Upscaling Northern Peatland CO₂ Fluxes Using Satellite Remote Sensing Data

Round 1

Reviewer 1 Report

The manuscript introduces a method for peatland carbon flux estimation by upscaling in-situ flux with high-resolution remote sensing data. Overall, the paper is well organized and clearly presented. I have some comments as follows:

(1)    In the abstract, Line 30-31, I think only showing R2 is not enough, because R2 only indicates a correlation, you should also show NRMSE, which indicates the value biases. I prefer to give an average value of R2, not the range;

(2)    Lines 340-343, NDWI-based water scalar is not effective for 3 other sites, is it because these sites are not water limited? Can you provide some explanation?

(3)    It seems the model cannot work well for the interannual variations of carbon fluxes, for example, in Figure 4e, the interannual variations of the estimated GPP are quite different from these of EC fluxes. Can you give some explanation or add the necessary discussion?

(4)    Also Figure 4, it seems the proposed model under- or overestimates GPP quite much in some sites, can you further improve it (for example by adding limiting factors on carbon fluxes), which could eventually help to improve the simulation capacity on the interannual variations of carbon fluxes. Is it limited by the quality of current available remote sensing data?

(5)    For RE, you also need to consider the problems mentioned above (3 & 4). The improvement on GPP and RE estimates would finally help to improve the NEE estimate, which currently works not satisfactory;

(6)    About NEE, suggest adding discussion about the way forward to improve its estimate;

(7)    In the GPP model, LST is directly multiplied with other terms, it is different from the way used for water limiting factor (Ws) which is a scalar and not a physical variable. How do you think about using normalized LST with LSTmax and LSTmin?  Or similar way as the MOD17 algorithm?

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 2 Report

The manuscript presents the results of the original studies connected with developing of empirical models of the CO2 balance, gross primary production and ecosystem respiration (ER) for upscaling CO2 fluxes with remotely sensed data. The material presented in the manuscript is relevant, based on original data and will be of interest to the scientific community. The authors approached the work on the manuscript very conscientiously. For our view, the manuscript will need some minor revision before it can be accepted for publication.

I have made some specific comments below:

1. Line 36. Please delete semicolon after word “analysis” ;
2. Table 1. For our view information in column, “Biome” is not Biome. Please correct.
3. http://www.icos-sweden.se/station_stordalen.html does not work, please change to Abisko-Stordalen | ICOS Sweden (icos-sweden.se)
4. The information about EC towers height (m) for our view have to delete from Table 1. It will be better to create one Table more in the Manuscript to describe the EC measurements including the towers height.
5. The conclusions have to make shortly and clearer.

Comments for author File: Comments.pdf

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

Thanks for the authors' careful revisions and all the issues raised early have been well addressed. I suggest publishing it in the current form.