On the Cloud Structure Related to Heavy Rainfall as Revealed by Radar

On Convective Clouds at Owase in the Cases of Heavy Rain

“…If we think so, it may be inferable that small scale or shallow convective clouds such as seen in Fig. 13, having cloud top of 3 to 5km often occur around the Owase area in the cases of heavy rain and play in fact some important roles for the occurrence of heavy rain as described by Fujiwara et al (1974). Table 4 shows the cases in which obtained cloud heights are in 1 to 5km when we assume no excess temperature at cloud base.…”

“…Summarizing those results we may conclude that the occurrence of such shallow convective clouds is not rare around the Owase area in cases of heavy rain but we may be able to expect those clouds with considerable frequency. If so, those clouds may play in fact some important roles on the occurrence of heavy rain as Fujiwara et al (1974) point out.…”

“…On the mechanism of heavy rain, Fujiwara et al (1974) pointed out of the role of shallow convective clouds from the viewpoint of the multiplication of precipitation intensity by cloud water collection. With relation to this study, the problem of convective clouds at Owase in the cases of heavy rain, especially the height of those cloud tops and their frequency distribution was investi-gated with use of a simple numerical model of cumulus convection.…”

“…(After Fujiwara et al, 1974) Then at decaying stage nearly whole the depth of the cloud is occupied by downdraf t. The life time or the typical duration time is roughly estimated about one hour or so. Judging from the above discussion and the implication of Fig.…”

“…2). On the mechanism of heavy rain, Fujiwara et al (1974) pointed the probability of the role of shallow convective clouds which accompany with considerable amount of cloud water and updraft, within which it is considered that falling raindrops from upper layer collect cloud or rainwater and result in strong precipitation intensity at the ground surface, by carrying a simple numerical computation in their study on the cloud structure related to heavy rainfall.…”