Maltese Front Variability from Satellite Observations Based on AutomatedDetection

摘要

Maltese Front location statistics are obtained from multi-channel sea-surfacetemperature (MCSST) images, derived from Advanced Very High Resolution Radiometer (AvHRR) observations of the Mediterranean Sea during 3 March-27 September 1993. The statistics are based on semi-automated determinations of the Front's sea-surface temperature surface expression. Expert analyses from the Naval Oceanographic Office give an accuracy check. Expert techniques are largely manual, labor-intensive, subjective, and skill-dependent. A mathematical morphology-based method successfully delineates the Front; it finds the temperature gradients most likely to be the Front's and presents the corresponding segmentations to the operator. The method was developed to find stars in astronomical images, and has successfully analyzed solar magnetograms and satellite Gulf Stream images. Rings, fronts, and sunspots are not star-like, but simple pre-processing adapts the technique to these problem domains. The Maltese Front's thermal gradients are 5-10 times weaker than the Gulf Stream North Wall's, yet the method produces useful results. (AN).