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Improved models of West Antarctic glacial isostatic adjustment through new crustal motion data
A research project of the Department of Geography.
This project addresses the current uncertainty in the present-day contribution of the West Antarctic Ice Sheet to global sea level rise. These estimates are primarily derived from space geodetic (altimetry or time-variable gravity) measurements, with time-variable gravity data from the GRACE satellite mission the only technique capable of determining ice mass balance for the entire ice sheet. Estimates of ice mass change from the total mass change (observed by GRACE) are, however, severely limited due to the large differences between contemporary models of Antarctic glacial isostatic adjustment (GIA). Indeed, recent published estimates of ice mass change for West Antarctica are swamped by the present uncertainty in GIA models.
Global Positioning System (GPS) time series offer important constraints on GIA and, indeed, have been installed in many of the critical locations. However, the current network of GPS sites, whilst useful in discriminating between major differences in contemporary GIA models, is too sparse to provide the constraints required to significantly reduce the GIA uncertainty in the GRACE signal – for that a high spatial resolution of GPS sites is required. In particular, the southern Antarctic Peninsula/Ronne Ice Shelf contains a very large GRACE signal, but the current station density there is too sparse to unambiguously determine the origin of the gravity change. Further rock outcrops suitable for additional data collection are available in this region and situating there new, more densely spaced, continuous sites would provide the required constraints. Here, we propose to develop improved models of West Antarctic GIA through newly collected GPS-data, thereby allowing us to compute new accurate and precise estimates of ice mass contributions to sea level rise from West Antarctica.
This is a NERC-funded project, led by Matt King (Newcastle) but involving close collaboration with researchers at BAS, University of Ottawa and Ohio State University. GPS receivers collected data between seasons 2009/10 and 2013/14. These data are being processed, and a suite of GIA models being run.