The albedo of Tottori sand dune was measured with a solarimeter (Eko MS-62) and recorded by a data logger Solac-III (Eko). The soil water content (g/g) was measured at various depths at 9:00 a.m. every day. The relationships of albedo with soil water content and solar elevation were determined.
The albedo changes with soil water content at the surface and at individual depths by two and three steps, respectively. The albedo decreased linearly with increasing surface soil water content over a small range. Outside that range, the albedo was essentially constant. The albedo appeared to be related strongly to solar elevation in the afternoon on clear days (transmissivity more than 0.55) when the surface soil water content was less than 0.005g/g at 9:00. This relationship did not exist in the forenoon period due to dew condensation on the sand surface at night. However, the daily distribution of albedo appears to be approximately symmetrical about solar noon in response to solar elevation effects if the soil water content at sunrise is less than 0.005g/g.