Errors in direction finding of VLF waves caused by a sloping ionosphere
Article first published online: 7 DEC 2012
Copyright 2000 by the American Geophysical Union.
Volume 35, Issue 5, pages 1187–1192, September-October 2000
How to Cite
2000), Errors in direction finding of VLF waves caused by a sloping ionosphere, Radio Sci., 35(5), 1187–1192, doi:10.1029/1999RS002302.(
- Issue published online: 7 DEC 2012
- Article first published online: 7 DEC 2012
- Manuscript Accepted: 13 MAR 2000
- Manuscript Received: 8 DEC 1999
Lightning discharges emit very low frequency (VLF) radio waves commonly called “atmospherics.” In the past, lightning source locations were determined by the triangulation method from recordings at three widely separated stations in Japan. The three direction-of-arrival (DOA) lines, however, sometimes formed large triangles resulting in large uncertainties in source location. To approach this problem, the variational treatment is used here in which the sloping ionosphere plays an important role. By obtaining the time required to propagate from the source to the receiver via the Earth-ionosphere waveguide, it is found that the direction of propagation of a VLF wave can be bent along a parabolic curve. Using this concept of parabolic propagation, the locations of lightning discharges are compared with those determined by the triangular method.