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The earth's radiant energy budget is a balance between absorbed solar radiation and emitted Outgoing longwave radiation (OLR). For almost 50 years now, accurate, long term records of solar insolation, planetary albedo, and OLR have been collected to monitor climate change. This paper describes results of two closure studies: one tests how well a state of die art radiative model using satellite retrievals from Atmospheric Infrared Sounder (AIRS) reproduces clear sky observations of OLR obtained by the Clouds and the Earth's Radiant Energy System (CERES) broadband radiometer, and the other tests how well the AIRS retrievals input into the radiative model reproduces AIRS radiances. In both studies the methodologies were tested at the Department of Energy (DOE) Atmospheric Radiation Measurement (ARM) program site in the U.S. Southern Great Plains (SGP) then applied globally. The clear sky OLR comparisons were impressive; RRTM calculations agree with CERES observations to similar to 1 W/m(2) with an uncertainty of similar to 1 W/m(2) at SGP between September 2002 and February 2005 and globally (with some understood regional exceptions) for four study days. Clear sky global analyses as a function of the International Geosphere Biosphere Programme (IGBP) surface types quantified clear sky OLR agreements for exceptionally bad (desert and snow/ice) and good (ocean) regions. Obtaining cloud conditions in the necessary, form for radiative model calculations remains a formidable challenge but preliminary results are presented here. AIRS spectral analysis uncovered a persistent bias in the upper level water vapor reported by AIRS retrievals but no day/night bias necessary to explain the day/night bias seen in die OLR comparisons to CERES. We were also able to offer one of the few, albeit tentative, estimates of the error in the far infrared (a radiatively important but understudied spectral region) to be better than similar to 0.3% for clear skies.