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Paul Miller. Foto.

Paul Miller

Universitetslektor

Paul Miller. Foto.

Model simulations of arctic biogeochemistry and permafrost extent are highly sensitive to the implemented snow scheme in LPJ-GUESS

Författare

  • Alexandra Pongracz
  • David Wårlind
  • Paul A. Miller
  • Frans Jan W. Parmentier

Summary, in English

The Arctic is warming rapidly, especially in winter, which is causing large-scale reductions in snow cover. Snow is one of the main controls on soil thermodynamics, and changes in its thickness and extent affect both permafrost thaw and soil biogeochemistry. Since soil respiration during the cold season potentially offsets carbon uptake during the growing season, it is essential to achieve a realistic simulation of the effect of snow cover on soil conditions to more accurately project the direction of arctic carbon-climate feedbacks under continued winter warming. The Lund-Potsdam-Jena General Ecosystem Simulator (LPJ-GUESS) dynamic vegetation model has used - up until now - a single layer snow scheme, which underestimated the insulation effect of snow, leading to a cold bias in soil temperature. To address this shortcoming, we developed and integrated a dynamic, multi-layer snow scheme in LPJ-GUESS. The new snow scheme performs well in simulating the insulation of snow at hundreds of locations across Russia compared to observations. We show that improving this single physical factor enhanced simulations of permafrost extent compared to an advanced permafrost product, where the overestimation of permafrost cover decreased from 10% to 5% using the new snow scheme. Besides soil thermodynamics, the new snow scheme resulted in a doubled winter respiration and an overall higher vegetation carbon content. This study highlights the importance of a correct representation of snow in ecosystem models to project biogeochemical processes that govern climate feedbacks. The new dynamic snow scheme is an essential improvement in the simulation of cold season processes, which reduces the uncertainty of model projections. These developments contribute to a more realistic simulation of arctic carbon-climate feedbacks.

Avdelning/ar

  • BECC: Biodiversity and Ecosystem services in a Changing Climate
  • MERGE: ModElling the Regional and Global Earth system
  • Institutionen för naturgeografi och ekosystemvetenskap
  • eSSENCE: The e-Science Collaboration
  • Centrum för miljö- och klimatvetenskap (CEC)

Publiceringsår

2021-10-26

Språk

Engelska

Sidor

5767-5787

Publikation/Tidskrift/Serie

Biogeosciences

Volym

18

Issue

20

Dokumenttyp

Artikel i tidskrift

Förlag

Copernicus GmbH

Ämne

  • Physical Geography

Status

Published

ISBN/ISSN/Övrigt

  • ISSN: 1726-4170