Upper Atmosphere Wind and Temperature Measurements Using a Small, Static, Gas-Filtered Earth Limb Imager—Modern GPS, ADCS, and FPAs Make It Possible.

Wind and Temperature observations are arguably the most valuable measurements for neutral atmosphere research and forecasting. We review a technique, invented 7 years ago that performs these measurements day and night from 20-200+ km with 10 km along track resolution. It uses the Doppler shift induced by the spacecraft velocity to produce a spectral scan of atmospheric emission by a gas filter. The spectral scan is naturally produced as the scene passes through the sensor field-of-view that is observing the earth limb perpendicular to the spacecraft velocity vector. No scanning mechanism is required. This Doppler Wind and Temperature Sensor (DWTS) is a simple static IR camera. The resulting measurements have remarkable S/N and can be used to infer wind (both vectors simultaneously), neutral temperature and the gas cell filter condition, all without radiance calibration. We conclude with a vision of how DWTS fits into a next generation weather observation vision we call METNET.