Comparison of neutral temperatures inferred from instruments on the AE‐C satellite

Four determinations of neutral thermospheric temperature from data taken with instruments aboard the AE‐C spacecraft have been compared during the circular orbit phase in late December 1974 and January 1975 when the satellite altitude was near 260 km. These temperatures are found to be in overall agreement to within about 10% during periods of low magnetic activity (Ap < 12). The methods are based on: (1) analysis of the satellite spin modulation of N 2 density; (2) analysis of the ion temperature; (3) and (4) the calculation of the temperature needed to match measured N 2 and Ar densities assuming fixed boundary conditions at 120 km. Systematic differences are observed such that the ‘argon temperature’ increases the most from winter to summer and ion temperature the least.