Is there a need to revise the aa index?

Clarke, Ellen; Clilverd, Mark ORCID: 2007 Is there a need to revise the aa index? [Poster] In: XXIV IUGG General Assembly 2007, Perugia, Italy, July 2007. (Unpublished)

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The three-hourly aa index, retrospectively calculated from 1868 [1], provides one of the longest continuous global geophysical data sets that can be used in the analysis of magnetospheric and ionospheric phenomena. Designed to cancel out systematic LT and annual variations, aa is derived according to: K indices from 2 geomagnetically near- antipodal magnetic observatories equivalent amplitudes (nT) and scale factors to correct for differences in geomagnetic latitude and local induction effects (providing aa and aa ) n s average of aa and aa n s Further LT cancellations can be gained by applying: 8-point (24 hour) running mean (aa*) [2]

Item Type: Publication - Conference Item (Poster)
Programmes: BGS Programmes > Seismology and Geomagnetism
NORA Subject Terms: Earth Sciences
Date made live: 01 Nov 2012 14:07 +0 (UTC)

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