Coastal zone color scanner

The coastal zone color scanner (CZCS) was a multi-channel scanning radiometer aboard the Nimbus 7 satellite, predominately designed for water remote sensing.

The "color" of the ocean in CZCS images comes from substances in the water, particularly phytoplankton (microscopic, free-floating photosynthetic organisms), as well as inorganic particulates.

By recording images over a period of years, scientists also gained a better understanding of how the phytoplankton biomass changed over time; for instance, red tide blooms could be observed when they grew.

Raw data from the scanner were transmitted, at an average bit rate of 800 kbit/s, to the ground station, where they were saved on magnetic tape.

The archive was one of the first instances of a system that provided a visual preview ("browse") of images, which assisted in ordering data.

CZWS was the first satellite ocean color sensor, and after it stopped observing in 1986, there was a 10-year gap in records until Japan launched the Ocean Color Temperature Scanner (OCTS) in 1996, and the United States launched the Sea-viewing Wide Field-of-view Sensor (SeaWiFS) in 1997.

Current instruments that provide ocean color data include Aqua-MODIS, Copernicus Sentinel 3 Ocean and Land Colour Instrument (OLCI), and NOAA's Visible Infrared Imaging Radiometer Suite (VIIRS) on board the Joint Polar Satellite System (JPSS) satellites.

Ocean color around Tasmania (false color). Red and orange colors indicate high levels of phytoplankton.
The Global Biosphere – a composite of all 60,000 CZCS images plus three years of land vegetation data collected by the Advanced Very High Resolution Radiometer instrument.
An artist's rendering of the Nimbus satellites' design