Satellite-to-In Situ Ocean Measurements

What is Ocean Color?
The "color" of the ocean is determined by the interactions of incident light with substances or particles present in the water. The most significant constituents are free-floating photosynthetic organisms (phytoplankton) and inorganic particulates. Phytoplankton contain chlorophyll, 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.

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 Earth orbit allow an oceanographic viewpoint that is impossible from ship or shore -- a global picture of biological activity in the world's oceans.

Instruments in this photo are being used to collect vertical light field profiles for ocean radiance and irradiance measurements for use in algorithms for marine optical properties and pigments (bio-optical algorithms) and for comparison with the satellite derived products, i.e., product validation.

Oceanographers at NASA Goddard Space Flight Center conduct studies in ocean color calibration and validation activities in the oceans.  To find out more about NASA's Ocean Color Research and Data,  visit: http://oceancolor.gsfc.nasa.gov/
Photo courtesy of Stan Hooker (NASA GSFC)