Supercooled drizzle formed by condensation-coalescence in the mid-winter season of the Canadian Arctic

Supercooled drizzle freezing drizzle was observed at Inuvik, N.W.T., Canada 68 degrees 22(X)N, 133 degrees 42(X)W on December 20, 21 and 27, 1995. Met eorological conditions in which the supercooled drizzle could form under lo w temperatures colder than y20 degrees C in the mid-winter season of the Ca nadian Arctic were examined from the sounding data and data measured by a p assive microwave radiometer at ground level. The following results were obt ained. 1. Supercooled drizzle fell to the ground with ice pellets and froze n drops on snow crystals. 2. The maximum size of supercooled drizzle partic les increased as the depth of cloud layer saturated with respect to water i ncreased. 3. Because a layer of air temperature higher than 0 degrees C was not detected from the sounding data at Inuvik, melting of snow particles w as impossible. It was concluded, therefore, that supercooled drizzle was fo rmed by the condensation-coalescence process below freezing temperature. (C ) 2000 Published by Elsevier Science B.V. All rights reserved.