Data assessments using simulation experiments are able to provide a quantitative evaluation of future observing systems and instruments. These experiments are known as Observing System Simulation Experiments (OSSE). There are many motivations for OSSEs but the most important motivation for OSSEs regards estimating the potential impact of proposed new observation types.

OSSEs are very labor intensive project. It has been realized that preparation of NR including evaluation, simulation of observation, distribution of the data, consumes a significant amount of effort. Therefore, the larger cost of the instruments is involved, the more OSSEs become valuable. Since space based Doppler Wind Lidar (DWL) is one of the most expensive instruments, many OSSEs has been conducted to evaluate their impact.

OSSEs are very labor intensive projects. It has been realized that the preparation consumes a significant amount of effort. This includes evaluation of the Nature Run (proxi true atmosphere), simulation of observations form it, its distribution, calibration of simulated observation. In Joint OSSEs, a common NRs will by used by the various data assimilation systems at many institutes. The first three Joint OSSE NRs have been produced by the European Center for Medium-Range FOrecasts. In Joint OSSE, KNMI, SWA, and NASA are coordinating effort to evaluating various type of DWL under various scenarios.

OSSE to evaluate DWL has been conducted by NCEP using lower resolution NR and old data assimilation system (SSI). However, data impacts depends on many factors: data assimilation system, error assignments, model resolution, verification method and more. The evaluation same simulated DWL will be repeated with new data assimilation system (GSI) which will be used in Joint OSSE project.