The Atmospheric Dynamics Mission Aeolus (ADM-Aeolus) satellite was launched on 22nd August 2018 as part of ESA's Living Planet Programme. Using a laser-based measurement technique, Aeolus provided accurate, global measurements of winds from Earth’s surface up to 30 km altitude, from pole to pole.

The wind profiles provided by Aeolus are not only global, but they also have a vertical resolution fine enough to allow scientists to build more detailed models of atmospheric dynamics, and thus improve weather forecast and climate models. This knowledge will aid our understanding of the transport of energy, water, aerosols and atmospheric gases – including air pollutants. Aeolus’ wind profiles will also provide data to help understand weather drivers and modulators, such as the El- Niño Southern Oscillation (ENSO) phenomena.

The single Earth observation instrument carried by Aeolus was the Atmospheric Laser Doppler Instrument (ALADIN), a Doppler Lidar operating in the near ultra-violet (355 nm) spectral region. ALADIN is an active remote sensing instrument, which means it generates its own source of UV electromagnetic radiation which it then uses to probe our atmosphere. Specifically, ALADIN generates UV laser pulses and directs them toward the Earth, measuring the Doppler shift of the returned signal scattered back towards the satellite by the material present at different levels of our atmosphere. One of ALADIN’s receiving spectrometers measures atmospheric backscatter from aerosols and water droplets, whilst the other measures that from (the far smaller) air molecules. The Doppler shift of the backscattered signal is then analysed with respect to the frequency of the transmitted laser pulse and as a function of time (returns taking longer to be received come from a lower level in the atmosphere – further away from the satellite). In this way, the data from ALADIN makes it possible to determine the wind at various altitudes above the surface.

In this video, we hear from Aeolus mission Scientist Anne Grete Straume, who will explain in more detail how the Aeolus mission measured global winds.

The video for this topic was originally produced in 2019. Aeolus has now been decomissioned after orbiting around Earth for four years, eleven months and six days, since its launch in August 2018. For further information, you can visit the Aeolus mission page.

Featured Educator

• Dr Anne Grete Straume, Aeolus Mission Scientist, ESA

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