We have also performed a preliminary analysis of heating and moistening rate. The greater part of the water vapor that was removed from the air appeared to be converted to rain droplet by convection process. The amount of the cloud water that was detrained in the middle of the troposphere seemed to be too small. These facts suggest that the dry bias is due to deficiencies in convection process.
We are currently comparing JMA-GSM with JMA-NHM in the tropics, aiming to improve its capability of simulating cumulus convection. The JMA-NHM is a non-hydrostatic model. It is the operational limited-area NWP model in Japan. The comparison is going to reveal deficiencies in parameterizations of JMA-GSM.
In the presentation, we show the results of the comparison between JMA-GSM and JMA-NHM, and then make some discussions of remedies for the deficiencies, after briefly introducing the dry bias. The prototype of improved parameterization will also be shown.