Peculiarities of the lower thermosphere composition variations at high latitudes from the results of rocket experiments

An analysis of the results of more than 50 rocket experiments on the measurement of the thermosphere composition at 120-160 km height carried out during 1968-1989 (February, March) on the Heyss Island (80 deg 37 N 58 deg E) has been conducted. During the development of the magnetosphere substorm the decrease of O/N2, O /Ar ratios in the morning and evening sectors of the auroral oval and their increase in the polar cap take place. Correlation coefficients of O/N2 with Kp for the auroral oval zone and the polar cap correspondingly are equal to -0.8 and +0.6 at the 115 km height. The latter effect is attributed to the observed increase of O/N2, this corresponds to the thermosphere adiabatic cooling in the night sector of the polar cap, which evidently acts jointly with the vertical transport effects. (Author)