IOC Workshop on Ocean Colour Data Requirements and Utilization, Sidney, Canada 21-22 September 1995.

Ocean colour data is essential for monitoring and fostering our understanding of important ocean biological processes. Adequate data pertaining to ocean biological processes is extremely difficult to obtain due to the vast area of the ocean (over 70 % of the earth’s area) and to the logistical difficulties of shipboard sampling. Satellite views of ocean colour are our only chance for gaining an overall view of the state of ocean biology at any given time. Ocean colour data is also the most practical way to develop the time-series data that will allow us to separate natural variability in ocean biological processes from secular changes. Ocean colour data will allow us to monitor at a minimum such important areas as: biogeochemical cycles, direct effects of biology on ocean physics, coastal resources, and fisheries sustainability. The oceans are an important net sink for carbon dioxide released by the burning of fossil fuels. However, because the great spatial and temporal variability of fluxes of carbon dioxide into and out of the ocean are poorly understood, the nature and sustainability of this critical process is insufficiently understood. It is known that the uptake of carbon dioxide is related directly to the abundance of marine algae, which can only be effectively monitored on a global scale through ocean colour. The relative abundance of certain types of marine algae, also affect the ability of the oceans to absorb carbon dioxide by affecting the amount of calcium in the oceans, creating the potential for positive feedback between ocean warming and ocean biology. Changes in alga abundance and species composition affect the extent to which solar radiation is absorbed or reflected by the surface ocean. Such changes will alter local and global oceanic heat budgets, with implications for both local and global climate. Trace gases produced by marine algae and released from the ocean to the atmosphere can affect local climates directly through their effect on cloudiness. Half the world’s population lives within 100 kilometres of the ocean. This huge population has a large impact on the coastal zone. Rivers discharge large amounts of nutrients and sediments, much of it derived from human activities, into coastal waters, affecting water quality, recreational opportunities and coastal fisheries. Blooms of toxic algae affect human health both directly and indirectly, most notably through their effects on shellfish. Ocean colour will allow us to better detect, monitor, asses and mitigate the impacts of these events. Ocean colour measurements will provide data to support the rational management of living marine resources including aquiculture, Fish populations aggregate at areas of discontinuity between oceanic water masses; because phytoplankton growth may change across such boundaries, ocean colour gives the capability to map the surface manifestation of structure. Utilizing such information, scientists will be able to understand more fully how fish stocks respond to this structure. They will provide the tools that will give managers enhanced capability to intelligently manage and control these living marine resources. This will contribute to the efficient use and sustainability of these resources, The deliverables of ocean colour remote sensing reflect the major science issues identified in earlier sections. These issues are: (i) the role of the oceans in climate change; (ii) the assessment of natural and anthropogenic impacts in the coastal zone and shelf seas; (iii) the monitoring and management of fisheries and the ecosystem of which the fish are part. These deliverables can be categorized according to their utilization (unprioritized): (i) Science research products (time series, annual to decadel time scale) ; (ii) Operational products (short-term, daily to seasonal time scales); (iii) Methodological validation products. Within the first category are data for ocean models which will enhance our ability to forecast global change. These global scale observations will lead to the definition of biogeochemical premises and their characteristics which will serve as the basis for operational products. Operational products are required for environmental impact assessment, coastal zone management models, fisheries management and living resources protection. The third category data is required to validate certain research approaches, and methodologies used in assessing ocean colour. This category also includes inter-comparison of different ocean colour sensors to improve understanding of global scale processes and insure data set interoperability.

Supported by IOC for UNESCO.

Document available in English.

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