Title: Toward Direct Measurements of Earth's Far-Infrared (far-IR)
Presenting Author: Martin Mlynczak
Organization: NASA LaRC

Abstract:
The past 15 years have seen a tremendous advance in the ability to calibrate, measure, and understand spectral radiances and fluxes at the top of the atmosphere, within the atmosphere, and at Earth's surface. Most notably, the importance of direct measurements of Earth's far-infrared (far-IR) spectrum has become widely recognized. The far-IR contains approximately one-half of the Earth's outgoing infrared radiation and greenhouse effect. Earth's troposphere cools to space almost exclusively in the far-IR. Cirrus clouds also have a strong radiative effect in the far-IR. Spectral fingerprints of climate change are manifest in the far-IR. Consequently, measurements of the top-of-atmosphere far-IR spectrum are a critical component of future climate missions. Measurements of spectral fluxes within the atmosphere are seen as essential for validating climate models and reducing major uncertainties in climate forcing. Rigorous calibration to international standards is also recognized as an essential part of any new mission measuring climate change. NASA ESTO has developed the Far-Infrared Spectroscopy of the Troposphere (FIRST) and In-situ Net Flux within the Atmosphere of the Earth (INFLAME) instruments to achieve accurate measurement of infrared and far-IR spectra. We will review these technologies, focusing on measurements and current understanding of the atmosphere's far-IR emission with respect to calibration and modeling uncertainties. We will also outline the path forward to making these key measurements from orbiting satellites.