Regular daily variations in satellite magnetic total intensity data
Regular magnetic daily quiet time (<i>Sq</i>) 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 <i>Sq</i> variat...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2007-11-01
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| Series: | Annales Geophysicae |
| Online Access: | https://www.ann-geophys.net/25/2167/2007/angeo-25-2167-2007.pdf |
| Summary: | Regular magnetic daily quiet time (<i>Sq</i>) 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 <i>Sq</i> variations in total intensity are therefore
calculated as an average over the 132 days for each hour of UT. Results are
compared with the <i>Sq</i> daily variations in total intensity for the region above
the ionosphere calculated from Malin's (1973) spherical harmonic analysis of
the <i>Sq</i> 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 <i>Sq</i> variations
in total intensity above the ionosphere. |
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| ISSN: | 0992-7689 1432-0576 |