MP
M. Petrini
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11 records found
1
Journal article
(2025)
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Thirza Feenstra, Miren Vizcaino, Bert Wouters, Michele Petrini, Raymond Sellevold, Katherine Thayer-Calder
The Greenland ice sheet (GrIS) stores freshwater equal to more than 7 m of potential sea level rise (SLR) and strongly interacts with the Arctic, North Atlantic and global climate. Over the last few decades, the ice sheet has been losing mass at a rate that is projected to increase. Interactions between the GrIS and the climate have the potential to amplify or reduce GrIS mass balance responses to ongoing and projected warming. Here, we investigate the impact of ice sheet–climate interactions on the climate and mass balance of the GrIS using the Community Ice Sheet Model version 2 (CISM2) coupled with the Community Earth System Model version 2 (CESM2). To this end, we compare two idealized multi-century simulations with a non-evolving and evolving ice sheet topography in which we apply an annual 1 % increase in CO2 concentrations, starting from pre-industrial (PI) until stabilization at 4×PI CO2 concentrations (4×CO2). By comparing the one- and two-way coupled simulations, we find significant changes in atmospheric blocking, precipitation and cloud formation over Greenland as the GrIS topography evolves, acting as negative feedbacks on mass loss. We also attribute part of the overestimation of mass loss in the one-way coupled simulation to an overestimation of melt in the ablation area caused by the use of a uniform temperature lapse rate to reflect the elevation differences between the atmospheric and ice sheet grids. Furthermore, we investigate ice sheet–climate interactions in a simulation branched in year 350 from our two-way coupled simulation in which we annually reduce atmospheric CO2 by 5 % until PI concentrations are reached. During the 350-year 4×CO2 forcing period, the ice sheet loses a total mass of 1.1 m sea level equivalent, and part of its margins retreat landward. When the PI CO2 concentration is restored, melt decreases rapidly, leading to a small positive surface mass balance. Combined with the strongly reduced ice discharge resulting from the widespread retreat of the ice sheet margin, this halts GrIS mass loss despite a remaining global warming of 2 K. The GrIS, Arctic and North Atlantic strongly interact, causing a complex transitional phase towards a colder climate during the century following the CO2 reduction. Elevated atmospheric temperatures, larger ocean heat transport and deteriorated state of the snowpack, compared to the initial pre-industrial state, result in limited regrowth of the ice sheet under reintroduced PI CO2 conditions.
...
The Greenland ice sheet (GrIS) stores freshwater equal to more than 7 m of potential sea level rise (SLR) and strongly interacts with the Arctic, North Atlantic and global climate. Over the last few decades, the ice sheet has been losing mass at a rate that is projected to increase. Interactions between the GrIS and the climate have the potential to amplify or reduce GrIS mass balance responses to ongoing and projected warming. Here, we investigate the impact of ice sheet–climate interactions on the climate and mass balance of the GrIS using the Community Ice Sheet Model version 2 (CISM2) coupled with the Community Earth System Model version 2 (CESM2). To this end, we compare two idealized multi-century simulations with a non-evolving and evolving ice sheet topography in which we apply an annual 1 % increase in CO2 concentrations, starting from pre-industrial (PI) until stabilization at 4×PI CO2 concentrations (4×CO2). By comparing the one- and two-way coupled simulations, we find significant changes in atmospheric blocking, precipitation and cloud formation over Greenland as the GrIS topography evolves, acting as negative feedbacks on mass loss. We also attribute part of the overestimation of mass loss in the one-way coupled simulation to an overestimation of melt in the ablation area caused by the use of a uniform temperature lapse rate to reflect the elevation differences between the atmospheric and ice sheet grids. Furthermore, we investigate ice sheet–climate interactions in a simulation branched in year 350 from our two-way coupled simulation in which we annually reduce atmospheric CO2 by 5 % until PI concentrations are reached. During the 350-year 4×CO2 forcing period, the ice sheet loses a total mass of 1.1 m sea level equivalent, and part of its margins retreat landward. When the PI CO2 concentration is restored, melt decreases rapidly, leading to a small positive surface mass balance. Combined with the strongly reduced ice discharge resulting from the widespread retreat of the ice sheet margin, this halts GrIS mass loss despite a remaining global warming of 2 K. The GrIS, Arctic and North Atlantic strongly interact, causing a complex transitional phase towards a colder climate during the century following the CO2 reduction. Elevated atmospheric temperatures, larger ocean heat transport and deteriorated state of the snowpack, compared to the initial pre-industrial state, result in limited regrowth of the ice sheet under reintroduced PI CO2 conditions.
Journal article
(2025)
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Michele Petrini, Meike D.W. Scherrenberg, Laura Muntjewerf, Miren Vizcaino, Raymond Sellevold, Gunter R. Leguy, William H. Lipscomb, Heiko Goelzer
A major impact of anthropogenic climate change is the crossing of tipping points, which may have severe consequences such as the complete mass loss of the Greenland ice sheet (GrIS). At present, the GrIS is losing mass at an accelerated rate, largely due to a steep decrease in its surface mass balance (SMB; the balance between snow accumulation and surface ablation from melt and associated runoff). Previous work on the magnitude and nature of a threshold for GrIS complete melt remains controversial. Here, we explore a potential SMB threshold for complete melt of the GrIS; the impact and interplay of surface melt and glacial isostatic adjustment (GIA) in determining this threshold; and whether the GrIS exhibits characteristics commonly associated with tipping points, such as sensitivity to external forcing. To this end, we force the Community Ice Sheet Model v.2 (CISM2) by cycling different SMB climatologies previously calculated at multiple elevation classes with the Community Earth System Model v.2 (CESM2) in a two-way coupled CESM2-CISM2 transient simulation of the global climate and GrIS under high CO2 forcing. The SMB calculation in CESM2 has been evaluated with contemporary observations and high-resolution modelling and includes an advanced representation of surface melt and snow-firn processes. We find a positive SMB threshold for complete GrIS melt of 230 ± 84 Gtyr-1, corresponding to a 60 % decrease in SMB and to a global mean warming of +3.4 K compared to pre-industrial CESM2-CISM2 simulated values. In our simulations, a small change in the initial SMB forcing (from 255 to 230 Gtyr-1) and global mean warming above pre-industrial levels (from +3.2 to +3.4 K) causes an abrupt change in the GrIS final volume (from 50 % mass to nearly complete deglaciation). This nonlinear behaviour is caused by the SMB-elevation feedback, which responds to changes in surface topography due to surface melt and GIA. The GrIS tips from ∼ 50 % mass towards nearly complete melt when the impact of melt-induced surface lowering outweighs that of GIA-induced bedrock uplift and the (initially positive) SMB becomes and remains negative for at least a few thousand years. We also find that the GrIS tips towards nearly complete melt when the ice margin in the central west unpins from a coastal region with high topography and SMB. We show that if we keep the SMB fixed (i.e. no SMB-elevation feedback) in this relatively confined region, the ice sheet retreat is halted and nearly complete GrIS melt is prevented even though the initial SMB forcing is past the threshold. Based on the minimum GrIS configuration in previous paleo-ice-sheet modelling studies, we suggest that the surface topography in the central west might have played a role in preventing larger GrIS loss during the last interglacial period ∼ 130-115 kyrBP.
...
A major impact of anthropogenic climate change is the crossing of tipping points, which may have severe consequences such as the complete mass loss of the Greenland ice sheet (GrIS). At present, the GrIS is losing mass at an accelerated rate, largely due to a steep decrease in its surface mass balance (SMB; the balance between snow accumulation and surface ablation from melt and associated runoff). Previous work on the magnitude and nature of a threshold for GrIS complete melt remains controversial. Here, we explore a potential SMB threshold for complete melt of the GrIS; the impact and interplay of surface melt and glacial isostatic adjustment (GIA) in determining this threshold; and whether the GrIS exhibits characteristics commonly associated with tipping points, such as sensitivity to external forcing. To this end, we force the Community Ice Sheet Model v.2 (CISM2) by cycling different SMB climatologies previously calculated at multiple elevation classes with the Community Earth System Model v.2 (CESM2) in a two-way coupled CESM2-CISM2 transient simulation of the global climate and GrIS under high CO2 forcing. The SMB calculation in CESM2 has been evaluated with contemporary observations and high-resolution modelling and includes an advanced representation of surface melt and snow-firn processes. We find a positive SMB threshold for complete GrIS melt of 230 ± 84 Gtyr-1, corresponding to a 60 % decrease in SMB and to a global mean warming of +3.4 K compared to pre-industrial CESM2-CISM2 simulated values. In our simulations, a small change in the initial SMB forcing (from 255 to 230 Gtyr-1) and global mean warming above pre-industrial levels (from +3.2 to +3.4 K) causes an abrupt change in the GrIS final volume (from 50 % mass to nearly complete deglaciation). This nonlinear behaviour is caused by the SMB-elevation feedback, which responds to changes in surface topography due to surface melt and GIA. The GrIS tips from ∼ 50 % mass towards nearly complete melt when the impact of melt-induced surface lowering outweighs that of GIA-induced bedrock uplift and the (initially positive) SMB becomes and remains negative for at least a few thousand years. We also find that the GrIS tips towards nearly complete melt when the ice margin in the central west unpins from a coastal region with high topography and SMB. We show that if we keep the SMB fixed (i.e. no SMB-elevation feedback) in this relatively confined region, the ice sheet retreat is halted and nearly complete GrIS melt is prevented even though the initial SMB forcing is past the threshold. Based on the minimum GrIS configuration in previous paleo-ice-sheet modelling studies, we suggest that the surface topography in the central west might have played a role in preventing larger GrIS loss during the last interglacial period ∼ 130-115 kyrBP.
Surface mass balance and climate of the Last Glacial Maximum Northern Hemisphere ice sheets
Simulations with CESM2.1
Journal article
(2024)
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Sarah L. Bradley, Raymond Sellevold, Michele Petrini, Miren Vizcaino, Sotiria Georgiou, Jiang Zhu, Bette L. Otto-Bliesner, Marcus Lofverstrom
The Last Glacial Maximum (LGM, from ∼26 to 20 ka BP) was the most recent period with large ice sheets in Eurasia and North America. At that time, global temperatures were 5–7 ∘C lower than today, and sea level ∼125 m lower. LGM simulations are useful to understand earth system dynamics, including climate–ice sheet interactions, and to evaluate and improve the models representing those dynamics. Here, we present two simulations of the Northern Hemisphere ice sheet climate and surface mass balance (SMB) with the Community Earth System Model v2.1 (CESM2.1) using the Community Atmosphere Model v5 (CAM5) with prescribed ice sheets for two time periods that bracket the LGM period: 26 and 21 ka BP. CESM2.1 includes an explicit simulation of snow/firn compaction, albedo, refreezing, and direct coupling of the ice sheet surface energy fluxes with the atmosphere. The simulated mean snow accumulation is lowest for the Greenland and Barents–Kara Sea ice sheets (GrIS, BKIS) and highest for British and Irish (BIIS) and Icelandic (IcIS) ice sheets. Melt rates are negligible for the dry BKIS and GrIS, and relatively large for the BIIS, North American ice sheet complex (NAISC; i.e. Laurentide, Cordilleran, and Innuitian), Scandinavian ice sheet (SIS), and IcIS, and are reduced by almost a third in the colder (lower temperature) 26 ka BP climate compared with 21 ka BP. The SMB is positive for the GrIS, BKIS, SIS, and IcIS during the LGM (26 and 21 ka BP) and negative for the NAISC and BIIS. Relatively wide ablation areas are simulated along the southern (terrestrial), Pacific and Atlantic margins of the NAISC, across the majority of the BIIS, and along the terrestrial southern margin of the SIS. The integrated SMB substantially increases for the NAISC and BIIS in the 26 ka BP climate, but it does not reverse the negative sign. Summer incoming surface solar radiation is largest over the high interior of the NAISC and GrIS, and minimum over the BIIS and southern margin of NAISC. Summer net radiation is maximum over the ablation areas and minimum where the albedo is highest, namely in the interior of the GrIS, northern NAISC, and all of the BKIS. Summer sensible and latent heat fluxes are highest over the ablation areas, positively contributing to melt energy. Refreezing is largest along the equilibrium line altitude for all ice sheets and prevents 40 %–50 % of meltwater entering the ocean. The large simulated melt for the NAISC suggests potential biases in the climate simulation, ice sheet reconstruction, and/or highly non-equilibrated climate and ice sheet at the LGM time.
...
The Last Glacial Maximum (LGM, from ∼26 to 20 ka BP) was the most recent period with large ice sheets in Eurasia and North America. At that time, global temperatures were 5–7 ∘C lower than today, and sea level ∼125 m lower. LGM simulations are useful to understand earth system dynamics, including climate–ice sheet interactions, and to evaluate and improve the models representing those dynamics. Here, we present two simulations of the Northern Hemisphere ice sheet climate and surface mass balance (SMB) with the Community Earth System Model v2.1 (CESM2.1) using the Community Atmosphere Model v5 (CAM5) with prescribed ice sheets for two time periods that bracket the LGM period: 26 and 21 ka BP. CESM2.1 includes an explicit simulation of snow/firn compaction, albedo, refreezing, and direct coupling of the ice sheet surface energy fluxes with the atmosphere. The simulated mean snow accumulation is lowest for the Greenland and Barents–Kara Sea ice sheets (GrIS, BKIS) and highest for British and Irish (BIIS) and Icelandic (IcIS) ice sheets. Melt rates are negligible for the dry BKIS and GrIS, and relatively large for the BIIS, North American ice sheet complex (NAISC; i.e. Laurentide, Cordilleran, and Innuitian), Scandinavian ice sheet (SIS), and IcIS, and are reduced by almost a third in the colder (lower temperature) 26 ka BP climate compared with 21 ka BP. The SMB is positive for the GrIS, BKIS, SIS, and IcIS during the LGM (26 and 21 ka BP) and negative for the NAISC and BIIS. Relatively wide ablation areas are simulated along the southern (terrestrial), Pacific and Atlantic margins of the NAISC, across the majority of the BIIS, and along the terrestrial southern margin of the SIS. The integrated SMB substantially increases for the NAISC and BIIS in the 26 ka BP climate, but it does not reverse the negative sign. Summer incoming surface solar radiation is largest over the high interior of the NAISC and GrIS, and minimum over the BIIS and southern margin of NAISC. Summer net radiation is maximum over the ablation areas and minimum where the albedo is highest, namely in the interior of the GrIS, northern NAISC, and all of the BKIS. Summer sensible and latent heat fluxes are highest over the ablation areas, positively contributing to melt energy. Refreezing is largest along the equilibrium line altitude for all ice sheets and prevents 40 %–50 % of meltwater entering the ocean. The large simulated melt for the NAISC suggests potential biases in the climate simulation, ice sheet reconstruction, and/or highly non-equilibrated climate and ice sheet at the LGM time.
Journal article
(2020)
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Laura Muntjewerf, Michele Petrini, Miren Vizcaino, Carolina Ernani da Silva, Raymond Sellevold, Meike D.W. Scherrenberg, Katherine Thayer-Calder, Sarah L. Bradley, Jan T.M. Lenaerts, More authors...
The Greenland Ice Sheet (GrIS) mass balance is examined with an Earth system/ice sheet model that interactively couples the GrIS to the broader Earth system. The simulation runs from 1850 to 2100, with historical and SSP5-8.5 forcing. By the mid-21st century, the cumulative GrIS contribution to global mean sea level rise (SLR) is 23 mm. During the second half of the 21st century, the surface mass balance becomes negative in all drainage basins, with an additional SLR contribution of 86 mm. The annual mean GrIS mass loss in the last two decades is 2.7-mm sea level equivalent (SLE) year−1. The increased SLR contribution from the surface mass balance (3.1 mm SLE year−1) is partly offset by reduced ice discharge from thinning and retreat of outlet glaciers. The southern GrIS drainage basins contribute 73% of the mass loss in mid-century but 55% by 2100, as surface runoff increases in the northern basins.
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The Greenland Ice Sheet (GrIS) mass balance is examined with an Earth system/ice sheet model that interactively couples the GrIS to the broader Earth system. The simulation runs from 1850 to 2100, with historical and SSP5-8.5 forcing. By the mid-21st century, the cumulative GrIS contribution to global mean sea level rise (SLR) is 23 mm. During the second half of the 21st century, the surface mass balance becomes negative in all drainage basins, with an additional SLR contribution of 86 mm. The annual mean GrIS mass loss in the last two decades is 2.7-mm sea level equivalent (SLE) year−1. The increased SLR contribution from the surface mass balance (3.1 mm SLE year−1) is partly offset by reduced ice discharge from thinning and retreat of outlet glaciers. The southern GrIS drainage basins contribute 73% of the mass loss in mid-century but 55% by 2100, as surface runoff increases in the northern basins.
Journal article
(2020)
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R. Falk, V. Pálinkáš, H. Wziontek, S. Castelein, J. D. Bernard, A. Rülke, F. Greco, R. Reudink, M. Petrini, More Authors...
The regional key comparison of absolute gravimeters, EURAMET.M.G-K3 and the simultaneously organized additional comparison, was held in Germany at the Geodetic Observatory Wettzell of the German Federal Agency for Cartography and Geodesy in the spring of 2018.
Here we present the list of the participants who actually performed measurements during the comparison, the data submitted by the operators as well as the results of the determination of the gravity as a function of height at the comparison sites. The measurement strategy is briefly discussed and the results of the data harmonization is documented. Finally, the results of the constrained least squares adjustment are presented including the degrees of equivalence of each gravimeter and the key comparison reference values. ...
Here we present the list of the participants who actually performed measurements during the comparison, the data submitted by the operators as well as the results of the determination of the gravity as a function of height at the comparison sites. The measurement strategy is briefly discussed and the results of the data harmonization is documented. Finally, the results of the constrained least squares adjustment are presented including the degrees of equivalence of each gravimeter and the key comparison reference values. ...
The regional key comparison of absolute gravimeters, EURAMET.M.G-K3 and the simultaneously organized additional comparison, was held in Germany at the Geodetic Observatory Wettzell of the German Federal Agency for Cartography and Geodesy in the spring of 2018.
Here we present the list of the participants who actually performed measurements during the comparison, the data submitted by the operators as well as the results of the determination of the gravity as a function of height at the comparison sites. The measurement strategy is briefly discussed and the results of the data harmonization is documented. Finally, the results of the constrained least squares adjustment are presented including the degrees of equivalence of each gravimeter and the key comparison reference values.
Here we present the list of the participants who actually performed measurements during the comparison, the data submitted by the operators as well as the results of the determination of the gravity as a function of height at the comparison sites. The measurement strategy is briefly discussed and the results of the data harmonization is documented. Finally, the results of the constrained least squares adjustment are presented including the degrees of equivalence of each gravimeter and the key comparison reference values.
Journal article
(2020)
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Laura Muntjewerf, Raymond Sellevold, William H. Lipscomb, Marcus Lofverstrom, William J. Sacks, Miren Vizcaino, Carolina Ernani da Silva, Michele Petrini, Katherine Thayer-Calder, Meike D.W. Scherrenberg, Sarah L. Bradley, Caroline Katsman, Jeremy Fyke
The Greenland ice sheet (GrIS) is now losing mass at a rate of 0.7 mm of sea level rise (SLR) per year. Here we explore future GrIS evolution and interactions with global and regional climate under high greenhouse gas forcing with the Community Earth System Model version 2.1 (CESM2.1), which includes an interactive ice sheet component (the Community Ice Sheet Model v2.1 [CISM2.1]) and an advanced energy balance-based calculation of surface melt. We run an idealized 350-year scenario in which atmospheric CO2 concentration increases by 1% annually until reaching four times pre-industrial values at year 140, after which it is held fixed. The global mean temperature increases by 5.2 and 8.5 K by years 131–150 and 331–350, respectively. The projected GrIS contribution to global mean SLR is 107 mm by year 150 and 1,140 mm by year 350. The rate of SLR increases from 2 mm yr−1 at year 150 to almost 7 mm yr−1 by year 350. The accelerated mass loss is caused by rapidly increasing surface melt as the ablation area expands, with associated albedo feedback and increased sensible and latent heat fluxes. This acceleration occurs for a global warming of approximately 4.2 K with respect to pre-industrial and is in part explained by the quasi-parabolic shape of the ice sheet, which favors rapid expansion of the ablation area as it approaches the interior “plateau.”.
...
The Greenland ice sheet (GrIS) is now losing mass at a rate of 0.7 mm of sea level rise (SLR) per year. Here we explore future GrIS evolution and interactions with global and regional climate under high greenhouse gas forcing with the Community Earth System Model version 2.1 (CESM2.1), which includes an interactive ice sheet component (the Community Ice Sheet Model v2.1 [CISM2.1]) and an advanced energy balance-based calculation of surface melt. We run an idealized 350-year scenario in which atmospheric CO2 concentration increases by 1% annually until reaching four times pre-industrial values at year 140, after which it is held fixed. The global mean temperature increases by 5.2 and 8.5 K by years 131–150 and 331–350, respectively. The projected GrIS contribution to global mean SLR is 107 mm by year 150 and 1,140 mm by year 350. The rate of SLR increases from 2 mm yr−1 at year 150 to almost 7 mm yr−1 by year 350. The accelerated mass loss is caused by rapidly increasing surface melt as the ablation area expands, with associated albedo feedback and increased sensible and latent heat fluxes. This acceleration occurs for a global warming of approximately 4.2 K with respect to pre-industrial and is in part explained by the quasi-parabolic shape of the ice sheet, which favors rapid expansion of the ablation area as it approaches the interior “plateau.”.
Journal article
(2020)
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Michele Petrini, Florence Colleoni, Jan Mangerud, Nina Kirchner, Anna L.C. Hughes, Angelo Camerlenghi, Michele Rebesco, Renata G. Lucchi, Emanuele Forte, Renato R. Colucci, Riko Noormets
The Barents Sea Ice Sheet was part of an interconnected complex of ice sheets, collectively referred to as the Eurasian Ice Sheet, which covered north-westernmost Europe, Russia and the Barents Sea during the Last Glacial Maximum (around 21 ky BP). Due to common geological features, the Barents Sea component of this ice complex is seen as a paleo-analogue for the present-day West Antarctic Ice Sheet. Investigating key processes driving the last deglaciation of the Barents Sea Ice Sheet represents an important tool to interpret recent observations in Antarctica over the multi-millennial temporal scale of glaciological changes. We present results from a perturbed physics ensemble of ice sheet model simulations of the last deglaciation of the Barents Sea Ice Sheet, forced with transient atmospheric and oceanic conditions derived from AOGCM simulations. The ensemble of transient simulations is evaluated against the data-based DATED-1 reconstruction to construct minimum, maximum and average deglaciation scenarios. Despite a large model/data mismatch at the western and eastern ice sheet margins, the simulated and DATED-1 deglaciation scenarios agree well on the timing of the deglaciation of the central and northern Barents Sea. We find that the simulated deglaciation of the Barents Sea Ice Sheet is primarily driven by the oceanic forcing, with prescribed eustatic sea level rise amplifying the ice sheet sensitivity to sub-shelf melting over relatively short intervals. Our results highlight that the sub-shelf melting has a very strong control on the simulated grounding-line flux, showing that a slow, gradual ocean warming trend is capable of triggering sustained grounded ice discharge over multi-millennial timescales, even without taking into account marine ice sheet or ice cliff instability.
...
The Barents Sea Ice Sheet was part of an interconnected complex of ice sheets, collectively referred to as the Eurasian Ice Sheet, which covered north-westernmost Europe, Russia and the Barents Sea during the Last Glacial Maximum (around 21 ky BP). Due to common geological features, the Barents Sea component of this ice complex is seen as a paleo-analogue for the present-day West Antarctic Ice Sheet. Investigating key processes driving the last deglaciation of the Barents Sea Ice Sheet represents an important tool to interpret recent observations in Antarctica over the multi-millennial temporal scale of glaciological changes. We present results from a perturbed physics ensemble of ice sheet model simulations of the last deglaciation of the Barents Sea Ice Sheet, forced with transient atmospheric and oceanic conditions derived from AOGCM simulations. The ensemble of transient simulations is evaluated against the data-based DATED-1 reconstruction to construct minimum, maximum and average deglaciation scenarios. Despite a large model/data mismatch at the western and eastern ice sheet margins, the simulated and DATED-1 deglaciation scenarios agree well on the timing of the deglaciation of the central and northern Barents Sea. We find that the simulated deglaciation of the Barents Sea Ice Sheet is primarily driven by the oceanic forcing, with prescribed eustatic sea level rise amplifying the ice sheet sensitivity to sub-shelf melting over relatively short intervals. Our results highlight that the sub-shelf melting has a very strong control on the simulated grounding-line flux, showing that a slow, gradual ocean warming trend is capable of triggering sustained grounded ice discharge over multi-millennial timescales, even without taking into account marine ice sheet or ice cliff instability.
Poster
(2019)
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Laura Muntjewerf, William Lipscomb, Kate Thayer-Calder, Sarah Bradley, Jeremy Fyke, Carolina Ernani da Silva, Raymond Sellevold, Michele Petrini, Miren Vizcaino, More authors...
Journal article
(2018)
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Michele Petrini, Florence Colleoni, Nina Kirchner, Anna L.C. Hughes, Angelo Camerlenghi, Michele Rebesco, Renata G. Lucchi, Emanuele Forte, Renato R. Colucci, Riko Noormets
The Barents Sea Ice Sheet was a marine-based ice sheet, i.e., it rested on the Barents Sea floor during the Last Glacial Maximum (21 ky BP). The Bjørnøyrenna Ice Stream was the largest ice stream draining the Barents Sea Ice Sheet and is regarded as an analogue for contemporary ice streams in West Antarctica. Here, the retreat of the Bjørnøyrenna Ice Stream is simulated by means of two numerical ice sheet models and results assessed against geological data. We investigate the sensitivity of the ice stream to changes in ocean temperature and the impact of grounding-line physics on ice stream retreat. Our results suggest that the role played by sub-shelf melting depends on how the grounding-line physics is represented in the models. When an analytic constraint on the ice flux across the grounding line is applied, the retreat of Bjørnøyrenna Ice Stream is primarily driven by internal ice dynamics rather than by oceanic forcing. This suggests that implementations of grounding-line physics need to be carefully assessed when evaluating and predicting the response of contemporary marine-based ice sheets and individual ice streams to ongoing and future ocean warming.
...
The Barents Sea Ice Sheet was a marine-based ice sheet, i.e., it rested on the Barents Sea floor during the Last Glacial Maximum (21 ky BP). The Bjørnøyrenna Ice Stream was the largest ice stream draining the Barents Sea Ice Sheet and is regarded as an analogue for contemporary ice streams in West Antarctica. Here, the retreat of the Bjørnøyrenna Ice Stream is simulated by means of two numerical ice sheet models and results assessed against geological data. We investigate the sensitivity of the ice stream to changes in ocean temperature and the impact of grounding-line physics on ice stream retreat. Our results suggest that the role played by sub-shelf melting depends on how the grounding-line physics is represented in the models. When an analytic constraint on the ice flux across the grounding line is applied, the retreat of Bjørnøyrenna Ice Stream is primarily driven by internal ice dynamics rather than by oceanic forcing. This suggests that implementations of grounding-line physics need to be carefully assessed when evaluating and predicting the response of contemporary marine-based ice sheets and individual ice streams to ongoing and future ocean warming.
Erratum to
Interplay of grounding-line dynamics and sub-shelf melting during retreat of the Bjørnøyrenna Ice Stream (Scientific Reports, (2018), 8, 1, (7196), 10.1038/s41598-018-25664-6)
Journal article
(2018)
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Michele Petrini, Florence Colleoni, Nina Kirchner, Anna L.C. Hughes, Angelo Camerlenghi, Michele Rebesco, Renata G. Lucchi, Emanuele Forte, Renato R. Colucci, Riko Noormets
A correction to this article has been published and is linked from the HTML and PDF versions of this paper. The error has not been fixed in the paper.
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A correction to this article has been published and is linked from the HTML and PDF versions of this paper. The error has not been fixed in the paper.
Abstract
(2018)
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Miren Vizcaino, Laura Muntjewerf, Sarah Bradley, Michele Petrini, Jeremy Fyke, William Lipscomb, Leo van Kampenhout, Jan T M Lenaerts, Michiel R. van den Broeke, Raymond Sellevold, William Sacks
Ice sheets are a major component of the Earth System, however they are not yet interactively coupled to most global climate models. Here we present past achievements in this front with the CESM1.0 version as well as first results and challenges with the upcoming CESM2.0, where the Community Ice Sheet Model 2.1 is bi-directionally coupled to the atmospheric and ocean components, as opposed to only one-way coupling in CESM1.0. In both CESM versions, the surface mass balance (SMB) is calculated in the land component (CLM) with explicit albedo and refreezing calculations, and downscaled to the ice sheet model resolution via elevation classes and bi-linear (horizontal) and linear (vertical) interpolations. A major highlight of CESM is that the most important coupling process between ice sheet and atmosphere, the albedo feedback, is explicitly modeled, as opposed to state-of-the-art parameterizations of albedo and/or surface melt. Regarding future Greenland ice sheet projections with CESM1, we summarize our results on: 1) doubled end-of-the-century melt rates under RCP8.5 from increased incoming thermal radiation and turbulent fluxes despite decreased incoming solar radiation over Greenland from more clouds, 2) increase in SMB variability due to reduced accumulation to ablation area ration, 3) bimodal emergence of an anthropogenic signal on the SMB due to both increasing melt and snow accumulation, 4) reduction in ice discharge from marginal thinning. We also outline work in progress in preparation for our contribution to the Ice Sheet Model Intercomparison Project 6 (ISMIP6) and paleo-research on the last deglaciation, e.g., on model initialization, improved SMB calculation, evaluation of CESM2.0 climate over Greenland, and parameter optimization of the higher-order CISM2.1.
...
Ice sheets are a major component of the Earth System, however they are not yet interactively coupled to most global climate models. Here we present past achievements in this front with the CESM1.0 version as well as first results and challenges with the upcoming CESM2.0, where the Community Ice Sheet Model 2.1 is bi-directionally coupled to the atmospheric and ocean components, as opposed to only one-way coupling in CESM1.0. In both CESM versions, the surface mass balance (SMB) is calculated in the land component (CLM) with explicit albedo and refreezing calculations, and downscaled to the ice sheet model resolution via elevation classes and bi-linear (horizontal) and linear (vertical) interpolations. A major highlight of CESM is that the most important coupling process between ice sheet and atmosphere, the albedo feedback, is explicitly modeled, as opposed to state-of-the-art parameterizations of albedo and/or surface melt. Regarding future Greenland ice sheet projections with CESM1, we summarize our results on: 1) doubled end-of-the-century melt rates under RCP8.5 from increased incoming thermal radiation and turbulent fluxes despite decreased incoming solar radiation over Greenland from more clouds, 2) increase in SMB variability due to reduced accumulation to ablation area ration, 3) bimodal emergence of an anthropogenic signal on the SMB due to both increasing melt and snow accumulation, 4) reduction in ice discharge from marginal thinning. We also outline work in progress in preparation for our contribution to the Ice Sheet Model Intercomparison Project 6 (ISMIP6) and paleo-research on the last deglaciation, e.g., on model initialization, improved SMB calculation, evaluation of CESM2.0 climate over Greenland, and parameter optimization of the higher-order CISM2.1.