Effects of stratified active layers on high-altitude permafrost warming:
a case study on the Qinghai–Tibet Plateau

Pan, Xicai; Li, Yanping; Yu, Qihao; Shi, Xiaogang; Yang, Daqing; Roth, Kurt

doi:https://doi.org/10.5194/tc-10-1591-2016

Articles | Volume 10, issue 4

https://doi.org/10.5194/tc-10-1591-2016

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

https://doi.org/10.5194/tc-10-1591-2016

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

Articles | Volume 10, issue 4

Research article

|

25 Jul 2016

Research article |

| 25 Jul 2016

Effects of stratified active layers on high-altitude permafrost warming: a case study on the Qinghai–Tibet Plateau

Xicai Pan, Yanping Li, Qihao Yu, Xiaogang Shi, Daqing Yang, and Kurt Roth

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Final revised paper (published on 25 Jul 2016)
Preprint (discussion started on 18 Jan 2016)

Interactive discussion

Status: closed

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

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RC1: 'Review of Pan et al.', Anonymous Referee #1, 19 Jan 2016
- AC1: 'Reply for comments', Xicai Pan, 18 Mar 2016
RC2: 'Review of the Manuscript : Effects of Stratified Active Layers on the High-Altitude Permafrost Warming: A Case Study on the Qinghai-Tibet Plateau', Anonymous Referee #2, 17 Feb 2016
- AC2: 'Reply for comments', Xicai Pan, 18 Mar 2016
RC3: 'Review of the paper by Pan et al.', Stefano Endrizzi, 04 Apr 2016
- AC3: 'Response', Xicai Pan, 14 Jun 2016

Peer-review completion

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

AR by Svenja Lange on behalf of the Authors (10 May 2016) Author's response

ED: Referee Nomination & Report Request started (27 May 2016) by Martin Schneebeli

RR by Anonymous Referee #1 (06 Jun 2016)

Suggestions for revision or reasons for rejection

The manuscript seems almost ready for publication. I just have a few minor comments.

P1, L14, ‘smaller’ should be ‘lower’

P2, L6-7, why is the warming rate given per decade at the first of the sentence and then per year later on? Also, these two presented rates only differ by 0.01 C/yr.

P2, L9-11, this is an awkward and confusing sentence

P2, L20, I’d delete ‘in addition to the soil thermal properties’ as it is not needed in this sentence, and the sentence has iffy structure

P2, L20-22, as I noted last time, and the authors insufficiently addressed, it is not really appropriate to say that permafrost has diurnal forcing. Permafrost does not freeze and thaw on a daily basis. This sentence is confusing.

P2, L34, change ‘highly demanded’ to ‘required’ and ‘facilitate’ to ‘enable’
Throughout the manuscript: I’d say ‘rapid permafrost warming’ not ‘quick permafrost warming’

This is just a comment and the authors do not need to change anything, but I remain skeptical that analytical models (at least in theory) cannot address the seasonal moisture content/thermal conductivity and layering issue that the authors address. As reviewed by Walvoord and Kurylyk (2016), Stefan equation modifications have been proposed to address soil layering, changing moisture content, sensible heat affects, and two-directional heat transfer. These algorithms can often be combined, and thus many of the analytical assumptions can be relaxed.

Walvoord MA, Kurylyk BL. 2016. Hydrologic impacts of thawing permafrost – A review. Vadose Zone Journal, DOI: 10.2136/vzj2016.01.0010

P3, L29, change ‘Thereby’ to ‘Thus’

P4, L1, delete ‘They were’ and combine the 2 sentences into 1.

P4, L23, delete ‘. They are’ and add a colon after ‘drilling’ (i.e. combine into one sentence)

P4, L26 move ‘solely’ after ‘to’

P8, L8, change ‘is rarely addressed’ to ‘has been rarely addressed’

P8, L31, change ‘not well accurate in general’ to ‘not generally accurate’

P10, L3, change ‘of water’s’ to ‘that of water’

P10, L3-4, this statement is not true. It assumes a porosity of 1 (and also ignores changes in the heat capacity of ice vs. water). It is not needed, so just delete it.

P10, L6, insert ‘it is’ after ‘instance’

P11, L16, change ‘sparsely’ to ‘sparse’

P11, L18, this is not really the right use of the term ‘indispensable’. It should be something like ‘instrumental’

P11, L21, for this point I would insert ‘negative’ after ‘normal’ and ‘(≥ 1)’ after ‘reversed’. I’d also delete “namely close 1.0 or even higher, given such a weather pattern and soil properties”

P11, L24, change ‘facilitating to raise’ to ‘raising’

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RR by Anonymous Referee #2 (20 Jun 2016)

ED: Publish subject to minor revisions (Editor review) (28 Jun 2016) by Martin Schneebeli

AR by Xicai Pan on behalf of the Authors (30 Jun 2016) Author's response Manuscript

ED: Publish as is (05 Jul 2016) by Martin Schneebeli

Short summary

Using a 9-year dataset in conjunction with a process-based model, we verify that the common assumption of a considerably smaller thermal conductivity in the thawed season than the frozen season is not valid at a site with a stratified active layer on the Qinghai–Tibet Plateau (QTP). The unique hydraulic and thermal mechanism in the active layer challenges the concept of thermal offset used in conceptual permafrost models and hints at the reason for rapid permafrost warming on the QTP.