Increased West Antarctic ice discharge and East Antarctic stability over the last 
seven years

Gardner, Alex; Moholdt, Geir; Scambos, T. A.; Fahnstock, Mark; Ligtenberg, Stefan; Broeke, Michiel van den; Nilsson, Johan

doi:10.5194/tc-2017-75

Cited by 6 publications

(8 citation statements)

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“…Finally, changes in cloud phase and structure over Antarctica, sea ice decline, and ocean surface warming have been suggested to control AIS SMB into the future (Lenaerts et al, ). The projected Antarctic SMB increase is expected to mitigate some fraction of the currently ongoing dynamic mass loss in West Antarctica, which is about 200 Gt/year (Gardner et al, ; Shepherd et al, ). While the consensus is that dynamic losses will dominate future AIS MB, especially in marine sectors of the ice sheet in West Antarctica, the Antarctic Peninsula, and some portions of East Antarctica, some other parts of the AIS are likely to experience mass gain by enhanced snowfall, as long as surface runoff remains small (Winkelmann et al, ).…”

Section: Future Ice Sheet Smb: Projections Feedbacks Uncertaintiesmentioning

confidence: 99%

Observing and Modeling Ice Sheet Surface Mass Balance

Lenaerts

Medley

Broeke

et al. 2019

Reviews of Geophysics

Self Cite

164

152

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Surface mass balance (SMB) provides mass input to the surface of the Antarctic and Greenland Ice Sheets and therefore comprises an important control on ice sheet mass balance and resulting contribution to global sea level change. As ice sheet SMB varies highly across multiple scales of space (meters to hundreds of kilometers) and time (hourly to decadal), it is notoriously challenging to observe and represent in models. In addition, SMB consists of multiple components, all of which depend on complex interactions between the atmosphere and the snow/ice surface, large‐scale atmospheric circulation and ocean conditions, and ice sheet topography. In this review, we present the state‐of‐the‐art knowledge and recent advances in ice sheet SMB observations and models, highlight current shortcomings, and propose future directions. Novel observational methods allow mapping SMB across larger areas, longer time periods, and/or at very high (subdaily) temporal frequency. As a recent observational breakthrough, cosmic ray counters provide direct estimates of SMB, circumventing the need for accurate snow density observations upon which many other techniques rely. Regional atmospheric climate models have drastically improved their simulation of ice sheet SMB in the last decade, thanks to the inclusion or improved representation of essential processes (e.g., clouds, blowing snow, and snow albedo), and by enhancing horizontal resolution (5–30 km). Future modeling efforts are required in improving Earth system models to match regional atmospheric climate model performance in simulating ice sheet SMB, and in reinforcing the efforts in developing statistical and dynamic downscaling to represent smaller‐scale SMB processes.

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Section: Future Ice Sheet Smb: Projections Feedbacks Uncertaintiesmentioning

confidence: 99%

Observing and Modeling Ice Sheet Surface Mass Balance

Lenaerts

Medley

Broeke

et al. 2019

Reviews of Geophysics

Self Cite

164

152

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“…1c) in 1974and 1996from Doake (1975 and Rignot et al (2005). The ice velocities at Station A and C in 2008 are from Wendt et al (2010) and in 2015 were derived from Landsat 8 data (Gardner et al, 2017).…”

Section: Figurementioning

confidence: 99%

Rapid ice unloading in the Fleming Glacier region, southern Antarctic Peninsula, and its effect on bedrock uplift rates

Zhao

King

Watson

et al. 2017

Earth and Planetary Science Letters

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“…B2 for the Filchner-Ronne Ice Shelf. In this case, inversion was done for element-based basal slipperiness and ice softness (instead of inverting on a nodal basis) using a Bayesian methodology (instead of Tikhonov regularization) and the MEASURES velocity data set (Rignot et al (2011) instead of Landsat 8 (Gardner et al, 2017)). This setup is further described in Reese et al (2017).…”

Section: Appendix B: Consistent Results Using Different Model Parametersmentioning

confidence: 99%

“…2) and ice softness fields A (see Eq. 3) to match observed 2015/2016 velocities derived from Landsat 8 imagery (Gardner et al, 2017). The stress exponent of Glen's flow law was set to n = 3 and we repeated the inversion for a whole sequence of sliding law exponents m = 1, 2, 3, 4, 5, 7, 9, 11.…”

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confidence: 99%

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Grounding-line flux formula applied as a flux condition in numerical simulations fails for buttressed Antarctic ice streams

Reese¹,

Winkelmann²,

Gudmundsson³

2018

Preprint

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Abstract. Currently, several large-scale ice-flow models impose a condition on ice-flux across grounding lines using an analytically motivated parameterization of grounding-line flux. It has been suggested that employing this analytical expression alleviates the need for highly resolved computational domains around grounding lines of marine ice sheets. While the analytical flux formula is expected to be accurate in an unbuttressed flow-line setting, its validity has hitherto not been assessed for complex and realistic geometries such as those of the Antarctic Ice Sheet. Here the accuracy of this analytical flux formula 5 is tested against an optimized ice flow model that uses a highly-resolved computational mesh around the Antarctic grounding lines. We find that when applied to the Antarctic Ice Sheet the analytical expression provides inaccurate estimates of ice fluxes for almost all grounding lines. Furthermore, in many instances direct application of the analytical formula gives rise to unphysical complexed-valued ice fluxes. We conclude that grounding lines of the Antarctic Ice Sheet are, in general, too highly buttressed for the analytical parameterization to be of practical value for the calculation of grounding-line fluxes.

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Increased West Antarctic ice discharge and East Antarctic stability over the last seven years

Abstract: Ice discharge from large ice sheets plays a direct role in determining rates of sea level rise. We map present-day Antarctic- The Cryosphere Discuss.,

Cited by 6 publications

References 50 publications

Observing and Modeling Ice Sheet Surface Mass Balance

Observing and Modeling Ice Sheet Surface Mass Balance

Rapid ice unloading in the Fleming Glacier region, southern Antarctic Peninsula, and its effect on bedrock uplift rates

Grounding-line flux formula applied as a flux condition in numerical simulations fails for buttressed Antarctic ice streams

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