the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Exceptional high AOD over Svalbard in Summer 2019: A multi-instrumental approach
Abstract. In the summer of 2019, the Arctic region registered exceptionally high aerosol optical depth (AOD) values over Svalbard, linked to intense biomass burning and volcanic activity across the Northern Hemisphere. This study presents a comprehensive, multi-instrumental analysis of the aerosol conditions in and around Ny-Ålesund (Spitsbergen, Norway), combining data from ground-based sun-photometry, in-situ observations, active remote sensing (ground-based and on satellite), and atmospheric dispersion modeling. Despite high AOD was observed during all the period, three different aerosol events are identified in the atmospheric column (6–10 July, 25–28 July, and 6–17 August). In contrast, in-situ surface stations only recorded significant aerosol load during 5–9 July, 30 August, and 12 September, suggesting that most of the aerosol particles remained above the boundary layer. Lidar and photometric observations revealed the presence of spherical, weakly absorbing Accumulation-mode particles (0.1–0.2 µm) in both the troposphere and stratosphere, with persistent layers extending above 10 km. Simulations carried out with FLEXPART correlate well with the measurements, attributing the observed aerosol events to multiple sources, including Siberian and North American wildfires, the Raikoke (Russia) volcanic eruption, and anthropogenic pollution. Overall, the aerosol radiative impact during this long-lasting event was substantial, with a mean reduction in direct solar radiation of approximately -74 W / m2 during July and August. This work shows how the use of dispersion modelling together with multiple observation sources allows to achieve a more complete description of the atmospheric aerosol events and contributes to a better understanding of the overall picture.
Competing interests: At least one of the (co-)authors is a member of the editorial board of Atmospheric Chemistry and Physics.
Publisher's note: Copernicus Publications remains neutral with regard to jurisdictional claims made in the text, published maps, institutional affiliations, or any other geographical representation in this paper. While Copernicus Publications makes every effort to include appropriate place names, the final responsibility lies with the authors. Views expressed in the text are those of the authors and do not necessarily reflect the views of the publisher.- Preprint
(14060 KB) - Metadata XML
-
Supplement
(2068 KB) - BibTeX
- EndNote
Status: open (until 27 Oct 2025)
- RC1: 'Comment on egusphere-2025-3423', Anonymous Referee #2, 18 Sep 2025 reply
Viewed
HTML | XML | Total | Supplement | BibTeX | EndNote | |
---|---|---|---|---|---|---|
1,679 | 32 | 8 | 1,719 | 10 | 8 | 5 |
- HTML: 1,679
- PDF: 32
- XML: 8
- Total: 1,719
- Supplement: 10
- BibTeX: 8
- EndNote: 5
Viewed (geographical distribution)
Country | # | Views | % |
---|
Total: | 0 |
HTML: | 0 |
PDF: | 0 |
XML: | 0 |
- 1
The paper "Exceptional high AOD over Svalbard in Summer 2019: A multi-instrumental approach" by Herrero-Anta et al. is a thorough study of an episode of enhanced aerosol at Svalbard during summer 2019. It combines observations of several instruments to identify aerosol characteristics. Further, modeling with FLEXPART is used to identify the different sources of the aerosol.
Overall, the paper presents a comprehensive, logically structured study, it is well written, and is of interest to the broad readership of ACP.
The paper is therefore recommended for publication in ACP after addressing my minor comments as detailed below.
My main comment is that in some places discussion of some features in the data is missing.
SPECIFIC (MINOR) COMMENTS:
(1) Fig.2: Please comment!
Why is there a peak of AOD with strong standard deviation in the reference record between 1 and 15 July?
Is this a repetitive event each year?
Or is this peak attributable to a specific event? If yes, which?
(2) Fig.4: For the S1 event, beta_sca is only enhanced at GAL, but not at ZEP, while beta_abs is enhanced at both sites.
Do you have any explanation for this?
(3) l.301-311, about Fig.5: ZEP discussion is missing!
Here you should also comment about the PNSD at ZEP, which does not show a clear bimodal structure during the surface events, and the distributions peak at sizes between Aitken and Accumulation mode.
(4) l.324-325: What about the other layers seen by KARL?
There is a more intense layer at 13km that is not seen by CALIOP. Why?
Is this an issue of the CALIOP sensitivity?
(5) l.447-449: Thin cirrus clouds are hard to detect by ground based and space based instrumentation. Could thin (subvisible) cirrus clouds also contribute to negative values of delta-DNI?
TECHNICAL COMMENTS:
(1) l.28: levels.Lisok -> levels. Lisok
(2) l.52: Siberian wildfires -> smoke of the Siberian wildfires
(3) Table 1: abbreviations of several parameters (e.g., DNI, DIF) are only given later in the text. This should be mentioned in the table caption.
(4) l.148: can be also be -> can also be
(5) l.161:
to Reference Upper-Air Network (GRUAN).
->
to the Global Climate Observing System (GCOS) Reference Upper-Air Network (GRUAN).
(6) l.171: from zero to the unit, being small -> from zero to unity, with small
(7) caption of Fig.2, l.2-3: Sentence "Long-term daily means ..." can be deleted because same info is given at the end of the caption.
(8) caption of Fig.2, l.5: with errors bar -> with error bars
(9) l.253: one maxima -> one maximum
(10), (11) l.254: main maxima -> main maximum
second maxima -> second maximum
(12) l.259: This longer radii -> These larger radii
(13) p.11, last line: longer -> larger
(14) l.277: next mean values: -> following mean values:
(15) Table 3 and text on p.13:
Here you use B_abs and B_sca instead of beta_abs and beta_sca.
Please use consistent notation throughout!
(16) caption of Fig.5: the are only -> there are only
(17) l.303: With respect GAL observations -> Regarding GAL observations
(18) l.331: is shown -> are shown
(19) l.361: row)is -> row) is
(20) Caption of Fig.10: red line -> magenta line
(21) Caption of Fig.11: With respect the sources -> With respect to the sources
(22) Caption of Fig.12: with respect the reference -> with respect to the reference
(23) l.495: Ship born -> Ship borne
(24) l.503: under reques to the authors -> under request to the authors.