CopterSonde-SWX: Development of a UAS-based Vertical Atmospheric Profiler for Severe Weather

Abstract. Growing demand for high spatiotemporal resolution observations in the planetary boundary layer (PBL) has driven the development of affordable, small uncrewed aircraft systems (UAS) technology to fill critical observational gaps and support improved understanding and future assimilation into prediction models. This work presents the CopterSonde-SWX (CSWX), an in-situ UAS vertical profiler that combines a high-thrust tilted-body airframe, a wind-vane flight mode for sampling undisturbed air, and a shielded actively ventilated sensor scoop to acquire thermodynamic and full 3D wind vectors without dedicated anemometers. Through a series of flow simulations and intercomparison field campaigns, including colocated flights with its predecessor (CS3D), Doppler wind lidars, and radiosondes, the CSWX demonstrated inter-sensor temperature uniformity within ± 0.2 °C across variable solar and wind regimes and achieved LESO-based wind retrieval RMSEs of 0.49 m s^-1 (vertical) and 1.03 m s^-1 (horizontal). In a nocturnal low-level jet case, the CSWX sustained winds up to ∼ 24 m s^-1 at 520 m (versus the CS3D's 20 m s^-1 limit at ∼ 275 m), with polynomial fits projecting a safe maximum wind tolerance of 29.5 m s^-1 while retaining sufficient battery energy margin for safe return. These results support the CSWX as a resilient, high-fidelity platform for atmospheric profiling, advancing the transition from a research prototype to an operational instrument. Even though the CopterSonde is an experimental design, this work may serve as a guideline to define future standards for WxUAS development.