Effects of solar zenith angle on forest canopy albedos calculated with a geometric-optical model. (Reannouncement with new availability information)

Technical Report · Fri May 29 00:00:00 EDT 1992

OSTI ID:177483

Schaaf, C B; Ki, X; Strahler, A H

The Bidirectional Reflectance Distribution Function (BRDF) provided by the Li-Strahler geometric-optical forest canopy model has been integrated to provide instaneous hemispherical reflectances of vegetated surfaces. Given the anisotropy of canopied surfaces, the sensitivity of these spectral albedos to the illumination angle of the sun was suspect and therefore required testing. A variety of simulated canopies (conifer, savanna and shrub) were modeled with varying solar angles. In all cases, the surface albedo gradually decreased with increasing solar zenith angle. Such sensitivity to solar position simplifies the realistic modeling of surface albedos for energy balance studies.

• Research Organization: Phillips Lab., Hanscom AFB, MA (United States)
• OSTI ID: 177483
• Report Number(s): AD-A-256680/0/XAB; PL-TR-92-2224; TRN: 60110840
• Resource Relation: Other Information: PBD: 29 May 1992
• Country of Publication: United States
• Language: English

Related Subjects

09 BIOMASS FUELS
FORESTS
AERIAL SURVEYING
CANOPIES
ALBEDO
ANISOTROPY
SPECTRAL REFLECTANCE
SUN