Ana4MIPs is a project designation in the Earth System Grid Federation (ESGF) and is closely aligned to obs4MIPs, supporting the CMIP model intercomparison and validation exercise. Ana4MIPs contains a selection of data from the major reanalysis efforts underway today. Each dataset is reformatted similarly to facilitate comparison with each other and with the CMIP models.
One of the key differences between ana4MIPs and obs4MIPs is that reanalyses have uncertainty related to the underlying model forecasts, however, the dynamical state fields, such as temperature heights, wind and surface pressure, are typically close to the observation fields. Uncertainty in reanalysis is better addressed in the CREATE-IP project where many more monthly and high frequency data is available.