Frequently Asked Questions (FAQs)

If you would like to raise a question, please contact the CCI ODP helpdesk

Q: What is an ECV?

A: Over the last decade, the Global Climate Observing System (GCOS), in support of the UNFCCC, have put together a set of requirements for satellite data to meet the needs of the climate change community. These are broken down into key parameters of the Earth system, or 'Essential Climate Variables' (ECVs) as they are known. The specifications given by GCOS for each ECV data product are designed to provide information to characterise the state of the global climate system and enable long-term climate monitoring. 

GCOS defines 54 ECVs, with are required to support the work of the UNFCCC and the IPCC. These are described in the table below. All ECVs are technically and economically feasible for systematic observation. It is these variables for which international exchange is required for both current and historical observations.

Q: What is the CCI programme?

A: The European Space Agency (ESA) Climate Change Initiative (CCI), is a programme whose aim is to provide stable, long-term, satellite-based ECV data products for climate modellers and researchers. This can be achieved by realising the full potential of the long-term Earth Observation (EO) archives that ESA, together with its member states, has established over the last 30 years, as a significant and timely contributions to the ECV databases required by United Nations Framework Convention on Climate Change (UNFCCC). 

The ECVs will be derived from multiple satellite data sets (not just ESA but all sources via international collaboration) and include specific information on the errors and uncertainties of the data set. Comprehensive information will also be provided on calibration and validation, long term algorithm maintenance, data curation and reprocessing. The Climate Change Initiative will bring together European expertise covering the full range of scientific, technical and development specialisations available within the European Earth Observation community, and will establish lasting and transparent access for global climate scientific and operational communities to its results.  

The €75m CCI programme, will run from 2009 to 2016 and consists of three stages: requirement analysis, algorithm development and prototype ECV building; ECV production and system development; and user analysis and feedback. Within the programme ECV have been generated for all three domains, atmospheric, oceanic and terrestrial.  

An extension to the CCI programme, called CCI+, is planned.

Q: How do I get the CCI data?

A: In the CCI Open Data Portal we have data products from the Climate Change Initiative Essential Climate Variables (ECVs), as well as links to further information and documentation.

For each ECV we hold different processing levels and products, so please have a look at the catalogue or dashboard to search the data holdings. A CCI Toolbox also makes the same data available.

Q: Who do I contact if I have problems downloading the data or want to know more information?

A: The data can be downloaded by FTP, HTTP, (other protocols) and are fully open, no registration required. If you have problems downloading the data, please contact the CCI Open Data Portal Helpdesk.

Q: How do I find out more about an individual CCI project?

A: Details for each individual CCI project can be found in the project section of this site - via the search or the 'project link in the drop down menu'. Pages on each project describe in detail the goals, provides access to key documents, presentations as well as access to the generated ECV datasets.

Q: What are the development phases for each CCI project and their associated documentation?

A: The figure on the right identifies the 5 distinct tasks within the CCI ECV projects and the deliverables associated with each.



The evolution of the ECV datasets, as envisaged initially in Phase 1, was linear, going from user consultation, algorithm selection, and prototype development to product generation and validation, after which it was considered that the system and products would be ready for being made operational. However, for Phase 2, a cyclic approach has been adopted, which has led to an agile and versatile system, able to respond to new developments in the field, and capable of updating the products in response, such that the users will continue to receive the best products possible.


Each of the CCI ECV projects carry out one or more Round Robin exercise as part of their algorithm selection exercise. The exercise involves both the project team and external participants, with the aim of undertaking an objective comparison of the available algorithms and selecting the most appropriate. The Round Robin exercise proceeds as follows:


Q: How do I find more about how the data records were put together?

A: There is a Product User Guide (PUG) for each variable, and more details can be found on the project websites. Links to further information are also provided via the ECV Dashboard. You can also email the helpdesk who will forward your question to the appropriate experts/data producers. 

Q: How do I cite the data?

A: If you use the data in a presentation or publication, please acknowledge the ESA Climate Change Initiative, and the data producer. Detailed instructions on how to do this can be found in the terms and conditions files alongside the data, but an example is given below:

AuthorName1, AuthorName2 (<year>): ESA <ECV-name> Climate Change Initiative (ESA <ECV short name> CCI) data: <Product name and Version number> via Centre for Environmental Data Analysis, Date of citation

Q: How do I acknowledge ESA Climate Change Initiative funding in scientific outputs such as papers and posters?

A: When acknowledging European Space Agency Climate Change Initiative funding in scientific outputs, such as peer-reviewed papers or conference posters etc. please use the following text:

This research has been funded by the European Space Agency (ESA) as part of the [add project name e.g. Biomass_cci] project of the Climate Change Initiative (CCI) (ESA ESRIN/Contract No. [add contract number here])