Loading DMSP SSJ boundary files

Unlike the IMAGE and AMPERE boundaries, the DMSP SSJ boundaries are not included with the package. However, routines to obtain them are. To use them, you need to install the ssj_auroral_boundary package. Once installed, you can download DMSP SSJ data and obtain a boundary file for a specified time period. For this example, we’ll use a single day. You can download the files into any directory, but this example will put them in the same directory as the other OCB files.

import datetime as dt
import ocbpy
import os

stime = dt.datetime(2010, 12, 31)
etime = stime + dt.datetime(days=1)
out_dir = os.path.join(os.path.split(ocbpy.__file__)[0], "boundaries")

bfiles = ocbpy.boundaries.dmsp_ssj_files.fetch_format_ssj_boundary_files(stime, etime, out_dir=out_dir, rm_temp=False)

By setting rm_temp=False, all of the different DMSP files will be kept in the specified output directory. You should have three CDF files (the data downloaded from each DMSP spacecraft), the CSV files (the boundaries calculated for each DMSP spacecraft) and four boundary files. The boundary files have an extention of .eab for the Equatorial Auroral Boundary and .ocb for the Open-Closed field line Boundary. The files are separated by hemisphere, and also specify the date range. Because only one day was obtained, the start and end dates in the filename are identical. When rm_temp=True, the CDF and CSV files are removed.

You can now load the DMSP SSJ boundaries by specifying the desired filename, instrument, and hemisphere or merely the instrument and hemisphere.

# Load with filename, instrument, and hemisphere
south_file = os.path.join(out_dir, "dmsp-ssj_south_20101231_20101231_v1.1.2.ocb")
ocb_south = ocbpy.ocboundary.OCBoundary(filename=south_file, instrument='dmsp-ssj', hemisphere=-1)
print(ocb_south)

Open-Closed Boundary file: ~/ocbpy/ocbpy/boundaries/dmsp-ssj_south_20101231_20101231_v1.1.2.ocb
Source instrument: DMSP-SSJ
Open-Closed Boundary reference latitude: -74.0 degrees

21 records from 2010-12-31 00:27:23 to 2010-12-31 22:11:38

YYYY-MM-DD HH:MM:SS Phi_Centre R_Centre R
-----------------------------------------------------------------------------
2010-12-31 00:27:23 356.72 14.02 1.70
2010-12-31 12:27:56 324.82 0.86 0.65
2010-12-31 18:49:58 233.68 6.12 2.48
2010-12-31 22:11:38 318.60 4.64 4.26

Uses scaling function(s):
circular(**{})

# Load with date, instrument, and hemisphere
ocb_north = ocbpy.ocboundary.OCBoundary(stime=stime, instrument='dmsp-ssj', hemisphere=1)
print(ocb_north)

Open-Closed Boundary file: ~/ocbpy/ocbpy/boundaries/dmsp-ssj_north_20101231_20101231_v1.1.2.ocb
Source instrument: DMSP-SSJ
Open-Closed Boundary reference latitude: 74.0 degrees

27 records from 2010-12-31 01:19:13 to 2010-12-31 23:02:48

YYYY-MM-DD HH:MM:SS Phi_Centre R_Centre R
-----------------------------------------------------------------------------
2010-12-31 01:19:13 191.07 10.69 0.54
2010-12-31 06:27:18 195.29 13.52 0.35
2010-12-31 21:21:32 259.27 2.73 2.03
2010-12-31 23:02:48 234.73 3.94 1.38

Uses scaling function(s):
circular(**{})

The circular scaling function with no input adds zero the the boundaries, and so performs no scaling. At this point in time, the EAO boundaries are not used, but future versions of this package will grid data relative to both the OCB and EAO boundary.