New Reprocessing towards Life-Time Quality-Consistent Suomi NPP OMPS Nadir Sensor Data Records (SDR): Calibration Improvements and Impact Assessments on Long-Term Quality Stability of OMPS SDR Data Sets

Round 1

Reviewer 1 Report

The authors report on the calibration improvements of OMPS and compare the new data sets with previous versions to demonstrate what progress was achieved. While the new reprocessing is described in considerable detail, and its resultant improvements in quality of the SDRs are demonstrated convincingly, aspects of LT stability are barely mentioned. The authors should at least explain, how they intend to check for example the photometric stability in the future. This seems to be particularly important in the light of the non-negligible sensor degradation for SNPP.

Apart from this question I have several minor comments, which I list in the following.

Line 102: Explain abbreviation "ADL"

Line 127: The abbreviation "LT" should be explained already in line 121.

Line 145: The abbreviation "OMPS" was already explained in line 41.

Table 1: "250km by 250km" instead of "250km by 250k"

Equation (1): Why is there an apostrophe in the denominator?

Lines 231 and 232: The sensor-change cancels only through the ratio in the absence of non-linearities. The authors should at least mention this implicit assumption and give reasons why they think it is valid.

Table 2: τ_jl is explained twice.

Line 252: Explain the expression "observational smear". It appears in a sentence that extends over 13 lines. This whole paragraph should get a clearer structure, e. g. using separate lines to explain each variable.

Lines 264 - 266: I am not sure that one can assume the residual errors to be negligible, just because the calibration coefficients met the requirements before launch. I suggest to give here at least some actual values as examples of the requirements or, even better, to provide a link to the documentation of the pre-launch tests.

Figure 2: The writing is too small and therefore hard to read.

Line 330: I suggest to delete "thermal". "Thermal temperature" is a pleonasm.

Line 399: Explain the abbreviation "TC".

Line 556 and 557: This sentence is a bit difficult to understand. I suggest to make clearer what kind of variation the authors have in mind here.

Lines 576 - 581: I do not quite understand this - a wavelength shift should cause a systematic error. This error should be a certain fraction of the radiance. Why is then the relative difference at 253.51 nm particularly high?

Line 594 - 599: It is not clear whether the authors include in their numbers the random scatter or only the systematic component of the differences. Why does 292.41 nm have -1.0% and 301.85 nm -0.5%?

Line 608: I do not understand the "therefore" here.

Line 758: What feature in Fig. 12?

Figure 12: In the legend "radiance difference" instead of "radiance".

Line 806: The improved agreement is hard to see in the figure.

Line 817: Rather 0.001 than 0.0001 according to the figure.

Line 940 - 942: When will the future reprocessing probably happen?

Line 984: empty

Reference [48] is never mentioned in the text.

Author Response

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Reviewer 2 Report

Comments for author File: Comments.pdf

Author Response

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Reviewer 3 Report

The authors have produced a useful article that definitely warrants reporting. I support the general results and approach taken by them. However, I have a few edits, comments and questions that I would like the authors to clarify. Barring these minor issues, this manuscript is almost there for publication.

Suggestions:

1. The term LT is not clear  Please expand Long Term in the title and abbreviate in the text of the manuscript

2. In line 121, LT is given in abbreviation and in line 126 the expansion. Please provide the abbreviation meaning at the first instance. This is a long paper and so please check usage of your other abbreviations.

3. Lines 33-34 is confusing. Just give the overall improvement and one metric.

4. Lines 47-48 you mention about Limb but no good reference. There is a neat paper that gives the calibration and sensor performance for the same. G Jaross et al in AGU journal. Please give reference to that, interested readers can go there.

5. Lines 99-100 this paper focusses on SNPP then why mention NOAA 20. There is no use of NOAA 20 as you are not comparing anything with that sensor. Suggest deleting this.

6. Line 159 E capitals in Earth 

7. Provide R-square for Figure 5a

8. Figure 6 and 9 in particular and other figures past 6 are very tedious to read. Font and text in the plots need to be improved. Hard to read. 

9. Reading the entire paper and in particular Lines 922-929, I get the feeling that forward  processing of v2 is also bound to have inconsistencies. So are you going to update LUTs regularly. If so How? is it going to be a stepped LUT changes over time, weighted LUTs with interpolation between time periods. It is quite clear that static LUTs aren't going to keep up with the radiometric fidelity. Please explain.

 

 

 

Author Response

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