CALL SEQUENCE...
       gwtqd  GGBIGU GGBIGV SPVORT SPDIV INPUT OUTPUT [-lrt VAL1  -lmt  VAL2
                                                       -ktr VAL3  -kuv [VAL4]
                                                       -npg VAL5]
 
 
      DESCRIPTION...
       gwtqd  - COMPUTES SPECTRAL Q,D FROM GRID WINDS 
  
 
      AUTHORS - B.Dugas AND J.D.Henderson, fev 22/85.
      LAST REVISION: $Header: Corrections-pour-IFORT16-et-bugfix-pour-GSASG @ Mon, 26 Jun 2017 13:03:30 -0400 (dugas) $
  
 
      PURPOSE - COMPUTES THE SPECTRAL COEEFICIENT FILES FOR VORTICITY AND 
                DIVERGENCE FROM WIND COMPONENTS ON GAUSSIAN GRIDS. 
 
      NOTES: 1) WIND INPUT MAY BE REAL WIND OR MODEL WIND, WHERE THE 
                MODEL WIND COMPONENTS ARE DEFINED AS:
 
                             (U,V)*COS(LAT)/(EARTH RADIUS).
             2) A) IF GGBIGU'S INTERNAL NAME IS 'U' OR GGBIGV'S INTERNAL
                   NAME IS 'V', THEIR UNITS ARE ASSUMED TO BE IN M/S.
                B) IF GGBIGU'S INTERNAL NAME IS 'UU' OR GGBIGV'S INTERNAL
                   NAME IS 'VV', THEIR UNITS ARE ASSUMED TO BE IN KNOTS.
                C) IF NEITHER A) AND B) APPLY, THE INPUT FILE TYPES
                   DETERMINE THE UNITS IN THE FOLLOWING MANNER:
                   - AT LEAST ONE RPN 1989 STANDARD FILE = KNOTS
                   - ANYTHING ELSE                       = M/S
                WHEN THE INPUT VARIABLES ARE IN UNITS OF KNOTS, THEY
                ARE CONVERTED TO M/S DURING THE CALCULATIONS.
 
 
      INPUT FILES... 
       GGBIGU = GLOBAL GAUSSIAN GRIDS OF U WIND COMPONENTS. 
       GGBIGV = GLOBAL GAUSSIAN GRIDS OF V WIND COMPONENTS. 
  
      OUTPUT FILES... 
       SPVORT = SPECTRAL VORTICITY 
       SPDIV  = SPECTRAL DIVERGENCE 
  
 
      INPUT PARAMETERS... 
  
       LRT,LMT = N,M TRUNCATION WAVE NUMBERS 
       KTR     = SPECTRAL TRUNCATION TYPE 
       KUV     = 0, ASSUMES MODEL WINDS (PRIMARY DEFAULT),
               = 1, ASSUMES TRUE WINDS (SECONDARY DEFAULT).
       NPG     = OUTPUT PACKING DENSITY. BLANK INPUT MEANS
                 THAT THE PROGRAM USES AT LEAST 32 BITS AND
                 PERHAPS MORE IF GGBIGU USES MORE THAN THAT.
 
       READ( 5,5010 ) LRT,LMT,KTR,KUV,NPG
 5010  FORMAT(10X,5I5) 
  
      COMMENTS CONCERNING THE USAGE OF KUV...
 
       SPECTRAL PROJECTIONS OF VECTOR COMPONENTS SHOULD ONLY BE
       CARRIED ON SO-CALLED MODEL COMPONENTS, WHICH ARE ASSUMED
       THE BE THE REAL WINDS MULTIPLIED BY 
 
                   COS( LAT )/( EARTH RADIUS ).
 
       THE MODEL WINDS ARE THUS CONTINUOUS AT THE POLES AND CAN THEN
       BE CORRECTLY PROJECTED. THE NORMAL MODE OF OPERATION ASSUMES
       THE PRESENCE OF SO-CALLED MODEL WINDS AND DOES NO CONVERSIONS.
 
 
      EXAMPLE OF INPUT CARD... 
  
     GWTQD   20   20    2    0  -32
 
         0123456789012345678901234567890123456789012345678901234567890
         1         2         3         4         5         6         7
 
 
      EXIT CONDITIONS...
        0 NO PROBLEMS
        1 INPUT ARRAY IS NOT A GLOBAL GRID
        2 PROBLEM UNPACKING FIRST ARRAY IN GGBIGU
        3 NOT AS MANY ARRAYS IN GGBIGV AS IN GGBIGU
        4 DIFFERENT SIZE ARRAYS FOR U AND V
        5 ERROR ABORT READING INPUT
        6 PREMATURE EOF ON GGBIGU
        7 INPUT VARIABLE NAME MISMATCH
        8 UNABLE TO ALLOCATE WORKING MEMORY