Measuring and Modeling Solid Earth – Cryosphere Gravimetric Signals in GRACE and Future Satellite Missions

Abstract:

Based on over a decade (2002-present) of Gravity Recovery and Climate Experiment (GRACE) gravity measurements, the results from southern Alaska indicate region-specific trends of annual ice mass loss and large variable seasonal mass fluctuations. Numerical modeling of the solid Earth response to cryosphere change on a variety of temporal and spatial scales plays a critical role in supporting the interpretation of time-variable gravity and other geodetic data in southern Alaska. Additionally, in this tectonically active region, the GRACE data are predicted to include ongoing mass change associated with seismic cycle processes including the viscoelastic response to the M 9.2 1964 Prince William Sound earthquake that influences our estimates of ice mass loss trends. Here, we highlight our results of numerical modeling of region specific contributing geophysical signals within the GRACE data. Our numerical modeling of the solid Earth response to cryosphere changes and earthquakes includes extrapolations of rock-mechanics based constitutive theories to the mantle and crustal rheology used in our regional finite element and global normal-mode modeling. With the longer time series provided by GRACE-GRACE-FO, and possibly enhanced spatial resolution of GRACE-FO and other future mission gravimetric data, we anticipate better characterization of the temporal and spatial nature of cryosphere-solid Earth interaction signals. These constraints will inform optimal strategies for exploiting gravimetric data from other tectonically active regions with cryosphere changes including Patagonia and Iceland.