Validation of a simple diagnostic relationship for downslope flows

Abstract

A simple conceptual view of downslope flows allows a derivation of a diagnostic relationship between the maximum depth of the flow, its speed, the slope angle and the cooling flux. This relationship is obtained considering that the turbulence cooling causing the air to flow downslope is essentially compensated by the warming by compression as the flow reaches higher pressure levels. The obtained relationship is consistent with the bulk heat budget for the along-slope flows, and its agreement with existing prognostic layer-averaged models is checked. Finally, the depth of the flow obtained from the diagnostic relationship is compared against the observational estimations of katabatic flows from two experimental campaigns.