European Reananlysis of the Global Climate System
Work packages


ERA-CLIM project activities are organised in four scientific work packages:

  • Recovery, imaging, and digitisation of historical observations and metadata (WP1)
  • Preparation of satellite observations, boundary conditions, and forcing data (WP2)
  • Integration of observational climate data sets (reanalyses) (WP3)
  • Quantifying and reducing data uncertainties (WP4)

with one additional work package for project management and coordination (WP5).


The chart to the right shows the allocation of project resources by work package, coloured according to institutional participation.


WP1: Recovery, imaging, and digitisation of historical observations and metadata.

This is the largest work package, involving 6 project partners and requiring more than 50% of human resources available to the project. Tasks and activities in this work package are coordinated by UBERN, who will develop and host a metadatabase and data exchange facilities to allow the distribution of imaged data sheets and digitised data files. An inventory of upper-air data known to be available in various data archives, in the form of images or hard-copy, has been compiled for this purpose, and a similar inventory will be developed for historical remote sensing data. A web interface will be created to allow on-screen digitisation by all partners. Millions of previously inaccessible historical meteorological data (from kites, weather balloons, surface stations, and ships) will be recovered, digitised, checked for quality, and made available for reanalysis (in WP3) and other applications.


WP2: Preparation of satellite observations, boundary conditions, and forcing data.

Activities in this work package are coordinated by UKMET. A key task is the development of a self-consistent SST and sea-ice forcing dataset extending back to the year 1900. Other important tasks include the provision of reprocessed satellite observations for reanalysis, including recalibrated level-1b radiance data, reprocessed Atmospheric Motion Vector data from geostationary and polar orbiter imagery, and reprocessed trace gas information from polar-orbiting satellite instruments. Opportunities for extending the usable satellite data record back in time will be investigated. The work will also include the selection and acquisition of land-surface and atmospheric forcing data products required for a 20th century atmospheric model integration, consistent with CMIP5 specifications.

WP3: Integration of observational climate data sets.

Tasks in this work package, coordinated by ECMWF, involve the development of the necessary tools and facilities for integrating the data prepared in WP1 and WP2, and for assessing and improving the quality of these data. This includes the production of an ambitious series of pilot reanalyses, including, for example, an extended low-resolution (125km) atmospheric reanalysis spanning the 20th century, with high-resolution (25km) global land-surface products. An important additional product of this work package is the Observation Feedback Archive, which will give users access to all observations used (or usable) for reanalysis, together with important quality information about those data.

WP4: Quantifying and reducing uncertainties.

Tasks in this work package are coordinated by UNIVIE. The overall objective is to quantify and, if possible, remove biases in both observations and assimilated data. Time changing biases are a major obstacle for climate change assessment and must be specifically addressed. Assessment of biases is challenging since they can usually not be derived from sample statistics but only through comparison with independent data that are in the best case traceable to some transfer standard. WP4 seeks to quantify both systematic and random errors, and, where possible, to correct the systematic errors. WP4 will make use of the pilot reanalyses and Observation Feedback Archive produced in WP3, since these facilitate intercomparison between datasets and also allow estimating the impact of different observing systems on the assimilated products. Results from WP4 will be communicated to WP1 to assist data providers in their quality control; to WP2 to detect possible systematic errors in the forcing data; and to WP3 to help correct systematic errors in the assimilating model, and also to provide guidance for sensitivity experiments that reveal the dependency of analysis quality on data assimilation issues.


WP5: Project management and coordination.

This work package is led by ECMWF and representing 2.5% of the total project effort. It includes all coordination and management activities required for successful completion of the project.