Estimating Sub-Monthly Global Mass Transport Signals Using GRACE, GPS and OBP Data Sets
In an effort to learn more about the sub-monthly variations in the global mass transport processes of the Earth, a study has been performed in which the feasibility of using weekly GRACE gravity solutions, in combination with GPS displacement data and ocean bottom pressure (OBP) models, is examined. A sensitivity study was conducted in which a range of solutions using different combinations of these three data sets were compared to each other, and with the time span of each combination ranging from 1 to 4 weeks. Data sets included weekly GFZ RL04 GRACE covariance matrices, as well as IGS GPS solutions and a new FESOM global OBP model, developed at AWI. The results showed that the temporal resolution of the solutions could be increased, while still maintaining reasonable levels of accuracy, if either GPS or OBP data were included in the combination. In particular, a 2-week triple combination of GRACE, GPS and OBP data was found to have approximately the same accuracy over land as a standard monthly GRACE solution, up to degree and order 30. These results provide encouraging support for future work involving real-data combinations.
KeywordsInternational GNSS Service Triple Combination Spherical Harmonic Coefficient Tropospheric Zenith Delay Ocean Bottom Pressure
Support for this study was provided in part by the Nederlandse Organisatie voor Wetenschappelijk Onderzoek (NWO), Aard- en Levenswetenschappen (ALW) division, grant number ALW1PJ/07011, and the German Research Foundation (DFG), under grant KU 1207/6-1, within the Special Priority Program SPP 1257 Mass Transport and Mass Distribution in the System Earth.
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