Heat and salt flow in subsea permafrost modeled with CryoGRID2


Contact
michael.angelopoulos [ at ] awi.de

Abstract

Thawing of subsea permafrost can impact offshore infrastructure, affect coastal erosion, and release permafrost organic matter. Thawing is usually modeled as the result of heat transfer, although salt diffusion may play an important role in marine settings. To better quantify nearshore subsea permafrost thawing, we applied the CryoGRID2 heat diffusion model and coupled it to a salt diffusion model. We simulated coastline retreat and subsea permafrost evolution as it develops through successive stages of a thawing sequence at the Bykovsky Peninsula, Siberia. Sensitivity analyses for seawater salinity were performed to compare the results for the Bykovsky Peninsula with those of typical Arctic seawater. For the Bykovsky Peninsula, the modeled ice‐bearing permafrost table (IBPT) for ice‐rich sand and an erosion rate of 0.25 m/year was 16.7 m below the seabed 350 m offshore. The model outputs were compared to the IBPT depth estimated from coastline retreat and electrical resistivity surveys perpendicular to and crossing the shoreline of the Bykovsky Peninsula. The interpreted geoelectric data suggest that the IBPT dipped to 15–20 m below the seabed at 350 m offshore. Both results suggest that cold saline water forms beneath grounded ice and floating sea ice in shallow water, causing cryotic benthic temperatures. The freezing point depression produced by salt diffusion can delay or prevent ice formation in the sediment and enhance the IBPT degradation rate. Therefore, salt diffusion may facilitate the release of greenhouse gasses to the atmosphere and considerably affect the design of offshore and coastal infrastructure in subsea permafrost areas.



Item Type
Article
Authors
Divisions
Primary Division
Programs
Primary Topic
Research Networks
Publication Status
Published
Eprint ID
49564
DOI 10.1029/2018JF004823

Cite as
Angelopoulos, M. , Westermann, S. , Overduin, P. , Faguet, A. , Olenchenko, V. , Grosse, G. and Grigoriev, M. N. (2019): Heat and salt flow in subsea permafrost modeled with CryoGRID2 , Journal of Geophysical Research-Earth Surface, 124 (4), pp. 920-937 . doi: 10.1029/2018JF004823


Download
[thumbnail of Angelopoulos_et_al_2019_JGR.pdf]
Preview
PDF
Angelopoulos_et_al_2019_JGR.pdf

Download (2MB) | Preview

Share
Add to AnyAdd to TwitterAdd to FacebookAdd to LinkedinAdd to PinterestAdd to Email


Citation

Geographical region

Research Platforms
N/A

Campaigns
Arctic Land Expeditions > RU-Land_2017_Lena_Bykovsky

Funded by
info:eu-repo/grantAgreement/EC/FP7/338335


Actions
Edit Item Edit Item