MODULE obs_def_dew_point_mod¶

Overview¶

Provides a subroutine to calculate the dew point temperature from model temperature, specific humidity, and pressure.

Revision 2801 implements a more robust method (based on Bolton’s Approximation) for calculating dew point. This has been further revised to avoid a numerical instability that could lead to failed forward operators for dewpoints almost exactly 0 C.

Other modules used¶

types_mod
utilities_mod
location_mod (most likely threed_sphere)
assim_model_mod
obs_kind_mod

Public interfaces¶

use obs_def_dew_point_mod, only :

get_expected_dew_point

A note about documentation style. Optional arguments are enclosed in brackets [like this].

call get_expected_dew_point(state_vector, location, key, td, istatus)

real(r8),            intent(in)  :: state_vector
type(location_type), intent(in)  :: location
integer,             intent(in)  :: key
real(r8),            intent(out) :: td
integer,             intent(out) :: istatus

Calculates the dew point temperature (Kelvin).

`state_vector`	A one dimensional representation of the model state vector
`location`	Location for this obs
`key`	Controls whether upper levels (key = 1) or 2-meter (key = 2) is required.
`td`	The returned dew point temperature value
`istatus`	Returned integer describing problems with applying forward operator

Files¶

NONE

References¶

Bolton, David, 1980: The Computation of Equivalent Potential Temperature. Monthly Weather Review, 108, 1046-1053.