ADM-Aeolus CAL/VAL Preparations
Straume, Anne Grete¹; Ingmann, P.¹; Schuettemeyer, Dirk¹; LeRille, Olivier¹; Nett, Herbert¹; de Bruin, Frank¹; Elfving, Anders¹; Lengert, Wolfgang²; Bojkov, Bojan²; Dehn, Angelika²; Casadio, Stefano^3
1ESA, NETHERLANDS; ²ESA, ITALY; ³SERCO, ITALY

The European Space Agency is developing a direct detection Doppler Wind Lidar to observe wind profiles from space, as part of its Earth explorer programme. The Atmospheric LAser Doppler INstrument (ALADIN), on-board the ADM-Aeolus satellite, is a pulsed UV Lidar with high spectral resolution capability. It shall deliver single line-of-sight wind measurements from 24 vertical layers (0 to 30 km) from each of its two channels; one molecular (clear air) and one particle (aerosol and cloud backscatter) channel. ALADIN will measure the zonal component of the wind field in clear and particle-rich air (aerosol layers and transparent clouds), and down to the top of optically dense clouds. In addition to the wind profiles, ADM-Aeolus will also deliver cloud and aerosol related information such as height profiles of backscatter and extinction coefficients, scattering ratios and Lidar ratios. From these parameters further products can be derived, such as cloud-top height, multi-layer clouds and aerosol stratification, cloud and aerosol optical depths (integrated light-extinction profiles), and some information on cloud/aerosol type (Lidar ratio). The satellite will fly in a polar dusk/dawn orbit, providing a global coverage of ~16 orbits per day. The wind measurements (Level 1b) will be delivered near-real-time (NRT) together with a stand-alone Level 1-2 algorithm and will be effectively assimilated into operational numerical weather prediction (NWP) models. The cloud and aerosol related products will be provided off-line. In 2007, ESA released an Announcement of Opportunity calling for Calibration and Validation (CAL/VAL) proposals for ADM-Aeolus. 16 proposals were received world-wide, including a number of proposals being a composition of joint national efforts. Ground-based and airborne CAL/VAL activities were proposed including wind and other atmospheric sensing systems as well as proposals for Aeolus measurement assimilation and product monitoring. Since 2007, the Aeolus project has faced a number of delays due to challenges faced in the hardware development. It is therefore planned to launch a delta-AO call with the following objectives; (i) to allow for a reassurance of the availability of already submitted proposals, (ii) an opportunity for the teams to update their original proposal and cal/val strategies, and (iii) to invite new groups to participate. The delta call is planned to be announced in late fall 2013, after the finalization of the Aeolus laser qualification campaign. A CAL/VAL plan for Aeolus was established in 2006 and updated with inputs from the feedback from the 2007 AO call. This plan is being updated and will be presented. Also, the information for the planning and procedure of the upcoming Aeolus delta-call will be presented together with the planning for the pre and post-launch CAL/VAL preparations and efforts. Figure: An example of the Aeolus orbit, pointing and sampling characteristics