Structure and Evolution of a Slow-moving Rain-band

Xiao Meng

The three-dimensional structure and evolution of two meso-β-scale slow- moving rain-bands are studied in detail mainly by using the data of dual Doppler- radars. The two rain-bands were observed on Sep.16,1994 around Nagoya. Bands were formed and maintained in the environment in which strong vertical shear existed at low-level. They had the orientation from southeast to northwest, nearly parallel to prevailing southeasterly winds from the surface to about 4 km, and hardly moved in the direction mormal to the band orientation. Rain-bands were mainly composed of several long-lasting convective-cloud groups which were maintained by the successive formation of new convective cells at the tail portion of the group. Most of convective-cloud groups also formed at the tail part of the rain- band. Both convective-cloud groups and cells moved along the orientation of the band. Most of new cells were produced at the rear of a traveling pre-existingcell, not its right or left frank, in spite of the low-level vertical shear of normal wind component.