Analysis of cirrus cloud particle size distributions from Sparticus

The Atmospheric Radiation Measurement (ARM) program's Small Particles in Cirrus (SPARTICUS) flight campaign, currently in operation in the vicinity of ARM's Southern Great Plains site, is accumulating many hours of cirrus cloud measurements using combinations of ground- and space-based remote sensors and airborne in situ sensors. In situ measurements of cirrus cloud ice particle size distributions (PSD's) are being gathered using a range of probes to include the Spec, Inc 2- D Stereo (2DS) probe. Bi- and mono-modal PSD's, measured by the 2DS concurrently with several atmospheric state and meteorological variables, are here described analytically using gamma size distribution functions. These PSD's are then aggregated into groups based on ancillary meteorological measurements. Relationships between meteorological regime and probability distributions of fitted gamma function size and shape parameters are thereby revealed.