Reflected irradiance indicatrices of natural surfaces and their effect on albedo.

The indicatrices of solar radiation reflected from characteristic natural surfaces were measured with a Nimbus Medium Resolution Radiometer (MRIR) 3 m above the ground. Results indicated that areas such as salt and alkali flats had only small deviations from isotropic reflections, while others such as sparsely vegetated areas had substantial deviations. The indicatrices were strongly dependent on the sun angle; thus a daily variation was found for most features. Typical indicatrices, normalized to nadir angle of zero degrees, are presented along with their impacts on measured albedo, which varies with solar angle. Our results can (1) improve surface albedo considerations using space-generated data, and (2) serve as a more realistic lower boundary condition for atmospheric transfer determinations based on space data.

[1]  T. H. Haar,et al.  Measurements of the Earth's Radiation Budget from Satellites During a Five-Year Period. Part I: Extended Time and Space Means , 1971 .

[2]  L. M. Shields,et al.  ALGA‐ AND LICHEN‐STABILIZED SURFACE CRUSTS AS SOIL NITROGEN SOURCES , 1957 .

[3]  P Koepke,et al.  Influence of measured reflection properties of vegetated surfaces on atmospheric radiance and its polarization. , 1978, Applied optics.

[4]  B. Hapke,et al.  PHOTOMETRIC STUDIES OF COMPLEX SURFACES, WITH APPLICATIONS TO THE MOON , 1963 .

[5]  Frank D. Eaton,et al.  Some Characteristics of the Albedo of Snow , 1975 .

[6]  W. R. Bandeen,et al.  Anisotropic reflectance characteristics of natural Earth surfaces. , 1970, Applied optics.

[7]  Edwin D. McKee,et al.  STRUCTURES OF DUNES AT WHITE SANDS NATIONAL MONUMENT, NEW MEXICO (AND A COMPARISON WITH STRUCTURES OF DUNES FROM OTHER SELECTED AREAS)1 , 1966 .

[8]  Kinsell L. Coulson,et al.  Effects of reflection properties of natural surfaces in aerial reconnaissance. , 1966, Applied optics.

[9]  The Luminous Directional Reflectance of Snow , 1953 .

[10]  W. Burt.  ALBEDO OVER WIND-ROUGHENED WATER , 1954 .

[11]  Thomas H. Vonder Haar,et al.  The annual radiation balance of the earth-atmosphere system during 1969-70 from Nimbus 3 measurements. , 1973 .

[12]  John T. Smith,et al.  Manual of color aerial photography , 1968 .

[13]  A. G. Mungall,et al.  The Luminous Directional Reflectance of Snow , 1952 .

[14]  C. Cox.  Statistics of the sea surface derived from sun glitter , 1954 .