Heat and Salt Flow in Subsea Permafrost Modeled with CryoGRID2

Michael Angelopoulos, Sebastian Westermann, Paul Overduin, Alexey Faguet, Vladimir Olenchenko, Guido Grosse, Mikhail N. Grigoriev

Research output: Contribution to journalArticlepeer-review

12 Citations (Scopus)

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.

Original languageEnglish
Pages (from-to)920-937
Number of pages18
JournalJournal of Geophysical Research
Volume124
Issue number4
DOIs
Publication statusPublished - Apr 2019

Keywords

  • Bykovsky Peninsula
  • CryoGRID
  • electrical resistivity
  • Lena Delta
  • salt diffusion
  • subsea permafrost
  • SEDIMENTS
  • LENA RIVER DELTA
  • NORTHERN SIBERIA
  • LAPTEV SEA REGION
  • SURFACE-ENERGY BALANCE
  • THERMOKARST
  • SUBMARINE PERMAFROST
  • SHELF
  • DEGRADATION
  • POLYGONAL TUNDRA SITE

Fingerprint Dive into the research topics of 'Heat and Salt Flow in Subsea Permafrost Modeled with CryoGRID2'. Together they form a unique fingerprint.

Cite this