Absorption by water vapor in the far-infrared (wavelengths between 15 and 100 µm) governs the radiative heating of the mid-to-upper troposphere.  Therefore, errors in the modeled water vapor absorption impact the radiative divergence at these levels, which could potentially impact the general circulation of the Earth's atmosphere.  Two recent field experiments, using newly developed instrumentation, have provided a wealth of new data, resulting in an improved understanding of the magnitude of the water vapor absorption in this spectral region.  This presentation will present the details and results of these field experiments, and illustrate the impact of the results on a Global Climate Model simulation.