Measurement of spectral transmission through snow from SWIR to LWIR

The dependence of IR transmission on specific weather conditions is important to understanding the performance and limitations of IR sensor systems in such conditions. In this work, atmospheric transmission spectra were recorded in snowy conditions in Alvdalen, Sweden along with simultaneous measurements of meteorological data. MODTRAN was used to model the predicted transmission spectra to compare with and verify the experimental data. The apparent path averaged extinction was calculated and plotted against precipitation rate, relative humidity and wind speed for a range of wavelengths. Weak positive correlations were found between all three meteorological parameters and measured extinction. The data showed slightly stronger correlations between meteorological variables and extinction for longer wavelengths, however further data collection in a wider range of conditions is needed to confirm this result.