An operational mixing height data set from routine radiosoundings at Lindenberg: Methodology

Abstract

High-resolution vertical profiles of temperature, humidity and wind from the operational radiosoundings performed routinely four times per day at the Meteorological Observatory Lindenberg - Richard-AßmannObservatory are analysed to provide routine estimates of the mixing height (MH). Different criteria are employed to deduce the MH, and the height where the Richardson number (Ri) exceeds a critical value is taken as a standard. This criterion is applicable for all types of boundary layer stratification. Differences between the Ri-based MH estimate and other characteristic heights are used to derive both an uncertainty estimate and a quality flag for each single MH value. A more than 10 years MH data set has been created. Reliable MH values (with an uncertainty of not more then 10 % or 50 m, respectively) could be obtained for about 40-60 % of the profiles depending on the radiosonde launch time (with the highest success rate for the 12 UTC and the most uncertain estimates for the 18 UTC soundings). Statistical analysis of the MH data set showed that the monthly mean MH values at 00 UTC range between 150 m and 200 m in summer and between 250 m and 350 m in winter. Mean 12 UTC MH values are around 500 m in winter and between 1200 m and 1400 m in early summer.