Further measurements of thermospheric response to joule heating

Abstract Okano et al. (1985, Planet. Space Sci. 33 , 841) studied the Joule heating produced by auroral electrojets and the subsequent thermospheric temperature increase for an isolated magnetic substorm that occurred on 2 September 1978 (U.T.). As an addendum to their paper, we report here the meridional wind measurements made at Albany (42.68°N, 73.82°W; geomagnetic latitude 54.3°), New York, on the same night and show how this additional information would provide a more complete picture of the mid-latitude thermospheric response to the Joule heating produced by the dissipation of auroral electrojet currents. The results indicate that the neutral temperatures and the meridional wind velocities determined from the ground-based optical technique responded to the intensification of the westward auroral electrojet somewhat differently; the temperature increased with a time-delay of one hour, while the wind speed enhanced with very little time-delay. The values of the Joule heating rate during the peak of the substorm activity are as much as two orders of magnitude higher than the global average Joule heating rate estimated under disturbed conditions.