2.2.6 spase://CDPP/NumericalData/AMDA/Indices/Ground_Based/ground-based-am am 2018-01-16T11:00:00Z The K scaled for each station, are averaged, and the result is converted into amplitude. The planetary index am is equal to (an + as) / 2.an is the hemispheric indice in North and as in South. ISGI website at EOST/UDS: http://isgi.unistra.fr; License: CC BY-NC https://creativecommons.org/licenses/by-nc/4.0/ spase://CDPP/Person/Aude.Chambodut DataProducer IAGA geomagnetic indices http://isgi.unistra.fr spase://CDPP/Repository/CDPP/AMDA Online Open AMDA at CDPP http://amda.cdpp.eu Text ISGI/UNISTRA spase://CDPP/Instrument/AMDA/Indices/Ground_Based MagneticField 1975-01-01T00:00:00Z 2018-01-13T21:00:00Z PT3H Earth.NearSurface am am am = (an + as)/2 nT Am Am Daily Mean of am nT