Ocean Colour Radiometry: Early Successes and a Look Towards the Future

Satellite ocean colour radiometry (OCR) provides ocean scientists with their only time-dependent view of indices related to ecological and biogeochemical processes at regional to global scales. Beginning with the launch of NASA’s Coastal Zone Color Scanner (CZCS) in 1978, imagery from multiple satellite sensors has had a major impact on ocean science and helped establish the importance of ocean biogeochemistry to the major element cycles of the Earth system. OCR is being increasingly used in applications related to societal benefits. Early accomplishments include: improved methods and more accurate calculations of net primary production in the ocean at regional to global scales, including estimates of the relative contributions of land and ocean to net primary production of the biosphere; better understanding of variability of phytoplankton biomass and productivity at regional to global scales and at daily to interannual time scales; better understanding of seasonal phytoplankton dynamics at regional and global scales; better understanding of the impact of major ENSO events and other sources of interannual variability on ocean net primary production and its spatial variations around the globe; intriguing evidence that phytoplankton biomass in the ocean, particularly in the oligotrophic waters in the center of the ocean basins, may be undergoing long term changes; better understanding of the importance of mesoscale mixing processes (eddies, planetary waves) on the distribution of phytoplankton biomass; and initial successes for using OCR imagery to improve fishing efficiency, track harmful algal blooms, provide potential tools for fisheries management, provide products related to water quality assessment and other applications of benefit to society.