Subject: Data Format Description for the IMP-J MAG15_V2_ASCII Data Set 
SPHE-00861 (73-078A-01O)
From: J. H. King
Organization: National Space Science Data Center

Entered as B52054 in NSSDC's Technical Reference File January, 2003. Modified 
January 14, 2003 from B46482 to show changes appearing in the replacement data
set SPHE-00861 (73-078A-01O).
Original (B46482) was for Mag15_ASCII datatype in NDADS, later moved to online 
access at .../15S_ASCII/ (Data Set ID = SPHE-00305 (73-078A-01M)).
Corrected 3/28/03 HKH.
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                  MAG15_V2_ASCII Format and Footnotes

Data Format for Tri-Axis Magnetometer 15.36 Second Magnetic Field Vectors

Data set is available for online access at 

ftp://nssdcftp.gsfc.nasa.gov/spacecraft_data/imp/imp8/mag/15s_ascii/

NSSDC Data Set ID: SPHE-00861
Old NSSDC ID: 73-078A-01O

Logical record size = 152 bytes
ITEM   Description      (Type)(Size)  Units      Notes
============================================================================
 1*    Year                   I5                  Four-digit year 
 2*    Day-of-year            I4      days        January 1 = 1
 3*    Seconds of day         F9.2    sec         Elapsed seconds of day
 4     Number of sequences    I3                  used for statistics
 5     Number of detail pts   I4
 6     X Geocentric SE pos.   F6.1    Earth radii
       of spacecraft
 7     Y Geocentric SE pos.   F6.1    Earth radii
       of spacecraft
 8     Z geocentric SE pos.   F6.1    Earth radii
       of spacecraft
 9     Y Solar Magnetospheric F6.1    Earth radii
       position of spacecraft
10     Z Solar Magnetospheric F6.1    Earth radii
       position of spacecraft
11     Field Magnitude (F1)   F8.2    nT          F1 = 1/n sum[F_i] for i=1,N
       (Averaged over 15.36                        where F_i is
       seconds)                                   computed over 1.28 seconds
12     B_X_SE Avgd. over      F8.2    nT          B_X_SE is the same as B_X_SM.
       15.36 seconds
13     B_Y_SE Avgd. over      F8.2    nT
       15.36 seconds
14     B_Z_SE Avgd. over      F8.2    nT
       15.36 seconds
15     B_Y_SM Avgd. over      F8.2    nT
       15.36 seconds
16     B_Z_SM Avgd. over      F8.2    nT
       15.36 seconds

Note: The new data set has Variances, themselves, instead of SQRT.

17     SQRT(Variance XX GSE)  F8.2    nT
18     SQRT(Variance YY GSE)  F8.2    nT
19     SQRT(Variance ZZ GSE)  F8.2    nT
20     SQRT(Variance YX GSE)  F8.2    nT
21     SQRT(Variance ZX GSE)  F8.2    nT
22     SQRT(Variance ZY GSE)  F8.2    nT
* Items 1 - 3 are for the last 1.28-second sequence included in the 
  15.36-second average computation.

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