Open AccessCharacterization of Aircraft Icing Environments with Supercooled Large Drops for Application to Commercial Aircraft Certification
Author(s) -
Stewart G. Cober,
George A. Isaac
Publication year - 2012
Publication title -
journal of applied meteorology and climatology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.079
H-Index - 134
eISSN - 1558-8432
pISSN - 1558-8424
DOI - 10.1175/jamc-d-11-022.1
Subject(s) - icing , icing conditions , environmental science , supercooling , liquid water content , meteorology , ice crystals , freezing rain , drop (telecommunication) , atmospheric sciences , materials science , snow , physics , computer science , cloud computing , operating system , telecommunications
Observations of aircraft icing environments that included supercooled large drops (SLD) greater than 100 μ m in diameter have been analyzed. The observations were collected by instrumented research aircraft from 134 flights during six field programs in three different geographic regions of North America. The research aircraft were specifically instrumented to accurately measure the microphysics characteristics of SLD conditions. In total 2444 SLD icing environments were observed at 3-km resolution. Each observation had an average liquid water content (LWC) > 0.005 g m −3 , drops > 100 μ m in diameter, ice crystal concentrations 500 μ m in diameter, each with median drop volume diameters 40 μ m. For each SLD subset, the observations were used to develop envelopes of maximum LWC values as a function of horizontal extent and temperature. In addition, characteristic drop size distributions were developed for each SLD subset. The maximum LWC values physically represent either the 99% or 99.9% LWC values, as determined from an extreme value analysis of the data. The analysis is sufficient for simulation of SLD environments with either numerical icing accretion models or wind-tunnel icing simulations. The SLD envelopes are similar in structure and supplemental to existing aircraft icing envelopes, the difference being that the existing envelopes did not explicitly incorporate SLD conditions.