get_npp.h File Reference

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Functions
float	npp_vgpm (float chl, float irr, float sst, float dayL)
float	npp_eppley (float chl, float irr, float sst, float dayL)
double	npp_cbpm2 (double chl, double bbp, double irr, double k490, double mld, double zno3, double daylength)
float	get_zno3 (float lon, float lat, int day)
double	Kd490_obpg (l2str *l2rec, float *kd)
void	get_par_clim (float *parin, float *lat, float *lon, int nlat, int nlon, float *latp, float *lonp, int32_t npix, float *par)

Function Documentation

get_par_clim()

void get_par_clim	(	float *	parin,
		float *	lat,
		float *	lon,
		int	nlat,
		int	nlon,
		float *	latp,
		float *	lonp,
		int32_t	npix,
		float *	par
	)

Definition at line 336 of file get_npp.c.

get_zno3()

float get_zno3	(	float	lon,
		float	lat,
		int	day
	)

Definition at line 20 of file get_zno3.c.

Kd490_obpg()

double Kd490_obpg	(	l2str *	l2rec,
		float *	kd
	)

npp_cbpm2()

double npp_cbpm2	(	double	chl,
		double	bbp,
		double	irr,
		double	k490,
		double	mld,
		double	zno3,
		double	daylength
	)

!Description: opp_cbpm2 - computes daily primary productivity using a chl:Carbon ratio. This is a spectrally resolved version of the cbpm, using nine separate wavelengths. It is also depth resolved, integrating the effects from the surface down to a fixed depth of 200 m.

The cbpm2 algorithm estimates productivity using chl (m-1), bbp (m-1), surface irradiance (Einsteins m-2 d-1), k490 (m-1), mld (m), zno3 (m) and day length (hours).

Net primary productivity is carbon * growth rate, where carbon is proportional to particulate backscatter

carbon = 13000 * (bbp - 0.00035)

and growth rate is a function of nutrient and temperature stress (f(nut,T) and photoacclimation (f(Ig))

growth rate (u) = umax * f(nut,T) * f(Ig)

where:

umax = 2

f(nut,T) = ((Chl/C)sat - y0) / ((Chl/C)max - y0)

f(Ig) = 1 - exp (-5 * Ig)

and:

(Chl/C)sat = ratio of satellite observed chl and carbon (carbon from bbp)

(Chl/C)max = 0.022 + (0.045-0.022) * exp (-3 * Ig)

Ig = median mixed layer light level
   = surface irradiance * exp (-k(lambda) * MLD/2)

The above items are analyzed for nine separate wavelengths, and is vertically resolved to a depth of 200 m.

For more details, please see the paper by Westberry, et al (2008)

!Input Parameters:

Parameters

[in]	chl	chlorophyll concentration
[in]	bbp	backscatter
[in]	irr	Photosynthetically available radiation in Einsteins per day per square meter
[in]	k490	absorbence at 490nm
[in]	mld	mixing layer depth in meters
[in]	zno3	depth of the nitrocline
[in]	daylength	length of the day in decimal hours.

!Output Parameters:

Parameters

[out]

Primary

productivity in milligrams Carbon per square meter per day

!Dependencies: function austinPetzold_1986 ( float lambda, float K490 )

given a reference k490 vlaue, determine k(lambda) for a specified lambda

ref: Austin, R. W., and T. J. Petzold (1986), Spectral dependence of the diffuse attenuation coefficient of light in ocean waters, Opt. Eng., 25, 473 – 479

!Revision History:

08-16-2010 first release version (Robert O'Malley) [original code written in matlab by T. Westberry]

01-05-2011 O'Malley add uMax trap on mu[m] correct z_eu determination

!References and Credits

Westberry, T. Behrenfeld, M.J., Siegel, D.A., and Boss, E.; 2008. Carbon-based primary productivity modeling with vertically resolved photoacclimation. Global Biogeochemical Cycles, Vol. 22, GB2024, doi:10.1029/2007GB003078

Definition at line 662 of file get_npp.c.

npp_eppley()

float npp_eppley	(	float	chl,
		float	irr,
		float	sst,
		float	dayL
	)

Definition at line 530 of file get_npp.c.

npp_vgpm()

float npp_vgpm	(	float	chl,
		float	irr,
		float	sst,
		float	dayL
	)

!C-----------------------------------------------------------------------—*\

!Description: opp_befa - computes daily primary productivity using the Behrenfeld-Falkowski (BeFa) algorithm. The BeFa algorithm estimates productivity using surface chl (mg m-3), surface irradiance (Einsteins m-2 d-1), sea surface temperature (C). Pb_opt is modelled as a polynomial function of SST.

!Input Parameters:

Parameters

[in]	chl	Chlorophyll_a surface concentration in milligrams chlorophyl per cubic meter
[in]	irr	Photosynthetically available radiation in Einsteins per day per square meter
[in]	sst	Sea surface temperature in degrees Centigrade
[in]	dayL	Length day in decimal hours.

!Output Parameters:

Parameters

[out]

Primary

productivity in milligrams Carbon per square meter per hour

!Revision History:

First programmed up by Monica Chen at Rutgers (1996)

Revised by K. Turpie at NASA (August 1997)

Maintained by Don Shea at NASA

Now maintained by Robert O'Malley at Oregon State University (April, 2005 - present)

Modified for inclusion in l2gen for OBPG by R. Healy at NASA (January 2015)

!References and Credits

Behrenfeld,M.J; Falkowski,P.G.; 1997. Photosynthetic Rates Derived from Satellite-Based Chlorophyll Concentration. Limnology and Oceanography, Volume 42, Number 1

!END---------------------------------------------------------------------—*\

Definition at line 420 of file get_npp.c.