Das Projekt "An investigation into the effects of aerosol on cold clouds" wird vom Umweltbundesamt gefördert und von Max-Planck-Institut für Chemie (Otto-Hahn-Institut) durchgeführt. General Information: Over the next 12 months the UK Meteorological Research Flight's C-130 Hercules aircraft is being fitted with novel new instrumentation for (a) automatically measuring small ice particles (l-100, um) and distinguishing them from super cooled water droplets in cold clouds, (b) determining the concentrations of IN in the free troposphere, (c) collecting and analysing cloud particle residuals to determine if they have CCN or IN characteristics. These sorts of measurements have never been possible before and as a result studies into how clouds glaciate and the effect of aerosols on cold clouds have been severely limited. This project intends to make full use of these advances and it is proposed that a four week field programme will be undertaken in northern Europe where the C-130 will make measurements in orographic and frontal layer clouds. The main objectives will be to: (a) determine the physical, chemical, and cloud nucleating properties of the aerosol in the free troposphere over northern Europe and investigate the relationships between these properties (b) quantify the physical and chemical processes controlling the activation or nucleation of ice particles in layer clouds and orographic clouds over northern Europe (c) develop parameterisations of the glaciation processes in clouds for inclusion in large scale numerical models. The results from this experiment will be analysed in conjunction with several process models in order to ascertain whether homogeneous or heterogeneous processes are dominating in the production of ice particles in clouds or whether there is an interaction between the two processes that varies with the environmental conditions. If successful the results from this experiment can be used to develop large scale model parameterisations of cloud glaciation which will enable better global circulation and climate predictions to be made. Prime Contractor: Defence Evaluation and Research Agency (DERA), Meteorological Office; Farnborough; UK.