A relation between landsat digital numbers, surface reflectance, and the cosine of the solar zenith angle

Abstract A method for estimating the reflectance of ground sites from satellite radiance data is proposed and tested. The method uses the known ground reflectance from several sites and satellite data gathered over a wide range of solar zenith angles. The method was tested on each of 10 different Landsat images using 10 small sites in the Walker Lake, Nevada area. Plots of raw Landsat digital numbers (DNs) versus the cosine of the solar zenith angle (cos Z) for the the test areas are linear, and the average correlation coefficients of the data for Landsat bands 4, 5, 6, and 7 are 0.94, 0.93, 0.94, and 0.94, respectively. Ground reflectance values for the 10 sites are proportional to the slope of the DN versus cos Z relation at each site. The slope of the DN versus cos Z relation for seven additional sites in Nevada and California were used to estimate the ground reflectances of those sites. The estimates for nearby sites are in error by an average of 1.2% and more distant sites are in error by 5.1%. The method can successfully estimate the reflectance of sites outside the original scene, but extrapolation of the reflectance estimation equations to other areas may violate assumptions of atmospheric homogeneity.

[1]  E. L. Gray,et al.  Optical reflection properties of natural surfaces , 1965 .

[2]  R. Daubenmire.  Plant Geography: With Special Reference to North America , 1980 .

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

[4]  K. Kriebel,et al.  On the variability of the reflected radiation field due to differing distributions of the irradiation , 1975 .

[5]  H. W. Smedes,et al.  The mixture problem in computer mapping of terrain: Improved techniques for establishing spectral signatures, atmospheric path radiance, and transmittance , 1975 .

[6]  THE DISPLAY OF LANDSAT DATA AT LARGE SCALES BY MATRIX PRINTER , 1977 .

[7]  Alexander F. H. Goetz,et al.  DISCRIMINATION OF HYDROTHERMALLY ALTERED AND UNALTERED ROCKS IN VISIBLE AND NEAR INFRARED MULTISPECTRAL IMAGES , 1977 .

[8]  R. W. Dana.  Solar and atmospheric effects on satellite imagery derived from aircraft reflectance measurements , 1975 .

[9]  John A. Dutton,et al.  Albedo variations measured from an airplane over several types of surface , 1962 .

[10]  G. Ballew,et al.  A comparison of observed and model-predicted atmospheric perturbations on target radiances measured by ERTS: Part I-Observed data and analysis , 1975, 1975 IEEE Conference on Decision and Control including the 14th Symposium on Adaptive Processes.

[11]  Edward V. Ashburn,et al.  Spectral Diffuse Reflectance of Desert Surfaces , 1956 .

[12]  V. V. Salomonson,et al.  Anisotropic Solar Reflectance over White Sand, Snow and Stratus Clouds. , 1968 .