OCB Boundary Correction

Many high-latitude boundaries are related to each other. Both the poleward edge of the auroral oval and the R1/R2 current boundary have been successfully related to the OCB. If you have a data set of boundaries that can be related to the OCB, OCBpy is capable of applying this correction as a function of MLT. These corrections are applied using the rfunc and rfunc_kwargs keyword arguments in ocbpy.OCBoundary object. Several correction functions are provided as a part of ocbpy.ocb_correction module.

OCB Correction

Functions that specify the boundary location as a function of MLT

Functions

circular(mlt, [r_add])
Return a circular boundary correction for a specified offset
elliptical(mlt, [instrument, method])
Return the ellptical boundary correction for a data set and method
harmonic(mlt, [instrument, method])
Return the harmonic boundary correction for a data set and method

References

Burrell, A. G. et al.: AMPERE Polar Cap Boundaries, Ann. Geophys., 38, 481-490, doi:10.5194/angeo-38-481-2020, 2020.

ocbpy.ocb_correction.circular(mlt, r_add=0.0)[source]

Return a circular boundary correction

Parameters:
mlt : (float or array-like)

Magnetic local time in hours (not actually used)

r_add : (float)

Offset added to default radius in degrees. Positive values shift the boundary equatorward, whilst negative values shift the boundary poleward. (default=0.0)

Returns:
r_corr : (float or array-like)

Radius correction in degrees at this MLT

ocbpy.ocb_correction.elliptical(mlt, instrument='ampere', method='median')[source]

Return the results of an elliptical correction to the data boundary

Parameters:
mlt : (float or array-like)

Magnetic local time in hours

instrument : (str)

Data set’s instrument name (default=’ampere’)

method : (str)

Method used to calculate the elliptical correction, accepts ‘median’ or ‘gaussian’. (default=’median’)

Returns:
r_corr : (float or array-like)

Radius correction in degrees at this MLT

References

Burrell, A. G. et al.: AMPERE Polar Cap Boundaries, Ann. Geophys., 38, 481-490, doi:10.5194/angeo-38-481-2020, 2020.

ocbpy.ocb_correction.harmonic(mlt, instrument='ampere', method='median')[source]

Return the results of a harmonic fit correction to the data boundary

Parameters:
mlt : (float or array-like)

Magnetic local time in hours

instrument : (str)

Data set’s instrument name (default=’ampere’)

method : (str)

Method used to determine coefficients; accepts ‘median’ or ‘gaussian’ (default=’median’)

Returns:
r_corr : (float or array-like)

Radius correction in degrees at this MLT

References

Burrell, A. G. et al.: AMPERE Polar Cap Boundaries, Ann. Geophys., 38, 481-490, doi:10.5194/angeo-38-481-2020, 2020.