Recently new algorithm of locating cumulonimbus (Cb) has been developed using 'negative' difference between brightness temperatures of infrared and water vapour channel. Cb has a direct relation to typhoon intensity.

In order to use for estimation of typhoon intensity, brightness temperature difference (BTD) between infrared and water vapour channels of GMS was compared with rain intensity of TRMM PR, and BTD was validated within typhoons.

In the cases of Typhoon Rex and Typhoon Virgil, it was investigated that BTD below 0K qualitatively agreed with Cb detected by PR. Then grids in PR dataset were interpolated to coincide with those of GMS. The brightness temperature of GMS was compared with rain intensity of PR grid by grid. From this comparison, it was found quantitatively that BTD from -1K to 1K corresponds to convective rain more precisely.

It can be concluded that Cb area is selected effectively in typhoon using this BTD technique. So this technique is a very useful tool for objective estimation of typhoon intensity.