page 8
CONTENTSREPORT ON THE 11TH CEOS PLENARY
News From the Working Group on Information Systems and Services
CEOS Working Group on Calibration and Validation
IGOS Strategic Implementation Team - Progress Report
The Global Ocean Data Assimilation Experiment
The Upper Air Measurements
Long-Term Continuity of Ozone Measurements
Ocean Biology ---This page
Global Observation of Forest Cover
Disaster Management Support
The Global Terrestrial Observing System
ISRO takes over CEOS Chair for 1998
Ocean Biology
Tasuku Tanaka, NASDA/EORC Trevor Platt, Bedford Institute of Oceanography (Canada)Project Definition
To implement a strategy for understanding ocean biogeochemical and ecosystem processes by combining long-term ocean-colour and other remotesensing satellite data with in situ measurements.
- Significance
The principal deliverable from ocean-colour missions is the concentration of chlorophyll pigments in the surface layer of the ocean. Chlorophyll concentration, an index of phytoplankton biomass, is the single most important property of the marine ecosystem whose magnitude we would like to know on synoptic scales. It has a dynamic range in the ocean of at least four orders of magnitude over regions and seasons. Phytoplankton use carbon dioxide as a substrate for their nutrition (photosynthesis). On a global scale, this activity (called the primary production) accounts for a carbon flux of about 50 Gtonnes per annum. Hence they play a significant role in the planetary carbon cycle. In addition, phytoplankton are important as the basis for the food web in the ocean that supports the integrity of the marine ecosystem and drives the continuity of renewable resources such as fish stocks. Because long time series of ocean-colour data can be established on synoptic scales, they afford the means to assess the extent to which the variance in the abundance of exploited stocks can be accounted for by fluctuations in ecosystem and environmental properties. Beyond their importance for fisheries management, ocean-colour data are significant as a tool for coastal zone management in general. Finally, chlorophyll concentration is easily the major determinant of the transmissibility of visible light through the ocean. This property is an important element in physical models that calculate the depth and temperature of the mixed layer, and therefore, ultimately, in numerical weather prediction. Thus, ocean-colour data are central to the issue of the interplay between physics and biology in the surface layer of the ocean. At larger scales, ocean-colour data provide the ideal vehicle for study of the effect of major events such as El Nino on the global marine ecosystem and on the fisheries embedded therein.
Feasibility
In March 1996, India launched the German sensor MOS, which provides local coverage. In August 1996, Japan launched the Japanese sensor OCTS (Figure 1) and the French sensor POLDER on the ADEOS mission, which operated until June 1997.
In August 1997, the USA launched the SeaWiFS sensor which is now producing global coverage (Figure 2).
Over and above these sensors already launched, a number of others are planned for the very near future. A certain plurality of sensors in orbit is essential if complete continuity (spatial and temporal) is to be achieved on a routine basis as we progress from the research to the operational mode of ocean-colour applications. Existing sensors for ocean colour are adequate with respect to spectral, spatial and temporal resolution to meet the basic needs of an IGOS Ocean-Biology Project. The availability of in situ data, so essential for the proper calibration and validation of the remotely-sensed product is assured through liaison with the core projects of the IGBP.
Organisation & Activities Because the objectives of the Ocean Biology
Project are entirely met by the activities of the International Ocean-Colour
Coordinating Group (IOCCG), responsibility for its implementation has been
entrusted by CEOS to the IOCCG. This group, whose foundation was endorsed
by a resolution of CEOS in 1995, came into being in March 1996. A Project
Office has been established at the Bedford Institute of Oceanography (Nova
Scotia, Canada). The IOCCG is an Affiliate Program of the Scientific Committee
on Oceanic Research (SCOR). The activities of the group are supported by
subscriptions from a number of space agencies: in this respect, the IOCCG
is entire-
(to be continued
on Page 9)
Next Page
Back to a Newsletters list