Characteristic Features of Supercooled Raindrops in the Mid-Winter Season of Arctic Canada

Supercooled raindrops were observed for several hours at Yellowknife, N.W.T., Canada on January 10, 1986. The characteristics of supercooled raindrops, such as the size distribution and the precipitation intensity, were examined from replicas obtained at about 10 or 15 minute intervals. The following main results were obtained: 1) The size distribution of supercooled raindrops was similar to the Marshall-Palmer distribution type. 2) Because a layer of air temperature higher than 0°C was not detected at Yellowknife from available idata, the melting of snow crystals is impossible. Accordingly, it seems reasonable to conclude that the supercooled raindrops were formed by the warm rain forming process. 3) The precipitation intensity, the water content, and the total number concentration of supercooled raindrops in general resemble the features of drizzle type rain.