Observation of Albedo at the Surface of Pavement

Abstract

Albedo of the surface of pavement is closely related to behavior of the surface temperature of pavement. Therefore, it is an effective factor for a theoretical analysis of the surface temperature. The observation of albedo was made at the surface of a dense grade asphalt concrete pavement in Ebetsu-shi, Hokkaido during the period from November 5 to November 6, 1971.Two net radiometers were set up on the surface mentioned above, one for measurements of net radio fluxes and the other for upward radio fluxes both at the surface. Temperatures at the surface were measured with thermocouples. The observed data were discussed in connection with the accuracy of the observation and were used in the calculation of albedo at the surface.As a result, it was found that the albedo for short wave was 12.1% in case of dry surface, 7.4% wet surface, and the albedo for long wave was 1.5±1.0% in case of wet surface. The fact that for short wave the albedo at the dry surface is larger than at the wet surface agrees with the behavior of albedo as regards soil surface.