Effects of Aerosols on Gross Primary Production from Ecosystems to the Globe

Round 1

Reviewer 1 Report

First of all, please accept my apologies for delaying in revision. The paper deals with an interesting analysis of the influence of aerosols on gross primary production on a global scale. The paper is fluent, on a remarkable level. Except for minor comments listed below, the only major flaws here are used data on various spatial and temporal scales which can have an influence on accuracy. Also, the meteorological results here should be based on chemistry simulations (meteorological models coupled with chemistry) in order to have more realistic information regarding aerosols and cloud thickness. However, the authors are aware of the problems, they were tackled and further explained, and therefore after some minor corrections, the presented manuscript merits publication in the journal Remote Sensing.

General comments:

Increase labels on the figures, and increase the size and resolution of the figures.

Minor comments:

Ln 130. How is maximum light efficiency calculated?

Ln 224. For the discussion purposes later in the manuscript, it would be good to insert figures from the MERRA dataset such as clouds thickness, temperature, and precipitation. Does the different type of precipitation have an influence, and what is the correlation between precipitation and GPP? Can the inclusion of meteorological conditions improve the AOD LUE model?

Ln 237. It would be also interesting to see time series of trends for a particular area of interest, not the entire globe.

Ln 274. Same comment here, would be interesting to see results over particular areas where the sites were located. To many dots are on the graph, it is hard to make a decent comparison (as the differences are low).

Ln 288. What is a key factor in different vegetation types that have a significant influence on the results?

Ln 311. Please elaborate more on various responses to aerosols. What is a key mechanism for a various responses?

 

Author Response

Please see the attachment.

Author Response File: Author Response.docx

Reviewer 2 Report

General comment

 

The paper reports a study of the effects of aerosols on gross primary production in different ecosystems including AOD in modelling of GPP. The topic is interesting and suitable for the Journal. However, there are some aspects not very clear or not completely discussed (see my specific points) and I suggest to consider the paper for publication after a revision addressing these aspects.

 

Specific comments

 

I was not able to find any supplementary material in the submission even if this is mentioned in the paper.

 

PAR should be defined the first time that it is used in both the abstract and the text.

 

Line 55. Better the GPP rather than in GPP.

 

In the introduction it should be mentioned if aerosol could or could not influence GPP because of its deposition on leaves.

 

Line 99. How many sites in the evergreen broadleaf forests? In addition, it should be made a little clear why here it is reported that there are 10 types but only 4 are mentioned. In Table 1 it should be added a column with the explanation of the acronym even because Table S1 is not present.

 

Figure 7 has more than 10 types of classes, why? I suggest to use the same classification in all the paper.

 

Line 108. What do you mean by aggregated? Average values?

 

Line 103. Apex for m3 and subscript for emax.

 

Equation (1). What is F(Ts,Ws)?

 

Line 175. “effectively data the status” is not clear.

 

Figure 2 and related text. What do you mean by spatial distribution from 2000 to 2014? It is an average values through the five years?

 

Lines 189-192. Here it is mentioned the year 2019, however, if I have well understood measurements are taken until 2014. Please correct the inconsistency. The same for the caption of Figure 6.

 

Line 249. Better “when Df is half of Vmax (i.e. 0.3)”.

 

Caption of Table 1. Please eliminate “This is a table”.

 

Lines 311-312. This is not clear, why you mention both positive and negative in a total values? The same problem is ion Figure 7. The total should be total effect that could be positive, negative, or negligible but using two bars is not useful. In addition, it is necessary to discuss this aspect. It seems that several sites have positive effect and several others have negative effect so that the global average could be almost zero. This aspect should be discussed and correction applied to conclusions (lines 455-456) if the global effect is really low.

 

Caption of Figure 7. The acronyms are not understandable.

 

Lines 447-448. It seems not correct. Likely it should be the “…originals model (EC-LUE), the new model (AOD-LUE)…”.

Author Response

Please see the attachment.

Author Response File: Author Response.docx

Reviewer 3 Report

I have no major comments. Some figures with maps are sometimes not legible in print though.

Author Response

Thanks for your suggestion, the figures with maps have been adjusted as requested.

Author Response File: Author Response.docx

Round 2

Reviewer 2 Report

Authors answered to my questions and improved the paper during revision. I suggest to accept it for publication in the current form.

This manuscript is a resubmission of an earlier submission. The following is a list of the peer review reports and author responses from that submission.