Mobile Cascade Impaction System (MOCIS)

Measuring campaigns 2001

During the AFS research project

07 AF 103/2
Vertical and temporal variation of size distribution and composition
of aerosol particles above distinct populated regions with respect
to primary biological aerosol particles

measuring flights with the MOCIS-instrumentation were performed on behalf of the Institute for Physics of the Atmosphere (IPA) in Mainz.

MOCIS is a modular and fully automated isokinetic aerosol sampling system, which was mounted for the airborne measurements in two underwing containers of the research aircraft Partenavia P68 B D-GERY.

This aircraft was choosen because of its short term availability, which allows to perform measuring flights within „synoptical scales“. The aircraft, which is part of the enviscope concept for the dual use of aircraft, was transferred from the mode „operation for photogrammetry“ to the mode „atmospheric investigations“ on short notice according to the predicted weather conditions. When the weather conditions seemed to be favourable to perform measuring flights within the next days, the operator of the aircraft was contacted and the aircraft was requested. If the weather developed according to the forecast, the aircraft was blocked for other use latest twenty-four hours in advance. Early in the morning of the first measuring day we drove to the airport and started to remove the photogrammetric equipment and to install the MOCIS instrumentation. Three hours later we were ready to take off!

Between May and August 2001 in total 21 measurements took place over congested and rural areas in Germany. Some flights were performed in the lee and luff of the areas of Mannheim/Ludwigshafen and the Ruhr Basin while rural atmospheric conditions were investigated in regions of the Palatine Forest and near the border between the Netherlands and Germany.

During the flights Aerosol Particles (AP) were collected size-fractionated for later analysis by IPA. The samples were analysed using light microscopes and scanning electron microscopes and the fraction of the Primary Biological Aerosol Particles (PBAP) was determined using EDX (Electron Disperse X-Ray Spectral Analysis). These first vertical profiles of PBAP were presented by IPA at different conferences and in various journals.

For detailed information about the discrimination of PBAP from AP and about the scientific results of the MOCIS measuring campaigns please contact IPA Mainz.

Another deployment of MOCIS mounted to the Partenavia P68B D-GERY has been performed in May 2005 during the „Saharan Mineral Dust Experiment (SAMUM)“. This research project, which was funded by the Deutsche Forschungsgemeinschaft, was dedicated to the understanding of radiative effects in the source region of Saharan mineral dust. In order to estimate direct and indirect radiative effects of atmospheric aerosol particles, size resolved information in the size range from 50 nm in diameter up to approximately 100 µm is required. The size distribution of the total aerosol and the different components (e.g., mineral, biological, anthropogenic components) have been analyzed. These measuring flights have been performed in the South of Morocco.

For further information please refer to the SAMUM homepage at IfT Leipzig or have a look to our SAMUM-page.