nox_pulse.c File Reference

#include <stdio.h>
#include <stdlib.h>
#include <math.h>

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Macros
#define	PPTDAYS   15
#define	PLDAYS   2
#define	PMDAYS   6
#define	PHDAYS   13

Functions
double	max3 (double a, double b, double c)
double	nox_pulse (double *ppt, double *snow)

Macro Definition Documentation

#define PHDAYS   13

#define PLDAYS   2

#define PMDAYS   6

#define PPTDAYS   15

Function Documentation

double max3	(	double	a,
		double	b,
		double	c
	)

    {
      double m;
   
      if (a > b) 
        m = a;
      else
        m = b;

      if (c > m)
        m = c;

      return(m);
    }

double nox_pulse	(	double *	ppt,
		double *	snow
	)

    {
      static double cumppt[PPTDAYS] = {0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,
                                      0.0,0.0,0.0,0.0,0.0,0.0,0.0};
      static double pl[PLDAYS] = {1.0,1.0};
      static double pm[PMDAYS] = {1.0,1.0,1.0,1.0,1.0,1.0};
      static double ph[PHDAYS] = {1.0,1.0,1.0,1.0,1.0,1.0,1.0,1.0,1.0,
                                 1.0,1.0,1.0,1.0};
      static double mtplr[PHDAYS] = {1.0,1.0,1.0,1.0,1.0,1.0,1.0,1.0,
                                    1.0,1.0,1.0,1.0,1.0};
      static int npl=0, npm=0, nph=0, nppt=0, mptr=0;
      static int pflag=0;
      double sumppt;
      double retval;
      int ii, indx;

      sumppt = 0.0;
      cumppt[nppt] = *ppt;
      for (ii=1; ii<PPTDAYS; ii++) {
        indx = (nppt+ii) % PPTDAYS;
        sumppt += cumppt[indx];
      } 

      /* Comparisons with data showed NO emissions to be about twice of */
      /* what they should be, reduce the pulse multipliers, cak - 09/24/03 */
      if (*snow) { 
        mtplr[mptr] = 0.0;
      } else if ((sumppt <= 1.0) && (*ppt > 0.1)) {
        /* initiate new pulse */
        if (*ppt < 0.5) {
          for (ii=0; ii<PLDAYS; ii++) {
            indx = (npl+ii) % PLDAYS;
            pl[indx] = 2.8 * exp(-0.805 * (ii+1));
          }
          pflag = 2;
        } else if ((*ppt >= 0.5) && (*ppt <= 1.5)) {
          for (ii=0; ii<PMDAYS; ii++) {
            indx = (npm+ii) % PMDAYS;
            pm[indx] = 3.67 * exp(-0.384 * (ii+1));
          }
          pflag = 6;
        } else {
          for (ii=0; ii<PHDAYS; ii++) {
            indx = (nph+ii) % PHDAYS;
            ph[indx] = 4.615 * exp(-0.208 * (ii+1));
          }
          pflag = 13;
        }

        mtplr[mptr] = max3(pl[npl],pm[npm],ph[nph]);
        pflag--;
      } else if (pflag > 0) {
        mtplr[mptr] = max3(pl[npl],pm[npm],ph[nph]);
        pflag--;
      } else {
        mtplr[mptr] = 1.0;
      }

      retval = mtplr[mptr];
      pl[npl] = 1.0;
      pm[npm] = 1.0;
      ph[nph] = 1.0;

      /* increment pointers in circular arrays */
      npl = (npl+1) % PLDAYS;
      npm = (npm+1) % PMDAYS;
      nph = (nph+1) % PHDAYS;
      nppt = (nppt+1) % PPTDAYS;
      mptr = (mptr+1) % PHDAYS;

      return(retval);
    }