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Ocean color
is an "essential climate variable" needed to support the carbon cycle
monitoring requirements of the UNFCCC
(United Nations Framework Convention on Climate Change). It is also
a climate variable that cannot be globally monitored without using satellite
observations. The GlobColour project has been initiated and funded by the ESA Data User Element Programme to develop a satellite based ocean color data service to support global carbon-cycle research and operational oceanography. The Agency sees this project as a necessary element brick of the future EU GMES Marine Core Service, with a service and system being developed and demonstrated with the aim of being operational at the end of the project. In parallel, the Agency is planning the continuity of MERIS in 2012 on board Sentinel-3. GlobColour aims to satisfy the scientific requirement for a long time-series (1997-2007) of consistently calibrated global ocean color information with the best possible spatial coverage. This requirement has been specified by the global ocean color user community, as represented in the project by the International Ocean Colour Coordinating Group (IOCCG) and the International Ocean Carbon Coordination Project (IOCCP). The operational oceanography requirements are expressed by the UK MetOffice. A critical component of GlobColour is ocean color data merging, as it provides a method for the rationalisation of space missions and data distribution. Alternative data-merging methods that start from both radiance and derived bulk properties (such as surface chlorophyll concentration) have been tested and the final merging algorithm choice has been made following an algorithm inter-comparison and trade-off analysis against in situ data. The GlobColour
service distributes global data sets of chlorophyll concentration, water
leaving radiances, diffuse attenuation coefficient, coloured dissolved
and detrital organic materials, total suspended matter or particulate
backscattering coefficient, turbidity index, cloud fraction, quality indicators.
Distribution of other products is upcoming (e.g., transparency, heated
marine layer), or considered. A real-time
service is being developed for operational oceanography purposes and will
deliver on a daily basis a global ocean color data set derived from MERIS
and MODIS used as an input to
forecast models of the state of the ocean.
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