Abstract
<p>We analyze more than 10 years of Global Positioning System (GPS) height residuals and vertical displacements predicted from surface mass loading observed by the Gravity Recovery and Climate Experiment (GRACE) for 36 International GNSS Service (IGS) stations over Europe. Seasonal surface displacements, mostly due to atmospheric and hydrological loading, are significant in both GPS and GRACE measurements. With an extended time period, our new analysis based on release 05 GRACE data from Center for Space Research (CSR) shows considerably improved agreement between GPS and GRACE than that from previous studies, for not only annual but also interannual signals. The GPS height residual series at most stations exhibit reduced weighted root-mean-squares (WRMS) after removing GRACE-derived vertical displacements, which is attributed to improved accuracy of both GPS and GRACE data products. Furthermore, we demonstrate the necessity of reducing leakage bias in GRACE estimates for the study of surface loading deformation using GRACE satellite gravity observations.</p>
Highlights
Mass transport and redistribution within the Earth system, including the atmosphere, hydrosphere, ocean, cryosphere, mantle and core, are driving forces of temporal variations of geodetic observables, such as gravity change, Earth’s rotation, geocenter motion and elastic surface displacements [Mangiarotti et al 2001]
We focus on the seasonal and interannual variations in vertical displacements using updated Global Positioning System (GPS) data, and compare them with the new version of Gravity Recovery and Climate Experiment (GRACE) data, with the consideration of degree-1 geocenter terms provided by Swenson et al [2008]
Assuming that the GRACE data are subject to an equivalent attenuation effect, we can apply the Global Land Data Assimilation System (GLDAS) model derived scaling factors to vertical displacements predicted by GRACE GSM products (Figure 8c) to obtain the “restored” GRACE results (Figure 8d)
Summary
Mass transport and redistribution within the Earth system, including the atmosphere, hydrosphere, ocean, cryosphere, mantle and core, are driving forces of temporal variations of geodetic observables, such as gravity change, Earth’s rotation, geocenter motion and elastic surface displacements [Mangiarotti et al 2001] These geodetic observables can be measured by modern space geodetic techniques with increasing and unprecedented accuracy. van Dam et al [2007] showed that the annual amplitudes of vertical deformation signals varied considerably in GPS heights from site to site over western Europe, and deviated from GRACE-derived vertical displacements They suggested that the discrepancy was mainly due to technique errors in GPS data processing. Comparison purposes, we select the 36 sites in western Europe that have been included in previous studies [e.g., van Dam et al 2007]
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
