var/da/da_physics/da_tprh_to_q_lin.inc

   1 subroutine da_tprh_to_q_lin(grid)
   2
   3    !---------------------------------------------------------------------------
   4    ! Purpose: Convert T/pressure/rh to specific humidity increments.
   5    !
   6    ! Method: q~ = q (rh~/rh + qs~/qs)
   7    !---------------------------------------------------------------------------
   8
   9    implicit none
  10
  11    type (domain), intent(inout) :: grid
  12
  13    real :: qs_prime_over_qs(its:ite,jts:jte,kts:kte) ! qs~/qs.
  14
  15    if (trace_use) call da_trace_entry("da_tprh_to_q_lin")
  16
  17    !---------------------------------------------------------------------------
  18    ! [1.0] Calculate saturation specific humidity ratio qs~/qs:
  19    !---------------------------------------------------------------------------
  20
  21    call da_tp_to_qs_lin( grid, qs_prime_over_qs )
  22
  23    !---------------------------------------------------------------------------
  24    ! [2.0] Calculate specific humidity increment:
  25    !---------------------------------------------------------------------------
  26
  27    grid%xa % q(its:ite,jts:jte,kts:kte) = grid%xb % q(its:ite,jts:jte,kts:kte) * &
  28                                ( grid%xa % rh(its:ite,jts:jte,kts:kte) / &
  29                                  grid%xb % rh(its:ite,jts:jte,kts:kte) + &
  30                                  qs_prime_over_qs(its:ite,jts:jte,kts:kte) )
  31
  32    if (trace_use) call da_trace_exit("da_tprh_to_q_lin")
  33
  34 end subroutine da_tprh_to_q_lin
  35
  36