Accessibility navigation


The development of a space climatology: 1. solar-wind magnetosphere coupling as a function of timescale and the effect of data gaps

Lockwood, M., Bentley, S. N., Owens, M. J., Barnard, L. A., Scott, C. J., Watt, C. E. and Allanson, O. (2019) The development of a space climatology: 1. solar-wind magnetosphere coupling as a function of timescale and the effect of data gaps. Space Weather, 17 (1). pp. 133-156. ISSN 1542-7390

[img] Text - Accepted Version
· Restricted to Repository staff only until 31 July 2019.

2MB
[img] Text - Supplemental Material
· Restricted to Repository staff only until 31 July 2019.

2MB

It is advisable to refer to the publisher's version if you intend to cite from this work. See Guidance on citing.

To link to this item DOI: 10.1029/2018SW001856

Abstract/Summary

Different terrestrial space weather indicators (such as geomagnetic indices, transpolar voltage, and ring current particle content) depend on different “coupling functions” (combinations of near-Earth solar wind parameters) and previous studies also reported a dependence on the averaging timescale, {\tau}. We study the relationships of the am and SME geomagnetic indices to the power input into the magnetosphere P_{\alpha}, estimated using the optimum coupling exponent {\alpha} for a range of {\tau} between 1 min and 1 year. The effect of missing data is investigated by introducing synthetic gaps into near-continuous data and the best method for dealing with them when deriving the coupling function, is formally defined. Using P_{\alpha}, we show that gaps in data recorded before 1995 have introduced considerable errors into coupling functions. From the near-continuous solar wind data for 1996-2016, we find {\alpha} = 0.44 plus/minus 0.02 and no significant evidence that {\alpha} depends on {\tau}, yielding P_{\alpha} = B^0.88 Vsw^1.90 (mswNsw)^0.23 sin4({\theta}/2), where B is the Interplanetary Magnetic Field (IMF), Nsw the solar wind number density, msw its mean ion mass, Vsw its velocity and {\theta} is the IMF clock angle in the Geocentric Solar Magnetospheric reference frame. Values of P_{\alpha} that are accurate to within plus/minus 5% for 1996-2016 have an availability of 83.8% and the correlation between P_{\alpha} and am for these data is shown to be 0.990 (between 0.972 and 0.997 at the 2{\sigma} uncertainty level), 0.897 plus/minus 0.004, and 0.790 plus/minus 0.03, for {\tau} of 1 year, 1 day and 3 hours, respectively, and that between P_{alpha} and SME at {\tau} of 1 min. is 0.7046 plus/minus 0.0004.

Item Type:Article
Refereed:Yes
Divisions:Faculty of Science > School of Mathematical, Physical and Computational Sciences > Department of Meteorology
ID Code:78209
Publisher:American Geophysical Union

University Staff: Request a correction | Centaur Editors: Update this record

Page navigation