The O1 Component of the Geomagnetic Lunar Daily Variation

Tarpley, J. Dan

doi:10.5636/jgg.23.169

Cited by 18 publications

(22 citation statements)

References 9 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…As discussed below, lunar variations in the neutral atmosphere can lead to changes in ionospheric parameters such as electron density and electric and magnetic fields. The most important lunar variation occurs at the lunar semidiurnal ( M 2 ) period of 12.42 hr, although some brief mention has been made in the literature of the quasi‐diurnal lunar component (O 1 , period = 25.82 hr) on the basis of ionospheric and geomagnetic observations (Chapman, ; Fejer & Tracy, ; Jones & Jones, ; Pedatella & Forbes, ; Tarpley, ; Winch, ). The diurnal lunar tide is introduced by the inclination of the Moon's orbit with respect to Earth's equatorial plane.…”

Section: Introductionmentioning

confidence: 99%

Lunar Tide in the F Region Ionosphere

Forbes

Zhang

2019

JGR Space Physics

View full text Add to dashboard Cite

In this paper the magnetic latitude (±50°) and longitude, local solar time (LST), and month‐to‐month variability of the M2 lunar semidiurnal tide in the ionosphere is revealed through analysis of topside F region electron density measurements by the Planar Langmuir Probe instrument on the CHAMP satellite during the two 5‐year periods 2001–2005 and 2005–2009. The local time precession rate of CHAMP is such that 5 years is required to obtain full LST coverage for every month of the year at each latitude of interest. Thus, each 5‐year period is compressed into one equivalent year. M2 amplitudes, expressed in terms of percent residuals from a background value, range between about 3% and 20% and vary considerably with LST and magnetic longitude. Longitude variations in principle arise from zonal asymmetries in lunar tidal forcing due to Earth and ocean tides, as well as magnitude of Earth's magnetic field. The O1 diurnal tide is also discussed in the context of CHAMP and other measurements of the F region ionosphere.

show abstract

Section: Introductionmentioning

confidence: 99%

Lunar Tide in the F Region Ionosphere

Forbes

Zhang

2019

JGR Space Physics

View full text Add to dashboard Cite

show abstract

“…Pedatella and Forbes [] observed the diurnal lunar tide as well; however, there are few studies about this oscillation in the ionosphere and the mechanism of generation is poorly understood. For instance, Tarpley [] pointed out the ocean tide as a likely source for the diurnal lunar tide in the atmosphere.…”

Section: Resultsmentioning

confidence: 99%

Lunar tides in total electron content over Brazil

et al. 2017

View full text Add to dashboard Cite

Using data from Global Navigation Satellite Systems dual frequency receivers, the lunar tides were studied in the ionospheric total electron content (TEC) over Brazil from 2011 to 2014. In order to calculate the amplitudes and phases of the lunar tides, quiet magnetic days within a 27 day (window) have been used to remove the solar rotation effects. Relative residuals TEC were calculated by performing a spectral analysis by removing the solar tide contributions. Lastly, a lunar month size window was used to calculate the amplitude and phase of the lunar components. Lunar diurnal tide amplitudes showed a semiannual variation with maximum in the equinox months for almost all latitudes, while lunar semidiurnal amplitudes were larger in December and January and may be related to sudden stratospheric warming events. Both components did not display significant longitudinal variation what could be due to the short range of longitude (30°). Lunar diurnal amplitudes were basically uniform over Brazil, while lunar semidiurnal amplitudes showed some peaks over the equatorial ionization anomaly crest and minimum values near the magnetic equator.

show abstract

“…The results of WINCH (1970WINCH ( , 1971, TARPLEY (1971), RAO and SASTRI (1974) and SASTRI et al (1975) have indicated that O1 tide is able to produce detectable variations in the geomagnetic field. The time dependence of L(O1), which is determined by the product of the terms representing lunar diurnal atmospheric tidal movement and the time variation of electrical conductivity of the ionosphere, restricted to the first two harmonics, is given by: 3 L(O1)-csin(nt-2-h+2) vn ( 1) where c,, is the amplitude of the nth harmonic, t is mean solar time increasing *Forms part of the author's Ph .…”

Section: Introductionmentioning

confidence: 92%

“…It is likely that each such transient variation might contribute to the numerical estimate of the other. In fact, the results of WINCH (1970) andTARPLEY (1971) indicated the presence of such contamination. WINCH (1970) suggested that appropriate adjustments made for the effect of L(O1), may substantially reduce the seasonal variation of L(M2) and may, thus, offer an explanation for the unduly large seasonal variation observed in global L(M2).…”

Section: Introductionmentioning

confidence: 93%

O1 component of geomagnetic lunar daily variation at alibag and its contamination by M2 component.

Arora

1979

J. geomagn. geoelec

View full text Add to dashboard Cite

An analysis of absolute mean hourly values of the three geomagnetic elements H, D and Z at Alibag for the period 1932-1972 has revealed clear and significant L(O1), the geomagnetic lunar daily variation associated with the lunar atmospheric tide 01. Partial tides are small in comparison with the phase law tides, suggesting that the variation resulting from the atmospheric tide O1 and higher harmonics of ionospheric conductivity contribute little to L(O1) at Alibag. Separation of L(O1) into parts of oceanic and ionospheric origin shows that (i) primary source of L(O1) in Z is the oceanic dynamo; (ii) smaller amplitude of the first harmonic of L(O1) compared to that of the second, contrary to expectation, is not due to the influence of oceanic dynamo contribution on L(O1). It is inferred that even yearly L(O1) contains some contribution from L(M2), lunar variation associated with the atmospheric tide M2. Next, by applying the formulae due to Winch, the seasonal harmonics of L(O1) and L(M2) are corrected for the possible contamination of one by the other. It is found that seasonal progression of L(O1) and L(M2) prior to and after the removal of the effect of one from the other remains the same.

show abstract

The O1 Component of the Geomagnetic Lunar Daily Variation

Cited by 18 publications

References 9 publications

Lunar Tide in the F Region Ionosphere

Lunar Tide in the F Region Ionosphere

Lunar tides in total electron content over Brazil

O1 component of geomagnetic lunar daily variation at alibag and its contamination by M2 component.

Contact Info

Product

Resources

About