Thermospheric structure associated with discrete levels of auroral activity

概要

論文の詳細を見る
A time-dependent calculation has been done to study dynamical and compositional structure of the thermosphere associated with discrete levels of auroral activity. The auroral activity level is given in terms of estimates of hemispheric power input due to particle precipitations. Heat and momentum input originated from the magnetosphere is estimated by using an empirical model constructed from the two data bases of the precipitating particles monitored by the TIROS/NOAA satellites and the ionospheric convection electric field measured by the Millstone Hill Incoherent Scatter Radar. The main results are summarized as follows : At the level of moderate auroral activity, the horizontal and vertical winds are very weak. High-latitude heating is in the same order of magnitude as the solar EUV/UV heating. These two heatings cause a temperature minimum at mid-latitudes. The latitudinal variation of the mean molecular mass is small. At the highest level of auroral activity, the strong equatorward wind is excited associated with the high-latitude upward wind. A temperature bulge appears at high latitudes and the mean molecular mass increases due to the upwelling of the molecular-rich air. The dynamical response to the auroral activity is faster than the thermal and compositional response. The thermal response depends significantly on the radiative cooling by nitric oxide.
国立極地研究所の論文