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Further examples of seasonal variations of ELF radio propagation parameters
Author(s) -
Bannister Peter R.
Publication year - 1999
Publication title -
radio science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.371
H-Index - 84
eISSN - 1944-799X
pISSN - 0048-6604
DOI - 10.1029/1998rs900003
Subject(s) - attenuation , ionosphere , reflection (computer programming) , environmental science , extremely low frequency , meteorology , atmospheric sciences , remote sensing , geodesy , physics , geology , electromagnetic field , optics , geophysics , quantum mechanics , computer science , programming language
In this paper we use experimentally determined values of effective attenuation rate, excitation factor, and relative phase velocity, along with the theoretical expressions derived by C. and P. Greifinger, to establish the seasonal variation of representative ionospheric conductivity parameters. These parameters include the reflection heights h 0 and h 1 (or h E ), inverse scale height β, and reference height H . The basis for this analysis is provided by the 1990–1992 76‐Hz field strength measurements taken at four land‐based ELF monitoring sites established by the U.S. Navy. The source for these measurements was the U.S. Navy's dual‐antenna transmitting system (WTF/MTF). The main conclusion of this paper is that the summertime and January nighttime attenuation rates are substantially lower than during other times of the year. This nighttime attenuation rate decrease appears to be mainly due to an increase in the inverse scale height β, rather than to an increase in the reflection heights h 0 and h E .