15 research outputs found
Ionospheric measurements during the CRISTA/MAHRSI campaign: their implications and comparison with previous campaigns
Ionospheric measurements during the CRISTA/MAHRSI campaign: their implications and comparison with previous campaigns
The CRISTA/MAHRSI experiment on board a space
shuttle was accompanied by a broad campaign of rocket, balloon and ground-based
measurements. Supporting lower ionospheric ground-based measurements were run in
Europe and Eastern Asia between 1 October-30 November, 1994. Results of
comparisons with long ionospheric data series together with short-term
comparisons inside the interval October-November, 1994, showed that the upper
middle atmosphere <br>
(<i>h</i> = 80-100 km) at middle latitudes of the Northern Hemisphere in the
interval of the CRISTA/MAHRSI experiment (4-12 November, 1994) was very close to
its expected climatological state. In other words, the average results of the
experiment can be used as climatological data, at least for the given
area/altitudes. The role of solar/geomagnetic and "meteorological"
control of the lower ionosphere is investigated and compared with the results of
MAP/WINE, MAC/SINE and DYANA campaigns. The effects of both solar/geomagnetic
and global meteorological factors on the lower ionosphere are found to be weak
during autumn 1994 compared to those in MAP/WINE and DYANA winters, and they are
even slightly weaker than those in MAP/SINE summer. The comparison of the four
campaigns suggests the following overall pattern: in winter the lower ionosphere
at northern middle latitudes appears to be fairly well
"meteorologically" controlled with a very weak solar influence. In
summer, solar influence is somewhat stronger and dominates the weak
"meteorological" influence, but the overall solar/meteorological
control is weaker than in winter. In autumn we find the weakest overall
solar/meteorological control, local effects evidently dominate.<br><br><b>Key words. </b>Ionosphere (ionosphere · atmosphere
interactions; mid-latitude ionosphere