Unmanned Aircraft Systems (UAS) are a developing technology which have the potential to provide unique observations of the atmosphere within the coming decade. These aircraft can be deployed in remote data poor locations to complement existing satellite and conventional observations.

An Observing System Simulation Experiment (OSSE) is undertaken to evaluate the potential forecast impact of observations from the UAS and to guide the planning and deployment of UAS missions. This OSSE is part of a larger Joint OSSE effort between multiple agencies, including ECMWF, NCEP, NASA, JCSDA, ESRL, and others. Global OSSE experiments will examine the potential for UAS observations over the Arctic and Pacific regions using a global forecast model and global Nature Run. Regional OSSE experiments will include UAS deployment into tropical cyclones. Details of the calibration of the global OSSE, characteristics of the global Nature Run, and generation of synthetic UAS observations will be presented.