From hygroscopic aerosols to cloud droplets: The HygrA-CD campaign in the Athens basin - An overview

A Papayannis; A Argyrouli; A Bougiatioti; E Remoundaki; S Vratolis; A Nenes; S Solomos; M Komppula; E Giannakaki; J Kalogiros; R Banks; K Eleftheriadis; E Mantas; E Diapouli; C G Tzanis; S Kazadzis; I Binietoglou; L Labzovskii; J Vande Hey; C S Zerefos

doi:10.1016/j.scitotenv.2016.09.054

From hygroscopic aerosols to cloud droplets: The HygrA-CD campaign in the Athens basin - An overview

Sci Total Environ. 2017 Jan 1:574:216-233. doi: 10.1016/j.scitotenv.2016.09.054. Epub 2016 Oct 14.

Authors

A Papayannis¹, A Argyrouli², A Bougiatioti³, E Remoundaki⁴, S Vratolis⁵, A Nenes⁶, S Solomos⁷, M Komppula⁸, E Giannakaki⁹, J Kalogiros¹⁰, R Banks¹¹, K Eleftheriadis¹², E Mantas⁴, E Diapouli¹², C G Tzanis¹³, S Kazadzis¹⁴, I Binietoglou¹⁵, L Labzovskii¹⁶, J Vande Hey¹⁷, C S Zerefos¹⁸

Affiliations

¹ Laser Remote Sensing Unit, Physics Department, School of Applied Mathematics and Physical Sciences, National Technical University of Athens, 15780 Zografou, Greece. Electronic address: apdlidar@central.ntua.gr.
² Laser Remote Sensing Unit, Physics Department, School of Applied Mathematics and Physical Sciences, National Technical University of Athens, 15780 Zografou, Greece.
³ Laser Remote Sensing Unit, Physics Department, School of Applied Mathematics and Physical Sciences, National Technical University of Athens, 15780 Zografou, Greece; School of Earth & Atmospheric Sciences, Georgia Institute of Technology, Atlanta 30332, GA, USA.
⁴ Laboratory of Environmental Science and Engineering, School of Mining and Metallurgical Engineering, National Technical University of Athens, 15780 Zografou, Greece.
⁵ Laser Remote Sensing Unit, Physics Department, School of Applied Mathematics and Physical Sciences, National Technical University of Athens, 15780 Zografou, Greece; ERL, INRSTES, N.C.S.R. Demokritos, 15310 Agia Paraskevi, Attiki, Greece.
⁶ School of Earth & Atmospheric Sciences, Georgia Institute of Technology, Atlanta 30332, GA, USA; ICE-HT, Foundation for Research and Technology, Hellas, 26504 Patras, Greece; Institute of Environmental Research and Sustainable Development, National Observatory of Athens, Athens, Greece; School of Chemical & Biomolecular Engineering, Georgia Institute of Technology, Atlanta 30332, GA, USA.
⁷ Institute for Astronomy, Astrophysics, Space Applications and Remote Sensing, National Observatory of Athens, Athens, Greece.
⁸ Finnish Meteorological Institute, Kuopio, Finland.
⁹ Finnish Meteorological Institute, Kuopio, Finland; Department of Environmental Physics and Meteorology, Faculty of Physics, University of Athens, Athens, Greece.
¹⁰ Institute of Environmental Research and Sustainable Development, National Observatory of Athens, Athens, Greece.
¹¹ Barcelona Supercomputing Center-Centro Nacional de Supercomputación (BSC-CNS), Earth Sciences Department, Jordi Girona 29, Edificio Nexus II, Barcelona, Spain; Environmental Modelling Laboratory, Polytechnic University of Catalonia, Barcelona, Spain.
¹² ERL, INRSTES, N.C.S.R. Demokritos, 15310 Agia Paraskevi, Attiki, Greece.
¹³ Climate Research Group, Division of Environmental Physics and Meteorology, Department of Physics, National and Kapodistrian University of Athens, 15784 Athens, Greece.
¹⁴ Institute of Environmental Research and Sustainable Development, National Observatory of Athens, Athens, Greece; Physikalisch-Meteorologisches Observatorium Davos, World Radiation Center, Switzerland.
¹⁵ National Institute of Research and Development for Optoelectronics, Magurele, Romania.
¹⁶ National Institute of Research and Development for Optoelectronics, Magurele, Romania; Research Center of Ecological Safety, Russian Academy of Sciences, St. Petersburg, Russia.
¹⁷ Department of Physics and Astronomy, Earth Observation Science Group, University of Leicester, University Road, Leicester LE1 7RH, UK.
¹⁸ Biomedical Research Foundation of the Academy of Athens, Athens, Greece; Navarino Environmental Observatory (N.E.O.), Messinia, Greece.

PMID: 27639019
DOI: 10.1016/j.scitotenv.2016.09.054

Abstract

The international experimental campaign Hygroscopic Aerosols to Cloud Droplets (HygrA-CD), organized in the Greater Athens Area (GAA), Greece from 15 May to 22 June 2014, aimed to study the physico-chemical properties of aerosols and their impact on the formation of clouds in the convective Planetary Boundary Layer (PBL). We found that under continental (W-NW-N) and Etesian (NE) synoptic wind flow and with a deep moist PBL (~2-2.5km height), mixed hygroscopic (anthropogenic, biomass burning and marine) particles arrive over the GAA, and contribute to the formation of convective non-precipitating PBL clouds (of ~16-20μm mean diameter) with vertical extent up to 500m. Under these conditions, high updraft velocities (1-2ms^-1) and cloud condensation nuclei (CCN) concentrations (~2000cm^-3 at 1% supersaturation), generated clouds with an estimated cloud droplet number of ~600cm^-3. Under Saharan wind flow conditions (S-SW) a shallow PBL (<1-1.2km height) develops, leading to much higher CCN concentrations (~3500-5000cm^-3 at 1% supersaturation) near the ground; updraft velocities, however, were significantly lower, with an estimated maximum cloud droplet number of ~200cm^-3 and without observed significant PBL cloud formation. The largest contribution to cloud droplet number variance is attributed to the updraft velocity variability, followed by variances in aerosol number concentration.

Keywords: Aerosol Raman lidar; Aerosol chemical properties; Athens; CCN; Cloud development; Cloud droplet number; Doppler lidar; FLEXPART model; Greece; HygrA-CD; Precipitation radar; SMPS; WRF.