Access to global radiosonde and surface station observations including ERA-40 Assimilation Model Metadata from NCAR

The ECMWF 45-year Re-Analysis (ERA-40) project has produced a set of quality control (QC) metadata specific to each individual observation used for the period covering September 1957 to August 2002. This comprehensive set of global observations, from multiple data sources, was assimilated into an ECMWF model and produced the ERA-40. The metadata gathered during the assimilation process were appended to the input observations and when completed are called feedback records. The combination of observed data and the assimilation model metadata provide potential benefits for observational studies by making supplemental QC indicators available, and augment research based on ERA-40 with observation versus model comparative metrics.

The Data Support Section (DSS) of the Scientific Computing Division at the National Center for Atmospheric Research (NCAR) has reformatted the radiosonde and surface station feedback records into an easy to use ASCII format. The feedback metadata available includes QC flags for entire reports and individual data values, and differences between observed values and interpolated six-hour forecasts and final model analyses. Further, in the case of QC report or data rejection some details why rejection occurred are given in the codes provided.

Web interfaces give direct access to online files that are organized in weekly blocks. Through the same interfaces users have access to complete dataset documentation and software to read the data. The software is easy to use and supported by the DSS data specialist. Future versions of the web interfaces will include options for spatial and temporal sub-setting, and producing output in selectable formats. These data are available only for non-commercial research in the U.S. and some locations in Canada. When practical, the data are transferred using the web or File Transfer Protocol (FTP). Upon request, the DSS can also provide data on various writeable media. The radiosonde feedback dataset can be found at http://dss.ucar.edu/datasets/ds366.0 and similarly, the land surface station feedback dataset is at http://dss.ucar.edu/datasets/ds476.0.