Simulated high-latitude soil thermal dynamics during the past 4 decades
Soil temperature (<i>T</i><sub>s</sub>) change is a key indicator of the dynamics of permafrost. On seasonal and interannual timescales, the variability of <i>T</i><sub>s</sub> determines the active-layer depth, which regulates hydrological soil proper...
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Copernicus Publications
2016-01-01
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| Series: | The Cryosphere |
| Online Access: | http://www.the-cryosphere.net/10/179/2016/tc-10-179-2016.pdf |
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| author | S. Peng P. Ciais G. Krinner T. Wang I. Gouttevin A. D. McGuire D. Lawrence E. Burke X. Chen B. Decharme C. Koven A. MacDougall A. Rinke K. Saito W. Zhang R. Alkama T. J. Bohn C. Delire T. Hajima D. Ji D. P. Lettenmaier P. A. Miller J. C. Moore B. Smith T. Sueyoshi |
| author_facet | S. Peng P. Ciais G. Krinner T. Wang I. Gouttevin A. D. McGuire D. Lawrence E. Burke X. Chen B. Decharme C. Koven A. MacDougall A. Rinke K. Saito W. Zhang R. Alkama T. J. Bohn C. Delire T. Hajima D. Ji D. P. Lettenmaier P. A. Miller J. C. Moore B. Smith T. Sueyoshi |
| author_sort | S. Peng |
| collection | DOAJ |
| description | Soil temperature (<i>T</i><sub>s</sub>) change is a key indicator of the dynamics of
permafrost. On seasonal and interannual timescales, the variability of
<i>T</i><sub>s</sub> determines the active-layer depth, which regulates hydrological soil
properties and biogeochemical processes. On the multi-decadal scale,
increasing <i>T</i><sub>s</sub> not only drives permafrost thaw/retreat but can also
trigger and accelerate the decomposition of soil organic carbon. The
magnitude of permafrost carbon feedbacks is thus closely linked to the rate
of change of soil thermal regimes. In this study, we used nine process-based
ecosystem models with permafrost processes, all forced by different
observation-based climate forcing during the period 1960–2000, to
characterize the warming rate of <i>T</i><sub>s</sub> in permafrost regions. There is a
large spread of <i>T</i><sub>s</sub> trends at 20 cm depth across the models, with trend
values ranging from 0.010 ± 0.003 to 0.031 ± 0.005 °C yr<sup>−1</sup>. Most models show smaller increase in
<i>T</i><sub>s</sub> with increasing depth. Air temperature (<i>T</i>sub>a</sub>) and longwave
downward radiation (LWDR) are the main drivers of <i>T</i><sub>s</sub> trends, but their
relative contributions differ amongst the models. Different trends of LWDR
used in the forcing of models can explain 61 % of their differences in
<i>T</i><sub>s</sub> trends, while trends of <i>T</i><sub>a</sub> only explain 5 % of the
differences in <i>T</i><sub>s</sub> trends. Uncertain climate forcing contributes a
larger uncertainty in <i>T</i><sub>s</sub> trends (0.021 ± 0.008 °C yr<sup>−1</sup>, mean ± standard deviation) than the uncertainty of model
structure (0.012 ± 0.001 °C yr<sup>−1</sup>), diagnosed from the
range of response between different models, normalized to the same forcing.
In addition, the loss rate of near-surface permafrost area, defined as total
area where the maximum seasonal active-layer thickness (ALT) is less than 3 m loss
rate, is found to be significantly correlated with the magnitude of
the trends of <i>T</i><sub>s</sub> at 1 m depth across the models (<i>R</i> = −0.85, <i>P</i> = 0.003),
but not with the initial total near-surface permafrost area (<i>R</i> = −0.30,
<i>P</i> = 0.438). The sensitivity of the total boreal near-surface permafrost area
to <i>T</i><sub>s</sub> at 1 m is estimated to be of −2.80 ± 0.67 million km<sup>2</sup> °C<sup>−1</sup>. Finally, by using two long-term LWDR data sets and
relationships between trends of LWDR and <i>T</i><sub>s</sub> across models, we infer an
observation-constrained total boreal near-surface permafrost area decrease
comprising between 39 ± 14 × 10<sup>3</sup> and 75 ± 14 × 10<sup>3</sup> km<sup>2</sup> yr<sup>−1</sup> from 1960 to 2000. This corresponds
to 9–18 % degradation of the current permafrost area. |
| first_indexed | 2024-12-21T19:30:10Z |
| format | Article |
| id | doaj.art-f596bdf8d6b74650ac9b35db103c6bcb |
| institution | Directory Open Access Journal |
| issn | 1994-0416 1994-0424 |
| language | English |
| last_indexed | 2024-12-21T19:30:10Z |
| publishDate | 2016-01-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | The Cryosphere |
| spelling | doaj.art-f596bdf8d6b74650ac9b35db103c6bcb2022-12-21T18:52:44ZengCopernicus PublicationsThe Cryosphere1994-04161994-04242016-01-0110117919210.5194/tc-10-179-2016Simulated high-latitude soil thermal dynamics during the past 4 decadesS. Peng0P. Ciais1G. Krinner2T. Wang3I. Gouttevin4A. D. McGuire5D. Lawrence6E. Burke7X. Chen8B. Decharme9C. Koven10A. MacDougall11A. Rinke12K. Saito13W. Zhang14R. Alkama15T. J. Bohn16C. Delire17T. Hajima18D. Ji19D. P. Lettenmaier20P. A. Miller21J. C. Moore22B. Smith23T. Sueyoshi24UJF–Grenoble 1/CNRS, Laboratoire de Glaciologie et Géophysique de l'Environnement (LGGE), 38041 Grenoble, FranceLaboratoire des Sciences du Climat et de l'Environnement (LSCE), CEA-CNRS-UVSQ, 91191 Gif-sur-Yvette, FranceUJF–Grenoble 1/CNRS, Laboratoire de Glaciologie et Géophysique de l'Environnement (LGGE), 38041 Grenoble, FranceUJF–Grenoble 1/CNRS, Laboratoire de Glaciologie et Géophysique de l'Environnement (LGGE), 38041 Grenoble, FranceUJF–Grenoble 1/CNRS, Laboratoire de Glaciologie et Géophysique de l'Environnement (LGGE), 38041 Grenoble, FranceUS Geological Survey, Alaska Cooperative Fish and Wildlife Research Unit, University of Alaska Fairbanks, Fairbanks, AK, USANational Center for Atmospheric Research, Boulder, CO, USAMet Office Hadley Centre, FitzRoy Road, Exeter EX1 3PB, UKDepartment of Civil and Environmental Engineering, University of Washington, Seattle, WA, USACNRM-GAME, Unitémixte de recherche CNRS/Meteo-France (UMR 3589), 42 avCoriolis, 31057 Toulouse CEDEX, FranceLawrence Berkeley National Laboratory, Berkeley, CA, USASchool of Earth and Ocean Sciences, University of Victoria, Victoria, BC, CanadaCollege of Global Change and Earth System Science, Beijing Normal University, Beijing, ChinaResearch Institute for Global Change, Japan Agency for Marine-Earth Science and Technology, Yokohama, Kanagawa, JapanDepartment of Physical Geography and Ecosystem Science, Lund University, Sölvegatan 12, 223 62 Lund, SwedenCNRM-GAME, Unitémixte de recherche CNRS/Meteo-France (UMR 3589), 42 avCoriolis, 31057 Toulouse CEDEX, FranceSchool of Earth and Space Exploration, Arizona State University, Tempe, AZ, USACNRM-GAME, Unitémixte de recherche CNRS/Meteo-France (UMR 3589), 42 avCoriolis, 31057 Toulouse CEDEX, FranceResearch Institute for Global Change, Japan Agency for Marine-Earth Science and Technology, Yokohama, Kanagawa, JapanCollege of Global Change and Earth System Science, Beijing Normal University, Beijing, ChinaDepartment of Civil and Environmental Engineering, University of Washington, Seattle, WA, USADepartment of Physical Geography and Ecosystem Science, Lund University, Sölvegatan 12, 223 62 Lund, SwedenCollege of Global Change and Earth System Science, Beijing Normal University, Beijing, ChinaDepartment of Physical Geography and Ecosystem Science, Lund University, Sölvegatan 12, 223 62 Lund, SwedenNational Institute of Polar Research, Tachikawa, Tokyo, JapanSoil temperature (<i>T</i><sub>s</sub>) change is a key indicator of the dynamics of permafrost. On seasonal and interannual timescales, the variability of <i>T</i><sub>s</sub> determines the active-layer depth, which regulates hydrological soil properties and biogeochemical processes. On the multi-decadal scale, increasing <i>T</i><sub>s</sub> not only drives permafrost thaw/retreat but can also trigger and accelerate the decomposition of soil organic carbon. The magnitude of permafrost carbon feedbacks is thus closely linked to the rate of change of soil thermal regimes. In this study, we used nine process-based ecosystem models with permafrost processes, all forced by different observation-based climate forcing during the period 1960–2000, to characterize the warming rate of <i>T</i><sub>s</sub> in permafrost regions. There is a large spread of <i>T</i><sub>s</sub> trends at 20 cm depth across the models, with trend values ranging from 0.010 ± 0.003 to 0.031 ± 0.005 °C yr<sup>−1</sup>. Most models show smaller increase in <i>T</i><sub>s</sub> with increasing depth. Air temperature (<i>T</i>sub>a</sub>) and longwave downward radiation (LWDR) are the main drivers of <i>T</i><sub>s</sub> trends, but their relative contributions differ amongst the models. Different trends of LWDR used in the forcing of models can explain 61 % of their differences in <i>T</i><sub>s</sub> trends, while trends of <i>T</i><sub>a</sub> only explain 5 % of the differences in <i>T</i><sub>s</sub> trends. Uncertain climate forcing contributes a larger uncertainty in <i>T</i><sub>s</sub> trends (0.021 ± 0.008 °C yr<sup>−1</sup>, mean ± standard deviation) than the uncertainty of model structure (0.012 ± 0.001 °C yr<sup>−1</sup>), diagnosed from the range of response between different models, normalized to the same forcing. In addition, the loss rate of near-surface permafrost area, defined as total area where the maximum seasonal active-layer thickness (ALT) is less than 3 m loss rate, is found to be significantly correlated with the magnitude of the trends of <i>T</i><sub>s</sub> at 1 m depth across the models (<i>R</i> = −0.85, <i>P</i> = 0.003), but not with the initial total near-surface permafrost area (<i>R</i> = −0.30, <i>P</i> = 0.438). The sensitivity of the total boreal near-surface permafrost area to <i>T</i><sub>s</sub> at 1 m is estimated to be of −2.80 ± 0.67 million km<sup>2</sup> °C<sup>−1</sup>. Finally, by using two long-term LWDR data sets and relationships between trends of LWDR and <i>T</i><sub>s</sub> across models, we infer an observation-constrained total boreal near-surface permafrost area decrease comprising between 39 ± 14 × 10<sup>3</sup> and 75 ± 14 × 10<sup>3</sup> km<sup>2</sup> yr<sup>−1</sup> from 1960 to 2000. This corresponds to 9–18 % degradation of the current permafrost area.http://www.the-cryosphere.net/10/179/2016/tc-10-179-2016.pdf |
| spellingShingle | S. Peng P. Ciais G. Krinner T. Wang I. Gouttevin A. D. McGuire D. Lawrence E. Burke X. Chen B. Decharme C. Koven A. MacDougall A. Rinke K. Saito W. Zhang R. Alkama T. J. Bohn C. Delire T. Hajima D. Ji D. P. Lettenmaier P. A. Miller J. C. Moore B. Smith T. Sueyoshi Simulated high-latitude soil thermal dynamics during the past 4 decades The Cryosphere |
| title | Simulated high-latitude soil thermal dynamics during the past 4 decades |
| title_full | Simulated high-latitude soil thermal dynamics during the past 4 decades |
| title_fullStr | Simulated high-latitude soil thermal dynamics during the past 4 decades |
| title_full_unstemmed | Simulated high-latitude soil thermal dynamics during the past 4 decades |
| title_short | Simulated high-latitude soil thermal dynamics during the past 4 decades |
| title_sort | simulated high latitude soil thermal dynamics during the past 4 decades |
| url | http://www.the-cryosphere.net/10/179/2016/tc-10-179-2016.pdf |
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