Abstract
The slope wind circulation was investigated by a laboratory experiment using a temperaturecontrolled water tank, the bottom of which consists of a PLAIN and a SLOPE. The following results were obtained:
(1) A cellular convection occurs on the plain with the rise of the surface temperature of the plain and the slope, as was seen in the laboratory experiment on the land- and sea-breeze circulation (Mitsumoto et al., 1983). However, it does not occur on the slope. The flow along the slope has a smooth periodical variation. The thermal boundary layer on the slope is thinner than that on the plain. The phase of the temperature variation on the plain delays upward, while the phase on the slope is constant and the same as that of the surface temperature.
These results are explained using the solution of a simple linear theory corresponding to the case in which the surface temperature of an infinitely long slope varies periodically.
(2) The total flow circulation in the whole slope-plain system is quite complicated. The upslope flow constitutes a circulation with the height comparable to the slope height, while the downslope circulation is restricted in a lower region with a second circulation above it. The counter-flows to the main flows along the slope have a tendency to maintain their directions throughout one period, adapting themselves to the alternating stage by changing their roles in the total flow system. Such a conservation of the flow direction produces a residual flow in this laboratory model.
