Solar occultation observations of the Martian atmosphere in the ranges of 2–4 and 4–8 keV measured by phobos 2

Occulations of the Martian atmosphere measured during two solar flare events are studied to obtain density and temperature profiles in the altitude range from 80 to 130 km. The temperature profile observed at enhanced solar activity ( F 10.7cm = 201) demonstrates a temperature wave with an amplitude of 15 K and a length of 20 km similar to those observed by the Viking probes. The profile measured at very high solar activity ( F 10.7cm = 257) shows a steep increase of temperature in the range of 110–125 km which is caused by the downward heat flux and results in a solar EUV heating efficiency of ϵ = 0.1. The structure of this profile between 85 and 110 km may be explained by a temperature wave and/ or eddy cooling and turbulent heating of the atmosphere.