The regime of aerosol asymmetry parameter over Europe, the Mediterranean and the Middle East based on MODIS satellite data: evaluation against surface AERONET measurements

Korras-Carraca, M. B.; Hatzianastassiou, N.; Matsoukas, C.; Gkikas, A.; Papadimas, C. D.

doi:https://doi.org/10.5194/acp-15-13113-2015

Articles | Volume 15, issue 22

https://doi.org/10.5194/acp-15-13113-2015

© Author(s) 2015. This work is distributed under
the Creative Commons Attribution 3.0 License.

https://doi.org/10.5194/acp-15-13113-2015

© Author(s) 2015. This work is distributed under
the Creative Commons Attribution 3.0 License.

Articles | Volume 15, issue 22

Research article

|

26 Nov 2015

Research article |

| 26 Nov 2015

The regime of aerosol asymmetry parameter over Europe, the Mediterranean and the Middle East based on MODIS satellite data: evaluation against surface AERONET measurements

M. B. Korras-Carraca, N. Hatzianastassiou, C. Matsoukas, A. Gkikas, and C. D. Papadimas

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Final revised paper (published on 26 Nov 2015)
Preprint (discussion started on 05 Sep 2014)

Interactive discussion

Status: closed

AC: Author comment | RC: Referee comment | SC: Short comment | EC: Editor comment

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- Supplement

SC C6642: 'Comments on MODIS data use - calibration effects on trends and sensor differences', Andrew Sayer, 08 Sep 2014
- AC C11721: 'Response to A. M. Sayer', Nikos Hatzianastassiou, 31 Jan 2015
RC C9123: 'Review of "The regime of aerosol asymmetry parameter over Europe, Mediterranean and middle East based on MODIS satellite data: Evaluation against surface AERONET measurements" by M.B. Korras-Carraca and co-workers.', Anonymous Referee #1, 13 Nov 2014
- AC C11735: 'Response to Reviewer 1', Nikos Hatzianastassiou, 31 Jan 2015
  - AC C11742: 'supplement', Nikos Hatzianastassiou, 31 Jan 2015
RC C9203: 'Review of "The regime of aerosol asymmetry parameter over Europe, Mediterranean and middle East based on MODIS satellite data: Evaluation against surface AERONET measurements" by Korras-Carraca et al.', Anonymous Referee #2, 15 Nov 2014
- AC C11743: 'Response to Reviewer 2', Nikos Hatzianastassiou, 31 Jan 2015

Peer-review completion

AR: Author's response | RR: Referee report | ED: Editor decision

AR by Nikos Hatzianastassiou on behalf of the Authors (31 Jan 2015) Manuscript

ED: Referee Nomination & Report Request started (28 Feb 2015) by Athanasios Nenes

RR by Anonymous Referee #2 (07 Mar 2015)

RR by Anonymous Referee #1 (19 Mar 2015)

RR by Anonymous Referee #3 (26 May 2015)

RR by Anonymous Referee #3 (16 Jun 2015)

Suggestions for revision or reasons for rejection

General Comments
This paper examines the spatiotemporal variations of the aerosol asymmetry parameter (g) over North Africa, the Arabian peninsula and Europe using the latest available collection (C051) of MODIS-Terra and Aqua datasets during 2000-2010 and 2002-2010, respectively. The paper analyzes the g values at three wavelengths and compares the values over the different sub-regions in view of dominant aerosol types and seasonality. Furthermore, compares the g values from MODIS (ocean algorithm) with those from coastal AERONET sites. In general, the topic cannot be considered as innovative, since the main concept is the spatio-temporal evolution of g, but such studies are sparse in the literature and, from this point of view, the current manuscript has scientific importance and maybe helpful for scientists working on aerosol science. The manuscript is well organized and written and the results are discussed again the dominant aerosol types in each region. However, many statements are not clarified and some references are needed at specific parts of the text. The figures are of high quality, however, in Figs 7 and 8, there is an inconsistency in the spatial distribution maps (see details below). Overall, the manuscript can be accepted for publication in the journal after revision. Below there are specific comments that are expected to help authors in improving the manuscript.

Specific comments:
Line 61. References are needed at the end of this sentence.
Line 81. Authors may include some few references out of the Mediterranean basin, focusing on works over subtropical Atlantic, Persian Gulf and Arabian Sea.
Line 86. You may also cite the important article by Ginoux et al. 2012.
Line 101. “namely our study case”. This can be deleted.
Lines 198-109. Revise as “"with values increasing with particle size"

Lines 110-113. “The phase … intensity”. A reference is needed here.
Lines 147-150. Authors should clarify that these retrievals correspond to MODIS ocean algorithm.
Lines 161-162. Revise as “reliable cloud-screened and quality assured Level 2 data.”
Lines 183-184. Here, a discussion of aerosol hygroscopicity with increase in size and enhancement of scattering processes that lead to higher g is needed with appropriate references.
Lines 191-192. Some references are needed for dust outflows over subtropical Atlantic and Arabian Sea.
Line 224. The reference Gkikas et al. 2014 is missing in the literature list.
Line 232. Correct as “in August”
Lines 234-235. The reference Prospero et al. (2002) is not so relevant for this sentence. Prospero et al. (2002) used mostly the AI values for the detection of the dust source regions. Especially for Deep Blue retrievals over Middle East and SW Asia, authors may see the Ginoux et al. (2012) paper. Focusing on the annual variability of dust over Middle East and SW Asia, authors may see the papers by Rashki et al. (2012), Rashki et al. (2014).
Line 242. A reference is needed for the MODIS Deep Blue AE data.
Line 248. “from June to September”. Shamal wind is also active in spring (March-May). You may see Najafi et al. (2013), Rezazadeh et al. (2013) and references therein.
Line 258. The reference Gkikas et al. 2013 is missing in the literature list.
Lines 258-261. This annual pattern has to be explained by the seasonal (summer) agricultural biomass burning in Ukraine (see Barnaba et al., 2011; Chubarova et al., 2012).
Lines 290-291. Revise as “"Further details and an overall picture is given in the section ...”
Line 341. “…by fine and coarse aerosols”. Here, you may be more specific by writing that the coarse-mode dust particles have lower spectral dependence of g compared to anthropogenic and biomass-burning aerosols.
Line 360. Replace “changes” as “trends”
Line 373. Correct as “than”
Lines 430-431. Relative differences as high as 30-40% are detected over large parts of the Atlantic Ocean, which are not in accordance with the discussions here.
Lines 456-457. Which AERONET values did you take for the correlations, the daily-mean or an hourly value close to MODIS overpass? This should be clarified in the manuscript.
Line 520-521. This sentence needs revision.
Figure 7. How you can have correlation between AE and g at northern latitudes where AE values are absent according to Fig. 7a?
Figure 8. How can we have values of correlation coefficient, biases and trends at northern latitudes where both Figs 7a and 8a do not contain values?

References:
Barnaba, F., F. Angelini, G. Curci, and G. P. Gobbi (2011), An important fingerprint of wildfires on the European aerosol load, Atmos. Chem. Phys., 11, 10,487–10,501.
Chubarova, N., Y. Nezval’, I. Sviridenkov, A. Smirnov, and I. Slutsker (2012), Smoke aerosol and its radiative effects during extreme fire event over central Russia in summer 2010, Atmos. Meas. Tech., 5, 557–568.
Ginoux P, Prospero JM, Gill TE, Hsu CN, Zhao M (2012) Global-scale attribution of anthropogenic and natural dust sources and their emission rates based on MODIS Deep Blue aerosol products. Rev Geophys 50: RG3005. doi:10.1029/2012RG000388
Najafi MS, Khoshakhllagh F, Zamanzadeh SM, Shirazi MH, Samadi M, Hajikhani S (2013) Characteristics of TSP Loads during the Middle East Springtime Dust Storm (MESDS) in Western Iran. Arab J Geosci (in press), doi: 10.1007/s12517-013-1086-z.
Rashki A, Kaskaoutis DG, Rautenbach CJW, Eriksson PG, Qiang M, Gupta P (2012) Dust storms and their horizontal dust loading in the Sistan region, Iran. Aeolian Res 5: 51–62.
A. Rashki, D.G. Kaskaoutis, C.J. de W. Rautenbach, C. Flamant, F. Abdi Vishkaee, 2014. Spatio-temporal variability of dust aerosols over the Sistan region in Iran based on satellite observations. Natural Hazards, doi: 10.1007/s11069-013-0927-0
Rezazadeh M, Irannejad P, Shao Y, (2013) Climatology of the Middle East dust events. Aeol Res 10: 103-109.

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ED: Reconsider after major revisions (28 Jun 2015) by Athanasios Nenes

AR by Nikos Hatzianastassiou on behalf of the Authors (11 Sep 2015) Manuscript

ED: Referee Nomination & Report Request started (22 Sep 2015) by Athanasios Nenes

RR by Anonymous Referee #2 (30 Sep 2015)

RR by Dimitris Kaskaoutis (01 Oct 2015)

Suggestions for revision or reasons for rejection

In the abstract, authors should note that the MODIS retrievals and total analysis corresponds to the oceanic areas only comprising the mentioned regions.
Lines 120-121. This sentence may be omitted as redundant of the above (lines 110-112).
Lines 125-129. This paragraph may be omitted, since the detailed description is given in the very next section. In case you want to maintain it, I suggest shortening it.
Line 151. Is this the 870 nm wavelength or the 860 as referred in line 164? Please, check once again and correct. It should be also nice to add one sentence explaining why you finally choose these three wavelengths for g retrievals, leaving out the 550 and infrared ones.
Line 158. Correct as "fine-mode"
Lines 219-224. These lines may be omitted since the first sentence constitutes a repetition of discussions given in section 2 and the rest of the text refers to g and AOD diurnal variations, which are not presented here and, furthermore, they have not strong association between them. I think that discussing the AOD diurnal variation in such a brief way it is not of any advantage for the paper.
Lines 294-296. The lower g values in spring and summer cannot be associated with the enhanced presence of dust. Dust, as stated in the rest of the manuscript tends to increase the g values. Please, correct...
Line 385. One of the terms "greater" or "larger" should be removed.
Line 441. Delete "retrieval".
Lines 468-469. This sentence needs revision. The syntax "... data for all but winter months," seems rather problematic.
Lines 516-520. This has already been discussed in detail in section 2.2. Authors should shorten this part avoiding repetitions.
Line 604. Delete the double dot here.

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ED: Publish subject to technical corrections (01 Oct 2015) by Athanasios Nenes

AR by Nikos Hatzianastassiou on behalf of the Authors (09 Oct 2015) Author's response Manuscript