|You might think that absolutely pure water would be perfectly clear and utterly transparent, but it's actually blue. Water absorbs some of the light that passes through it. It absorbs red light more than yellow, yellow more than green, and green more than blue. Only the deepest blue light can travel very far through water, so a large mass of water takes on a deep blue color.
What is ocean color?
The "color" of the ocean is determined by the interactions ofincident lightwith substances or particles present in the water. The most significant constituents are free-floatingphotosyntheticorganisms (phytoplankton) and inorganic particulates. Phytoplankton containchlorophyll, which absorbs light at blue and red wavelengths and transmits in the green. Particulate matter can reflect and absorb light, which reduces the clarity (light transmission) of the water. Substances dissolved in water can also affect its color.
What is ocean color data?
The phrase "ocean color data" refers to accurate measurements of light intensity at visible wavelengths. As ocean color data is related to the presence of the constituents described above, it may therefore be used to calculate the concentrations of material in surface ocean waters and the level of biological activity. Ocean color observations made from Earthorbitallow an oceanographic viewpoint that is impossible from ship or shore -- a global picture of biological activity in the world's oceans.