OCB Data Sets

OCBs must be obtained from observations for this coordinate transformation. The standard OCB 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. Some data sets also include the locations of the Equatorward Auroral oval Boundary (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 OCB locations for 3 May 2000 03:01:42 UT - 22 Aug 2002 00:01:28, though not all of the times included in these files contain high-quality estimations of the OCB. Recommended selection criteria are included as defaults in the OCBoundary class. You can read more about the OCB determination and this selection criteria, as well as the three auroral instruments (IMAGE Wideband Imaging Camera (WIC) and FUV Spectrographic Imagers SI12 and SI13) in the articles listed in IMAGE FUV Boundaries.

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.

Boundary File Module

Provide desired boundary file names

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 are separated into WIC, SI12, and SI13 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 File Module