A new magnetic coordinate system for conjugate studies at high latitudes
書誌事項
- 公開日
- 1989-07
- 権利情報
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- http://onlinelibrary.wiley.com/termsAndConditions#vor
- DOI
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- 10.1029/ja094ia07p09139
- 公開者
- American Geophysical Union (AGU)
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説明
<jats:p>Studying magnetically conjugate phenomena at very high latitudes requires a magnetic coordinate system that is smooth and well defined at the geographic poles. In addition, it should provide for accurate comparisons at different altitudes. In this report we present a variation on the corrected geomagnetic coordinate system that is well defined and smooth over the entire globe. It provides an analytic expression relating geographic coordinates, including altitude, to the magnetic coordinates. The coordinate system is produced by tracing magnetic field lines using the IGRF85 reference magnetic field model with time derivatives updating the model to 1988. An expansion of the relationship in terms of spherical harmonics has been determined, which then provides the required well‐defined and smooth relationship over the entire globe. Independent expansions for different altitudes show a smooth functional relationship of the coefficients of the expansion with altitude, and therefore simple interpolation schemes can be used to provide an appropriate expansion at any altitude between 0 km and approximately 600 km. By reversing the process, the inverse expansions relating the magnetic coordinates to geographic coordinates have also been determined. The effects of the seasonal variation in the Sun's declination along with the variation in the Sun's apparent position due to the eccentricity of the Earth's orbit result in a variation of nearly 1 hour of magnetic local time for a fixed UT over the course of a year. In many applications this variation may be important and should be included when presenting data in terms of magnetic latitude and MLT.</jats:p>
収録刊行物
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- Journal of Geophysical Research: Space Physics
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Journal of Geophysical Research: Space Physics 94 (A7), 9139-9143, 1989-07
American Geophysical Union (AGU)
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詳細情報 詳細情報について
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- CRID
- 1361137044828311552
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- NII論文ID
- 30034731409
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- ISSN
- 01480227
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- データソース種別
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