AUTOMATED VALIDATION FOR SUMMARY OF THE DAY TEMPERATURE DATA

A new quality assurance system was developed and implemented operationally for the National Climatic Data Center's Cooperative Summary of the Day (SOD) quality assurance process. The system uses rules-based GIS technology to fully automate spatial quality assurance of observed daily temperature values. Gridded fields are derived from quality controlled ASOS (Automated Surface Observation System) and AWOS (Automated Weather Observing System) hourly and daily temperature values as "ground truth" to quality assure the Cooperative Observers Network (COOP) daily temperature data. This automated temperature validation (TempVal) system replaces the interactive Graphical Edit Analysis (GEA) temperature validation system. Parallel tests of the old and new systems were made using regression analysis. Manual comparisons between the systems using outliers exceeding a pre-described threshold were performed. The results of the tests will be shown. Higher confidence in TempVal is attributed to a change in methodology (using grid fields) and access to higher quality data for use as "ground truth". The GEA methodology derives and uses three climatological best neighbors to quality assure a flagged data value. Additionally, TempVal is able to estimate daily replacement temperatures for any number of missing days whereas the GEA system can only generate temperature values under certain conditions.