 |
| Titel |
On the interpretation of the loading correction of the aethalometer |
| VerfasserIn |
A. Virkkula, X. Chi, A. Ding, Y. Shen, W. Nie, X. Qi, L. Zheng, X. Huang, Y. Xie, J. Wang, T. Petäjä, M. Kulmala  |
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| ISSN |
1867-1381
|
| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Measurement Techniques ; 8, no. 10 ; Nr. 8, no. 10 (2015-10-21), S.4415-4427 |
| Datensatznummer |
250116646
|
| Publikation (Nr.) |
 copernicus.org/amt-8-4415-2015.pdf |
|
|
|
|
|
| Zusammenfassung |
| Aerosol optical properties were measured with a seven-wavelength
aethalometer and a three-wavelength nephelometer at the suburban site SORPES
in Nanjing, China, in September 2013–January 2015. The aethalometer
compensation parameter k, calculated with the Virkkula et al. (2007) method
depended on the backscatter fraction, measured with an independent method,
the integrating nephelometer. At λ = 660 nm the daily averaged
compensation parameter k ≈ 0.0017 ± 0.0002 and
0.0042 ± 0.0013 when backscatter fraction at λ = 635 nm was
in the ranges of 0.100 ± 0.005 and 0.160 ± 0.005, respectively.
Also, the wavelength dependency of the compensation parameter depended on the
backscatter fraction: when b(λ = 525 nm) was less than
approximately 0.13 the compensation parameter decreased with wavelength and
at larger b it increased with wavelength. This dependency has not been
considered in any of the algorithms that are currently used for processing
aethalometer data. The compensation parameter also depended on the
single-scattering albedo ω0 so that k decreased with increasing
ω0. For the green light (λ = 520 nm) in the ω0
range 0.870 ± 0.005, the average (± standard deviation) k ≈ 0.0047 ± 0.006 and in the ω0 range 0.960 ± 0.005, k
≈ 0.0028 ± 0.0007. This difference was larger for the
near-infrared light (λ = 880 nm): in the ω0 range
0.860 ± 0.005, k ≈ 0.0055 ± 0.0023 and in the
ω0 range 0.960 ± 0.005, k ≈ 0.0019 ± 0.0011.
The negative dependence of k on ω0 was also shown with a simple
theoretical analysis. |
| |
|
| Teil von |
|
|
|
|
|
|
|
|