Physics Parameterizations of Regional Climate Model RegCM4: Sensitivity to Convective Precipitation Schemes

Abstract

Cumulus convection is one of the most complex subgrid-scale process parameterized in climate models, which has major influence on the determination of the vertical distribution of energy, water and momentum. Numerous convective parameterizations have been developed and applied in global and regional climate models, with the results being very sensitive to the scheme selection. Thus, it is essential to study the sensitivity of climate models to the convective precipitation schemes. The examined regional climate model used in the study is RegCM4. Its spatial resolution is 25 x 25 km and different simulations were performed with changes in cumulus convection scheme and the corresponding closure assumptions. The selected domain of interest is the Mediterranean region. The simulations were forced by ERA-Interim data and cover the time period 1981-1990. The different simulated data were processed and the differences between the simulations were calculated, compared and mapped in order to examine the modifications that occur in precipitation from changes in convective precipitation scheme.