HIWC-RADAR II Collins Aerospace Optical Ice Detector Measurements This data set includes the meaurements acquired from the Collins Aerospace Optical Ice Detector (OID) during the HIWC-RADAR II flight campaign. The Optical Ice Detector is a polarimetric cloud LIDAR system capable of discriminating cloud phase and measuring water content. Cloud phase and water content are computed from measurements of optical extinction, backscatter, and depolarization derived from cloud LIDAR reflections. Probe Specifications: These data were acquired using the 4th generation Collins Optical Ice Detector. The device samples clouds through a combination of a 15W 905 nm diode laser pulsed at a rate of 2500 Hz and 2" receiver optics. LIDAR reflections are digitized at a 0.6 meter range resolution. Processing Details: Measurements are based on 1 Hz averages of cloud LIDAR reflections. Cloud detection, cloud phase, LWC, IWC, and TWC measurements are provided as follows: Output Name Type Units Description -------------- --------- --------- ----------------- Cloud Detected Boolean (True / False) Active when the presence of a cloud is detected by the OID Cloud Phase Discrete (0 / 1 / 2) 0: Phase of the detected cloud is indeterminate due to low signal intensity 1: Liquid water droplets are present, ice crystal content is below the OID detection threshold 2: The detected cloud contains ice crystal content greater than the OID ice crystal detection threshold LWC Numeric g/m3 Liquid water content in grams per cubic meter IWC Numeric g/m3 Ice water content in grams per cubic meter TWC Numeric g/m3 Total water content in grams per cubic meter File format and naming convention: OID measurements are saved in CSV (comma separated values) format. In addition to the OID outputs listed above, a timestamp for each measurement is provided in units of seconds from midnight UTC. OID data files are named with the following convention: YYYY_MM_DD_HHMMSS.OID.1Hz where YYYYMMDD = year, month and day HHMMSS = hour, minutes, and seconds at data start time References: Ray, M., Nesnidal, M., and Socha, D., “Optical Detection of Airborne Ice Crystals and Water Droplets,” Paper AIAA 2009-3863, presented at the 1st AIAA Atmospheric and Space Environments Conference, San Antonio, TX, June 22-25, 2009. Halama, G., Ray, M., Anderson, K., and Nesnidal, M., “Optical Ice Detection: Test Results from the NASA Glenn Icing Research Tunnel,” Paper AIAA 2010-7532 presented at the 2nd AIAA Atmospheric and Space Environments Conference, Toronto, ON, August 2-5, 2010. Anderson, K., Halama, G., Ray, M., and Nesnidal, M., “Cloud Phase Discrimination Using the Optical Icing Conditions Detector: Wind Tunnel and Flight Test Results,” Paper 11ICE-0011 in SAE, 2011. Ray, M., and Anderson, K., “Analysis of Flight Test Results of the Optical Ice Detector,” Paper 2015-01-2106, presented at the SAE 2015 International Conference on Icing of Aircraft, Engines, and Structures, Prague, Czech Republic, June 22-25, 2015.