The impact of the vertical distribution of tropospheric water vapor on the cloud-free downward, broadband thermal-infrared irradiance (FTIR) was quantified using observations in the Central Arctic North of 85°N collected during the Arctic winter. The water vapor profiles were measured with a temporal resolution of 30 s by a Raman lidar. The observations revealed maximum values of integrated water vapor (IWV) contents of 3.6 kg m-2.  Seven measurement cases of several hours duration of slowly changing air masses were examined. Furthermore, 53 rather short-term (10 minutes) measurement cases were studied. The temporal evolution of the slowly changing air masses revealed a linear relationship between FTIR and IWV with slopes between 7.17 and 12.95 W kg-1 and a coefficient of determination larger than 0.95 for most of the selected cases. The slopes and the ordinate-intercepts showed a dependence on the water-vapor-weighted mean temperature (representative temperature of the water vapor distribution). The temperature determined with the Stefan-Boltzmann law from FTIR correlated with the representative temperature with a coefficient of determination of 0.92. The analysis of 53 independent short-term observations of different air masses confirmed the linear relationship between FTIR and IWV at wintertime cloud-free conditions in the Arctic (coefficient of determination of 0.75, slope of 19.95 W kg-1, ordinate-intercept of 107.22 W m-2).