Determining the temporal variability in atmospheric temperature profiles measured using radiosondes and assessment of correction factors for different launch schedules

Abstract. Radiosondes provide one of the primary sources of upper atmosphere temperature data for numerical weather prediction, the assessment of long-term trends in atmospheric temperature, the study atmospheric processes and provide a source of intercomparison data for other temperature sensors e.g. satellites. When intercomparing different temperature profiles it is important to include the effect of temporal mis-match between the measurements. To help quantify this uncertainty the atmospheric temperature variation through the day needs to be assessed, so that a correction and uncertainty for time difference can be calculated. Temperature data from an intensive radiosonde campaign were analysed to calculate the hourly rate of change in temperature at different altitudes and provide recommendations and correction factors for different launch schedules. Using these results, three additional longer term data sets were analysed to assess the diurnal variability temperature as a function of altitude, time of day and season of the year. This provides data on the appropriate correction factors to use for a given temporal separation and the uncertainty associated with them. A general observation was that 10 or more repeat measurements would be required to get a standard uncertainty of less than 0.1 K h−1 of temporal mis-match.