#sinlight

SUNGLINT

The “wine-dark sea” of Homer’s Aegean can only be understood by those who have immersed themselves in its rich translucence in the dark of night – a translucence like that of fine wine. Certainly in this wondrous photo by NASA, the sea is not “wine-dark” but seems a mix of colors of azure to blue to pearly turquoise. These colors are caused by a process of reflection given the name “sunglint.”

Sunglint is created when sunlight reflects off the sea at the same angle that a satellite sensor (or astronaut's eyes) views it. Because the sea is not a flat surface, but covered by minor waves, crossed by flowing currents, swirled by a mix of upwelling waters, its reflection is not seen as a uniform color to the viewing satellite or astronaut. Sunglint is the sea viewed as an irregular mirror surface, the reflection creating ghostly hues.

For scientists, these reflections reveal details of atmospheric circulation and what is, in this photo, atmospheric gravity waves downwind (south in this view) of the Aegean Islands. The large light-areas swirling in the region south of Crete’s high Psiloritis Mountains (reaching 2,456 m) are caused by the irregular flow of wind over the irregular topography, roughening and smoothing the sea surface leeward of the island. Sunglint can obscure other scientific phenomena like areas of phytoplankton and sediment load. But it can also help spot oil floating on the sea surface as the oily film smoothes the reflection locally, and dulls the Sunglint.

Now what, one wonders, would this reflection look like if a thin film floating on the sea’s surface was some of Homer’s wine, not oil?

Annie R