夏季積乱雲発達初期の雲レーダー観測

Abstract

In summer season in Japan, cumulonimbus clouds frequently develop when solar insolation heats land surface. Some of cumulonimbus clouds are considerably intensified and short-term intense rainfalls occur. This short-term intense rainfalls cause abrupt rise of rivers and inflow of large amount of water into underground, which occasionally result in disasters. To detect clouds largely developing from the present time as much as earlier, we conducted an observation for initial development stage of summer cumulonimbus clouds using a cloud radar in the 2017 summer season in Kobe. The cloud radar is sensitive smaller particles than precipitation particles. Fine structures of the cumulonimbus clouds were shown using high-resolution cloud radar data. It was pointed out that horizontal scales of cumulonimbus clouds at initial development stage are important for development of convection with less entrainment and less buoyancy loss.