da_get_q_error.inc

1 subroutine da_get_q_error( p, t, q, t_error, rh_error, q_error)
2 
3    !-----------------------------------------------------------------------
4    ! Purpose: TBD
5    !-----------------------------------------------------------------------
6 
7    implicit none
8 
9    real, intent(in)  :: p        ! Observed pressure.
10    real, intent(in)  :: t        ! Observed temperature.
11    real, intent(in)  :: q        ! Observed specific humidity.
12    real, intent(in)  :: t_error  ! Temperature observation error.
13    real, intent(in)  :: rh_error ! RH observation error.
14    real, intent(out) :: q_error  ! q observation error.
15 
16    real :: es    ! Saturation vapor pressure.
17    real :: qs    ! Saturation specific humidity.
18    real :: rh    ! Relative humidity.
19 
20    real :: f_qv_from_rh
21    external f_qv_from_rh
22 
23    if (trace_use_frequent) call da_trace_entry("da_get_q_error")
24 
25    if (ABS(p - missing_r) > 1.0 .AND. ABS(t - missing_r) > 1.0 .AND. ABS(q - missing_r) > 1) then
26       ! Calculate rh:
27       call da_tp_to_qs( t, p, es, qs)
28 
29       rh = 100.0 * q / qs
30       if (rh > 100.0) rh = 100.0
31 
32       ! Get observation error for qv. Is this right?
33       q_error = f_qv_from_rh( rh_error, t_error, rh, t, p)
34    else
35       q_error = missing_r
36    end if
37 
38    if (q_error == 0.0) q_error = missing_r
39 
40    if (trace_use_frequent) call da_trace_exit("da_get_q_error")
41 
42 end subroutine da_get_q_error
43 
44