Analysis of Mesoscale Structure of Snow Clouds by Stereoscopic Treatment of Radar Pictures

Abstract

A stereoscopic treatment of successive radar pictures was devised for the analysis of movement of PPI radar echoes.
The stereoscopic method was applied to the analysis of mesoscale wind structure in snow clouds in the winter monsoon season in Hokkaido. The results of the analysis showed that the method was highly useful for analyzing such mesoscale structures, and it was discovered that mesoscale convergence and divergence zones were alternatively distributed and that they were vertical to the prevailing wind direction at the echo level.
The wave length of the alternative distribution of the zones was, about 20km, and it was considered that the distribution was originated from an internal gravitational wave disturbance. Considering the wave length, the disturbance analyzed, was of intermediate scale between cumulonimbus clouds and mesoscale disturbance of about 100km size previously found by Matsumoto, Ninomiya and Akiyama (1967) in snowy weather.