Boundary Data Sets

Poleward (OCB) and Equatorward Auroral Boundaries (EABs) must be obtained from observations or a model for this coordinate transformation. The standard OCB and EAB data sets can be found in ocbpy/boundaries, though this location may also found using ocbpy.boundaries.files.get_boundary_directory(). Currently, three different boundary data set types are available. Not all data sets include the locations of the EAB. Routines to retrieve boundary filenames from specific instruments, time periods, hemispheres, and boundary types are provided in the ocbpy.boundaries.files sub-module.

IMAGE

Data from three auroral instruments provide northern hemisphere poleward auroral boundary (PAB) and EAB locations for 3 May 2000 02:41:43 UT - 31 Oct 2002 20:05:16, though not all of the times included in these files contain high-quality estimations of the boundary locations. Recommended selection criteria are included as defaults in the OCBoundary class. There are also boundary files that combine the information from all instruments to obtain the OCB and EAB. These combined files are the default boundaries for the IMAGE time period. You can read more about the OCB determination, EAB determination, this selection criteria, and the three auroral instruments (IMAGE Wideband Imaging Camera (WIC) and FUV Spectrographic Imagers SI12 and SI13) in the articles listed in IMAGE FUV Boundaries.

The most recent corrects for each instrument that add the DMSP particle precipitation corrections to the PAB and EAB locations are included in ocbpy.ocb_correction. These corrections should be applied to the data used to obtain the circle fits included in the instrument files, not the circle fits themselves. These data sets may be obtained from the British Antarctic Survey.

AMPERE

OCB data sets can also be obtained from AMPERE (Active Magnetosphere and Planetary Electrodynamics Response Experiment) R1/R2 Field-Aligned Current (FAC) boundary data. This data is provided for both hemispheres between 2010-2016, inclusive. Because there is an offset between the R1/R2 FAC boundary and the OCB, a correction is required. This correction can be implemented using the routines in ocbpy.ocb_correction. More information about the method behind the identification of these boundaries and their offset can be found in the articles listed in AMPERE Boundaries. Recommended selection criteria are included as defaults in the OCBoundary class.

DMSP SSJ

DMSP particle precipitation instruments make it possible to identify the poleward and equatorward boundaries of the auroral oval along the satellite orbit. Details about this identification process can be found in the references listed in DMSP SSJ Boundaries. Routines to download and proceess the DMSP boundary files are provided in the ocbpy.boundaries.dmsp_ssj_files sub-module.

Boundaries Module

Boundary file utilities.

Boundary Files

Functions that support boundary file selection.

ocbpy.boundaries.files.get_boundary_directory()[source]

Get the OCBpy boundary directory.

Returns:boundary_dir – Directory holding the boundary files included in OCBpy
Return type:str
ocbpy.boundaries.files.get_boundary_files(bound='ocb')[source]

Get boundary filenames and their spatiotemporal ranges.

Parameters:bound (str) – String specifying which boundary is desired (OCB or EAB) (default=’ocb’)
Returns:boundary_files – Dict with keys of boundary files containing dicts specifying the hemisphere, instrument, file start time, and file end time
Return type:dict

Notes

IMAGE instruments may be separated into WIC, SI12, and SI13. If IMAGE is desired, the combined file will be used.

Unknown instruments should have filenames of the format, instrument_hemisphere_%Y%m%d_%Y%m%d.boundary

ocbpy.boundaries.files.get_default_file(stime, etime, hemisphere, instrument='', bound='ocb')[source]

Get the default file for a specified time and hemisphere.

Parameters:
  • stime (dt.datetime or NoneType) – Starting time for which the file is desired; if None, will prioritize IMAGE data for the northern and AMERE data for the southern hemisphere
  • etime (dt.datetime or NoneType) – Ending time for which the file is desired; if None, will prioritize IMAGE data for the northern and AMPERE data for the southern hemisphere
  • hemisphere (int) – Hemisphere for which the file is desired (1=north, -1=south)
  • instrument (str) – Instrument that provides the data. This will override the starting and ending times. Accepts ‘ampere’, ‘amp’, ‘image’, ‘si12’, ‘si13’, ‘wic’, ‘dmsp-ssj’, and ‘’ (to accept instrument defaults based on time range). Will also accept the instrument name for any instrument whose boundary file follows the naming convention INST_HEMI_YYYYMMDD_YYYYMMDD_*.BBB, where: INST = instrument name HEMI = north or south YYYYMMDD = starting and ending year, month, day BBB = ocb or eab (default=’’)
  • bound (str) – String specifying which boundary is desired (OCB or EAB) (default=’ocb’)
Returns:

  • default_file (str or NoneType) – Default filename with full path defined or None if no file was available for the specified input constraints
  • instrument (str) – Instrument for the default file (either ‘ampere’, ‘image’, or ‘dmsp-ssj’)

DMSP SSJ Files