Spherical Harmonic Analysis of Geomagnetic Tides, 1964-1965

Winch, D. E.

doi:10.1098/rsta.1981.0193

Cited by 101 publications

(54 citation statements)

References 4 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…(1) from models for Sq and the main field at the same epoch. The analyses of Malin (1973) for the IGY years of relatively high sunspot number and of Winch (1981) for the IQSY years of relatively low sunspot number are the only analyses available for comparison with the CHAMP results, and both were for epochs well before that of CHAMP.…”

Section: B Sq At Satellite Altitude From Observatory Datamentioning

confidence: 99%

“…The average sunspot number was 187 for the interval from 1 July 1957 to 31 December 1959 over which Malin (1973) analysed IGY data and for the IQSY years 1964 and 1965, the sunspot number was much smaller, at 15. For this reason, the Malin (1973) Sq variation coefficients for the IGY were considered more suitable for the present purpose of comparison than those of Winch (1981) for the IQSY years. For the main field in Eq.…”

Section: B Sq At Satellite Altitude From Observatory Datamentioning

confidence: 99%

“…Malin (1973) analysed solar and lunar magnetic variations for the IGY years. Winch (1981) analysed solar, lunar and lunar-elliptic tides and their seasonal change for the International Quiet Sun Years (IQSY) of 1964 and 1965.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Regular daily variations in satellite magnetic total intensity data

et al. 2007

Self Cite

View full text Add to dashboard Cite

Abstract. Regular magnetic daily quiet time (Sq) variations in total intensity of about 30 nT amplitude are determined in Universal Time (UT) from satellite magnetic field measurements. The CHAMP satellite traverses all hours of local time in 132 days and the Sq variations in total intensity are therefore calculated as an average over the 132 days for each hour of UT. Results are compared with the Sq daily variations in total intensity for the region above the ionosphere calculated from Malin's (1973) spherical harmonic analysis of the Sq Fourier coefficients for hourly mean value magnetic data from a global distribution of ground-based magnetic observatories. From the reasonable agreement between the two calculations, we conclude that low-Earth orbit satellites that traverse all hours of local time can determine Sq variations in total intensity above the ionosphere.

show abstract

Section: B Sq At Satellite Altitude From Observatory Datamentioning

confidence: 99%

Section: B Sq At Satellite Altitude From Observatory Datamentioning

confidence: 99%

See 1 more Smart Citation

Regular daily variations in satellite magnetic total intensity data

et al. 2007

Self Cite

View full text Add to dashboard Cite

show abstract

“…Some discrepancies are expected from the different data sets and techniques used. Pedatella et al (2011) used the CHAMP vector magnetometer observations during , while Stening and Winch (2013 used magnetic data from 130 ground stations during 1964-1965, originally analyzed by Winch (1981). For the baseline of Sq, Pedatella et al (2011) used the POMME6.1 geomagnetic field model , while Stening and Winch (2013) used the daily mean value.…”

Section: Sqmentioning

confidence: 99%

“…The analysis of L is usually made with the data covering several months or longer. When the global L field is determined, it is possible to apply the spherical harmonic analysis so as to separate the external and internal sources (e.g., Matsushita and Maeda 1965b;Malin 1973;Winch 1981;Matsushita and Xu 1984;Yamazaki 2014;Çelik 2014). Figure 5 shows the external L current systems presented by Çelik (2014).…”

Section: Determination Of Lmentioning

confidence: 99%

Sq and EEJ—A Review on the Daily Variation of the Geomagnetic Field Caused by Ionospheric Dynamo Currents

2016

View full text Add to dashboard Cite

A record of the geomagnetic field on the ground sometimes shows smooth daily variations on the order of a few tens of nano teslas. These daily variations, commonly known as Sq, are caused by electric currents of several μA/m 2 flowing on the sunlit side of the Eregion ionosphere at about 90-150 km heights. We review advances in our understanding of the geomagnetic daily variation and its source ionospheric currents during the past 75 years. Observations and existing theories are first outlined as background knowledge for the nonspecialist. Data analysis methods, such as spherical harmonic analysis, are then described in detail. Various aspects of the geomagnetic daily variation are discussed and interpreted using these results. Finally, remaining issues are highlighted to provide possible directions for future work.

show abstract

Ionospheric disturbance dynamo associated to a coronal hole: Case study of 5–10 April 2010

et al. 2014

View full text Add to dashboard Cite

In this paper we study the planetary magnetic disturbance during the magnetic storm occurring on 5 April 2010 associated with high-speed solar wind stream due to a coronal hole following a coronal mass ejection. We separate the magnetic disturbance associated to the ionospheric disturbance dynamo (Ddyn) from the magnetic disturbance associated to the prompt penetration of magnetospheric electric field (DP2). This event exhibits different responses of ionospheric disturbance dynamo in the different longitude sectors (European-African, Asian, and American). The strongest effect is observed in the European-African sector. The Ddyn disturbance reduces the amplitude of the daytime H component at low latitudes during four consecutive days in agreement with the Blanc and Richmond's model of ionospheric disturbance dynamo. The amplitude of Ddyn decreased with time during the 4 days. We discuss its diverse worldwide effects. The observed signature of magnetic disturbance process in specific longitude sector is strongly dependent on which Earth's side faces the magnetic storms (i.e., there is a different response depending on which longitude sector is at noon when the SSC hits). Finally, we determined an average period of 22 h for Ddyn using wavelet analysis.

show abstract

Spherical Harmonic Analysis of Geomagnetic Tides, 1964-1965

Abstract: D. E. W INCHhigh latitude observatories to include only those results that varied with local time. He pre sented the first results of separation of the magnetic tidal fields into internal and external parts. His analysis of the solar magnetic tide determined the following local time terms:

Cited by 101 publications

References 4 publications

Regular daily variations in satellite magnetic total intensity data

Regular daily variations in satellite magnetic total intensity data

Sq and EEJ—A Review on the Daily Variation of the Geomagnetic Field Caused by Ionospheric Dynamo Currents

Ionospheric disturbance dynamo associated to a coronal hole: Case study of 5–10 April 2010

Contact Info

Product

Resources

About