Global climate datasets based on Earth observations are used for a wide range of applications including monitoring of the climate system, input for simulations of climate variability and change, studies of impacts, adaptation and vulnerabilities of on natural and managed ecosystems to climate change, development and management of human activities (e.g. transportation, energy, tourism, health), and management of risks associated with climate and high impact weather extremes. These datasets are also being used increasingly to develop, initialise and evaluate numerical models for climate prediction and projection on a range of time and space scales, and in global reanalyses. Thus, the community using global climate datasets is far larger than the scientists who prepare and analyse them for their own studies. Users need authoritative information on quality, maturity and error characteristics, and appropriate documentation of the underlying assumptions and methodologies used to produce these datasets, to ensure their proper interpretation and use in the intended applications.

To address this need, the World Climate Research Programme (WCRP) and the Global Climate Observing System (GCOS) urge agencies and organizations that sponsor the development of these datasets to support and fund the international expert groups who develop these datasets to ensure their adequate characterization and documentation.. Under the auspices of the GCOS-WCRP Observations and Assimilation Panel, the European Space Agency hosted a workshop in Frascati, Italy on 18-20 April 2011 to prepare a technical report on the evaluation and documentation of global climate datasets that are based on satellite observations. About fifty experts from thirteen countries considered the current methodology in producing, evaluating and documenting eight of the GCOS Essential Climate Variables (ECVs) covering the atmospheric, oceanic and terrestrial domains.

In considering the specific ECVs, the workshop participants discussed a number of ideas for improving the evaluation and provision of information on global climate datasets, and identified some best practices and a number of common issues. We will share the workshop findings and recommendations with the session participants. For example, two key issues addressed were the need to identify indices of maturity and uncertainty in order to convey information on the strengths and weaknesses of datasets, and the need to promote and support the conduct of independent assessments of datasets as part of the continuing process of evaluation. The first issue on maturity and uncertainty indices is aimed at enhancing the dialogue between users and producers of datasets, and the second issue recognises that, while self-assessments are invariably carried out by dataset producers, assessments by independent experts markedly enhance the utility and encourage improvements in datasets. An outcome of the workshop is the commencement of an inventory on the status of ECV datasets with the objective of supporting the activities of both dataset producers and users. A full report of the workshop is under preparation and a summary is being prepared for publication in the Bulletin of American Meteorological Society.