Using BRDFs for accurate albedo calculations and adjacency effect corrections

Conference · Sun Sep 01 04:00:00 EDT 1996

OSTI ID:378793

Borel, C C; Gerstl, S A.W.

In this paper the authors discuss two uses of BRDFs in remote sensing: (1) in determining the clear sky top of the atmosphere (TOA) albedo, (2) in quantifying the effect of the BRDF on the adjacency point-spread function and on atmospheric corrections. The TOA spectral albedo is an important parameter retrieved by the Multi-angle Imaging Spectro-Radiometer (MISR). Its accuracy depends mainly on how well one can model the surface BRDF for many different situations. The authors present results from an algorithm which matches several semi-empirical functions to the nine MISR measured BRFs that are then numerically integrated to yield the clear sky TOA spectral albedo in four spectral channels. They show that absolute accuracies in the albedo of better than 1% are possible for the visible and better than 2% in the near infrared channels. Using a simplified extensive radiosity model, the authors show that the shape of the adjacency point-spread function (PSF) depends on the underlying surface BRDFs. The adjacency point-spread function at a given offset (x,y) from the center pixel is given by the integral of transmission-weighted products of BRDF and scattering phase function along the line of sight.

• Research Organization: Los Alamos National Lab., NM (United States)
• Sponsoring Organization: National Aeronautics and Space Administration, Washington, DC (United States)
• DOE Contract Number: W-7405-ENG-36
• OSTI ID: 378793
• Report Number(s): LA-UR--96-2796; CONF-9609240--2; ON: DE96014620
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
ALBEDO
CALCULATION METHODS
INFRARED RADIATION
MATHEMATICAL MODELS
RADIOMETERS
REFLECTION
REMOTE SENSING
STRATOSPHERE
VISIBLE RADIATION