Upper air soundings during POLARSTERN cruise PS109 (ARK-XXXI/4)

Upper air soundings onboard Polarstern are normally performed once a day to measure vertical profiles of air pressure, temperature, relative humidity and the wind vector. Helium filled balloons (TOTEX 600 g) were used to carry Vaisala RS92-SGP radiosondes. Whenever possible, the launches were carried out shortly before 11 UTC, in order to reach 100 hPa at 12 UTC. Condensed measurements (TEMP Format FM-35, BUFR) were transferred without delay into the Global Telecommunication System GTS, were they contribute to the world wide weather forecast analysis. The profile data were taken every 5 seconds, which results in a vertical resolution of about 25 meter. The profiles start at the helideck 10 m above sea level and terminate at the burst level of the balloons, normally at heights between 25 and 37 km.