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

The figure below 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:

  • a data package containing satellite data, in situ data, and auxiliary information is distributed to the involved parties
  • participants apply their algorithms to these data 
  • a further set of data is distributed -- identical in format to the previous data package, but without any in situ observations – which is the selection subset
  • participants apply their final algorithms to the selection subset and submit the results to the CCI team
  • objective metrics are calculated for all submitted algorithms, which are then compared and an algorithm selected for implementation in the CCI project


  • The Algorithm Theoretical Baseline Document (ATBD) records the mathematical description of the algorithms to be used in the generation of data products.
  • The Climate Assessment Report (CAR) provides:
    • Feedback from the users on the delivered ECV data products with respect to the behaviour of the time series of ECV data on global and regional scales,
    • A comparison of the output of the CCI ECV project against outputs from other related projects
  • For the Comprehensive Error Characterisation Report (CECR), please see the UCR.
  • The purpose of the Data Access Requirements Document (DARD) is to identify, in detail, all the data required as input to the project. This includes satellite, in-situ and ancillary data, both ongoing and historical, and specifies the appropriate stage when the data is required. The document is updated as needed to reflect changes in data availability or project requirements.
  • The Product Specification Document (PSD) synthesises recommendations from the URD of the CCI ECV project into a detailed set of product specifications that respond to, and are continuously assessed against, the needs.  It is structured according to product types, product formats including metadata, resolution (temporal and spatial, grid format and projection), quality indicators (e.g. long term stability) and error budgeting.
  • The Product User Guide (PUG) describes to a user the instructions required on how to use the particular CCI ECV data products generated by each of the projects.  The contents of the PUGs will generally include subjects such as:
    • an overview of the project
    • a guide to getting started with the data
    • a description of the features of each of the products
    • detailed description of the data files
    • descriptions of the tools that can be used with the data
    • worked examples on how to use the data
    • a dictionary of acronyms, abbreviations and jargon that may be encountered;
    • list of references
  • The Product Validation and Inter-comparison Report (PVIR) provides a description of the assessments used to validate the products generated by each of the CCI ECV teams.
  • The System Specification Document (SSD) describes the configuration and implementation of the system used to process the CCI ECV data products.
  • The System Verification Report (SVR) gives a description of all activities executed to validate to the correctness of the production system against the prototype system. The tests described in the report are made to verify, as far as possible, that future datasets produces by the production system will be identical to the products generated by the prototype system.
  • The Uncertainty Characterisation Report (UCR) documents the best current understanding of uncertainties (i.e., components of error distributions) in the each CCI ECV team’s observations and products.  
  • The User Requirement Document (URD) specifies the requirements for the ECV products from the user’s point of view in terms of product characterisation. The document:
    • Provides an overview of the functionality of the products that the end-user expects to obtain from each of the CCI projects
    • Provides a repository for all the requirements that will allow the end-user to exploit the products to be offered by each CCI project