TY  - JOUR
A1  - Angelopoulos, Michael
A1  - Westermann, Sebastian
A1  - Overduin, Pier Paul
A1  - Faguet, Alexey
A1  - Olenchenko, Vladimir
A1  - Grosse, Guido
A1  - Grigoriev, Mikhail N.
T1  - Heat and salt flow in subsea permafrost modeled with CryoGRID2
JF  - Journal of geophysical research : Earth surface
N2  - 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 0.25m/year was 16.7 m below the seabed 350m 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 15-20m below the seabed at 350m 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.
KW  - subsea permafrost
KW  - salt diffusion
KW  - CryoGRID
KW  - Lena Delta
KW  - Bykovsky Peninsula
KW  - electrical resistivity
Y1  - 2019
U6  - https://doi.org/10.1029/2018JF004823
SN  - 2169-9003
SN  - 2169-9011
VL  - 124
IS  - 4
SP  - 920
EP  - 937
PB  - American Geophysical Union
CY  - Hoboken
ER  -