The NO 5.3 μm radiation and associated atmospheric cooling rates

The fundamental vibrational-rotation band emission from NO around 5.3 μm (v=1-v=0) in the thermosphere is generally produced by (1) solar pumping, (2) Earth shine pumping, (3) the inelastic collisions of NO(v=0) with O,(4) the reaction of N(²D) with O₂, and (5) the reactions of N(⁴S) with O₂. The relative importance of each source depends on the geophysical conditions (i.e. nighttime, sunlit, or aurora) and location (i.e. latitude, or altitude). Of the five sources of NO(v=1) considered, the inelastic collisions of NO(v=0) with O are an effective atmospheric cooling mechanism in the lower thermosphere. This paper discusses the utility and limitations of NO 5.3 μm radiance measurements from space such as those obtained by SABER/TIMED for the determination of associated atmospheric cooling rates under various geophysical conditions.