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Worldwide Hourly Values of Ionospheric Characteristics: foF2, M(3000)F2,
hF2,FoF1, M(3000)F1, hF, FoE, hE, foE2, hE2, foEs, fbEs, fmI, and FxI
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The ionosphere is that part of the Earth's atmosphere that results mainly
from the ionizing effect of Solar electromagnetic radiation. For poleware latitudes,
the ionizing effect of incident energetic particles is also significant. Traditionally,
the following ionospheric regions and their approximate height ranges have been designated:
D region (60-90 km); E region (90-150 km); F1 region (150-250 km); and F2 region (above
250 km). Ionosondes utilize the radio wave-reflecting properties
of the ionosphere. The product of the speed of light in a vacuum and half the elapsed
time between vertical transmission of a single frequency electromagnetic wave and
reception of the reflected wave at the transmitting location is defined as the virtual
height of that frequency. A sweep-frequency ionogram is a plot of virtual height versus
frequency and is recorded as nearly instantaneously as possible. These ionospheric
data consists mainly of hourly values for at least one to a maximum
of all of the following ionospheric characteristics (parameters). They are foF2, M(3000)F2,
hF2, foF1, M(3000)F1, hF, foE, hE, foE2, hE2, foEs, fbEs, hEs, fmI, and fxI. The values
are five byte (character) fields. The first three bytes of the field are reserved
for a numeric value; the last two bytes are reserved for the qualifying and descriptive
letter, if present. There are no decimals encoded in these data. Documentation is
supplied with each data order. Data are archived on CDROM, optical disk, and magnetic
tape. There are two CD-ROM's sold as a set. One contains 1957 - 1975 data; the other
contains 1976-1990 data. The CDROM contains ASCII files and runs on DOS-compatible
machines. A catalog, which lists the contents of the CDROM data set, is available
via anonymous FTP.ngdc.noaa.gov and GOPHER.ngdc.noaa.gov in the /STP/IONOSPHERE/CATALOG
directory. Additional data are available, but have not yet been
put on CDROM. Data are also available on magnetic tape and IBM compatible diskette.
U.S. Department of Commerce NOAA, NESDIS E/GC2 National Geophysical Data Center and
World Data Center - A 325 Broadway Boulder, CO 80303-3328 USA FAX:303-497-6513 Internet:info@mail.ngdc.noaa.gov
Phone:303-497-6414 Raymond O. Conkright
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