N2, O, He, Ar Densities

Description

This data set generated at the University Bonn contains the neutral density data observed by the ESRO 4 Gas Analyzer instrument. Each logical record includes 13 words: day number, time of day, altitude, latitude, longitude, local solar time, L-value, invariant latitude, magnetic local time, and the number densities (in cm-3) of N2, O, Ar, and He. The sensitivity threshold of the gas analyzer is approximately 6*10^3 cm-3. Spin modulation effects can be observed in the data from an apparent offset of about one degree from the spin axis. A correction factor of 2.5 has been applied to the He data in this data set as a result of intercomparisons with neutral densities measured by other mass spectrometers (Trinks et al., Intercomparison of neutral composition measurements from the satellites ESRO 4, AEROS-A, -B and AE-C, J. Geophys. Res. 82, 1261, 1977; von Zahn et al., ESRO 4 model of global thermospheric composition and temperatures during times of low solar activity, Geophys. Res. Lett. 4, 33, 1977).