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Indices - Ground Based - am

am IAGA-endorsed magnetic activity index

https://doi.org/10.25577/et43-6h78

2026-03-19 02:25:06Z

Index which purpose is to provide a characterization of global geomagnetic activity using a large set of stations representing all longitudes and possible hemispheric discrepancies.

ISGI website at EOST; am Citation : Mayaud, P.-N., Berthelier, A., Menvielle, M., & Chambodut, A. (2023). am geomagnetic index. EOST. (Dataset). https://doi.org/10.25577/et43-6h78 License: CC BY-NC https://creativecommons.org/licenses/by-nc/4.0/

Online

Open

CSV

Thank you for acknowledging the use of AMDA in publications with wording like "Data analysis was performed with the AMDA science analysis system provided by the Centre de Données de la Physique des Plasmas (CDPP) supported by CNRS, CNES, Observatoire de Paris and Université Paul Sabatier, Toulouse". See the Rules of the road at https://amda.cdpp.eu/help/policy.html . Please acknowledge the Data Providers.

Online

Open

CSV

VOTable

CDF

PNG

Thank you for acknowledging the use of AMDA in publications with wording like "Data analysis was performed with the AMDA science analysis system provided by the Centre de Données de la Physique des Plasmas (CDPP) supported by CNRS, CNES, Observatoire de Paris and Université Paul Sabatier, Toulouse". See the Rules of the road at https://amda.cdpp.eu/help/policy.html . Please acknowledge the Data Providers.

PT3H

am

am

am = (an + as)/2

nT

Am

Am

Daily Mean of am

nT