RAPID MEASUREMENT OF N2+ ROTATIONAL TEMPERATURES IN AURORA

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Abstract
A description is given of a photoelectric "temperature photometer" which gives a temperature reading from aurora in about one second. It uses two narrowband interference filters to measure the intensity in two parts of the bright N2+ band at 3914 Å, and a third to allow a background measurement. The reading is presented on a meter and is independent of the auroral intensity over a wide range. Observations of aurora have permitted construction of a temperature profile for the atmosphere from 95 to 170 km, showing a gradient of 6.0° K/km. A lowest temperature of 140 ± 20° K was observed for a period of several minutes. Diffuse surfaces appear from their temperatures to occur anywhere from 100 to 160 km.