Airborne Lidar measurements of wind profiles during the MAGIC-2021 campaign

Abstract. Wind is an essential physical variable in atmospheric physics, and airborne Doppler lidars are valuable tools for profiling wind fields over wide areas. The paper reports on wind measurements performed with an airborne 1.5 µm coherent Doppler Lidar, during a campaign called MAGIC (Monitoring of Atmospheric composition and Greenhouse gases through multi-Instrument Campaigns) that took place in summer 2021 in France and in the Arctic. Vertical profiles of the horizontal wind (u and v components) are obtained with 150 m vertical resolution and a typical horizontal resolution of 2.5 km. Continuous wind profiling capability over vertical ranges up to 7.5 km is demonstrated. Two wind products are derived and compared, depending of the method used to correct for the aircraft speed. LGE-based wind product (Lidar Ground Echo) derives the aircraft speed from the Doppler shift measured by the lidar on the ground surface. FTI-based wind product (Flight Test Instrumentation) uses aircraft speed measurements by the navigation instruments. Through examples of lidar measurements realized during the campaign, advantages and limitations of LGE-based and FTI-based wind profiles are discussed. The LGE technique performs better over land and under clear weather, but the FTI technique, being independent of ground visibility and surface nature, is more generally usable. Yet it is found to exhibit some excess noise in the range of +0.6 to +0.8 m.s^‑1 in standard deviation along zonal and meridional wind components, attributed to aircraft random vibrations. Lidar wind profiles are compared to radiosonde measurements and are shown to agree within an average standard deviation of 1.2 m.s^‑1 in magnitude, over three datasets. They are also compared with independent wind data provided by the ECMWF Integrated Forecast System (IFS cycle 41r2). Both data sets agree within residual standard deviations in the range of 1.3–2 m.s^‑1 for zonal and meridional components, over six different flights (~21 hours of measurements). This airborne lidar appears as a promising tool for future scientific campaigns dedicated to climate modelling and atmospheric dynamics.