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Last change
on this file since 374 was
135,
checked in by aslmd, 14 years ago
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CHANGEMENT ARBORESCENCE ETAPE 2 -- NON COMPLET
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File size:
2.1 KB
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| 1 | SUBROUTINE mufract(jjm,pdecli, plat, pmu, pfract) |
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| 2 | IMPLICIT NONE |
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| 3 | c |
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| 4 | c======================================================================= |
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| 5 | c |
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| 6 | c Calcul of equivalent solar angle and and fraction of day without |
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| 7 | c diurnal cycle. |
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| 8 | c |
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| 9 | c parmeters : |
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| 10 | c ----------- |
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| 11 | c |
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| 12 | c Input : |
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| 13 | c ------- |
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| 14 | c jjm number of points |
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| 15 | c pdecli solar declinaison |
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| 16 | c plat(jjm) latitude |
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| 17 | c |
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| 18 | c Output : |
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| 19 | c -------- |
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| 20 | c pmu(jjm) equivalent cosinus of the solar angle |
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| 21 | c pfract(jjm) fractionnal day |
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| 22 | c |
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| 23 | c |
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| 24 | c======================================================================= |
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| 25 | c |
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| 26 | c----------------------------------------------------------------------- |
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| 27 | c |
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| 28 | c 0. Declarations : |
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| 29 | c ----------------- |
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| 30 | c |
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| 31 | c Arguments : |
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| 32 | c ----------- |
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| 33 | |
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| 34 | INTEGER jjm |
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| 35 | REAL plat(jjm),pmu(jjm), pfract(jjm) |
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| 36 | REAL pdecli |
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| 37 | c |
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| 38 | c Local variables : |
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| 39 | c ----------------- |
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| 40 | |
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| 41 | INTEGER j |
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| 42 | REAL pi |
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| 43 | REAL z,cz,sz,tz,phi,cphi,sphi,tphi |
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| 44 | REAL ap,a,t,b |
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| 45 | c |
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| 46 | c======================================================================= |
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| 47 | c |
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| 48 | pi = 4. * atan(1.0) |
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| 49 | z = pdecli |
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| 50 | cz = cos (z*pi/180.) |
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| 51 | sz = sin (z*pi/180.) |
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| 52 | c |
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| 53 | DO 20 j = 1, jjm |
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| 54 | c |
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| 55 | phi = plat(j) |
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| 56 | cphi = cos(phi) |
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| 57 | if (cphi.le.1.e-9) cphi=1.e-9 |
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| 58 | sphi = sin(phi) |
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| 59 | tphi = sphi / cphi |
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| 60 | b = cphi * cz |
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| 61 | t = -tphi * sz / cz |
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| 62 | a = 1.0 - t*t |
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| 63 | ap = a |
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| 64 | IF(t.eq.0.) THEN |
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| 65 | t=0.5*pi |
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| 66 | ELSE |
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| 67 | IF (a.lt.0.) a = 0. |
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| 68 | t = sqrt(a) / t |
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| 69 | IF (t.lt.0.) THEN |
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| 70 | t = -atan (-t) + pi |
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| 71 | ELSE |
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| 72 | t = atan(t) |
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| 73 | ENDIF |
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| 74 | ENDIF |
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| 75 | pmu(j) = (sphi*sz*t) / pi + b*sin(t)/pi |
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| 76 | pfract(j) = t / pi |
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| 77 | IF (ap .lt.0.) THEN |
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| 78 | pmu(j) = sphi * sz |
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| 79 | pfract(j) = 1.0 |
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| 80 | ENDIF |
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| 81 | IF (pmu(j).le.0.0) pmu(j) = 0.0 |
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| 82 | pmu(j) = pmu(j) / pfract(j) |
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| 83 | IF (pmu(j).eq.0.) pfract(j) = 0. |
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| 84 | c |
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| 85 | 20 CONTINUE |
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| 86 | c |
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| 87 | RETURN |
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| 88 | END |
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| 89 | c |
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| 90 | c* end of mufract |
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| 91 | c======================================================================= |
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| 92 | c |
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