Measurements of aerosol optical properties at the Station for - PowerPoint PPT Presentation

Measurements of aerosol optical properties at the Station for Measuring Ecosystem–Atmosphere Relations (SMEAR II), a boreal forest site in Finland A. VIRKKULA 1,2 , KRISTA LUOMA 2 , P. AALTO 2 , T. PETÄJÄ 2 , M. KULMALA 2 1 Finnish Meteorological Institute, FI-00560, Helsinki, Finland 2 Department of Physics, University of Helsinki, FI-00014, Helsinki, Finland

Where is it compared with the IASOA sites? SMEAR II, Hyytiälä Finland 61 ° 50’47”N, 24 ° 17’42”E, 181 m AMSL

SMEAR II-station (boreal forest, countryside) http://www.atm.helsinki.fi/SMEAR/

Aerosol cottage - size distributions - scattering - absorption - filter sampling - hygroscopicity - CCNC - volatility - ... For a detailed description of the site and all measurements see http://www.atm.helsinki.fi/SMEAR/

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In situ aerosol optics measurements at SMEAR II Scattering coefficient 2006-06-01 → Nephelometer, TSI 3563 Absorption coefficient 2004-12-08 → Magee Scientific, Aethalometer AE-31 RR, 3 λ Particle Soot Absorption Photometer (PSAP) 2011-10-12 – 2016-03-10 2012-11-01 → Thermo Electron CARUSSO / MAAP 5012 Extinction coefficient 2012-05-01 → Aerodyne Research CAPS PMex Monitor 6

Some old results α sp σ sp σ ap SMEAR II Trajectory statistics of scattering and absorption coefficients at λ = 550 nm and the Ångström exponent of scattering. Average value observed at SMEAR II from 13 October 2006 to 31 may 2009 when backtrajectories have crossed each grid cell. Virkkula et al.: Aerosol optical properties at SMEAR II, Hyytiälä, Finland, ACP, 2011 7

New results, Krista Luoma’s MSc thesis Decreasing trend Year Year 8

New results, Krista Luoma’s MSc thesis C ref from AE vs MAAP C ref Median Mean Std No ATN correction 3.15 3.23 1.60 Weingartner 3.36 3.46 1.65 Arnott 4.05 4.28 2.23 Iterated Arnott 3.17 - - Virkkula 3.27 3.36 1.65 Collaud Coen 3.26 3.31 1.75 9

Backman et al.: On Aethalometer measurement uncertainties and multiple scattering enhancement in the Arctic. 10 Manuscript submitted to AMT Discussions , 2016

IASOA sites Hyytiälä 11

New results, Krista Luoma’s MSc thesis C ref Collaud Coen C ref Weingartner C ref No ATN correction 12 Month

New results, Krista Luoma’s MSc thesis Effective complex refractive index by iterating scattering & absorption vs. size distributions Real Imaginary Month Month 13

CONNECTIONS TO IASOA? - Study of Arctic vs. boreal sites? - Statistics of episodes observed at SMEAR II, Pallas and maybe up to Ny Ålesund? - Other ways?