aareadme file at
ftp/spacecraft_data/explorer/explorer33/plasma_probe/3-min_interplanetary_plasma_param/
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This directory provides access to 1966-1971 annual files of
3-min plasma parameter data in ASCII format, from the MIT
instrument flown on Explorer 33. In addition, the directory
provides access to two subdirectories of the same data but
as taken directly from magnetic tapes submitted to NSSDC in
EBCDIC format years ago and ingested through NSSDC's DIOnAS
process. The ASCII data set was created by GSFC's Space
Physics Data Facility in 2008.
The format of the ASCII data set is:
FORMAT =
(I4,F10.5,A4,I3,2I3.2,I7,F6.1,I4,2F6.1,I4,4F6.1,I4,2F6.1)
Characters Format Description
1-4 I4 Year (1966 . 1971)
5-14 F10.5 Decimal day of year (Jan. 1 at 12UT
is 0.5)
15-18 A4 Month (JAN . DEC)
19-21 I3 Day of month (1 . 31)
22-24 I3 Hour of day (0 . 23)
25-27 I3 Minute of hour (0 . 59)
28-34 I7 Spacecraft counter value
35-40 F6.1 Ion density (number/cc)
41-44 I4 Aberrated flow speed (km/s)
45-50 F6.1 Aberrated flow longitude (deg) (see
note)
51-56 F6.1 Aberrated flow latitude (deg) (see
note)
57-60 I4 Thermal speed (km/s)
61-72 2F6.1 Flow angles, spacecraft
coords, not normally used
73-78 F6.1 True longitude of flow (see note)
79-84 F6.1 True latitude of flow (see note)
85-88 I4 True flow speed
89-94 F6.1 Solar ecliptic longitude of s/c spin axis
95-100 F6.1 Solar ecliptic latitude of s/c spin axis
Note: Flow angles give the GSE directions from which the
flow comes. "Aberrated" directions are as observed. "True"
directions are with the 30 km/s motion of the Earth (and its
orbiting spacecraft) about the sun removed.
Note: As of this writing (October, 2008), Explorer 33
ephemeris data are neither contained in this plasma data set
nor are they otherwise online at NSSDC or, to our knowledge,
elsewhere. However NSSDC has such data still offline; they
will be made network-accessible in due course, but if you have
a desire to use them in support of these plasma data,
call the NSSDC Director at 301-286-7355.
The following material was created specifically in support
of the EBCDIC data set in the subdirectories under this
directory.
The two subdirectories of this directory each has one tarred
file and a subdirectory
with one "attribute file" carrying technical information
about the tarred file. One subdirectory is for data from
mid-1966 to early-1970 and the other for early-1970 to late-1971.
These tarred files were each made from one magnetic
tape, where these two tapes had each been made by
concatenating contents of multiple smaller-capacity,
MIT-provided tapes.
The data of the PI-supplied tapes were in ASCII-like EBCDIC
form. Details of bit sequences in EBCDIC's 8-bit representations
is available at
http://nssdc.gsfc.nasa.gov/nssdc/formats/EBCDIC_Codes.htm
The 3-min-resolution data contained in each record are:
time, ion density and thermal speed, and flow velocity vectors
with and without the effects of aberration
due to the Earth's ~30 km/s circumsolar motion. Details on
the sequence and formats of the data words in the EBCDIC records
is found at
ftp://nssdcftp.gsfc.nasa.gov/staging/review_08/all_catalogs/dsc_0168.pdf
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