[6328] | 1 | SUBROUTINE gradient_conserv(NX1, NY1, src_array, sou_mask, & |
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| 2 | src_latitudes, src_longitudes, & |
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| 3 | id_per, cd_per, & |
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| 4 | grad_lat, grad_lon) |
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| 5 | |
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| 6 | !**** |
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| 7 | ! ***************************** |
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| 8 | ! * OASIS ROUTINE - LEVEL ? * |
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| 9 | ! * ------------- ------- * |
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| 10 | ! ***************************** |
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| 11 | ! |
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| 12 | !**** *gradient_conserv* - calculate gradients for conservative remapping |
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| 13 | ! |
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| 14 | ! Purpose: |
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| 15 | ! ------- |
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| 16 | ! Calculation of gradients in latitudinal and longitudinal direction. |
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| 17 | ! In a first step the gradients in direction of source-grid rows |
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| 18 | ! and lines are calculated. Then they are rotated to longitudinal |
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| 19 | ! and latitudinal direction, using the scalar product. |
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| 20 | ! This routine works for logically rectangular grids, only. |
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| 21 | ! |
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| 22 | !** Interface: |
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| 23 | ! --------- |
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| 24 | ! *CALL* *gradient_conserv*(NX1, NY1, src_array, sou_mask, src_latitudes, & |
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| 25 | ! src_longitudes, grad_lat, grad_lon) |
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| 26 | ! |
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| 27 | ! Input: |
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| 28 | ! ----- |
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| 29 | ! NX1 : grid dimension in x-direction (integer) |
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| 30 | ! NY1 : grid dimension in y-direction (integer) |
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| 31 | ! src_array : array on source grid (real 2D) |
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| 32 | ! sou_mask : source grid mask (integer 2D) |
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| 33 | ! src_latitudes : latitudes on source grid (real 2D) |
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| 34 | ! src_longitudes : longitudes on source grid (real 2D) |
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| 35 | ! id_per : number of overlapping points for source grid |
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| 36 | ! cd_per : grip periodicity type |
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| 37 | ! |
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| 38 | ! Output: |
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| 39 | ! ------ |
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| 40 | ! grad_lat : gradient in latitudinal direction (real 2D) |
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| 41 | ! grad_lon : gradient in longitudinal direction (real 2D) |
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| 42 | ! |
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| 43 | ! History: |
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| 44 | ! ------- |
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| 45 | ! Version Programmer Date Description |
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| 46 | ! ------- ---------- ---- ----------- |
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| 47 | ! 2.5 V. Gayler 2001/09/20 created |
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| 48 | ! |
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| 49 | ! %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
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| 50 | |
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| 51 | IMPLICIT NONE |
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| 52 | |
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| 53 | INTEGER, PARAMETER :: wp = SELECTED_REAL_KIND(12,307) ! double |
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| 54 | !----------------------------------------------------------------------- |
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| 55 | ! INTENT(IN) |
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| 56 | !----------------------------------------------------------------------- |
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| 57 | INTEGER, INTENT(IN) :: & |
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| 58 | NX1, NY1, & ! source grid dimensions |
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| 59 | id_per ! nbr of overlapping grid points |
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| 60 | |
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| 61 | CHARACTER*8, INTENT(IN) :: & |
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| 62 | cd_per ! grip periodicity type |
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| 63 | |
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| 64 | REAL (kind=wp), DIMENSION(NX1,NY1), INTENT(IN) :: & |
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| 65 | src_array ! array on source grid |
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| 66 | |
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| 67 | INTEGER, DIMENSION(NX1,NY1), INTENT(IN) :: & |
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| 68 | sou_mask ! source grid mask |
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| 69 | |
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| 70 | REAL (kind=wp), DIMENSION(NX1,NY1), INTENT(IN) :: & |
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| 71 | src_latitudes, & ! source grid latitudes |
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| 72 | src_longitudes ! source grid longitudes |
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| 73 | |
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| 74 | !----------------------------------------------------------------------- |
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| 75 | ! INTENT(OUT) |
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| 76 | !----------------------------------------------------------------------- |
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| 77 | REAL (kind=wp), DIMENSION(NX1,NY1), INTENT(OUT) :: & |
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| 78 | grad_lat, & ! gradient in latitudinal direction |
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| 79 | grad_lon ! gradient in longitudinal direction |
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| 80 | |
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| 81 | !----------------------------------------------------------------------- |
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| 82 | ! LOCAL VARIABLES |
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| 83 | !----------------------------------------------------------------------- |
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| 84 | INTEGER :: & |
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| 85 | i, j, & ! looping indicees |
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| 86 | ip1, jp1, im1, jm1 |
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| 87 | |
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| 88 | REAL (kind=wp) :: & |
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| 89 | distance_rad ! distance in rad |
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| 90 | |
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| 91 | REAL (kind=wp) :: & |
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| 92 | dVar_i, dVar_j, & ! difference of Var in i / j direction |
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| 93 | dlat_i, dlat_j, & ! difference in lat in i / j direction |
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| 94 | dlon_i, dlon_j, & ! difference in lon in i / j direction |
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| 95 | dist_i, dist_j, & ! distance in i / j direction |
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| 96 | grad_i, grad_j, & ! gradient in i / j direction |
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| 97 | ABSold, ABSnew, lat_factor |
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| 98 | |
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| 99 | REAL (kind=wp), DIMENSION(NX1,NY1) :: & |
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| 100 | src_lon, & ! source grid longitudes [radiants] |
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| 101 | src_lat, & ! source grid latitudes [radiants] |
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| 102 | pi180 ! conversion factor: deg -> rad |
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| 103 | REAL (kind=wp), PARAMETER :: & |
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| 104 | pi = 3.14159265358979323846, & ! PI |
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| 105 | pi2 = 2.0d0*pi ! 2PI |
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| 106 | |
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| 107 | INTEGER, PARAMETER :: il_maskval= 1 ! in our grids sea_value = 0 and land_value = 1 |
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| 108 | |
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| 109 | !----------------------------------------------------------------------- |
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| 110 | ! |
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| 111 | !! IF (nlogprt .GE. 2) THEN |
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| 112 | !! WRITE (UNIT = nulou,FMT = *)' ' |
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| 113 | !! WRITE (UNIT = nulou,FMT = *)' Entering routine gradient_conserv ' |
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| 114 | !! WRITE (UNIT = nulou,FMT = *)' ' |
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| 115 | !! CALL FLUSH(nulou) |
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| 116 | !! ENDIF |
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| 117 | ! |
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| 118 | ! Transformation from degree to radiant |
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| 119 | ! ------------------------------------- |
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| 120 | pi180 = 1.74532925199432957692e-2 ! =PI/180 |
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| 121 | |
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| 122 | src_lon = src_longitudes * pi180 |
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| 123 | src_lat = src_latitudes * pi180 |
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| 124 | |
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| 125 | !----------------------------------------------------------------------- |
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| 126 | |
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| 127 | DO i = 1, NX1 |
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| 128 | |
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| 129 | DO j = 1, NY1 |
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| 130 | |
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| 131 | IF (sou_mask(i,j) /= il_maskval) THEN |
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| 132 | |
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| 133 | ip1 = i + 1 |
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| 134 | im1 = i - 1 |
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| 135 | IF (i == NX1) THEN |
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| 136 | IF (cd_per == 'P') ip1 = 1 + id_per ! the 0-meridian |
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| 137 | IF (cd_per == 'R') ip1 = NX1 |
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| 138 | ENDIF |
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| 139 | IF (i == 1 ) THEN |
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| 140 | IF (cd_per == 'P') im1 = NX1 - id_per |
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| 141 | IF (cd_per == 'R') im1 = 1 |
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| 142 | ENDIF |
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| 143 | jp1 = j + 1 |
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| 144 | jm1 = j - 1 |
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| 145 | IF (j == NY1) jp1 = NY1 ! treatment of the last.. |
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| 146 | IF (j == 1 ) jm1 = 1 ! .. and the first grid-row |
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| 147 | |
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| 148 | IF (sou_mask(ip1,j) == il_maskval) ip1 = i |
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| 149 | IF (sou_mask(im1,j) == il_maskval) im1 = i |
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| 150 | IF (sou_mask(i,jp1) == il_maskval) jp1 = j |
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| 151 | IF (sou_mask(i,jm1) == il_maskval) jm1 = j |
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| 152 | |
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| 153 | ! difference between neighbouring datapoints |
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| 154 | dVar_i = src_array(ip1,j) - src_array(im1,j) |
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| 155 | dVar_j = src_array(i,jp1) - src_array(i,jm1) |
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| 156 | |
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| 157 | ! difference in latitudes |
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| 158 | dlat_i = src_lat(ip1,j) - src_lat(im1,j) |
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| 159 | dlat_j = src_lat(i,jp1) - src_lat(i,jm1) |
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| 160 | |
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| 161 | ! difference in longitudes |
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| 162 | dlon_i = src_lon(ip1,j) - src_lon(im1,j) |
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| 163 | IF (dlon_i > pi) dlon_i = dlon_i - pi2 |
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| 164 | IF (dlon_i < (-pi)) dlon_i = dlon_i + pi2 |
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| 165 | dlon_j = src_lon(i,jp1) - src_lon(i,jm1) |
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| 166 | IF (dlon_j > pi) dlon_j = dlon_j - pi2 |
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| 167 | IF (dlon_j < (-pi)) dlon_j = dlon_j + pi2 |
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| 168 | lat_factor = COS(src_lat(i,j)) |
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| 169 | dlon_i = dlon_i * lat_factor |
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| 170 | dlon_j = dlon_j * lat_factor |
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| 171 | |
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| 172 | ! distance |
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| 173 | dist_i = distance_rad(src_lon(ip1,j), src_lat(ip1,j), & |
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| 174 | src_lon(im1,j), src_lat(im1,j)) |
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| 175 | dist_j = distance_rad(src_lon(i,jp1), src_lat(i,jp1), & |
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| 176 | src_lon(i,jm1), src_lat(i,jm1)) |
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| 177 | |
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| 178 | ! gradients: dVar / distance (= vector lenght) |
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| 179 | IF (dist_i /= 0.) THEN |
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| 180 | grad_i = dVar_i / dist_i |
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| 181 | ELSE |
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| 182 | grad_i = 0 |
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| 183 | ENDIF |
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| 184 | IF (dist_j /= 0.) THEN |
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| 185 | grad_j = dVar_j / dist_j |
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| 186 | ELSE |
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| 187 | grad_j = 0 |
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| 188 | ENDIF |
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| 189 | |
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| 190 | ! projection by scalar product |
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| 191 | ! ---------------------------- |
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| 192 | grad_lon(i,j) = grad_i * dlon_i + grad_j * dlat_i |
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| 193 | grad_lat(i,j) = grad_i * dlon_j + grad_j * dlat_j |
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| 194 | |
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| 195 | IF (dist_i /= 0) then |
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| 196 | grad_lon(i,j) = grad_lon(i,j) / dist_i |
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| 197 | ELSE |
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| 198 | grad_lon(i,j) = 0 |
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| 199 | ENDIF |
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| 200 | IF (dist_j /= 0) then |
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| 201 | grad_lat(i,j) = grad_lat(i,j) / dist_j |
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| 202 | ELSE |
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| 203 | grad_lat(i,j) = 0. |
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| 204 | ENDIF |
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| 205 | |
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| 206 | ! correct skale |
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| 207 | ! ------------- |
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| 208 | ABSold = SQRT(grad_i**2 + grad_j**2) |
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| 209 | ABSnew = SQRT(grad_lon(i,j)**2 + grad_lat(i,j)**2) |
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| 210 | IF (ABSnew > 1.E-10) THEN |
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| 211 | ! grad_lon(i,j) = grad_lon(i,j)*ABSold/ABSnew |
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| 212 | grad_lon(i,j) = grad_lon(i,j) |
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| 213 | ELSE |
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| 214 | grad_lon(i,j) = 0.0 |
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| 215 | ENDIF |
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| 216 | |
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| 217 | ! test orthogonality |
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| 218 | ! ------------------ |
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| 219 | IF ((dlon_i*dlon_j+dlat_j*dlat_i) > 0.1) THEN |
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| 220 | print*, 'ORTHOGONAL? ', i, j, (dlon_i*dlon_j+dlat_j*dlat_i) |
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| 221 | ENDIF |
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| 222 | |
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| 223 | ELSE |
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| 224 | |
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| 225 | grad_lat(i,j) = 0. |
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| 226 | grad_lon(i,j) = 0. |
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| 227 | |
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| 228 | ENDIF |
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| 229 | |
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| 230 | ENDDO |
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| 231 | ENDDO |
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| 232 | !! IF (nlogprt .GE. 2) THEN |
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| 233 | !! WRITE (UNIT = nulou,FMT = *)' ' |
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| 234 | !! WRITE (UNIT = nulou,FMT = *)' Leaving routine gradient ' |
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| 235 | !! WRITE (UNIT = nulou,FMT = *)' ' |
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| 236 | !! CALL FLUSH(nulou) |
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| 237 | !! ENDIF |
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| 238 | |
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| 239 | END SUBROUTINE gradient_conserv |
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