On the computer generation of geomagnetic K-indices from digital data.

Hopgood, P.A.

doi:10.5636/jgg.38.861

Cited by 13 publications

(6 citation statements)

References 7 publications

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“…Many algorithms for the derivation of K indices from digital data have been proposed in recent years (Van Wijk & Nagtegaall977; Riddick &Stuart 1984;Hopgood 1986;Walker 1987;Wilson 1987;Jankowski et al 1988;Hattingh, Loubser & Nagtegaal 1989;Golovkov, Papitashvili & Papitashvili 1989;Pirjola, Ryno & Sucksdorff 1990). These algorithms have been tested with different data sets, and using different statistical tests.…”

Section: Introductionmentioning

confidence: 99%

Computer production of Kindices: review and comparison of methods

Menvielle

Papitashvili²,

Hakkinen

et al. 1995

Geophysical Journal International

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The K indices are to be hand-scaled from analogue magnetograms following morphological criteria expressed in the so-called Mayaud rules. All observatories used to follow these rules in the routine hand-scaling of K indices from analogue magnetograms. As a result of digitalization and automation of observatories, however, observers in charge who are experienced in K scaling from analogue magnetograms are becoming increasingly rare. Therefore the organizations running observatories were forced to find compensating machine methods for the production of K indices. The basic features of the K indices and the Mayaud rules are first reviewed, and then the methods developed for computer derivation of K indices are discussed.In order to decide which of the proposed algorithms was suitable, a comparison among them was organized by the IAGA Working Group on geomagnetic indices. The comparison was made with a common data set, using the same statistical tests. The results are summarized and discussed. Further comparisons between the K indices produced by computer with the different methods are presented in this paper. Four methods were acknowledged by the Working Group during the Vienna IUGG general Assembly in 1991. The results confirm that these methods provide acceptable results in comparison to the average quality of hand-scaled indices.A comparison between computer-produced K indices and reference K indices handscaled following the Bartels-Mayaud rules is also presented. It appears that only two acknowledged methods provide computer-produced K in good agreement with handscaled K. The best computer method (the FMI method) is found to be good enough to allow the continuation of the long tradition of producing K indices without any serious jump in the statistics.

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Section: Introductionmentioning

confidence: 99%

Computer production of Kindices: review and comparison of methods

Menvielle

Papitashvili²,

Hakkinen

et al. 1995

Geophysical Journal International

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“…Computer programs for calculating K index developed in the 1980s differ mainly in the method for the determination of the quiet daily variation Sq (Menvielle et al, 1995). Two main approaches are used: averaging the magnetograms of the nearest quiet days (Takahashi et al, 2001;Nechaev, 2006;Dmitriev and Filippov, 2010) and by smoothing the current magnetogram (Hopgood, 1986;Jankowski et al, 1988;Golovkov et al, 1989;Sucksdorff et al, 1991).…”

Section: Description Of K Indexmentioning

confidence: 99%

Historical <i>K</i> index data collection of Soviet magnetic observatories, 1957–1992

Sergeyeva

Гвишиани

Soloviev

et al. 2021

Earth Syst. Sci. Data

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Abstract. The K index is one of the oldest universal indices of geomagnetic activity, introduced in 1938 by Julius Bartels, that is still being widely used. Up to the present day, long-term time series of homogeneous K index records have been accumulated at data repositories all over the world. The multidecadal practice of its application makes it an indispensable source of information for the retrospective analysis of solar–terrestrial interaction for nearly eight solar cycles. Most significantly, while studying the historical geomagnetic data, K index data sheets are in certain cases far easier for automated analysis than the conventional analogue magnetograms. The presented collection includes the results of the K index determination at 41 geomagnetic observatories of the former USSR for the period from July 1957 to the early 1990s. This unique collection was formed at the World Data Center for Solar-Terrestrial Physics in Moscow. The historical data, which are offered to the international scientific community, cover the second half of the 20th century and can be used for the retrospective analysis and study of geomagnetic events in the past, as well as for data validation or forecasting (Sergeyeva et al., 2020). The dataset is available at: https://doi.org/10.1594/PANGAEA.922233, last access: 16 September 2020.

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“…Computer programs for calculating K index developed in the 1980s differ mainly in the method for determination of the quiet daily variation Sq (Menvielle et al, 1995). Two main approaches are used: averaging the magnetograms of the nearest quiet days (Takahashi et al, 2001;Nechaev, 2006;Dmitriev and Filippov, 2010) and by smoothing the current magnetogram (Hopgood, 1986;Jankowski et al, 1988;Golovkov et al, 1989;Sucksdorff et al, 1991).…”

Section: Description Of K Indexmentioning

confidence: 99%

Historical <i>K</i> index data collection of Soviet magnetic observatories, 1957–1992

Sergeyeva¹,

Гвишиани²,

Soloviev³

et al. 2020

Preprint

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Abstract. K index is one of the oldest universal indices of geomagnetic activity, introduced in 1938 by Julius Bartels, that is still being widely used. Up to the present day, long-term timeseries of homogeneous K index records have been accumulated at data repositories all over the world. The multidecadal practice of its application makes it an indispensable source of information for retrospective analysis of solar-terrestrial interaction for nearly eight Solar cycles. Most significantly, while studying the historical geomagnetic data, K index datasheets are in certain cases far easier for automated analysis than the conventional analogue magnetograms. The presented collection includes the results of the K index determination at 41 geomagnetic observatories of the former USSR for the period from July 1957 to early 1990s. This unique collection was formed at the World Data Center for Solar-Terrestrial Physics in Moscow. The historical data, which are offered to the international scientific community, cover the second half of the 20th century and can be used for retrospective analysis and study of geomagnetic events in the past as well as for data validation or forecasting (Sergeyeva et al., 2020). The dataset is available at: https://doi.org/10.1594/PANGAEA.922233, last access: 16 September 2020.

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On the computer generation of geomagnetic K-indices from digital data.

Cited by 13 publications

References 7 publications

Computer production of Kindices: review and comparison of methods

Computer production of Kindices: review and comparison of methods

Historical <i>K</i> index data collection of Soviet magnetic observatories, 1957–1992

Historical <i>K</i> index data collection of Soviet magnetic observatories, 1957–1992

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On the computer generation of geomagnetic K-indices from digital data.

Cited by 13 publications

References 7 publications

Computer production of Kindices: review and comparison of methods

Computer production of Kindices: review and comparison of methods

Historical &lt;i&gt;K&lt;/i&gt; index data collection of Soviet magnetic observatories, 1957–1992

Historical &lt;i&gt;K&lt;/i&gt; index data collection of Soviet magnetic observatories, 1957–1992

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Historical <i>K</i> index data collection of Soviet magnetic observatories, 1957–1992

Historical <i>K</i> index data collection of Soviet magnetic observatories, 1957–1992