Aircraft Measurements of Icing in Supercooled and Water Droplet/Ice Crystal Clouds

Abstract

Icing measurements were carried out in Spain during the Precipitation Enhancement Project experiment in 1979, with an instrumented DC-7 aircraft. The energy balance at the riming surface of a cylinder allows the prediction of the ice growth regime (wet or dry) for the present measurements with 85% success. The mixed conditions encountered show that the ice phase plays an important role in the ice accretion process. For a range of temperature from −21 to −8°C, the icing rate appears to be reduced ∼50% by the presence of large ice particles in concentrations above 5 L⁻¹. The proposed explanation is that the ice particles erode the ice deposit formed by the supercooled water.