Infrared All-Sky Imaging System for Measurement of Cloud Properties

Effective utiliization of Air Force electro-optical systems requires precise measurement of cloud properties with high spatial and temporal resolution. Radiative interactions of clouds with the thermal and optical emissions of targets and with the ambient background radiation field affect the ability to detect and track targets traveling through cloud filled skies. The results of the FIRE program concerning the sensitivity of IRST systems show how important the effects of cloud backgrounds can be. The proposed research will examine the degree to which passive infrared remote sensing technology can determine the microphysical and optical properties of clouds. We will design an all-sky imaging system that measures cloud thermal radiances at a few closely spaced wavelengths within each of the 305u and 10-12u atmospheric windows to determine cloud temperatures and IR emmissivities and other microphysical properties. Polarization measurements of scattered solar IR will give information about the ice structure of clouds.