A European aerosol phenomenology – 6: scattering properties of atmospheric aerosol particles from 28 ACTRIS sites
(1)
,
(2)
,
(1)
,
(3)
,
(4)
,
(5)
,
(6, 7)
,
(8)
,
(9)
,
(8)
,
(10)
,
(11)
,
(5)
,
(12, 13)
,
(14)
,
(1)
,
(15)
,
(16)
,
(15)
,
(17)
,
,
(18)
,
,
(19)
,
,
,
(4)
,
(20, 21)
,
(20)
,
(22)
,
(6)
,
(7)
,
(17)
,
(6)
,
(2)
,
(9)
,
(20, 21)
,
(19)
,
(23)
,
,
(6)
,
(16, 12, 24)
,
(23)
,
(14)
,
(25)
,
,
(12, 24)
,
(23)
,
(22)
,
(2)
,
(26)
,
,
(14)
,
(27)
,
,
(6)
,
(15)
,
(8)
,
(3)
,
(6, 9, 18)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
Marcos Andrade
- Function : Author
- PersonId : 792450
- ORCID : 0000-0002-9736-493X
Nicolas Bukowiecki
- Function : Author
- PersonId : 792136
- ORCID : 0000-0002-2925-8553
Vincent Crenn
- Function : Author
- PersonId : 778072
- ORCID : 0000-0002-6563-8895
Kostas Eleftheriadis
- Function : Author
- PersonId : 784665
- ORCID : 0000-0003-2265-4905
Markus Fiebig
- Function : Author
- PersonId : 792451
- ORCID : 0000-0002-3380-3470
Harald Flentje
- Function : Author
Martin Gysel
- Function : Author
Andras Hoffer
- Function : Author
Adela Holubova Smejkalova
- Function : Author
Nikos Kalivitis
- Function : Author
- PersonId : 792135
- ORCID : 0000-0002-0005-7467
Markku Kulmala
- Function : Author
- PersonId : 763836
- ORCID : 0000-0003-3464-7825
- IdRef : 15928953X
Heikki Lihavainen
- Function : Author
- PersonId : 792452
- ORCID : 0000-0002-6135-4473
Hassan Lyamani
- Function : Author
- PersonId : 792453
- ORCID : 0000-0002-6386-1102
Angela Marinoni
- Function : Author
- PersonId : 757484
- ORCID : 0000-0002-6580-7126
Colin O’dowd
- Function : Author
Jean-Eudes Petit
- Function : Author
- PersonId : 735727
- IdHAL : jepetit
- ORCID : 0000-0003-1516-5927
- IdRef : 185077250
Sergio Rodríguez
- Function : Author
Jean Sciare
- Function : Author
- PersonId : 770356
- ORCID : 0000-0002-9908-6718
Peter Tunved
- Function : Author
Milan Vana
- Function : Author
Alfred Wiedensohler
- Function : Author
- PersonId : 777833
- ORCID : 0000-0001-8298-491X
Abstract
This paper presents the light-scattering properties of atmospheric aerosol particles measured over the past decade at 28 ACTRIS observatories, which are located mainly in Europe. The data include particle light scattering (σsp) and hemispheric backscattering (σbsp) coefficients, scattering Ångström exponent (SAE), backscatter fraction (BF) and asymmetry parameter (g). An increasing gradient of σsp is observed when moving from remote environments (arctic/mountain) to regional and to urban environments. At a regional level in Europe, σsp also increases when moving from Nordic and Baltic countries and from western Europe to central/eastern Europe, whereas no clear spatial gradient is observed for other station environments. The SAE does not show a clear gradient as a function of the placement of the station. However, a west-to-east-increasing gradient is observed for both regional and mountain placements, suggesting a lower fraction of fine-mode particle in western/south-western Europe compared to central and eastern Europe, where the fine-mode particles dominate the scattering. The g does not show any clear gradient by station placement or geographical location reflecting the complex relationship of this parameter with the physical properties of the aerosol particles. Both the station placement and the geographical location are important factors affecting the intra-annual variability. At mountain sites, higher σsp and SAE values are measured in the summer due to the enhanced boundary layer influence and/or new particle-formation episodes. Conversely, the lower horizontal and vertical dispersion during winter leads to higher σsp values at all low-altitude sites in central and eastern Europe compared to summer. These sites also show SAE maxima in the summer (with corresponding g minima). At all sites, both SAE and g show a strong variation with aerosol particle loading. The lowest values of g are always observed together with low σsp values, indicating a larger contribution from particles in the smaller accumulation mode. During periods of high σsp values, the variation of g is less pronounced, whereas the SAE increases or decreases, suggesting changes mostly in the coarse aerosol particle mode rather than in the fine mode. Statistically significant decreasing trends of σsp are observed at 5 out of the 13 stations included in the trend analyses. The total reductions of σsp are consistent with those reported for PM2.5 and PM10 mass concentrations over similar periods across Europe.
Domains
Environmental Sciences
Origin : Publication funded by an institution
Loading...