Profiling the thermodynamic properties of the atmosphere with high spectral resolution infrared radiance measurements

High spectral resolution Interferometer Sounder (HIS) measurements are providing thermodynamic profiles of the atmosphere with high horizontal, temporal, and vertical resolution. Measurements from the NASA high flying ER-2 aircraft provide vertical cross-sections of the atmosphere, with 2 km horizontal resolution, from the aircraft altitude of 20 km down to the Earth´s surface or cloud level. Most recently, April 13, 1994, the thermodynamic cross-section of the southern Polar Vortex was observed with unprecedented resolution during a flight from Christchurch New Zealand (43°S) to the Antarctic Ice Shelf (68°S) as part of the Airborne Southern Hemisphere Ozone Experiment (ASHOE). The groundbased HIS, called the Atmospheric Emitted Radiance Interferometer (AERI), is operating continuously at DOE´s Atmospheric Radiance Measurement (ARM) site in Lament, Oklahoma. These data permit thermodynamic cross-sections of the planetary boundary layer (PBL) to be observed with ten minute time resolution. The temperature profile sensitivity in the lowest two kilometers is believed to be the best achievable using remote sensing techniques. The low level temperature inversion is distinctly evident in the transparent region of the aircraft spectrum as well as in the opaque region of the groundbased spectrum