Auroral_Boundary_Geomag

Python scripts which were used to calculate auroral boundaries from geomagnetic data, as appears in Blake et al. (2020) Estimating Maximum Extent of Auroral Equatorward Boundary Using Historical and Simulated Surface Magnetic Field Data, JGR Space Physics, DOI: 10.1029/2020JA028284

There are two scripts:

1. EField_Calc.py calculates the E-field for a single INTERMAGNET site using the Quebec 1-D resistivity model.
2. Boundary_Calc.py calculates the extent of the auroral boundary using magnetic latitudes and maximum calculated Eh values from multiple INTERMAGNET sites.

Dependencies and Versions used

• gcvspline (0.4)
• numpy (1.18.4)
• matplotlib (3.1.1)
• math
• datetime (4.3)

Script Examples

EField_Calc.py Takes INTERMAGNET 60s B-Field data, and calculates E-Field data using a 1-D resistivity profile. This example is for 3 days of data from the Eskdalemuir site (found in the Sample_Data/ folder).

Boundary_Calc.py This script takes in magnetic latitudes and maximum E-field values found in the Sample_Data/ folder (2003_10_30.txt and 2009_10_07.txt). Natural cubic splines are fit to these data. The boundary is taken as the point on this fit that has the largest gradient:

And here are those boundaries for the non-log10 versions of the above plot:

Author

Written by Sean Blake in NASA GSFC, 2018-2020

Email: blakese@tcd.ie