| 1 | SUBROUTINE mucorr(npts,pdeclin, plat, pmu, pfract,phaut,prad) |
|---|
| 2 | IMPLICIT NONE |
|---|
| 3 | |
|---|
| 4 | c======================================================================= |
|---|
| 5 | c |
|---|
| 6 | c Calcul of equivalent solar angle and and fraction of day whithout |
|---|
| 7 | c diurnal cycle. |
|---|
| 8 | c |
|---|
| 9 | c parmeters : |
|---|
| 10 | c ----------- |
|---|
| 11 | c |
|---|
| 12 | c Input : |
|---|
| 13 | c ------- |
|---|
| 14 | c npts number of points |
|---|
| 15 | c pdeclin solar declinaison |
|---|
| 16 | c plat(npts) latitude |
|---|
| 17 | c phaut hauteur typique de l'atmosphere |
|---|
| 18 | c prad rayon planetaire |
|---|
| 19 | c |
|---|
| 20 | c Output : |
|---|
| 21 | c -------- |
|---|
| 22 | c pmu(npts) equivalent cosinus of the solar angle |
|---|
| 23 | c pfract(npts) fractionnal day |
|---|
| 24 | c |
|---|
| 25 | c======================================================================= |
|---|
| 26 | |
|---|
| 27 | c----------------------------------------------------------------------- |
|---|
| 28 | c |
|---|
| 29 | c 0. Declarations : |
|---|
| 30 | c ----------------- |
|---|
| 31 | |
|---|
| 32 | c Arguments : |
|---|
| 33 | c ----------- |
|---|
| 34 | INTEGER npts |
|---|
| 35 | REAL plat(npts),pmu(npts), pfract(npts) |
|---|
| 36 | REAL phaut,prad,pdeclin |
|---|
| 37 | c |
|---|
| 38 | c Local variables : |
|---|
| 39 | c ----------------- |
|---|
| 40 | INTEGER j |
|---|
| 41 | REAL pi |
|---|
| 42 | REAL z,cz,sz,tz,phi,cphi,sphi,tphi |
|---|
| 43 | REAL ap,a,t,b, tp |
|---|
| 44 | REAL alph |
|---|
| 45 | |
|---|
| 46 | c----------------------------------------------------------------------- |
|---|
| 47 | |
|---|
| 48 | pi = 4. * atan(1.0) |
|---|
| 49 | z = pdeclin |
|---|
| 50 | cz = cos (z) |
|---|
| 51 | sz = sin (z) |
|---|
| 52 | |
|---|
| 53 | DO 20 j = 1, npts |
|---|
| 54 | |
|---|
| 55 | phi = plat(j) |
|---|
| 56 | cphi = cos(phi) |
|---|
| 57 | if (cphi.le.1.e-9) cphi=1.e-9 |
|---|
| 58 | sphi = sin(phi) |
|---|
| 59 | tphi = sphi / cphi |
|---|
| 60 | b = cphi * cz |
|---|
| 61 | t = -tphi * sz / cz |
|---|
| 62 | a = 1.0 - t*t |
|---|
| 63 | ap = a |
|---|
| 64 | |
|---|
| 65 | IF(t.eq.0.) then |
|---|
| 66 | tp=0.5*pi |
|---|
| 67 | ELSE |
|---|
| 68 | IF (a.lt.0.) a = 0. |
|---|
| 69 | t = sqrt(a) / t |
|---|
| 70 | IF (t.lt.0.) then |
|---|
| 71 | tp = -atan (-t) + pi |
|---|
| 72 | ELSE |
|---|
| 73 | tp = atan(t) |
|---|
| 74 | ENDIF |
|---|
| 75 | ENDIF |
|---|
| 76 | t = tp |
|---|
| 77 | |
|---|
| 78 | pmu(j) = (sphi*sz*t) / pi + b*sin(t)/pi |
|---|
| 79 | pfract(j) = t / pi |
|---|
| 80 | IF (ap .lt.0.) then |
|---|
| 81 | pmu(j) = sphi * sz |
|---|
| 82 | pfract(j) = 1.0 |
|---|
| 83 | ENDIF |
|---|
| 84 | IF (pmu(j).le.0.0) pmu(j) = 0.0 |
|---|
| 85 | pmu(j) = pmu(j) / pfract(j) |
|---|
| 86 | IF (pmu(j).eq.0.) pfract(j) = 0. |
|---|
| 87 | |
|---|
| 88 | 20 CONTINUE |
|---|
| 89 | |
|---|
| 90 | c----------------------------------------------------------------------- |
|---|
| 91 | c correction de rotondite: |
|---|
| 92 | c ------------------------ |
|---|
| 93 | |
|---|
| 94 | alph=phaut/prad |
|---|
| 95 | DO 30 j=1,npts |
|---|
| 96 | c !!!!!! |
|---|
| 97 | pmu(j)=sqrt(1224.*pmu(j)*pmu(j)+1.)/35. |
|---|
| 98 | c $ (sqrt(alph*alph*pmu(j)*pmu(j)+2.*alph+1.)-alph*pmu(j)) |
|---|
| 99 | 30 CONTINUE |
|---|
| 100 | |
|---|
| 101 | RETURN |
|---|
| 102 | END |
|---|
