scholarly journals Integrated summer insolation forcing and 40,000-year glacial cycles: The perspective from an ice-sheet/energy-balance model

2008 ◽  
Vol 23 (1) ◽  
pp. n/a-n/a ◽  
Author(s):  
Peter Huybers ◽  
Eli Tziperman
Keyword(s):  
Energy Balance ◽  
Ice Sheet ◽  
Energy Balance Model ◽  
Balance Model ◽  
Glacial Cycles ◽  
Summer Insolation ◽  
Insolation Forcing

scholarly journals Response of the Energy Balance on the Margin of the Greenland Ice Sheet to Temperature Changes

1990 ◽  
Vol 36 (123) ◽  
pp. 217-221 ◽  
Author(s):  
Roger J. Braithwaite ◽  
Ole B. Olesen
Keyword(s):  
Heat Flux ◽  
Energy Balance ◽  
Air Temperature ◽  
Sensible Heat Flux ◽  
Ice Sheet ◽  
Temperature Response ◽  
Greenland Ice Sheet ◽  
Energy Balance Model ◽  
Balance Model ◽  
Sensible Heat

AbstractDaily ice ablation on two outlet glaciers from the Greenland ice sheet, Nordbogletscher (1979–83) and Qamanârssûp sermia (1980–86), is related to air temperature by a linear regression equation. Analysis of this ablation-temperature equation with the help of a simple energy-balance model shows that sensible-heat flux has the greatest temperature response and accounts for about one-half of the temperature response of ablation. Net radiation accounts for about one-quarter of the temperature response of ablation, and latent-heat flux and errors account for the remainder. The temperature response of sensible-heat flux at QQamanârssûp sermia is greater than at Nordbogletscher mainly due to higher average wind speeds. The association of high winds with high temperatures during Föhn events further increases sensible-heat flux. The energy-balance model shows that ablation from a snow surface is only about half that from an ice surface at the same air temperature.

scholarly journals Response of the Energy Balance on the Margin of the Greenland Ice Sheet to Temperature Changes

1990 ◽  
Vol 36 (123) ◽  
pp. 217-221 ◽  
Author(s):  
Roger J. Braithwaite ◽  
Ole B. Olesen
Keyword(s):  
Heat Flux ◽  
Energy Balance ◽  
Air Temperature ◽  
Sensible Heat Flux ◽  
Ice Sheet ◽  
Temperature Response ◽  
Greenland Ice Sheet ◽  
Energy Balance Model ◽  
Balance Model ◽  
Sensible Heat

AbstractDaily ice ablation on two outlet glaciers from the Greenland ice sheet, Nordbogletscher (1979–83) and Qamanârssûp sermia (1980–86), is related to air temperature by a linear regression equation. Analysis of this ablation-temperature equation with the help of a simple energy-balance model shows that sensible-heat flux has the greatest temperature response and accounts for about one-half of the temperature response of ablation. Net radiation accounts for about one-quarter of the temperature response of ablation, and latent-heat flux and errors account for the remainder. The temperature response of sensible-heat flux at QQamanârssûp sermia is greater than at Nordbogletscher mainly due to higher average wind speeds. The association of high winds with high temperatures during Föhn events further increases sensible-heat flux. The energy-balance model shows that ablation from a snow surface is only about half that from an ice surface at the same air temperature.

scholarly journals The interaction between an ice sheet and its atmospheric boundary layer

1993 ◽  
Vol 39 (133) ◽  
pp. 601-608
Author(s):  
Alison Hall ◽  
Keith Weston
Keyword(s):  
Boundary Layer ◽  
Energy Balance ◽  
Atmospheric Boundary Layer ◽  
Reasonable Agreement ◽  
Ice Sheet ◽  
Global Scale ◽  
Energy Balance Model ◽  
Balance Model ◽  
Slab Model ◽  
Ablation Process

AbstractThe importance of the atmospheric boundary layer for the coupling between the climate and an ice sheet is investigated using a slab model of the atmospheric boundary layer. The model is shown to give reasonable agreement with observations over Antarctica and it is used to look at the effect of different ice-sheet shapes on the boundary layer. The importance of entrainment in bringing heat to the surface is highlighted and is shown to be particularly significant when the ice profile becomes steeper. The model could be used as part of an energy-balance model of snow in order to incorporate the interplay of the boundary layer and ice-sheet shape in the ablation process. The slab model could also be used in a GCM as a parameterization of these sub-grid scale processes which are at present ignored in models on a global scale.

scholarly journals Increased Ablation at the Margin of the Greenland Ice Sheet under a Greenhouse-Effect Climate

1990 ◽  
Vol 14 ◽  
pp. 20-22 ◽  
Author(s):  
Roger J. Braithwaite ◽  
Ole B. Olesen
Keyword(s):  
Energy Balance ◽  
Greenhouse Effect ◽  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
Ablation Rate ◽  
Summer Temperature ◽  
Energy Balance Model ◽  
Balance Model ◽  
Climatic Warming ◽  
West Greenland

Increased ablation under a greenhouse-effect climate is calculated by an energy-balance model for two sites at the margin of the Greenland ice sheet: Nordbogletscher, south Greenland, and Qamanârssûp sermia, West Greenland. The change in summer ablation is nearly linear with change in summer temperature, with gradients of 0.43 and 0.57 m water a−1 deg−1 for Nordbogletscher and Qamanârssûp sermia, respectively. However, the increase in ablation rate must be less in the higher parts of the ice sheet. A future climatic warming will therefore cause a rapid retreat of the ice-sheet margin and a steeper ice-sheet profile.

scholarly journals The interaction between an ice sheet and its atmospheric boundary layer

1993 ◽  
Vol 39 (133) ◽  
pp. 601-608
Author(s):  
Alison Hall ◽  
Keith Weston
Keyword(s):  
Boundary Layer ◽  
Energy Balance ◽  
Atmospheric Boundary Layer ◽  
Reasonable Agreement ◽  
Ice Sheet ◽  
Global Scale ◽  
Energy Balance Model ◽  
Balance Model ◽  
Slab Model ◽  
Ablation Process

AbstractThe importance of the atmospheric boundary layer for the coupling between the climate and an ice sheet is investigated using a slab model of the atmospheric boundary layer. The model is shown to give reasonable agreement with observations over Antarctica and it is used to look at the effect of different ice-sheet shapes on the boundary layer. The importance of entrainment in bringing heat to the surface is highlighted and is shown to be particularly significant when the ice profile becomes steeper. The model could be used as part of an energy-balance model of snow in order to incorporate the interplay of the boundary layer and ice-sheet shape in the ablation process. The slab model could also be used in a GCM as a parameterization of these sub-grid scale processes which are at present ignored in models on a global scale.

scholarly journals A Simple Energy-Balance Model to Calculate Ice Ablation at the Margin of the Greenland Ice Sheet

1990 ◽  
Vol 36 (123) ◽  
pp. 222-228 ◽  
Author(s):  
Roger J. Braithwaite ◽  
Ole Β. Olesen
Keyword(s):  
Energy Balance ◽  
Sensible Heat Flux ◽  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
Ablation Rate ◽  
Short Wave ◽  
Energy Balance Model ◽  
Balance Model ◽  
Wave Radiation ◽  
Climate Data

AbstractData for daily ice ablation on two outlets from the Greenland ice sheet, Nordbogletscher (1979–83) and Qamanârssûp sermia (1980–86), are used to test a simple energy-balance model which calculates ablation from climate data. The mean errors of the model are only −1.1 and −1.3 mm water d−1 for Nordbogletscher (14 months) and Qamanârssûp sermia (21 months), respectively, with standard deviations of ±13.6 and ±18.9 mm water d−1 for calculating daily ablation. The larger error for Qamanârssûp sermia may be due to variations in ice albedo but the model also underestimates ablation during Föhn events.According to the model, radiation accounts for about two-thirds of mean ablation for June-August at the two sites, while turbulent fluxes account for about one-third. The average ablation rate is higher at Qamanârssûp sermia than at Nordbogletscher because both sensible-heat flux and short-wave radiation are higher.

scholarly journals Increased Ablation at the Margin of the Greenland Ice Sheet under a Greenhouse-Effect Climate

1990 ◽  
Vol 14 ◽  
pp. 20-22 ◽  
Author(s):  
Roger J. Braithwaite ◽  
Ole B. Olesen
Keyword(s):  
Energy Balance ◽  
Greenhouse Effect ◽  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
Ablation Rate ◽  
Summer Temperature ◽  
Energy Balance Model ◽  
Balance Model ◽  
Climatic Warming ◽  
West Greenland

Increased ablation under a greenhouse-effect climate is calculated by an energy-balance model for two sites at the margin of the Greenland ice sheet: Nordbogletscher, south Greenland, and Qamanârssûp sermia, West Greenland. The change in summer ablation is nearly linear with change in summer temperature, with gradients of 0.43 and 0.57 m water a−1 deg−1 for Nordbogletscher and Qamanârssûp sermia, respectively. However, the increase in ablation rate must be less in the higher parts of the ice sheet. A future climatic warming will therefore cause a rapid retreat of the ice-sheet margin and a steeper ice-sheet profile.

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