Two Cases Studies of Cloud Structures of Aircraft Icing Tests in the Northwest of China

Two tests of aircraft icing observations were conducted on March 2018 in Xin Jiang in northwest of China. The icing conditions are studied using observations of satellite, radar, soundings and simulations using the WRF mesoscale model coupled with CAMS cloud scheme. The large-scale weather systems of the two icing cases are the vortex and the shallow trough on 500hPa separately, accompanied by the cold front on the surface. The icing time is in the early stage of vortex system and the middle stage of shallow trough system. The icing clouds are both low and middle clouds. The cloud top height is 4km and the cloud top temperature is -15~-25℃. The cloud bottom height is 1.5km and the cloud thickness is 1-3km. The optical thickness is larger than 12 and the radar reflectivity is less than 10dBZ. There is an inversion layer of the shallow trough. The microphysical structures of CPEFS model simulations show that the icing cloud is composed of large number of supercooled water and few ice particles. The CIP initial icing potential results can basically reflect the icing height and time of the two cases.