Representative Values of Icing-Related Variables Aloft in Freezing Rain and Freezing Drizzle.

• Main Author: Jeck, Richard K.
• Other Authors: FEDERAL AVIATION ADMINISTRATION TECHNICAL CENTER ATLANTIC CITY NJ
• Format: Text
• Language: English
• Published: 1996
• Subjects: Meteorology; Snow; Ice and Permafrost; Commercial and General Aviation; *ICE FORMATION; *RAIN; *AVIATION ACCIDENTS; AIRCRAFT; AIRCRAFT MAINTENANCE; AIR FLOW; ATMOSPHERIC TEMPERATURE; METEOROLOGICAL DATA; WEATHER FORECASTING; TEMPERATURE GRADIENTS; FREEZING; RAINDROPS; FUSELAGES; WIND SHEAR; TAKEOFF; CIVIL AVIATION; RADIOSONDES; AVIATION SAFETY; SURFACE TEMPERATURE; CLOUD COVER; AIRCRAFT LANDINGS; HUMIDITY; ICE FORECASTING; ICE PREVENTION; *AIRCRAFT ICING; ATMOSPHERIC BOUNDARY LAYER; Ice; permafrost
• Online Access: http://www.dtic.mil/docs/citations/ADA307822; http://oai.dtic.mil/oai/oai?&verb=getRecord&metadataPrefix=html&identifier=ADA307822

Radiosonde and surface observations in freezing rain (ZR) and freezing drizzle (ZL), and a limited number of aircraft measurements in ZR, have been examined for information on the magnitude and altitude dependence of meteorological variables associated with aircraft icing in these conditions. The variables include temperature aloft, humidity (clouds), and windshear from the radiosondes; surface temperatures, ceiling heights, precipitation type and amount from the surface observations; and temperature, dropsize, rainwater concentration, and icing rate from the instrumented aircraft. These and other data are used here to arrive at tentative maximum and representative values of these variables. To overcome the inadequacy of median volume diameter (MVD) as a measure of dropsize for these large droplet conditions, a convention for reporting the ZR or ZL water concentration over a few coarse dropsize intervals is proposed.