A completely automatic chemiluminescent instrument has been developed for in situ measurements of NO in the stratosphere. Signal intensity is linear in NO. Typical responsivity at 21.3 km is 1860 counts/sec ppbv. With a 1 sec measuring time constant, the detection limit as determined by noise is 0.03 ppbv. The instrument has been flown from balloon platforms to 30.8 km and from aircraft platforms between 12.2. and 18.3 km.

Comparison is made between the results obtained from modifications to a state-of-the-art radiation code and bow shock uv radiation data obtained from recent flight experiments. Initial predictions of the radiation did not yield satisfactory comparison with the first flight experiment flown at 3.5 km/s between altitudes of 40-70 km, despite improvements to the original flow model. It is found that characterizing the NO excited state population with the translational temperature, rather than the vibrational temperature, yields better comparison to the flight data. Comparison of bow shock data from the second flight, flown at 5.1 km/s at altitudes of 70-90 km, shows that improvements in either flow or radiation modeling are still needed, particularly at high altitudes.

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