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c     ######                                                      ######
c     ######                     BNDRY.INC                        ######
c     ######                                                      ######
c     ######                     Developed by                     ######
c     ######     Center for Analysis and Prediction of Storms     ######
c     ######                University of Oklahoma                ######
c     ######                                                      ######
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c     PURPOSE:
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c     Include file 'bndry.inc' for ARPS 
c
c     Boundary condition parameters for the east, west, north, 
c     south, top and bottom boundaries. 
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c     AUTHOR: Ming Xue
c     10/01/1991
c
c     MODIFICATION HISTORY:
c
c     7/25/92 (MX)
c     Added parameter rbcopt
c
c     7/29/97.  Dan Weber
c     Added fftopt for distingushing the type of FFT used in the upper
c     radiation condition.
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      integer lbcopt ! Lateral boundary condition option;
                     ! = 1, for internal determined LBC
                     ! = 2, for externally forced LBC

      integer ebc    ! east   boundary condition option.
      integer wbc    ! west   boundary condition option.
      integer nbc    ! north  boundary condition option.
      integer sbc    ! south  boundary condition option.
      integer tbc    ! top    boundary condition option.
      integer bbc    ! bottom boundary condition option.
      integer fftopt ! FFT option for tbc=4 configuration.
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c     The boundary conditions are defined independent of each
c     boundary, but should be consistent. 
c
c     When the value of the above parameters is:
c     = 1, rigid wall boundary condition 
c     = 2, periodic boundary condition 
c     = 3, zero gradient boundary condition (specified for all variables) 
c     = 4, radiation (open) boundary condition 
c     = 5, user specified boundary conditon (externally) 
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      integer rbcopt ! Radiation lateral boundary condition option:
                     ! = 1, Klemp & Wihelmson type with constant phase 
                     !      speed c = c_phase
                     ! = 2, Orlanski type, with estimated phase speed c

      common /bccntl/ lbcopt, ebc,wbc,nbc,sbc,tbc,bbc,rbcopt,fftopt

      real c_phase   ! Fixed phase speed of waves propagating out of 
                     ! lateral boundary. Used by option rbcopt=1. 
      common /c_gwsped/ c_phase

      real rlxlbc    ! Inflow boundary relaxation coefficient.
      common /relaxbc/ rlxlbc

      integer pdetrnd   ! Option for detrending pressure
      common /pdetrend/ pdetrnd