大阪湾周辺における夏期の降雨生起特性

Abstract

Some observations have indicated that rainfall in urbanized areas posesses different characteristics than those in the suburban areas. In this paper we studied rainfall in the very urbanized area around Osaka Bay, focusing especially on rainfall in the summer (August). This season was chosen because during the summer large-scale phenomenon like typhoons or seasonal rain fronts hardly occur and it is thought that some urbanized factors which affect rainfall could be more easily found.We mainly analyzed when and where weak or heavy rainfall occurs using radar raingage data. As a result, the following was found:(1) weak rainfall tends to occur along the coastline and a big thermal power plant may have been the cause of it, (2) heavy rainfall tends to occur around the coastline and the mountainous areas in the evening after a series of hot days, and can also occur along a big river.