July 3, 2014
If you look often at satellite images or astronaut photography, you have actually most likely seen intense spots of light that can ensure bodies of water gleam with uncommon color. (If not, take a look at these examples in the waters around Cape Cod and the Lesser Antilles, in addition to rivers in Brazil.) That gleam is brought on by sunglint, an optical phenomenon that takes place when sunshine shows off the surface area of water at the exact 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.
Sunglint
The mirror-like reflection of the Sun off a water surface area in a satellite image. If the ocean were as smooth as a mirror, a series of almost best reflections of the Sun would appear in a line along the track of the satellite’s orbit. Because the ocean is never ever completely smooth or calm, nevertheless, the Sun’s reflection gets blurred as the light is spread in all instructions by waves. The blurred reflection provides the ocean surface area a rinsed look– the sunglint area.
If bodies of water were completely smooth, a series of almost best reflections of the Sun would appear in a line along the track of the satellite’s orbit. In truth, water surface areas are irregular and frequently in movement due to waves and currents, so the sunshine gets spread in lots of instructions and leaves fuzzy streaks of light in the swaths of satellite information. For circumstances, observe the strips of sunglint in the mosaic listed below. All of the information was gathered by the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA‘s Aqua satellite on July 3, 2014.
The mix of sunglint, wind patterns, and island shapes around Crete and the Aegean islands produced an especially incredible scene that day. (See the image at the top of this page.) Although sunglint rinses lots of functions, it likewise exposes information about the water and climatic blood circulation that are generally concealed. In this case, sunglint exposed wakes brought on by north and northwest winds that roughed up and smoothed the water surface area behind Crete and the other islands.
The islands develop a sort of wind shadow– obstructing, slowing, and rerouting air circulation. That wind, or absence of it, accumulate waves and choppy water in some locations and relaxes the water surface area in others, altering how light is shown. In addition, sunglint exposed what seem climatic gravity waves downwind of much of the Aegean Islands.
July 3, 2014
While sunglint frequently produces visually-stunning images, the phenomenon can develop issues for remote noticing researchers due to the fact that it obscures functions that are generally noticeable. This is especially real for oceanographers who utilize satellites to study phytoplankton and ocean color. As an outcome, scientists have actually established a number of approaches to evaluate sunglint-contaminated images out of information archives.
Despite the obstacles presented by sunglint, the phenomenon does use some distinct clinical chances. It makes it much easier, for example, to spot oil on the water surface area, whether it is from natural oil seeps or human-caused oil spills. This is due to the fact that a layer of oil smooths water surface areas.
NASA images courtesy LANCE/EOSDIS MODIS Rapid Response Team, GSFC.
