Identifying the Deep-Inflow Mixing Features in Orographically-Locked Diurnal Convection

Abstract

Orographically-locked diurnal convection involves interactions between local circulation and the thermodynamic environment of convection. Here, the relationships of convective updraft structures over orographic precipitation hotspots and their upstream environment in the TaiwanVVM large-eddy simulations are analyzed for the occurrence of the orographic locking features. Strong convective updraft columns within heavily precipitating, organized systems exhibit a mass flux profile gradually increasing with height through a deep lower-tropospheric inflow layer. Enhanced convective development is associated with higher upstream moist static energy (MSE) transport through this deep-inflow layer via local circulation, augmenting the rain rate by 36% in precipitation hotspots. The simulations provide practical guidance for targeted observations within the most common deep-inflow path. Preliminary field measurements support the presence of high MSE transport within the deep-inflow layer when organized convection occurs at the hotspot. Orographically-locked convection facilitate both modeling and field campaign design to examine the general properties of active deep convection.