Document title: Format description for the PI-provided DE WATS 2-second data
Project: DE
NDADS Datatype: WATS_2S_ASCII 
EID: DOCUMENT
Super-EID: DOCUMENTS
There may be other documents also identified by this super-EID.
NDADS filename: wats_format_sfdu_de.doc
TRF entry: b47607.txt in NSSDC's controlled digital document library, Dec. 1998.
Document text follows:
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CCSDYDNM000200NSSDjjjjSMRK0001

TYPE_OF_FILE_NAME: WATS TEMPERATURE AND WIND

FILE_ATTRIBUTES: Sequential, unformatted, two record types, fixed length
records, blocked with blocksize 2024 bytes.  Placed in 3 tapes labeled WATSn, in
backup format, in backup files named WATSn.BCK where n is 1,2, or 3
depending upon the tape number.

TYPE_OF_FILE_DESCRIPTION:

Each file corresponds to an original Sigma 9 MAF file.  Each logical record of
the file has ambient temperature and winds obtained in a two second slot.  File
names are of the form D[orbit number]N, where: the letter D is at the
beginning of all files, the orbit number contains leading zeros if needed to
force it to be 4 digits long, and N is a sequence number within a given orbit
from 0 to 9 to ensure unique file names.

FILE_STRUCTURE:

The files are written as VAX unformatted sequential with logical records of
equal length.

RECORD_TYPE_NAMES: Horizontal, Vertical -- Only one of the two baffles may
be operating at one time, and the one operating in a given 2 second
measurement slot determines the record type.

RECORD_TYPES:

RECORD_TYPE NAME: Horizontal

FIXED_RECORD_TYPE_LENGTH: 44 bytes

FORMAT_OF_THE_LOGICAL_RECORD:



    WORD      FIELD NAME   TYPE   DESCRIPTION

   NUMBER                  I/R


     1        DATE         VI4    Date in YYDDD, YY = last 2 digits of
                                  the year, DDD=day number (Jan 1 = 1)

     2        TIME         VI4    Universal time of day in milliseconds

     3        MODE         VI4    Values 3 or 4 indicates horizontal

     4        OUTIN        VI4    1 = baffle going out and 0 = going in.
                                  (This field is used by the correction
                                   program to correct systematic wind errors
                                  that are a function of the baffle direction.)

     5        MASS         VI4    Mass in AMU, usually 28 or 32,
                                  (Mass 32 measured indicates ambient mass
                                  16 which is recombined in the instrument.)

     6        DENSITY      VR4    Density in number per cc

     7        TEMPERATURE  VR4    Temperature in degrees Kelvin

     8        VELOCITY     VR4    Horizontal (zonal) velocity in
                                  spacecraft coordinates in meters
                                  per second, with plus in the plus
                                  Z-axis direction.

    9 byte 1  TIME1        VI1    Baffle optical pulse 1 readout.
                                  (This field is used by the correction
                                  program to correct systematic errors that
                                  are a function of the baffle position.)

   9 byte 2   TIME2        VI1    Baffle optical pulse 2 readout.
                                  (This field is used by the correction
                                  program to correct systematic errors that
                                  are a function of the baffle position.)

   9 byte 3   SLOT         VI1    The slot position ( 1 through 4) in the  4 slot 	
                                  mode sequence.  This field is used by the
                                  correction program to correct systematic
                                  errors that  are a function of the sequence of
                                  modes.

   9 byte 4   MODE         VI1    The mode which is unpacked and
                                  placed in word 3 for convenience.

 10 byte 1,2  COUNTS1      VI2    (Counts + Background) / 8

 10 byte 3,4  COUNTS2      VI2    Counts / 8
                                  The instrument counting level is
                                  used to calculate the statistical error.

 11           VELOCITY     VR4    Horizontal (zonal) velocity in
                                  corotating Earth frame in meters
                                  per second with plus in the east
                                  direction.


The field names DENSITY,TEMPERATURE, and VELOCITY refer to parameters
whose values have been packed into DEC VAX 4-byte reals designated type VR4.
The field names DATE, TIME, MODE, OUTIN, and MASS refer to parameters whose
values have been packed into DEC VAX 4-byte INTEGERS designated type VI4.
The type VI1 indicates one byte unsigned integers and VI2 indicates two byte
unsigned integers.  The horizontal and vertical records differ only in the type
of velocity put into word 11.

FIELD_RANGE:

The allowed range of TEMPERATURE is 200 to 3000 degrees Kelvin and the
allowed range of zonal VELOCITY is -3000 to 3000 meters per second.

FIELD_RELATIONSHIPS:

TIME: The time value from the TIME field corresponds to the midpoint of the
two second slot interval used to compute the temperature and velocity. The
statistical error is given by



        ST/T = 1.3 / SQRT(C)

and

        SV = 260 / SQRT(C)  m/s



where ST is the standard deviation of the temperature, T is the temperature, C
is the counts as given in word 10, and SV is the standard deviation of the
velocity.

RECORD_TYPE NAME: Vertical

This record type is identical to the horizontal type except that the mode is 5 or
6, and the velocity is vertical with the plus direction defined as the plus Y axis
in spacecraft coordinates, and the up direction in geographical coordinates.
The allowed range of vertical velocity is -600 to 600 meters per second.

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