Capturing the interactions between ice sheets, sea level and the solid Earth on a range of timescales: a new “time window” algorithm

Han, Holly Kyeore; Gomez, Natalya; Wan, Jeannette Xiu Wen

doi:10.5194/gmd-15-1355-2022

Cited by 10 publications

(15 citation statements)

References 49 publications

(86 reference statements)

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“…Since the change in GIA signal increases due to fast unloading in a warming climate, smaller time steps of 1000 and 500 years were chosen during the deglaciation. Han et al (2022) showed that coupling time steps of 400 years are optimal for the deglaciation phase using a coupled 1D GIAice-sheet model, but their method assumes a constant topography during one coupling timestep which requires smaller timesteps than the coupling method presented in this study.…”

Section: Size Of the Coupling Time Stepmentioning

confidence: 91%

Simulation of a fully coupled 3D GIA – ice-sheet model for the Antarctic Ice Sheet over a glacial cycle

Calcar

Wal

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et al. 2022

Preprint

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Abstract. Glacial Isostatic Adjustment (GIA) has a stabilizing effect on the evolution of the Antarctic Ice Sheet by reducing the grounding line migration that follows ice melt. The timescale and strength of this feedback depend on the spatially varying viscosity of the Earth’s mantle. Most studies assume a relatively high laterally homogenous response time of the bedrock. However, viscosity is spatially variable with a high viscosity beneath East Antarctica, and a low viscosity beneath West Antarctica. For this study, we have developed a new method to couple a 3D GIA model and an ice-sheet model to study the interaction between the Solid Earth and the Antarctic Ice Sheet during the last glacial cycle. The feedback effect into account on a high temporal resolution by using coupling time steps of 500 years. We applied the method using the ice-sheet model ANICE, a 3D GIA FE model, and results from a seismic model to determine the patterns in the viscosity. The results of simulations over the Last Glacial Cycle show that differences in viscosity of an order of magnitude can lead to differences in grounding line position up to 500 km, to differences in ice thickness in the order of 1.5 km. These results underline and quantify the importance of including local GIA feedback effects in ice-sheet models when simulating the Antarctic Ice Sheet evolution over the Last Glacial Cycle.

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Section: Size Of the Coupling Time Stepmentioning

confidence: 91%

Simulation of a fully coupled 3D GIA – ice-sheet model for the Antarctic Ice Sheet over a glacial cycle

Calcar

Wal

Blank

et al. 2022

Preprint

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“…The sea level code used to generate this data is published in association with Han et al. (2022). Natural Earth country polygons and Pacific boundaries data are available at http://www.naturalearthdata.com.…”

Section: Data Availability Statementmentioning

confidence: 99%

“…To explore possible AIS-sourced SLR impacts at AOSIS locations, we provide new SLR fingerprints under two emissions scenarios spanning three centuries (see Data Availability Statement). Sea level fingerprints associated with a recent projection of the AIS from DeConto et al ( 2021) are generated using a gravitationally self-consistent sea level model that includes viscoelastic deformation, Earth rotational effects and migrating shorelines (Gomez et al, 2010;Han et al, 2022). Sea level predictions are normalized by the global mean sea level equivalent change calculated as in Gomez et al (2010) by distributing meltwater evenly over modern global topography (NOAA, 2009), and allowing for water to inundate areas freed of marine ice.…”

Section: Projections Of Ais Slr For Aosis Locationsmentioning

confidence: 99%

“…Sea level fingerprints associated with a recent projection of the AIS from DeConto et al. (2021) are generated using a gravitationally self‐consistent sea level model that includes viscoelastic deformation, Earth rotational effects and migrating shorelines (Gomez et al., 2010; Han et al., 2022). Sea level predictions are normalized by the global mean sea level equivalent change calculated as in Gomez et al.…”

Section: Antarctic Case Studymentioning

confidence: 99%

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The Paris Agreement and Climate Justice: Inequitable Impacts of Sea Level Rise Associated With Temperature Targets

et al. 2022

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Anthropogenic greenhouse gas emissions are causing unprecedented changes to the climate. In 2015, at the United Nations (UN) Conference of the Parties in Paris, France, countries agreed to limit the global mean temperature (GMT) increase to 2°C above preindustrial levels, and to pursue efforts to limit warming to 1.5°C. Due to the long‐term irreversibility of sea level rise (SLR), risks to island and coastal populations are not well encapsulated by the goal of limiting GMT warming by 2100. This review article investigates the climate justice implications of temperature targets in light of our increasing understanding of the spatially variable impact and long temporal commitment to rising seas. In particular we highlight the impact that SLR will have on island states and the role of the Alliance of Small Island States (AOSIS) in UN climate negotiations. As a case study we review dual impacts from the Antarctic Ice Sheet under a changing climate: (a) recent climate and ice sheet modeling shows that Antarctic melt has the potential to cause rapid SLR with a distinct spatial pattern leading to AOSIS nations experiencing SLR at least 11% higher than the global average and up to 33% higher; and (b) future ice sheet melt will result in a negative feedback on GMT, thus delaying temperature rise. When considering these impacts in conjunction, justice concerns associated with the Paris Agreement are exacerbated.

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“…3-D GIA models such as Latychev et al, 2005, or van der Wal et al, 2015 and be of sufficient spatiotemporal resolution to capture the geometry of grounded ice cover (e.g. Han et al, 2022). Commonly, GIA, ice-sheet and coupled ice-sheet-GIA modelling (e.g.…”

Section: Introductionmentioning

confidence: 99%

Resolving glacial isostatic adjustment (GIA) in response to modern and future ice loss at marine grounding lines in West Antarctica

et al. 2022

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Abstract. Accurate glacial isostatic adjustment (GIA) modelling in the cryosphere is required for interpreting satellite, geophysical and geological records and for assessing the feedbacks of Earth deformation and sea-level change on marine ice-sheet grounding lines. GIA modelling in areas of active ice loss in West Antarctica is particularly challenging because the ice is underlain by laterally varying mantle viscosities that are up to several orders of magnitude lower than the global average, leading to a faster and more localised response of the solid Earth to ongoing and future ice-sheet retreat and necessitating GIA models that incorporate 3-D viscoelastic Earth structure. Improvements to GIA models allow for computation of the viscoelastic response of the Earth to surface ice loading at sub-kilometre resolution, and ice-sheet models and observational products now provide the inputs to GIA models at comparably unprecedented detail. However, the resolution required to accurately capture GIA in models remains poorly understood, and high-resolution calculations come at heavy computational expense. We adopt a 3-D GIA model with a range of Earth structure models based on recent seismic tomography and geodetic data to perform a comprehensive analysis of the influence of grid resolution on predictions of GIA in the Amundsen Sea Embayment (ASE) in West Antarctica. Through idealised sensitivity testing down to sub-kilometre resolution with spatially isolated ice loading changes, we find that a grid resolution of ∼ 13 of the radius of the load or higher is required to accurately capture the elastic response of the Earth. However, when we consider more realistic, spatially coherent ice loss scenarios based on modern observational records and future ice-sheet model projections and adopt a viscoelastic Earth, we find that predicted deformation and sea-level change along the grounding line converge to within 5 % with grid resolutions of 7.5 km or higher, and to within 2 % for grid resolutions of 3.75 km and higher, even when the input ice model is on a 1 km grid. Furthermore, we show that low mantle viscosities beneath the ASE lead to viscous deformation that contributes to the instrumental record on decadal timescales and equals or dominates over elastic effects by the end of the 21st century. Our findings suggest that for the range of resolutions of 1.9–15 km that we considered, the error due to adopting a coarser grid in this region is negligible compared to the effect of neglecting viscous effects and the uncertainty in the adopted mantle viscosity structure.

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Capturing the interactions between ice sheets, sea level and the solid Earth on a range of timescales: a new “time window” algorithm

Cited by 10 publications

References 49 publications

Simulation of a fully coupled 3D GIA – ice-sheet model for the Antarctic Ice Sheet over a glacial cycle

Simulation of a fully coupled 3D GIA – ice-sheet model for the Antarctic Ice Sheet over a glacial cycle

The Paris Agreement and Climate Justice: Inequitable Impacts of Sea Level Rise Associated With Temperature Targets

Resolving glacial isostatic adjustment (GIA) in response to modern and future ice loss at marine grounding lines in West Antarctica

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