User Manual - pancroma

Q cal = Quantized and calibrated standard product pixel values (DN)TOA reflectance with a correction for the sun angle is:ρλ = ρλ ' / cos(θ SZ ), where:ρλ = TOA planetary reflectanceθ SE = Local sun elevation angle. The scene center sun elevation angle indegrees is provided in the metadata (SUN_ELEVATION).θ SZ = Local solar zenith angle; θ SZ = 90° - θ SEPANCROMA TM has a utility for converting Landsat 8, 16-bit band file DNs to TOAreflectances. The procedure for carrying out such a conversion is similar to thatdescribed for converting Landsat 7 bands as described above.Conversions must be made one Landsat 8 band file at a time. Open a band fileby selecting ‘File’ | ‘Open’. Then select ‘PreProcess’ | ‘Compute RadiometricCorrections’ | ‘Compute Landsat 8 TOA Reflectance’. The TOA ReflectanceData Form will become visible. This form will ask you to input the Solar ElevationAngle from the metadata file that accompanies each Landsat 8 scene.Note that unlike Landsat 7, the conversion coefficients are the same for eachLandsat 8 band so it is not necessary to enter the band number. In addition, theconversion does not use the sun-earth distance (although this parameter is listedin the metadata).Landsat 8 Top of Atmosphere RadianceOLI and TIRS band data can be converted to TOA spectral radiance using theradiance rescaling factors provided in the metadata file:L λ = M L Q cal + A L where:L λ = TOA spectral radiance (Watts/( m2 * srad * µm))M L = Band-specific multiplicative rescaling factor from the metadata(RADIANCE_MULT_BAND_x, where x is the band number)A L = Band-specific additive rescaling factor from the metadata(RADIANCE_ADD_BAND_x, where x is the band number)189