Probabilistic parameterisation of the surface mass balance–elevation feedback in regional climate model simulations of the Greenland ice sheet
We present a new parameterisation that relates surface mass balance (SMB: the sum of surface accumulation and surface ablation) to changes in surface elevation of the Greenland ice sheet (GrIS) for the MAR (Modèle Atmosphérique Régional: Fettweis, 2007) regional climate model. The motivation is to d...
| Main Authors: | , , , , , , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2014-01-01
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| Series: | The Cryosphere |
| Online Access: | http://www.the-cryosphere.net/8/181/2014/tc-8-181-2014.pdf |
| _version_ | 1811305220457627648 |
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| author | T. L. Edwards X. Fettweis O. Gagliardini F. Gillet-Chaulet H. Goelzer J. M. Gregory M. Hoffman P. Huybrechts A. J. Payne M. Perego S. Price A. Quiquet C. Ritz |
| author_facet | T. L. Edwards X. Fettweis O. Gagliardini F. Gillet-Chaulet H. Goelzer J. M. Gregory M. Hoffman P. Huybrechts A. J. Payne M. Perego S. Price A. Quiquet C. Ritz |
| author_sort | T. L. Edwards |
| collection | DOAJ |
| description | We present a new parameterisation that relates surface mass balance (SMB: the
sum of surface accumulation and surface ablation) to changes in surface
elevation of the Greenland ice sheet (GrIS) for the MAR (Modèle Atmosphérique
Régional: Fettweis, 2007) regional climate
model. The motivation is to dynamically adjust SMB as the GrIS evolves,
allowing us to force ice sheet models with SMB simulated by MAR while
incorporating the SMB–elevation feedback, without the substantial technical
challenges of coupling ice sheet and climate models. This also allows us to
assess the effect of elevation feedback uncertainty on the GrIS contribution
to sea level, using multiple global climate and ice sheet models, without the
need for additional, expensive MAR simulations.
<br><br>
We estimate this relationship separately below and above the equilibrium line
altitude (ELA, separating negative and positive SMB) and for regions north
and south of 77° N, from a set of MAR simulations in which we alter
the ice sheet surface elevation. These give four "SMB lapse rates",
gradients that relate SMB changes to elevation changes. We assess
uncertainties within a Bayesian framework, estimating probability
distributions for each gradient from which we present best estimates and
credibility intervals (CI) that bound 95% of the probability. Below the
ELA our gradient estimates are mostly positive, because SMB usually increases
with elevation: 0.56 (95% CI: −0.22 to 1.33) kg m<sup>−3</sup> a<sup>−1</sup> for
the north, and 1.91 (1.03 to 2.61) kg m<sup>−3</sup> a<sup>−1</sup> for the south.
Above the ELA, the gradients are much smaller in magnitude: 0.09 (−0.03 to
0.23) kg m<sup>−3</sup> a<sup>−1</sup> in the north, and 0.07 (−0.07 to
0.59) kg m<sup>−3</sup> a<sup>−1</sup> in the south, because SMB can either increase
or decrease in response to increased elevation.
<br><br>
Our statistically founded approach allows us to make probabilistic
assessments for the effect of elevation feedback uncertainty on sea level
projections (Edwards et al., 2014). |
| first_indexed | 2024-04-13T08:21:28Z |
| format | Article |
| id | doaj.art-a6208acf7d4a486eb6dbb6703f3b2e41 |
| institution | Directory Open Access Journal |
| issn | 1994-0416 1994-0424 |
| language | English |
| last_indexed | 2024-04-13T08:21:28Z |
| publishDate | 2014-01-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | The Cryosphere |
| spelling | doaj.art-a6208acf7d4a486eb6dbb6703f3b2e412022-12-22T02:54:38ZengCopernicus PublicationsThe Cryosphere1994-04161994-04242014-01-018118119410.5194/tc-8-181-2014Probabilistic parameterisation of the surface mass balance–elevation feedback in regional climate model simulations of the Greenland ice sheetT. L. Edwards0X. Fettweis1O. Gagliardini2F. Gillet-Chaulet3H. Goelzer4J. M. Gregory5M. Hoffman6P. Huybrechts7A. J. Payne8M. Perego9S. Price10A. Quiquet11C. Ritz12Department of Geographical Sciences, University of Bristol, Bristol BS8 1SS, UKDepartment of Geography, University of Liege, Laboratory of Climatology (Bat. B11), Allée du 6 Août, 2, 4000 Liège, BelgiumLaboratoire de Glaciologie et Géophysique de l'Environnement, UJF – Grenoble 1/CNRS, 54, rue Molière BP 96, 38402 Saint-Martin-d'Hères Cedex, FranceLaboratoire de Glaciologie et Géophysique de l'Environnement, UJF – Grenoble 1/CNRS, 54, rue Molière BP 96, 38402 Saint-Martin-d'Hères Cedex, FranceEarth System Sciences & Departement Geografie, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, BelgiumNCAS-Climate, Department of Meteorology, University of Reading, Reading, UKFluid Dynamics and Solid Mechanics Group, Los Alamos National Laboratory, T3 MS B216, Los Alamos, NM 87545, USAEarth System Sciences & Departement Geografie, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, BelgiumDepartment of Geographical Sciences, University of Bristol, Bristol BS8 1SS, UKDepartment of Scientific Computing, Florida State University, 400 Dirac Science Library, Tallahassee, FL 32306, USAFluid Dynamics and Solid Mechanics Group, Los Alamos National Laboratory, T3 MS B216, Los Alamos, NM 87545, USALaboratoire de Glaciologie et Géophysique de l'Environnement, UJF – Grenoble 1/CNRS, 54, rue Molière BP 96, 38402 Saint-Martin-d'Hères Cedex, FranceLaboratoire de Glaciologie et Géophysique de l'Environnement, UJF – Grenoble 1/CNRS, 54, rue Molière BP 96, 38402 Saint-Martin-d'Hères Cedex, FranceWe present a new parameterisation that relates surface mass balance (SMB: the sum of surface accumulation and surface ablation) to changes in surface elevation of the Greenland ice sheet (GrIS) for the MAR (Modèle Atmosphérique Régional: Fettweis, 2007) regional climate model. The motivation is to dynamically adjust SMB as the GrIS evolves, allowing us to force ice sheet models with SMB simulated by MAR while incorporating the SMB–elevation feedback, without the substantial technical challenges of coupling ice sheet and climate models. This also allows us to assess the effect of elevation feedback uncertainty on the GrIS contribution to sea level, using multiple global climate and ice sheet models, without the need for additional, expensive MAR simulations. <br><br> We estimate this relationship separately below and above the equilibrium line altitude (ELA, separating negative and positive SMB) and for regions north and south of 77° N, from a set of MAR simulations in which we alter the ice sheet surface elevation. These give four "SMB lapse rates", gradients that relate SMB changes to elevation changes. We assess uncertainties within a Bayesian framework, estimating probability distributions for each gradient from which we present best estimates and credibility intervals (CI) that bound 95% of the probability. Below the ELA our gradient estimates are mostly positive, because SMB usually increases with elevation: 0.56 (95% CI: −0.22 to 1.33) kg m<sup>−3</sup> a<sup>−1</sup> for the north, and 1.91 (1.03 to 2.61) kg m<sup>−3</sup> a<sup>−1</sup> for the south. Above the ELA, the gradients are much smaller in magnitude: 0.09 (−0.03 to 0.23) kg m<sup>−3</sup> a<sup>−1</sup> in the north, and 0.07 (−0.07 to 0.59) kg m<sup>−3</sup> a<sup>−1</sup> in the south, because SMB can either increase or decrease in response to increased elevation. <br><br> Our statistically founded approach allows us to make probabilistic assessments for the effect of elevation feedback uncertainty on sea level projections (Edwards et al., 2014).http://www.the-cryosphere.net/8/181/2014/tc-8-181-2014.pdf |
| spellingShingle | T. L. Edwards X. Fettweis O. Gagliardini F. Gillet-Chaulet H. Goelzer J. M. Gregory M. Hoffman P. Huybrechts A. J. Payne M. Perego S. Price A. Quiquet C. Ritz Probabilistic parameterisation of the surface mass balance–elevation feedback in regional climate model simulations of the Greenland ice sheet The Cryosphere |
| title | Probabilistic parameterisation of the surface mass balance–elevation feedback in regional climate model simulations of the Greenland ice sheet |
| title_full | Probabilistic parameterisation of the surface mass balance–elevation feedback in regional climate model simulations of the Greenland ice sheet |
| title_fullStr | Probabilistic parameterisation of the surface mass balance–elevation feedback in regional climate model simulations of the Greenland ice sheet |
| title_full_unstemmed | Probabilistic parameterisation of the surface mass balance–elevation feedback in regional climate model simulations of the Greenland ice sheet |
| title_short | Probabilistic parameterisation of the surface mass balance–elevation feedback in regional climate model simulations of the Greenland ice sheet |
| title_sort | probabilistic parameterisation of the surface mass balance elevation feedback in regional climate model simulations of the greenland ice sheet |
| url | http://www.the-cryosphere.net/8/181/2014/tc-8-181-2014.pdf |
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