| 1 | PRO angle, glamu, gphiu, glamv, gphiv, glamf, gphif, gsinu, gsinv, gcosu, gcosv |
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| 2 | ;;;--------------------------------------------------------------------- |
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| 3 | ;;; |
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| 4 | ;;; ROUTINE angle |
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| 5 | ;;; ******************* |
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| 6 | ;;; |
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| 7 | ;;; Purpose : |
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| 8 | ;;; -------- |
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| 9 | ;;; Compute angles between grid lines and direction of the North |
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| 10 | ;;; |
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| 11 | ;; Method : |
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| 12 | ;; ------- |
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| 13 | ;; |
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| 14 | ;; Input : |
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| 15 | ;; ------ |
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| 16 | ;; common |
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| 17 | ;; /comcoh/ glamf, : longitudes and latitudes at F-points |
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| 18 | ;; gphif |
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| 19 | ;; |
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| 20 | ;; Output : |
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| 21 | ;; ------- |
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| 22 | ;; common |
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| 23 | ;; /comcoh/ gsinu,gcosu : sinus and cosinus of the angle |
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| 24 | ;; gsinv,gcosv between north-south direction |
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| 25 | ;; and the j-direction of the mesh |
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| 26 | ;; |
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| 27 | ;; Modifications: |
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| 28 | ;; -------------- |
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| 29 | ;; Original : 96-07 (O. Marti) |
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| 30 | ;; 98-06 (G. Madec) |
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| 31 | ;; 99-11 (A. Jouzeau) : Adaptation to IDL |
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| 32 | ;;---------------------------------------------------------------------- |
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| 33 | ;;---------------------------------------------------------------------- |
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| 34 | ; |
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| 35 | ;;;--------------------------------------------------------------------- |
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| 36 | ;;; OPA8, LODYC (1997) |
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| 37 | ;;;--------------------------------------------------------------------- |
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| 38 | ; |
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| 39 | ; I. Compute the cosinus and sinus |
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| 40 | ; ================================ |
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| 41 | ; |
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| 42 | ; ... north pole direction & modulous (at u-point) |
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| 43 | zxnpu = 0. - fsxspp( glamu, gphiu ) |
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| 44 | zynpu = 0. - fsyspp( glamu, gphiu ) |
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| 45 | znnpu = zxnpu*zxnpu + zynpu*zynpu |
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| 46 | ; |
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| 47 | ; ... north pole direction & modulous (at v-point) |
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| 48 | zxnpv = 0. - fsxspp( glamv, gphiv ) |
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| 49 | zynpv = 0. - fsyspp( glamv, gphiv ) |
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| 50 | znnpv = zxnpv*zxnpv + zynpv*zynpv |
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| 51 | ; |
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| 52 | ; ... j-direction: f-point segment direction (u-point) |
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| 53 | zxffu= fsxspp( glamf, gphif ) - fsxspp( shift(glamf, 0, 1), shift(gphif, 0, 1) ) |
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| 54 | zyffu= fsyspp( glamf, gphif ) - fsyspp( shift(glamf, 0, 1), shift(gphif, 0, 1) ) |
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| 55 | zmnpfu= sqrt ( znnpu * ( zxffu*zxffu + zyffu*zyffu ) ) |
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| 56 | |
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| 57 | |
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| 58 | ; |
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| 59 | ; ... i-direction: f-point segment direction (v-point) |
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| 60 | zxffv= fsxspp( glamf, gphif ) - fsxspp( shift(glamf, 1, 0), shift(gphif, 1, 0) ) |
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| 61 | zyffv= fsyspp( glamf, gphif ) - fsyspp( shift(glamf, 1, 0), shift(gphif, 1, 0) ) |
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| 62 | zmnpfv= sqrt ( znnpv * ( zxffv*zxffv + zyffv*zyffv ) ) |
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| 63 | |
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| 64 | ; |
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| 65 | ; ... cosinus and sinus using scalar and vectorial products |
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| 66 | gsinu = ( zxnpu*zyffu - zynpu*zxffu ) / zmnpfu |
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| 67 | gcosu = ( zxnpu*zxffu + zynpu*zyffu ) / zmnpfu |
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| 68 | |
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| 69 | |
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| 70 | ; |
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| 71 | ; ... cosinus and sinus using scalar and vectorial products |
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| 72 | ; (caution, rotation of 90 degres) |
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| 73 | gsinv = ( zxnpv*zxffv + zynpv*zyffv ) / zmnpfv |
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| 74 | gcosv =-( zxnpv*zyffv - zynpv*zxffv ) / zmnpfv |
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| 75 | |
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| 76 | |
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| 77 | ; |
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| 78 | ; |
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| 79 | ; II. Geographic mesh |
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| 80 | ; =================== |
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| 81 | ; |
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| 82 | ; |
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| 83 | ind = where(abs(glamf-shift(glamf, 0, 1)) LT 1.e-8) |
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| 84 | gsinu(ind) = 0.d |
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| 85 | gcosu(ind) = 1.d |
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| 86 | ; |
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| 87 | ind = where(abs(gphif-shift(gphif, 1, 0)) LT 1.e-8) |
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| 88 | gsinv(ind) = 0.d |
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| 89 | gcosv(ind) = 1.d |
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| 90 | ; |
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| 91 | return |
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| 92 | END |
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