FIELD VALIDATION OF THE DROPLET AEROSOL ANALYZER

A new instrument for the study of cloud droplets and its relation to a erosol particles, the droplet aerosol analyser (DDA), was for the firs t time used in a field campaign. The DAA has the unique feature of mea suring the ambient size of cloud droplets or cloud interstitial aeroso l particles together with the size of its dry residue. This is obtaine d with a two-parameter data acquisition technique which results in a t hree-dimensional data set (ambient size, dry residue size, number conc entration). The principle and design of the DAA is briefly described. The DAA was intercompared with differential mobility particle sizers, particulate volume monitors and a forward scattering spectrometer prob e with respect to interstitial and cloud droplet dry residue size dist ribution as well as particle-size-dependent scavenging due to cloud dr oplet nucleation and for cloud droplet number concentration and size d istribution and cloud liquid water concentration. Overall, the DAA sho wed good agreement with respect to all these six aerosol/cloud propert ies. (C) 1997 Elsevier Science Ltd.