vertical_coordinate_transformations.h File Reference

#include "fimex/mifi_constants.h"

Go to the source code of this file.

Functions
int	mifi_atmosphere_ln_pressure (size_t n, double p0, const double *lev, double *pressure)
int	mifi_atmosphere_sigma_pressure (size_t n, double ptop, double ps, const double *level, double *pressure)
int	mifi_atmosphere_pressure_sigma (size_t n, double ptop, double ps, const double *pressure, double *level)
int	mifi_atmosphere_hybrid_sigma_pressure (size_t n, double p0, double ps, const double *a, const double *b, double *pressure)
int	mifi_atmosphere_hybrid_sigma_ap_pressure (size_t n, double ps, const double *ap, const double *b, double *pressure)
int	mifi_barometric_pressure (size_t n, double P_b, const double *h, double T_b, double *pressure)
int	mifi_barometric_standard_pressure (size_t n, const double *h, double *pressure)
int	mifi_barometric_height (size_t n, double P_b, const double *p, double T_b, double *height)
int	mifi_barometric_standard_altitude (size_t n, const double *p, double *altitude)
float	mifi_virtual_temperature (float spec_humidity, float t)
float	mifi_relative_to_specific_humidity (float rh, float t, float p)
float	mifi_specific_to_relative_humidity (float sh, float t, float p)
float	mifi_dewpoint_to_relative_humidity (float dew, float t)
float	mifi_barometric_layer_thickness (float p_low_alti, float p_high_alti, float T)
int	mifi_ocean_s_g1_z (size_t n, double h, double h_c, double zeta, const double *s, const double *C, double *z)
int	mifi_ocean_s_g2_z (size_t n, double h, double h_c, double zeta, const double *s, const double *C, double *z)
int	mifi_omega_to_vertical_wind (size_t n, const double *omega, const double *p, const double *t, double *w)
int	mifi_vertical_wind_to_omega (size_t n, const double *w, const double *p, const double *t, double *omega)

Function Documentation

int mifi_atmosphere_hybrid_sigma_ap_pressure	(	size_t	n,
		double	ps,
		const double *	ap,
		const double *	b,
		double *	pressure
	)

convert a standard_name="atmosphere_hybrid_sigma_pressure_coordinate" to pressure using the formula p(k) = ap(k) + b(k)*ps

This is the same as mifi_atmosphere_hybrid_sigma_pressure(), but with the reference pressure and a joined already. Choice depends on the model, i.e. available input values.

Parameters

n	size of arrays ap, b and pressure
ps	surface pressure - usually varying in time,x,y
ap	pressure level values
b	dimensionless level values
pressure	output values in the same unit as p0 and ps and at the same place as ps

Returns

MIFI_OK on success or MIFI_ERROR on failure

int mifi_atmosphere_hybrid_sigma_pressure	(	size_t	n,
		double	p0,
		double	ps,
		const double *	a,
		const double *	b,
		double *	pressure
	)

convert a standard_name="atmosphere_hybrid_sigma_pressure_coordinate" to pressure using the formula p(k) = a(k)*p0 + b(k)*ps

Parameters

n	size of arrays a, b and pressure
p0	reference pressure
ps	surface pressure - usually varying in time,x,y
a	dimensionless level values
b	dimensionless level values
pressure	output values in the same unit as p0 and ps and at the same place as ps

Returns

MIFI_OK on success or MIFI_ERROR on failure

int mifi_atmosphere_ln_pressure	(	size_t	n,
		double	p0,
		const double *	lev,
		double *	pressure
	)

convert a standard_name="atmosphere_ln_pressure_coordinate" to pressure using the formula p(k) = p0 * exp(-lev(k))

Parameters

n	size of arrays lev and pressure
p0	base pressure
lev	level values
pressure	output values in the same unit as p0

Returns

MIFI_OK on success or MIFI_ERROR on failure

int mifi_atmosphere_pressure_sigma	(	size_t	n,
		double	ptop,
		double	ps,
		const double *	pressure,
		double *	level
	)

convert a pressure to standard_name="atmosphere_sigma_coordinate" using the formula p(k) = ptop + sigma(k)*(ps-ptop) -> sigma(k) = (p(k) - ptop)/(ps-ptop)

Parameters

n	size of arrays sigma and pressure
ptop	pressure on model top layer (constant for a model)
ps	surface pressure - usually varying in time,x,y
pressure	pressure level values in the same unit as ptop and ps
level	sigma output values at the same place as ps

Returns

MIFI_OK on success or MIFI_ERROR on failure

int mifi_atmosphere_sigma_pressure	(	size_t	n,
		double	ptop,
		double	ps,
		const double *	level,
		double *	pressure
	)

convert a standard_name="atmosphere_sigma_coordinate" to pressure using the formula p(k) = ptop + sigma(k)*(ps-ptop)

Parameters

n	size of arrays sigma and pressure
ptop	pressure on model top layer (constant for a model)
ps	surface pressure - usually varying in time,x,y
level	sigma level values
pressure	output values in the same unit as ptop and ps and at the same place as ps

Returns

MIFI_OK on success or MIFI_ERROR on failure

int mifi_barometric_height	(	size_t	n,
		double	P_b,
		const double *	p,
		double	T_b,
		double *	height
	)

convert pressure to height using the inverse formula http://en.wikipedia.org/wiki/Barometric_formula

h(k) = -R*T_b/g*M * log(p(k)/P_b);

with P_b and T_b pressure and temperature at the layer b (i.e. surface)

g = 9.80665 m/s2 M = Molar mass of Earth's air (0.0289644 kg/mol) R = Universal gas constant (8.31432 N·m /(mol·K) )

Parameters

n	size of array h and pressure
P_b	pressure at base-layer (i.e. surface, or means-sea-level) - usually varying in time,x,y
p	pressure at level
T_b	temperature at base layer in K - usually varying in time,x,y
height	output values, height above base_layer in m

Warning

This function has not been tested against possibly existing implementations

float mifi_barometric_layer_thickness	(	float	p_low_alti,
		float	p_high_alti,
		float	T
	)

convert pressure difference to layer thickness using the hyspometric equation http://en.wikipedia.org/wiki/Hypsometric_equation

Parameters

p_low_alti	pressure at lower altitude in hPa
p_high_alti	pressure at higher altitude in hPa
T	temperature in K

Returns

layer thickness in m

int mifi_barometric_pressure	(	size_t	n,
		double	P_b,
		const double *	h,
		double	T_b,
		double *	pressure
	)

convert height above base-layer (usually altitude, i.e. height above MSL) to pressure using the formula http://en.wikipedia.org/wiki/Barometric_formula

P(h) = P_b exp[ -gM/R * h/T_b ]

with P_b and T_b pressure and temperature at the layer b (i.e. surface) and h_b the height above the layer b

g = 9.80665 m/s2 M = Molar mass of Earth's air (0.0289644 kg/mol) R = Universal gas constant (8.31432 N·m /(mol·K) )

Parameters

n	size of array h and pressure
P_b	pressure at base-layer (e.g. means-sea-level) - usually varying in time,x,y
h	height in m above base-layer
T_b	temperature at base layer in K - usually varying in time,x,y
pressure	output values in the same unit as p_b and at the same place as ps

Warning

This function has not been tested against possibly existing implementations

int mifi_barometric_standard_altitude	(	size_t	n,
		const double *	p,
		double *	altitude
	)

convert pressure to height using the formula http://en.wikipedia.org/wiki/Barometric_formula and using the international standard atmosphere http://en.wikimedia.org/wiki/International_Standard_Atmosphere

Parameters

altitude

output values, i.e. height above mean sea level in m

int mifi_barometric_standard_pressure	(	size_t	n,
		const double *	h,
		double *	pressure
	)

convert altitude to pressure using the formula http://en.wikipedia.org/wiki/Barometric_formula and using the international standard atmosphere http://en.wikipedia.org/wiki/International_Standard_Atmosphere

float mifi_dewpoint_to_relative_humidity	(	float	dew,
		float	t
	)

Calculate relative humidity from dewpoint temperature and temperature. Derived from Bolton, 1980: http://www.eol.ucar.edu/projects/ceop/dm/documents/refdata_report/eqns.html

Parameters

dew	dewpoint temperature in K
t	temperature in K

Returns

relative humidity in %

int mifi_ocean_s_g1_z	(	size_t	n,
		double	h,
		double	h_c,
		double	zeta,
		const double *	s,
		const double *	C,
		double *	z
	)

convert a standard_name="ocean_s_coordinate_g1" to z using the formula z(k) = h_c*sigma(k) + C(k)*(h - h_c) + zeta*(1+(h_c*sigma(k)+C(k)*(h-h_c)/h))

Parameters

n	size of arrays s and C pressure
h	unperturbed water column thickness - varying in x,y (might be varying in time for sediment applications)
h_c	critical depth, usually min(h(x,y))
zeta	time-varying free surface - varying in time,x,y
s	s(k) dimensionless s coordinate
C	zeta(k) streching function
z	output values in the same unit as h and h_c and at the same place as h

Returns

MIFI_OK on success or MIFI_ERROR on failure

See also

https://www.myroms.org/wiki/index.php?title=Vertical_S-coordinate

int mifi_ocean_s_g2_z	(	size_t	n,
		double	h,
		double	h_c,
		double	zeta,
		const double *	s,
		const double *	C,
		double *	z
	)

convert a standard_name="ocean_s_coordinate_g1" to z using the formula z(k) = zeta + (zeta +h)*(h_c*sigma + h*C(k))/(h_c+h)

Parameters

n	size of arrays s and C pressure
h	unperturbed water column thickness - varying in x,y (might be varying in time for sediment applications)
h_c	critical depth, usually min(h(x,y))
zeta	time-varying free surface - varying in time,x,y
s	s(k) dimensionless s coordinate
C	zeta(k) streching function
z	output values in the same unit as h and h_c and at the same place as h

Returns

MIFI_OK on success or MIFI_ERROR on failure

See also

https://www.myroms.org/wiki/index.php?title=Vertical_S-coordinate

int mifi_omega_to_vertical_wind	(	size_t	n,
		const double *	omega,
		const double *	p,
		const double *	t,
		double *	w
	)

convert the vertical pressure change omega to vertical wind-speed using omega = - rho * g * w

Parameters

n	size of the array omega, p, t, w
omega	vertical flow in Pa/s
p	pressure in Pa
t	temperature in K
w	output-array for vertical wind speed in m/s

Returns

MIFI_OK status

float mifi_relative_to_specific_humidity	(	float	rh,
		float	t,
		float	p
	)

Calculate specific humidity from relative humidity and temperature. Derived from HIRLAM version 2.6.0, by G. Cats

Parameters

rh	relative humidity in %
temperature	in K
p	pressure in hPa

Returns

specific humidity in kg/kg

float mifi_specific_to_relative_humidity	(	float	sh,
		float	t,
		float	p
	)

Calculate specific humidity from relative humidity and temperature. Derived from HIRLAM version 2.6.0, by G. Cats

Parameters

sh	specific humidity in kg/kg
temperature	in K
p	pressure in hPa

Returns

relative humidity in %

int mifi_vertical_wind_to_omega	(	size_t	n,
		const double *	w,
		const double *	p,
		const double *	t,
		double *	omega
	)

convert the vertical wind-speed in m/s to vertical pressure change omega using omega = - rho * g * w

Parameters

n	size of the array omega, p, t, w
w	vertical wind speed in m/s
p	pressure in Pa
t	temperature in K
omega	output-array of vertical flow in Pa/s

Returns

MIFI_OK status

float mifi_virtual_temperature	(	float	spec_humidity,
		float	t
	)

calculate virtual temperature from specific humidity and temperature

Parameters

spec_humidity	specific humidity in kg/kg
temperature	in K

Returns

virtual temperature in K