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The Lunar Tide in ƒ b E s
Author(s) -
Tarpley J. D.,
Matsushita S.
Publication year - 1971
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/rs006i002p00191
Subject(s) - blanketing , amplitude , geology , new moon , oscillation (cell signaling) , physics , variation (astronomy) , geodesy , lunar soil , geophysics , atmospheric sciences , astrophysics , astronomy , optics , stars , biology , genetics
Hourly measurements of the blanketing frequency of sporadic E (ƒ b E s ) made during the years 1958 through 1965 have been analyzed for lunar daily variations. The data, which came from ten stations, were analyzed by the Chapman‐Miller method. Both seasonal and yearly average lunar variations were obtained. The lunar semidiurnal oscillations in ƒ b E s ranged from 0.01 to 0.04 MHz, with maximums occurring from 7 to 9 hours lunar time. The amplitude of the lunar tide in ƒ b E s is an order of magnitude less than the lunar variations of ƒ 0 E s . Since ƒ b E s is close to the plasma frequency of E s , the oscillation in ƒ b E s represents a lunar variation in the electron density of E s layers, whereas the significance of the lunar variation of ƒ 0 E s is not clear. The phases of the lunar tides in ƒ b E s , ƒ 0 E s , and h ′ E s are found to be nearly the same. Two sources of lunar influence on E s electron density are considered (1) wind shears in the lunar tide acting to augment or decrease the wind shears responsible for E 8 , and (2) interaction of E 8 with electrostatic fields associated with the lunar current system.