Physical Model of Diurnal Heating in the Vicinity of a Two-Dimensional Ridge

Abstract

Abstract Laboratory experiments were conducted to simulate the diurnal heating-cooling cycle in the vicinity of a ridge of constant cross section. In the model the fluid is a water solution stratified with salt to simulate the background stratification of the atmosphere. The flow is driven by recirculating water of a controlled temperature beneath the model; the model surface temperature is thus varied in a specified way to simulate the surface heating by solar insolation during the daytime hours and surface cooling by radiation during the nighttime. The pertinent similarity parameters are shown to be Gc, for daytime convective flow and Gd for nocturnal flow; here Gc = Hb/Hc, Gd = Hb/Hd, where Hb, is the mountain height, Hc the neutral buoyancy height of free convection. and Hd the characteristic thickness of the nighttime drainage flow. The model demonstrates some of the principal features of thermally driven mountain circulations, including daytime upslope winds and nocturnal downslope drainage flows. T...