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root/radiance/ray/src/gen/gendaylit.c
Revision: 2.12
Committed: Fri Aug 9 16:44:19 2013 UTC (10 years, 8 months ago) by greg
Content type: text/plain
Branch: MAIN
Changes since 2.11: +307 -152 lines
Log Message:
Bug fixes and new -E and -i options (from Wendelin Sprenger and Jan Wienold)

File Contents

# Content
1 /* Copyright (c) 1994,2006 *Fraunhofer Institut for Solar Energy Systems
2 * Heidenhofstr. 2, D-79110 Freiburg, Germany
3 * *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 #include "sun.h"
16 #include "paths.h"
17
18 #define DOT(v1,v2) (v1[0]*v2[0]+v1[1]*v2[1]+v1[2]*v2[2])
19
20 double normsc();
21
22 /*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 $";*/
23
24 float coeff_perez[] = {
25 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,
26 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,
27 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,
28 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,
29 -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,
30 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,
31 -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,
32 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,
33 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,
34 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,
35 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,
36 -14.5000,-46.1148,55.3750,-7.2312,0.4050,13.3500,0.6234,1.5000,-0.6426,1.8564,0.5636};
37
38
39 float defangle_theta[] = {
40 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,
41 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,
42 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,
43 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,
44 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,
45 24, 24, 24, 24, 24, 24, 24, 24, 12, 12, 12, 12, 12, 12, 0};
46
47 float defangle_phi[] = {
48 0, 12, 24, 36, 48, 60, 72, 84, 96, 108, 120, 132, 144, 156, 168, 180, 192, 204, 216, 228, 240, 252, 264,
49 276, 288, 300, 312, 324, 336, 348, 0, 12, 24, 36, 48, 60, 72, 84, 96, 108, 120, 132, 144, 156, 168, 180,
50 192, 204, 216, 228, 240, 252, 264, 276, 288, 300, 312, 324, 336, 348, 0, 15, 30, 45, 60, 75, 90, 105,
51 120, 135, 150, 165, 180, 195, 210, 225, 240, 255, 270, 285, 300, 315, 330, 345, 0, 15, 30, 45, 60, 75,
52 90, 105, 120, 135, 150, 165, 180, 195, 210, 225, 240, 255, 270, 285, 300, 315, 330, 345, 0, 20, 40, 60,
53 80, 100, 120, 140, 160, 180, 200, 220, 240, 260, 280, 300, 320, 340, 0, 30, 60, 90, 120, 150, 180, 210,
54 240, 270, 300, 330, 0, 60, 120, 180, 240, 300, 0};
55
56
57
58 /* Perez sky parametrization : epsilon and delta calculations from the direct and diffuse irradiances */
59 double sky_brightness();
60 double sky_clearness();
61
62 /* calculation of the direct and diffuse components from the Perez parametrization */
63 double diffuse_irradiance_from_sky_brightness();
64 double direct_irradiance_from_sky_clearness();
65
66 /* Perez global horizontal, diffuse horizontal and direct normal luminous efficacy models : */
67 /* input w(cm)=2cm, solar zenith angle(degrees); output efficacy(lm/W) */
68
69 double glob_h_effi_PEREZ();
70 double glob_h_diffuse_effi_PEREZ();
71 double direct_n_effi_PEREZ();
72
73 /*likelihood check of the epsilon, delta, direct and diffuse components*/
74 void check_parametrization();
75 void check_irradiances();
76 void check_illuminances();
77 void illu_to_irra_index();
78 void print_error_sky();
79
80 double calc_rel_lum_perez(double dzeta,double gamma,double Z,double epsilon,double Delta,float coeff_perez[]);
81 void coeff_lum_perez(double Z, double epsilon, double Delta, float coeff_perez[]);
82 double radians(double degres);
83 double degres(double radians);
84 void theta_phi_to_dzeta_gamma(double theta,double phi,double *dzeta,double *gamma, double Z);
85 double integ_lv(float *lv,float *theta);
86
87 void printdefaults();
88 void check_sun_position();
89 void computesky();
90 void printhead(int ac, char** av);
91 void userror(char* msg);
92 void printsky();
93
94 FILE * frlibopen(char* fname);
95
96 /* astronomy and geometry*/
97 double get_eccentricity();
98 double air_mass();
99
100 double solar_sunset();
101 double solar_sunrise();
102 double stadj();
103 int jdate(int month, int day);
104
105
106
107 /* sun calculation constants */
108 extern double s_latitude;
109 extern double s_longitude;
110 extern double s_meridian;
111
112 const double AU = 149597890E3;
113 const double solar_constant_e = 1367; /* solar constant W/m^2 */
114 const double solar_constant_l = 127.5; /* solar constant klux */
115
116 const double half_sun_angle = 0.2665;
117 const double half_direct_angle = 2.85;
118
119 const double skyclearinf = 1.0; /* limitations for the variation of the Perez parameters */
120 const double skyclearsup = 12.1;
121 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 double skyclearness = 0;
136 double skybrightness = 0;
137 double solarradiance;
138 double diffuseilluminance, directilluminance, diffuseirradiance, directirradiance, globalirradiance;
139 double sunzenith, daynumber, atm_preci_water=2;
140
141 /*double sunaltitude_border = 0;*/
142 double diffnormalization = 0;
143 double dirnormalization = 0;
144 double *c_perez;
145
146 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
150 int suppress_warnings=0;
151
152 /* default values */
153 int cloudy = 0; /* 1=standard, 2=uniform */
154 int dosun = 1;
155 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 double groundbr = 0;
163 double F2;
164 double solarbr = 0.0;
165 int u_solar = 0; /* -1=irradiance, 1=radiance */
166 float timeinterval = 0;
167
168 char *progname;
169 char errmsg[128];
170
171
172
173
174 int main(int argc, char** argv)
175 {
176 int i;
177
178 progname = argv[0];
179 if (argc == 2 && !strcmp(argv[1], "-defaults")) {
180 printdefaults();
181 return 0;
182 }
183 if (argc < 4)
184 userror("arg count");
185 if (!strcmp(argv[1], "-ang")) {
186 altitude = atof(argv[2]) * (M_PI/180);
187 azimuth = atof(argv[3]) * (M_PI/180);
188 month = 0;
189 } else {
190 month = atoi(argv[1]);
191 if (month < 1 || month > 12)
192 userror("bad month");
193 day = atoi(argv[2]);
194 if (day < 1 || day > 31)
195 userror("bad day");
196 hour = atof(argv[3]);
197 if (hour < 0 || hour >= 24)
198 userror("bad hour");
199 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 case 'w':
220 suppress_warnings = 1;
221 break;
222 case 'b':
223 zenithbr = atof(argv[++i]);
224 break;
225 case 'g':
226 gprefl = atof(argv[++i]);
227 break;
228 case 'a':
229 s_latitude = atof(argv[++i]) * (M_PI/180);
230 break;
231 case 'o':
232 s_longitude = atof(argv[++i]) * (M_PI/180);
233 break;
234 case 'm':
235 s_meridian = atof(argv[++i]) * (M_PI/180);
236 break;
237
238 case 'O':
239 output = atof(argv[++i]); /*define the unit of the output of the program :
240 sky and sun luminance/radiance (0==W visible, 1==W solar radiation, 2==lm) */
241 break;
242
243 case 'P':
244 input = 0; /* Perez parameters: epsilon, delta */
245 skyclearness = atof(argv[++i]);
246 skybrightness = atof(argv[++i]);
247 break;
248
249 case 'W': /* direct normal Irradiance [W/m^2] */
250 input = 1; /* diffuse horizontal Irrad. [W/m^2] */
251 directirradiance = atof(argv[++i]);
252 diffuseirradiance = atof(argv[++i]);
253 break;
254
255 case 'L': /* direct normal Illuminance [Lux] */
256 input = 2; /* diffuse horizontal Ill. [Lux] */
257 directilluminance = atof(argv[++i]);
258 diffuseilluminance = atof(argv[++i]);
259 break;
260
261 case 'G': /* direct horizontal Irradiance [W/m^2] */
262 input = 3; /* diffuse horizontal Irrad. [W/m^2] */
263 directirradiance = atof(argv[++i]);
264 diffuseirradiance = atof(argv[++i]);
265 break;
266
267 case 'E': /* Erbs model based on the */
268 input = 4; /* global-horizontal irradiance [W/m^2] */
269 globalirradiance = atof(argv[++i]);
270 break;
271
272 /*
273 case 'l':
274 sunaltitude_border = atof(argv[++i]);
275 break;
276 */
277
278 case 'i':
279 timeinterval = atof(argv[++i]);
280 break;
281
282
283 default:
284 sprintf(errmsg, "unknown option: %s", argv[i]);
285 userror(errmsg);
286 }
287 else
288 userror("bad option");
289
290 if (fabs(s_meridian-s_longitude) > 30*M_PI/180)
291 fprintf(stderr,
292 "%s: warning: %.1f hours btwn. standard meridian and longitude\n",
293 progname, (s_longitude-s_meridian)*12/M_PI);
294
295
296 /* dynamic memory allocation for the pointers */
297
298 if ( (c_perez = calloc(5, sizeof(double))) == NULL )
299 {
300 fprintf(stderr,"Out of memory error in function main");
301 return 1;
302 }
303
304 printhead(argc, argv);
305 computesky();
306
307 if(*(c_perez+1)>0)
308 {
309 fprintf(stderr, "Warning: positive Perez parameter B (= %lf), printing error sky\n",*(c_perez+1));
310 print_error_sky();
311 exit(1);
312 }
313
314 printsky();
315 return 0;
316 }
317
318
319
320
321
322
323
324
325 void computesky()
326 {
327
328 int j;
329
330 float *lv_mod; /* 145 luminance values */
331 float *theta_o, *phi_o;
332 double dzeta, gamma;
333 double normfactor;
334 double erbs_s0, erbs_kt;
335
336
337 /* compute solar direction */
338
339 if (month) { /* from date and time */
340 int jd;
341 double sd, st;
342
343 jd = jdate(month, day); /* Julian date */
344 sd = sdec(jd); /* solar declination */
345 if (tsolar) /* solar time */
346 st = hour;
347 else
348 st = hour + stadj(jd);
349
350
351 if(st<solar_sunrise(month,day) || st>solar_sunset(month,day)) {
352 print_error_sky();
353 exit(1);
354 }
355
356
357 if(timeinterval) {
358
359 if(timeinterval<0) {
360 fprintf(stderr, "time interval negative\n");
361 exit(1);
362 }
363
364 if(fabs(solar_sunrise(month,day)-st)<timeinterval/60) {
365
366 fprintf(stderr, "Solar position corrected at %d %d %.3f\n",month,day,hour);
367 st= (st+timeinterval/120+solar_sunrise(month,day))/2;
368 }
369
370 if(fabs(solar_sunset(month,day)-st)<timeinterval/60) {
371 fprintf(stderr, "Solar position corrected at %d %d %.3f\n",month,day,hour);
372 st= (st-timeinterval/120+solar_sunset(month,day))/2;
373 }
374 }
375
376
377 altitude = salt(sd, st);
378 azimuth = sazi(sd, st);
379
380 daynumber = (double)jdate(month, day);
381
382 }
383
384
385
386
387 /* if loop for the -l option. W.Sprenger (01/2013) */
388 /*
389 if (altitude*180/M_PI < sunaltitude_border) {
390
391 if (suppress_warnings==0) {
392 fprintf(stderr, "Warning: sun altitude (%.3f degrees) below the border (%.3f degrees)\n",altitude*180/M_PI,sunaltitude_border);
393 }
394 print_error_sky();
395 exit(1);
396 }
397 */
398
399
400 if (!cloudy && altitude > 87.*M_PI/180.) {
401
402 if (suppress_warnings==0) {
403 fprintf(stderr,
404 "%s: warning - sun too close to zenith, reducing altitude to 87 degrees\n",
405 progname);
406 }
407 altitude = 87.*M_PI/180.;
408 }
409
410 sundir[0] = -sin(azimuth)*cos(altitude);
411 sundir[1] = -cos(azimuth)*cos(altitude);
412 sundir[2] = sin(altitude);
413
414
415 /* calculation for the new functions */
416 sunzenith = 90 - altitude*180/M_PI;
417
418
419
420 /* compute the inputs for the calculation of the light distribution over the sky*/
421 if (input==0) /* P */
422 {
423 check_parametrization();
424 diffuseirradiance = diffuse_irradiance_from_sky_brightness(); /*diffuse horizontal irradiance*/
425 directirradiance = direct_irradiance_from_sky_clearness();
426 check_irradiances();
427
428 if (output==0 || output==2)
429 {
430 diffuseilluminance = diffuseirradiance*glob_h_diffuse_effi_PEREZ();/*diffuse horizontal illuminance*/
431 directilluminance = directirradiance*direct_n_effi_PEREZ();
432 check_illuminances();
433 }
434 }
435
436
437 else if (input==1) /* W */
438 {
439 check_irradiances();
440 skybrightness = sky_brightness();
441 skyclearness = sky_clearness();
442 check_parametrization();
443
444 if (output==0 || output==2)
445 {
446 diffuseilluminance = diffuseirradiance*glob_h_diffuse_effi_PEREZ();/*diffuse horizontal illuminance*/
447 directilluminance = directirradiance*direct_n_effi_PEREZ();
448 check_illuminances();
449 }
450
451 }
452
453
454 else if (input==2) /* L */
455 {
456 check_illuminances();
457 illu_to_irra_index();
458 check_parametrization();
459 }
460
461
462 else if (input==3) /* G */
463 {
464 if (altitude<=0)
465 {
466 if (suppress_warnings==0)
467 fprintf(stderr, "Warning: solar zenith angle larger than 90 degrees; using zero irradiance to proceed\n");
468 directirradiance = 0;
469 diffuseirradiance = 0;
470 } else {
471
472 directirradiance=directirradiance/sin(altitude);
473 }
474
475 check_irradiances();
476 skybrightness = sky_brightness();
477 skyclearness = sky_clearness();
478 check_parametrization();
479
480 if (output==0 || output==2)
481 {
482 diffuseilluminance = diffuseirradiance*glob_h_diffuse_effi_PEREZ();/*diffuse horizontal illuminance*/
483 directilluminance = directirradiance*direct_n_effi_PEREZ();
484 check_illuminances();
485 }
486
487 }
488
489
490 else if (input==4) /* E */ /* Implementation of the Erbs model. W.Sprenger (04/13) */
491 {
492
493 if (altitude<=0)
494 {
495 if (suppress_warnings==0 && globalirradiance > 50)
496 fprintf(stderr, "Warning: global irradiance higher than 50 W/m^2 while the sun altitude is lower than zero\n");
497 globalirradiance = 0; diffuseirradiance = 0; directirradiance = 0;
498
499 } else {
500
501 erbs_s0 = solar_constant_e*get_eccentricity()*sin(altitude);
502
503 if (globalirradiance>erbs_s0)
504 {
505 if (suppress_warnings==0)
506 fprintf(stderr, "Warning: global irradiance is higher than the time-dependent solar constant s0\n");
507
508 globalirradiance=erbs_s0*0.999;
509 }
510
511 erbs_kt=globalirradiance/erbs_s0;
512
513 if (erbs_kt<=0.22) diffuseirradiance=globalirradiance*(1-0.09*erbs_kt);
514 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));
515 else if (erbs_kt<1) diffuseirradiance=globalirradiance*(0.165);
516
517 directirradiance=globalirradiance-diffuseirradiance;
518
519 printf("# erbs_s0, erbs_kt, irr_dir_h, irr_diff: %.3f %.3f %.3f %.3f\n", erbs_s0, erbs_kt, directirradiance, diffuseirradiance);
520 printf("# WARNING: the -E option is only recommended for a rough estimation!");
521
522 directirradiance=directirradiance/sin(altitude);
523
524 }
525
526 check_irradiances();
527 skybrightness = sky_brightness();
528 skyclearness = sky_clearness();
529 check_parametrization();
530
531 if (output==0 || output==2)
532 {
533 diffuseilluminance = diffuseirradiance*glob_h_diffuse_effi_PEREZ();/*diffuse horizontal illuminance*/
534 directilluminance = directirradiance*direct_n_effi_PEREZ();
535 check_illuminances();
536 }
537
538 }
539
540
541
542
543 else {fprintf(stderr,"error at the input arguments"); exit(1);}
544
545
546
547 /* normalization factor for the relative sky luminance distribution, diffuse part*/
548
549 if ( (lv_mod = malloc(145*sizeof(float))) == NULL)
550 {
551 fprintf(stderr,"Out of memory in function main");
552 exit(1);
553 }
554
555 /* read the angles */
556 theta_o = defangle_theta;
557 phi_o = defangle_phi;
558
559
560 /* parameters for the perez model */
561 coeff_lum_perez(radians(sunzenith), skyclearness, skybrightness, coeff_perez);
562
563
564
565
566
567 /*calculation of the modelled luminance */
568 for (j=0;j<145;j++)
569 {
570 theta_phi_to_dzeta_gamma(radians(*(theta_o+j)),radians(*(phi_o+j)),&dzeta,&gamma,radians(sunzenith));
571
572 *(lv_mod+j) = calc_rel_lum_perez(dzeta,gamma,radians(sunzenith),skyclearness,skybrightness,coeff_perez);
573
574 /* fprintf(stderr,"theta, phi, lv_mod %f\t %f\t %f\n", *(theta_o+j),*(phi_o+j),*(lv_mod+j)); */
575 }
576
577 /* integration of luminance for the normalization factor, diffuse part of the sky*/
578
579 diffnormalization = integ_lv(lv_mod, theta_o);
580
581
582
583 /*normalization coefficient in lumen or in watt*/
584 if (output==0)
585 {
586 diffnormalization = diffuseilluminance/diffnormalization/WHTEFFICACY;
587 }
588 else if (output==1)
589 {
590 diffnormalization = diffuseirradiance/diffnormalization;
591 }
592 else if (output==2)
593 {
594 diffnormalization = diffuseilluminance/diffnormalization;
595 }
596
597 else {fprintf(stderr,"Wrong output specification.\n"); exit(1);}
598
599
600
601
602 /* calculation for the solar source */
603 if (output==0)
604 solarradiance = directilluminance/(2*M_PI*(1-cos(half_sun_angle*M_PI/180)))/WHTEFFICACY;
605
606 else if (output==1)
607 solarradiance = directirradiance/(2*M_PI*(1-cos(half_sun_angle*M_PI/180)));
608
609 else
610 solarradiance = directilluminance/(2*M_PI*(1-cos(half_sun_angle*M_PI/180)));
611
612
613
614
615 /* Compute the ground radiance */
616 zenithbr=calc_rel_lum_perez(0.0,radians(sunzenith),radians(sunzenith),skyclearness,skybrightness,coeff_perez);
617 zenithbr*=diffnormalization;
618
619 if (skyclearness==1)
620 normfactor = 0.777778;
621
622 if (skyclearness>=6)
623 {
624 F2 = 0.274*(0.91 + 10.0*exp(-3.0*(M_PI/2.0-altitude)) + 0.45*sundir[2]*sundir[2]);
625 normfactor = normsc()/F2/M_PI;
626 }
627
628 if ( (skyclearness>1) && (skyclearness<6) )
629 {
630 S_INTER=1;
631 F2 = (2.739 + .9891*sin(.3119+2.6*altitude)) * exp(-(M_PI/2.0-altitude)*(.4441+1.48*altitude));
632 normfactor = normsc()/F2/M_PI;
633 }
634
635 groundbr = zenithbr*normfactor;
636
637 if (dosun&&(skyclearness>1))
638 groundbr += 6.8e-5/M_PI*solarradiance*sundir[2];
639
640 groundbr *= gprefl;
641
642
643
644 return;
645 }
646
647
648
649
650 void print_error_sky()
651 {
652 sundir[0] = -sin(azimuth)*cos(altitude);
653 sundir[1] = -cos(azimuth)*cos(altitude);
654 sundir[2] = sin(altitude);
655
656 printf("\nvoid brightfunc skyfunc\n");
657 printf("2 skybright perezlum.cal\n");
658 printf("0\n");
659 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]);
660 }
661
662
663
664
665
666
667
668 double solar_sunset(int month,int day)
669 {
670 float W;
671 extern double s_latitude;
672 W=-1*(tan(s_latitude)*tan(sdec(jdate(month, day))));
673 return(12+(M_PI/2 - atan2(W,sqrt(1-W*W)))*180/(M_PI*15));
674 }
675
676
677 double solar_sunrise(int month,int day)
678 {
679 float W;
680 extern double s_latitude;
681 W=-1*(tan(s_latitude)*tan(sdec(jdate(month, day))));
682 return(12-(M_PI/2 - atan2(W,sqrt(1-W*W)))*180/(M_PI*15));
683 }
684
685
686
687
688
689
690
691
692
693
694
695 void printsky() /* print out sky */
696 {
697 if (dosun&&(skyclearness>1))
698 {
699 printf("\nvoid light solar\n");
700 printf("0\n0\n");
701 printf("3 %.3e %.3e %.3e\n", solarradiance, solarradiance, solarradiance);
702 printf("\nsolar source sun\n");
703 printf("0\n0\n");
704 printf("4 %f %f %f %f\n", sundir[0], sundir[1], sundir[2], 2*half_sun_angle);
705 } else if (dosun) {
706 printf("\nvoid light solar\n");
707 printf("0\n0\n");
708 printf("3 0.0 0.0 0.0\n");
709 printf("\nsolar source sun\n");
710 printf("0\n0\n");
711 printf("4 %f %f %f %f\n", sundir[0], sundir[1], sundir[2], 2*half_sun_angle);
712 }
713
714
715 printf("\nvoid brightfunc skyfunc\n");
716 printf("2 skybright perezlum.cal\n");
717 printf("0\n");
718 printf("10 %.3e %.3e %lf %lf %lf %lf %lf %f %f %f \n", diffnormalization, groundbr,
719 *(c_perez+0),*(c_perez+1),*(c_perez+2),*(c_perez+3),*(c_perez+4),
720 sundir[0], sundir[1], sundir[2]);
721
722 }
723
724
725 void printdefaults() /* print default values */
726 {
727 printf("-g %f\t\t\t# Ground plane reflectance\n", gprefl);
728 if (zenithbr > 0.0)
729 printf("-b %f\t\t\t# Zenith radiance (watts/ster/m^2\n", zenithbr);
730 else
731 printf("-t %f\t\t\t# Atmospheric betaturbidity\n", betaturbidity);
732 printf("-a %f\t\t\t# Site latitude (degrees)\n", s_latitude*(180/M_PI));
733 printf("-o %f\t\t\t# Site longitude (degrees)\n", s_longitude*(180/M_PI));
734 printf("-m %f\t\t\t# Standard meridian (degrees)\n", s_meridian*(180/M_PI));
735 }
736
737
738 void userror(char* msg) /* print usage error and quit */
739 {
740 if (msg != NULL)
741 fprintf(stderr, "%s: Use error - %s\n\n", progname, msg);
742 fprintf(stderr, "Usage: %s month day hour [...]\n", progname);
743 fprintf(stderr, " or: %s -ang altitude azimuth [...]\n", progname);
744 fprintf(stderr, " followed by: -P epsilon delta [options]\n");
745 fprintf(stderr, " or: [-W|-L|-G] direct_value diffuse_value [options]\n");
746 fprintf(stderr, " or: -E global_irradiance [options]\n\n");
747 fprintf(stderr, " Description:\n");
748 fprintf(stderr, " -P epsilon delta (these are the Perez parameters) \n");
749 fprintf(stderr, " -W direct-normal-irradiance diffuse-horizontal-irradiance (W/m^2)\n");
750 fprintf(stderr, " -L direct-normal-illuminance diffuse-horizontal-illuminance (lux)\n");
751 fprintf(stderr, " -G direct-horizontal-irradiance diffuse-horizontal-irradiance (W/m^2)\n");
752 fprintf(stderr, " -E global-horizontal-irradiance (W/m^2)\n\n");
753 fprintf(stderr, " Output specification with option:\n");
754 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");
755 fprintf(stderr, " gendaylit version 2.3 (2013/08/08) \n\n");
756 exit(1);
757 }
758
759
760
761 double normsc() /* compute normalization factor (E0*F2/L0) */
762 {
763 static double nfc[2][5] = {
764 /* clear sky approx. */
765 {2.766521, 0.547665, -0.369832, 0.009237, 0.059229},
766 /* intermediate sky approx. */
767 {3.5556, -2.7152, -1.3081, 1.0660, 0.60227},
768 };
769 register double *nf;
770 double x, nsc;
771 register int i;
772 /* polynomial approximation */
773 nf = nfc[S_INTER];
774 x = (altitude - M_PI/4.0)/(M_PI/4.0);
775 nsc = nf[i=4];
776 while (i--)
777 nsc = nsc*x + nf[i];
778
779 return(nsc);
780 }
781
782
783
784 void printhead(int ac, char** av) /* print command header */
785 {
786 putchar('#');
787 while (ac--) {
788 putchar(' ');
789 fputs(*av++, stdout);
790 }
791 putchar('\n');
792 }
793
794
795
796
797 /* Perez models */
798
799 /* Perez global horizontal luminous efficacy model */
800 double glob_h_effi_PEREZ()
801 {
802
803 double value;
804 double category_bounds[10], a[10], b[10], c[10], d[10];
805 int category_total_number, category_number, i;
806
807 check_parametrization();
808
809
810 /*if ((skyclearness<skyclearinf || skyclearness>skyclearsup || skybrightness<skybriginf || skybrightness>skybrigsup) && suppress_warnings==0)
811 fprintf(stderr, "Warning: skyclearness or skybrightness out of range in function glob_h_effi_PEREZ \n"); */
812
813
814 /* initialize category bounds (clearness index bounds) */
815
816 category_total_number = 8;
817
818 category_bounds[1] = 1;
819 category_bounds[2] = 1.065;
820 category_bounds[3] = 1.230;
821 category_bounds[4] = 1.500;
822 category_bounds[5] = 1.950;
823 category_bounds[6] = 2.800;
824 category_bounds[7] = 4.500;
825 category_bounds[8] = 6.200;
826 category_bounds[9] = 12.01;
827
828
829 /* initialize model coefficients */
830 a[1] = 96.63;
831 a[2] = 107.54;
832 a[3] = 98.73;
833 a[4] = 92.72;
834 a[5] = 86.73;
835 a[6] = 88.34;
836 a[7] = 78.63;
837 a[8] = 99.65;
838
839 b[1] = -0.47;
840 b[2] = 0.79;
841 b[3] = 0.70;
842 b[4] = 0.56;
843 b[5] = 0.98;
844 b[6] = 1.39;
845 b[7] = 1.47;
846 b[8] = 1.86;
847
848 c[1] = 11.50;
849 c[2] = 1.79;
850 c[3] = 4.40;
851 c[4] = 8.36;
852 c[5] = 7.10;
853 c[6] = 6.06;
854 c[7] = 4.93;
855 c[8] = -4.46;
856
857 d[1] = -9.16;
858 d[2] = -1.19;
859 d[3] = -6.95;
860 d[4] = -8.31;
861 d[5] = -10.94;
862 d[6] = -7.60;
863 d[7] = -11.37;
864 d[8] = -3.15;
865
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 c[category_number]*cos(sunzenith*M_PI/180) + d[category_number]*log(skybrightness);
877
878 return(value);
879 }
880
881
882 /* global horizontal diffuse efficacy model, according to PEREZ */
883 double glob_h_diffuse_effi_PEREZ()
884 {
885 double value;
886 double category_bounds[10], a[10], b[10], c[10], d[10];
887 int category_total_number, category_number, i;
888
889
890
891
892 check_parametrization();
893
894
895 /*if ((skyclearness<skyclearinf || skyclearness>skyclearsup || skybrightness<skybriginf || skybrightness>skybrigsup) && suppress_warnings==0)
896 fprintf(stderr, "Warning: skyclearness or skybrightness out of range in function glob_h_diffuse_PEREZ \n"); */
897
898
899
900 /* initialize category bounds (clearness index bounds) */
901
902 category_total_number = 8;
903
904 //XXX: category_bounds > 0.1
905 category_bounds[1] = 1;
906 category_bounds[2] = 1.065;
907 category_bounds[3] = 1.230;
908 category_bounds[4] = 1.500;
909 category_bounds[5] = 1.950;
910 category_bounds[6] = 2.800;
911 category_bounds[7] = 4.500;
912 category_bounds[8] = 6.200;
913 category_bounds[9] = 12.01;
914
915
916 /* initialize model coefficients */
917 a[1] = 97.24;
918 a[2] = 107.22;
919 a[3] = 104.97;
920 a[4] = 102.39;
921 a[5] = 100.71;
922 a[6] = 106.42;
923 a[7] = 141.88;
924 a[8] = 152.23;
925
926 b[1] = -0.46;
927 b[2] = 1.15;
928 b[3] = 2.96;
929 b[4] = 5.59;
930 b[5] = 5.94;
931 b[6] = 3.83;
932 b[7] = 1.90;
933 b[8] = 0.35;
934
935 c[1] = 12.00;
936 c[2] = 0.59;
937 c[3] = -5.53;
938 c[4] = -13.95;
939 c[5] = -22.75;
940 c[6] = -36.15;
941 c[7] = -53.24;
942 c[8] = -45.27;
943
944 d[1] = -8.91;
945 d[2] = -3.95;
946 d[3] = -8.77;
947 d[4] = -13.90;
948 d[5] = -23.74;
949 d[6] = -28.83;
950 d[7] = -14.03;
951 d[8] = -7.98;
952
953
954
955
956 category_number = -1;
957 for (i=1; i<=category_total_number; i++)
958 {
959 if ( (skyclearness >= category_bounds[i]) && (skyclearness < category_bounds[i+1]) )
960 category_number = i;
961 }
962
963 if (category_number == -1) {
964 if (suppress_warnings==0)
965 fprintf(stderr, "ERROR: Model parameters out of range, skyclearness = %lf \n", skyclearness);
966 print_error_sky();
967 exit(1);
968 }
969
970
971 value = a[category_number] + b[category_number]*atm_preci_water + c[category_number]*cos(sunzenith*M_PI/180) +
972 d[category_number]*log(skybrightness);
973
974 return(value);
975
976 }
977
978
979
980 /* direct normal efficacy model, according to PEREZ */
981
982 double direct_n_effi_PEREZ()
983
984 {
985 double value;
986 double category_bounds[10], a[10], b[10], c[10], d[10];
987 int category_total_number, category_number, i;
988
989
990 if ((skyclearness<skyclearinf || skyclearness>skyclearsup || skybrightness<skybriginf || skybrightness>skybrigsup) && suppress_warnings==0)
991 fprintf(stderr, "Warning: skyclearness or skybrightness out of range in function direct_n_effi_PEREZ \n");
992
993
994 /* initialize category bounds (clearness index bounds) */
995
996 category_total_number = 8;
997
998 category_bounds[1] = 1;
999 category_bounds[2] = 1.065;
1000 category_bounds[3] = 1.230;
1001 category_bounds[4] = 1.500;
1002 category_bounds[5] = 1.950;
1003 category_bounds[6] = 2.800;
1004 category_bounds[7] = 4.500;
1005 category_bounds[8] = 6.200;
1006 category_bounds[9] = 12.1;
1007
1008
1009 /* initialize model coefficients */
1010 a[1] = 57.20;
1011 a[2] = 98.99;
1012 a[3] = 109.83;
1013 a[4] = 110.34;
1014 a[5] = 106.36;
1015 a[6] = 107.19;
1016 a[7] = 105.75;
1017 a[8] = 101.18;
1018
1019 b[1] = -4.55;
1020 b[2] = -3.46;
1021 b[3] = -4.90;
1022 b[4] = -5.84;
1023 b[5] = -3.97;
1024 b[6] = -1.25;
1025 b[7] = 0.77;
1026 b[8] = 1.58;
1027
1028 c[1] = -2.98;
1029 c[2] = -1.21;
1030 c[3] = -1.71;
1031 c[4] = -1.99;
1032 c[5] = -1.75;
1033 c[6] = -1.51;
1034 c[7] = -1.26;
1035 c[8] = -1.10;
1036
1037 d[1] = 117.12;
1038 d[2] = 12.38;
1039 d[3] = -8.81;
1040 d[4] = -4.56;
1041 d[5] = -6.16;
1042 d[6] = -26.73;
1043 d[7] = -34.44;
1044 d[8] = -8.29;
1045
1046
1047
1048 for (i=1; i<=category_total_number; i++)
1049 {
1050 if ( (skyclearness >= category_bounds[i]) && (skyclearness < category_bounds[i+1]) )
1051 category_number = i;
1052 }
1053
1054 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;
1055
1056 if (value < 0) value = 0;
1057
1058 return(value);
1059 }
1060
1061
1062 /*check the range of epsilon and delta indexes of the perez parametrization*/
1063 void check_parametrization()
1064 {
1065 if (skyclearness<skyclearinf || skyclearness>skyclearsup || skybrightness<skybriginf || skybrightness>skybrigsup)
1066 {
1067
1068 /* limit sky clearness or sky brightness, 2009 11 13 by J. Wienold */
1069 if (skyclearness<skyclearinf){
1070 if (suppress_warnings==0)
1071 /* fprintf(stderr,"Range warning: sky clearness too low (%lf)\n", skyclearness); */
1072 skyclearness=skyclearinf;
1073 }
1074 if (skyclearness>skyclearsup){
1075 if (suppress_warnings==0)
1076 /* fprintf(stderr,"Range warning: sky clearness too high (%lf)\n", skyclearness); */
1077 skyclearness=skyclearsup-0.1;
1078 }
1079 if (skybrightness<skybriginf){
1080 if (suppress_warnings==0)
1081 /* fprintf(stderr,"Range warning: sky brightness too low (%lf)\n", skybrightness); */
1082 skybrightness=skybriginf;
1083 }
1084 if (skybrightness>skybrigsup){
1085 if (suppress_warnings==0)
1086 /* fprintf(stderr,"Range warning: sky brightness too high (%lf)\n", skybrightness); */
1087 skybrightness=skybrigsup;
1088 }
1089
1090 return; }
1091 else return;
1092 }
1093
1094
1095 /* validity of the direct and diffuse components */
1096 void check_illuminances()
1097 {
1098 if (directilluminance < 0) {
1099 fprintf(stderr,"WARNING: direct illuminance < 0. Using 0.0\n");
1100 directilluminance = 0.0;
1101 }
1102 if (diffuseilluminance < 0) {
1103 fprintf(stderr,"WARNING: diffuse illuminance < 0. Using 0.0\n");
1104 diffuseilluminance = 0.0;
1105 }
1106 if (directilluminance > solar_constant_l*1000.0) {
1107 fprintf(stderr,"ERROR: direct illuminance exceeds solar constant\n");
1108 exit(1);
1109 }
1110 }
1111
1112
1113 void check_irradiances()
1114 {
1115 if (directirradiance < 0) {
1116 fprintf(stderr,"WARNING: direct irradiance < 0. Using 0.0\n");
1117 directirradiance = 0.0;
1118 }
1119 if (diffuseirradiance < 0) {
1120 fprintf(stderr,"WARNING: diffuse irradiance < 0. Using 0.0\n");
1121 diffuseirradiance = 0.0;
1122 }
1123 if (directirradiance > solar_constant_e) {
1124 fprintf(stderr,"ERROR: direct irradiance exceeds solar constant\n");
1125 exit(1);
1126 }
1127 }
1128
1129
1130
1131 /* Perez sky's brightness */
1132 double sky_brightness()
1133 {
1134 double value;
1135
1136 value = diffuseirradiance * air_mass() / ( solar_constant_e*get_eccentricity());
1137
1138 return(value);
1139 }
1140
1141
1142 /* Perez sky's clearness */
1143 double sky_clearness()
1144 {
1145 double value;
1146
1147 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) ;
1148
1149 return(value);
1150 }
1151
1152
1153
1154 /* diffus horizontal irradiance from Perez sky's brightness */
1155 double diffuse_irradiance_from_sky_brightness()
1156 {
1157 double value;
1158
1159 value = skybrightness / air_mass() * ( solar_constant_e*get_eccentricity());
1160
1161 return(value);
1162 }
1163
1164
1165 /* direct normal irradiance from Perez sky's clearness */
1166 double direct_irradiance_from_sky_clearness()
1167 {
1168 double value;
1169
1170 value = diffuse_irradiance_from_sky_brightness();
1171 value = value * ( (skyclearness-1) * (1+1.041*sunzenith*M_PI/180*sunzenith*M_PI/180*sunzenith*M_PI/180) );
1172
1173 return(value);
1174 }
1175
1176
1177
1178
1179 void illu_to_irra_index()
1180 {
1181 double test1=0.1, test2=0.1, d_eff;
1182 int counter=0;
1183
1184 diffuseirradiance = diffuseilluminance*solar_constant_e/(solar_constant_l*1000);
1185 directirradiance = directilluminance*solar_constant_e/(solar_constant_l*1000);
1186 skyclearness = sky_clearness();
1187 skybrightness = sky_brightness();
1188 check_parametrization();
1189
1190
1191 while ( ((fabs(diffuseirradiance-test1)>10) || (fabs(directirradiance-test2)>10)
1192 || (!(skyclearness<skyclearinf || skyclearness>skyclearsup))
1193 || (!(skybrightness<skybriginf || skybrightness>skybrigsup)) )
1194 && !(counter==9) )
1195 {
1196
1197 test1=diffuseirradiance;
1198 test2=directirradiance;
1199 counter++;
1200
1201 diffuseirradiance = diffuseilluminance/glob_h_diffuse_effi_PEREZ();
1202 d_eff = direct_n_effi_PEREZ();
1203
1204
1205 if (d_eff < 0.1)
1206 directirradiance = 0;
1207 else
1208 directirradiance = directilluminance/d_eff;
1209
1210 skybrightness = sky_brightness();
1211 skyclearness = sky_clearness();
1212 check_parametrization();
1213
1214 /*fprintf(stderr,"skyclearness = %lf, skybrightness = %lf, directirradiance = %lf, diffuseirradiance = %lf\n",skyclearness, skybrightness, directirradiance, diffuseirradiance);*/
1215
1216 }
1217
1218
1219 return;
1220 }
1221
1222 static int get_numlin(float epsilon)
1223 {
1224 if (epsilon < 1.065)
1225 return 0;
1226 else if (epsilon < 1.230)
1227 return 1;
1228 else if (epsilon < 1.500)
1229 return 2;
1230 else if (epsilon < 1.950)
1231 return 3;
1232 else if (epsilon < 2.800)
1233 return 4;
1234 else if (epsilon < 4.500)
1235 return 5;
1236 else if (epsilon < 6.200)
1237 return 6;
1238 return 7;
1239 }
1240
1241 /* sky luminance perez model */
1242 double calc_rel_lum_perez(double dzeta,double gamma,double Z,double epsilon,double Delta,float coeff_perez[])
1243 {
1244
1245 float x[5][4];
1246 int i,j,num_lin;
1247 double c_perez[5];
1248
1249 if ( (epsilon < skyclearinf) || (epsilon >= skyclearsup) )
1250 {
1251 fprintf(stderr,"Epsilon out of range in function calc_rel_lum_perez!\n");
1252 exit(1);
1253 }
1254
1255 /* correction de modele de Perez solar energy ...*/
1256 if ( (epsilon > 1.065) && (epsilon < 2.8) )
1257 {
1258 if ( Delta < 0.2 ) Delta = 0.2;
1259 }
1260
1261
1262 num_lin = get_numlin(epsilon);
1263
1264 for (i=0;i<5;i++)
1265 for (j=0;j<4;j++)
1266 {
1267 x[i][j] = *(coeff_perez + 20*num_lin + 4*i +j);
1268 /* fprintf(stderr,"x %d %d vaut %f\n",i,j,x[i][j]); */
1269 }
1270
1271
1272 if (num_lin)
1273 {
1274 for (i=0;i<5;i++)
1275 c_perez[i] = x[i][0] + x[i][1]*Z + Delta * (x[i][2] + x[i][3]*Z);
1276 }
1277 else
1278 {
1279 c_perez[0] = x[0][0] + x[0][1]*Z + Delta * (x[0][2] + x[0][3]*Z);
1280 c_perez[1] = x[1][0] + x[1][1]*Z + Delta * (x[1][2] + x[1][3]*Z);
1281 c_perez[4] = x[4][0] + x[4][1]*Z + Delta * (x[4][2] + x[4][3]*Z);
1282 c_perez[2] = exp( pow(Delta*(x[2][0]+x[2][1]*Z),x[2][2])) - x[2][3];
1283 c_perez[3] = -exp( Delta*(x[3][0]+x[3][1]*Z) )+x[3][2]+Delta*x[3][3];
1284 }
1285
1286
1287 return (1 + c_perez[0]*exp(c_perez[1]/cos(dzeta)) ) *
1288 (1 + c_perez[2]*exp(c_perez[3]*gamma) +
1289 c_perez[4]*cos(gamma)*cos(gamma) );
1290 }
1291
1292
1293
1294 /* coefficients for the sky luminance perez model */
1295 void coeff_lum_perez(double Z, double epsilon, double Delta, float coeff_perez[])
1296 {
1297 float x[5][4];
1298 int i,j,num_lin;
1299
1300 if ( (epsilon < skyclearinf) || (epsilon >= skyclearsup) )
1301 {
1302 fprintf(stderr,"Epsilon out of range in function calc_rel_lum_perez !\n");
1303 exit(1);
1304 }
1305
1306 /* correction du modele de Perez solar energy ...*/
1307 if ( (epsilon > 1.065) && (epsilon < 2.8) )
1308 {
1309 if ( Delta < 0.2 ) Delta = 0.2;
1310 }
1311
1312
1313 num_lin = get_numlin(epsilon);
1314
1315 /*fprintf(stderr,"numlin %d\n", num_lin);*/
1316
1317 for (i=0;i<5;i++)
1318 for (j=0;j<4;j++)
1319 {
1320 x[i][j] = *(coeff_perez + 20*num_lin + 4*i +j);
1321 /* printf("x %d %d vaut %f\n",i,j,x[i][j]); */
1322 }
1323
1324
1325 if (num_lin)
1326 {
1327 for (i=0;i<5;i++)
1328 *(c_perez+i) = x[i][0] + x[i][1]*Z + Delta * (x[i][2] + x[i][3]*Z);
1329
1330 }
1331 else
1332 {
1333 *(c_perez+0) = x[0][0] + x[0][1]*Z + Delta * (x[0][2] + x[0][3]*Z);
1334 *(c_perez+1) = x[1][0] + x[1][1]*Z + Delta * (x[1][2] + x[1][3]*Z);
1335 *(c_perez+4) = x[4][0] + x[4][1]*Z + Delta * (x[4][2] + x[4][3]*Z);
1336 *(c_perez+2) = exp( pow(Delta*(x[2][0]+x[2][1]*Z),x[2][2])) - x[2][3];
1337 *(c_perez+3) = -exp( Delta*(x[3][0]+x[3][1]*Z) )+x[3][2]+Delta*x[3][3];
1338
1339
1340 }
1341
1342
1343 return;
1344 }
1345
1346
1347
1348 /* degrees into radians */
1349 double radians(double degres)
1350 {
1351 return degres*M_PI/180.0;
1352 }
1353
1354
1355 /* radian into degrees */
1356 double degres(double radians)
1357 {
1358 return radians/M_PI*180.0;
1359 }
1360
1361
1362 /* calculation of the angles dzeta and gamma */
1363 void theta_phi_to_dzeta_gamma(double theta,double phi,double *dzeta,double *gamma, double Z)
1364 {
1365 *dzeta = theta; /* dzeta = phi */
1366 if ( (cos(Z)*cos(theta)+sin(Z)*sin(theta)*cos(phi)) > 1 && (cos(Z)*cos(theta)+sin(Z)*sin(theta)*cos(phi) < 1.1 ) )
1367 *gamma = 0;
1368 else if ( (cos(Z)*cos(theta)+sin(Z)*sin(theta)*cos(phi)) > 1.1 )
1369 {
1370 printf("error in calculation of gamma (angle between point and sun");
1371 exit(3);
1372 }
1373 else
1374 *gamma = acos(cos(Z)*cos(theta)+sin(Z)*sin(theta)*cos(phi));
1375 }
1376
1377
1378
1379 double integ_lv(float *lv,float *theta)
1380 {
1381 int i;
1382 double buffer=0.0;
1383
1384 for (i=0;i<145;i++)
1385 {
1386 buffer += (*(lv+i))*cos(radians(*(theta+i)));
1387 }
1388
1389 return buffer*2*M_PI/144;
1390 }
1391
1392
1393
1394 /* enter day number(double), return E0 = square(R0/R): eccentricity correction factor */
1395
1396 double get_eccentricity()
1397 {
1398 double day_angle;
1399 double E0;
1400
1401 day_angle = 2*M_PI*(daynumber - 1)/365;
1402 E0 = 1.00011+0.034221*cos(day_angle)+0.00128*sin(day_angle)+
1403 0.000719*cos(2*day_angle)+0.000077*sin(2*day_angle);
1404
1405 return (E0);
1406 }
1407
1408
1409 /* enter sunzenith angle (degrees) return relative air mass (double) */
1410 double air_mass()
1411 {
1412 double m;
1413 if (sunzenith>90)
1414 {
1415 fprintf(stderr, "Solar zenith angle larger than 90 degrees in function air_mass()\n");
1416 exit(1);
1417 }
1418 m = 1/( cos(sunzenith*M_PI/180)+0.15*exp( log(93.885-sunzenith)*(-1.253) ) );
1419 return(m);
1420 }
1421
1422
1423