global_model_grids.f90

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module global_model_grids
  
   implicit none
  
  real ::  ice_grid( 0:719, 0:359, 1)
  real :: ozn_grid(0:359, 0:180, 1)
 
 
  logical  :: grids_are_read
  logical :: icec_is_read
  logical :: nise_is_read
  logical :: snow_stats_are_read = .false.
  
  type ancillary_type
 
    real, dimension(:), allocatable :: mixr_profile
    real, dimension(:), allocatable :: temp_profile 
    real, dimension(:), allocatable :: height_profile
    real, dimension(:), allocatable :: pressure_profile
    real, dimension(:), allocatable :: o3_profile
  
    
    real :: wind_speed
    real :: ts
    real :: ps
    real :: col_o3
        
    real :: seaice_fraction
    real :: snow_fraction
    
    integer*1 :: surface_level
    integer*1 :: trop_level
    integer*1 :: lsm
    
  end type ancillary_type
  
contains
 
    subroutine get_model_idx(lat, lon, i, j) 
 
 
        real, intent(in) :: lat, lon
        integer, intent(inout ) :: i,j
 
        real :: x,y, x0, dx, y0, dy
    
        x = min( max( lon,  -179.99 ), 179.99 )
        if( x > -999. .and. x < 0.0 ) x = lon+ 360.0
        x0 = 0.0
        dx = 1.0
        i = int( ( x - x0 + 0.5*dx ) / dx ) 
 
        if( i .eq. 360 ) i = 0
 
        y = min( max( lat, -89.99 ), 89.99 )
        y0 = 90.0
        dy = -1.0
        j = int( ( y - y0 + 0.5*dy ) / dy )
 
        i = i+1
        j = j+1
 
 
    end subroutine get_model_idx
  
 
    subroutine get_model_idx_geos5(grid_xstart, grid_ystart, lat, lon, model_i, model_j)
 
        integer, intent(in) :: grid_xstart, grid_ystart
        real, intent(in) :: lat, lon
        integer, intent(inout) :: model_i, model_j
 
        real :: minLat, maxLat, minLon, maxLon
        real, parameter :: dlon = 0.625 ! 5/8
        real, parameter :: dlat = 0.5
 
        model_i = int((lon + 180) / dlon ) - grid_xstart 
        model_j = int((lat + 90) / dlat + 1 ) - grid_ystart 
        
        if (model_i < 1) model_i = 1
        if (model_j < 1) model_j = 1
        
    end subroutine get_model_idx_geos5
 
    subroutine find_geos5_bounds(istart, iend, jstart, jend, lat, lon)
 
        integer, intent(inout) :: istart, iend, jstart, jend
        real, dimension(:,:), intent(in) :: lat, lon
 
        real :: minLat, maxLat, minLon, maxLon
        real, parameter :: dlon = 5./8.
        real, parameter :: dlat = 0.5
 
 
        minlat  = minval( lat,  mask = ( (lat  >= -90.0000 .and. lat  <= 90.00000) ) )
        maxlat  = maxval( lat,  mask = ( (lat  >= -90.0000 .and. lat  <= 90.00000) ) )
 
        minlon = minval( lon, mask = ( (lon >= -180.000 .and. lon <= 180.0000) ) )
        maxlon = maxval( lon, mask = ( (lon >= -180.000 .and. lon <= 180.0000) ) )
                
        istart = int((minlon + 180) / dlon ) 
        if (istart < 0) istart = 0
        iend = int((maxlon + 180) / dlon ) 
        if (iend > (360/dlon-1)) iend = 360/dlon - 1
        
        jstart = int((minlat + 90) / dlat )  
        jend = int((maxlat + 90) / dlat ) 
                
                
    end subroutine find_geos5_bounds
 
    real function get_W(RH, T, P)
 
! After Rogers and Yau. 
 
        real*8, intent(in) :: rh, t, p
 
        real, parameter :: c = 4187.    
        real, parameter :: cpv = 1870.
        real, parameter :: l0 = 2.501e6
        real, parameter :: t0 = 273.
    
        real :: l   
        real :: esat
        real :: ws
        real :: w
    
        if (t < 235.) then 
            l = 2.83e6   ! latent heat of ice, doesn't change very much
        else
            l = l0 - (c - cpv) * (t - t0) ! latent heat of water
        endif
    
        esat = 6.11657*exp((l/461.51)*(1/273. - 1/t) ) ! saturation vapor pressure in mb
 
        ws = esat * 0.622 / (p - esat) ! saturation mixing ratio in kg/kg   
 
        w = rh / 100. * ws ! mixing ratio in kg/kg
    
        get_w = w * 1000. ! mixing ratio in g/kg
    
 
 
    end function get_w
 
 
  
end module global_model_grids