Identification of fog with NOAA AVHRR images

The authors attempted to identify fog using image-processing data from the US National Oceanic and Atmospheric Administration (NOAA) Advanced Very High Resolution Radiometer (AVHRR). AVHRR sensors measure radiation at visible, near-infrared, and infrared wavelengths. Attention is confined to daytime data from channel 1 (CH1), channel 3 (CH3), and channel 4 (CH4) for a detection range of λ=0.58~0.68 μm, λ=3.55~3.93 μm, and λ=10.5~11.5 μm, respectively. The authors have analyzed by image processing the data obtained from CH1, CH3, and CH4 by forming two- and three-dimensional histograms and enhancing them in color