Properties of convectively induced turbulence over developing oceanic convection

Abstract

Convectively induced turbulence (CIT) is an aviation hazard that continues to be a forecasting challenge asoperational forecast models are too coarse to resolve turbulence affecting aircraft. In particular, little is knownabout tropical maritime CIT. In this study, a numerical simulation of a tropical oceanic CIT case where severeturbulence was encountered by a commercial aircraft is performed. The Richardson number (Ri), subgrid-scaleeddy dissipation rate (EDR), and second-order structure functions (SF) are used as diagnostics to determinewhich may be used for CIT related to developing and mature convection. Model-derived subgrid-scale EDRin past studies of midlatitude continental CIT was shown to be a good diagnostic of turbulence but underpredicted turbulence intensity and areal coverage in this tropical simulation. SF diagnosed turbulence withmoderate to severe intensity near convection and agreed most with observations. Further, SF were used todiagnose turbulence for developing convection. Results show that the areal coverage of turbulence associatedwith developing convection is less than mature convection. However, the intensity of turbulence in the vicinityof developing convection is greater than the turbulence intensity in the vicinity of mature convection highlighting developing convection as an additional concern to aviation.