Modelling submarine permafrost extent and development at the circum-Arctic scale
Abstract
Submarine permafrost is likely a key component of the permafrost-carbon climate feedback, but its current state and distribution on the Arctic shelves are largely unknown, aside from regions for which industry data are available. We present recent advances in modeling the dynamics of submarine permafrost on a range of spatial and temporal scales conducted within the EU H2020 Project "Nunataryuk -Permafrost thaw and the changing arctic coast: science for socio-economic adaptation".
We modelled the thermal regime of present-day submarine permafrost for the past 450 ka using distributed reconstructions of air temperature and ice sheet dynamics (from the CLIMBER 2 model), geothermal heat fluxes and sea level histories combined with modern bathymetry. The numerical model is a branch of the 1D heat flow CryoGrid 2 model, with repeated cycles of inundation driving surface temperatures at the upper boundary. The resulting map provides a first order estimate of submarine permafrost distribution and state that implies that much of the shelf can function as a cap on potential greenhouse gas stocks. We examine the evolution of permafrost in the Laptev, East Siberian, Beaufort and Barents seas, and in the Canadian Arctic Archipelago. The circum-Arctic dataset includes a map of the extent of cryotic sediment and the depth of cryotic sediment below the land or seabed. Relevant parameters such as ice saturation, which controls gas permeability and the thermal inertia of permafrost, and the enthalpy required to degrade permafrost completely, are also produced. Validation of the model includes comparison to existing sets of borehole and geophysical data. The applied method holds potential to investigate the following questions: How resilient is submarine permafrost to shelf water warming and freshening and shifting sediment dynamics? What are the implications for energy and mass fluxes from submarine permafrost under future changing conditions?- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2018
- Bibcode:
- 2018AGUFMOS11C1429W
- Keywords:
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- 3305 Climate change and variability;
- ATMOSPHERIC PROCESSESDE: 0702 Permafrost;
- CRYOSPHEREDE: 3004 Gas and hydrate systems;
- MARINE GEOLOGY AND GEOPHYSICS