"ERA-CLIM will develop observational datasets suitable for global climate studies, with a focus on the past 100 years. These datasets will include atmospheric, oceanic, and terrestrial observations from a variety of sources, high-resolution global reanalysis products of the observations, and associated data quality information needed for climate applications. The project will use existing climate data records and make a substantial contribution to filling known gaps in these records. Proposed data recovery efforts will focus on upper-air observations made in the first half of the 20th century, as well as near-surface observations of wind and humidity, in all regions of the globe.A specific goal for the project is to improve the quality and consistency of climate observations through reanalysis. Together with other in-situ and remote-sensing datasets available from existing data archives, the observations collected for ERA-CLIM will be included in a newly developed Observation Feedback Archive. Quality feedback information for this archive, including data departures and bias estimates, will be generated during several new pilot reanalyses, as well as from existing reanalysis datasets. The pilot reanalyses and the Observation Feedback Archive will be made available to users world-wide as a unique resource for climate research and observational studies of the Earth system."