A Consideration of Higher Concentration of Ice Crystals Based on Data from Two Kinds of Videosondes

A field observation campaign is outlined, and possible processes for a high concentration of ice crystals are examined. The instruments used are two kinds of videosondes, one of which is a balloon-borne surveyor of precipitation particle morphology with the capable of detecting electric charge of each particle. Another type of videosonde can take images of cloud particles by a TV camera with a high magnification.

Observations were performed during 3 winter seasons, and an observation site locates near the coastline of Japan Sea where snowstorm system frequently develops rapidly by the effects of Asian winter monsoon and warm sea surface temperature. Sixty vertical profiles of precipitation and cloud particles in clouds have been obtained, and in some clouds a high number concentration of ice crystals and a high graupel number concentration are observed with brittle-looking graupels, suggesting that the graupel-graupel collision is possibly an extra-type of production process of small ice particles. Another interest is that a huge amount of cloud water contribute likely to produce chains of ice particles which may reproduce a number of ice particles by breaking linkage. Quantitative examination will be also presented accounting ice nucleation.