Dear Authors,

I have not received your response to the report of the 3rd reviewer. Could you please address the reviewer's concerns:

This manuscript approaches a very interesting topic, increasing fire frequency in high latitude peatlands and the influence of peat fire atmospheric emissions on radiative forcing and climate change through deposition on high albedo surfaces such as snow and ice. However, I believe that the manuscript takes a totally misguided approach by focusing on BC emissions because peat fires burn almost exclusively with smoldering combustion that does not emit BC but large quantities of OC (as shown in the cited emission factors of Agaki et al., 2011 with OC emission factors being a factor of 30 larger than those of BC). Therefore, it is general knowledge that aerosol light absorption by smoke from peat fires is largely caused by BrC, not by BC. Therefore, I suggest that the authors refocus their manuscript on BrC and examine its radiative forcing and compare it to that of BC. Below, I’ve given a number of relevant publications to help the authors get started with this. In addition, the modification of the spectral reflectivity of snow through the deposition of peat combustion smoke has recently been discussed (Beres and Moosmuller, 2018).

REFERENCES
Akagi, S. K., Yokelson, R. J., Wiedinmyer, C., Alvarado, M. J., Reid, J. S., Karl, T., Crounse, J. D. and Wennberg, P. O.: Emission factors for open and domestic biomass burning for use 
in atmospheric models, Atmos. Chem. Phys., 11(9), 4039–407doi:10.5194/acp-11- 4039-2011, 2011.


Beres, N. D. and H. Moosmüller (2018). Apparatus for Dry Deposition of Aerosols on Snow. Atmos. Meas. Tech. Discuss., doi.org/10.5194/amt-2018-194, Atmos. Meas. Tech., in review.

Black, R. R., J. Aurell, A. Holder, I. J. George, B. K. Gullett, M. D. Hays, C. D. Geron, and D. Tabor (2016), Characterization of Gas and Particle Emissions from Laboratory Burns of Peat, Atmos. Environ., 132, 49-57.

Bhattarai, C., V. Samburova, D. Sengupta, M. Iaukea-Lum, A. C. Watts, H. Moosmüller, and A. Y. Khlystov (2018), Physical and Chemical Characterization of Aerosol in Fresh and Aged Emissions from Open Combustion of Biomass Fuels, Aerosol Sci. Tech., DOI: 10.1080/02786826.2018.1498585.

Chakrabarty, R. K., H. Moosmüller, L.-W. A. Chen, K. Lewis, W. P. Arnott, C. Mazzoleni, M. K. Dubey, C. E. Wold, W. M. Hao, and S. M. Kreidenweis (2010), Brown Carbon in Tar Balls from Smoldering Biomass Combustion, Atmos. Chem. Phys., 10, 6363-6370.

Chakrabarty, R. K., M. Gyawali, R. L. N. Yatavelli, A. Pandey, A. C. Watts, J. Knue, L. W. A. Chen, R. R. Pattison, A. Tsibart, V. Samburova, and H. Moosmüller (2016), Brown Carbon Aerosols from Burning of Boreal Peatlands: Microphysical Properties, Emission Factors, and Implications for Direct Radiative Forcing, Atmos. Chem. Phys., 16(5), 3033-3040.

Lin, P., P. K. Aiona, Y. Li, M. Shiraiwa, J. Laskin, S. A. Nizkorodov, and A. Laskin (2016), Molecular Characterization of Brown Carbon in Biomass Burning Aerosol Particles, Environ. Sci. Technol., 50(21), 11815-11824.

Samburova, V., J. Connolly, M. Gyawali, R. L. N. Yatavelli, A. C. Watts, R. K. Chakrabarty, B. Zielinska, H. Moosmüller, and A. Khlystov (2016), Polycyclic Aromatic Hydrocarbons in Biomass-Burning Emissions and Their Contribution to Light Absorption and Aerosol Toxicity, Sci. Total Environ., 568, 391-401.

Sengupta, D., V. Samburova, C. Bhattarai, E. Kirillova, L. Mazzoleni, M. Iaukea-Lum, A. Watts, H. Moosmüller, and A. Khlystov (2018), Light Absorption by Polar and Non-Polar Aerosol Compounds from Laboratory Biomass Combustion, Atmos. Chem. Phys., 18(15), 10849-10867.

Sumlin, B. J., Y. W. Heinson, N. Shetty, A. Pandey, R. S. Pattison, S. Baker, W. M. Hao, and R. K. Chakrabarty (2018), UV-Vis-IR Spectral Complex Refractive Indices and Optical Properties of Brown Carbon Aerosol from Biomass Burning, Journal of Quantitative Spectroscopy and Radiative Transfer, 206, 392-398.

- I agree with the reviewer, and think that the last three sentences of the abstract are too speculative and misleading, please remove them: “However, the very large fraction of the emissions deposited on the Greenland Ice Sheet makes these fires very efficient climate forcers on a per unit emission basis. If the expected future warming of the Arctic produces more severe fires in Greenland, this could indeed cause albedo changes and thus contribute to accelerated melting of the Greenland Ice Sheet. The fires burning in 2017 may be a harbinger of such future events.”

This is a local effect, and saying that they are very efficient climate forcers is misleading even if these fires become two orders of magnitude larger.

Maybe something along these lines is more appropriate:
However, the very large fraction of the emissions deposited on the Greenland Ice Sheet from these fires could contribute to accelerated melting of the Greenland Ice Sheet if these fires become several (1-2??) orders of magnitude larger under future climate.

Please address this issue in the conclusion too.


- In section 4.1 please use “to evaluate” rather than “to validate”.

- L938. There are two “on” please correct that.