Use of the NOAA-2 digitized satellite data for diagnosing marine fog in the North Pacific Ocean area

Abstract

Digital NOAA-2 visual and daytime infrared satellite data and marine surface synoptic reports, North Pacific Ocean, July 1973, are computer processed and diagnosed in an attempt to develop a scheme for identifying fog over open ocean areas as a function of satellite information only. Using approximately 3250 ship observations as ground-truth data, present and past weather, visibility, and cloud cover and type, were sorted into eleven categories and related to the satellite data observed within two hours of the ship report. Critical visual (brightness) and infrared (temperature) count values, separately and in combination, are specified for the purpose of discriminating fog from no-fog marine areas. Satellite count-value distributions for select categories are illustrated by histograms; the relative accuracies in separating fog from no fog as a function of visual and infrared count values are shown by skill-score analyses.