Long-path high-resolution field measurements of absolute transmission in the 3.5- to 4.0-microm atmospheric window.

An example of high-resolution (0.08 cm(-1)), absolute transmission spectra of a 5-km atmospheric path is presented. Precise transmission and wavenumber calibration of the spectra were obtained from infrared laser extinction measurements. A comparison of these spectra to line-by-line calculations shows excellent agreement in the spectral region between 2480 and 2800 cm(-1) (3.57 to 4.03 microm).