We made an experimental vicarious calibration of the Moderate Resolution Imaging Spectroradiometer (MODIS) Airborne Simulator (MAS) thermal infrared (TIR) channel data acquired in the field campaign near Mono Lake, Calif. on 10 March 1998 to demonstrate the advantage of using high-elevation sites in dry atmospheric conditions for vicarious calibration. With three lake-surface sites and one snow-field site, we estimated the MAS noise-equivalent temperature difference as 0.7-1.0°C for bands 30-32 in the 3.68-4.13µm region and 0.1-0.5°C for bands 42, 45, 46, and 48 in the 8-13.5µm region. This study shows that the MAS calibration error is within 0.4°C in the split-window channels (at 11 and 12µm) and larger in other TIR channels based on the MAS data over Mono Lake and in situ measurement data over the snow-field site.