Geodetic and model data reveal different spatio-temporal patterns of transient mass changes over Greenland from 2007 to 2017

• Published in: Earth and Planetary Science Letters
• Main Authors: Zhang, Bao, Liu, Lin, Khan, Shfaqat Abbas, Dam, Tonie van, Bjørk, Anders Anker, Peings, Yannick, Zhang, Enze, Bevis, Michael, Yao, Yibin, Noël, Brice
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2019
• Subjects: Greenland; Transient mass change; GRACE; GPS; SMB; Ice discharge; /dk/atira/pure/sustainabledevelopmentgoals/climate_action; name=SDG 13 - Climate Action; Ice Sheet
• Online Access: https://orbit.dtu.dk/en/publications/d4f47744-810d-4894-9455-0bc8c6588c1d; https://doi.org/10.1016/j.epsl.2019.03.028; https://backend.orbit.dtu.dk/ws/files/171575175/marac_1_s2.0_S0012821X19301761_main.pdf

Much of the research to understand the ice mass changes of Greenland ice sheet (GrIS) has focused on detecting linear rates and accelerations at decadal or longer periods. The transient (short-term, non-secular) mass changes show large variability, and if not properly accounted for, can introduce significant biases into estimates of long-term ice mass loss rates and accelerations. Despite the growing number of geodetic observations, in terms of spatial coverage, types of observables, and the extent of the time series, studies of the transient mass changes over GrIS are lacking. To address this limitation, we apply multi-channel singular spectral analysis to the Gravity Recovery and Climate Experiment (GRACE) mass concentrations (mascon), surface mass balance (SMB) model output, and ice discharge data, to determine the transient mass changes over Greenland over the decade (2007 to 2017). The goal of this analysis is to elucidate the spatio-temporal variability of the ice mass change. For the entire GrIS, both the mascon and SMB transient mass changes are characterized by a sustained mass gain from late 2007 to early 2010, a sustained mass loss from early 2010 to early 2013, and a mass gain from early 2013 to mid-2015. Global Positioning System sites deployed along the coast of Greenland showed uplift from early 2010 to early 2013 and subsidence from early 2013 to 2015, consistent with the corresponding ice mass loss and gain of the entire GrIS. The peak-to-peak amplitude of the transient mass change was estimated to be −294 ± 27 Gt from GRACE mascons and -252 ± 16 Gt from the SMB where the latter value includes the effect of ice discharge. The transient mass change due to ice discharge accounted for less than 10% of the total transient mass change. Our regional assessment reveals that the central-west, southwest, northeast, and southeast regions display similar time-varying patterns as we found for the entire GrIS, but the north and northwest regions show different patterns. Atmospheric circulation anomalies as ...