ADM-Aeolus: The first space-based high spectral resolution Doppler Wind Lidar

Abstract

The 'Living Planet Programme' of the European Space Agency (ESA) is gaining momentum. Six Earth Explorer missions are currently being implemented including ADM- Aeolus, ESA's Doppler Wind Lidar (DWL) mission. The Aeolus mission will demonstrate the capability of a space- borne high spectral resolution DWL to accurately measure wind profiles in the troposphere and the lower stratosphere (0- 30 km). The Mission thus addresses one of the main identified deficiencies of the current Global Observing System (GOS). From the backscattered frequency-shifted laser light it will be possible to obtain about 3,000 globally distributed horizontal line-of-sight (HLOS) wind profiles daily. The accuracy of the Aeolus winds, in cloud-free regions and above thick clouds, is expected to be comparable to that of radiosonde wind measurements. Additional geophysical products that will be retrieved from the Aeolus measurements are cloud and aerosol optical properties. Aeolus HLOS wind profiles will find wide application in Numerical Weather Prediction (NWP) and climate studies, improving the accuracy of numerical weather forecasting, advancing our understanding of tropical dynamics and processes relevant to climate variability and climate modelling. Impact experiments, assimilating synthetic Aeolus wind data into operational NWP models, have already been performed. One focus has been the forecast performance in regions known to be particularly sensitive to the accuracy of the initial conditions. The tentative results show that the largest benefits from Aeolus HLOS winds can be expected over the oceans and in the Tropics. In view of other lidar missions in space, the potential of a long-term database of cloud and aerosol optical properties is being studied. An additional topic is the potential benefit of wind profile observations in the lower stratosphere. Ground-based and airborne campaigns are being prepared for the validation of the Aeolus Airborne Demonstrator (A2D) - a high spectral resolution DWL instrument with technology very similar to Aeolus. This paper provides an overview of the Aeolus mission, the science and application activities being performed in support of the mission and the potential benefit of such observations in a wider context.