ERA-CLIM stands for European Reanalysis of Global Climate Observations. ERA-CLIM is a collaborative research project involving 9 partners, funded by the European Union for a three-year period beginning January 2011. The goal is to prepare input data and assimilation systems for a new global atmospheric reanalysis of the 20th century. This involves recovery and digitisation of early meteorological observations, reprocessing and recalibration of radiance measurements from satellites, and preparation of climate-quality atmospheric forcing data and boundary conditions. These input data sets will be used in several pilot reanalyses, including an exploratory climate reanalysis of the 20th century based on surface observations only; a corresponding high-resolution reanalysis of land-surface parameters, and a new atmospheric reanalysis of the satellite era from 1979 to present. Access to the ERA-CLIM pilot reanalyses, and to all observations used to produce them, will be provided via the internet.

Key objectives for ERA-CLIM are to:

• Improve the available observational record for the early 20th century
• Prepare data sets and assimilation tools needed for global reanalysis
• Provide information about data quality by means of pilot reanalyses
• Develop an Observation Feedback Archive facility for users
• Assess and reduce uncertainties in reanalysis data

ERA-CLIM is part of a larger effort to:

• Improve climate data access, data quality, and transparency
• Develop a sustainable capability for data recovery and reanalysis
• Develop core resources for future GMES climate services