Insights into Cirrus Ice Habit Microphysics from POSIDON

The life cycle of cirrus clouds is heavily influenced by the microphysical processes affecting the number concentration, shape, and size of the individual ice crystals. Improving our understanding of the competing effects of these processes will allow for improved modeling of cirrus evolution and quantification of cirrus radiative effects. Toward this end, the POSIDON (Pacific Oxidants, Sulfur, Ice, Dehydration, and cONvection) campaign flew 9 flights out of Guam in October of 2016, collecting observations of TTL (Tropical Tropopause Layer) cirrus under a variety of ambient conditions. For cloud microphysical observations, the NASA WB-57 was outfitted with an FCDP (Fast Cloud Droplet Probe), 2D-S (2D-Stereo Optical Array Probe), and a CPI (Cloud Particle Imager). Water vapor measurements were also provided by a Diode Laser Hygrometer (DLH), and temperature and winds by Meteorological Measurement Systems (MMS). Sampling captured observation of a variety of cirrus throughout the campaign, of both in situ and convective origination. Backward trajectories from the flight level were conducted to determine the time since most recent convective influence. Having classified ice particle habits of the CPI imagery, we present analysis of the influence of convection, winds, temperature, and supersaturation on the particle habit and related microphysics.