A modified cumulus convection parametrisation scheme is presented.This scheme computes the mass of air transported upward in a cumulus cellusing conservation of moisture and a detailed distribution of convectiveprecipitation provided by a reanalysis dataset. The representation ofvertical transport within the scheme includes entrainment and detrainmentprocesses in convective updrafts and downdrafts. Output from the proposedparametrisation scheme is employed in the National Institute forEnvironmental Studies (NIES) global chemical transport model driven byJRA-25/JCDAS reanalysis. The simulated convective precipitation rate andmass fluxes are compared with observations and reanalysis data. A simulationof the short-lived tracer Rn is used to further evaluate theperformance of the cumulus convection scheme. Simulated distributions ofRn are evaluated against observations at the surface and in the freetroposphere, and compared with output from models that participatedin the TransCom-CH Transport Model Intercomparison. From thiscomparison, we demonstrate that the proposed convective scheme in general isconsistent with observed and modeled results.
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