From AGU highlights, interesting, but readers should note that this is one point on Earth in Chile, not a summation of the atmospheric absorption, emission, and transmission of infrared radiation for the entire globe.
For first time, entire thermal infrared spectrum observed
The driving mechanism of the greenhouse effect, and the underpinning of modern anthropogenic warming, is the absorption, emission, and transmission of infrared radiation by atmospheric gases. The heat-trapping ability of a gas depends on its chemical composition, and each type of gas absorbs infrared radiation of different energies. The amount of infrared radiation that escapes into space depends on the net effect of the myriad gases in the atmosphere, with water vapor being the primary gaseous absorber of infrared radiation.
Water vapor absorbs a wide range of infrared radiation, masking the effects of other gases. In fact, in many spectral regions (or infrared radiation energy bands), water vapor is so strongly absorbing that it makes testing the accuracy of infrared radiation absorption parameterizations used in general circulation models difficult.
To surmount this obstacle, Turner et al. headed to a 5.3-kilometer (3.3 miles) altitude site in the Atacama Desert in northern Chile, where the air is extremely dry. Using a broad suite of spectroscopic equipment, they produce the first ground-based measurement of the entire atmospheric infrared radiation absorption spectrum—from 3.3 to 1000 micrometers—including spectral regions that are usually obscured by strong water vapor absorption and emission. Though the data collected will likely be valuable for a broad range of uses, the authors use their measurements to verify the water vapor absorption parameterizations used in the current generation of climate models.
Geophysical Research Letters,doi:10.1029/2012GL051542, 2012
“Ground-based high spectral resolution observations of the entire terrestrial spectrum under extremely dry conditions”
A field experiment was conducted in northern Chile at an altitude of 5.3 km to evaluate the accuracy of line-by-line radiative transfer models in regions of the spectrum that are typically opaque at sea level due to strong water vapor absorption. A suite of spectrally resolved radiance instruments collected simultaneous observations that, for the first time ever, spanned the entire terrestrial thermal spectrum (i.e., from 10 to 3000 cm−1, or 1000 to 3.3 μm). These radiance observations, together with collocated water vapor and temperature profiles, are used to provide an initial evaluation of the accuracy of water vapor absorption in the far-infrared of two line-by-line radiative transfer models. These initial results suggest that the more recent of the two models is more accurate in the strongly absorbing water vapor pure rotation band. This result supports the validity of the Turner et al. (2012) study that demonstrated that the use of the more recent water vapor absorption model in climate simulations resulted in significant radiative and dynamical changes in the simulation relative to the older water vapor model.
UPDATE: The full paper is here (thanks to Leif Svalgaard)