Squall Line Like Convective Snowbands over the Sea of Japan

Abstract

This paper describes the internal structure of two convective snowbands, deduced by using mainly single-Doppler radar data, which developed over the Sea of Japan in winter, traveled nearly perpendicularly to their orientation, and showed common features.A typical snowband was formed in a convective mixed layer 4km deep over the relatively warm sea surface in the early stage of a cold-air outbreak. This snowband was a multicell system which contained two or three echo cells in a vertical plane normal to its orientation. Each echo cell developed aloft in the forward portion of the snowband and became a mature echo cell in the middle of the snowband. The upper portion of old cells remains in a small anvil with low reflectivity below the stable layer in the rear part of the snowband. The snowband had the main updraft in its forward portion. The updraft tilted upshear and penetrated the stable layer above the convective mixed layer. There was a descending current from rear to front relative to the snowband in the lower half of the anvil. Snow particles evaporated in the downdraft. The leading edge of the downdraft was observed on the ground as a gust front with a severe gust and a drop in temperature of *1*.The circulation and maintenance mechanism of the convective snowbands was similar to those of tropical and midlatitude squall lines.

Doppler Radar Analysis of the Structure of Mesoscale Snow Bands Developed between the Winter Monsoon and the Land Breeze

“…14b) appeared in the mature stage with a value of 0.5ms-1 and gradually weakened. Sakakibara et al (1988b) presented the structure of mesoscale snow bands which occurred in the present experimental region, but were not associated with the land breeze. These snow bands had deeper and stronger vertical motion than snow bands of the present study due to the existence of a middle level cold vortex and relatively intense winter low-level monsoon.…”

“…Sakakibara et al (1988a) classified mesoscale snow cloud systems developed during the experiment using satellite data. Making use of the Doppler radar data taken during the experiment, they also showed that one of mesoscale snow bands had a structure similar to that of mid-latitude and tropical squall lines, although the snow band was of a smaller scale (Sakakibara et al, 1988b). Further, Ikawa of al.…”

Sensitivity Experiments on the Orographic Snowfall over the Mountainous Region of Northern Japan

“…This simple rationale has been widely accepted from old times, while the mechanisms of the snowfall on this region from cloud microphysical aspects have not been fully investigated. Although several studies for the winter snowfall have been made from a statistical (e.g., Fukuda, 1965;Ishihara, 1968;Mizuno, 1992) and observational (e.g., Sakakibara et al, 1988) point of view, only a few numerical experiments using an explicit cloud model with orography have been made in Japan. Ikawa et al (1987) and Ikawa (1988) simulated a convective cloud band over the Sea of Japan by use of a 2-dimensional model with a bulk parameterization scheme of cloud microphysics including ice phase.…”

Statistical Characteristics of Graupel Precipitation over the Japan Islands

“…Mesoscale vortex-like disturbances were analyzed by Asai and Miura (1981), and mesoscale snow bands were observed with a doppler radar (Sakakibara et al, 1988;Ishihara et al, 1989;Tsuboki et al, 1989). Recently a polar low developed over the Japan Sea was described by and Nic1992, Meteorological Society of Japan nomiya and .…”