梅雨前線帯中間規模対流系の予報実験

Abstract

Forecast experiments on a long-lived meso-α-scale convective system (MaCS) in the Baiu frontal zone were made by using a 13-level 64km-mesh primitive equation model. This MaCS passed over the East China Sea and Kyushu (western part of Japan) on 14 July 1979 and developed into a Baiu frontal depression when it moved over the Pacific coast of Japan on 15 July 1979. Three 24-hour forecast experiments (Exp. CNT: control experiment, Exp. SMM: experiment from the initial condition of small specific humidity in the lower troposphere, and Exp. HET: experiment with the prescribed condensation heating in the first 1-hour of the time integration) were made from the initial state at 09LST 14 July 1979.The result of Exp. CNT showed slow spin-up of the MαCS in the early few hours. The spin-up of the MαCS in Exp. SMM was significantly slower than that in Exp. CNT. Exp. HET indicated improvement of the MαCS's spin-up. The forced condensation heating in the first 1-hour had strong influence throughout the whole integration period. The timely spin-up of the MαCS caused by the forced heating in the model resulted in the timely change of circulations around the MαCS, and this change contributed to the further development of the MαCS and the associated Baiu frontal depression.