!********************************************************************** ! Copyright 1998,1999,2000,2001,2002,2005,2007,2008,2009,2010 * ! Andreas Stohl, Petra Seibert, A. Frank, Gerhard Wotawa, * ! Caroline Forster, Sabine Eckhardt, John Burkhart, Harald Sodemann * ! * ! This file is part of FLEXPART. * ! * ! FLEXPART is free software: you can redistribute it and/or modify * ! it under the terms of the GNU General Public License as published by* ! the Free Software Foundation, either version 3 of the License, or * ! (at your option) any later version. * ! * ! FLEXPART is distributed in the hope that it will be useful, * ! but WITHOUT ANY WARRANTY; without even the implied warranty of * ! MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * ! GNU General Public License for more details. * ! * ! You should have received a copy of the GNU General Public License * ! along with FLEXPART. If not, see . * !********************************************************************** subroutine interpol_rain(yy1,yy2,yy3,nxmax,nymax,nzmax,nx, & ny,memind,xt,yt,level,itime1,itime2,itime,yint1,yint2,yint3) ! i i i i i i i !i i i i i i i i o o o !**************************************************************************** ! * ! Interpolation of meteorological fields on 2-d model layers. * ! In horizontal direction bilinear interpolation interpolation is used. * ! Temporally a linear interpolation is used. * ! Three fields are interpolated at the same time. * ! * ! This is a special version of levlininterpol to save CPU time. * ! * ! 1 first time * ! 2 second time * ! * ! * ! Author: A. Stohl * ! * ! 30 August 1996 * ! * !**************************************************************************** ! * ! Variables: * ! * ! dt1,dt2 time differences between fields and current position * ! dz1,dz2 z distance between levels and current position * ! height(nzmax) heights of the model levels * ! indexh help variable * ! indz the level closest to the current trajectory position * ! indzh help variable * ! itime current time * ! itime1 time of the first wind field * ! itime2 time of the second wind field * ! ix,jy x,y coordinates of lower left subgrid point * ! level level at which interpolation shall be done * ! memind(3) points to the places of the wind fields * ! nx,ny actual field dimensions in x,y and z direction * ! nxmax,nymax,nzmax maximum field dimensions in x,y and z direction * ! xt current x coordinate * ! yint the final interpolated value * ! yt current y coordinate * ! yy(0:nxmax,0:nymax,nzmax,3) meteorological field used for interpolation * ! zt current z coordinate * ! * !**************************************************************************** implicit none integer :: nx,ny,nxmax,nymax,nzmax,memind(2),m,ix,jy,ixp,jyp integer :: itime,itime1,itime2,level,indexh real :: yy1(0:nxmax-1,0:nymax-1,nzmax,2) real :: yy2(0:nxmax-1,0:nymax-1,nzmax,2) real :: yy3(0:nxmax-1,0:nymax-1,nzmax,2) real :: ddx,ddy,rddx,rddy,dt1,dt2,dt,y1(2),y2(2),y3(2) real :: xt,yt,yint1,yint2,yint3,p1,p2,p3,p4 ! If point at border of grid -> small displacement into grid !*********************************************************** if (xt.ge.real(nx-1)) xt=real(nx-1)-0.00001 if (yt.ge.real(ny-1)) yt=real(ny-1)-0.00001 !********************************************************************** ! 1.) Bilinear horizontal interpolation ! This has to be done separately for 2 fields (Temporal) !******************************************************* ! Determine the lower left corner and its distance to the current position !************************************************************************* ix=int(xt) jy=int(yt) ixp=ix+1 jyp=jy+1 ddx=xt-real(ix) ddy=yt-real(jy) rddx=1.-ddx rddy=1.-ddy p1=rddx*rddy p2=ddx*rddy p3=rddx*ddy p4=ddx*ddy ! Loop over 2 time steps !*********************** do m=1,2 indexh=memind(m) y1(m)=p1*yy1(ix ,jy ,level,indexh) & + p2*yy1(ixp,jy ,level,indexh) & + p3*yy1(ix ,jyp,level,indexh) & + p4*yy1(ixp,jyp,level,indexh) y2(m)=p1*yy2(ix ,jy ,level,indexh) & + p2*yy2(ixp,jy ,level,indexh) & + p3*yy2(ix ,jyp,level,indexh) & + p4*yy2(ixp,jyp,level,indexh) y3(m)=p1*yy3(ix ,jy ,level,indexh) & + p2*yy3(ixp,jy ,level,indexh) & + p3*yy3(ix ,jyp,level,indexh) & + p4*yy3(ixp,jyp,level,indexh) end do !************************************ ! 2.) Temporal interpolation (linear) !************************************ dt1=real(itime-itime1) dt2=real(itime2-itime) dt=dt1+dt2 yint1=(y1(1)*dt2+y1(2)*dt1)/dt yint2=(y2(1)*dt2+y2(2)*dt1)/dt yint3=(y3(1)*dt2+y3(2)*dt1)/dt end subroutine interpol_rain