Complex refractive index and single scattering albedo of Icelandic dust in the shortwave part of the spectrum

Baldo, Clarissa; Formenti, Paola; Di Biagio, Claudia; Lu, Gongda; Song, Congbo; Cazaunau, Mathieu; Pangui, Edouard; Doussin, Jean-Francois; Dagsson-Waldhauserova, Pavla; Arnalds, Olafur; Beddows, David; MacKenzie, A. Robert; Shi, Zongbo

doi:https://doi.org/10.5194/acp-23-7975-2023

Articles | Volume 23, issue 14

https://doi.org/10.5194/acp-23-7975-2023

© Author(s) 2023. This work is distributed under
the Creative Commons Attribution 4.0 License.

https://doi.org/10.5194/acp-23-7975-2023

© Author(s) 2023. This work is distributed under
the Creative Commons Attribution 4.0 License.

Articles | Volume 23, issue 14

Research article

|

18 Jul 2023

Research article |

| 18 Jul 2023

Complex refractive index and single scattering albedo of Icelandic dust in the shortwave part of the spectrum

Clarissa Baldo, Paola Formenti, Claudia Di Biagio, Gongda Lu, Congbo Song, Mathieu Cazaunau, Edouard Pangui, Jean-Francois Doussin, Pavla Dagsson-Waldhauserova, Olafur Arnalds, David Beddows, A. Robert MacKenzie, and Zongbo Shi

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Final revised paper (published on 18 Jul 2023)
Supplement to the final revised paper
Preprint (discussion started on 10 Mar 2023)
Supplement to the preprint

Interactive discussion

Status: closed

RC1: 'Comment on egusphere-2023-276', Anonymous Referee #1, 20 Apr 2023

The comment was uploaded in the form of a supplement: https://egusphere.copernicus.org/preprints/2023/egusphere-2023-276/egusphere-2023-276-RC1-supplement.pdf

Citation: https://doi.org/10.5194/egusphere-2023-276-RC1
RC2: 'Comment on egusphere-2023-276', Anonymous Referee #2, 24 Apr 2023

General
The paper deals with a systematic laboratory study on the relationship between (a) the measured microphysical properties (size distribution) and spectral scattering and absorption coefficients and (b) the spectral single scattering albedo (SSA) and complex refractive index. The laboratory work is carefully and professionally performed by experienced scientists.
I have some minor remarks, only.
Introduction:
p2, line 45: Icelandic dust can reach several kilometres in altitude. Can you provide some numbers, 2km, 4 km, 8 km height. Some kind of a small summary. And also, how was it measured, ceilometer? aircraft? balloon? If dust at, e.g., 3 km height is observed, how can you be sure that this was Icelandic dust and not dust from other continents? So, I want to know a bit more about the range the Iceland dust can reach and potential horizontal transport scales.
Results
p11, line 302: I personally find these plots in Figure S2 very important for the study. It is always the question: Could the full size range be covered? And then these nice and important plots are at all in the supplementary.
Figure 7: I was completely lost… All symbols (left column) in the legend are in black, and references are given (to each black symbol). In the figure, the symbols then have colors. In the legend, we have many colored full circles (but no references!). The k values for the volcanic ash are 3-4 orders of magnitude lower than for Icelandic dust. So, ash is totally non absorbing? Confusing?
Final point:
Figure 8: This figure shows a nice comparison with other dusts from other major sources, but all measured by the same team!
I miss a bit a comparison with other findings, by other groups, from different field campaigns (maybe from different deserts and continents). I remember, e.g., these SAMUM campaigns. There was this paper of Mueller et al, JGR 2010 (2009JD12520) with refractive index values etc. I could imagine, there are several other studies showing SSA and refractive index properties.
Is it possible to have another figure or a table with different (independent) findings from different field studies… together with your findings?

Citation: https://doi.org/10.5194/egusphere-2023-276-RC2
AC1: 'Comment on egusphere-2023-276', Clarissa Baldo, 06 Jun 2023

The response to reviewers' comments is attached

Citation: https://doi.org/10.5194/egusphere-2023-276-AC1

Peer review completion

AR: Author's response | RR: Referee report | ED: Editor decision | EF: Editorial file upload

AR by Clarissa Baldo on behalf of the Authors (06 Jun 2023) Author's response Author's tracked changes Manuscript

ED: Publish as is (11 Jun 2023) by Allan Bertram

AR by Clarissa Baldo on behalf of the Authors (15 Jun 2023) Manuscript

Short summary

This paper presents new shortwave spectral complex refractive index and single scattering albedo data for Icelandic dust. Our results show that the imaginary part of the complex refractive index of Icelandic dust is at the upper end of the range of low-latitude dust. Furthermore, we observed that Icelandic dust is more absorbing towards the near-infrared, which we attribute to its high magnetite content. These findings are important for modeling dust aerosol radiative effects in the Arctic.