Implementation of a double plume convection parameterization in the CIESM model and its impact on the modeled climate

A double plume convection parameterization is implemented in the Community Integrated Earth System Model (CIESM). The impact of the double plume convection scheme on the modeled climate is studied based on the 21-year CMIP (PiControl) simulation. The modeled climate using the double plume convection scheme is evaluated by comparing with that using the default deep and shallow convection schemes. Using the double plume scheme overall can generate realistic climate statistics. The scheme reduces the negative biases in model top net radiation fluxes in the low-latitude oceanic regions. Longwave cloud forcing (LWCF) is increased by the double plume convection scheme. The negative biases in LWCF in the low latitudes are reduced, while positive biases arise over the Maritime Continent and the tropical Indian ocean. Annual mean precipitation and seasonal variation of the Intertropical Convergence Zone is not sensitive to changes in convection parameterization. CIESM shows high skills in capturing the eastward propagation of Madden-Julian Oscillation (MJO), and the double plume convection scheme improves the variation of MJO precipitation. This study exhibits the stability and reasonableness of the double plume convection scheme for the CISEM coupled simulation. Collaborative parameter tuning is needed to further improve the energy budget for the double plume convection scheme.