AbstractWe discuss three new geomagnetic indices [the Inter-Hour Variability (IHV), the Inter-Diurnal Variability (IDV), Svalgaard, L., Cliver, E.W. The IDV index: its derivation and use in inferring long-term variations of the interplanetary magnetic field strength. J. Geophys. Res. 110, A12103. doi:10.1029/2005JA011203, 2005; and the Polar Cap Potential (PCP) index, Le Sager, P., Svalgaard, L. No increase of the interplanetary electric field since 1926. J. Geophys. Res. 109 (A7), A07106. doi:10.1029/2004JA010411, 2004], that are derivable from data available for a century or more. Each of these indices responds directly to either the solar wind magnetic field strength (B) or to different combinations of B and the solar wind speed (V). This over-determined system permits a reconstruction of these parameters for the past ∼150 years. The variation of yearly averages of B can be described as a constant value (4.6nT) plus a component varying with the square root of the sunspot number. Because the latter seems to exhibit a ∼100 year Gleissberg cycle, B does as well. Since 1890, annual averages of V range from a low of ∼300km/s in 1902 to 545km/s in 2003. The IHV-index fords a way to check the calibration of other long-term geomagnetic indices. We find that the ap-index tracks the variation of IHV, back to 1932 but that the aa-index (extended back to 1844) is systematically too low (3–6nT) before 1957, relative to modern values.


    Zugriff

    Zugriff prüfen

    Verfügbarkeit in meiner Bibliothek prüfen

    Bestellung bei Subito €


    Exportieren, teilen und zitieren



    Titel :

    Long-term geomagnetic indices and their use in inferring solar wind parameters in the past


    Beteiligte:
    Svalgaard, L. (Autor:in) / Cliver, E.W. (Autor:in)

    Erschienen in:

    Advances in Space Research ; 40 , 7 ; 1112-1120


    Erscheinungsdatum :

    2007-06-28


    Format / Umfang :

    9 pages




    Medientyp :

    Aufsatz (Zeitschrift)


    Format :

    Elektronische Ressource


    Sprache :

    Englisch






    Relationship between the Parameters of Various Solar Wind Types and Geomagnetic Activity Indices

    Dremukhina, L. A. / Lodkina, I. G. / Yermolaev, Yu. I. | Online Contents | 2018


    Relationship between the Parameters of Various Solar Wind Types and Geomagnetic Activity Indices

    Dremukhina, L. A. / Lodkina, I. G. / Yermolaev, Yu. I. | Springer Verlag | 2018


    Relation of magnetic field in the inner magnetosphere to geomagnetic indices and solar wind parameters

    Ostapenko, A. A. / Maltsev, Y. P. / Malkov, M. V. | British Library Online Contents | 1996