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root/radiance/ray/src/gen/gendaylit.c
Revision: 2.14
Committed: Fri Sep 6 16:54:06 2013 UTC (10 years, 7 months ago) by greg
Content type: text/plain
Branch: MAIN
Changes since 2.13: +181 -155 lines
Log Message:
Latest updates and bug fixesx from Wendelin

File Contents

# User Rev Content
1 greg 2.9 /* Copyright (c) 1994,2006 *Fraunhofer Institut for Solar Energy Systems
2     * Heidenhofstr. 2, D-79110 Freiburg, Germany
3 greg 2.1 * *Agence de l'Environnement et de la Maitrise de l'Energie
4     * Centre de Valbonne, 500 route des Lucioles, 06565 Sophia Antipolis Cedex, France
5     * *BOUYGUES
6     * 1 Avenue Eugene Freyssinet, Saint-Quentin-Yvelines, France
7     */
8    
9     #include <stdio.h>
10     #include <string.h>
11     #include <math.h>
12     #include <stdlib.h>
13    
14     #include "color.h"
15 greg 2.12 #include "sun.h"
16 greg 2.1 #include "paths.h"
17    
18 greg 2.9 #define DOT(v1,v2) (v1[0]*v2[0]+v1[1]*v2[1]+v1[2]*v2[2])
19 greg 2.14 #define _USE_MATH_DEFINES
20 greg 2.1
21     double normsc();
22    
23 greg 2.14 /*static char *rcsid="$Header: /tmp_mnt/nfs/koll7/users/koll/jean/program/radiance/RAD/RCS/gendaylit.c,v 1.13 94/05/17 19:21:01 jean Exp Locker: jean $";*/
24 greg 2.9
25     float coeff_perez[] = {
26 greg 2.12 1.3525,-0.2576,-0.2690,-1.4366,-0.7670,0.0007,1.2734,-0.1233,2.8000,0.6004,1.2375,1.000,1.8734,0.6297,
27     0.9738,0.2809,0.0356,-0.1246,-0.5718,0.9938,-1.2219,-0.7730,1.4148,1.1016,-0.2054,0.0367,-3.9128,0.9156,
28     6.9750,0.1774,6.4477,-0.1239,-1.5798,-0.5081,-1.7812,0.1080,0.2624,0.0672,-0.2190,-0.4285,-1.1000,-0.2515,
29     0.8952,0.0156,0.2782,-0.1812,-4.5000,1.1766,24.7219,-13.0812,-37.7000,34.8438,-5.0000,1.5218,3.9229,
30     -2.6204,-0.0156,0.1597,0.4199,-0.5562,-0.5484,-0.6654,-0.2672,0.7117,0.7234,-0.6219,-5.6812,2.6297,
31     33.3389,-18.3000,-62.2500,52.0781,-3.5000,0.0016,1.1477,0.1062,0.4659,-0.3296,-0.0876,-0.0329,-0.6000,
32     -0.3566,-2.5000,2.3250,0.2937,0.0496,-5.6812,1.8415,21.0000,-4.7656,-21.5906,7.2492,-3.5000,-0.1554,
33     1.4062,0.3988,0.0032,0.0766,-0.0656,-0.1294,-1.0156,-0.3670,1.0078,1.4051,0.2875,-0.5328,-3.8500,3.3750,
34     14.0000,-0.9999,-7.1406,7.5469,-3.4000,-0.1078,-1.0750,1.5702,-0.0672,0.4016,0.3017,-0.4844,-1.0000,
35     0.0211,0.5025,-0.5119,-0.3000,0.1922,0.7023,-1.6317,19.0000,-5.0000,1.2438,-1.9094,-4.0000,0.0250,0.3844,
36     0.2656,1.0468,-0.3788,-2.4517,1.4656,-1.0500,0.0289,0.4260,0.3590,-0.3250,0.1156,0.7781,0.0025,31.0625,
37     -14.5000,-46.1148,55.3750,-7.2312,0.4050,13.3500,0.6234,1.5000,-0.6426,1.8564,0.5636};
38    
39    
40     float defangle_theta[] = {
41     84, 84, 84, 84, 84, 84, 84, 84, 84, 84, 84, 84, 84, 84, 84, 84, 84, 84, 84, 84, 84, 84, 84, 84, 84, 84,
42     84, 84, 84, 84, 72, 72, 72, 72, 72, 72, 72, 72, 72, 72, 72, 72, 72, 72, 72, 72, 72, 72, 72, 72, 72, 72,
43     72, 72, 72, 72, 72, 72, 72, 72, 60, 60, 60, 60, 60, 60, 60, 60, 60, 60, 60, 60, 60, 60, 60, 60, 60, 60,
44     60, 60, 60, 60, 60, 60, 48, 48, 48, 48, 48, 48, 48, 48, 48, 48, 48, 48, 48, 48, 48, 48, 48, 48, 48, 48,
45     48, 48, 48, 48, 36, 36, 36, 36, 36, 36, 36, 36, 36, 36, 36, 36, 36, 36, 36, 36, 36, 36, 24, 24, 24, 24,
46     24, 24, 24, 24, 24, 24, 24, 24, 12, 12, 12, 12, 12, 12, 0};
47    
48     float defangle_phi[] = {
49     0, 12, 24, 36, 48, 60, 72, 84, 96, 108, 120, 132, 144, 156, 168, 180, 192, 204, 216, 228, 240, 252, 264,
50     276, 288, 300, 312, 324, 336, 348, 0, 12, 24, 36, 48, 60, 72, 84, 96, 108, 120, 132, 144, 156, 168, 180,
51     192, 204, 216, 228, 240, 252, 264, 276, 288, 300, 312, 324, 336, 348, 0, 15, 30, 45, 60, 75, 90, 105,
52     120, 135, 150, 165, 180, 195, 210, 225, 240, 255, 270, 285, 300, 315, 330, 345, 0, 15, 30, 45, 60, 75,
53     90, 105, 120, 135, 150, 165, 180, 195, 210, 225, 240, 255, 270, 285, 300, 315, 330, 345, 0, 20, 40, 60,
54     80, 100, 120, 140, 160, 180, 200, 220, 240, 260, 280, 300, 320, 340, 0, 30, 60, 90, 120, 150, 180, 210,
55     240, 270, 300, 330, 0, 60, 120, 180, 240, 300, 0};
56 greg 2.1
57    
58    
59 greg 2.14 /* Perez sky parametrization: epsilon and delta calculations from the direct and diffuse irradiances */
60 greg 2.1 double sky_brightness();
61     double sky_clearness();
62    
63     /* calculation of the direct and diffuse components from the Perez parametrization */
64 greg 2.9 double diffuse_irradiance_from_sky_brightness();
65 greg 2.1 double direct_irradiance_from_sky_clearness();
66    
67 greg 2.12 /* Perez global horizontal, diffuse horizontal and direct normal luminous efficacy models : */
68     /* input w(cm)=2cm, solar zenith angle(degrees); output efficacy(lm/W) */
69 greg 2.1
70     double glob_h_effi_PEREZ();
71     double glob_h_diffuse_effi_PEREZ();
72     double direct_n_effi_PEREZ();
73 greg 2.12
74 greg 2.1 /*likelihood check of the epsilon, delta, direct and diffuse components*/
75     void check_parametrization();
76     void check_irradiances();
77     void check_illuminances();
78     void illu_to_irra_index();
79 greg 2.9 void print_error_sky();
80 greg 2.1
81 greg 2.12 double calc_rel_lum_perez(double dzeta,double gamma,double Z,double epsilon,double Delta,float coeff_perez[]);
82 greg 2.9 void coeff_lum_perez(double Z, double epsilon, double Delta, float coeff_perez[]);
83 greg 2.1 double radians(double degres);
84     double degres(double radians);
85     void theta_phi_to_dzeta_gamma(double theta,double phi,double *dzeta,double *gamma, double Z);
86     double integ_lv(float *lv,float *theta);
87    
88 greg 2.9 void printdefaults();
89 greg 2.12 void check_sun_position();
90 greg 2.9 void computesky();
91     void printhead(int ac, char** av);
92 greg 2.14 void usage_error(char* msg);
93 greg 2.9 void printsky();
94 greg 2.1
95 greg 2.9 FILE * frlibopen(char* fname);
96 greg 2.1
97     /* astronomy and geometry*/
98     double get_eccentricity();
99     double air_mass();
100    
101 greg 2.14 double solar_sunset(int month, int day);
102     double solar_sunrise(int month, int day);
103 greg 2.12 double stadj();
104     int jdate(int month, int day);
105    
106 greg 2.1
107     /* sun calculation constants */
108 greg 2.12 extern double s_latitude;
109     extern double s_longitude;
110     extern double s_meridian;
111 greg 2.1
112     const double AU = 149597890E3;
113     const double solar_constant_e = 1367; /* solar constant W/m^2 */
114 greg 2.14 const double solar_constant_l = 127500; /* solar constant lux */
115 greg 2.1
116     const double half_sun_angle = 0.2665;
117     const double half_direct_angle = 2.85;
118    
119 greg 2.14 const double skyclearinf = 1.0; /* limitations for the variation of the Perez parameters */
120     const double skyclearsup = 12.01;
121 greg 2.1 const double skybriginf = 0.01;
122     const double skybrigsup = 0.6;
123    
124    
125    
126     /* required values */
127     int month, day; /* date */
128     double hour; /* time */
129     int tsolar; /* 0=standard, 1=solar */
130     double altitude, azimuth; /* or solar angles */
131    
132    
133    
134     /* definition of the sky conditions through the Perez parametrization */
135 greg 2.9 double skyclearness = 0;
136     double skybrightness = 0;
137 greg 2.12 double solarradiance;
138     double diffuseilluminance, directilluminance, diffuseirradiance, directirradiance, globalirradiance;
139     double sunzenith, daynumber, atm_preci_water=2;
140 greg 2.1
141 greg 2.12 /*double sunaltitude_border = 0;*/
142 greg 2.9 double diffnormalization = 0;
143 greg 2.12 double dirnormalization = 0;
144 greg 2.1 double *c_perez;
145    
146 greg 2.12 int output=0; /* define the unit of the output (sky luminance or radiance): */
147     /* visible watt=0, solar watt=1, lumen=2 */
148     int input=0; /* define the input for the calulation */
149 greg 2.1
150 greg 2.9 int suppress_warnings=0;
151    
152 greg 2.1 /* default values */
153 greg 2.12 int cloudy = 0; /* 1=standard, 2=uniform */
154     int dosun = 1;
155 greg 2.1 double zenithbr = -1.0;
156     double betaturbidity = 0.1;
157     double gprefl = 0.2;
158     int S_INTER=0;
159    
160     /* computed values */
161     double sundir[3];
162 greg 2.9 double groundbr = 0;
163 greg 2.1 double F2;
164     double solarbr = 0.0;
165     int u_solar = 0; /* -1=irradiance, 1=radiance */
166 greg 2.12 float timeinterval = 0;
167    
168     char *progname;
169     char errmsg[128];
170    
171 greg 2.14 double st;
172 greg 2.1
173    
174 greg 2.9 int main(int argc, char** argv)
175 greg 2.1 {
176     int i;
177    
178     progname = argv[0];
179     if (argc == 2 && !strcmp(argv[1], "-defaults")) {
180     printdefaults();
181 greg 2.9 return 0;
182 greg 2.1 }
183     if (argc < 4)
184 greg 2.14 usage_error("arg count");
185 greg 2.1 if (!strcmp(argv[1], "-ang")) {
186 greg 2.9 altitude = atof(argv[2]) * (M_PI/180);
187     azimuth = atof(argv[3]) * (M_PI/180);
188 greg 2.1 month = 0;
189     } else {
190     month = atoi(argv[1]);
191     if (month < 1 || month > 12)
192 greg 2.14 usage_error("bad month");
193 greg 2.1 day = atoi(argv[2]);
194     if (day < 1 || day > 31)
195 greg 2.14 usage_error("bad day");
196 greg 2.1 hour = atof(argv[3]);
197     if (hour < 0 || hour >= 24)
198 greg 2.14 usage_error("bad hour");
199 greg 2.1 tsolar = argv[3][0] == '+';
200     }
201     for (i = 4; i < argc; i++)
202     if (argv[i][0] == '-' || argv[i][0] == '+')
203     switch (argv[i][1]) {
204     case 's':
205     cloudy = 0;
206     dosun = argv[i][0] == '+';
207     break;
208     case 'R':
209     u_solar = argv[i][1] == 'R' ? -1 : 1;
210     solarbr = atof(argv[++i]);
211     break;
212     case 'c':
213     cloudy = argv[i][0] == '+' ? 2 : 1;
214     dosun = 0;
215     break;
216     case 't':
217     betaturbidity = atof(argv[++i]);
218     break;
219 greg 2.9 case 'w':
220     suppress_warnings = 1;
221     break;
222 greg 2.1 case 'b':
223     zenithbr = atof(argv[++i]);
224     break;
225     case 'g':
226     gprefl = atof(argv[++i]);
227     break;
228     case 'a':
229 greg 2.9 s_latitude = atof(argv[++i]) * (M_PI/180);
230 greg 2.1 break;
231     case 'o':
232 greg 2.9 s_longitude = atof(argv[++i]) * (M_PI/180);
233 greg 2.1 break;
234     case 'm':
235 greg 2.9 s_meridian = atof(argv[++i]) * (M_PI/180);
236 greg 2.1 break;
237    
238     case 'O':
239 greg 2.14 output = atof(argv[++i]); /*define the unit of the output of the program:
240     sky and sun luminance/radiance
241     (0==W visible, 1==W solar radiation, 2==lm) */
242 greg 2.1 break;
243    
244     case 'P':
245     input = 0; /* Perez parameters: epsilon, delta */
246     skyclearness = atof(argv[++i]);
247     skybrightness = atof(argv[++i]);
248     break;
249    
250     case 'W': /* direct normal Irradiance [W/m^2] */
251     input = 1; /* diffuse horizontal Irrad. [W/m^2] */
252     directirradiance = atof(argv[++i]);
253 greg 2.9 diffuseirradiance = atof(argv[++i]);
254 greg 2.1 break;
255    
256     case 'L': /* direct normal Illuminance [Lux] */
257     input = 2; /* diffuse horizontal Ill. [Lux] */
258     directilluminance = atof(argv[++i]);
259 greg 2.9 diffuseilluminance = atof(argv[++i]);
260 greg 2.1 break;
261    
262     case 'G': /* direct horizontal Irradiance [W/m^2] */
263     input = 3; /* diffuse horizontal Irrad. [W/m^2] */
264     directirradiance = atof(argv[++i]);
265 greg 2.9 diffuseirradiance = atof(argv[++i]);
266     break;
267    
268 greg 2.12 case 'E': /* Erbs model based on the */
269     input = 4; /* global-horizontal irradiance [W/m^2] */
270     globalirradiance = atof(argv[++i]);
271     break;
272    
273     case 'i':
274     timeinterval = atof(argv[++i]);
275     break;
276 greg 2.9
277 greg 2.1
278     default:
279     sprintf(errmsg, "unknown option: %s", argv[i]);
280 greg 2.14 usage_error(errmsg);
281 greg 2.1 }
282     else
283 greg 2.14 usage_error("bad option");
284 greg 2.1
285 greg 2.14 if (month && !tsolar && fabs(s_meridian-s_longitude) > 45*M_PI/180)
286     fprintf(stderr,"%s: warning: %.1f hours btwn. standard meridian and longitude\n",
287 greg 2.9 progname, (s_longitude-s_meridian)*12/M_PI);
288 greg 2.1
289    
290 greg 2.12 /* dynamic memory allocation for the pointers */
291 greg 2.9 if ( (c_perez = calloc(5, sizeof(double))) == NULL )
292 greg 2.14 { fprintf(stderr,"Out of memory error in function main"); return 1; }
293 greg 2.1
294 greg 2.14
295 greg 2.1 printhead(argc, argv);
296     computesky();
297     printsky();
298 greg 2.9 return 0;
299 greg 2.14
300 greg 2.1 }
301    
302    
303 greg 2.12
304    
305    
306     void computesky()
307 greg 2.1 {
308    
309 greg 2.6 int j;
310 greg 2.12
311     float *lv_mod; /* 145 luminance values */
312 greg 2.9 float *theta_o, *phi_o;
313 greg 2.1 double dzeta, gamma;
314     double normfactor;
315 greg 2.12 double erbs_s0, erbs_kt;
316 greg 2.1
317    
318     /* compute solar direction */
319 greg 2.12
320 greg 2.1 if (month) { /* from date and time */
321     int jd;
322 greg 2.14 double sd;
323 greg 2.1
324     jd = jdate(month, day); /* Julian date */
325     sd = sdec(jd); /* solar declination */
326     if (tsolar) /* solar time */
327     st = hour;
328     else
329     st = hour + stadj(jd);
330 greg 2.12
331    
332     if(timeinterval) {
333    
334     if(timeinterval<0) {
335     fprintf(stderr, "time interval negative\n");
336     exit(1);
337     }
338 greg 2.14
339     if(fabs(solar_sunrise(month,day)-st)<=timeinterval/120) {
340     st= (st+timeinterval/120+solar_sunrise(month,day))/2;
341     if(suppress_warnings==0)
342     { fprintf(stderr, "Solar position corrected at time step %d %d %.3f\n",month,day,hour); }
343 greg 2.12 }
344    
345 greg 2.14 if(fabs(solar_sunset(month,day)-st)<timeinterval/120) {
346     st= (st-timeinterval/120+solar_sunset(month,day))/2;
347     if(suppress_warnings==0)
348     { fprintf(stderr, "Solar position corrected at time step %d %d %.3f\n",month,day,hour); }
349 greg 2.12 }
350 greg 2.14
351     if((st<solar_sunrise(month,day)-timeinterval/120) || (st>solar_sunset(month,day)+timeinterval/120)) {
352     if(suppress_warnings==0)
353     { fprintf(stderr, "Warning: sun position too low, printing error sky at %d %d %.3f\n",month,day,hour); }
354     altitude = salt(sd, st);
355     azimuth = sazi(sd, st);
356     print_error_sky();
357     exit(0);
358     }
359 greg 2.12 }
360 greg 2.14 else
361 greg 2.12
362 greg 2.14 if(st<solar_sunrise(month,day) || st>solar_sunset(month,day)) {
363     if(suppress_warnings==0)
364     { fprintf(stderr, "Warning: sun altitude below zero at time step %i %i %.2f, printing error sky\n",month,day,hour); }
365     altitude = salt(sd, st);
366     azimuth = sazi(sd, st);
367     print_error_sky();
368     exit(0);
369     }
370 greg 2.12
371 greg 2.1 altitude = salt(sd, st);
372     azimuth = sazi(sd, st);
373    
374     daynumber = (double)jdate(month, day);
375 greg 2.12
376 greg 2.1 }
377 greg 2.9
378    
379 greg 2.12
380    
381 greg 2.9
382     if (!cloudy && altitude > 87.*M_PI/180.) {
383    
384     if (suppress_warnings==0) {
385     fprintf(stderr,
386 greg 2.1 "%s: warning - sun too close to zenith, reducing altitude to 87 degrees\n",
387     progname);
388 greg 2.9 }
389     altitude = 87.*M_PI/180.;
390 greg 2.1 }
391 greg 2.9
392 greg 2.14
393    
394 greg 2.1 sundir[0] = -sin(azimuth)*cos(altitude);
395     sundir[1] = -cos(azimuth)*cos(altitude);
396     sundir[2] = sin(altitude);
397    
398    
399     /* calculation for the new functions */
400 greg 2.9 sunzenith = 90 - altitude*180/M_PI;
401 greg 2.14
402 greg 2.1
403 greg 2.9 /* compute the inputs for the calculation of the light distribution over the sky*/
404 greg 2.12 if (input==0) /* P */
405 greg 2.1 {
406     check_parametrization();
407 greg 2.9 diffuseirradiance = diffuse_irradiance_from_sky_brightness(); /*diffuse horizontal irradiance*/
408 greg 2.1 directirradiance = direct_irradiance_from_sky_clearness();
409     check_irradiances();
410    
411     if (output==0 || output==2)
412     {
413 greg 2.9 diffuseilluminance = diffuseirradiance*glob_h_diffuse_effi_PEREZ();/*diffuse horizontal illuminance*/
414 greg 2.1 directilluminance = directirradiance*direct_n_effi_PEREZ();
415     check_illuminances();
416     }
417     }
418    
419    
420 greg 2.12 else if (input==1) /* W */
421 greg 2.1 {
422     check_irradiances();
423     skybrightness = sky_brightness();
424     skyclearness = sky_clearness();
425 greg 2.14
426 greg 2.1 check_parametrization();
427 greg 2.14
428 greg 2.1 if (output==0 || output==2)
429     {
430 greg 2.9 diffuseilluminance = diffuseirradiance*glob_h_diffuse_effi_PEREZ();/*diffuse horizontal illuminance*/
431 greg 2.1 directilluminance = directirradiance*direct_n_effi_PEREZ();
432     check_illuminances();
433     }
434    
435     }
436    
437    
438 greg 2.12 else if (input==2) /* L */
439 greg 2.1 {
440     check_illuminances();
441     illu_to_irra_index();
442     check_parametrization();
443     }
444    
445    
446 greg 2.12 else if (input==3) /* G */
447 greg 2.1 {
448     if (altitude<=0)
449     {
450 greg 2.9 if (suppress_warnings==0)
451 greg 2.14 fprintf(stderr, "Warning: sun altitude < 0, proceed with irradiance values of zero\n");
452 greg 2.9 directirradiance = 0;
453     diffuseirradiance = 0;
454     } else {
455 greg 2.12
456     directirradiance=directirradiance/sin(altitude);
457 greg 2.1 }
458 greg 2.12
459 greg 2.1 check_irradiances();
460     skybrightness = sky_brightness();
461     skyclearness = sky_clearness();
462     check_parametrization();
463    
464     if (output==0 || output==2)
465     {
466 greg 2.9 diffuseilluminance = diffuseirradiance*glob_h_diffuse_effi_PEREZ();/*diffuse horizontal illuminance*/
467 greg 2.1 directilluminance = directirradiance*direct_n_effi_PEREZ();
468     check_illuminances();
469     }
470    
471     }
472    
473 greg 2.12
474     else if (input==4) /* E */ /* Implementation of the Erbs model. W.Sprenger (04/13) */
475     {
476    
477     if (altitude<=0)
478     {
479     if (suppress_warnings==0 && globalirradiance > 50)
480     fprintf(stderr, "Warning: global irradiance higher than 50 W/m^2 while the sun altitude is lower than zero\n");
481     globalirradiance = 0; diffuseirradiance = 0; directirradiance = 0;
482    
483     } else {
484    
485     erbs_s0 = solar_constant_e*get_eccentricity()*sin(altitude);
486    
487     if (globalirradiance>erbs_s0)
488     {
489     if (suppress_warnings==0)
490     fprintf(stderr, "Warning: global irradiance is higher than the time-dependent solar constant s0\n");
491     globalirradiance=erbs_s0*0.999;
492     }
493    
494     erbs_kt=globalirradiance/erbs_s0;
495    
496     if (erbs_kt<=0.22) diffuseirradiance=globalirradiance*(1-0.09*erbs_kt);
497     else if (erbs_kt<=0.8) diffuseirradiance=globalirradiance*(0.9511-0.1604*erbs_kt+4.388*pow(erbs_kt,2)-16.638*pow(erbs_kt,3)+12.336*pow(erbs_kt,4));
498     else if (erbs_kt<1) diffuseirradiance=globalirradiance*(0.165);
499    
500     directirradiance=globalirradiance-diffuseirradiance;
501    
502     printf("# erbs_s0, erbs_kt, irr_dir_h, irr_diff: %.3f %.3f %.3f %.3f\n", erbs_s0, erbs_kt, directirradiance, diffuseirradiance);
503 greg 2.14 printf("# WARNING: the -E option is only recommended for a rough estimation!\n");
504 greg 2.12
505     directirradiance=directirradiance/sin(altitude);
506    
507     }
508    
509     check_irradiances();
510     skybrightness = sky_brightness();
511     skyclearness = sky_clearness();
512     check_parametrization();
513    
514     if (output==0 || output==2)
515     {
516     diffuseilluminance = diffuseirradiance*glob_h_diffuse_effi_PEREZ();/*diffuse horizontal illuminance*/
517     directilluminance = directirradiance*direct_n_effi_PEREZ();
518     check_illuminances();
519     }
520    
521     }
522    
523    
524    
525 greg 2.1
526 greg 2.14 else { fprintf(stderr,"error at the input arguments"); exit(1); }
527 greg 2.1
528    
529    
530 greg 2.9 /* normalization factor for the relative sky luminance distribution, diffuse part*/
531 greg 2.12
532 greg 2.1 if ( (lv_mod = malloc(145*sizeof(float))) == NULL)
533     {
534     fprintf(stderr,"Out of memory in function main");
535     exit(1);
536     }
537    
538     /* read the angles */
539 greg 2.9 theta_o = defangle_theta;
540     phi_o = defangle_phi;
541 greg 2.12
542 greg 2.1
543 greg 2.9 /* parameters for the perez model */
544 greg 2.1 coeff_lum_perez(radians(sunzenith), skyclearness, skybrightness, coeff_perez);
545    
546 greg 2.12
547    
548 greg 2.9 /*calculation of the modelled luminance */
549 greg 2.1 for (j=0;j<145;j++)
550     {
551     theta_phi_to_dzeta_gamma(radians(*(theta_o+j)),radians(*(phi_o+j)),&dzeta,&gamma,radians(sunzenith));
552 greg 2.12
553 greg 2.1 *(lv_mod+j) = calc_rel_lum_perez(dzeta,gamma,radians(sunzenith),skyclearness,skybrightness,coeff_perez);
554 greg 2.12
555     /* fprintf(stderr,"theta, phi, lv_mod %f\t %f\t %f\n", *(theta_o+j),*(phi_o+j),*(lv_mod+j)); */
556 greg 2.1 }
557 greg 2.12
558 greg 2.1 /* integration of luminance for the normalization factor, diffuse part of the sky*/
559 greg 2.12
560 greg 2.1 diffnormalization = integ_lv(lv_mod, theta_o);
561    
562    
563    
564 greg 2.9 /*normalization coefficient in lumen or in watt*/
565 greg 2.1 if (output==0)
566     {
567 greg 2.9 diffnormalization = diffuseilluminance/diffnormalization/WHTEFFICACY;
568 greg 2.1 }
569     else if (output==1)
570     {
571 greg 2.9 diffnormalization = diffuseirradiance/diffnormalization;
572 greg 2.1 }
573     else if (output==2)
574     {
575 greg 2.9 diffnormalization = diffuseilluminance/diffnormalization;
576 greg 2.1 }
577    
578 greg 2.9 else {fprintf(stderr,"Wrong output specification.\n"); exit(1);}
579 greg 2.1
580    
581    
582    
583 greg 2.9 /* calculation for the solar source */
584 greg 2.1 if (output==0)
585 greg 2.9 solarradiance = directilluminance/(2*M_PI*(1-cos(half_sun_angle*M_PI/180)))/WHTEFFICACY;
586 greg 2.1
587     else if (output==1)
588 greg 2.9 solarradiance = directirradiance/(2*M_PI*(1-cos(half_sun_angle*M_PI/180)));
589 greg 2.1
590     else
591 greg 2.9 solarradiance = directilluminance/(2*M_PI*(1-cos(half_sun_angle*M_PI/180)));
592 greg 2.1
593    
594    
595 greg 2.14 /* Compute the ground radiance */
596     zenithbr=calc_rel_lum_perez(0.0,radians(sunzenith),radians(sunzenith),skyclearness,skybrightness,coeff_perez);
597     zenithbr*=diffnormalization;
598 greg 2.9
599 greg 2.14 if (skyclearness==1)
600 greg 2.1 normfactor = 0.777778;
601    
602 greg 2.14 if (skyclearness>=6)
603 greg 2.1 {
604 greg 2.9 F2 = 0.274*(0.91 + 10.0*exp(-3.0*(M_PI/2.0-altitude)) + 0.45*sundir[2]*sundir[2]);
605     normfactor = normsc()/F2/M_PI;
606 greg 2.1 }
607    
608 greg 2.14 if ( (skyclearness>1) && (skyclearness<6) )
609 greg 2.1 {
610     S_INTER=1;
611 greg 2.9 F2 = (2.739 + .9891*sin(.3119+2.6*altitude)) * exp(-(M_PI/2.0-altitude)*(.4441+1.48*altitude));
612     normfactor = normsc()/F2/M_PI;
613 greg 2.1 }
614    
615 greg 2.14 groundbr = zenithbr*normfactor;
616 greg 2.1
617 greg 2.14 if (dosun&&(skyclearness>1))
618 greg 2.9 groundbr += 6.8e-5/M_PI*solarradiance*sundir[2];
619 greg 2.1
620 greg 2.14 groundbr *= gprefl;
621 greg 2.1
622    
623 greg 2.14
624     if(*(c_perez+1)>0)
625     {
626     if(suppress_warnings==0)
627     { fprintf(stderr, "Warning: positive Perez parameter B (= %lf), printing error sky\n",*(c_perez+1));}
628     print_error_sky();
629     exit(0);
630     }
631    
632 greg 2.1
633     return;
634     }
635    
636    
637    
638    
639 greg 2.12
640     double solar_sunset(int month,int day)
641     {
642     float W;
643     extern double s_latitude;
644     W=-1*(tan(s_latitude)*tan(sdec(jdate(month, day))));
645     return(12+(M_PI/2 - atan2(W,sqrt(1-W*W)))*180/(M_PI*15));
646     }
647    
648    
649 greg 2.14
650    
651 greg 2.12 double solar_sunrise(int month,int day)
652     {
653     float W;
654     extern double s_latitude;
655     W=-1*(tan(s_latitude)*tan(sdec(jdate(month, day))));
656     return(12-(M_PI/2 - atan2(W,sqrt(1-W*W)))*180/(M_PI*15));
657     }
658    
659    
660    
661    
662 greg 2.14 void printsky()
663     {
664    
665     printf("# Local solar time: %.2f\n", st);
666     printf("# Solar altitude and azimuth: %.1f %.1f\n", altitude*180/M_PI, azimuth*180/M_PI);
667 greg 2.12
668    
669 greg 2.1 if (dosun&&(skyclearness>1))
670 greg 2.9 {
671 greg 2.1 printf("\nvoid light solar\n");
672     printf("0\n0\n");
673     printf("3 %.3e %.3e %.3e\n", solarradiance, solarradiance, solarradiance);
674     printf("\nsolar source sun\n");
675     printf("0\n0\n");
676     printf("4 %f %f %f %f\n", sundir[0], sundir[1], sundir[2], 2*half_sun_angle);
677 greg 2.9 } else if (dosun) {
678 greg 2.1 printf("\nvoid light solar\n");
679     printf("0\n0\n");
680     printf("3 0.0 0.0 0.0\n");
681     printf("\nsolar source sun\n");
682     printf("0\n0\n");
683     printf("4 %f %f %f %f\n", sundir[0], sundir[1], sundir[2], 2*half_sun_angle);
684 greg 2.9 }
685 greg 2.1
686 greg 2.12
687 greg 2.1 printf("\nvoid brightfunc skyfunc\n");
688     printf("2 skybright perezlum.cal\n");
689     printf("0\n");
690     printf("10 %.3e %.3e %lf %lf %lf %lf %lf %f %f %f \n", diffnormalization, groundbr,
691 greg 2.9 *(c_perez+0),*(c_perez+1),*(c_perez+2),*(c_perez+3),*(c_perez+4),
692     sundir[0], sundir[1], sundir[2]);
693 greg 2.12
694 greg 2.1 }
695    
696    
697 greg 2.14
698     void print_error_sky()
699     {
700    
701    
702     sundir[0] = -sin(azimuth)*cos(altitude);
703     sundir[1] = -cos(azimuth)*cos(altitude);
704     sundir[2] = sin(altitude);
705    
706     printf("# Local solar time: %.2f\n", st);
707     printf("# Solar altitude and azimuth: %.1f %.1f\n", altitude*180/M_PI, azimuth*180/M_PI);
708    
709     printf("\nvoid brightfunc skyfunc\n");
710     printf("2 skybright perezlum.cal\n");
711     printf("0\n");
712     printf("10 0.00 0.00 0.000 0.000 0.000 0.000 0.000 %f %f %f \n", sundir[0], sundir[1], sundir[2]);
713     }
714    
715    
716    
717    
718    
719 greg 2.9 void printdefaults() /* print default values */
720 greg 2.1 {
721     printf("-g %f\t\t\t# Ground plane reflectance\n", gprefl);
722     if (zenithbr > 0.0)
723     printf("-b %f\t\t\t# Zenith radiance (watts/ster/m^2\n", zenithbr);
724     else
725     printf("-t %f\t\t\t# Atmospheric betaturbidity\n", betaturbidity);
726 greg 2.9 printf("-a %f\t\t\t# Site latitude (degrees)\n", s_latitude*(180/M_PI));
727     printf("-o %f\t\t\t# Site longitude (degrees)\n", s_longitude*(180/M_PI));
728     printf("-m %f\t\t\t# Standard meridian (degrees)\n", s_meridian*(180/M_PI));
729 greg 2.1 }
730    
731    
732 greg 2.14
733    
734     void usage_error(char* msg) /* print usage error and quit */
735 greg 2.1 {
736     if (msg != NULL)
737 greg 2.12 fprintf(stderr, "%s: Use error - %s\n\n", progname, msg);
738     fprintf(stderr, "Usage: %s month day hour [...]\n", progname);
739     fprintf(stderr, " or: %s -ang altitude azimuth [...]\n", progname);
740     fprintf(stderr, " followed by: -P epsilon delta [options]\n");
741     fprintf(stderr, " or: [-W|-L|-G] direct_value diffuse_value [options]\n");
742     fprintf(stderr, " or: -E global_irradiance [options]\n\n");
743     fprintf(stderr, " Description:\n");
744 greg 2.1 fprintf(stderr, " -P epsilon delta (these are the Perez parameters) \n");
745     fprintf(stderr, " -W direct-normal-irradiance diffuse-horizontal-irradiance (W/m^2)\n");
746     fprintf(stderr, " -L direct-normal-illuminance diffuse-horizontal-illuminance (lux)\n");
747     fprintf(stderr, " -G direct-horizontal-irradiance diffuse-horizontal-irradiance (W/m^2)\n");
748 greg 2.12 fprintf(stderr, " -E global-horizontal-irradiance (W/m^2)\n\n");
749     fprintf(stderr, " Output specification with option:\n");
750 greg 2.1 fprintf(stderr, " -O [0|1|2] (0=output in W/m^2/sr visible, 1=output in W/m^2/sr solar, 2=output in candela/m^2), default is 0 \n");
751 greg 2.14 fprintf(stderr, " gendaylit version 2.4 (2013/09/04) \n\n");
752 greg 2.1 exit(1);
753     }
754    
755    
756    
757 greg 2.14
758 greg 2.9 double normsc() /* compute normalization factor (E0*F2/L0) */
759 greg 2.1 {
760     static double nfc[2][5] = {
761     /* clear sky approx. */
762     {2.766521, 0.547665, -0.369832, 0.009237, 0.059229},
763     /* intermediate sky approx. */
764     {3.5556, -2.7152, -1.3081, 1.0660, 0.60227},
765     };
766     register double *nf;
767     double x, nsc;
768     register int i;
769     /* polynomial approximation */
770     nf = nfc[S_INTER];
771 greg 2.9 x = (altitude - M_PI/4.0)/(M_PI/4.0);
772 greg 2.1 nsc = nf[i=4];
773     while (i--)
774     nsc = nsc*x + nf[i];
775    
776     return(nsc);
777     }
778    
779    
780    
781 greg 2.14
782    
783 greg 2.9 void printhead(int ac, char** av) /* print command header */
784 greg 2.1 {
785     putchar('#');
786     while (ac--) {
787     putchar(' ');
788     fputs(*av++, stdout);
789     }
790     putchar('\n');
791     }
792    
793    
794    
795    
796 greg 2.14
797    
798 greg 2.1 /* Perez models */
799    
800     /* Perez global horizontal luminous efficacy model */
801     double glob_h_effi_PEREZ()
802     {
803    
804     double value;
805     double category_bounds[10], a[10], b[10], c[10], d[10];
806     int category_total_number, category_number, i;
807 greg 2.12
808     check_parametrization();
809    
810    
811     /*if ((skyclearness<skyclearinf || skyclearness>skyclearsup || skybrightness<skybriginf || skybrightness>skybrigsup) && suppress_warnings==0)
812     fprintf(stderr, "Warning: skyclearness or skybrightness out of range in function glob_h_effi_PEREZ \n"); */
813    
814    
815 greg 2.1 /* initialize category bounds (clearness index bounds) */
816    
817     category_total_number = 8;
818    
819     category_bounds[1] = 1;
820     category_bounds[2] = 1.065;
821     category_bounds[3] = 1.230;
822     category_bounds[4] = 1.500;
823     category_bounds[5] = 1.950;
824     category_bounds[6] = 2.800;
825     category_bounds[7] = 4.500;
826     category_bounds[8] = 6.200;
827     category_bounds[9] = 12.01;
828    
829    
830     /* initialize model coefficients */
831     a[1] = 96.63;
832     a[2] = 107.54;
833     a[3] = 98.73;
834     a[4] = 92.72;
835     a[5] = 86.73;
836     a[6] = 88.34;
837     a[7] = 78.63;
838     a[8] = 99.65;
839    
840     b[1] = -0.47;
841     b[2] = 0.79;
842     b[3] = 0.70;
843     b[4] = 0.56;
844     b[5] = 0.98;
845     b[6] = 1.39;
846     b[7] = 1.47;
847     b[8] = 1.86;
848    
849     c[1] = 11.50;
850     c[2] = 1.79;
851     c[3] = 4.40;
852     c[4] = 8.36;
853     c[5] = 7.10;
854     c[6] = 6.06;
855     c[7] = 4.93;
856     c[8] = -4.46;
857    
858     d[1] = -9.16;
859     d[2] = -1.19;
860     d[3] = -6.95;
861     d[4] = -8.31;
862     d[5] = -10.94;
863     d[6] = -7.60;
864     d[7] = -11.37;
865     d[8] = -3.15;
866    
867    
868    
869     for (i=1; i<=category_total_number; i++)
870     {
871     if ( (skyclearness >= category_bounds[i]) && (skyclearness < category_bounds[i+1]) )
872     category_number = i;
873     }
874    
875     value = a[category_number] + b[category_number]*atm_preci_water +
876 greg 2.9 c[category_number]*cos(sunzenith*M_PI/180) + d[category_number]*log(skybrightness);
877 greg 2.1
878     return(value);
879     }
880    
881    
882 greg 2.14
883    
884 greg 2.1 /* global horizontal diffuse efficacy model, according to PEREZ */
885     double glob_h_diffuse_effi_PEREZ()
886     {
887     double value;
888     double category_bounds[10], a[10], b[10], c[10], d[10];
889     int category_total_number, category_number, i;
890    
891 greg 2.12 check_parametrization();
892 greg 2.1
893 greg 2.12
894     /*if ((skyclearness<skyclearinf || skyclearness>skyclearsup || skybrightness<skybriginf || skybrightness>skybrigsup) && suppress_warnings==0)
895 greg 2.14 fprintf(stderr, "Warning: skyclearness or skybrightness out of range in function glob_h_diffuse_PEREZ \n"); */
896 greg 2.12
897 greg 2.1 /* initialize category bounds (clearness index bounds) */
898    
899     category_total_number = 8;
900    
901 greg 2.12 //XXX: category_bounds > 0.1
902 greg 2.1 category_bounds[1] = 1;
903     category_bounds[2] = 1.065;
904     category_bounds[3] = 1.230;
905     category_bounds[4] = 1.500;
906     category_bounds[5] = 1.950;
907     category_bounds[6] = 2.800;
908     category_bounds[7] = 4.500;
909     category_bounds[8] = 6.200;
910     category_bounds[9] = 12.01;
911    
912    
913     /* initialize model coefficients */
914     a[1] = 97.24;
915     a[2] = 107.22;
916     a[3] = 104.97;
917     a[4] = 102.39;
918     a[5] = 100.71;
919     a[6] = 106.42;
920     a[7] = 141.88;
921     a[8] = 152.23;
922    
923     b[1] = -0.46;
924     b[2] = 1.15;
925     b[3] = 2.96;
926     b[4] = 5.59;
927     b[5] = 5.94;
928     b[6] = 3.83;
929     b[7] = 1.90;
930     b[8] = 0.35;
931    
932     c[1] = 12.00;
933     c[2] = 0.59;
934     c[3] = -5.53;
935     c[4] = -13.95;
936     c[5] = -22.75;
937     c[6] = -36.15;
938     c[7] = -53.24;
939     c[8] = -45.27;
940    
941     d[1] = -8.91;
942     d[2] = -3.95;
943     d[3] = -8.77;
944     d[4] = -13.90;
945     d[5] = -23.74;
946     d[6] = -28.83;
947     d[7] = -14.03;
948     d[8] = -7.98;
949    
950    
951    
952 greg 2.9 category_number = -1;
953 greg 2.1 for (i=1; i<=category_total_number; i++)
954     {
955     if ( (skyclearness >= category_bounds[i]) && (skyclearness < category_bounds[i+1]) )
956     category_number = i;
957     }
958    
959 greg 2.9 if (category_number == -1) {
960     if (suppress_warnings==0)
961 greg 2.14 fprintf(stderr, "Warning: sky clearness (= %.3f) too high, printing error sky\n", skyclearness);
962 greg 2.9 print_error_sky();
963 greg 2.14 exit(0);
964 greg 2.9 }
965    
966    
967     value = a[category_number] + b[category_number]*atm_preci_water + c[category_number]*cos(sunzenith*M_PI/180) +
968 greg 2.1 d[category_number]*log(skybrightness);
969    
970     return(value);
971 greg 2.12
972 greg 2.1 }
973    
974    
975 greg 2.12
976 greg 2.14
977    
978    
979 greg 2.1 /* direct normal efficacy model, according to PEREZ */
980    
981     double direct_n_effi_PEREZ()
982    
983     {
984     double value;
985     double category_bounds[10], a[10], b[10], c[10], d[10];
986     int category_total_number, category_number, i;
987    
988    
989 greg 2.14 /*if ((skyclearness<skyclearinf || skyclearness>skyclearsup || skybrightness<skybriginf || skybrightness>skybrigsup) && suppress_warnings==0)
990     fprintf(stderr, "Warning: skyclearness or skybrightness out of range in function direct_n_effi_PEREZ \n");*/
991 greg 2.1
992    
993     /* initialize category bounds (clearness index bounds) */
994    
995     category_total_number = 8;
996    
997     category_bounds[1] = 1;
998     category_bounds[2] = 1.065;
999     category_bounds[3] = 1.230;
1000     category_bounds[4] = 1.500;
1001     category_bounds[5] = 1.950;
1002     category_bounds[6] = 2.800;
1003     category_bounds[7] = 4.500;
1004     category_bounds[8] = 6.200;
1005     category_bounds[9] = 12.1;
1006    
1007    
1008     /* initialize model coefficients */
1009     a[1] = 57.20;
1010     a[2] = 98.99;
1011     a[3] = 109.83;
1012     a[4] = 110.34;
1013     a[5] = 106.36;
1014     a[6] = 107.19;
1015     a[7] = 105.75;
1016     a[8] = 101.18;
1017    
1018     b[1] = -4.55;
1019     b[2] = -3.46;
1020     b[3] = -4.90;
1021     b[4] = -5.84;
1022     b[5] = -3.97;
1023     b[6] = -1.25;
1024     b[7] = 0.77;
1025     b[8] = 1.58;
1026    
1027     c[1] = -2.98;
1028     c[2] = -1.21;
1029     c[3] = -1.71;
1030     c[4] = -1.99;
1031     c[5] = -1.75;
1032     c[6] = -1.51;
1033     c[7] = -1.26;
1034     c[8] = -1.10;
1035    
1036     d[1] = 117.12;
1037     d[2] = 12.38;
1038     d[3] = -8.81;
1039     d[4] = -4.56;
1040     d[5] = -6.16;
1041     d[6] = -26.73;
1042     d[7] = -34.44;
1043     d[8] = -8.29;
1044    
1045    
1046    
1047     for (i=1; i<=category_total_number; i++)
1048     {
1049     if ( (skyclearness >= category_bounds[i]) && (skyclearness < category_bounds[i+1]) )
1050     category_number = i;
1051     }
1052    
1053 greg 2.9 value = a[category_number] + b[category_number]*atm_preci_water + c[category_number]*exp(5.73*sunzenith*M_PI/180 - 5) + d[category_number]*skybrightness;
1054 greg 2.1
1055     if (value < 0) value = 0;
1056    
1057     return(value);
1058     }
1059    
1060    
1061     /*check the range of epsilon and delta indexes of the perez parametrization*/
1062     void check_parametrization()
1063     {
1064 greg 2.14
1065 greg 2.9 if (skyclearness<skyclearinf || skyclearness>skyclearsup || skybrightness<skybriginf || skybrightness>skybrigsup)
1066 greg 2.1 {
1067 greg 2.9
1068     /* limit sky clearness or sky brightness, 2009 11 13 by J. Wienold */
1069 greg 2.14
1070 greg 2.9 if (skyclearness<skyclearinf){
1071 greg 2.14 /* if (suppress_warnings==0)
1072     fprintf(stderr,"Range warning: sky clearness too low (%lf)\n", skyclearness); */
1073 greg 2.9 skyclearness=skyclearinf;
1074     }
1075     if (skyclearness>skyclearsup){
1076 greg 2.14 /* if (suppress_warnings==0)
1077     fprintf(stderr,"Range warning: sky clearness too high (%lf)\n", skyclearness); */
1078     skyclearness=skyclearsup-0.001;
1079 greg 2.9 }
1080     if (skybrightness<skybriginf){
1081 greg 2.14 /* if (suppress_warnings==0)
1082     fprintf(stderr,"Range warning: sky brightness too low (%lf)\n", skybrightness); */
1083 greg 2.9 skybrightness=skybriginf;
1084     }
1085     if (skybrightness>skybrigsup){
1086 greg 2.14 /* if (suppress_warnings==0)
1087     fprintf(stderr,"Range warning: sky brightness too high (%lf)\n", skybrightness); */
1088 greg 2.9 skybrightness=skybrigsup;
1089 greg 2.1 }
1090 greg 2.9
1091     return; }
1092 greg 2.1 else return;
1093     }
1094    
1095    
1096 greg 2.14
1097    
1098    
1099 greg 2.9 /* validity of the direct and diffuse components */
1100 greg 2.1 void check_illuminances()
1101     {
1102 greg 2.9 if (directilluminance < 0) {
1103 greg 2.14 if(suppress_warnings==0)
1104     { fprintf(stderr,"Warning: direct illuminance < 0. Using 0.0\n"); }
1105 greg 2.9 directilluminance = 0.0;
1106     }
1107     if (diffuseilluminance < 0) {
1108 greg 2.14 if(suppress_warnings==0)
1109     { fprintf(stderr,"Warning: diffuse illuminance < 0. Using 0.0\n"); }
1110 greg 2.9 diffuseilluminance = 0.0;
1111     }
1112 greg 2.14
1113     if (directilluminance+diffuseilluminance==0 && altitude > 0) {
1114     if(suppress_warnings==0)
1115     { fprintf(stderr,"Warning: zero illuminance at sun altitude > 0, printing error sky\n"); }
1116     print_error_sky();
1117     exit(0);
1118     }
1119    
1120     if (directilluminance > solar_constant_l) {
1121     if(suppress_warnings==0)
1122     { fprintf(stderr,"Warning: direct illuminance exceeds solar constant\n"); }
1123     print_error_sky();
1124     exit(0);
1125 greg 2.1 }
1126     }
1127    
1128    
1129     void check_irradiances()
1130     {
1131 greg 2.9 if (directirradiance < 0) {
1132 greg 2.14 if(suppress_warnings==0)
1133     { fprintf(stderr,"Warning: direct irradiance < 0. Using 0.0\n"); }
1134 greg 2.9 directirradiance = 0.0;
1135     }
1136     if (diffuseirradiance < 0) {
1137 greg 2.14 if(suppress_warnings==0)
1138     { fprintf(stderr,"Warning: diffuse irradiance < 0. Using 0.0\n"); }
1139 greg 2.9 diffuseirradiance = 0.0;
1140     }
1141 greg 2.14
1142     if (directirradiance+diffuseirradiance==0 && altitude > 0) {
1143     if(suppress_warnings==0)
1144     { fprintf(stderr,"Warning: zero irradiance at sun altitude > 0, printing error sky\n"); }
1145     print_error_sky();
1146     exit(0);
1147     }
1148    
1149 greg 2.9 if (directirradiance > solar_constant_e) {
1150 greg 2.14 if(suppress_warnings==0)
1151     { fprintf(stderr,"Warning: direct irradiance exceeds solar constant\n"); }
1152     print_error_sky();
1153     exit(0);
1154 greg 2.9 }
1155 greg 2.1 }
1156    
1157    
1158    
1159     /* Perez sky's brightness */
1160     double sky_brightness()
1161     {
1162     double value;
1163    
1164 greg 2.9 value = diffuseirradiance * air_mass() / ( solar_constant_e*get_eccentricity());
1165 greg 2.1
1166     return(value);
1167     }
1168    
1169    
1170     /* Perez sky's clearness */
1171     double sky_clearness()
1172     {
1173 greg 2.9 double value;
1174 greg 2.1
1175 greg 2.9 value = ( (diffuseirradiance + directirradiance)/(diffuseirradiance) + 1.041*sunzenith*M_PI/180*sunzenith*M_PI/180*sunzenith*M_PI/180 ) / (1 + 1.041*sunzenith*M_PI/180*sunzenith*M_PI/180*sunzenith*M_PI/180) ;
1176 greg 2.1
1177 greg 2.9 return(value);
1178 greg 2.1 }
1179    
1180    
1181    
1182     /* diffus horizontal irradiance from Perez sky's brightness */
1183 greg 2.9 double diffuse_irradiance_from_sky_brightness()
1184 greg 2.1 {
1185     double value;
1186    
1187     value = skybrightness / air_mass() * ( solar_constant_e*get_eccentricity());
1188    
1189     return(value);
1190     }
1191    
1192    
1193     /* direct normal irradiance from Perez sky's clearness */
1194     double direct_irradiance_from_sky_clearness()
1195     {
1196     double value;
1197    
1198 greg 2.9 value = diffuse_irradiance_from_sky_brightness();
1199     value = value * ( (skyclearness-1) * (1+1.041*sunzenith*M_PI/180*sunzenith*M_PI/180*sunzenith*M_PI/180) );
1200 greg 2.1
1201     return(value);
1202     }
1203    
1204    
1205 greg 2.12
1206    
1207 greg 2.9 void illu_to_irra_index()
1208 greg 2.1 {
1209 greg 2.9 double test1=0.1, test2=0.1, d_eff;
1210 greg 2.1 int counter=0;
1211    
1212 greg 2.14 diffuseirradiance = diffuseilluminance*solar_constant_e/(solar_constant_l);
1213     directirradiance = directilluminance*solar_constant_e/(solar_constant_l);
1214 greg 2.1 skyclearness = sky_clearness();
1215     skybrightness = sky_brightness();
1216 greg 2.9 check_parametrization();
1217 greg 2.12
1218    
1219 greg 2.9 while ( ((fabs(diffuseirradiance-test1)>10) || (fabs(directirradiance-test2)>10)
1220 greg 2.12 || (!(skyclearness<skyclearinf || skyclearness>skyclearsup))
1221     || (!(skybrightness<skybriginf || skybrightness>skybrigsup)) )
1222     && !(counter==9) )
1223 greg 2.1 {
1224 greg 2.12
1225 greg 2.9 test1=diffuseirradiance;
1226 greg 2.1 test2=directirradiance;
1227     counter++;
1228    
1229 greg 2.9 diffuseirradiance = diffuseilluminance/glob_h_diffuse_effi_PEREZ();
1230     d_eff = direct_n_effi_PEREZ();
1231 greg 2.12
1232    
1233 greg 2.9 if (d_eff < 0.1)
1234     directirradiance = 0;
1235 greg 2.12 else
1236 greg 2.9 directirradiance = directilluminance/d_eff;
1237 greg 2.1
1238     skybrightness = sky_brightness();
1239     skyclearness = sky_clearness();
1240 greg 2.9 check_parametrization();
1241 greg 2.12
1242 greg 2.1 }
1243    
1244    
1245     return;
1246     }
1247    
1248 greg 2.9 static int get_numlin(float epsilon)
1249 greg 2.1 {
1250 greg 2.9 if (epsilon < 1.065)
1251     return 0;
1252     else if (epsilon < 1.230)
1253     return 1;
1254     else if (epsilon < 1.500)
1255     return 2;
1256     else if (epsilon < 1.950)
1257     return 3;
1258     else if (epsilon < 2.800)
1259     return 4;
1260     else if (epsilon < 4.500)
1261     return 5;
1262     else if (epsilon < 6.200)
1263     return 6;
1264     return 7;
1265 greg 2.1 }
1266    
1267     /* sky luminance perez model */
1268 greg 2.9 double calc_rel_lum_perez(double dzeta,double gamma,double Z,double epsilon,double Delta,float coeff_perez[])
1269 greg 2.1 {
1270 greg 2.12
1271 greg 2.1 float x[5][4];
1272     int i,j,num_lin;
1273     double c_perez[5];
1274    
1275     if ( (epsilon < skyclearinf) || (epsilon >= skyclearsup) )
1276     {
1277 greg 2.14 fprintf(stderr,"Error: epsilon out of range in function calc_rel_lum_perez!\n");
1278 greg 2.1 exit(1);
1279     }
1280    
1281     /* correction de modele de Perez solar energy ...*/
1282     if ( (epsilon > 1.065) && (epsilon < 2.8) )
1283     {
1284     if ( Delta < 0.2 ) Delta = 0.2;
1285     }
1286 greg 2.12
1287    
1288 greg 2.9 num_lin = get_numlin(epsilon);
1289 greg 2.12
1290 greg 2.1 for (i=0;i<5;i++)
1291     for (j=0;j<4;j++)
1292     {
1293     x[i][j] = *(coeff_perez + 20*num_lin + 4*i +j);
1294 greg 2.12 /* fprintf(stderr,"x %d %d vaut %f\n",i,j,x[i][j]); */
1295 greg 2.1 }
1296    
1297    
1298     if (num_lin)
1299     {
1300     for (i=0;i<5;i++)
1301     c_perez[i] = x[i][0] + x[i][1]*Z + Delta * (x[i][2] + x[i][3]*Z);
1302     }
1303     else
1304     {
1305     c_perez[0] = x[0][0] + x[0][1]*Z + Delta * (x[0][2] + x[0][3]*Z);
1306     c_perez[1] = x[1][0] + x[1][1]*Z + Delta * (x[1][2] + x[1][3]*Z);
1307     c_perez[4] = x[4][0] + x[4][1]*Z + Delta * (x[4][2] + x[4][3]*Z);
1308     c_perez[2] = exp( pow(Delta*(x[2][0]+x[2][1]*Z),x[2][2])) - x[2][3];
1309     c_perez[3] = -exp( Delta*(x[3][0]+x[3][1]*Z) )+x[3][2]+Delta*x[3][3];
1310     }
1311    
1312    
1313     return (1 + c_perez[0]*exp(c_perez[1]/cos(dzeta)) ) *
1314     (1 + c_perez[2]*exp(c_perez[3]*gamma) +
1315     c_perez[4]*cos(gamma)*cos(gamma) );
1316     }
1317    
1318    
1319    
1320     /* coefficients for the sky luminance perez model */
1321 greg 2.9 void coeff_lum_perez(double Z, double epsilon, double Delta, float coeff_perez[])
1322 greg 2.1 {
1323     float x[5][4];
1324     int i,j,num_lin;
1325    
1326     if ( (epsilon < skyclearinf) || (epsilon >= skyclearsup) )
1327     {
1328 greg 2.14 fprintf(stderr,"Error: epsilon out of range in function coeff_lum_perez!\n");
1329 greg 2.1 exit(1);
1330     }
1331    
1332     /* correction du modele de Perez solar energy ...*/
1333     if ( (epsilon > 1.065) && (epsilon < 2.8) )
1334     {
1335     if ( Delta < 0.2 ) Delta = 0.2;
1336     }
1337 greg 2.12
1338    
1339 greg 2.9 num_lin = get_numlin(epsilon);
1340    
1341 greg 2.12 /*fprintf(stderr,"numlin %d\n", num_lin);*/
1342 greg 2.1
1343     for (i=0;i<5;i++)
1344     for (j=0;j<4;j++)
1345     {
1346     x[i][j] = *(coeff_perez + 20*num_lin + 4*i +j);
1347     /* printf("x %d %d vaut %f\n",i,j,x[i][j]); */
1348     }
1349    
1350    
1351     if (num_lin)
1352     {
1353     for (i=0;i<5;i++)
1354     *(c_perez+i) = x[i][0] + x[i][1]*Z + Delta * (x[i][2] + x[i][3]*Z);
1355    
1356     }
1357     else
1358     {
1359     *(c_perez+0) = x[0][0] + x[0][1]*Z + Delta * (x[0][2] + x[0][3]*Z);
1360     *(c_perez+1) = x[1][0] + x[1][1]*Z + Delta * (x[1][2] + x[1][3]*Z);
1361     *(c_perez+4) = x[4][0] + x[4][1]*Z + Delta * (x[4][2] + x[4][3]*Z);
1362     *(c_perez+2) = exp( pow(Delta*(x[2][0]+x[2][1]*Z),x[2][2])) - x[2][3];
1363     *(c_perez+3) = -exp( Delta*(x[3][0]+x[3][1]*Z) )+x[3][2]+Delta*x[3][3];
1364    
1365    
1366     }
1367    
1368    
1369     return;
1370     }
1371    
1372    
1373 greg 2.12
1374 greg 2.1 /* degrees into radians */
1375     double radians(double degres)
1376     {
1377 greg 2.9 return degres*M_PI/180.0;
1378 greg 2.1 }
1379    
1380 greg 2.12
1381 greg 2.1 /* radian into degrees */
1382     double degres(double radians)
1383     {
1384 greg 2.9 return radians/M_PI*180.0;
1385 greg 2.1 }
1386    
1387 greg 2.12
1388 greg 2.1 /* calculation of the angles dzeta and gamma */
1389     void theta_phi_to_dzeta_gamma(double theta,double phi,double *dzeta,double *gamma, double Z)
1390     {
1391     *dzeta = theta; /* dzeta = phi */
1392     if ( (cos(Z)*cos(theta)+sin(Z)*sin(theta)*cos(phi)) > 1 && (cos(Z)*cos(theta)+sin(Z)*sin(theta)*cos(phi) < 1.1 ) )
1393     *gamma = 0;
1394     else if ( (cos(Z)*cos(theta)+sin(Z)*sin(theta)*cos(phi)) > 1.1 )
1395     {
1396     printf("error in calculation of gamma (angle between point and sun");
1397 greg 2.14 exit(1);
1398 greg 2.1 }
1399     else
1400     *gamma = acos(cos(Z)*cos(theta)+sin(Z)*sin(theta)*cos(phi));
1401     }
1402    
1403    
1404    
1405     double integ_lv(float *lv,float *theta)
1406     {
1407     int i;
1408     double buffer=0.0;
1409 greg 2.12
1410 greg 2.1 for (i=0;i<145;i++)
1411 greg 2.12 {
1412 greg 2.1 buffer += (*(lv+i))*cos(radians(*(theta+i)));
1413 greg 2.12 }
1414    
1415 greg 2.9 return buffer*2*M_PI/144;
1416 greg 2.1 }
1417    
1418    
1419    
1420     /* enter day number(double), return E0 = square(R0/R): eccentricity correction factor */
1421    
1422     double get_eccentricity()
1423     {
1424     double day_angle;
1425     double E0;
1426    
1427 greg 2.9 day_angle = 2*M_PI*(daynumber - 1)/365;
1428 greg 2.1 E0 = 1.00011+0.034221*cos(day_angle)+0.00128*sin(day_angle)+
1429     0.000719*cos(2*day_angle)+0.000077*sin(2*day_angle);
1430    
1431     return (E0);
1432     }
1433    
1434    
1435     /* enter sunzenith angle (degrees) return relative air mass (double) */
1436     double air_mass()
1437     {
1438     double m;
1439     if (sunzenith>90)
1440     {
1441 greg 2.14 if(suppress_warnings==0)
1442     { fprintf(stderr, "Warning: air mass has reached the maximal value\n"); }
1443     sunzenith=90;
1444 greg 2.1 }
1445 greg 2.9 m = 1/( cos(sunzenith*M_PI/180)+0.15*exp( log(93.885-sunzenith)*(-1.253) ) );
1446 greg 2.1 return(m);
1447     }
1448    
1449    
1450