Theoretical Determined Terahertz Attenuation in Snow and Sleet

Market demand for high-bandwidth wireless communication options in outdoor settings has pushed wireless communication systems towards higher frequency regimes. However, attenuation of wireless signals due to environmental factors such as atmospheric gases and particulates generally scales with increasing frequency, thereby limiting the functionality of such systems. Low-frequency THz radiation (.1 - 1 THz) has been identified as a suitable carrier range due to its reduced attenuation relative to higher frequencies and significant available bandwidth. Still, little is known about the attenuation of THz radiation in the presence of weather conditions such as snow and sleet. In this study, the attenuation of THz radiation by snow aggregates and sleet is investigated using the Mie approach for the scattering of electromagnetic radiation. Differences in attenuation spectra between rain, sleet, and dry snow are identified and the difficulty of measuring THz attenuation by dry snow aggregates is considered. In addition, it is suggested that water vapour may be the leading attenuator for instances of dry snowfall. Finally, the potential for THz radiation to be used in aircraft ice sensing systems is explored by analyzing THz backscattering calculations for various ice-crystal sizes.