Investigation of Relationship between RDCA Index Using Himawari-8 Data and Radar Estimated Hydrometeor Type aloft Considering the Stage of Cumulus Cloud

Abstract

The objective of this study is to investigate the relationship between RDCA index retrieved from Rapid Scan Observation (RSO) of Himawari-8 data with hydrometeor type retrieved from polarimetric radar data by considering the stage of cumulus cloud stage. The cumulus cloud life stage is retrieved from the comparison of radar-estimated cumulus life stages such as development, early mature, mature late and dissipation stage with RDCA index. We investigate seven cases of comparison of time variation between RDCA index and radar-estimated cumulus life stage. From the seven cases, we found that three cases of them have good time correlation and four others are in poor time correlation. We choose one case among the good time correlation cases and one case among the poor time correlation to investigate the relationship between RDCA index and radar-estimated hydrometeor type. We found that the poor time correlation might be due to the overestimation of RDCA index caused by the occurrence of upper-level cloud. Based on the good cases we found that there is a possibility to utilize the RDCA index to estimate the cumulus life stage.