Can an Adapted Betts-Miller Scheme Improve the Representation of Atmospheric Variability?

The parameterisation of moist convection is a necessary task for global circulation models to determine grid scale precipitation. However, there are many elements of cumulus parameterisation that are inconsistent with observations. Of particular interest to this study is the tropical intraseasonal variability and the interactions with global circulation. It is hoped that by introducing a new moisture tendency equation into the simplified Betts-Miller scheme, that we can gain new insight into atmospheric variability. The new tendency equation is sensitive to both the buoyancy and relative humidity of the environment. This scheme has the potential to be more flexible than adjusting to a fixed relative humidity profile, as in the case for the simplified Betts-Miller scheme. The GFDL moist aqua-planet model will be used to assess the new scheme, as this model facilitates our investigation in a simplified environment. Validation of the new scheme will be presented, together with a comparison to the Betts-Miller and simplified Betts-Miller schemes.