资源环境科技发展态势分析平台

The moisture-entrainment-convection (MEC) feedback posits that a moist environment favors deep convection, which further moistens the atmosphere through its associated circulation and detrainment. The MEC feedback has been proposed to be crucial to spontaneous convective aggregation. Here we test this hypothesis by performing minimal cloud-resolving simulations, without the buoyancy effect due to water vapor, evaporation of rain, or radiative and surface-flux feedbacks. Convection can self-aggregate in this minimal simulation, in which the MEC feedback is active. We then switch off this feedback by relaxing moisture to its horizontal mean over a time scale of 3 hr. Convection still self-aggregates in this mechanism-denial experiment, suggesting that the MEC feedback is not essential to self-aggregation. We further show that convective heating coincides with positive temperature anomalies, generating available potential energy. Therefore, we propose that this convective heating-overturning circulation feedback can lead to spontaneous development of large-scale circulations.