Current status of the Faraday Filter-Based Spectrometer to Measure Sodium Nightglow D2/D1 Intensity Ratios
Abstract
Slanger et al. (2005) first observed an annual variation in the sodium nightglow intensity ratio of D2 (589.158 nm) to D1 (589.756 nm) emissions. Their proposed modified Chapman mechanism invokes two competing chemical pathways, showing that the intensity ratio is related to the concentration ratio of atomic oxygen [O] to molecular oxygen [O2]. This paper will describe laboratory and field testing of the compact, Faraday filter-based spectrometer to measure the D2/D1 intensity ratio of the nightglow--particularly results of our study on the effects of sky background on ratio measurements. This method also permits determination of the fractional contributions of the two chemical pathways to test the validity of the modified Chapman mechanism. Since delineation of the two chemical pathways requires a spectral resolution of 0.0002 nm, this is not possible with any other existing instrument.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2009
- Bibcode:
- 2009AGUFMSA23A1461H
- Keywords:
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- 0310 ATMOSPHERIC COMPOSITION AND STRUCTURE / Airglow and aurora;
- 0340 ATMOSPHERIC COMPOSITION AND STRUCTURE / Middle atmosphere: composition and chemistry