Transport and Variability of Tropospheric Ozone over Oceania and Southern Pacific during the 2019–20 Australian Bushfires
, Fabrice Jégou 2, Hélène Vérèmes 1, Sergey Khaykin 3, Gisèle Krysztofiak 2, Thierry Portafaix 1, Valentin Duflot 1, Alexandre Baron 1, Gwenaël Berthet 2, Corinna Kloss 2, Guillaume Payen 4, Philippe Keckhut 3, Pierre-François Coheur 5, Cathy Clerbaux 3,5, Dan Smale 6, John Robinson 6, Richard Querel 6 and Penny Smale 6Round 1
Reviewer 1 Report
This is an excellent paper and one of the best papers I have read in a while and I think it will be of high interest to the scientific community. It is very rigorous, thorough, well-written with excellent literature review, excellent figures, and extensive use of many data sets in the analysis.
I don’t have any major comments. My only minor suggestion would be to discuss the spectrum of transport processes a bit more (from sea breezes along the coast, terrain-flows, high-pressure systems to the vertical infusion of pollution high up through intense fire plumes).
Only other minor suggestion is to mention that fully coupled WRF-Chem type simulations which include fire pollution sources would be useful in the future (difficult to do of course!) to compare validate against the many different satellite and in situ observations data sets.
Minor comments:
Typo in the abstract after total columns: “The highest values of Aerosols Optical Depth (AOD) and carbon monoxide total columns ( are observed over Southern and Central Australia.”
Line 60: “photochemically compound” should be “photochemical compounds” I think
Line 185: I believe that Lauder, Australia should be noted (rather than just Lauder).
Similarly, on 2015 Samoa is introduced. I think it would be better to introduce all the sites and make sure it is clear where each one is located on one of the figures (sites are introduced without referencing on a map currently).
Author Response
Dear editor and reviewers,
First all, we thank you for attention that you will grant to our manuscript: « Transport and variability of tropospheric ozone over Oceania and Southern Pacific during the 2019-20 Australia bushfires». As a contact author, I confirm that all co-author concur with the submission of this manuscript. Please see the attachment
Author Response File: 
Author Response.pdf
Reviewer 2 Report
This paper describes the transport and the variability of ozone over Oceania and Southern Pacific caused by the huge Australian bushfires of the Austral summer 2019-2020. To do this, the authors exploited a series of atmospheric data sets from satellite, ground-based and sonde instruments. The species discussed more particularly are aerosols, CO, and obviously ozone, while fire counts from MODIS have also been used for the discussion. Using those data sets, they illustrated how the large fires that took place in Australia have affected the atmospheric composition over long distances due to the transport of air masses and how the gases emitted during those events led to enhanced production of ozone in the troposphere, but also in the stratosphere during pyro-convection events.
The paper reads well, the discussion is easy to follow, and the context is well introduced with a larger number of references to other works. The work, although without any real new breakthrough, documents well the event and the collection of the different data sets makes it convincing. This work deserves to be published and I have only some minor comments to take into account beforehand.
Minor comments :
Line 199 : please specify how many degrees of freedom are obtained from the retrievals in the troposphere for both O3 and CO.
Line 344 : What about the orbit of Aqua ? Only the one of Terra is explained. Are the two satellites used ?
Fig 5b : Even if it’s not statistically significant, it is striking to see a systematic reduction of the stratospheric O3 after 12-01, simultaneously to the increase of the tropospheric O3. Could you elaborate a bit more on this? Is there a temporal evolution of the tropopause height, which could explain this? Are the two patterns related somehow?
Technical comments :
Line 32 : remove the single bracket
Line 139 : add « of » in « in view of the potential »
Line 178: (The dataset…) to be removed (repetition of line 169).
Line 495 : add « period » after 2020
Fig 5a : please explicit in the caption that the black curves correspond to total ozone (and not CO)
Line 525: “when a non biomass plume” is unclear. Is there a plume not related to biomass burning passing over Lauder or is there simply no plume. Please rephrase.
Line 552: “CO” is missing in “have clearly shown that CO is an ozone precursor »
Figure 7 : There is an issue with the caption. Remove « Figure 3 » and add missing words.
Line 630 : « lift » instead of « loft »
Lines 672-680 : Please rephrase to avoid repetitions.
Lines 697-701 : Sentences incomplete. Please correct them.
Lines 730-731 : repetition
Line 775 : Replace « Understanding » by « To understand »
Author Response
Dear editor and reviewers,
First all, we thank you for attention that you will grant to our manuscript: « Transport and variability of tropospheric ozone over Oceania and Southern Pacific during the 2019-20 Australia bushfires». As a contact author, I confirm that all co-author concur with the submission of this manuscript. Please see the attachment.
Sincerely,
Dr. Nelson Bègue
Author Response File: Author Response.pdf
