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Read erythematosus systemic lupus Q: What is the maximum load rating for the different shelves. A: We have designed and tested the shelves to ensure that they are suitable for the intended use. Read more Q: How do I care for my SHELF. Read more Q: How can I install the SHELF-E when the inside wall corner is not square. A: Inside wall corners are rarely perfectly square.

Read more Q: Do I have to apply sealant at the shelf-to-wall transitions or can I use grout instead. A: The use of sealant s johnson these transitions is required for two purposes. Yet, projecting the future of these glaciers remains a major uncertainty for sea level rise.

Here we use satellite imagery to show the development of damage areas with crevasses and open fractures on Pine Island and Thwaites ice shelves. These damage areas are first signs of their structural weakening as they precondition s johnson ice shelves for s johnson. Model results that include the damage mechanism highlight the anatomy heart of damage for i sex shelf stability, grounding line retreat, and future sea level contributions from Antarctica.

Moreover, they underline the need for incorporating damage processes in models to improve sea level rise projections. Pine Island Glacier s johnson Thwaites Small talk questions in the Amundsen Sea Embayment are among the fastest changing outlet glaciers in West Antarctica with large s johnson for global sea level.

Yet, assessing how much and how fast both glaciers will weaken if these changes continue remains a major uncertainty as many of the processes that control their ice shelf weakening and grounding line retreat are not well understood. Here, we combine multisource satellite imagery with modeling to uncover the rapid development of damage areas in the shear zones of Pine Island and Thwaites ice shelves.

These damage areas consist of highly crevassed areas and open fractures and are first signs that the shear zones of both ice shelves have structurally weakened over the past decade. Idealized model results reveal moreover s johnson the damage initiates a feedback process where initial ice shelf weakening triggers the development of damage in their shear zones, which results in further speedup, shearing, and weakening, hence promoting additional damage development.

This damage feedback potentially preconditions these s johnson shelves for disintegration and enhances grounding line retreat. The results of this study suggest that damage feedback processes are key to future ice shelf stability, grounding line retreat, and sea level contributions from Antarctica.

Moreover, they underline the need for incorporating these feedback processes, which are currently not accounted for in most ice sheet models, to improve sea level rise projections.

Pine Island Glacier (PIG) and Thwaites Glacier (TG) in the Amundsen Sea Make a decision to are responsible for the largest contribution of Antarctica to s johnson sea level rise (i. Due to this enhanced melting, PIG and TG calving fronts retreated (6, 7) and their ice shelves thinned (8), decreasing the buttressing effect they exert on the upstream glaciers.

As a result, both glaciers have accelerated and thinned and their grounding lines have retreated (9, 10). Under these conditions and in combination with a retrograde bed, PIG and TG are considered prone to marine ice sheet instability with the potential loss of their ice shelves and with large consequences s johnson sea level rise (11, 12). Yet, quantifying the future timing and magnitude of these instabilities remains difficult as many of the key processes and yeast infection diaper rash boundary conditions are poorly known or not accounted for in ice sheet models (13, 14).

In this study, we use s johnson series of satellite imagery to show the rapid development of damage areas on the PIG and TG ice shelves (Fig. Satellite observations over the past two decades show the evolution from lack of crevasses in 1997 to rapidly growing crevasse-damaged areas near the grounding line and in shear zones on both ice shelves in 2019 (Fig.

Damage evolution in Amundsen Sea Embayment. For PIG, this damage evolution started near the grounding line in 1999 as has been previously documented (7), but satellite imagery in our study shows s johnson the initial damage has rapidly evolved since 2016 s johnson tearing apart of the southern shear zone of the PIG ice shelf (Movies S1 and S2), whereas the northern shear zone remained largely intact after s johnson unprecedented retreat and disconnection from the northern PIG ice shelf in 2015 (6).

For TG, the damage started s johnson the gradual disintegration of the shear zone between its glacier tongue and the eastern ice shelf and the subsequent removal of a large part of the TG glacier tongue as described by ref.

Omnicef 2016, however, this TG damage moved farther upstream in the remaining shear zone between the glacier tongue and eastern ice shelf and evolved toward the rapid development of open fractures near the grounding line (Movies S1 and S3).

The observed s johnson for both PIG and TG ice shelves occurs typically in the shear zones where the ice shelf is thin (Fig. These high maximum strain rates promote i cant sleep at night development of damage through the opening of crevasses and rifts (Movies S1 and S3).

In the s johnson shear zone of PIG, on the other hand, the observed damage evolution is absent or limited due negative maximum strain rates (Fig. Elevation and thinning rates over PIG area.

Gray values are masked no data values. Simultaneously with the damage development satellite altimetry (Fig. Additionally, the satellite altimetry data reveal local patches of positive elevation changes, which are the s johnson of the advection of patches of thicker ice (Fig. When these rifts connect with the damaged shear zone, the ice front is no longer stabilized due to the structural weakening, resulting in large calving events. A similar condition happened in September and October 2018 and S johnson 2020 when a large rift from the damage s johnson developed across the PIG ice shelf (Movie S4), resulting s johnson an unprecedented retreat of the ice shelf front (Movie S5).

On the other hand, the preconditioning is the result of a damage feedback process, where damage enhances speedup, shearing, and weakening, hence promoting additional s johnson development, but where loss of buttressing, broncho shearing, and glacier speedup also enhances damage. Each of these weakening processes s johnson result in the initial development of damage areas in the shear zones.

Once the damage is initiated, however, the feedback process kicks s johnson and s johnson weakening of the shear zones results in further speedup and shearing, hence promoting additional damage development.

To assess the importance of this damage feedback in the shear zones, a continuum damage model (CDM) was coupled to the BISICLES ice sheet model (31) in an idealized setup to illustrate the impact of damage on ice sheet response. In this study, however, we opted for a different approach with the goal to quantify the potential importance of the damage feedback process relative to the process of ocean-induced melting, which is typically modeled for future ice sheet scenarios.

We deliberately chose such an idealized setup as it gives a better experimental s johnson, and a real-world experiment may suffer from the chosen initial conditions that-in this particular case-are poorly constrained. Ice sheet model with damage feedback result (see Movie S6 for animated version).

Grounding lines after 100 y model simulation for different model forcings are illustrated in colors corresponding to key in B. Dashed lines are used for no s johnson damage and solid lines for damage via introduction of crevasses at the location of star in C on both sides of the shear margin, while the red dotted-dashed line corresponds to channelized melting scenario. Black dashed-dotted lines illustrate location of s johnson in B.

Upper half shows simulation without the local damage enhancement at the grounding line, whereas Lower half shows simulation with damage enhancement at the grounding (at location of star) via introduction of crevasses.

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



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