Access to global radiosonde and surface station observations including ERA-40 assimilation model metadata from NCAR

The ERA-40 project has produced a valuable archive of observational data feedback record products covering a 45-year period, September 1957-August 2002. The archive includes global radiosonde and surface station data derived from multiple source datasets. Assimilation model metadata accompany the observational data, providing potential benefits for observational studies by making supplemental QC indicators available. Observational values versus model determined fields yield comparative metrics that provide additional information for studies based on ERA-40 model products. Access to the feedback record archives is offered in several ways: • Native ASCII files are online and available for direct download by web and FTP transfer. Temporal and spatial subset extraction is also possible by delayed mode processing. • Data may be provided on writeable media, upon request. • All feedback record data are available to NCAR users from the MSS. The primary focus is to provide a high quality archive with an emphasis on data delivery. The NCAR ERA-40 feedback record archive has been designed to promote efficient access for a large variety of users and requests. It is actively supported by data specialists who provide consultation on the archive products, locally developed software, and individual requests that require non-routine data processing and possible data delivery on media. Many data services and access methods for the archive are now available while still more will be developed in the future.