Utility of the 4.6- to 4.9-um atmospheric window for remote sensing of background temperature

Abstract

A field measurement program was initiated to determine the utility of the 4.6- to 4.9-μm spectral region as a remote temperature sensing channel. A spectroradiometer (covering the 1.3- to 14-μm region) was used to determine effective surface temperatures of various natural objects both in the 4.6- to 4.9-μm and the commonly used 10.5- to 12.5-μm regions. Comparisons of the effective temperatures obtained from both short-range (30 to 300 m) and long-range (3 to 10 km) measurements are presented. For measurements at short ranges, the deduced effective temperature for each region wascompared with contact temperature measurement of the surface. For measurements over long ranges, the effective temperatures were compared after having accounted for path radiance effects. Accurate path radiance corrections were made from measurements over the tail region of the 4.3-μm CO₂ absorption band.