the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
| 10 Mar 2026
Observation operator and detection limits for MODIS and VIIRS Fire Radiative Power products
Abstract. We analyze the MODIS and VIIRS active-fire Fire Radiative Power (FRP) products and suggest an approximation for the FRP detection limit as a linear function of a pixel area and develop analytical observation operators for both pixel-level and gridded FRP products. We have shown that the collection-6.1 of MODIS has the FRP detection limit at 3.7 MW in case of a nadir retrieval at a clear-sky night. For a daytime sideview, it reaches as high as 40 MW. For VIIRS, the smallest fire reliably detected at night is 0.5 MW. Application of the developed operators for the cross-mapping the MODIS and VIIRS datasets at the pixel/granule level confirmed their consistency. Applying the grid-level operators alongside satellite overpass and weather data, we generated global maps of fire detection probabilities, revealing regional variations. As a global average, probability of detection of powerful fires is 78 % for MODIS (88 % for VIIRS). Variations between regions are large: in some equatorial areas this probability is less than 30 % for MODIS (40% for VIIRS).
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Status: final response (author comments only)
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RC1: 'Comment on egusphere-2026-89', Anonymous Referee #1, 15 May 2026
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AC1: 'Reply on RC1', Mikhail Sofiev, 17 May 2026
Thank you for the comments and evaluation !
In the revised paper version, we shall explain the symmetric OOp application in more details and also reduce the pixel-size section to make it easier to read.
Mikhail Sofiev
Citation: https://doi.org/10.5194/egusphere-2026-89-AC1
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AC1: 'Reply on RC1', Mikhail Sofiev, 17 May 2026
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RC2: 'Comment on egusphere-2026-89', Anonymous Referee #2, 26 Jul 2026
Please find my detailed review comments and suggestions in the attached PDF file.
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AC2: 'Reply on RC2', Mikhail Sofiev, 24 Aug 2026
Dear Reviewer,
Thank you very much for the detailed comments! We shall respond to each of them in details while preparing the revised version of the paper. Short answers are provided below
- regarding the aerosol attenuation of the FRP signal, we shall extend the discussion; however, we would like to point out that the 4-um AOD is an adequate parameter for this correction because the MODIS Collection 6 and 6.1 algorithm, albeit using a range wavelengths for processing, exclusively relies on the 4-um channel to calculate the FRP absolute value (Giglio et al, 2016, Eq. 16). Other bands (same paper, Table 1) serve for non-fire rejections and active fire detection. As pointed out in the paper, AOD those wavelengths can have their impact only for acceptance-rejection of near-edge fire detection. The revised paper includes more detailed discussion of the subject.
- description of methodology will be expanded
- discussion on sensitivity of the omission error estimate to the procedure of its calculation will be turned from a qualitative text to a more quantitative presentation of the conducted sensitivity studies
- we shall also expand the comparison with SEVIRI and VIIRS and make it more quantitative. However, we would like to point out that explicit estimates of the FRP detection limit of these satellites are all but absent - this was the main motivation for developing our OOp and writing this paper.
- minor corrections will all be taken into account in the revised paper
Thank you for your comments!
With best wishes
Mikhail and Rostislav
Citation: https://doi.org/10.5194/egusphere-2026-89-AC2 -
AC1: 'Reply on RC1', Mikhail Sofiev, 17 May 2026
Thank you for the comments and evaluation !
In the revised paper version, we shall explain the symmetric OOp application in more details and also reduce the pixel-size section to make it easier to read.
Mikhail Sofiev
Citation: https://doi.org/10.5194/egusphere-2026-89-AC1
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AC2: 'Reply on RC2', Mikhail Sofiev, 24 Aug 2026
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This paper analyzes the quantity of wildfires missed by earth-observing satellites. Â It particularly compares the data from the MODIS and VIIRS systems. Â The paper draws the interesting conclusion that the fraction of missed fires may be higher than previously reported.
The best aspect of the paper is the analysis that leads to the comparison of the two systems. Â It could be improve by a bit more explanation of how the "symmetric OOp application" (line 289) is performed.
The weakest aspect is the pixel size analysis, which could be reduced and summarized for readability.
Overall, this is a very good paper that is basically ready for publication.