Impact assessment of prospective spaceborne Doppler wind lidar observation scenarios

Anticipating on the success of ADM-Aeolus there is a need to specify the wind observation requirements for the definition of an operational network of spaceborne Doppler wind lidars (DWL) in the post-ADM era, beyond 2012. As a first step, Sensitivity Observing System Experiments (SOSE) have been conducted to investigate the added value of various DWL scenarios in real events with bad forecasts. A database of cases covering the worst 2-d forecasts over Europe and North America for each season over the 1998-2004 period was used for this purpose. Considered DWL scenarios include (i) trains of the Aeolus-type instrument to increase the coverage of single wind components, (ii) a scenario having the same coverage as Aeolus but measuring the complete wind vector and (iii) a targeting scenario giving maximum coverage over the storm track regions. For the Northern Hemisphere extratropics it was found that a DWL network providing a geographically uniform sampling is more beneficial for numerical weather prediction (NWP) than a network providing larger but more localized improvements. A network of Aeolus-type satellites fulfils this goal. The added benefits of a second and third Aeolus in orbit are, respectively, 70 and 110% of the benefit of a single Aeolus DWL.