Measurement of the neutral composition of the lower thermosphere above Fort Churchill by rocket-borne mass spectrometer

The neutral atmospheric composition above Fort Churchill, Canada (59°N, 94°W), was measured by mass spectrometers in two rocket flights at 0835 CST on February 4 and 6, 1969. A quantitative measure for the extent of agreement with static diffusive equilibrium is introduced, and substantial agreement with profiles predicted when static diffusive equilibrium was assumed is found for all constituents including helium. A sensitive search for atomic nitrogen yielded upper limits of a few per cent for one flight and of 0.2% for the other.