Atmospheric Characterization for Directed Energy Applications

Atmospheric refractive index fluctuations directly impact the propagation of laser beams through the atmosphere. A key parameter of interest to be directly acquired or derived from atmospheric measurements is the refractive index structure parameter CN2. Atmospheric refractive index, and therefore CN2, can theoretically be derived as a function of temperature, humidity, and pressure measurements, but there are significant problems associated with such an approach. To better meet the measurement needs, a suite of three sondes will be developed: a new type of thermosonde, a refractive index sonde, and a full-featured sonde that incorporates those functions plus other meteorological measurements. The former two sondes will return high-speed data that can be used to compute CN2 and the related parameter CT2, respectively. The full-featured sonde will return all of that data plus other relevant meteorological and optical parameters. Data from these sondes will be integrated with atmospheric models to enable forecasts of these parameters and to support the development of decision-making aids based on the models. In Phase I, the new thermosonde will be developed and demonstrated, the other two sondes will be designed, and suitable forecast models will be identified for use with the sonde data.