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| Titel |
Permafrost degradation and associated soil subsidence assessed in offline simulation with a soil model under the SRES A2 scenario |
| VerfasserIn |
M. M. Arzhanov, P. F. Demchenko, A. V. Eliseev, I. I. Mokhov |
| Konferenz |
EGU General Assembly 2009
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 11 (2009) |
| Datensatznummer |
250025162
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| Zusammenfassung |
| Permafrost degradation and associated soil subsidence is assessed in offline simulations with
a soil model developed at the A.M. Obukhov Institute of Atmospheric Physics RAS.
This model is forced by the monthly mean atmospheric fields simulated by the
ECHAM5/MPI–OM general circulation model under the anthropogenic scenario SRES A2.
In the late 20th century, modelled permafrost extents over 17.0 mln sq km. This area
shrinks to 3.4 mln. sq km to the end of the 21st century. In regions where permafrost
remains in the late 21st century, active layer thickness increases by 0.6–0.8 m. Most marked
permafrost degradation is simulated for the last decades of the 21st century. However,
subsurface permafrost turns to relic form even in decade 2010–2020 in the regions near the
contemporary permafrost southern boundary in the Northern Hemisphere. Permafrost
degradation is accompanied by formation of taliks which penetrate to the depth of several
metres in a few decades.
Permafrost thaw leads to cavities in soil pores, and, in turn, to soil subsidence due to
gravity. This soil subsidence is estimated based on
( )
Ïi-
dh = (ξ2 - ξ1) 1- Ïw
where ξ1 is annual mean depth of the top of relic permafrost, ξ1 is the penetration depth of
seasonal frost, Ïi and Ïw stand for ice and water density respectively. During the second half
of the 21st century, modelled area experiencing subsidence enlarges rapidly with typical
values of vertical shifts of soil layers amounting several tens of centimetres and reaching up
to 1.2Â m locally. |
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