What quality control and homogeneity procedures are applied?
Series of the best possible quality are provided for ECA&D by the participating institutions. In addition, common quality control procedures are applied to all series using various algorithms (see Publications > ATBD). These quality control procedures lead to flags (“OK”, “suspect” or “missing”) assigned to individual data. Although data validation has been careful, it can never be excluded that some errors remain undetected. The risk for such errors is greatest in the recent data that stem from synoptical messages, because these data did not undergo the validation process in the participating institutions. Apart from errors at individual days, changes in observation practices may have introduced inhomogeneities of non-climatic origin in long time series. These inhomogeneities may severely affect the assessment of changes in extremes. For evaluation of the homogeneity of the time series in ECA&D a two step testing procedure was followed (see Publications > ATBD). First, four common hom
