the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Impact of Landes forest fires on air quality in France during the summer 2022
Laurent Menut
Arineh Cholakian
Guillaume Siour
Remy Lapere
Romain Pennel
Sylvain Mailler
Bertrand Bessagnet
Abstract. The atypical huge forest fires observed in France during the summer of 2022 are modelled using the CHIMERE model. Scenario simulations are performed without and with these fires to quantify the impact of these extra emissions on air quality thresholds exceedances. Additional processes are added in the model to better simulate fire emissions and then have more realistic simulations. The fires influence the characteristics of the surface by destroying the vegetation and creating new erodible surfaces. This increases the mineral dust emissions, but also reduces the Leaf Area Index, then decreases the biogenic emissions and the dry deposition of gases such as ozone. Results show that the fires induce numerous increases in surface ozone and Particulate Matter concentrations close to the sources but also in downwind remote sites such as the Paris area. During the period of the most intense fires in July, the impact of concentrations is mainly due to emissions themselves, when later, in August, ozone and PM concentrations continue to increase but this time due to changes in the burnt surfaces.
Laurent Menut et al.
Status: final response (author comments only)
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RC1: 'Comment on egusphere-2023-421', Anonymous Referee #1, 16 Apr 2023
Review of Menut et al. “Impact of Landes forest fires on air quality in France during the summer 2022”
Comments:
Menut et al. simulate the air quality impacts during a forest fire episode in France using the CHIMERE chemical transport model, also, uniquely, estimating the impacts of burned area on dust and biogenic emissions. Overall, this is a well-written, well-executed and focused case study with an interesting and fairly novel set of experiments. I have no major comments and only the following mostly editorial suggestions:
Title: change “..in France during the summer 2022” to “…in France during the 2022 summer”
L20: suggest omitting “mechanically”
L47: change “ii) do the biomass burning…” to “ii) does the biomass burning…”
L49: change “responsible of” to “responsible for”
L63: omit “well” from “well capture”
L72: please provide a brief description of Kaiser et al.’ (2012) based Global Fire Assimilation biomass burning product, mentioning that it is FRP-based, as distinct from the burned area, used to describe the 2022 fire episode
L72: please provide a brief description of the surface flux vertical distribution – are these FRP-based plume heights distributed as part of GFAS, or something else?
Figure 3: please point out the area of the Landes fires
L88: change “responsible of less dry deposition” to “responsible for less dry deposition”
L93: change “have in common to cover the period from 15 June to…” to “have a common period of 15 June to…”
L95: here and at L290, I wasn’t sure what was meant by ‘retroactions’. Would ‘interactions’ be suitable?
L152: change “transported toward west” to “transported westward”
L161: this sentence was a bit hard to understand, but I think would start with “The limitions of the simulations are probably…”
L164: can omit “results” from “model concentrations results”
L169: change “in altitude” to “at altitude”
L173: change “It is meaning..” to “It means…”
L216: change “Data are daily averaged” to “Data are averaged daily”
L224: change “Values are not very high as daily mean” to “Values are not as high as the daily mean”
L254: change “several atmospheric circulations” to “several synoptic events”?
L262: please describe briefly how the two thresholds were selected
L209: change from “The impact on mineral dust…” to “The impact of mineral dust…”?
L319: change “able to retrieve” to “able to capture”
L324: by “globally”, do you mean “regionally”?
Citation: https://doi.org/10.5194/egusphere-2023-421-RC1 -
RC2: 'Comment on egusphere-2023-421', Anonymous Referee #2, 25 Apr 2023
The study by Menut et al. explores the air pollution effects of intense wildfires that occur in the summer of 2022 in France, using an atmospheric chemical-transport model. A range of observational constraints are also utilized for the study, as well as sensitivity experiments with the model, which provide insights into the role of feedbacks via changes in the leaf area index and the dust emissions, along the direct effects of the wildfire emissions themselves.
The manuscript is well written and well within the scope of the journal, while it provides insights that will be useful for the evolving field of fire-land-atmosphere interactions. There is one key concern that I have, and a few more minor ones. If those are addressed, I believed the manuscript will be suitable for publication.
MAIN COMMENT:
While the first part of the manuscript studies both aerosols and ozone, the part that utilizes the sensitivity simulations to study feedbacks via processes impacted by fires focuses only on ozone. Why is that? Surely the dust perturbation should have implications for PM, and possibly the other simulations too. Please explain and expand the analysis/discussion if/as needed.
Also, via what mechanism does dust impact ozone in the model? Since chemicals and aerosols are not allowed to influence radiation/meteorology, it is probably implied that this is due to photolysis? This should be more clearly explained and discussed.
MINOR COMMENTS:
Abstract: The abstract should refer more to the studies results and less to its hypotheses.
Page 2, Line 28: What does “still” refer to?
Page 3, Line 66: “Several tens of chemical species, gas and aerosol, are modelled” – more detail needed. Also, how is photolysis treated?
Page 3, Line 72: Given that biomass burning emissions are central to the study, there should be a bit more insight into how CAMS emissions are derived.
Page 8, Line 140: correspond -> corresponds
Page 8, Lines 140-141: “The model overestimates the measurements but is composed of Primary Organic Matter (POM), signature of the biomass burning” – what does this mean? What does the second half of the sentence tell us?
Figure 5: Three panels are described in the caption, but four are shown. Also. The maps depict the differences, which needs to be mentioned in the caption.
Page 9, Line 160: “Finally, the impact of fires induces positive differences only” – perhaps add a second part to this sentence, to show why this is not entirely obvious (e.g. “…, indicating that the negative feedbacks from fire emissions do not outweigh the effects of direct emissions and positive feedbacks at any location.”)
Page 9, Lines 161-162: Why is this a drawback? (also, “lack” may not be the most suitable word to use here)
Page 10. Lines 173-174: Any ideas why?
Page 10, Lines 181-184: The EES and what it is should be explained more clearly.
Page 10, Lines 185-186: Yes, but there is also quite a large difference in PPM.
Line 227: others simulation -> other simulations
Figures 10 and 11: From these figures, the effect of fires seems to basically be minimal, if not negligible. Is this not the main conclusion of this section? Because there is plenty of analysis in this sub-section, but this bottom-line conclusion is not really coming across clearly.
Page 19, Line 305: “appears not” maybe should be “appears”?
Page 20, Line 324: “globally” can be a misleading use of word here.
Citation: https://doi.org/10.5194/egusphere-2023-421-RC2 -
AC1: 'Comment on egusphere-2023-421', Laurent Menut, 19 May 2023
The comment was uploaded in the form of a supplement: https://egusphere.copernicus.org/preprints/2023/egusphere-2023-421/egusphere-2023-421-AC1-supplement.pdf
Laurent Menut et al.
Laurent Menut et al.
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