A simplified permafrost-carbon model for long-term climate studies with the CLIMBER-2 coupled earth system model

Crichton, Katherine; Roche, Didier M.; Krinner, Gerhard; Chappellaz, J.

doi:10.5194/gmd-7-3111-2014

Cited by 10 publications

(6 citation statements)

References 56 publications

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“…Crichton et al . () estimate this loss of land area due to sea transgression since the LGM in the CLIMBER‐2 model to be about 5–7 × 10 6 km 2 .…”

Section: Resultsmentioning

confidence: 99%

“…This discrepancy is important to note because we model permafrost occurring on the East Siberian Arctic Shelf during the LGM but do not model its subsequent progression as subsea permafrost, some of which still currently exists today in the Laptev and East Siberian Seas (Romanovskii et al, 2004). Crichton et al (2014) estimate this loss of land area due to sea transgression since the LGM in the CLIMBER-2 model to be about 5-7 Â 10 6 km 2 .…”

Section: Permafrost Analysismentioning

confidence: 99%

See 1 more Smart Citation

Coupling of VAMPERS within iLOVECLIM: experiments during the LGM and Last Deglaciation

Kitover

Renssen

Balen

et al. 2019

J Quaternary Science

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The VAMPERS (Vrije Universiteit Amsterdam Permafrost Snow Model) has been coupled within iLOVECLIM, an earth system model. This advancement allows the thermal coupling between permafrost and climate to be examined from a millennial timescale using equilibrium experiments during the Last Glacial Maximum (21 ka) and transient experiments for the subsequent deglaciation period (21–11 ka). It appears that the role of permafrost during both stable and transitional (glacial–interglacial) climate periods is seasonal, resulting in cooler summers and warmer winters by approximately ±2 °C maximum. This conclusion reinforces the importance of including the active layer within climate models. In addition, the coupling of VAMPERS also yields a simulation of transient permafrost conditions, not only for estimating areal changes in extent but also total permafrost gain/loss.

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“…Crichton et al . () estimate this loss of land area due to sea transgression since the LGM in the CLIMBER‐2 model to be about 5–7 × 10 6 km 2 .…”

Section: Resultsmentioning

confidence: 99%

Section: Permafrost Analysismentioning

confidence: 99%

Coupling of VAMPERS within iLOVECLIM: experiments during the LGM and Last Deglaciation

Kitover

Renssen

Balen

et al. 2019

J Quaternary Science

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show abstract

“…Mainly due to the spatial heterogeneity of permafrost area and organic carbon content in permafrost soils (for example some peatland areas contain more than 100 kg m −2 , others far less than 30 kg m −2 ), this value bears large uncertainties (see e.g. Zimov et al, 2009;Crichton et al, 2014).…”

Section: Formulation Of Permafrostmentioning

confidence: 99%

An improved land biosphere module for use in the DCESS Earth system model (version 1.1) with application to the last glacial termination

et al. 2017

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Abstract. Interactions between the land biosphere and the atmosphere play an important role for the Earth's carbon cycle and thus should be considered in studies of global carbon cycling and climate. Simple approaches are a useful first step in this direction but may not be applicable for certain climatic conditions. To improve the ability of the reduced-complexity Danish Center for Earth System Science (DCESS) Earth system model DCESS to address cold climate conditions, we reformulated the model's land biosphere module by extending it to include three dynamically varying vegetation zones as well as a permafrost component. The vegetation zones are formulated by emulating the behaviour of a complex land biosphere model. We show that with the new module, the size and timing of carbon exchanges between atmosphere and land are represented more realistically in cooling and warming experiments. In particular, we use the new module to address carbon cycling and climate change across the last glacial transition. Within the constraints provided by various proxy data records, we tune the DCESS model to a Last Glacial Maximum state and then conduct transient sensitivity experiments across the transition under the application of explicit transition functions for high-latitude ocean exchange, atmospheric dust, and the land ice sheet extent. We compare simulated time evolutions of global mean temperature, pCO 2 , atmospheric and oceanic carbon isotopes as well as ocean dissolved oxygen concentrations with proxy data records. In this way we estimate the importance of different processes across the transition with emphasis on the role of land biosphere variations and show that carbon outgassing from permafrost and uptake of carbon by the land biosphere broadly compensate for each other during the temperature rise of the early last deglaciation.

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“…It is implemented at a much higher spatial resolution than the original CLIMBER-2 land surface scheme, and it is coupled to an ice sheet model. It can therefore be regarded as complementary to the CLIMBER-2 developments described in Crichton et al (2014).…”

Section: Introductionmentioning

confidence: 99%

“…Recently, a permafrost module has been included in CLIMBER-2 (Crichton et al, 2014). It was introduced for the purpose of an improved representation of the land carbon cycle.…”

Section: Introductionmentioning

confidence: 99%

Coupled Northern Hemisphere permafrost–ice-sheet evolution over the last glacial cycle

Willeit

Ganopolski

2015

Clim. Past

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Abstract. Permafrost influences a number of processes which are relevant for local and global climate. For example, it is well known that permafrost plays an important role in global carbon and methane cycles. Less is known about the interaction between permafrost and ice sheets. In this study a permafrost module is included in the Earth system model CLIMBER-2, and the coupled Northern Hemisphere (NH) permafrost-ice-sheet evolution over the last glacial cycle is explored.The model performs generally well at reproducing present-day permafrost extent and thickness. Modeled permafrost thickness is sensitive to the values of ground porosity, thermal conductivity and geothermal heat flux. Permafrost extent at the Last Glacial Maximum (LGM) agrees well with reconstructions and previous modeling estimates.Present-day permafrost thickness is far from equilibrium over deep permafrost regions. Over central Siberia and the Arctic Archipelago permafrost is presently up to 200-500 m thicker than it would be at equilibrium. In these areas, present-day permafrost depth strongly depends on the past climate history and simulations indicate that deep permafrost has a memory of surface temperature variations going back to at least 800 ka.Over the last glacial cycle permafrost has a relatively modest impact on simulated NH ice sheet volume except at LGM, when including permafrost increases ice volume by about 15 m sea level equivalent in our model. This is explained by a delayed melting of the ice base from below by the geothermal heat flux when the ice sheet sits on a porous sediment layer and permafrost has to be melted first. Permafrost affects ice sheet dynamics only when ice extends over areas covered by thick sediments, which is the case at LGM.

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A simplified permafrost-carbon model for long-term climate studies with the CLIMBER-2 coupled earth system model

Cited by 10 publications

References 56 publications

Coupling of VAMPERS within iLOVECLIM: experiments during the LGM and Last Deglaciation

Coupling of VAMPERS within iLOVECLIM: experiments during the LGM and Last Deglaciation

An improved land biosphere module for use in the DCESS Earth system model (version 1.1) with application to the last glacial termination

Coupled Northern Hemisphere permafrost–ice-sheet evolution over the last glacial cycle

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