Transient variations in ice mass near Jakobshavn Isbræ (west Greenland) detected by the combined use of GPS and GRACE data
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AbstractJakobshavn Isbræ (JI) in west Greenland has been undergoing dramatic ice loss in the past decade. The Global Positioning System (GPS) sites deployed nearby JI and the Gravity Recovery and Climate Experiment (GRACE) provide independent datasets that can be used to monitor and quantify ice mass changes. Here we apply the Multichannel Singular Spectral Analysis (M-SSA) to the combination of GPS (both vertical and horizontal displacements) and GRACE data to separate transient signals from the original noisy GPS data and coarse-resolution GRACE data. We also forward model the transient changes of loading displacements due to changes in ice discharge and surface mass balance (SMB). We perform a fluxgate calculation using velocity maps produced by satellite Synthetic Aperture Radar images to quantify the dynamically-induced mass loss and its temporal changes. We distribute the ice discharge spatially over ice fields according to dynamically induced elevation change. We use the modeled SMB from RACMO (version 2.3) to model SMB-induced loading displacements. The forward modeling results show that: (1) Ice discharge in JI underwent strong seasonal changes and the amplitudes become significantly larger in recent years; (2) the transient signals detected during mid-2008 and 2015 were due to the combined contribution from ice discharge and SMB, but SMB contributes more than ice discharge; and (3) there is a phase difference between the forward modeled displacements and the GPS-and-GRACE-inferred displacements, which may be due to that the shorter time span of modeled displacements and inaccuracy in the modeling.
Acceptance Date13/06/2017
All Author(s) ListEnze ZHANG,Shfaqat A. Khan, Tonie van Dam, Lin Liu, Bao Zhang
Name of ConferenceWorkshop on Glacial Isostatic Adjustment and Elastic Deformation
Start Date of Conference05/09/2017
End Date of Conference07/09/2017
Place of ConferenceGrand Hotel Reykjavik, Iceland
Country/Region of ConferenceIceland
Year2017
LanguagesEnglish-United States

Last updated on 2018-23-01 at 02:45