Numerical Assessments of Excess Ice Impacts on Permafrost and Greenhouse Gases in a Siberian Tundra Site Under a Warming Climate
Excess ice that exists in forms such as ice lenses and wedges in permafrost soils is vulnerable to climate warming. Here, we incorporated a simple representation of excess ice in a coupled hydrological and biogeochemical model (CHANGE) to assess how excess ice affects permafrost thaw and associated...
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doaj-4fd263e98a8d49c4a1ba38793808bbef2021-09-22T05:48:10ZengFrontiers Media S.A.Frontiers in Earth Science2296-64632021-09-01910.3389/feart.2021.704447704447Numerical Assessments of Excess Ice Impacts on Permafrost and Greenhouse Gases in a Siberian Tundra Site Under a Warming ClimateHotaek Park0Hotaek Park1Alexander N. Fedorov2Pavel Konstantinov3Tetsuya Hiyama4Institute of Arctic Climate and Environmental Research, JAMSTEC, Yokosuka, JapanInstitute for Space-Earth Environmental Research, Nagoya University, Nagoya, JapanMelnikov Permafrost Institute, Siberian Branch of the Russian Academy of Sciences, Yakutsk, RussiaMelnikov Permafrost Institute, Siberian Branch of the Russian Academy of Sciences, Yakutsk, RussiaInstitute for Space-Earth Environmental Research, Nagoya University, Nagoya, JapanExcess ice that exists in forms such as ice lenses and wedges in permafrost soils is vulnerable to climate warming. Here, we incorporated a simple representation of excess ice in a coupled hydrological and biogeochemical model (CHANGE) to assess how excess ice affects permafrost thaw and associated hydrologic responses, and possible impacts on carbon dioxide and methane (CH4) fluxes. The model was used to simulate a moss-covered tundra site in northeastern Siberia with various vertical initializations of excess ice under a future warming climate scenario. Simulations revealed that the warming climate induced deepening of the active layer thickness (ALT) and higher vegetation productivity and heterotrophic respiration from permafrost soil. Meanwhile, excess ice temporarily constrained ALT deepening and thermally stabilized permafrost because of the highest latent heat effect obtained under these conditions. These effects were large under conditions of high excess ice content distributed in deeper soil layers, especially when covered by moss and thinner snow. Once ALT reached to the layer of excess ice, it was abruptly melted, leading to ground surface subsidence over 15–20 years. The excess ice meltwater caused deeper soil to wet and contributed to talik formation. The anaerobic wet condition was effective to high CH4 emissions. However, as the excess ice meltwater was connected to the subsurface flow, the resultant lower water table limited the CH4 efflux. These results provide insights for interactions between warming climate, permafrost excess ice, and carbon and CH4 fluxes in well-drained conditions.https://www.frontiersin.org/articles/10.3389/feart.2021.704447/fullland surface modelsubsurface flowsubsidencepermafrost excess icecarbon and methane fluxes |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Hotaek Park Hotaek Park Alexander N. Fedorov Pavel Konstantinov Tetsuya Hiyama |
spellingShingle |
Hotaek Park Hotaek Park Alexander N. Fedorov Pavel Konstantinov Tetsuya Hiyama Numerical Assessments of Excess Ice Impacts on Permafrost and Greenhouse Gases in a Siberian Tundra Site Under a Warming Climate Frontiers in Earth Science land surface model subsurface flow subsidence permafrost excess ice carbon and methane fluxes |
author_facet |
Hotaek Park Hotaek Park Alexander N. Fedorov Pavel Konstantinov Tetsuya Hiyama |
author_sort |
Hotaek Park |
title |
Numerical Assessments of Excess Ice Impacts on Permafrost and Greenhouse Gases in a Siberian Tundra Site Under a Warming Climate |
title_short |
Numerical Assessments of Excess Ice Impacts on Permafrost and Greenhouse Gases in a Siberian Tundra Site Under a Warming Climate |
title_full |
Numerical Assessments of Excess Ice Impacts on Permafrost and Greenhouse Gases in a Siberian Tundra Site Under a Warming Climate |
title_fullStr |
Numerical Assessments of Excess Ice Impacts on Permafrost and Greenhouse Gases in a Siberian Tundra Site Under a Warming Climate |
title_full_unstemmed |
Numerical Assessments of Excess Ice Impacts on Permafrost and Greenhouse Gases in a Siberian Tundra Site Under a Warming Climate |
title_sort |
numerical assessments of excess ice impacts on permafrost and greenhouse gases in a siberian tundra site under a warming climate |
publisher |
Frontiers Media S.A. |
series |
Frontiers in Earth Science |
issn |
2296-6463 |
publishDate |
2021-09-01 |
description |
Excess ice that exists in forms such as ice lenses and wedges in permafrost soils is vulnerable to climate warming. Here, we incorporated a simple representation of excess ice in a coupled hydrological and biogeochemical model (CHANGE) to assess how excess ice affects permafrost thaw and associated hydrologic responses, and possible impacts on carbon dioxide and methane (CH4) fluxes. The model was used to simulate a moss-covered tundra site in northeastern Siberia with various vertical initializations of excess ice under a future warming climate scenario. Simulations revealed that the warming climate induced deepening of the active layer thickness (ALT) and higher vegetation productivity and heterotrophic respiration from permafrost soil. Meanwhile, excess ice temporarily constrained ALT deepening and thermally stabilized permafrost because of the highest latent heat effect obtained under these conditions. These effects were large under conditions of high excess ice content distributed in deeper soil layers, especially when covered by moss and thinner snow. Once ALT reached to the layer of excess ice, it was abruptly melted, leading to ground surface subsidence over 15–20 years. The excess ice meltwater caused deeper soil to wet and contributed to talik formation. The anaerobic wet condition was effective to high CH4 emissions. However, as the excess ice meltwater was connected to the subsurface flow, the resultant lower water table limited the CH4 efflux. These results provide insights for interactions between warming climate, permafrost excess ice, and carbon and CH4 fluxes in well-drained conditions. |
topic |
land surface model subsurface flow subsidence permafrost excess ice carbon and methane fluxes |
url |
https://www.frontiersin.org/articles/10.3389/feart.2021.704447/full |
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