Simulated high-latitude soil thermal dynamics during  the past 4 decades

Peng, S.; Ciais, P.; Krinner, G.; Wang, T.; Gouttevin, I.; McGuire, A. D.; Lawrence, D.; Burke, E.; Chen, X.; Decharme, B.; Koven, C.; MacDougall, A.; Rinke, A.; Saito, K.; Zhang, W.; Alkama, R.; Bohn, T. J.; Delire, C.; Hajima, T.; Ji, D.; Lettenmaier, D. P.; Miller, P. A.; Moore, J. C.; Smith, B.; Sueyoshi, T.

doi:https://doi.org/10.5194/tc-10-179-2016

Articles | Volume 10, issue 1

https://doi.org/10.5194/tc-10-179-2016

© Author(s) 2016. This work is distributed under
the Creative Commons Attribution 3.0 License.

https://doi.org/10.5194/tc-10-179-2016

© Author(s) 2016. This work is distributed under
the Creative Commons Attribution 3.0 License.

Articles | Volume 10, issue 1

Research article

|

20 Jan 2016

Research article |

| 20 Jan 2016

Simulated high-latitude soil thermal dynamics during the past 4 decades

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, and T. Sueyoshi

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Final revised paper (published on 20 Jan 2016)
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Status: closed

AC: Author comment | RC: Referee comment | SC: Short comment | EC: Editor comment

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RC C862: 'Review of “Simulated high-latitude soil thermal dynamics during the past four decades” by S. Peng et al.', Anonymous Referee #1, 22 May 2015
- AC C1395: 'Reply on comments from anonymous Referee#1', S. Peng, 10 Aug 2015
RC C865: 'Review comment', Anonymous Referee #2, 25 May 2015
- AC C1396: 'Reply on comments from anonymous Referee#2', S. Peng, 10 Aug 2015

Peer-review completion

AR: Author's response | RR: Referee report | ED: Editor decision

AR by Shushi Peng on behalf of the Authors (10 Aug 2015)

ED: Referee Nomination & Report Request started (06 Oct 2015) by Tobias Bolch

RR by Anonymous Referee #1 (27 Oct 2015)

RR by Anonymous Referee #3 (02 Nov 2015)

Suggestions for revision or reasons for rejection

This study uses nine land-surface models to simulate soil temperature (Ts) in permafrost regions during the period 1960-2000. Most models are well known and used in the land surface component of Earth System Models participating CMIP5 project. The different models are using different forcing datasets for climate and other model boundary conditions. The results were used to compare trends of simulated Ts at different depths during four decades and to assess the uncertainty of modeled Ts trends. The results were also used to identify which factors were most important for driving the Ts trends and to quantify the sensitivity of changes in near-surface permafrost area to warming.

The study distinguish the uncertainty caused by assigned parameter values and model structure from the uncertainty attributable to uncertain climate forcing data, and highlight the large uncertainty in soil temperature simulations on regional and global scales in permafrost areas. Publication of this kind of paper will be very timely and beneficial for further permafrost simulations in CMIP6 and will give a better understanding of the range of uncertainty in future projections of permafrost thermal state and distribution. The revised manuscript is well written and organized. It is clearly within the scope of The Cryosphere.

I will recommend that it should be published and have only some few minor comments and suggested changes as indicated below.

P18, L413-417: I propose to clarify, for example: “In addition, important processes in permafrost regions such as the dynamics of excessive ground ice (e.g. ice wedge growth and degradation) and thermokarst lakes (formation, expansion and drainage) should be developed and evaluated in land surface models to improve the prediction of future permafrost feedbacks (e.g. van Huissteden et al., 2013; Lee et al., 2014).

P34, Table 1: The bottom boundary geothermal heat flux is assumed to be zero in 8 of the 9 models. As far as I see this is not commented and could be more clarified/discussed in e.g. section 3.2 (P12-13). E.g. Nicolsky et al. 2007 made a consideration of this.

Nicolsky, D., Romanovsky, V., Alexeev, V., and Lawrence, D.: Improved modeling of permafrost dynamics in a GCM land-surface scheme, Geophys. Res. Lett., 34, L08501, doi:10.1029/2007GL029525, 2007.

P21-22, Conclusions: To make it easier for readers that only reads the conclusions I suggest that you re-define the abbreviations for each of the variables Ts, Ta, LWDR, NSPA and regional mean Ts at their first appearance in the conclusions.

P23, L515-517: See also a recent promising modeling approach for ground temperatures using remote sensing data and reanalysis products presented by Westermann et al. 2015.

Westermann, S., Østby, T. I., Gisnås, K., Schuler, T. V., and Etzelmüller, B.: A ground temperature map of the North Atlantic permafrost region based on remote sensing and reanalysis data, The Cryosphere, 9, 1303-1319, doi:10.5194/tc-9-1303-2015, 2015.

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ED: Publish subject to minor revisions (Editor review) (12 Nov 2015) by Tobias Bolch

AR by Shushi Peng on behalf of the Authors (22 Nov 2015) Author's response Manuscript

ED: Publish as is (05 Dec 2015) by Tobias Bolch

AR by Shushi Peng on behalf of the Authors (14 Dec 2015)

Short summary

Soil temperature change is a key indicator of the dynamics of permafrost. Using nine process-based ecosystem models with permafrost processes, a large spread of soil temperature trends across the models. Air temperature and longwave downward radiation are the main drivers of soil temperature trends. Based on an emerging observation constraint method, the total boreal near-surface permafrost area decrease comprised between 39 ± 14 × 10³ and 75 ± 14 × 10³ km² yr⁻¹ from 1960 to 2000.