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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 (https://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 Lists
  • If the substorm onset list is central to your study please offer co-authorship to the authors of the technique you use.
  • When using substorm lists please include acknowledgements found here.
  • Include appropriate reference (see list below)
  • For details please see https://supermag.jhuapl.edu/substorms.
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 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 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 SME-LT, SMU-LT, SML-LT

Newell, P. T., and J. W. Gjerloev (2014), Local geomagnetic indices and the prediction of auroral power, J. Geophys. Res. Space Physics, 119, doi:10.1002/2014JA020524.

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

Forsyth, C., Rae, I. J., Coxon, J. C., Freeman, M. P., Jackman, C. M., Gjerloev, J., and Fazakerley, A. N. ( 2015), A new technique for determining Substorm Onsets and Phases from Indices of the Electrojet (SOPHIE), J. Geophys. Res. Space Physics, 120, 10,592– 10,606, doi:10.1002/2015JA021343.

Frey, H. U., Mende, S. B., Angelopoulos, V., and Donovan, E. F. (2004), Substorm onset observations by IMAGE‐FUV, J. Geophys. Res., 109, A10304, doi:10.1029/2004JA010607.

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

Liou, K. (2010),  Polar Ultraviolet Imager observation of auroral breakup, J. Geophys. Res.,  115, A12219, doi:10.1029/2010JA015578.

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.

Ohtani, S., and J. Gjerloev, Is the Substorm Current Wedge an Ensemble of Wedgelets?: Revisit to Midlatitude Positive Bays, accepted, J. Geophys. Res, 2020.

All existing substorm onset identification techniques have limitations. Please be aware of the caveats and assumptions of the technique you choose to use.

Technique

All three techniques utilizes the SML index which is the SuperMAG version of the AL index. This is provided at a 1-min resolution which is thus the temporal resolution of the substorm onset lists. In alphabetic order the technique used for each list is briefly explained below:

Forsyth et al., [2015] substorm list

The SOPHIE technique seeks to identify substorm expansion, recovery and potential growth phase (times outside the expansion and recovery phases) based on the time derivatives of filtered SML data. When these derivatives exceed a set percentile of the yearly distribution, the data is flagged as an expansion phase. Recovery phases are similarly identified, but the corresponding percentile is found iteratively such that the number of expansion and recovery phases is similar. Short phases, in particular between expansion and recovery phases, are reclassified and further processing is applied to account for the Gibbs effect when filtering the data. Finally, the rates of change of SML and SMU are compared and times when these are similar are flagged as potentially due to enhanced convection.  Note that this technique does not specify minimum or maximum phase lengths, nor that the phases occur in a specific order.

Frey et al., [2004 and 2006] substorm list

During the time period of 19 May 2000 (start of regular IMAGE-FUV operations) to 31 December 2002 we searched through the FUV data and determined substorm onsets. The prime data source were the WIC images because of their better spatial resolution. During times when WIC did not provide the best view of the aurora, SI-13 images were used instead. Substorms were identified if they fulfilled the following criteria: (1) a clear local brightening of the aurora has to occur, (2) the aurora has to expand to the poleward boundary of the auroral oval and spread azimuthally in local time for at least 20 min, (3) a substorm onset was only accepted as a separate event if at least 30 min had passed after the previous onset.

Liou [2010] substorm list

We first carefully examine a sequence of raw images from the UVI database. Once a substorm event, which consists of a sudden brightening of the aurora followed by a subsequent growing in the auroral intensity and region, is identified, the images are calibrated and reformatted in the AACGM coordinate system. Normally, we examine processed auroral images for a time interval of ∼10 min before and after a tentative onset (sudden brightening). A thorough inspection of the substorm process is performed to make sure that the onset is followed by a continuing poleward and zonal expansion of the substorm bulge (expansion phase). We do not require the poleward expansion to be over the poleward boundary of the oval, however. In general, a few degrees poleward expansion and 1–2 h magnetic local time widening are the minimal requirement. This is done by tracing substorm features back in time and finding the first brightening (auroral breakup) in the oval. Once the onset image is determined, we use the so‐called “region growing” image processing technique to determine bright pixels associated with the onset. The total observation accuracy is ∼1 degree in latitude.

Newell and Gjerloev [2011] substorm list

The SML data was considered at a 1-min cadence in a sliding 30 min buffer. An onset was identified at time=t0 when four conditions are satisfied:

  1. SML ( t0 + 1 ) − SML ( t0 ) < -15 nT
  2. SML ( t0 + 2 ) − SML ( t0 ) < -30 nT
  3. SML ( t0 + 3 ) − SML ( t0 ) < -45 nT
  4. 29 i=4  SML ( t0 + i ) _ 26  − SML ( t0 ) < -100 nT

Thus, the initial drop must be sharp (45 nT in 3 min), and sustained (must average 100 nT below the initial value for the remainder of the half hour). The SML onset is then placed at t0, the last minute before a 15 nT drop.

Ohtani and Gjerloev [2020] isolated substorm list

This technique is not meant to identify every substorm onset but rather to identify the onsets of isolated substorms with a high degree of confidence. Essentially onsets are identified using 6 criteria (see Figure 1). Each of these are based on classical substorm characteristics as published in the rich substorm literature.

Figure 1

References

Forsyth, C., Rae, I. J., Coxon, J. C., Freeman, M. P., Jackman, C. M., Gjerloev, J., and Fazakerley, A. N. ( 2015), A new technique for determining Substorm Onsets and Phases from Indices of the Electrojet (SOPHIE), J. Geophys. Res. Space Physics, 120, 10,592– 10,606, doi:10.1002/2015JA021343.

Frey, H. U., Mende, S. B., Angelopoulos, V., and Donovan, E. F. (2004), Substorm onset observations by IMAGE‐FUV, J. Geophys. Res., 109, A10304, doi:10.1029/2004JA010607.

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

Liou, K. (2010),  Polar Ultraviolet Imager observation of auroral breakup, J. Geophys. Res.,  115, A12219, doi:10.1029/2010JA015578.

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.

Ohtani, S., Gjerloev, J. W. (2020). Is the substorm current wedge an ensemble of wedgelets?: Revisit to midlatitude positive bays. Journal of Geophysical Research: Space Physics, 125, e2020JA027902.  doi:10.1029/2020JA027902

Substorm Onset Lists

All existing substorm onset identification techniques have limitations. Please be aware of the caveats and assumptions of the technique you choose to use.

Historically the AL index has been used to identify substorm events. Recently, several techniques are using the SuperMAG version of the AL index (SML) to identify substorm events.

SuperMAG includes the onsets identified by several different techniques. These lists are based on different techniques and assumptions and have somewhat different purpose. The user should understand these differences when using the lists.

Lists based on magnetic indices

  • Substorms: Newell and Gjerloev, 2011
  • Substorms: Forsyth et al., 2015
  • Isolated Substorms: Ohtani and Gjerloev, 2020

These lists are continuously updated as data are added or changed in the SuperMAG data holdings. Lists are continuous and cover more than 4 decades.

Lists based on auroral imaging

  • Substorms: Frey et al., 2004 & 2006
  • Substorms: Liou, 2010

These lists are derived from space-born imagers and cover years 2000-2005 and 1996-2007 respectively. Lists are final and have gaps in coverage as the imagers do not continuously monitor auroral latitudes. Auroral imaging is generally accepted as the most objective and robust technique to identify substorm onsets.


Time interval covered by the various techniques

Acknowledgement

If the substorm onset list is central to your study please offer co-authorship to the authors of the technique you use.

When using the Forsyth et al., [2015] substorm list: Please include the following acknowledgement: “We acknowledge the substorm timing list identified by the SOPHIE technique (Forsyth et al., 2015), the SMU and SML indices (Newell and Gjerloev, 2011); and the SuperMAG collaboration (Gjerloev et al. 2012).”

When using the Frey et al., [2004 and 2006] substorm list:  Please include the following acknowledgement: “We acknowledge the substorm timing list identified by Frey et al. [2004 and 2006]. This data is publicly available as auxiliary material to the named publications.”

When using the Liou [2010] substorm list:  Please include the following acknowledgement: “We acknowledge the substorm timing list identified by Liou [2010]. This data is publicly available as auxiliary material to the below listed publication.”

When using the Newell and Gjerloev [2011] substorm list: Please include the following acknowledgement: “We acknowledge the substorm timing list identified by the Newell and Gjerloev technique (Newell and Gjerloev, 2011), the SMU and SML indices (Newell and Gjerloev, 2011); and the SuperMAG collaboration (Gjerloev et al. 2012).”

When using the Ohtani and Gjerloev [2020] substorm list: Please include the following acknowledgement: “We acknowledge the substorm timing list identified by the Ohtani and Gjerloev technique (Ohtani and Gjerloev, 2020), the SMU and SML indices (Newell and Gjerloev, 2011); and the SuperMAG collaboration (Gjerloev et al. 2012).”

Caveats To Lists Derived From Magnetic Indices

  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 or the substorm timing which is derived from the indices. The user is encouraged to validate the data and derived products before using them in publications.
  2. Indices and thus the substorm list are revised as changes are made to the data holdings. Thus, the list is never final and included in the downloaded file is a date of creation which can be used as version control.
  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.

Caveats To Lists Derived From Spaceborne Imagers

  1. Spaceborne imagers do not provide continuous imaging of the auroral region. Thus, the lists will have gaps that are not due to a lack of auroral activity but merely the fact that there are no images of the auroral region.

References

Forsyth, C., Rae, I. J., Coxon, J. C., Freeman, M. P., Jackman, C. M., Gjerloev, J., and Fazakerley, A. N. ( 2015), A new technique for determining Substorm Onsets and Phases from Indices of the Electrojet (SOPHIE), J. Geophys. Res. Space Physics, 120, 10,592– 10,606, doi:10.1002/2015JA021343.

Frey, H. U., Mende, S. B., Angelopoulos, V., and Donovan, E. F. (2004), Substorm onset observations by IMAGE‐FUV, J. Geophys. Res., 109, A10304, doi:10.1029/2004JA010607.

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

Liou, K. (2010),  Polar Ultraviolet Imager observation of auroral breakup, J. Geophys. Res.,  115, A12219, doi:10.1029/2010JA015578.

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.

Ohtani, S., and J. Gjerloev, Is the Substorm Current Wedge an Ensemble of Wedgelets?: Revisit to Midlatitude Positive Bays, accepted, J. Geophys. Res, 2020.