Temperature-dependent optical constants of water in the thermal infrared derived from data archaeology

This paper describes a data archaeology and rescue of temperature-dependent thermal infrared (IR) optical constants for liquid water from previously published works. The data rescue is based upon digitization of a figure published by Pinkley et al. [J. Opt. Soc. Am. 67, 494 (1977)], which showed ratios of laboratory measured spectral reflectances taken at 4 different temperatures (1, 16, 39, and 50 °C) with those measured previously at 27°C. Using our digitization of these data, we perform Kramers-Kronig analyses to derive temperature-dependent optical constants for existing standard datasets taken at room temperatures for the entire thermal IR spectrum. These datasets are of interest for the accurate modeling of thermal IR surface emissivity and reflectance over the range of global surface temperatures.