grib2_util Module Reference

Utilities for use when reading grib2 data. More...

Functions/Subroutines
subroutine, public	convert_omega (omega, p, t, q, clb, cub)
	Convert omega to vertical velocity. More...
elemental real function, public	fpvsnew (t)
	Compute saturation vapor pressure. More...
subroutine, public	rh2spfh (rh_sphum, p, t)
	Convert relative humidity to specific humidity. More...
subroutine, public	rh2spfh_gfs (rh_sphum, p, t)
	Convert relative humidity to specific humidity (GFS formula) Calculation of saturation water vapor pressure is based on GFS function fvpsnew (Phillips 1982). More...

Detailed Description

Utilities for use when reading grib2 data.

This module contains routines to:

• convert from RH to specific humidity
• convert from omega to dzdt.

George Gayno NCEP/EMC

Function/Subroutine Documentation

convert_omega()

subroutine, public grib2_util::convert_omega	(	real(esmf_kind_r8), dimension(:,:,:), pointer	omega,
		real(esmf_kind_r8), dimension(:,:,:), pointer	p,
		real(esmf_kind_r8), dimension(:,:,:), pointer	t,
		real(esmf_kind_r8), dimension(:,:,:), pointer	q,
		integer, dimension(3)	clb,
		integer, dimension(3)	cub
	)

Convert omega to vertical velocity.

Parameters

[in,out]	omega	on input, vertical velocity on output
[in]	p	pressure
[in]	t	temperature
[in]	q	specific humidity
[in]	clb	lower bounds of indices processed by this mpi task
[in]	cub	upper bounds of indices processed by this mpi task

Author

Larissa Reames

Jeff Beck

Definition at line 218 of file grib2_util.F90.

Referenced by atm_input_data::read_input_atm_grib2_file().

fpvsnew()

elemental real function, public grib2_util::fpvsnew

(

real(esmf_kind_r8), intent(in)

t

)

Compute saturation vapor pressure.

Parameters

[in]

t

temperature in Kelvin

Returns

fpvsnew Saturation vapor pressure

Author

N Phillips w/NMC2X2

Date

30 dec 82

Definition at line 136 of file grib2_util.F90.

Referenced by rh2spfh_gfs().

rh2spfh()

subroutine, public grib2_util::rh2spfh	(	real(esmf_kind_r4), dimension(i_input,j_input), intent(inout)	rh_sphum,
		real(esmf_kind_r8), intent(in)	p,
		real(esmf_kind_r8), dimension(i_input,j_input), intent(in)	t
	)

Convert relative humidity to specific humidity.

Calculation of saturation water vapor pressure is based on Brock and Richardson 2001 (Meterological Measurement Systems, p. 86, equation 5.1)

Parameters

[in,out]	rh_sphum	rel humidity (%) on input. spec hum (kg/kg) on output.
[in]	p	pressure in Pa
[in]	t	temperature

Author

Larissa Reames

Jeff Beck

Definition at line 38 of file grib2_util.F90.

Referenced by atm_input_data::read_input_atm_grib2_file().

rh2spfh_gfs()

subroutine, public grib2_util::rh2spfh_gfs	(	real(esmf_kind_r4), dimension(i_input,j_input), intent(inout)	rh_sphum,
		real(esmf_kind_r8), intent(in)	p,
		real(esmf_kind_r8), dimension(i_input,j_input), intent(in)	t
	)

Convert relative humidity to specific humidity (GFS formula) Calculation of saturation water vapor pressure is based on GFS function fvpsnew (Phillips 1982).

The model does account for the variation of the latent heat of condensation with temperature. A linear interpolation is done between values in a calculated lookup table. Ice and water are considered separately. This option provides a consistent conversion for GFS grib2 data to be ingested.

Parameters

[in,out]	rh_sphum	rel humidity on input. spec hum on output.
[in]	p	pressure in Pa
[in]	t	temperature

Author

Jili Dong NCEP/EMC

Definition at line 81 of file grib2_util.F90.

References fpvsnew(), model_grid::i_input, and model_grid::j_input.

Referenced by atm_input_data::read_input_atm_grib2_file().