Wide-band spectrally resolved measurement of the Earth's up-welling radiation with the REFIR-PAD spectroradiometer

The REFIR-PAD (Radiation Explorer in the Far InfraRed - Prototype for Applications and Development) Fourier transform spectroradiometer has successfully performed, at the end of June, 2005, a stratospheric balloon flight from Teresina, Brazil. The instrument has provided 8 hours worth of nadir-looking spectra acquired with a resolution of 0.5 cm-1 in the 100 to 1400 cm-1 spectral range, thus covering both the far-infrared range, containing the radiative signature of the upper tropospheric water vapour, and the better-known mid-infrared range, which provides validation with existing instruments. From the analysis of the calibrated spectra we obtain valuable information on the contribution to the Earth's outgoing long-wave radiation of water, both in the vapour and cloud form, in a region of the atmosphere, the upper-troposphere/lower-stratosphere, in which this contribution has a critical role.