208
W. Alpers et al.
Fig. 11.1 Photograph taken from the space shuttle Challenger at 12:02:55 UTC on 7 October 1984
(STS 41-G mission) by a handheld camera showing sea surface signatures of a cyclonic eddy in the
Mediterranean Sea adjacent to the Egyptian coast. The center point of the photograph is at 31.5
◦ N,
27.0
◦ E. The eddy with a diameter of approximately 35 km lies in inner sunglint region, where the
lines of reduced surface roughness (caused by surface films) are imaged bright
point on the water surface. The size and shape of the sunglint pattern depends on
the probability distribution of the slopes of the facets caused by the sea surface
roughness, the direction of incident sunlight and the viewing direction of the sensor
(Cox and Munk 1954; Jackson and Alpers 2010). Satellite optical sensors with spatial
resolutions of meters to hundreds of meters do not see the small individual glittering
facets, but rather averages over all facets that are contained within a resolution cell.
Thus differences in the sea surface roughness in and around the sunglint region
manifest themselves as variations in the image brightness.
On the photographs shown in Figs. 11.1, 11.2 and 11.3, the change of the sea
surface roughness is caused by surface films, which are entrained in the eddy’s
W. Alpers et al.
Fig. 11.1 Photograph taken from the space shuttle Challenger at 12:02:55 UTC on 7 October 1984
(STS 41-G mission) by a handheld camera showing sea surface signatures of a cyclonic eddy in the
Mediterranean Sea adjacent to the Egyptian coast. The center point of the photograph is at 31.5
◦ N,
27.0
◦ E. The eddy with a diameter of approximately 35 km lies in inner sunglint region, where the
lines of reduced surface roughness (caused by surface films) are imaged bright
point on the water surface. The size and shape of the sunglint pattern depends on
the probability distribution of the slopes of the facets caused by the sea surface
roughness, the direction of incident sunlight and the viewing direction of the sensor
(Cox and Munk 1954; Jackson and Alpers 2010). Satellite optical sensors with spatial
resolutions of meters to hundreds of meters do not see the small individual glittering
facets, but rather averages over all facets that are contained within a resolution cell.
Thus differences in the sea surface roughness in and around the sunglint region
manifest themselves as variations in the image brightness.
On the photographs shown in Figs. 11.1, 11.2 and 11.3, the change of the sea
surface roughness is caused by surface films, which are entrained in the eddy’s