TRMM可視赤外観測装置(VIRS)とその利用

抄録

Visible-Infrared Scanner (VIRS) is a five-channel visible-infrared radiometer on board TRMM. The VIRS will serve as a background imager and will provide the cloud context. The VIRS is also to serve as a 'bridge' from TRMM rainfall estimates to estimates made with geostationary satellite using VIS/IR technique. Therefore, the TRMM rainfall estimates can be used as a calibration data for the geostationary infrared rainfall estimate which has been done for 20 years. In this report, we review the current usage of corresponding VIRS channels for rainfall estimation and extraction of other useful meteorological information such as water vapor, cloud properties etc. Some preliminary results using the actual VIRS/PR/TMI data are also presented. The ratio of ch 1/ch 2 shows good indicator for dense ice cloud which correspond well to rain identified by PR. The smaller values of brightness temperature difference between ch 3 and ch 4, and also ch 4 and ch 5 show reasonable correspondence to rain area identified by PR.