2018 年 74 巻 5 号 p. I_283-I_288
The objective of this study is to verify the capability of Rapid Scan Observation (RSO) of Himawari-8 data for a deeper understanding of the development of cumulus cloud, which can generate Guerilla-heavy rainfall (GHR). The first approach in this verification is utilizing the Rapid Development Cumulus Area (RDCA) index, which is generated by RSO, for estimating cumulus life stage. The estimation of cumulus life stage will be approached by comparing between RDCA index and cumulus life stage estimated by radar. Based on the first trial of the comparison, we found the possibility of RDCA index to estimate the cumulus life stage, as we discovered that there is a good correlation between RDCA index and cumulus life stage in our study case. In the second approach, we compare the radar-estimated hydrometeor type with cloud top conditions retrieved from RSO in the earliest stage of rain. The three types of brightness temperature difference (BTD) using band no. 11, 13 and 15 of RSO data are used to know the cloud condition by distinguishing water and ice phases in a cloud in the baby-rain stage. In this first trial of one case analysis, we found a potential of utilization of RSO to estimate cloud phase in the early stage of cumulus cloud since there is a good spatial correlation between them.
