An Ocean-Colour Time Series for Use in Climate Studies: The Experience of the Ocean-Colour Climate Change Initiative (OC-CCI)
Abstract
Ocean colour is recognised as an Essential Climate Variable (ECV) by the Global Climate Observing System (GCOS); and spectrally-resolved water-leaving radiances (or remote-sensing reflectances) in the visible domain, and chlorophyll-a concentration are identified as required ECV products. Time series of the products at the global scale and at high spatial resolution, derived from ocean-colour data, are key to studying the dynamics of phytoplankton at seasonal and inter-annual scales; their role in marine biogeochemistry; the global carbon cycle; the modulation of how phytoplankton distribute solar-induced heat in the upper layers of the ocean; and the response of the marine ecosystem to climate variability and change. However, generating a long time series of these products from ocean-colour data is not a trivial task: algorithms that are best suited for climate studies have to be selected from a number that are available for atmospheric correction of the satellite signal and for retrieval of chlorophyll-a concentration; since satellites have a finite life span, data from multiple sensors have to be merged to create a single time series, and any uncorrected inter-sensor biases could introduce artefacts in the series, e.g., different sensors monitor radiances at different wavebands such that producing a consistent time series of reflectances is not straightforward. Another requirement is that the products have to be validated against in situ observations. Furthermore, the uncertainties in the products have to be quantified, ideally on a pixel-by-pixel basis, to facilitate applications and interpretations that are consistent with the quality of the data
Document Details
- Document Type
- Technical Report
- Publication Date
- Oct 03, 2019
- Accession Number
- AD1099540
Entities
People
- Alex Farman
- Andre B. Couto
- Andrei Chuprin
- Andrew Horseman
- Ben Calton
- Bryan A. Franz
- Constant Mazeran
- Craig Donlon
- Frederic Melin
- Gene Feldman
- James Dingle
- Jeremy Werdell
- Mark Dowell
- Mike Grant
- Paolo Cipollini
- Richard Jr W. Gould
- Roland Doerffer
- Stanford B. Hooker
- Steve Groom
- Victor Martinez-vicente
Organizations
- United States Naval Research Laboratory