Putting Together the Big Picture: Remote-sensing Observations of Ocean Color SPECIAL ISSUE – JGOFS

Observations of ocean color from space have been part of the U.S. JGOFS strategy for discerning temporal and spatial variations in upper-ocean productivity on the global scale since the first planning workshops for a U.S. global ocean flux program (National Academy of Sciences, 1984). From the start, remote measurements of near-surface chlorophyll a concentrations were envisaged as the major tool for extrapolating upper-ocean chemical and biological measurements in time and space and linking calculations of new and primary production with the flux of particulate material through the water column. In 1986, researchers at the U.S. National Aeronautics and Space Administration (NASA) Goddard Space Flight Center published the first monthly composite of images from the Nimbus-7 Coastal Zone Color Scanner (CZCS), an ocean color instrument that had been in orbit since 1978. These images showed basin-scale views of phytoplankton chlorophyll distributions for the first time (Esaias et al., 1986). These new images, coupled with the JGOFS requirement for satellite ocean-color measurements, rejuvenated interest at NASA and other space agencies in launching successors to the CZCS. CZCS stopped operating during 1986. By spring 1988, when the initial planning workshop for the international North Atlantic Bloom Experiment (NABE) was held, it was apparent that data from a new sensor would not be available for the first JGOFS field program, scheduled to begin in the North Atlantic in spring 1989. Because of launch delays and other technical problems, the next ocean-color instrument, the Seaviewing Wide Field-of-view Sensor (SeaWiFS), was not launched into space until August 1997. Thus satellite ocean-color observations were available only for the Antarctic Environment and Southern Ocean Process Study (AESOPS), the final U.S. JGOFS field program. Putting Together the Big Picture: Remote-sensing Observations of Ocean Color SPECIAL ISSUE – JGOFS