Observation of Wintertime Clouds and Precipitation in the Arctic Canada (POLEX-North)

[摘要] Observations of wintertime clouds and precipitation were made from Nov, in 1979 to Jan. 1980 at Inuvik in Northwest Territories of Canada. Following conclusions about the charac-teristic features of clouds and precipitation were reached mainly by analysing the data of upper-air sounding and our radar observation. Three types of clouds were observed frequently during the observation period. In type I clouds the lapse rate of temperature is nearly moist-adiabatic, in type II clouds temperature hardly changes with height and in type III clouds it increases with height. In warm period types I and III clouds were observed and they often constituted a two-layers cloud system. In cold period type II clouds were often observed, and they tended to be more persistent and deeper than types I and III clouds. Most of type II clouds were detected by a vertically pointing radar of 8.6mm in wave-length, though they were not identified clearly by eye observation in many cases. They are inferred to have been composed of large ice particles whose number concentration was not high. During the obser-vation period precipitation originated from type II clouds occupied about 30% of the total period of precipitation and it contributed to about 20% of total precipitation amount.

[学科分类] 大气科学