SUN GLITTER IN SPOT IMAGES AND THE VISIBILITY OF OCEANIC PHENOMENA

摘要

In this paper we study the effect of sun glitter on the imaging of the ocean by optical satellite sensors. Sun glitter is the specular reflection of sunlight by suitably tilted facets of the water surface into the sensor, therefore the intensity of sun glitter depends on the ocean surface roughness and on the imaging geometry (sun's position, sensor's viewing direction). It is the effect of sun glitter that makes oceanic phenomena like surface slicks or current gradients visible on images from, e.g., the SPOT (Satellite Pour l'Observation de la Terre) or Landsat satellites. The relation between surface roughness, imaging geometry and sun glitter is non-trivial and knowledge of it is relevant for correctly interpreting optical satellite images of the ocean.