An assessment of key model parametric uncertainties in projections of Greenland Ice Sheet behavior
Lack of knowledge about the values of ice sheet model input parameters introduces substantial uncertainty into projections of Greenland Ice Sheet contributions to future sea level rise. Computer models of ice sheet behavior provide one of several means of estimating future sea level rise due to mass...
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fthokunivhus:oai:eprints.lib.hokudai.ac.jp:2115/49381 2023-05-15T16:26:36+02:00 An assessment of key model parametric uncertainties in projections of Greenland Ice Sheet behavior Applegate, Patrick J. Kirchner, Nina Stone, Emma J. Keller, Klaus Greve, Ralf http://hdl.handle.net/2115/49381 https://doi.org/10.5194/tc-6-589-2012 eng eng Copernicus Publications http://hdl.handle.net/2115/49381 The Cryosphere, 6(3): 589-606 http://dx.doi.org/10.5194/tc-6-589-2012 http://creativecommons.org/licenses/by/3.0/ CC-BY Greenland ice sheet Uncertainty Input parameter Climate change Ice sheet modelling 452 article fthokunivhus https://doi.org/10.5194/tc-6-589-2012 2022-11-18T01:02:25Z Lack of knowledge about the values of ice sheet model input parameters introduces substantial uncertainty into projections of Greenland Ice Sheet contributions to future sea level rise. Computer models of ice sheet behavior provide one of several means of estimating future sea level rise due to mass loss from ice sheets. Such models have many input parameters whose values are not well known. Recent studies have investigated the effects of these parameters on model output, but the range of potential future sea level increases due to model parametric uncertainty has not been characterized. Here, we demonstrate that this range is large, using a 100-member perturbed-physics ensemble with the SICOPOLIS ice sheet model. Each model run is spun up over 125000 yr using geological forcings and subsequently driven into the future using an asymptotically increasing air temperature anomaly curve. All modeled ice sheets lose mass after 2005 AD. Parameters controlling surface melt dominate the model response to temperature change. After culling the ensemble to include only members that give reasonable ice volumes in 2005 AD, the range of projected sea level rise values in 2100 AD is ~40% or more of the median. Data on past ice sheet behavior can help reduce this uncertainty, but none of our ensemble members produces a reasonable ice volume change during the mid-Holocene, relative to the present. This problem suggests that the model's exponential relation between temperature and precipitation does not hold during the Holocene, or that the central-Greenland temperature forcing curve used to drive the model is not representative of conditions around the ice margin at this time (among other possibilities). Our simulations also lack certain observed physical processes that may tend to enhance the real ice sheet's response. Regardless, this work has implications for other studies that use ice sheet models to project or hindcast the behavior of the Greenland Ice Sheet. Article in Journal/Newspaper Greenland Ice Sheet The Cryosphere Hokkaido University Collection of Scholarly and Academic Papers (HUSCAP) Greenland The Cryosphere 6 3 589 606 |
institution |
Open Polar |
collection |
Hokkaido University Collection of Scholarly and Academic Papers (HUSCAP) |
op_collection_id |
fthokunivhus |
language |
English |
topic |
Greenland ice sheet Uncertainty Input parameter Climate change Ice sheet modelling 452 |
spellingShingle |
Greenland ice sheet Uncertainty Input parameter Climate change Ice sheet modelling 452 Applegate, Patrick J. Kirchner, Nina Stone, Emma J. Keller, Klaus Greve, Ralf An assessment of key model parametric uncertainties in projections of Greenland Ice Sheet behavior |
topic_facet |
Greenland ice sheet Uncertainty Input parameter Climate change Ice sheet modelling 452 |
description |
Lack of knowledge about the values of ice sheet model input parameters introduces substantial uncertainty into projections of Greenland Ice Sheet contributions to future sea level rise. Computer models of ice sheet behavior provide one of several means of estimating future sea level rise due to mass loss from ice sheets. Such models have many input parameters whose values are not well known. Recent studies have investigated the effects of these parameters on model output, but the range of potential future sea level increases due to model parametric uncertainty has not been characterized. Here, we demonstrate that this range is large, using a 100-member perturbed-physics ensemble with the SICOPOLIS ice sheet model. Each model run is spun up over 125000 yr using geological forcings and subsequently driven into the future using an asymptotically increasing air temperature anomaly curve. All modeled ice sheets lose mass after 2005 AD. Parameters controlling surface melt dominate the model response to temperature change. After culling the ensemble to include only members that give reasonable ice volumes in 2005 AD, the range of projected sea level rise values in 2100 AD is ~40% or more of the median. Data on past ice sheet behavior can help reduce this uncertainty, but none of our ensemble members produces a reasonable ice volume change during the mid-Holocene, relative to the present. This problem suggests that the model's exponential relation between temperature and precipitation does not hold during the Holocene, or that the central-Greenland temperature forcing curve used to drive the model is not representative of conditions around the ice margin at this time (among other possibilities). Our simulations also lack certain observed physical processes that may tend to enhance the real ice sheet's response. Regardless, this work has implications for other studies that use ice sheet models to project or hindcast the behavior of the Greenland Ice Sheet. |
format |
Article in Journal/Newspaper |
author |
Applegate, Patrick J. Kirchner, Nina Stone, Emma J. Keller, Klaus Greve, Ralf |
author_facet |
Applegate, Patrick J. Kirchner, Nina Stone, Emma J. Keller, Klaus Greve, Ralf |
author_sort |
Applegate, Patrick J. |
title |
An assessment of key model parametric uncertainties in projections of Greenland Ice Sheet behavior |
title_short |
An assessment of key model parametric uncertainties in projections of Greenland Ice Sheet behavior |
title_full |
An assessment of key model parametric uncertainties in projections of Greenland Ice Sheet behavior |
title_fullStr |
An assessment of key model parametric uncertainties in projections of Greenland Ice Sheet behavior |
title_full_unstemmed |
An assessment of key model parametric uncertainties in projections of Greenland Ice Sheet behavior |
title_sort |
assessment of key model parametric uncertainties in projections of greenland ice sheet behavior |
publisher |
Copernicus Publications |
url |
http://hdl.handle.net/2115/49381 https://doi.org/10.5194/tc-6-589-2012 |
geographic |
Greenland |
geographic_facet |
Greenland |
genre |
Greenland Ice Sheet The Cryosphere |
genre_facet |
Greenland Ice Sheet The Cryosphere |
op_relation |
http://hdl.handle.net/2115/49381 The Cryosphere, 6(3): 589-606 http://dx.doi.org/10.5194/tc-6-589-2012 |
op_rights |
http://creativecommons.org/licenses/by/3.0/ |
op_rightsnorm |
CC-BY |
op_doi |
https://doi.org/10.5194/tc-6-589-2012 |
container_title |
The Cryosphere |
container_volume |
6 |
container_issue |
3 |
container_start_page |
589 |
op_container_end_page |
606 |
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1766015539540393984 |