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Observed changes in the Earth's dynamic oblateness from GRACE data and geophysical models.
1Department of Geoscience and Remote Sensing, Delft University of Technology, Delft, The Netherlands.
Journal of Geodesy
|February 23, 2016
Summary
This study introduces a new method to track Earth
Area of Science:
- Geophysics and Earth System Science
- Geodesy and Satellite Gravimetry
Background:
- Estimating monthly changes in Earth's dynamic oblateness is crucial for understanding global geophysical processes.
- Existing methods may face challenges with data integration and signal processing, particularly in coastal regions.
Purpose of the Study:
- To develop and validate a novel methodology for monthly estimation of Earth's dynamic oblateness.
- To assess the agreement between the new method and existing satellite laser ranging (SLR) data.
Main Methods:
- Utilized monthly Gravity Recovery and Climate Experiment (GRACE) gravity solutions.
- Integrated an ocean bottom pressure model and a glacial isostatic adjustment (GIA) model.
- Implemented signal leakage reduction in coastal areas and accounted for self-attraction and loading effects.
Main Results:
- The proposed time series showed remarkable agreement with SLR-based solutions.
- Seasonal variations were found to be insensitive to the choice of GRACE solutions.
- Careful data processing (reducing signal leakage and accounting for oceanic loading) is key for accurate de-trended solutions.
Conclusions:
- The new methodology provides a reliable approach for monthly oblateness change estimation.
- The accuracy of trend estimates is currently limited by uncertainties in GIA models.
- Further refinement of GIA models is necessary for improving long-term trend accuracy.
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