Observations of cloud microphysical properties in cirrus during the Airborne Tropical TRopopause Experiment (ATTREX)

We present aircraft measurements made by a Fast Cloud Droplet Probe (FCDP) and Hawkeye probe flown on the NASA Globalhawk during the Airborne Tropical TRopopause Experiment (ATTREX). Cirrus systems near the Tropical Tropopause Layer (TTL) were sampled during flights from California to the tropics in 2011 and 2013, and from Guam in the western Pacific in 2014. The FCDP was present in all three years, and the Hawkeye was a new addition to the flights in 2014. The Hawkeye is a combination cloud droplet probe, 2-D stereo imaging array probe with 10 um resolution channels, and a high-resolution cloud particle imager, providing particle concentrations and sizing between 1 and 1280 um as well as particle images for ice habit identification. Measurements made by a NOAA instrument onboard the aircraft which measures both water vapor and total water, as well as pressure and temperature measurements made by MMS are used to derive estimates of the supersaturation with respect to ice, which demonstrates good correlation with observations of cloud particles by the FCDP and Hawkeye. We present the variability in ice concentrations, particle size distributions and in particle habit as a function of temperature, supersaturation with respect to ice, and cirrus type.