Validation of Aeolus satellite wind observations with aircraft-derived wind data and the ECMWF NWP model for an enhanced understanding of atmospheric dynamics

Abstract

Launched on August 22th of 2018, the Atmospheric Dynamics Mission - Aeolus of the European Space Agency (ESA) carries a direct detection Doppler Wind Lidar (DWL) to measure wind profiles in the atmosphere from space. The primary product of this Earth observation satellite is the measurement of profiles of the horizontally projected line-of-sight (HLOS) wind component, resulting into a single wind component measurement rather than the complete wind vector. The main motivation of the Aeolus mission is to reduce the deficiency in the current global coverage of wind observations, as part of the current Global Observing System (GOS) of the World Meteorological Organization (WMO). Aeolus is a next step in the aim for a homogeneous spatial and temporal global network of wind observations.

In this study, HLOS wind observations of Aeolus have been validated with independent and high-resolution aircraft-derived Mode-S EHS wind observations, together with the Numerical Weather Prediction (NWP) model of the European Centre for Medium-Range Weather Forecasts (ECMWF). Validation is a challenge for a unique instrument which is still in its commissioning phase, meaning that observed winds have not yet been well-calibrated, hence not yet suitable for operational use in NWP. Nevertheless, the main validation results are very promising ; demonstrating a high agreement between Aeolus, Mode-S EHS and ECMWF with correlation values exceeding 0.9. The known systematic, and slowly drifting over time, bias in the order of 2 m/s is observed and confirmed from standard statistics as well as from the more advanced triple collocation technique.