Seasonal variation of CCN concentrations and aerosol activation properties in boreal forest

Show full item record



Permalink

http://hdl.handle.net/10138/332628

Citation

Sihto , S-L , Mikkilä , J , Vanhanen , J , Ehn , M , Liao , L , Lehtipalo , K , Aalto , P , Duplissy , J , Petäjä , T , Kerminen , V-M , Boy , M & Kulmala , M 2011 , ' Seasonal variation of CCN concentrations and aerosol activation properties in boreal forest ' , Atmospheric Chemistry and Physics , vol. 11 , no. 24 , pp. 13269-13285 . https://doi.org/10.5194/acp-11-13269-2011

Title: Seasonal variation of CCN concentrations and aerosol activation properties in boreal forest
Author: Sihto, Sanna-Liisa; Mikkilä, Jyri; Vanhanen, Joonas; Ehn, Mikael; Liao, Li; Lehtipalo, Katrianne; Aalto, Pasi; Duplissy, Jonathan; Petäjä, Tuukka; Kerminen, Veli-Matti; Boy, Michael; Kulmala, Markku
Contributor: University of Helsinki, Department of Physics
University of Helsinki, Department of Physics
University of Helsinki, Department of Physics
University of Helsinki, Department of Physics
University of Helsinki, Department of Physics
University of Helsinki, Department of Physics
University of Helsinki, Department of Physics
University of Helsinki, Department of Physics
University of Helsinki, Department of Physics
University of Helsinki, Department of Physics
University of Helsinki, Department of Physics
University of Helsinki, Department of Physics
Date: 2011
Language: eng
Number of pages: 17
Belongs to series: Atmospheric Chemistry and Physics
ISSN: 1680-7316
URI: http://hdl.handle.net/10138/332628
Abstract: As a part of EUCAARI activities, the annual cycle of cloud condensation nuclei (CCN) concentrations and critical diameter for cloud droplet activation as a function of supersaturation were measured using a CCN counter and a HTDMA (hygroscopicity tandem differential mobility analyzer) at SMEAR II station, Hyytiälä, Finland. The critical diameters for CCN activation were estimated from (i) the measured CCN concentration and particle size distribution data, and (ii) the hygroscopic growth factors by applying κ-Köhler theory, in both cases assuming an internally mixed aerosol. The critical diameters derived by these two methods were in good agreement with each other. The effect of new particle formation on the diurnal variation of CCN concentration and critical diameters was studied. New particle formation was observed to increase the CCN concentrations by 70–110%, depending on the supersaturation level. The average value for the κ-parameter determined from hygroscopicity measurements was κ = 0.18 and it predicted well the CCN activation in boreal forest conditions in Hyytiälä. The derived critical diameters and κ-parameter confirm earlier findings with other methods, that aerosol particles at CCN sizes in Hyytiälä are mostly organic, but contain also more hygrosopic, probably inorganic salts like ammonium sulphate, making the particles more CCN active than pure secondary organic aerosol.
Subject: CLOUD CONDENSATION NUCLEI
SECONDARY ORGANIC AEROSOL
HYGROSCOPIC PROPERTIES
PARTICLE FORMATION
SIZE DISTRIBUTION
SUBMICROMETER AEROSOL
ATMOSPHERIC AEROSOLS
SULFURIC-ACID
RAIN-FOREST
SMEAR-II
114 Physical sciences
Rights:


Files in this item

Total number of downloads: Loading...

Files Size Format View
acp_11_13269_2011.pdf 1.230Mb PDF View/Open

This item appears in the following Collection(s)

Show full item record