High-resolution magnetic field modeling: application to MAGSAT and Ørsted data

Langlais, B.; Mandéa, Mioara; Ultré-Guérard, Pascale

doi:10.1016/s0031-9201(02)00207-8

Cited by 27 publications

(12 citation statements)

References 23 publications

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“…First, we pick up a model g j , γ j from the literature (Langlais et al, 2003;K [int] = 16, K [ext] = 2 ) and compute the values X , Y , Z of the model field at M points which are "real" points in the sense that there are points of the orbits of Champ where real measurements were made (specifically the data points corresponding to 130 days centered at 2003.0). We select N points P l from the whole set, the one closest to an optimal array of 1000 or 3000 points {Q l }, as explained in Fig.…”

Section: A Synthetic Examplementioning

confidence: 99%

Earth magnetic field modeling from Oersted and Champ data

2010

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We present a method to model geomagnetic field requiring only a restricted number of measurements on magnetic survey satellite orbits. These points are chosen in an optimal-or close to optimal-manner relying on recent developments in the problem of numerical integration over spheres. The method allows us to compute a series of models at short time intervals, namely 10 days in the present study. At each of these close dates several models are computed from independent sets of data; their redundancy in turn provides a control of results thanks to which the selection of data-for example, as a function of magnetic activity or latitude-may be reduced. We find that the internal low degree Gauss coefficients derived from Oersted and Champ data, respectively, differ from one another by 1 or 2 nT. We then take as a second example of the method application a brief study of the so-called external field. We compare the first-degree axisymmetric field with the D st index.

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Section: A Synthetic Examplementioning

confidence: 99%

Earth magnetic field modeling from Oersted and Champ data

2010

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“…significantly improved by using the recent satellite vector magnetic surveys carried out by the Ørsted, CHAMP and SAC-C missions. These missions permit the study of the geographical pattern of the secular variation during each satellite's lifetime, and also allow a comparison with former data from the MAGSAT mission in 1979 to 1980 (Langlais et al, 2003). Comparisons of MAGSAT and CHAMP satellite data indicate that the relative decrease of the geomagnetic field is particularly strong in the Atlantic and American sector (Figure 2).…”

Section: B 3c 3amentioning

confidence: 99%

The magnetic field changing over the southern African continent: a unique behaviour

Mandéa

Korte

Mozzoni

et al. 2007

South African Journal of Geology

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“…In addition, as the main field is large, a significant noise may result. For this reason, a degree 13 main field model at epoch 2000 computed by Langlais et al (2003) was substracted from the data. The result is denoted B=B−B model for the vector field, X, Y , Z for each component and F for the field intensity.…”

Section: Removing the Main Fieldmentioning

confidence: 99%

The field of the equatorial electrojet from CHAMP data

2006

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Abstract. We apply a simple linear transform, the alongtrack second derivative, to four years of scalar and vectorial data from the CHAMP satellite. This transform, reminiscent of techniques used in the interpretation of aeromagnetic surveys, is applied either to the geocentric spherical components of the field or to its intensity. After averaging in time and space, we first produce a map of the crustal field, then maps of the equatorial electrojet field at all local times and all universal times. The seasonal variation of the electrojet, its evolution with the solar cycle, and the effect of geomagnetic activity are discussed. The variation of the electrojet with longitude, an intriguing feature revealed by satellite data, is described in some detail, and it is shown that this longitude dependance is stable in time. The existence of a counterelectrojet in the morning, everywhere except over the Pacific Ocean, is established. The signatures of closure electric currents and of interhemispheric currents are also evidenced.

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High-resolution magnetic field modeling: application to MAGSAT and Ørsted data

Cited by 27 publications

References 23 publications

Earth magnetic field modeling from Oersted and Champ data

Earth magnetic field modeling from Oersted and Champ data

The magnetic field changing over the southern African continent: a unique behaviour

The field of the equatorial electrojet from CHAMP data

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