Early Ice Particles in Growing Convective Clouds over a New Mexico Mountain Range during DCMEX

The formation of the first ice particles in developing convective clouds is a critical event in cloud evolution. The timing, location and amount of the initial ice has potentially significant implications for the eventual micro and macro scale properties as the cloud evolves. Here we present in-situ measurements of the first ice particles observed in growing convective clouds during the DCMEX project over the Magdalena mountains in New Mexico, USA. The Facility for Airborne Atmospheric (FAAM) Bae-146 research aircraft was used to make penetrations of the convective clouds below the freezing level, following the cloud top upwards. We used an Optical Array probe with a large sample volume suitable for detecting the earliest ice particles as they developed. We often observed no ice particles initially at only slightly supercooled temperatures before the eventual appearance of small irregular ice particles in low concentrations around the -8°C level. We will present the characteristics of the particles observed and compare their concentrations with Ice Nucleating Particle (INP) data analysed during the same project.