scholarly journals Mechanisms and time scales of glacial inception simulated with an Earth system model of intermediate complexity

2009 ◽  
Vol 5 (2) ◽  
pp. 245-258 ◽  
Author(s):  
R. Calov ◽  
A. Ganopolski ◽  
C. Kubatzki ◽  
M. Claussen
Keyword(s):  
Transient Response ◽  
Ice Sheet ◽  
Earth System Model ◽  
System Model ◽  
Earth System ◽  
Intermediate Complexity ◽  
Transient Simulations ◽  
Ice Sheet Dynamics ◽  
Inland Ice ◽  
Equilibrium Simulation

Abstract. We investigate glacial inception and glacial thresholds in the climate-cryosphere system utilising the Earth system model of intermediate complexity CLIMBER-2, which includes modules for atmosphere, terrestrial vegetation, ocean and interactive ice sheets. The latter are described by the three-dimensional polythermal ice-sheet model SICOPOLIS. A bifurcation which represents glacial inception is analysed with two different model setups: one setup with dynamical ice-sheet model and another setup without it. The respective glacial thresholds differ in terms of maximum boreal summer insolation at 65° N (hereafter referred as Milankovitch forcing (MF)). The glacial threshold of the configuration without ice-sheet dynamics corresponds to a much lower value of MF compared to the full model. If MF attains values only slightly below the aforementioned threshold there is fast transient response. Depending on the value of MF relative to the glacial threshold, the transient response time of inland-ice volume in the model configuration with ice-sheet dynamics ranges from 10 000 to 100 000 years. Due to these long response times, a glacial threshold obtained in an equilibrium simulation is not directly applicable to the transient response of the climate-cryosphere system to time-dependent orbital forcing. It is demonstrated that in transient simulations just crossing of the glacial threshold does not imply large-scale glaciation of the Northern Hemisphere. We found that in transient simulations MF has to drop well below the glacial threshold determined in an equilibrium simulation to initiate glacial inception. Finally, we show that the asynchronous coupling between climate and inland-ice components allows one sufficient realistic simulation of glacial inception and, at the same time, a considerable reduction of computational costs.

scholarly journals Mechanisms and time scales of glacial inception simulated with an Earth system model of intermediate complexity

2009 ◽  
Vol 5 (1) ◽  
pp. 595-633 ◽  
Author(s):  
R. Calov ◽  
A. Ganopolski ◽  
C. Kubatzki ◽  
M. Claussen
Keyword(s):  
Time Scales ◽  
Transient Response ◽  
Ice Sheet ◽  
Earth System Model ◽  
System Model ◽  
Boreal Summer ◽  
Earth System ◽  
Intermediate Complexity ◽  
Ice Sheet Dynamics ◽  
Inland Ice

Abstract. We investigate glacial inception and glacial thresholds in the climate-cryosphere system utilising the Earth system model of intermediate complexity CLIMBER-2, which includes modules for atmosphere, terrestrial vegetation, ocean and interactive ice sheets. The latter are described by the three-dimensional polythermal ice-sheet model SICOPOLIS. A bifurcation which represents glacial inception is analysed with two different model setups: one setup with dynamical ice-sheet model and another setup without it. The respective glacial thresholds differ in terms of maximum boreal summer insolation at 65° N (hereafter referred as Milankovich forcing (MF)). The glacial threshold of the configuration without ice-sheet dynamics corresponds to a much lower value of the MF compared to the full model. If MF attains values only slightly below the aforementioned threshold there is fast transient response. Depending on the value of MF relative to the glacial threshold, the transient response time of inland-ice volume in the model configuration with ice-sheet dynamics ranges from 10 000 to 100 000 years. We investigate implications of these time scales for past glacial inceptions and for the overdue Holocene glaciation hypothesis by Ruddiman (W. F. Ruddiman, Climatic Change 2003, Vol. 61, 261–293). We also have shown that the asynchronous coupling between climate and inland-ice components allows one sufficient realistic simulation of glacial inception and, at the same time, a considerable reduction of computational costs.

scholarly journals Description of the Earth system model of intermediate complexity LOVECLIM version 1.2

2010 ◽  
Vol 3 (2) ◽  
pp. 603-633 ◽  
Author(s):  
H. Goosse ◽  
V. Brovkin ◽  
T. Fichefet ◽  
R. Haarsma ◽  
P. Huybrechts ◽  
...  
Keyword(s):  
Carbon Cycle ◽  
Sea Ice ◽  
Three Dimensional ◽  
Ice Sheets ◽  
Ice Sheet ◽  
Earth System Model ◽  
System Model ◽  
Earth System ◽  
Intermediate Complexity ◽  
Low Latitudes

Abstract. The main characteristics of the new version 1.2 of the three-dimensional Earth system model of intermediate complexity LOVECLIM are briefly described. LOVECLIM 1.2 includes representations of the atmosphere, the ocean and sea ice, the land surface (including vegetation), the ice sheets, the icebergs and the carbon cycle. The atmospheric component is ECBilt2, a T21, 3-level quasi-geostrophic model. The ocean component is CLIO3, which consists of an ocean general circulation model coupled to a comprehensive thermodynamic-dynamic sea-ice model. Its horizontal resolution is of 3° by 3°, and there are 20 levels in the ocean. ECBilt-CLIO is coupled to VECODE, a vegetation model that simulates the dynamics of two main terrestrial plant functional types, trees and grasses, as well as desert. VECODE also simulates the evolution of the carbon cycle over land while the ocean carbon cycle is represented by LOCH, a comprehensive model that takes into account both the solubility and biological pumps. The ice sheet component AGISM is made up of a three-dimensional thermomechanical model of the ice sheet flow, a visco-elastic bedrock model and a model of the mass balance at the ice-atmosphere and ice-ocean interfaces. For both the Greenland and Antarctic ice sheets, calculations are made on a 10 km by 10 km resolution grid with 31 sigma levels. LOVECLIM1.2 reproduces well the major characteristics of the observed climate both for present-day conditions and for key past periods such as the last millennium, the mid-Holocene and the Last Glacial Maximum. However, despite some improvements compared to earlier versions, some biases are still present in the model. The most serious ones are mainly located at low latitudes with an overestimation of the temperature there, a too symmetric distribution of precipitation between the two hemispheres, and an overestimation of precipitation and vegetation cover in the subtropics. In addition, the atmospheric circulation is too weak. The model also tends to underestimate the surface temperature changes (mainly at low latitudes) and to overestimate the ocean heat uptake observed over the last decades.

scholarly journals LCice 1.0 – a generalized Ice Sheet System Model coupler for LOVECLIM version 1.3: description, sensitivities, and validation with the Glacial Systems Model (GSM version D2017.aug17)

2018 ◽  
Vol 11 (9) ◽  
pp. 3883-3902 ◽  
Author(s):  
Taimaz Bahadory ◽  
Lev Tarasov
Keyword(s):  
Ice Sheet ◽  
Sheet Thickness ◽  
Coupled Model ◽  
Earth System Model ◽  
Meridional Overturning Circulation ◽  
System Model ◽  
Coupling Scheme ◽  
Earth System ◽  
Intermediate Complexity ◽  
Systems Model

Abstract. We have coupled an Earth system model of intermediate complexity (LOVECLIM) to the Glacial Systems Model (GSM) using the LCice 1.0 coupler. The coupling scheme is flexible enough to enable asynchronous coupling between any glacial cycle ice sheet model and (with some code work) any Earth system model of intermediate complexity (EMIC). This coupling includes a number of interactions between ice sheets and climate that are often neglected: dynamic meltwater runoff routing, novel downscaling for precipitation that corrects orographic forcing to the higher resolution ice sheet grid (“advective precipitation”), dynamic vertical temperature gradient, and ocean temperatures for sub-shelf melt. The sensitivity of the coupled model with respect to the selected parameterizations and coupling schemes is investigated. Each new coupling feature is shown to have a significant impact on ice sheet evolution. An ensemble of runs is used to explore the behaviour of the coupled model over a set of 2000 parameter vectors using present-day (PD) initial and boundary conditions. The ensemble of coupled model runs is compared against PD reanalysis data for atmosphere (2 m temperature, precipitation, jet stream, and Rossby number of jet), ocean (sea ice and Atlantic Meridional Overturning Circulation – AMOC), and Northern Hemisphere ice sheet thickness and extent. The parameter vectors are then narrowed by rejecting model runs (1700 CE to present) with regional land ice volume changes beyond an acceptance range. The selected subset forms the basis for ongoing work to explore the spatial–temporal phase space of the last two glacial cycles.

scholarly journals Description of the Earth system model of intermediate complexity LOVECLIM version 1.2

2010 ◽  
Vol 3 (1) ◽  
pp. 309-390 ◽  
Author(s):  
H. Goosse ◽  
V. Brovkin ◽  
T. Fichefet ◽  
R. Haarsma ◽  
P. Huybrechts ◽  
...  
Keyword(s):  
Carbon Cycle ◽  
Sea Ice ◽  
Three Dimensional ◽  
Ice Sheets ◽  
Ice Sheet ◽  
Earth System Model ◽  
System Model ◽  
Earth System ◽  
Intermediate Complexity ◽  
Low Latitudes

Abstract. The main characteristics of the new version 1.2 of the three-dimensional Earth system model of intermediate complexity LOVECLIM are briefly described. LOVECLIM 1.2 includes representations of the atmosphere, the ocean and sea ice, the land surface (including vegetation), the ice sheets, the icebergs and the carbon cycle. The atmospheric component is ECBilt2, a T21, 3-level quasi-geostrophic model. The oceanic component is CLIO3, which is made up of an ocean general circulation model coupled to a comprehensive thermodynamic-dynamic sea-ice model. Its horizontal resolution is 3° by 3°, and there are 20 levels in the ocean. ECBilt-CLIO is coupled to VECODE, a vegetation model that simulates the dynamics of two main terrestrial plant functional types, trees and grasses, as well as desert. VECODE also simulates the evolution of the carbon cycle over land while the oceanic carbon cycle is represented in LOCH, a comprehensive model that takes into account both the solubility and biological pumps. The ice sheet component AGISM is made up of a three-dimensional thermomechanical model of the ice sheet flow, a visco-elastic bedrock model and a model of the mass balance at the ice-atmosphere and ice ocean interfaces. For both the Greenland and Antarctic ice sheets, calculations are made on a 10 km by 10 km resolution grid with 31 sigma levels. LOVECLIM 1.2 reproduces well the major characteristics of the observed climate both for present-day conditions and for key past periods such as the last millennium, the mid-Holocene and the Last Glacial Maximum. However, despite some improvements compared to earlier versions, some biases are still present in the model. The most serious ones are mainly located at low latitudes with an overestimation of the temperature there, a too symmetric distribution of precipitation between the two hemispheres, an overestimation of precipitation and vegetation cover in the subtropics. In addition, the atmospheric circulation is too weak. The model also tends to underestimate the surface temperature changes (mainly at low latitudes) and to overestimate the ocean heat uptake observed over the last decades.

scholarly journals Ice sheet dynamics within an Earth system model: coupling and first results on ice stability and ocean circulation

2013 ◽  
Vol 6 (1) ◽  
pp. 1-35 ◽  
Author(s):  
D. Barbi ◽  
G. Lohmann ◽  
K. Grosfeld ◽  
M. Thoma
Keyword(s):  
Ocean Circulation ◽  
Ice Sheets ◽  
Ice Sheet ◽  
Coupled Model ◽  
Earth System Model ◽  
System Model ◽  
Earth System ◽  
First Results ◽  
Ice Sheet Dynamics ◽  
Model Setup

Abstract. We present first results from a coupled model setup, consisting of a state-of-the-art ice sheet model (RIMBAY), and the community earth system model COSMOS. We show that special care has to be provided in order to ensure physical distributions of the forcings, as well as numeric stability of the involved models. We demonstrate that a statistical downscaling is crucial for ice sheet stability, especially for southern Greenland where surface temperature are close to the melting point. The simulated ice sheets are stable when forced with pre-industrial greenhouse gas parameters, with limits comparable with present day ice orography. A setup with high CO2 level is used to demonstrate the effects of dynamic ice sheets compared to the standard parameterisation; the resulting changes on ocean circulation will also be discussed.

scholarly journals Erratum to: The earth system model of intermediate complexity CLIMBER-3α. Part I: description and performance for present-day conditions

2009 ◽  
Vol 34 (1) ◽  
pp. 151-151
Author(s):  
Marisa Montoya ◽  
Alexa Griesel ◽  
Anders Levermann ◽  
Juliette Mignot ◽  
Matthias Hofmann ◽  
...  
Keyword(s):  
Earth System Model ◽  
System Model ◽  
Earth System ◽  
Intermediate Complexity ◽  
The Earth ◽  
And Performance

scholarly journals MPAS-Albany Land Ice (MALI): A variable resolution ice sheet model for Earth system modeling using Voronoi grids

2018 ◽  
Author(s):  
Matthew J. Hoffman ◽  
Mauro Perego ◽  
Stephen F. Price ◽  
William H. Lipscomb ◽  
Douglas Jacobsen ◽  
...  
Keyword(s):  
Ice Sheet ◽  
Earth System Model ◽  
Coupled Systems ◽  
System Model ◽  
Type Model ◽  
Earth System ◽  
Ice Dynamics ◽  
Variable Resolution ◽  
Horizontal Advection ◽  
First Order

Abstract. We introduce MPAS-Albany Land Ice (MALI), a new, variable resolution land ice model that uses unstructured Voronoi grids on a plane or sphere. MALI is built using the Model for Prediction Across Scales (MPAS) framework for developing variable resolution Earth System Model components and the Albany multi-physics code base for solution of coupled systems of partial-differential equations, which itself makes use of Trilinos solver libraries. MALI includes a three-dimensional, first-order momentum balance solver ("Blatter-Pattyn") by linking to the Albany-LI ice sheet velocity solver, as well as an explicit shallow ice velocity solver. Evolution of ice geometry and tracers is handled through an explicit first-order horizontal advection scheme with vertical remapping. Evolution of ice temperature is treated using operator splitting of vertical diffusion and horizontal advection and can be configured to use either a temperature or enthalpy formulation. MALI includes a mass-conserving subglacial hydrology model that supports distributed and/or channelized drainage and can optionally be coupled to ice dynamics. Options for calving include "eigencalving", which assumes calving rate is proportional to extensional strain rates. MALI is evaluated against commonly used exact solutions and community benchmark experiments and shows the expected accuracy. We report first results for the MISMIP3d benchmark experiments for a Blatter-Pattyn type model and show that results fall in-between those of models using Stokes flow and L1L2 approximations. We use the model to simulate a semi-realistic Antarctic Ice Sheet problem for 1100 years at 20 km resolution. MALI is the glacier component of the Energy Exascale Earth System Model (E3SM) version 1, and we describe current and planned coupling to other components.

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