An overview of the ACE-2 CLOUDYCOLUMN closure experiment

J.-L. Brenguier (1) , P. Y. Chuang (2) , Yves Fouquart (3) , D.W. Johnson (4) , Frédéric Parol (5) , Hanna Pawlowska (6) , Jacques Pelon (7) , Lothar Schüller (8) , F. Schröder (9) , J. R. Snider (10)

1 CNRM - Centre national de recherches météorologiques
2 CALTECH - California Institute of Technology
3 LOA - Laboratoire d’Optique Atmosphérique - UMR 8518
4 MRF - Meteorological Research Flight
5 IRN - Interactions Rayonnement Nuages
6 LMD - Laboratoire de Météorologie Dynamique (UMR 8539)
7 SA - Service d'aéronomie
8 Institut für Weltraumwissenschaften [Berlin]
9 DLR - Deutsches Zentrum für Luft- und Raumfahrt
10 Department of Atmospheric Science [Laramie]

CLOUDYCOLUMN is one of the 6 ACE-2 projects which took place in June-July 1997, between Portugal and the Canary Islands. It was specifically dedicated to the study of changes of cloud radiative properties resulting from changes in the properties of those aerosols which act as cloud condensation nuclei. This process is also refered to as the aerosol indirect effect on climate. CLOUDYCOLUMN is focused on the contribution of stratocumulus clouds to that process. In addition to the basic aerosol measurements performed at the ground stations of the ACE-2 project, 5 instrumented aircraft carried out in situ characterization of aerosol physical, chemical and nucleation properties and cloud dynamical and microphysical properties. Cloud radiative properties were also measured remotely with radiometers and a lidar. 11 case studies have been documented, from pure marine to significantly polluted air masses. The simultaneity of the measurements with the multi-aircraft approach provides a unique data set for closure experiments on the aerosol indirect effect. In particular CLOUDYCOLUMN provided the 1st experimental evidence of the existence of the indirect effect in boundary layer clouds forming in polluted continental outbreacks. This paper describes the objectives of the project, the instrumental setup and the sampling strategy. Preliminary results published in additional papers are briefly summarized.

Domaines: Physique Atmosphérique et Océanique [physics.ao-ph]

J.-L. Brenguier, P. Y. Chuang, Yves Fouquart, D.W. Johnson, Frédéric Parol, et al.. An overview of the ACE-2 CLOUDYCOLUMN closure experiment. Tellus B - Chemical and Physical Meteorology, 2000, 52 (2), pp.815-827. ⟨10.1034/j.1600-0889.2000.00047.x⟩. ⟨hal-00811562⟩