OceanColour-CCI

OC-CCI FAQs

This page provides frequently asked questions about OC-CCI data. If you have a question you can't find the answer to here, please contact our helpdesk.

Where and how can I obtain OC-CCI data?

The OC-CCI data is available via multiple providers and different access mechanisms. The table below provides a summary.

Why are OC-CCI data available from multiple locations?

The OC-CCI R&D and production is supported through different funding sources each of which make data available. Furthermore, for user benefit, the project provides data using different methods (i.e., OPeNDAP, OGC, etc) that are only available at some sites. Finally, some users may be more familiar with using some data locations (e.g., CEDA). The table above provides some guidance to help you select the most appropriate location to access data from.

What is the spatial and temporal coverage?

OC-CCI provides global ocean-colour products at 4 km and 1 km spatial resolution. The time series spans from 4th September 1997 to the present, with daily, 5-day, 8-day, monthly and annual composites available at 4 km, while the 1 km products are available as daily, 8-day, monthly and annual composites. Data are updated for the current version following a quarterly schedule with the most recent products available directly from PML.

Which OC-CCI variables are available?

OC-CCI distributes Level-3, non–gap-filled (binned and mapped) products at 4 km and 1 km spatial resolution. The 4 km OC-CCI dataset includes chlorophyll-a concentration, as well as the following products at six bands (i.e., 412, 443, 490, 510, 560 and 665 nm): remote-sensing reflectance (Rrs), inherent optical properties (atot, aph, adg, bbp), diffuse attenuation coefficients at 490 nm bands (Kd490), number of observations from each satellite mission and associated per-pixel uncertainties. The 1 km OC-CCI products include only chlorophyll-a concentration and Rrs at the same six spectral bands. For more detailed information, please refer to the OC-CCI documentation.

Where can I find the documentation?

See https://climate.esa.int/en/projects/ocean-colour/, under 'Key Documents'. For the majority of users, the 'Product User Guide' contains the essential information needed to understand and work with the OC-CCI products.

Do you provide gap-filled data?

OC-CCI is a climate-quality data set that is only available at Level 3 (non -gap filled). Evaluations have shown that gap filled L4 data have poorer error characteristics than L3 and gaps may be seasonally biased and so gap-filling may give erroneous time series or trends.

Do you provide uncertainty information?

Yes, OC-CCI has per-pixel uncertainties in terms of root-mean square uncertainty and bias with respect to in situ data via matchups of in situ samples with the 4 km pixels. Hence, the uncertainties include impacts of un-measured natural variability within pixels.

Are higher resolution data available?

Yes, PML generates a 1 km version, with just Rrs and chlorophyll variables, primarily for internal use but made available externally via the PML web portal and THREDDS servers.

Is OC-CCI suitable for coastal areas?

Coastal areas represent a wide range of environments usually with more complex optical characteristics than open-ocean waters For example, coastal waters may contain suspended particulates, possibly of riverine origin, so chlorophyll-a is not necessarily the dominant driver of their optical properties. Nevertheless, the in situ data used to evaluate OC-CCI products include coastal waters, while the Optical Water Type methodology may classify coastal waters as optically distinct to offshore waters and per-pixel uncertainties are specific to optical water types. The uncertainties are generally higher for coastal waters.

How do I acknowledge OC CCI data?

To acknowledge OC CCI please include:
"The European Space Agency (ESA) Climate Change Initiative (CCI) Ocean Colour data are developed and produced through funding and resources from ESA, Copernicus Climate Change Service (C3S) and the NERC EO Data Analysis and AI Service (NEODAAS)."

How do I reference OC CCI data?

The correct reference for OC-CCI products is:
Sathyendranath, S, Brewin, RJW, Brockmann, C, Brotas, V, Calton, B, Chuprin, A, Cipollini, P, Couto, AB, Dingle, J, Doerffer, R, Donlon, C, Dowell, M, Farman, A, Grant, M, Groom, S, Horseman, A, Jackson, T, Krasemann, H, Lavender, S, Martinez-Vicente, V, Mazeran, C, Mélin, F, Moore, TS, Müller, D, Regner, P, Roy, S, Steele, CJ, Steinmetz, F, Swinton, J, Taberner, M, Thompson, A, Valente, A, Zühlke, M, Brando, VE, Feng, H, Feldman, G, Franz, BA, Frouin, R, Gould, Jr., RW, Hooker, SB, Kahru, M, Kratzer, S, Mitchell, BG, Muller-Karger, F, Sosik, HM, Voss, KJ, Werdell, J, and Platt, T (2019) An ocean-colour time series for use in climate studies: the experience of the Ocean-Colour Climate Change Initiative (OC-CCI). Sensors: 19, 4285. doi:10.3390/s19194285

In addition, each version of OC-CCI products has its own DOI. Please provide reference to the appropriate DOI.
For Version 6.0 this is:
Sathyendranath, S.; Jackson, T.; Brockmann, C.; Brotas, V.; Calton, B.; Chuprin, A.; Clements, O.; Cipollini, P.; Danne, O.; Dingle, J.; Donlon, C.; Grant, M.; Groom, S.; Krasemann, H.; Lavender, S.; Mazeran, C.; Mélin, F.; Müller, D.; Steinmetz, F.; Valente, A.; Zühlke, M.; Feldman, G.; Franz, B.; Frouin, R.; Werdell, J.; Platt, T. (2023): ESA Ocean Colour Climate Change Initiative (Ocean_Colour_cci): Monthly climatology of global ocean colour data products at 4km resolution, Version 6.0. NERC EDS Centre for Environmental Data Analysis, date of citation. https://catalogue.ceda.ac.uk/uuid/690fdf8f229c4d04a2aa68de67beb733/.

For other versions, please see https://climate.esa.int/en/projects/ocean-colour/data/#citing-ocean-colour-cci-information-and-data-products.