A treatment for the stratocumulus-to-cumulus transition in GCMs

摘要: Numerical models of climate have great difficulties with the simulation marine low clouds in subtropical Pacific and Atlantic Oceans. It has been especially difficult to reproduce observed geographical distributions different cloud regimes those regions. The present study discusses mechanisms proposed previous works for changing one regime into another. One criterion is based on theory stratocumulus destruction through top entrainment instability due buoyancy reversal—situations which mixture two air parcels becomes denser than either original evaporation water. Another existence decoupling boundary layer. When decoupled, changes another these can still exist together cumulus. In a LES study, authors suggested that combination criteria be used diagnose whether, at location, corresponds well-mixed regime, shallow cumulus or transitional where layer decoupled. concept tested framework an atmospheric general circulation model (GCM). found several outstanding features disagreement between observation interpreted as misrepresentations by GCM. A novel switching among alleviate effects misrepresentations.