Data Quality Issues for ERA-40 Several projects have evaluated the performance of the ERA-40 data assimilation system and the post-processing of the data. These include :

• ECMWF has several web pages devoted to the performance of the ERA-40 model. These pages discuss some aspects of the quality of the analysis, validation of the hydrological cycle and ocean wave model products as well as the monitoring of the use of input observations by ERA-40.

• The DSS has performed an analysis of the EMOS interpolation package used by ECMWF for post processing of some of the data, especially the transformation of the spherical harmonic grids to the 2.5^o latitude-longitude grids. Inconsistencies on the order of .5 m/s were discovered in the U and V wind components. Please click here for more information.