GLOBAL CLIMATE OBSERVING SYSTEM
ESSENTIAL CLIMATE VARIABLE - Ocean colour |
| Domain | Oceanic | Description | Ocean colour is measured as the ocean colour radiance (OCR). OCR is the wavelength-dependent solar energy captured by an optical sensor looking down at the sea surface. These water-leaving radiances contain information on the ocean albedo and information on the constituents of the sea water, in particular phytoplankton pigments such as chlorophyll-a. Data analysis is not easy as satellite measurements also include radiation scattered by the atmosphere and ocean surface. The relatively weak OCR signal is some 5-15% of the strength of the incident solar radiation. OCR products are used to assess ocean ecosystem health and productivity, and the role of the oceans in the global carbon cycle, to manage living marine resources, and to quantify the impacts of climate variability and change. OCR products, in particular chlorophyll-a, are also required by the modelling community for the validation of climate models, and for use in data assimilation systems for reanalysis and initialising forecasts. [GCOS-195 5.3.7] |
| Sub-domain | Surface |
| Full Name | Ocean colour |
| Satellite Signficant Contribution | Yes  |
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| GCOS Actions |
Action
Status* | Description | Who | Time Frame | Performance Indicator | Cost Implications |
O15
Cat-C | Implement continuity of ocean colour radiance datasets through the plan for an Ocean Colour Radiometry Virtual Constellation. | CEOS space agencies, in consultation with IOCCG and GEO. | Implement plan as accepted by CEOS agencies in 2009 | Implement plan as accepted by CEOS agencies in 2009 | 30-100M US$ (10% in non-Annex-I Parties). |
O23
Cat-D | Establish a global network of long-term observation sites covering all major ocean habitats and encourage collocation of physical, biological and ecological measurements. | Parties’ national research and operational agencies, supported by GOOS/PICO, OOPC, GRAs, and other partners. | 2014 | Reporting on implementation status of network. | 30-100M US$ (50% in non-Annex-I Parties). |
*GCOS-195 Status Categories:
Category A: Action completed, perhaps exceeding reasonable expectations. Very good progress on ongoing tasks.
Category B: Action largely completed according to expectation. Good progress on ongoing tasks.
Category C: Moderate progress overall, although progress may be good for some part of the action.
Category D: Limited progress overall, although progress may be moderate or good for some part of the action.
Category E: Very little or no progress, or deterioration rather than progress.
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| GCOS Products | |
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| CEOS Response | [O15 (O.6.1)]
2015 Update: The CEOS OCR-VC continues to actively coordinate Space Agency plans for instrumentation from both polar and geostationary satellites. The OCR-VC works in collaboration with the International Ocean Colour Coordinating Group (IOCCG) and has recently updated plans for ocean color sensors from geostationary orbit (IOCCG Report 12), sensor requirements (IOCCG Report 13), and in flight calibration (IOCCG Report 14) all available from the IOCCG.org web site.
With respect to ECV generation, International efforts to produce time series of ECVs include:- NASA-GSFC: Lw and Chl time series from SeaWiFS, Aqua, Terra, MERIS
- MEaSUREs (NASA): inherent optical properties (IOPs) from SeaWiFS, Aqua, MERIS
- GLOBColour (ESA): time series of merged data from SeaWiFS, Aqua, MERIS
- ESA’s CCI program: new (Dec 2013) merged and bias corrected times series from MERIS, MODIS, SeaWiFS with associated per-pixel uncertainty information. The following ECV products are being delivered from a multi-mission combination of SeaWiFS, MODIS/Aqua, MERIS, and eventually VIIRS and Sentinel-3 OLCI observations. The following products are being delivered, covering the time period 1997- 2015:
- Water-leaving radiances (412, 443, 490, 510, 555 and 670 nm)
- Chlorophyll-a concentration, diffuse attenuation coefficient (490 nm) and inherent optical properties (412, 443, 490, 510, 555 and 670 nm).
Additional tests are performed on earlier CZCS data from 1978-1986. The products cover Case 1 waters (oceanic) and plans are underway to develop prototype ECV products for Case 2 (coastal) waters. Work is being conducted in consultation with the International Ocean Colour Coordinating Group and the OCR Virtual Constellation. Close collaboration with the NASA Ocean Biology Processing Group and NASA MEaSURES project has been maintained throughout.
See: www.esa-oceancolour-cci.org
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