Study of Equatorial Clutter Using Observed and Simulated Long Range Backscatter Ionograms.
Abstract
This synoptic study of equatorial clutter used over 6200 long range (8000 nmi) backscatter ionograms from the East Coast Radar System at Bangor, ME, obtained from 1100 to 0600 Local Time during the 22 month period from October 1991 to July 1993 Data were collected in five 7.5 deg width azimuthal sectors (radar beams 1-6, 1-8, 2-4, 2-8 and 3-5) from 58 to 170 deg. T. The backscatter clutter signatures can be identified with an equatorial clutter region covering a dip latitude range of +/- 40 deg. Equatorial clutter typically begins after sunset and continues through midnight, with a minimum of activity between 1700 and 2200 LT. The clutter range shows some dependence on solar activity with a reduction in range from the radar during low solar activity periods. These data did not show any dependence of clutter on operating frequency or on magnetic activity. Synthetic backscatter ionograms were generated using the Parameterized Ionospheric Model developed by Anderson at Phillips Laboratory, with the raytrace technique of Jones and Stephenson. The analysis shows that the equatorial dome of the ionosphere favors the chordal mode of reflection from the south side of the dome, which produces horizontal traces as clutter signatures on the backscatter ionograms. The reduction in range at low solar activity is associated with the lowering of the mean height of the ionospheric dome. In beams 2-8 and 3-5 the ionospheric dome structure is associated with the equatorial (Appleton) anomaly. This dome structure geometry favors the chordal mode of reflection.
Document Details
- Document Type
- Technical Report
- Publication Date
- Aug 29, 1995
- Accession Number
- ADA309841
Entities
People
- B. S. Dandekar
Organizations
- Phillips Laboratory