Publication Date:
2019-07-13
Description:
During small geomagnetic disturbances, ESRO 4 and OGO 6 gas analyzer measurements at high altitudes suggest that helium and atomic oxygen concentrations in the lower thermosphere decrease, whereas satellite drag measurements indicate that density increases. This discrepancy is explained by the corresponding temperature increases maximizing at high latitudes. ESRO 4 data suggest that at altitudes where atomic oxygen or helium predominates, the temperature increase compensates for the decrease in lower thermospheric concentrations. This yields a net density increase with geomagnetic disturbances. The Explorer 39 drag satellite measurements verify this conclusion. It is felt that the composition variations associated with minor disturbances indicate the upwelling of the polar atmosphere, circulation towards the equator, and subsidence in the equatorial region. ESRO measurements show that at low latitudes the increases in helium concentrations with geomagnetic disturbances are chiefly caused by the circulation from high latitudes and the subsidence at lower latitudes.
Keywords:
GEOPHYSICS
Type:
Symposium on Minor Constituents and Excited Species; Jun 09, 1976 - Jun 10, 1976|Symposium on Minor Constituents and Excited Species; Jun 08, 1976 - Jun 19, 1976; Philadelphia, PA; US
Format:
text
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