.jpg/2000px-Blue_ocean_wave_(Unsplash).jpg)
Community hub
Recent from talks
Knowledge base stats:
Talk channels stats:
Members stats:
Ocean color
Ocean color is the branch of ocean optics that specifically studies the color of the water and information that can be gained from looking at variations in color. The color of the ocean, while mainly blue, actually varies from blue to green or even yellow, brown or red in some cases. This field of study developed alongside water remote sensing, so it is focused mainly on how color is measured by instruments (like the sensors on satellites and airplanes).
Most of the ocean is blue in color, but in some places the ocean is blue-green, green, or even yellow to brown. Blue ocean color is a result of several factors. First, water preferentially absorbs red light, which means that blue light remains and is reflected back out of the water. Red light is most easily absorbed and thus does not reach great depths, usually to less than 50 meters (164 ft). Blue light, in comparison, can penetrate up to 200 meters (656 ft). Second, water molecules and very tiny particles in ocean water preferentially scatter blue light more than light of other colors. Blue light scattering by water and tiny particles happens even in the very clearest ocean water, and is similar to blue light scattering in the sky.
The main substances that affect the color of the ocean include dissolved organic matter, living phytoplankton with chlorophyll pigments, and non-living particles like marine snow and mineral sediments. Chlorophyll can be measured by satellite observations and serves as a proxy for ocean productivity (marine primary productivity) in surface waters. In long term composite satellite images, regions with high ocean productivity show up in yellow and green colors because they contain more (green) phytoplankton, whereas areas of low productivity show up in blue.
Ocean color depends on how light interacts with the materials in the water. When light enters water, it can either be absorbed (light gets used up, the water gets "darker"), scattered (light gets bounced around in different directions, the water remains "bright"), or a combination of both. How underwater absorption and scattering vary spectrally, or across the spectrum of visible to infrared light energy (about 400 nm to 2000 nm wavelengths) determines what "color" the water will appear to a sensor.
Most of the world's oceans appear blue because the light leaving water is brightest (has the highest reflectance value) in the blue part of the visible light spectrum. Nearer to land, coastal waters often appear green. Green waters appear this way because algae and dissolved substances are absorbing light in the blue and red portions of the spectrum.
The reason that open-ocean waters appear blue is that they are very clear, somewhat similar to pure water, and have few materials present or very tiny particles only. Pure water absorbs red light with depth. As red light is absorbed, blue light remains. Large quantities of pure water appear blue (even in a white-bottom swimming pool or white-painted bucket). The substances that are present in blue-colored open ocean waters are often very tiny particles which scatter light, scattering light especially strongly in the blue wavelengths. Light scattering in blue water is similar to the scattering in the atmosphere which makes the sky appear blue (called Rayleigh scattering). Some blue-colored clear water lakes appear blue for these same reasons, like Lake Tahoe in the United States.
Microscopic marine algae, called phytoplankton, absorb light in the blue and red wavelengths, due to their specific pigments like chlorophyll-a. Accordingly, with more and more phytoplankton in the water, the color of the water shifts toward the green part of the spectrum.
The most widespread light-absorbing substance in the oceans is chlorophyll pigment, which phytoplankton use to produce carbon by photosynthesis. Chlorophyll, a green pigment, makes phytoplankton preferentially absorb the red and blue portions of the light spectrum . As blue and red light are absorbed, green light remains. Ocean regions with high concentrations of phytoplankton have shades of blue-to-green water depending on the amount and type of the phytoplankton.
Hub AI
Ocean color AI simulator
(@Ocean color_simulator)
Ocean color
Ocean color is the branch of ocean optics that specifically studies the color of the water and information that can be gained from looking at variations in color. The color of the ocean, while mainly blue, actually varies from blue to green or even yellow, brown or red in some cases. This field of study developed alongside water remote sensing, so it is focused mainly on how color is measured by instruments (like the sensors on satellites and airplanes).
Most of the ocean is blue in color, but in some places the ocean is blue-green, green, or even yellow to brown. Blue ocean color is a result of several factors. First, water preferentially absorbs red light, which means that blue light remains and is reflected back out of the water. Red light is most easily absorbed and thus does not reach great depths, usually to less than 50 meters (164 ft). Blue light, in comparison, can penetrate up to 200 meters (656 ft). Second, water molecules and very tiny particles in ocean water preferentially scatter blue light more than light of other colors. Blue light scattering by water and tiny particles happens even in the very clearest ocean water, and is similar to blue light scattering in the sky.
The main substances that affect the color of the ocean include dissolved organic matter, living phytoplankton with chlorophyll pigments, and non-living particles like marine snow and mineral sediments. Chlorophyll can be measured by satellite observations and serves as a proxy for ocean productivity (marine primary productivity) in surface waters. In long term composite satellite images, regions with high ocean productivity show up in yellow and green colors because they contain more (green) phytoplankton, whereas areas of low productivity show up in blue.
Ocean color depends on how light interacts with the materials in the water. When light enters water, it can either be absorbed (light gets used up, the water gets "darker"), scattered (light gets bounced around in different directions, the water remains "bright"), or a combination of both. How underwater absorption and scattering vary spectrally, or across the spectrum of visible to infrared light energy (about 400 nm to 2000 nm wavelengths) determines what "color" the water will appear to a sensor.
Most of the world's oceans appear blue because the light leaving water is brightest (has the highest reflectance value) in the blue part of the visible light spectrum. Nearer to land, coastal waters often appear green. Green waters appear this way because algae and dissolved substances are absorbing light in the blue and red portions of the spectrum.
The reason that open-ocean waters appear blue is that they are very clear, somewhat similar to pure water, and have few materials present or very tiny particles only. Pure water absorbs red light with depth. As red light is absorbed, blue light remains. Large quantities of pure water appear blue (even in a white-bottom swimming pool or white-painted bucket). The substances that are present in blue-colored open ocean waters are often very tiny particles which scatter light, scattering light especially strongly in the blue wavelengths. Light scattering in blue water is similar to the scattering in the atmosphere which makes the sky appear blue (called Rayleigh scattering). Some blue-colored clear water lakes appear blue for these same reasons, like Lake Tahoe in the United States.
Microscopic marine algae, called phytoplankton, absorb light in the blue and red wavelengths, due to their specific pigments like chlorophyll-a. Accordingly, with more and more phytoplankton in the water, the color of the water shifts toward the green part of the spectrum.
The most widespread light-absorbing substance in the oceans is chlorophyll pigment, which phytoplankton use to produce carbon by photosynthesis. Chlorophyll, a green pigment, makes phytoplankton preferentially absorb the red and blue portions of the light spectrum . As blue and red light are absorbed, green light remains. Ocean regions with high concentrations of phytoplankton have shades of blue-to-green water depending on the amount and type of the phytoplankton.