Entrainment, Convective Heating and Organized Convection

 

Author

Da Yang — Lawrence Berkeley National Laboratory

Category

Convective clouds, including aerosol interactions

Description

Organized convection is ubiquitous in the tropical atmosphere and can produce intense precipitation. Moisture-entrainment feedback is considered as a key process to the development of convective organization: moist environment favors deep convection, which further moistens the atmosphere. Here we show that convective organization can still emerge, and that its strength remains almost unchanged when this entrainment-moisture feedback is disabled by artificially removing moisture anomalies in cloud-resolving simulations. In this “mechanism-denial” simulation, we find that convection heats the warm part of the atmosphere, generating available potential energy (APE) in the planetary boundary layer and leading to organized convection. We refer to this effect as convective heating - overturning circulation (CHOC) feedback. Implications on convection parameterization will also be discussed.