Oceanic refractivity gradients induce operational and security concerns of naval operations. Continuous passive characterization of refractive effects upon visible, IR, and radio/RADAR electromagnetic propagation through passive relatively inexpensive multiband IR camera observations is enabled with the apparatus and methods proposed herein. Passive remote sensing of profiles, structure, and gradients of refractivity, temperature, and water vapor in the troposphere can be obtained through multispectral observations, or alternatively, measurements at a number of observing elevation angles, or both. The methodology proposed herein is a new approach and utilizes both methods in heretofore unused infrared observations to maximize independent measurements and therefore skill, in obtaining said tropospheric structures. The system is capable of a very rapid, 30 Hz, frame rate of over 300,000 pixels of 0.04C infrared temperature resolution. This information is inverted mathematically into high vertical resolution tropospheric structure. The profile informations obtained can be utilized to model the refractivity environment in all EM wavebands, from low frequency radio through ultraviolet. The profile measurement skill greatly exceeds that of microwave radiometric methods of profiling.
Benefit: This passive technology can augment or replace active methods currently in use by the Navy to determine the refractive environment, including radiosondes and radar clutter and UAVs, and will be superior to atmospheric modeling methods currently in use. The apparatus and method developed herein are, with some further development, applicable to passive atmospheric temperature and water vapor profiling and wind finding aloft.
Keywords: Infrared imaging, Infrared imaging, evaporation duct, tropospheric temperature profile tropospheric water vapor profile, oceanic refractivity, Radar Ducting, Anomalous Propagation
