GLOBAL HISTORICAL CLIMATOLOGY NETWORK (GHCN) QUALITY-CONTROL OF MONTHLY TEMPERATURE DATA

All geophysical data bases need some form of quality assurance. Otherw ise, erroneous data points may produce faulty analyses. However, simpl istic quality control procedures have been known to contribute to erro neous conclusions by removing valid data points that were more extreme than the data set compilers expected. In producing version 2 of the g lobal historical climatology network's (GHCN's) temperature data sets, a variety of quality control tests were evaluated and a specialized s uite of procedures was developed. Quality control traditionally relies primarily on checks for outliers from both a time series and spatial perspective, the latter accomplished by comparisons with neighbouring stations. This traditional approach was used, and it was determined th at there are many data problems that require additional tests to detec t. In this paper a suite of quality control tests are justified and do cumented and applied to this global temperature data base, emphasizing the logic and limitations of each test. (C) 1998 Royal Meteorological Society.