regional_grid.nml

!
!***********************************************************************
!
! Parameter descriptions:
! ======================
!
! plon:
! ----
! Longitude (in degrees) of the center of the regional domain.
!
! plat:
! ----
! Latitude (in degrees) of the center of the regional domain.
!
! delx:
! ----
! Grid spacing (in degrees) in the x direction ON THE SUPERGRID.  Since
! the supergrid has twice the resolution of the actual grid, the grid 
! spacing in the x direction on the actual grid will be twice this re-
! solution.  
!
! The physical grid spacing del_dist_x in the x direction on the ACTUAL
! grid is related to delx by
!
!   del_dist_x = 2*delx*(circumf_Earth/360 deg)
!
! where circumf_Earth is the Earth's circumference, and the factor of 2
! appears due to delx being the grid angle in the x direction on the su-
! pergrid.  Since circumf_Earth = 2*pi*radius_Earth, then solving the 
! above for delx gives
!
!   delx = (del_dist_x/(2*radius_Earth))*degs_per_radian
!
! where degs_per_radian = (360 deg/2*pi).  For example, to obtain a grid
! with a del_dist_x =  3 km actual grid spacting, we must use
!
!   delx = (3 km/(2*6371 km)*(360 deg/(2*pi))
!        = 0.0135 deg
! dely:
! ----
! Grid spacing (in degrees) in the y direction ON THE SUPERGRID.  Since
! the supergrid has twice the resolution of the actual grid, the grid 
! spacing in the y direction on the actual grid will be twice this re-
! solution.  
!
! lx:
! --
! Negative of the number of cells in the x direction ON THE SUPERGRID 
! from the lower-left corner of the regional domain to the grid center.
! Thus, if nx_SG is the number of cells on the supergrid in the x direc-
! tion, this is simply -nx_SG/2.  Since the number of cells on the su-
! pergrid is twice the number of cells on the actual grid, i.e. nx_SG =
! 2*nx where nx is the number of points on the actual grid, then this 
! becomes 
!
!   lx = -nx_SG/2 = -(2*nx)/2 = -nx
!
! To include a halo region of width nhalo cells (where the cells are 
! counted on the actual grid), set this to
!
!   lx = -(nx + 2*nhalo)
!
! and include nhalo in the calculation of ly, i.e.
!
!   ly = -(ny + 2*nhalo)
!
! where ny is the number of cells in the y direction on the actual grid.
! The factor of 2 multiplying nhalo in the above two expressions appears
! because the halo is present on both sides of a given direction (e.g.
! both west and east, both south and north, etc).
!
! ly:
! --
! Analogous to lx but in the y direction.
!
! pazi:
! ----
! Rotation angle for the ESG grid in degrees.
!
!***********************************************************************
!

&regional_grid_nml
  plon = <plon>
  plat = <plat>
  delx = <delx>
  dely = <dely>
  lx   = <lx>
  ly   = <ly>
  pazi = <pazi>
/