ECMWF assesses pioneering Aeolus wind data

Lars Isaksen
Michael Rennie


ECMWF has begun to process wind profile data from the ground-breaking Aeolus satellite launched on 22 August 2018. First comparisons with ECMWF model data are very encouraging. ECMWF now expects to start assimilating Aeolus data operationally in 2019.

ECMWF is contracted by the European Space Agency (ESA) to produce Aeolus wind products suitable for use in numerical weather prediction. As the Level-2 Meteorological Processing Facility, it will produce wind products and auxiliary meteorological data products for ESA in an operational manner during the mission’s lifetime. The Centre started to process Aeolus data within two weeks of the satellite’s launch. Just three days after the instrument was switched on, Aeolus was delivering data showing clear features of the wind. Within two weeks, realistic wind profiles as shown in the figure could be produced from the data.

First wind data from the Aeolus satellite. These wind profile data from 4 to 5 September 2018 cover three quarters of an orbit from the Arctic (left) to the tropics and the Antarctic (middle) and back to the tropics (right). There are no data in the black areas either because the ground is elevated (green line) or because of the presence of thick clouds which the Aeolus laser cannot penetrate.

Aeolus is an ESA Earth Explorer satellite mission with an expected lifetime of three years. The polar-orbiting satellite uses ground-breaking laser technology to obtain vertical wind profiles in the troposphere and lower stratosphere. It aims an ultraviolet laser into the atmosphere and detects the Doppler-shift of the backscattered light from both molecules (clear air) and particles (clouds/aerosols). Since very few wind profile measurements are available from other observing systems, Aeolus could bring a significant improvement in the quality of weather forecasts around the globe. The expectation is that the near-real-time wind information it provides will lead to much-improved analyses of the state of the atmosphere, especially in the tropics, with a major impact on forecast quality in the tropics and a smaller but still important impact in the extratropics.