A simple time-stepping scheme to simulate leaf area index, phenology, and gross primary production across deciduous broadleaf forests in the eastern United States

Xin, Qinchuan; Dai, Yongjiu; Liu, Xiaoping

doi:https://doi.org/10.5194/bg-16-467-2019

Articles | Volume 16, issue 2

https://doi.org/10.5194/bg-16-467-2019

© Author(s) 2019. This work is distributed under
the Creative Commons Attribution 4.0 License.

https://doi.org/10.5194/bg-16-467-2019

© Author(s) 2019. This work is distributed under
the Creative Commons Attribution 4.0 License.

Articles | Volume 16, issue 2

Research article

|

25 Jan 2019

Research article |

| 25 Jan 2019

A simple time-stepping scheme to simulate leaf area index, phenology, and gross primary production across deciduous broadleaf forests in the eastern United States

Qinchuan Xin, Yongjiu Dai, and Xiaoping Liu

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Final revised paper (published on 25 Jan 2019)
Preprint (discussion started on 03 Sep 2018)

Interactive discussion

Status: closed

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

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RC1: 'Referee comments', Anonymous Referee #1, 27 Sep 2018
- AC1: 'Responses to the reviewer#1's comments', Qinchuan Xin, 13 Nov 2018
RC2: 'Manuscript needs work', Anonymous Referee #2, 04 Oct 2018
- AC2: 'responses to the reviewer's comments', Qinchuan Xin, 13 Nov 2018

Peer-review completion

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

ED: Reconsider after major revisions (13 Nov 2018) by Alexey V. Eliseev

AR by Qinchuan Xin on behalf of the Authors (13 Nov 2018) Author's response Manuscript

ED: Referee Nomination & Report Request started (14 Nov 2018) by Alexey V. Eliseev

RR by Anonymous Referee #1 (18 Nov 2018)

RR by Anonymous Referee #2 (04 Dec 2018)

Suggestions for revision or reasons for rejection

I appreciate authors’ efforts in revising their manuscript. However, I am sorry but I still find that the manuscript falls short of being ready for publication. I have new concerns after reading the manuscript and I summarize my primary concerns below. I am also attaching an annotated version of the manuscript in which authors can find other minor comments.

At a number of places in the manuscript, the authors have stressed that their scheme can be used for modeling leaf phenology in land surface models like the community land model (CLM). However, one thing that is being neglected here is that models like CLM are able to simulate leaf area index as a function of atmospheric CO2 concentration. In authors’ approach the variable m=LAI/GPP is a constant and calculated using present-day LAI and GPP. As such then, it is not possible to use this approach in land surface models that are designed for application for future climate and CO2 scenarios.

I am uncomfortable with authors’ comparison of their results with those obtained using the moving average model. The moving average model cannot clearly be used in current generation of land surface models which determine leaf area index prognostically. I suspect the reason the authors have compared results from their new time stepping method to those obtained using the moving average method because this is what they did in the past and are more comfortable with their moving average method. However, this does not mean that the results from the moving average method should be used as a benchmark.

The justification for developing a simple model is still not strong enough in the revised manuscript.

In Figure 6 something doesn’t seem right with the GLASS LAI data. Notice that in all panels (a, b, and c) the interannual variability in SOS, EOS, and GSL is much larger before the year 2000.

In summary, this manuscript needs to be written in such a way so that its primary argument (that a simple prognostic LAI modeling scheme can be used in complex land surface models) can be brought out much more clearly. In its current form, this message is not brought out properly and leaves a reader confused. Perhaps, another reviewer is needed who can look at the manuscript with a fresh set of eyes.

Referee Report: PDF

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ED: Publish subject to minor revisions (review by editor) (04 Dec 2018) by Alexey V. Eliseev

AR by Qinchuan Xin on behalf of the Authors (16 Dec 2018) Author's response Manuscript

ED: Publish as is (19 Dec 2018) by Alexey V. Eliseev

Short summary

Terrestrial biosphere models that simulate both leaf dynamics and canopy photosynthesis are required to understand vegetation–climate interactions. A time-stepping scheme is proposed to simulate leaf area index, phenology, and gross primary production via climate variables. The method performs well on simulating deciduous broadleaf forests across the eastern United States; it provides a simplified and improved version of the growing production day model for use in land surface modeling.