Based on the results of numerical experiments performed with general circulation models (GCMs), the Arctic region is expected to be sensitive to climatic change caused by increasing concentrations of atmospheric greenhouse gases. To improve the predictive capabilities of GCMs, it is essential to understand the mean state and variability of the Arctic atmosphere. Downwelling longwave radiance spectra contain information about atmospheric properties and their variability. Using downwelling radiance data from Atmospheric Emitted Radiance Interferometers (AERIs) at the SHEBA Ice Camp and the North Slope of Alaska/Adjacent Arctic Ocean ARM site at Point Barrow, Alaska, the monthly average radiance spectra for clear and cloudy skies are determined. The clear-sky spectra are partitioned into spectral bands that are dominated by emission from particular greenhouse gases, such as the transparent portion of the water vapor rotational band from 400 to 600 cm-1. In addition, the variability in the transparent portions of the longwave spectrum give insight into how clouds affect the surface radiation budget. Therfore, the spectral longwave cloud forcing at the surface is calculated by subtracting the average clear-sky radiance from the all-sky radiance. Higher-order statistical parameters are also examined to investigate the variability, on monthly time scales, of the longwave radiance spectrum