specifically emphasizes the numerical test results in Turkey. It is concluded that the performance improves from the first generation RL01 models toward the final RL05 models, which were based on the entire mission data. This outcome was confirmed when the releases of different computation approaches were considered. The accuracies of the RL05 models were found to be similar to GOCO05S, GOGRA04S and even to RL06 versions but better than EGM2008, in their maximum expansion degrees. Regarding the results obtained from these tests using the GPS/leveling observations in Turkey, the contribution of the GOCE data to the models was significant, especially between the expansion degrees of 100 and 250. In the study, the tested geopotential models were also considered for detailed geoid modeling using the remove-compute-restore method. It was found that the best-fitting geopotential model with its optimal expansion degree (please see the definition of optimal degree in the article) improved the high-frequency regional geoid model accuracy by almost 15%.
Original language | English |
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Article number | 586 |
Journal | Remote Sensing |
Volume | 12 |
Issue number | 3 |
DOIs | |
Publication status | Published - 1 Feb 2020 |
Bibliographical note
Publisher Copyright:© 2020 by the authors.
Funding
This research was funded by The Scientific and Technological Research Council of Turkey (TÜBI˙TAK), grant number 114Y581 and Istanbul Technical University Scientific Research Projects (ITU BAP) funds, grant number 38828. We acknowledge International Center for Global Earth Models (ICGEM) at GFZ German Research Center for Geosciences that the used geopotential models were obtained from the service's data center.
Funders | Funder number |
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Istanbul Technical University Scientific Research Projects | |
Türkiye Bilimsel ve Teknolojik Araştirma Kurumu | 114Y581 |
Bilimsel Araştırma Projeleri Birimi, İstanbul Teknik Üniversitesi | 38828 |
Keywords
- Geoid
- GOCE
- GOCE High-Level Processing Facility (HPF), earth gravity field
- GRACE
- Gravity field satellite missions
- Spectral enhancement method (SEM), GPS/leveling