[A-AS03] Large-scale moisture and organized cloud systems

[AAS03-08] Up-scale Processes of Aggregated Convection

★Invited Papers

*Chien-Ming Wu¹, Fu-Sheng Kao¹ (1.Department of Atmospheric Sciences, National Taiwan University)

Keywords:cloud-resolving model, buoyancy structure, Gaussian convolution , Radiative-Convective Equilbrium

In this study, we use cloud-resolving simulations of aggregated convection with a slab ocean and a mock-Walker circulation setup to diagnose the upscale processes of aggregated convection. This diagnosis is performed using the vector vorticity equation in a cloud-resolving model (VVM). We apply a Gaussian convolution filter to the simulated data to determine the structures at the filtered scale (Psi~) and the eddy scale (Psi'). By diagnosing the partition between the eddy transport of moist static energy (MSE) flux and the filtered scale MSE transport, we identify the horizontal scale and the onset of aggregated convection. This is achieved when the filter scale accounts for the majority of the transport. Our results indicate that, with a sharp onset, the horizontal scale of aggregated convection can expand from 12 km to 192 km within three days. Conversely, with a weak onset, the upscale processes can take more than a week. We examine the buoyancy structure during aggregation to understand this discrepancy. The diagnostic approaches developed in this study quantify the moisture convection feedbacks and can be applied to other types of aggregation simulations (RCEMIP) or global storm-resolving simulations (DYAMOND).