Diurnal variation of surface thermodynamic fields on the island of Hawaii

Abstract

On the windward site, the onset of upslope (downslope) flow in the morning (evening) is closely related to the thermal contrasts between the slope surface and the upstream air. After sunrise around 0600 HST, the onset of upslope flow occurs at approximately 0730 HST on the upper slopes where the virtual temperature first becomes warmer than the environment. In the early evening, the onset of downslope flow occurs just before sunset about 1900 HST in the windward lowland where the virtual temperature first drops below the environmental value. -from Authors