Document title: Readme.txt for DE-2 Unified Abstract data on NDADS
Project: DE
NDADS Datatype: UA           
Super-EID: DOCUMENT                      
There may be other documents also identified by this super-EID.
NDADS filename: DE2_UA_README.DOC
TRF entry B46567.txt in NSSDC's controlled digital document library. Feb. 1998.
Document text follows:
----------------------

                 DE-2 Unified Abstract data on NDADS
                 ___________________________________

The Dynamics Explorer 2 (DE-2) Unified Abstract (UA) files contain
data at 16 second time resolution from the following DE-2 experiments:
Neutral Atmospheric Composition Spectrometer (NACS), Wind and 
Temperature Spectrometer (WATS), Fabry-Perot Interferometer (FPI),
Retarding Potential Analyzer (RPA), and the Langmuir Probes (LANG).   

The UA daily files are requested with the ENTRY_ID = UAyyddd and are
than staged/stored as DEUAyyddd.DAT files; yy is the year and ddd the 
day of the year. 

A SOFTWARE request will stage the following software files OAREAD4.FOR,
UREAD.FOR, UROPEN.FOR, TEST.FOR and also the data base of selected orbit 
parameters OABASE.DAT (about 6 MB). The UROPEN, OAREAD and UREAD subroutines 
included in these files provide easy access to the DEUAyyddd.DAT files 
as illustrated in the TEST program. UROPEN, OAREAD and UREAD are explained 
in more detail below.

A DOCUMENT request will stage the following documents: a listing of 
parameter availability for each day (DEUACAT.DAT), a listing of all data, 
software and documentation files that constitute this data set including 
the block size of each file (DEUAOA.LIS), and this file (README.TXT).

----------------------------------------------------------------------
      			Format of DEUAyyddd Files
----------------------------------------------------------------------

Files are written in unformatted VAX binary as daily files with the 
record length (fixed for any given day) depending on the available data.

Word    First Record                Other Records
----    ------------------------    -----------------------
   1    NW*100000+YYDDD (integer)   Time (integer millisec)
   2    Word code 1 (integer)       Data for code 1 (real)
   3     "    "   2    "              "   "    "  2   "
   |
   |
NW+1     "    "   NW   "              "   "    " NW   "


The available parameters and correlated code numbers are:

	1 NACS N2	density				cm-3
        2 NACS O	density				cm-3
        3 NACS HE	density				cm-3
        4 NACS AR	density				cm-3
        5 NACS N	density				cm-3
        6 WATS TN	neutral temperature		K
        7 WATS NVE	eastward neutral wind		m/s
        8 WATS NVU	upward neutral wind		m/s
        9 LANG NP	plasma density			cm-3
       10 LANG TE	electron temperature		K
       11 FPI FWAV	wavelength			Angstrom
       12 FPI FALT	tangent altitude		km
       13 FPI FVN	northward neutral wind		m/s
       14 FPI FTEM	neutral temperature		K
       15 FPI RAY	intensity			Raleighs
       16 RPA TI	ion temperature			K
       17 RPA NI	total ion density		cm-3
       18 RPA IVE	eastward ion drift		m/s
       19 RPA IVN	northward ion drift		m/s
       20 RPA IVU	upward ion drift		m/s

File DEUACAT.DAT contains a list of days and geophysical data (code
numbers) available on that day (TYPE DEUACAT.DAT).


----------------------------------------------------------------------
      		Software for DEUAyyddd Files
----------------------------------------------------------------------

Three subroutines (UROPEN, UREAD, OAREAD) are available to aid in 
accessing the UA data (UROPEN, UREAD) and the orbit/attitude data
(OAREAD). They use I/O unit numbers in the range 91 to 99. The logical 
SYS$UA must be ASSIGNED to the directory containing the DEUAyyddd.DAT 
files and the logical SYS$OA should be ASSIGNED to the directory
containing the file OABASE.DAT.

UROPEN: Initiate read operations.

      CALL UROPEN(FDATE,FTIME,IERR,MAP)

       Input parameters:
        FDATE - First date (YYDDD) for data (INTEGER).
        FTIME - First time (Millisec) for data (INTEGER).
        MAP   - array containing number of data items to be
                retrieved plus list of the data item code numbers.

       Output parameters:
        IERR - Error return:
               3XX Open error with XX VAX error code;
               800 No data within 20 days of request;
               900 No further data.

UREAD: Read sequentially.

      CALL UREAD(IDATE,ITIME,IERR,DATA)

       Output parameters:
        IDATE - Date of data (YYDDD).
        ITIME - Time of data (Millisec).
        IERR  - Error return:
                3XX Open error with XX VAX error code;
                400  Read error;
                800 No data within 20 days of request;
                900 No further data.
        DATA  - Array of data according to map established
                in call to UROPEN.


OAREAD: to get orbit data

      CALL OAREAD(IDATE,ITIME,IERR,MAP,DATA)

       Input parameters:
        IDATE - Date of data (YYDDD).
        ITIME - Time of data (Millisec).
        MAP   - Array containing number of required parameters
                plus list of parameters 
                13 Orbit number
                32 Altitude
                33 Latitude
                34 Longitude
                37 Local Solar Time
                38 Local Magnetic Time
                39 L Shell
                40 Invariant Latitude
                76 Solar Zenith Angle
		(A full list of o/a parameters and associated code 
		numbers is listed in OA_PARAMETER.LIS).
       Output parameters:
        IERR  - Error return from file open
          	ierr = -20 means gap in data prevented interpolation 
		(may not occur)
         	ierr = -21 means read error from OABASE.DAT (probably
                trying to access non-existant record)
        DATA  - Array of data according to MAP