Discrimination of micrometre-sized ice and super-cooled droplets in mixed-phase cloud

Preliminary experimental results are presented from an aircraft-mounted pro be designed to provide in situ data on cloud particle shape, size, and numb er concentration. In particular, the probe has been designed to facilitate discrimination between super-cooled water droplets and ice crystals of 1-25 mum size within mixed-phase clouds and to provide information on cloud int erstitial aerosols. The probe acquires spatial light scattering data from i ndividual particles at throughput rates of several thousand particles per s econd. These data are logged at 100ms intervals to allow the distribution a nd number concentration of each particle type to be determined with 10m spa tial resolution at a typical airspeed of 100ms(-1). Preliminary results fro m flight data recorded in altocumulus castellanus, showing liquid water pha se, mixed phase, and ice phase are presented to illustrate the probe's part icle discrimination capabilities. (C) 2000 Elsevier Science Ltd. All rights reserved.