Information Technology Reference
In-Depth Information
Fig. 19.8
Preservation information flow for scenario 2 - MST-complex
19.6 Ionosonde Data and the WDC Scenarios
The World Data Centre (WDC) system was created to archive and distribute data
collected from the observational programmes of the 1957-1958 International
Geophysical Year. Originally established in the United States, Europe, Russia,
and Japan, the WDC system has since expanded to other countries and to new sci-
entific disciplines. The WDC system now includes 52 Centres in 12 countries. Its
holdings include a wide range of solar, geophysical, environmental, and human
dimensions data. The WDC for Solar-Terrestrial Physics based at the Rutherford
Appleton laboratory holds ionospheric data comprising vertical soundings from
over 300 stations, mostly from 1957 onwards, though some stations have data
going back to the 1930s.
The Ionosonde is a basic tool for ionospheric research. Ionosondes are “Vertical
Incidence” radars which record the time of flight of a radio signal swept through
a range of frequencies (1-30 MHz) and reflected from the ionised layers of the
upper atmosphere (90-800 km) as an “ionogram”. These results are analysed
to give the variation of electron density with height up to the peak of the iono-
sphere. Such electron-density profiles provide most of the Information required
for studies of the ionosphere and its effect on radio communications. Only a
