Assessment of the ERA-Interim Winds Using High-Altitude Stratospheric Balloons

AbstractThis study focuses on the ability of ERA- Interimto represent wind variability in the middle atmosphere. The originality of the proposed approach is that wind measurements are deduced from the trajectories of zero-pressure balloonsthat can reach high-stratospheric altitudes. These balloonsare mainly used to carry large scientific payloads. The trajectories of balloonslaunched above Esrange, Sweden, and Teresina, Brazil, from 2000 to 2011 were used to deduce zonaland meridionalwind components (by considering the balloonas a perfect tracer at high altitude). Collected data cover several dynamical conditions associated with the winter and summer polar seasons and west and east phases of the quasi-biennial oscillationat the equator. Systematic comparisons between measurements and ERA- Interimdata were performed for the two horizontal wind components, as well as wind speed and wind directionin the [100, 2]-hPa pressure range to deduce biases between the model and balloonmeasurements as a funct...