1. NASA Icing Remote Sensing Andy Reehorst NASA Glenn Research Center Dave Serke NCAR

2. Icing Remote Sensing Goals/Vision Develop technologies that will enable terminal area sensing and airborne sensing. Implement through incremental development starting at ground-based vertical staring. Current Capability Ground-based goal Airborne goal Current Focus

3. Current vertical-pointing Icing R-S NASA Icing Remote Sensing System (NIRSS) Sensors Radar Provides cloud boundaries Multi-frequency Microwave Radiometer Provides Temperature Profile Provides Integrated Water Content Ceilometer Refines cloud base boundary

4. Current vertical-pointing Icing R-S Simplified Algorithm Radar provides cloud profile Radiometer provides temperature profile Radiometer provides integrated liquid water path Distribute liquid water over cloud extent for LWC Derive droplet size Reflectivity is a function of both cloud droplet size and liquid water content Can do this because our water content and radar reflectivity are independent measurements Use temperature, water content, droplet size to determine icing hazard

5. Current vertical-pointing Icing R-S NIRSS (left) and CIP (right) Probability of Detection (POD) (positive and negative) compared to PIREPS. Altitude/Time plots of NIRSS (top), PiReps (top, red numbers), and CIP (bottom) **Note the larger warning band for CIP** Recent comparison of NIRSS and CIP relative to PIREPS Based upon 3 years of NIRSS data (operating at GRC) “NIRSS detected almost 80% of positive PIREPs and over 70% of negative PIREPs in a relatively smaller warning volume. CIP detected slightly more positive PIREPs than NIRSS but did fairly poor in detecting negative PIREPs.” From: Johnston, C.J., et al, “Comparison of In-Situ, Model and Ground-Based Inflight Icing Severity”, NASA /TM-2011-217141, Dec 2011.

6. Current scanning Icing R-S Sensor Systems Radiometrics MP3000A 35 channel Temperature, Water Vapor and Liquid Profiler 21 channels in K-band 22-30 GHz 14 channels in V-band 51-59 GHz Optional Azimuth Positioner Optional Infrared Thermometer Located on NASA GRC Icing Research Tunnel balance chamber roof Vertical and 15 deg slant elevation measurements Slant measurements made at CLE runway headings Provides temp profiles and integrated liquid water measurements for vertical and 15 degree elevations with Radiometrics neural nets Radiometrics Narrowbeam Radiometer Uses Radiometrics’ PR-series receivers K-band multichannel receiver (21 channels in 22-30GHz) W-band polarized receiver (89 GHz) Located on NASA GRC Icing Research Tunnel shop roof Provides integrated liquid water measurements over all slant angles with algorithms from Dr. Ulrich Lohnert from the University of Cologne

7. Current scanning Icing R-S FEATURES 1 deg beam widths Upgraded elevation and azimuth scanning (Moog Quickset QPT-500) Integrated Garmin 17 HVS GPS (time) and Vaisala WXT520 Met (temp, RH, wind, precip) Rain Mitigation (radiometer lens blower and reflector hydrophobic coating) CURRENT PLANS Install version 3 RadScan software Install support mod kits Changes intended to address operational problems (structure flex, positioner freezes, software bugs) Will add tip calibration capability NASA Narrow-beam Multi-frequency Microwave Radiometer Developed by Radiometrics, Inc. of Boulder, CO under SBIR and Aviation Safety Program funding