April 19, 2024

The Science of Sunglint

Sunglint
The mirror-like reflection of the Sun off a water surface in a satellite image. If the ocean were as smooth as a mirror, a sequence of almost best reflections of the Sun would appear in a line along the track of the satellites orbit.

If bodies of water were perfectly smooth, a series of nearly perfect reflections of the Sun would appear in a line along the track of the satellites orbit. In reality, water surface areas are irregular and frequently in movement due to waves and currents, so the sunlight gets scattered in numerous directions and leaves blurry streaks of light in the swaths of satellite information. For circumstances, observe the strips of sunglint in the mosaic below. All of the information was gathered by the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASAs Aqua satellite on July 3, 2014

That gleam is triggered by sunglint, an optical phenomenon that occurs when sunlight reflects off the surface area of water at the exact same angle that a satellite sensing unit sees it. The mirror-like reflection of the Sun off a water surface area in a satellite image. If bodies of water were completely smooth, a sequence of nearly perfect reflections of the Sun would appear in a line along the track of the satellites orbit. In reality, water surfaces are irregular and often in movement due to currents and waves, so the sunshine gets spread in many instructions and leaves blurry streaks of light in the swaths of satellite data. That wind, or absence of it, stacks up waves and choppy water in some locations and calms the water surface area in others, altering how light is reflected.

The mix of sunglint, wind patterns, and island shapes around Crete and the Aegean islands made for a particularly magnificent scene that day. (See the image at the top of this page.) Sunglint cleans out many functions, it also exposes information about the water and climatic circulation that are normally concealed. In this case, sunglint exposed wakes brought on by north and northwest winds that smoothed the water and roughened surface behind Crete and the other islands.
The islands develop a sort of wind shadow– obstructing, slowing, and redirecting air flow. That wind, or lack of it, piles up waves and choppy water in some places and soothes the water surface in others, altering how light is reflected. In addition, sunglint revealed what appear to be atmospheric gravity waves downwind of a number of the Aegean Islands.
July 3, 2014.
While sunglint typically produces visually-stunning images, the phenomenon can produce problems for remote sensing scientists because it obscures features that are usually visible. This is especially real for oceanographers who utilize satellites to study phytoplankton and ocean color. As an outcome, researchers have established numerous approaches to screen sunglint-contaminated imagery out of information archives.
Despite the obstacles positioned by sunglint, the phenomenon does use some special scientific chances. It makes it simpler, for circumstances, to find oil on the water surface, whether it is from natural oil seeps or human-caused oil spills. This is since a layer of oil smooths water surfaces.
NASA images courtesy LANCE/EOSDIS MODIS Rapid Response Team, GSFC.

July 3, 2014
That gleam is caused by sunglint, an optical phenomenon that happens when sunlight reflects off the surface of water at the same angle that a satellite sensing unit sees it. The result is a mirror-like specular reflection of sunshine off the water and back at the satellite sensing unit or astronaut.