Validation of Airborne Thermal Infrared Remote Sensing of Snow Surface Temperature in the Upper Tuolumne Watershed, Yosemite National Park, California, USA

Here we present 5-m spatial resolution thermal infrared measurements of snow surface temperature collected by a small airplane flying over the upper Tuolumne watershed in Yosemite National Park in February, 2016. The plane captured spatial and temporal variations in the temperature of the snow’s surface, while concurrent ground measurements provided a reference point to evaluate the aerial measurements’ accuracy. Thermal infrared measurements provide a diagnostic tool used to assess model representation of many key processes, including snowmelt rates, sensible and latent heat fluxes, and longwave radiation. Comparisons between airborne observations and ground based measurements indicate airborne observations reliably quantify snow surface temperature to within approximately 2°C. This difference indicates a considerable reduction in uncertainty when compared to modeled snow surface temperature. By correcting ground-based thermal infrared measurements for view angle snow surface emissivity effects, differences between ground based and airborne observations are reduced to approximately 1.5°C. (KEYWORDS:  surface temperature, remote sensing, ground validation, infrared)