This document has been modified/extracted from the original Journal
article on Universal Format.  Editorial modifications are noted in
[square brackets].    RAR 10/2000


The original report can be found in:

	Barnes, Stanley L, 1980: Report on a meeting to establish a
	common Doppler radar data exchange format.
	The Bulletin of the American Meteorological Society, Vol 61, 
	    No. 11, pp1401-1404. Nov 1980


                  Universal Format Radar Tape Structure
		  =====================================
                  

Universal format tapes conform to the following five specification:

 1. 9 track tapes, 1600 or 6250 cpi density. [Now extended to other media]
 2. 16-bit words, signed integers, 2's complement.
           [Note that words are "big-endian" (most significant byte at end of word)]
 3. Physical records, length <= 4095 words.  [Record lengths now < 65536 bytes.]
 4. File marks between volume scans (volumes).
 5. ASCII words are left justified, blank filled.


MANDATORY HEADER BLOCK

  Word
    1   UF (ASCII)
    2   Record length (16-bit words)
    3   Position of first word of nonmandatory header block.  (If no
         nonmandatory header block exists, this points to the first
         existing header block following the mandatory.  In this way,
         word (3) always gives 1 + the length of the mandatory header.
    4   Position of first word of local use header block.  (If no local
          use headers exist, this points to the start of the data
          header block.)
    5   Position of first word of data header block
    6   Physical record number relative to beginning of file
    7   Volume scan number relative to beginning of tape
    8   Ray number within volume scan
    9   Physical record number within the ray (one for the first
         physical record of each ray)

   10   Sweep number within this volume scan
11-14   Radar name (8ASCII characters, includes processor ID.)
15-18   Site name (8 ASCII characters)
   19   Degrees of latitude (North is positive, South is negative)
   20   Minutes of latitude
   21   Seconds (x64) of latitude
   22   Degrees of longitude (East is positive, West is negative)
   23   Minutes of longitude
   24   Seconds (x64) of longitude (Note:  minutes and seconds have same
         sign as degrees.)
   25   Height of antenna above sea level (meters)
   26   Year (of data)  (last 2 digits)
   27   Month
   28   Day
   29   Hour
   30   Minute
   31   Second
   32   Time zone (2 ASCII -- UT, CS, MS, etc.)
   33   Azimuth (degrees x 64) to midpoint of sample
   34   Elevation (degrees x 64)
   35   Sweep mode:  0 - Calibration
                     1 - PPI (Constant elevation)
                     2 - Coplane
                     3 - RHI (Constant azimuth)
                     4 - Vertical
                     5 - Target (stationary)
                     6 - Manual
                     7 - Idle (out of control
   36   Fixed angle (degrees x 64) (e.g., elevation of PPI; azimuth
          of RHI; coplane angle)
   37   Sweep rate (degrees/seconds x 64)
   38   Generation date of common format - Year
   39   Month
   40   Day
41-44   Tape generator facility name (8 character ASCII)
   45   Deleted of missing data flag (Suggest 100000 octal)


OPTIONAL HEADER BLOCK

  Word
  1-4   Project name (8 ASCII)
    5   Baseline azimuth (degrees x 64)
    6   Baseline elevation (degrees x 64)
    7   Hour (start of current volume scan)
    8   Minute (start of current volume scan)
    9   Second (start of current volume scan)
10-13   Field tape name (8 ASCII)
   14   Flag (= 0 if number of range gates, R min, and spacing are the
          same for all data within this volume scan; = 1 if these are
          the same only within each sweep; = 2 if these are the same
          only within each ray).


LOCAL USE HEADER BLOCK

  Any use, any contents


DATA HEADER

  Word
    1   Total number of fields this ray
    2   Total number of records this ray
    3   Total number of fields this record
    4   1st field name (2 ASCII): e.g., VE - velocity (m/s)
                                        SW - spectral width (m/s)
                                        DM - reflected power dB(mW)
                                        DZ - dB(Z)
                                        etc.
    5   Position of 1st word of 1st field header
    6   2nd field name
    7   Position of 1st word of 2nd field header
   etc.


FIELD HEADER

  Word
    1   Position of first data word
    2   Scale factor (meteorological units = tape value divided by
         scale factor)
    3   Range to first gate (km)
    4   Adjustment to center of first gate (m)
    5   Sample Volume spacing (m)
    6   Number of sample volumes
    7   Sample volume depth (m)
    8   Horizontal beam width (degrees x 64)
    9   Vertical beam width (degrees x 64)
   10   Receiver bandwidth (MHz)
   11   Polarization transmitted (0 = horizontal; 1 =vertical;
         2 = circular; >2 = elliptical)
   12   Wavelength (cm x 64)
   13   Number of samples used in field estimate
   14   Threshold field (e.g., DM) (2 ASCII)
   15   Threshold value
   16   Scale
   17   Edit code (2 ASCII)
   18   Pulse repetition time (microseconds)
   19   Bits per sample volume (16 for exchanged tape)
 20-?   Words for individual fields, as follows

  for VF, VE, VR, VT, VP:
  word
   20   Nyquist velocity (scaled)
   21   FL (2 ASCII) if flagged in least significant bit with
         NCAR bad velocity flag (1 = good, 0 = bad)

  for DM:
  word
   20   Radar constant = RC, such that dB(Z) = [ (RC + DATA/SCALE] +
          20log(range in km)
   21   Noise power (dB(mW) x scale)
   22   Receiver gain (dB x scale)
   23   Peak power (dB(mW) x scale)
   24   Antenna gain (dB x scale)
   25   Pulse duration (microseconds x 64)