[6] | 1 | !********************************************************************** |
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| 2 | ! Copyright 1998,1999,2000,2001,2002,2005,2007,2008,2009,2010 * |
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| 3 | ! Andreas Stohl, Petra Seibert, A. Frank, Gerhard Wotawa, * |
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| 4 | ! Caroline Forster, Sabine Eckhardt, John Burkhart, Harald Sodemann * |
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| 5 | ! * |
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| 6 | ! This file is part of FLEXPART. * |
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| 7 | ! * |
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| 8 | ! FLEXPART is free software: you can redistribute it and/or modify * |
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| 9 | ! it under the terms of the GNU General Public License as published by* |
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| 10 | ! the Free Software Foundation, either version 3 of the License, or * |
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| 11 | ! (at your option) any later version. * |
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| 12 | ! * |
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| 13 | ! FLEXPART is distributed in the hope that it will be useful, * |
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| 14 | ! but WITHOUT ANY WARRANTY; without even the implied warranty of * |
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| 15 | ! MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * |
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| 16 | ! GNU General Public License for more details. * |
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| 17 | ! * |
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| 18 | ! You should have received a copy of the GNU General Public License * |
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| 19 | ! along with FLEXPART. If not, see <http://www.gnu.org/licenses/>. * |
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| 20 | !********************************************************************** |
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| 21 | |
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| 22 | subroutine interpol_wind_short_nests(itime,xt,yt,zt) |
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| 23 | ! i i i i |
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| 24 | !***************************************************************************** |
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| 25 | ! * |
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| 26 | ! This subroutine interpolates the wind data to current trajectory position.* |
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| 27 | ! * |
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| 28 | ! Author: A. Stohl * |
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| 29 | ! * |
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| 30 | ! 16 December 1997 * |
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| 31 | ! * |
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| 32 | ! Revision March 2005 by AST : all output variables in common block * |
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| 33 | ! * |
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| 34 | !***************************************************************************** |
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| 35 | ! * |
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| 36 | ! Variables: * |
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| 37 | ! u,v,w wind components * |
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| 38 | ! itime [s] current temporal position * |
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| 39 | ! memtime(3) [s] times of the wind fields in memory * |
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| 40 | ! xt,yt,zt coordinates position for which wind data shall be * |
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| 41 | ! calculated * |
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| 42 | ! * |
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| 43 | ! Constants: * |
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| 44 | ! * |
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| 45 | !***************************************************************************** |
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| 46 | |
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| 47 | use par_mod |
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| 48 | use com_mod |
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| 49 | use interpol_mod |
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| 50 | |
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| 51 | implicit none |
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| 52 | |
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| 53 | integer :: itime |
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| 54 | real :: xt,yt,zt |
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| 55 | |
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| 56 | ! Auxiliary variables needed for interpolation |
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| 57 | real :: dz1,dz2,dz |
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| 58 | real :: u1(2),v1(2),w1(2),uh(2),vh(2),wh(2) |
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| 59 | integer :: i,m,n,indexh,indzh |
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| 60 | |
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| 61 | |
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| 62 | !******************************************** |
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| 63 | ! Multilinear interpolation in time and space |
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| 64 | !******************************************** |
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| 65 | |
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| 66 | ddx=xt-real(ix) |
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| 67 | ddy=yt-real(jy) |
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| 68 | rddx=1.-ddx |
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| 69 | rddy=1.-ddy |
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| 70 | p1=rddx*rddy |
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| 71 | p2=ddx*rddy |
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| 72 | p3=rddx*ddy |
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| 73 | p4=ddx*ddy |
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| 74 | |
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| 75 | ! Calculate variables for time interpolation |
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| 76 | !******************************************* |
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| 77 | |
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| 78 | dt1=real(itime-memtime(1)) |
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| 79 | dt2=real(memtime(2)-itime) |
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| 80 | dtt=1./(dt1+dt2) |
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| 81 | |
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| 82 | ! Determine the level below the current position for u,v |
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| 83 | !******************************************************* |
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| 84 | |
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| 85 | do i=2,nz |
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| 86 | if (height(i).gt.zt) then |
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| 87 | indz=i-1 |
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| 88 | goto 6 |
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| 89 | endif |
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| 90 | end do |
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| 91 | 6 continue |
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| 92 | |
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| 93 | |
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| 94 | ! Vertical distance to the level below and above current position |
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| 95 | !**************************************************************** |
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| 96 | |
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| 97 | dz=1./(height(indz+1)-height(indz)) |
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| 98 | dz1=(zt-height(indz))*dz |
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| 99 | dz2=(height(indz+1)-zt)*dz |
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| 100 | |
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| 101 | |
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| 102 | !********************************************************************** |
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| 103 | ! 1.) Bilinear horizontal interpolation |
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| 104 | ! This has to be done separately for 6 fields (Temporal(2)*Vertical(3)) |
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| 105 | !********************************************************************** |
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| 106 | |
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| 107 | ! Loop over 2 time steps and 2 levels |
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| 108 | !************************************ |
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| 109 | |
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| 110 | do m=1,2 |
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| 111 | indexh=memind(m) |
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| 112 | do n=1,2 |
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| 113 | indzh=indz+n-1 |
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| 114 | |
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| 115 | u1(n)=p1*uun(ix ,jy ,indzh,indexh,ngrid) & |
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| 116 | +p2*uun(ixp,jy ,indzh,indexh,ngrid) & |
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| 117 | +p3*uun(ix ,jyp,indzh,indexh,ngrid) & |
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| 118 | +p4*uun(ixp,jyp,indzh,indexh,ngrid) |
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| 119 | v1(n)=p1*vvn(ix ,jy ,indzh,indexh,ngrid) & |
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| 120 | +p2*vvn(ixp,jy ,indzh,indexh,ngrid) & |
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| 121 | +p3*vvn(ix ,jyp,indzh,indexh,ngrid) & |
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| 122 | +p4*vvn(ixp,jyp,indzh,indexh,ngrid) |
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| 123 | w1(n)=p1*wwn(ix ,jy ,indzh,indexh,ngrid) & |
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| 124 | +p2*wwn(ixp,jy ,indzh,indexh,ngrid) & |
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| 125 | +p3*wwn(ix ,jyp,indzh,indexh,ngrid) & |
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| 126 | +p4*wwn(ixp,jyp,indzh,indexh,ngrid) |
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| 127 | |
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| 128 | end do |
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| 129 | |
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| 130 | |
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| 131 | !********************************** |
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| 132 | ! 2.) Linear vertical interpolation |
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| 133 | !********************************** |
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| 134 | |
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| 135 | uh(m)=dz2*u1(1)+dz1*u1(2) |
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| 136 | vh(m)=dz2*v1(1)+dz1*v1(2) |
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| 137 | wh(m)=dz2*w1(1)+dz1*w1(2) |
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| 138 | end do |
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| 139 | |
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| 140 | |
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| 141 | !************************************ |
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| 142 | ! 3.) Temporal interpolation (linear) |
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| 143 | !************************************ |
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| 144 | |
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| 145 | u=(uh(1)*dt2+uh(2)*dt1)*dtt |
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| 146 | v=(vh(1)*dt2+vh(2)*dt1)*dtt |
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| 147 | w=(wh(1)*dt2+wh(2)*dt1)*dtt |
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| 148 | |
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| 149 | end subroutine interpol_wind_short_nests |
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