Overview of the Biogenic Aerosols -Effects on Clouds and Climate (BAECC) experiment

The Biogenic Aerosols -Effects on Clouds and Climate (BAECC) experiment will provide a bridge from a 18-year long observation record to the impact of biogenic aerosol on clouds, precipitation and climate. This will be achieved by simultaneous observations of precursor vapor emission, aerosol, cloud and precipitation microstructure. This dataset will be used to: (1) link precursor emissions and aerosol, (2) link aerosol at the surface to aerosol in the mixing layer and free troposphere, (3) investigate the aerosol indirect effect on clouds and precipitation. To achieve these goals we deploy the Atmospheric Radiation Measurement Mobile Facility (AMF-2) in Hyytiälä, Finland during 2014 in order to capture the seasonable variability of biogenic aerosol at this boreal environment site. The experiment will take place at the University of Helsinki SMEAR II research station, which has been monitoring biosphere-atmosphere interactions continuously since 1996. The ARM AMF observations will be supplemented by tower and surface-based measurements of aerosol and precursor gases as well as airborne observations during intensive observation periods.The experiment will also benefit from existing measurements of precipitation provided by the Finnish Meteorological Institute observational network. The general aims and current status of the project will be described.