Robust Automated Quality Assurance of Radiosonde Temperatures

Abstract

This paper presents a description of the fully automated quality-assurance (QA) procedures that are being applied to temperatures in the Integrated Global Radiosonde Archive (IGRA). Because these data are routinely used for monitoring variations in tropospheric temperature, it is of critical importance that the system be able to detect as many errors as possible without falsely identifying true meteorological events as erroneous. Three steps were taken to achieve such robust performance. First, 14 tests for excessive persistence, climatological outliers, and vertical and temporal inconsistencies were developed and arranged into a deliberate sequence so as to render the system capable of detecting a variety of data errors. Second, manual review of random samples of flagged values was used to set the ?thresholds? for each individual check so as to minimize the number of valid values that are mistakenly identified as errors. The performance of the system as a whole was also assessed through manual inspection of random samples of the quality-assured data. As a result of these efforts, the IGRA temperature QA procedures effectively remove the grossest errors while maintaining a false-positive rate of approximately 10%.