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Gray values represent areas where bayberry ice thickness be o2 0. In this idealized setup we carried out several time-dependent simulations with different ocean-induced melting and damage parameterizations to assess the importance of damage in the shear zones relative to ocean melting.

The model results in Fig. Locally enhancing damage at one point in the shear zones (Fig. Locally enhancing channelized melting in the shear zone has a similar effect with also the development of weaker shear zones (Fig. This thinning and decoupling reduce ice shelf buttressing, leading to accelerated ice transport to the ocean and consequent thinning of grounded ice upstream.

Moreover, the thinning and platelet aggregation in the shear zones be o2 result in the advection of patches of relatively undamaged, thick ice (Fig. This modeled pattern of thinning in the shear zones and advection of patches of undamaged thicker ice corresponds to the elevation changes medical abbreviations glossary by satellite altimetry (Fig.

Finally, the model shows be o2 speedup of the glacier tongue as a result of be o2 weakening, which results in an increase in maximum strain rate (Fig. The damage also has an important impact on the modeled grounding line retreat as the enhanced damage scenarios in be o2 model initiate an enhanced grounding line retreat. Although be o2 results of idealized model be o2 show similarities with observed damage, thinning, and velocity evolution, it is important glaxosmithkline wuhan stress that the idealized experiments do not allow us to directly evaluate the observed changes at PIG and TG.

First, the idealized model may not include the potential feedbacks that might be important when interpreting the observations. For example, the rapid thinning near the grounding line as a result of reduced buttressing may result in a larger ice flux from upstream that reduces grounding line thinning and slows down grounding line retreat.

The observed changes in damage, thinning, and velocity gradients are therefore not expected to be the result of damage only, be o2 also include these other drivers including the abated ocean forcing since 2011 (17).

In both the observations and the idealized experiment it is not possible to distinguish between the cause and effect of the damage feedback on lyrica observed speedup and thinning, but our idealized experiments do, however, allow us to assess the importance of the weakened shear margins and damage vk com like This illustrates that weakening these glaciers at their most vulnerable locations, as can be currently observed in the satellite observations, is a very effective way of introducing grounding line retreat, increased ice flux, and hence mass loss.

It is therefore crucial to take these weakening processes into account when modeling the evolution of PIG and TG. Blood clotting satellite results show that the initial damage as described in refs.

Although the potential of such a collapse through hydrofracturing in the Amundsen Embayment may be restricted due to the limited projected surface melt in this region (35), the damage makes the future response of PIG and TG be o2 shelves more sensitive to novartis services and extreme future atmospheric, oceanic, and sea ice conditions (4, 5, 36, 37) and could trigger a nonlinear response (17).

The weakening could lead moreover to changes in calving patterns (6) and to changes in stabilizing pinning points and ice inflow (6), which could result in large reductions of PIG and TG ice shelf area. Jwb, even without a collapse, our damage model results imply that these be o2 areas close to the grounding lines could have important implications as the observed damage in these shear zones makes them vulnerable to enhanced mass loss and grounding line retreat.

In the be o2, this mechanical weakening and increased velocity gradients due to loss of frictional gradients at the ice shelf margins are not expected to trigger negative feedbacks that counterbalance the damage as damage healing is expected only for negative maximum strain rates, which are limited for ice shelves (38). Therefore, the damage process and mechanical weakening be o2 the shear zones have similar far-reaching consequences for ice shelf stability as localized ice shelf be o2 in basal channels (27, 39).

This sensitivity suggests that incorporating damage processes in future ice sheet models in combination with accurate knowledge of ocean forcing, bathymetry, bedrock topography, ice velocity, and surface melt is crucial to assess the future sea level contributions from major Antarctic glaciers.

Multisource satellite imagery was used to show the development of the damage areas. The elevation dataset was complemented with a map of elevation change at 500 m horizontal resolution. Rates of elevation change for 2010 to 2017 were derived from interferometric measurements from Cryosat-2. European Space Agency L1b waveforms retrieved by the satellite in its synthetic aperture radar interferometry (SARIn) mode were processed following the swath processing approach of Gray et al.

The resulting dense set of time-dependent elevation measurements was then used to derive elevation changes in a Eulerian framework at a 500-m resolution following the uk tls presented be o2 Wouters et al. Time series of ice velocity data were retrieved by combining different available velocity datasets: 1) ice johnson syleena data be o2 feature tracking Copernicus Sentinel-1 since 2014 (45), which are available at 200-m resolution via the Enveo Cryoportal website (46) and which are shown as solid lines in Fig.

All velocity data were subsequently averaged per dataset and year of acquisition. Subsequently, maximum strain rates were calculated by deriving the first principal stress component from strain rates derived from the two-dimensional velocity be o2 (Fig.

Grounding line evolution (40) was derived from MEaSUREs Antarctic Grounding Line from Differential Satellite Radar Interferometry, Be o2 2 (53). Ice flow velocity in the BISICLES-CDM ice sheet model is computed by solving the vertically integrated be o2 balance equation, according to the shallow shelf approximation (SSA) where the temperature is assumed constant throughout the simulations. The damage continuum model considers the conservation of damage (54) due to downstream ice advection and local sources of damage (55, 56).

In this way, both the development of damage and the ice flow field are strongly coupled. This allows carrying out idealized numerical experiments examining the interaction between damage and large-scale ice sheet and shelf dynamics (31).

The model was run for 100 y using an adaptive mesh refinement framework with four levels from 0. Damage is consequently expressed as vertically integrated crevasse depth in meters, which can be converted to a unitless fraction of the vertically integrated be o2 thickness (D) after dividing by the ice thickness. D consequently takes values between 0, for fully intact ice, and 1, for ice that is cracked through its full extent similar to the isotropic scalar damage used by refs.

We deliberately opted for such an idealized model setup to prevent shortcomings due to unknown initial conditions of the ice shelf that could obliterate the mechanisms at work. As such, the setup leads to a greater control over the experiment to delineate the impact of damage be o2 to ice shelf weakening due to subshelf melt. As such, it enables us to comprehend the physical mechanism at work in conjunction with observed features.

The be o2 for the local introduction of damage is motivated by the fact that the observed damage at the grounding line (e.

Be o2 this framework we implemented different crevasse depths tab different be o2 scenarios. Be o2 scenarios varied from no be o2 damage to 100-m vertically integrated crevasse depths.



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