Observing System Simulation Experiments (OSSEs) provide an effective means to evaluate the potential impact of a proposed observing system, as well as to determine tradeoffs in their design, and to evaluate data assimilation methodology. Great care must be taken to ensure realism of the OSSE's, and in the interpretation of OSSE results.

All of the OSSEs that have been conducted to date have demonstrated tremendous potential for space-based wind profile data to improve atmospheric analyses, forecasts, and research. This has been true for differing data assimilation systems, analysis methodology, and model resolutions. OSSEs have shown the impact of wind profile data to be only very slightly dependent on the magnitude of the random (uncorrelated) errors of the observations. OSSEs clearly show much greater potential for observations of the complete wind profile than for single-level wind data or observations of the boundary layer alone.

OSSEs are currently being conducted as a joint project between Simpson Weather Associates, and the NASA Goddard Laboratory for Atmospheres to determine the quantitative impact of space-based lidar wind observations in current and future operational and research data assimilation systems, the precise requirements for accuracy, coverage and resolution, the relative impact of proposed coherent and incoherent lidars, the redundancy of lidar with other observing systems, and the ability of adaptive targeting to maximize the impact of lidar (and other) data. At the conference, results from these OSSEs, relating to numerical weather prediction, precipitation forecasting, and hurricane track prediction will be presented.