Readme file for the aaa_special-purpose-datasets/spherical-elementary-and-equivalent-ionospheric-currents-weygand collection of data.

The Spherical Elementary Current (SEC) Amplitudes data set 
contains spherical elementary current amplitude data (J) 
derived using the SECS technique [Amm and Viljanen, 
Earth Planets Space, v. 51 pp. 431-440, 1999]. The location 
of these currents is in geographic coordinates at 10s 
resolution. The distribution of these currents is not the 
same as the equivalent ionospheric currents. The UT and 
date are obtained from the file name.

The SECS are the current amplitudes 
are a proxy for the field aligned current
and are derived for an altitude of 100 km above the surface
of the Earth. For more details see:
Weygand, J. M., O. Amm, A. Viljanen, V. Angelopoulos, 
D. Murr, M. J. Engebretson, H. Gleisner, and I. Mann 
(2011), Application and validation of the spherical 
elementary currents systems technique for deriving 
ionospheric equivalent currents with the North American 
and Greenland ground magnetometer arrays, J. Geophys. 
Res., 116, A03305
DOI: 10.1029/2010JA016177

The file format is SECSYYYYMMDD_HHMMSS.dat
The data are in 3 columns:
geographic latitude, 
geographic longitude, 
J (A, positive up and negative down).

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Quick look plots are under the Quicklook directory and also at
http://vmo.igpp.ucla.edu/data1/SECS/Quicklook/
In these plots display both the EICs and the SEC amplitudes.
The dot in the EIC panels show the location at which 
the current was determined. The length of the segment 
indicates the magnitude. See key in the lower right
corner. The direction of the current points AWAY
from the dot. The black line (if present) in the 
north-south direction indicates local geographic midnight.
The green line (if present) in the  north-south direction 
indicates local geographic noon.

--------------------------------------------------------------

The Equivalent Ionospheric Currents (EICs) data set 
contains horizontal ionospheric current data (Jx and 
Jy) derived using the SECS technique [Amm and Viljanen, 
Earth Planets Space, v. 51 pp. 431-440, 1999]. 
Positive Jx points to the geographic north pole. 
Positive Jy points to geographic east. The location 
of these currents is in geographic coordinates 
at 10s resolution. The distribution of these currents 
is not the same as the spherical elementary current 
amplitudes. The UT and date are obtained from the file name.

The equivalent ionospheric currents
are derived for an altitude of 100 km above the surface
of the Earth. For more details see:
Weygand, J. M., O. Amm, A. Viljanen, V. Angelopoulos, 
D. Murr, M. J. Engebretson, H. Gleisner, and I. Mann 
(2011), Application and validation of the spherical 
elementary currents systems technique for deriving 
ionospheric equivalent currents with the North American 
and Greenland ground magnetometer arrays, J. Geophys. 
Res., 116, A03305
DOI: 10.1029/2010JA016177

The EICS are the horizontal currents. 
The file format is EICSYYYYMMDD_HHMMSS.dat
The data are in 4 columns:
geographic latitude, 
geographic longitude, 
Jx (mA/m, which points to geographic north), 
Jy (mA/m, which points to geographic East)

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While these data are now fully public and citable, James M. 
Weygand (the author of this dataset) jweygand@igpp.ucla.edu 
is available to answer questions and is interested in 
participation in new  collaborative studies using this data.