Detection of aircraft icing conditions with a surface radiometer

It has been observed that the type and intensity of icing on the Wyoming King Air (N2UW) varies according to the type of icing environment. There are four types of icing environments: (i) Stratiform cloud with low ice particle concentrations (SO); (ii) Stratiform cloud with high ice particle concentrations (SI); (iii) Cumuliform cloud with low ice particle concentrations (CO); (iv) Cumuliform cloud with high ice particle concentrations (CI).;Icing in SO environments proved the most hazardous to N2UW. However, conventional forecasting techniques used for civilian and military aviation do not recognize the existence of hazardous icing conditions in stratiform clouds. This study tests the ability of the mean and standard deviation of vertically integrated liquid water (VILW) from a ground-based radiometer to distinguish among the various types of icing environments.;Statistical analyses applied to the mean and standard deviation of VILW showed that these parameters have limited ability to distinguish among SI, SO, CO and CI environments when using VILW averaging periods of 90 min or more. Further analyses showed the mean and standard deviation of VILW have limited ability to distinguish hazardous (SO) from non-hazardous (SI) icing environments when using averaging periods of 240 min or more.;Thus, it is concluded that the mean and standard deviation of VILW have limited ability to provide useful information concerning details of the aircraft icing environment. However, it is emphasized that the data used in this study came from the Sierra Nevada of California, thus the mountainous terrain may have produced sufficient inhomogeneity in the clouds to convolute the results.