/*
bgc_constants.h
Holds macro definitions for constants used in bgc()

*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*
Biome-BGC version 4.1.2
Copyright 2002, Peter E. Thornton

Revisions from version 4.1.1:
Moved the heterotrophic respiration fractions and base decomposition rates 
out of the science subroutines and into the constants file so that it is
easier to make sure modifications are propagated correctly.
*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*
*/

/* atmospheric constants */
/* from the definition of the standard atmosphere, as established
by the International Civil Aviation Organization, and referenced in:

Iribane, J.V., and W.L. Godson, 1981. Atmospheric Thermodynamics. 2nd 
	Edition. D. Reidel Publishing Company, Dordrecht, The Netherlands.
	(pp 10,167-168,245)
*/
#define G_STD    9.80665         /* (m/s2) standard gravitational accel. */ 
#define P_STD    101325.0        /* (Pa) standard pressure at 0.0 m elevation */
#define T_STD    288.15          /* (K) standard temp at 0.0 m elevation  */ 
#define MA       28.9644e-3      /* (kg/mol) molecular weight of air */
#define MW       18.0148e-3      /* (kg/mol) molecular weight of water */
#define CP       1010.0          /* (J/kg K) specific heat of air */
#define LR_STD   0.0065          /* (-K/m) standard temperature lapse rate */
#define R        8.3143          /* (m3 Pa/ mol K) gas law constant */
#define SBC      5.67e-8         /* (W/(m2 K4)) Stefan-Boltzmann constant */
#define EPS      0.6219          /* (MW/MA) unitless ratio of molec weights */

/* ecosystem constants */
#define RAD2PAR     0.45     /* (DIM) ratio PAR / SWtotal  */
#define EPAR        4.55     /* (umol/J) PAR photon energy ratio */  
#define SOIL1_CN    12.0     /* C:N for fast microbial recycling pool */
#define SOIL2_CN    12.0     /* C:N for slow microbial recycling pool */
#define SOIL3_CN    10.0     /* C:N for recalcitrant SOM pool (humus) */
#define SOIL4_CN    10.0     /* C:N for recalcitrant SOM pool (humus) */
#define GRPERC      0.3      /* (DIM) growth resp per unit of C grown */
#define GRPNOW      1.0      /* (DIM) proportion of storage growth resp at fixation */
#define PPFD50      75.0     /* (umol/m2/s) PPFD for 1/2 stomatal closure */
#define DENITRIF_PROPORTION  0.01  /* fraction of mineralization to volatile */
#define MOBILEN_PROPORTION   0.1   /* fraction mineral N avail for leaching */

/* use this block of constants to include the dynamics for slowest soil pool (s4) */
/* respiration fractions for fluxes between compartments (unitless) */ 
#define	RFL1S1		0.39	/* transfer from litter 1 to soil 1 */
#define	RFL2S2		0.55	/* transfer from litter 2 to soil 2 */
#define	RFL4S3		0.29	/* transfer from litter 4 to soil 3 */
#define	RFS1S2		0.28	/* transfer from soil 1 to soil 2 */
#define	RFS2S3		0.46    /* transfer from soil 2 to soil 3 */
#define	RFS3S4		0.55	/* transfer from soil 3 to soil 4 */
/* base decomposition rate constants (1/day) */ 
#define KL1_BASE	0.7		/* labile litter pool */
#define KL2_BASE	0.07	/* cellulose litter pool */
#define KL4_BASE	0.014	/* lignin litter pool */
#define KS1_BASE	0.07	/* fast microbial recycling pool */
#define KS2_BASE	0.014	/* medium microbial recycling pool */
#define KS3_BASE	0.0014	/* slow microbial recycling pool */
#define KS4_BASE	0.0001	/* recalcitrant SOM (humus) pool */
#define KFRAG_BASE	0.001	/* physical fragmentation of coarse woody debris */

/* use this block of constants to exclude the dynamics for slowest soil pool (s4) */
/* respiration fractions for fluxes between compartments (unitless) */ 
/*#define	RFL1S1	0.39*/	/* transfer from litter 1 to soil 1 */
/*#define	RFL2S2	0.55*/	/* transfer from litter 2 to soil 2 */
/*#define	RFL4S3	0.29*/	/* transfer from litter 4 to soil 3 */
/*#define	RFS1S2	0.28*/	/* transfer from soil 1 to soil 2 */
/*#define	RFS2S3	0.46*/  /* transfer from soil 2 to soil 3 */
/*#define	RFS3S4	1.00*/	/* transfer from soil 3 to soil 4 */
/* base decomposition rate constants (1/day) */ 
/*#define KL1_BASE	0.7	*/	/* labile litter pool */
/*#define KL2_BASE	0.07*/	/* cellulose litter pool */
/*#define KL4_BASE	0.014*/	/* lignin litter pool */
/*#define KS1_BASE	0.07*/	/* fast microbial recycling pool */
/*#define KS2_BASE	0.014*/	/* medium microbial recycling pool */
/*#define KS3_BASE	0.0005*/	/* slow microbial recycling pool */
/*#define KS4_BASE	0.0000*/	/* recalcitrant SOM (humus) pool */

/* precision control */
/* This constant determines the lower limit of state variables before they
are set to 0.0 to control rounding and overflow errors */
#define CRIT_PREC 1e-20

/* spinup control */
/* maximum allowable trend in slow soil carbon at steady-state (kgC/m2/yr) */
#define SPINUP_TOLERANCE 0.0005

/* output control constants */
#define NMAP 700