资源环境科技发展态势分析平台

Abstract. Current climate models have difficulty representing realistic wave-mean flow interactions, partly because the contribution from waves with fine-vertical scales is poorly known. There are few direct observations of these waves and most models have difficulty resolving them. This observational challenge cannot be addressed by satellite or sparse ground-based methods. The Strateole-2 long-duration stratospheric superpressure balloons that drift with the horizontal wind on constant density surfaces provide a unique platform for wave observations across a broad range of spatial and temporal scales. For the first time, balloon-borne Global Navigation Satellite System (GNSS) radio occultation (RO) is used to provide high vertical resolution equatorial wave observations. By tracking navigation signal refractive delays from GPS satellites near the horizon, 40–50 temperature profiles were retrieved daily, from balloon flight altitude (∼20 km) down to 6–8 km altitude, forming an orthogonal pattern of observations over a broad area (±400–500 km) surrounding the flight track. The refractivity profiles show an excellent agreement of better than 0.2 % with co-located radiosonde, spaceborne COSMIC-2 RO and reanalysis products. The 200–500 m vertical resolution and consecutive sampling in time and space make it possible to extract properties of Kelvin waves to shorter period gravity waves with vertical wavelengths as short as 2–3 km. A short dataset from the extra Galileo and GLONASS constellations demonstrates the feasibility to nearly double the sampling density in planned follow-on campaigns. The results will contribute to improved estimates of momentum forces for wave driving of the Quasi-biennial Oscillation (QBO) and improved QBO representation in models, and illustrate the importance of measuring intrinsic period in the Lagrangian reference frame.