Shiptrack database analysis

Abstract

The radiative characteristics of collected commercial and Navy ship tracks are described through an analysis of AVHRR (Advanced Very High Resolution Radiometer) satellite imagery. The analysis is conducted in a format to show the usefulness of a database approach to processing large amounts of ship track data. 12 cases are analyzed, 9 commercial ship tracks and 3 Navy ship tracks. Satellite imagery for the above 12 cases was collected during the summer months of 1993 off the western coast of the United States. 306 Navy ship reports are associated with 55 satellite images. This data subset was subdivided and cross- referenced to provide statistical data on Navy track formation when a given report was under favorable track formation conditions. Reflectance signatures of the collected tracks show an increase through the first few hours of track formation. The emittance values of the tracks collected from night-time satellite imagery showed the expected decrease as droplet radius decreases. Nuclear powered vessels showed no evidence of track formation. The utility of database analysis for large datasets of observed ship tracks was demonstrated to be a viable method for future analysis of the 4000+ observed ship tracks in the collected imagery.