Ice nucleus measurements: effect of site location and weather

Abstract
Filter samples of atmospheric aerosol were collected daily at a city and a rural site over anextended period. The filters were processed in an environment supersaturated with respect to icein order to activate ice nuclei. The concentration of nuclei detected at the two sites was comparedwith reference to the local weather and air-mass trajectories. The city environment generally hasa larger ice nucleus concentration than the rural site. However, fluctuations in the concentrationsat the two sites are usually in phase, indicating a pre-dominantly common origin. With air-masstrajectories over industrial regions, the nucleus concentration is increased. Local weather has aprofound effect: in particular, rain and snow cause substantial reductions in ice nucleusconcentration. DOI: 10.1111/j.1600-0889.1985.tb00077.x