European Reananlysis of the Global Climate System

Major components of the global climate system and their main interactions


Reanalysis production

The project focus is on production and assessment of multi-decadal reanalyses of the global climate system including atmosphere, land, ocean, and cryosphere, combined with consistent information on the carbon cycle.

Observational data sets

In addition, substantial work will be directed at data recovery, reprocessing, and quality control of input observations for reanalysis, with emphasis on improving and extending the usable satellite climate data records, and expanding access to early 20th century in-situ observations.

Key objectives

The ERA-CLIM2 project will produce reanalysis beyond the state-of-the-art to better serve climate applications. The following key requirements will be addressed:


  • Reanalysis data must provide an accurate representation of observed low-frequency variability and trends
  • Reanalyses must be extended further back in time to provide a sufficiently long record for climate studies and climate model validation
  • Reanalyses must include better representations of interactions and feedbacks in the coupled climate system (atmosphere-ocean-land-cryosphere)
  • Reanalyses must make use of as many input observations suitable for climate purposes as possible
  • Users must be provided with useful information about uncertainties relevant to the estimation of low-frequency variability and trends