The representation of cumulus convection in a 20-km-mesh global hydrostatic model

We are investigating the representation of cumulus convection in JMA-GSM, by comparing with satellite observations and a non-hydrostatic limited area model. The JMA-GSM is a global hydrostatic model. It is the operational global NWP model in Japan. The spatial resolution was recently upgraded from 60-km-mesh to 20-km-mesh. According to the preliminary results of the 60-km-mesh model, the model represents precipitation over larger areas than the observed and this fact seems to cause the dry bias in the middle of the troposphere.

We are currently evaluating 20-km-mesh version of JMA-GSM. In the presentation, we show the characteristics in the representation of cumulus convection in the 20-km-mesh model.