Measurements of optical properties of atmospheric aerosols in Northern Finland

International audience Three years of continuous measurements of aerosol optical properties and simultaneous aerosol number size distribution measurements at Pallas GAW station, a remote subarctic site in the northern border of the boreal forest zone, have been analysed. The scattering coefficient a...

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Bibliographic Details
Main Authors: Aaltonen, V., Lihavainen, H., Kerminen, V.-M., Komppula, M., Hatakka, J., Eneroth, K., Kulmala, M., Viisanen, Y.
Other Authors: Finnish Meteorological Institute (FMI), Department of Applied Environmental Science Stockholm (ITM), Stockholm University, Department of Physical Sciences Helsinki, Helsingin yliopisto = Helsingfors universitet = University of Helsinki
Format: Article in Journal/Newspaper
Language:English
Published: HAL CCSD 2006
Subjects:
[SDU.OCEAN]Sciences of the Universe [physics]/Ocean
Atmosphere
Kola Peninsula
kola peninsula
Northern Finland
Subarctic
Online Access:https://hal.science/hal-00295876
https://hal.science/hal-00295876/document
https://hal.science/hal-00295876/file/acp-6-1155-2006.pdf
Description
Summary:International audience Three years of continuous measurements of aerosol optical properties and simultaneous aerosol number size distribution measurements at Pallas GAW station, a remote subarctic site in the northern border of the boreal forest zone, have been analysed. The scattering coefficient at 550 nm varied from 0.2 to 94.4 Mm ?1 with an average of 7.1±8.6 Mm ?1 . Both the scattering and backscattering coefficients had a clear seasonal cycle with an autumn minimum and a 4?5 times higher summer maximum. The scattering was dominated by submicron aerosols and especially so during late summer and autumn. The Ångström exponent had a clear seasonal pattern with maximum values in late summer and minimum values during wintertime. The highest hemispheric backscattering fraction values were observed in autumn. To analyse the influence of air mass origin on the aerosol optical properties a trajectory climatology was applied to the Pallas aerosol data. The most polluted trajectory patterns represented air masses from the Kola Peninsula, Scandinavia and Russia as well as long-range transport from Britain and Eastern Europe. These air masses had the largest average scattering and backscattering coefficients for all seasons. Higher than average values of the Ångström exponent were also observed in connection with transport from these areas.

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