A numerical study of the diurnal variation of the low-level jet

Southerly flow over the eastern slope of the Rocky Mountains under the influence of a diurnal surface temperature wave was studied by numerical experiments and by analytic methods. The purpose of this study was to determine the interrelationships of various processes associated with the diurnal variation of the low level jet. Analytic solutions were obtained to diagnose the structure of the boundary layer of a rotating stratified fluid over a sloping surface undergoing heating and cooling. Results show that the thermal and momentum fields of this boundary layer are coupled; the cross isobar boundary layer flow is increased by the effect of a force along the direction of the terrain slope. Also, the vertical motion field is shown to be controlled by two mechanisms, Ekman pumping and buoyant pumping, respectively.