Noise reduction and atmospheric correction for coastal applications of landsat thematic mapper imagery

The Landsat Thematic Mapper (TM) has three visible bands centered at 485 nm , 560 nm, and 660 nm which can be used for ocean applications. This article presents a method for deriving the bottom albedo from the TM in coastal wa ters. Our study of historical TM images shows degradation of the sensor thr ough time. Pattern noise in the imagery in Bands 2 and 3 was analyzed and r emoved using a combination of Fourier filtering and edge-detection techniqu es. Noise was first examined over clear and deep nearby oceanic waters, and the filter algorithms developed there were applied to the entire image. To estimate water-leaving radiance from the satellite sensor, Rayleigh and ae rosol path radiance were removed. Radiance due to aerosol scattering was ca lculated for offshore pixels assuming a marine aerosol type, and it was rem oved as a constant from the entire scene. The TM sensor calibration was val idated by comparing water-leaving radiance values over the clear waters of the Florida current with known, normalized water-leaving radiance values. C orrections for water path radiance and water-column attenuation of bottom-r eflected radiance were made for regions of known depth, allowing the bottom albedo and vegetative pixel fraction to be determined for shallow reef are as in the Florida Keys. (C)Elsevier Science Inc., 1999.