Magnetic Indices

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Rules of the Road

SuperMAG is made possible by the generous contribution of data by numerous collaborators. To ensure their continued operation the user must follow the below rules-of-the-road. Data, plots or derived data products are provided under the limitations of "fair use" and cannot be redistributed. Contact the individual instrument PI and the SuperMAG PI for requests that are in conflict with these restrictions.

The user is requested to acknowledge individual collaborators and SuperMAG when original data, derived data, movies, or data products are used in publications and/or presentations.

When Using Data

In all cases:

  • Include acknowledgement as listed on the SuperMAG website.
  • Include references to a technical papers for stations used (see list below).
  • Include SuperMAG reference: Gjerloev, J. W. (2012), The SuperMAG data processing technique, J. Geophys. Res., 117, A09213, doi:10.1029/2012JA017683.

In cases that only a few stations play a key role and their data are central to the scientific conclusion of the paper:

  • Offer of co-authorship to the PI (or PIs) of those stations and reference the appropriate paper (see list below).
When Using Indices
  • Include the text: “We gratefully acknowledge the SuperMAG collaborators (http://supermag.jhuapl.edu/info/?page=acknowledgement)”
  • Include appropriate reference for indices used (see list below).
  • Include SuperMAG reference: Gjerloev, J. W. (2012), The SuperMAG data processing technique, J. Geophys. Res., 117, A09213, doi:10.1029/2012JA017683.
When Using Substorm List
  • Include the text: “We gratefully acknowledge the SuperMAG collaborators (http://supermag.jhuapl.edu/info/?page=acknowledgement)”
  • Include appropriate reference for Substorm List (see list below).
  • Include SuperMAG reference: Gjerloev, J. W. (2012), The SuperMAG data processing technique, J. Geophys. Res., 117, A09213, doi:10.1029/2012JA017683.
When Using OMNI When Using Imaging When using INTERMAGNET Data

References

Collaborator EMMA

Lichtenberger J., M. Clilverd, B. Heilig, M. Vellante, J. Manninen, C. Rodger, A. Collier, A. Jørgensen, J. Reda, R. Holzworth, and R. Friedel (2013), The plasmasphere during a space weather event: first results from the PLASMON project, J. Space Weather Space Clim., 3, A23 (www.swsc-journal.org/articles/swsc/pdf/2013/01/swsc120062.pdf).

Collaborator IMAGE Chain

Tanskanen, E.I. (2009), A comprehensive high-throughput analysis of substorms observed by IMAGE magnetometer network: Years 1993-2003 examined, 114, A05204, doi:10.1029/2008JA013682.

Collaborator MACCS

Engebretson, M. J., W. J. Hughes, J. L. Alford, E. Zesta, L. J. Cahill, Jr., R. L. Arnoldy, and G. D. Reeves (1995), Magnetometer array for cusp and cleft studies observations of the spatial extent of broadband ULF magnetic pulsations at cusp/cleft latitudes , J. Geophys. Res., 100, 19371-19386, doi:10.1029/95JA00768.

Collaborator McMAC Chain

Chi, P. J., M. J. Engebretson, M. B. Moldwin, C. T. Russell, I. R. Mann, M. R. Hairston, M. Reno, J. Goldstein, L. I. Winkler, J. L. Cruz-Abeyro, D.-H. Lee, K.Yumoto, R. Dalrymple, B. Chen, and J. P. Gibson (2013), Sounding of the plasmasphere by Mid-continent MAgnetoseismic Chain magnetometers, J. Geophys. Res. Space Physics, 118, doi:10.1002/jgra.50274.

Collaborator MAGDAS / 210 Chain

Yumoto, K,. and the CPMN Group (2001), Characteristics of Pi 2 magnetic pulsations observed at the CPMN stations: A review of the STEP results, Earth Planets Space, 53, 981-992.

Collaborator CARISMA

Mann, I. R., et al. (2008), The upgraded CARISMA magnetometer array in the THEMIS era, Space Sci. Rev., 141, 413–451, doi:10.1007/s11214-008-9457-6.

Collaborator AALPIP

Clauer, C. R., et al. (2014), An autonomous adaptive low-power instrument platform (AAL-PIP) for remote high-latitude geospace data collection, Geosci. Instrum. Methods Data Syst., 3, 211–227, doi:10.5194/gi-3-211-2014

Collaborator INTERMAGNET

Love, J. J., Chulliat, A., (2013), An international network of magnetic observatories, Eos, 94(42), 373-374, doi:10.1002/2013EO420001

SuperMAG

Gjerloev, J. W. (2012), The SuperMAG data processing technique, J. Geophys. Res., 117 , A09213, doi:10.1029/2012JA017683.

Indices SMLs, SMLd, SMUs, SMUd

Gjerloev, J. W., R. A. Hoffman, S. Ohtani, J. Weygand, and R. Barnes, Response of the Auroral Electrojet Indices to Abrupt Southward IMF Turnings (2010), Annales Geophysicae, 28, 1167-1182.

Indices SML, SMU, SME

Newell, P. T., and J. W. Gjerloev (2011), Evaluation of SuperMAG auroral electrojet indices as indicators of substorms and auroral power, J. Geophys. Res., 116, A12211, doi:10.1029/2011JA016779.

Indices SMR, SMR-LT

Newell, P. T. and J. W. Gjerloev (2012), SuperMAG-Based Partial Ring Current Indices, J. Geophys. Res., 117, doi:10.1029/2012JA017586.

Substorm List

Newell, P. T., and J. W. Gjerloev (2011), Evaluation of SuperMAG auroral electrojet indices as indicators of substorms and auroral power, J. Geophys. Res., 116, A12211, doi:10.1029/2011JA016779.

Newell, P. T., and J. W. Gjerloev (2011), Substorm and magnetosphere characteristic scales inferred from the SuperMAG auroral electrojet indices, J. Geophys. Res., 116, A12232, doi:10.1029/2011JA016936.

Magnetic Indices

Magnetic indices are derived from the magnetometer data provided by the SuperMAG collaborators. These indices are not official indices and are not authorized by IAGA. The official indices can be found at World Data Center for Geomagnetism, Kyoto

If you use the indices in publications and/or presentations please clearly indicate that these are SuperMAG derived indices.

Caveats

  1. Despite comprehensive and time consuming data correction and validation SuperMAG does not guarantee the quality of the data from the individual station and thus does not guarantee the quality of the indices either. The user is encouraged to validate the data before using them in publications.
  2. Indices are revised as new stations are added to the data holdings.
  3. Finally, the indices are based on the SuperMAG version of the data and thus have undergone error correction, temporal resampling, rotation, and the baseline has been subtracted. The data used are thus not equivalent to the original data that can be obtained from the collaborators.

Method of derivation: SMU and SML indices (based on AU and AL indices)

  1. Based on all available ground magnetometer stations at geomagnetic latitudes between +40º and +80º degrees;
  2. From all available stations we use the N component with the baseline removed;
  3. SMU is defined as the maximum value at each moment of the N component;
  4. SML is defined as the minimum value at each moment of the N component.
  5. SME = SMU - SML

Typically, these indices are derived from approximately 110 stations. For full description see Newell and Gjerloev [2011a,b].

The sunlit and darkness indices are derived in the same way. The difference is that the darkness indices (SMUD and SMLD) are derived from stations located under the dark ionosphere. Likewise, the sunlit indices (SMUS and SMLS) are derived from stations located under the sunlit ionosphere. The terminator is defined at an altitude of 200 km for solar zenith angles of 104°. In agreement with the above definition (5) we finally get:

  1. SMES = SMUS - SMLS
    SMED = SMUD - SMLD

For full description see Gjerloev et al. [2009].

Method of derivation: SMR indices (SMR based on SYMH)

  1. Based on all available ground magnetometer stations at geomagnetic latitudes (mlat) between -50 and +50 degrees;
  2. From all available stations we use the N component with the baseline removed;
  3. The magnetic latitude is used for a correction: Ncorr=N/cos(mlat);
  4. Four equally sized local time sectors are defined with centers at 00, 06, 12, 18 MLT;
  5. SMR-00 is defined as the average at each moment of Ncorr for all available stations within the local time sector (21 MLT to 03 MLT). Likewise for the other sectors;
  6. SMR is defined as: SMR = (SMR-00 + SMR-06 + SMR-12 + SMR-18)/4

Typically, the SMR is derived from approximately 100 stations. For full description see Newell and Gjerloev [2012].

References

Davis, T. N., and M. Sugiura (1966), Auroral electrojet activity index AE and its universal time variations, J.Geophys.Res., 71, 785, doi:10.1029/JZ071i003p00785.

Gjerloev, J. W. (2009), A Global Ground-Based Magnetometer Initiative, EOS, 90, 230-231, doi:10.1029/2009EO270002.

Gjerloev, J. W., R. A. Hoffman, S. Ohtani, J. Weygand, and R. Barnes, Response of the Auroral Electrojet Indices to Abrupt Southward IMF Turnings (2010), Annales Geophysicae, 28, 1167-1182. (www.ann-geophys.net/28/1167/2010/angeo-28-1167-2010.pdf)

Gjerloev, J. W. (2012), The SuperMAG data processing technique, J. Geophys. Res., 117, doi:10.1029/2012JA017683.

Newell, P. T., and J. W. Gjerloev (2011), Evaluation of SuperMAG auroral electrojet indices as indicators of substorms and auroral power, J. Geophys. Res., 116, A12211, doi:10.1029/2011JA016779.

Newell, P. T., and J. W. Gjerloev (2011), Substorm and magnetosphere characteristic scales inferred from the SuperMAG auroral electrojet indices, J. Geophys. Res., 116, A12232, doi:10.1029/2011JA016936.

Newell, P. T. and J. W. Gjerloev (2012), SuperMAG-Based Partial Ring Current Indices, J. Geophys. Res., 117, doi:10.1029/2012JA017586.

Sugiura, M. (1964), Hourly values of equatorial Dst for the IGY, Ann. Int. Geophys., 35, 9, Pergamon Press, Oxford.

Magnetic indices are derived from the magnetometer data provided by the SuperMAG collaborators. These indices are not official indices and are not authorized by IAGA. The official indices can be found at World Data Center for Geomagnetism, Kyoto.

If you use the indices in publications and/or presentations please clearly indicate that these are SuperMAG derived indices and are not the official indices.

Available indices

SMU
Maximum eastward auroral electrojets strength.
Upper envelope of N-component for stations between 40° and 80° magnetic north.
SML
Maximum westward auroral electrojets strength.
Lower envelope of N-component for stations between 40° and 80° magnetic north.
SME
SMU-SML
SMR
Symmetric ring current index.
SMR-LT
Partial ring current indices, SMR-00, SMR-06, SMR-12, SMR-18.
Ring current indices partitioned by MLT (Magnetic local time).

Magnetic longitude and latitude of the stations are given in AACGM coordinates.

Full description

Solar Wind Data

Solar Wind data is generously provided by OMNI, Dr. Natalia Papitashvili. SuperMAG uses the 1-min-averaged, field/plasma data sets shifted to the Earth's bow shock nose.

Full description