Abstract
AbstractWe map recent Greenland Ice Sheet elevation change at high spatial (5 km) and temporal (monthly) resolution using CryoSat‐2 altimetry. After correcting for the impact of changing snowpack properties associated with unprecedented surface melting in 2012, we find good agreement (3 cm/yr bias) with airborne measurements. With the aid of regional climate and firn modeling, we compute high spatial and temporal resolution records of Greenland mass evolution, which correlate (R = 0.96) with monthly satellite gravimetry and reveal glacier dynamic imbalance. During 2011–2014, Greenland mass loss averaged 269 ± 51 Gt/yr. Atmospherically driven losses were widespread, with surface melt variability driving large fluctuations in the annual mass deficit. Terminus regions of five dynamically thinning glaciers, which constitute less than 1% of Greenland's area, contributed more than 12% of the net ice loss. This high‐resolution record demonstrates that mass deficits extending over small spatial and temporal scales have made a relatively large contribution to recent ice sheet imbalance.
Highlights
Since the early 1990s, mass loss from the Greenland Ice Sheet has contributed approximately 10% of the observed global mean sea level rise [Vaughan et al, 2013]
The high spatial resolution and comprehensive coverage provided by CryoSat-2 provides a detailed map of ice sheet mass balance, showing widespread ice loss at lower elevations, along the western margin, with the highest rates of change located across several distinct glacier systems (Figure 1)
These findings, which are supported by the RACMO2.3 simulations (Figure 1), provide observational evidence that atmospheric conditions are affecting the far north of the ice sheet
Summary
Since the early 1990s, mass loss from the Greenland Ice Sheet has contributed approximately 10% of the observed global mean sea level rise [Vaughan et al, 2013] During this period, the ice imbalance has increased with time [Rignot et al, 2011; Shepherd et al, 2012], as warmer atmospheric conditions have prevailed [Hanna et al, 2008; Fettweis et al, 2013a, 2013b] and many marine-terminating glaciers have accelerated [Joughin et al, 2010; Moon et al, 2012; Enderlin et al, 2014]. The high spatial and temporal variability in Greenland glacier behavior complicates extrapolation of recent observations forward in time and reinforces the need to develop process-based projections of ice sheet evolution.
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