[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 | real function zenithangle(ylat,xlon,jul) |
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| 23 | |
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| 24 | !********************************************************************* |
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| 25 | ! * |
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| 26 | ! Author: G. WOTAWA * |
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| 27 | ! Date: 1993-11-17 * |
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| 28 | ! Project: POP-M * |
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| 29 | ! Last update: * |
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| 30 | ! * |
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| 31 | !********************************************************************* |
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| 32 | ! * |
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| 33 | ! DESCRIPTION: This function returns the sinus of solar * |
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| 34 | ! elevation as a function of geographic longitude, * |
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| 35 | ! latitude and GMT-Time. * |
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| 36 | ! * |
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| 37 | !********************************************************************* |
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| 38 | ! * |
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| 39 | ! INPUT: * |
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| 40 | ! * |
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| 41 | ! ylat geographical latitude [DEG] * |
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| 42 | ! xlon geographical longitude [DEG] * |
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| 43 | ! jjjj Year * |
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| 44 | ! mm Month * |
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| 45 | ! dd Day * |
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| 46 | ! hh Hour * |
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| 47 | ! minute Minute * |
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| 48 | ! * |
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| 49 | !********************************************************************* |
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| 50 | |
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| 51 | use par_mod, only: dp |
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| 52 | |
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| 53 | implicit none |
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| 54 | |
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| 55 | integer :: jjjj,mm,id,iu,minute,yyyymmdd,hhmmss |
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| 56 | integer :: ndaynum |
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| 57 | real :: sinsol,solelev,ylat,xlon |
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| 58 | real :: rnum,rylat,ttime,dekl,rdekl,eq |
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| 59 | real,parameter :: pi=3.1415927 |
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| 60 | real(kind=dp) :: jul |
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| 61 | |
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| 62 | call caldate(jul,yyyymmdd,hhmmss) |
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| 63 | jjjj=yyyymmdd/10000 |
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| 64 | mm=yyyymmdd/100-jjjj*100 |
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| 65 | id=yyyymmdd-jjjj*10000-mm*100 |
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| 66 | iu=hhmmss/10000 |
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| 67 | minute=hhmmss/100-100*iu |
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| 68 | |
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| 69 | ndaynum=31*(mm-1)+id |
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| 70 | if(mm.gt.2) ndaynum=ndaynum-int(0.4*mm+2.3) |
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| 71 | if((mm.gt.2).and.(jjjj/4*4.eq.jjjj)) ndaynum=ndaynum+1 |
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| 72 | |
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| 73 | rnum=2.*pi*ndaynum/365. |
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| 74 | rylat=pi*ylat/180. |
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| 75 | ttime=real(iu)+real(minute)/60. |
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| 76 | |
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| 77 | dekl=0.396+3.631*sin(rnum)+0.038*sin(2.*rnum)+0.077*sin(3.*rnum)- & |
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| 78 | 22.97*cos(rnum)-0.389*cos(2.*rnum)-0.158*cos(3.*rnum) |
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| 79 | rdekl=pi*dekl/180. |
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| 80 | |
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| 81 | eq=(0.003-7.343*sin(rnum)-9.47*sin(2.*rnum)- & |
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| 82 | 0.329*sin(3.*rnum)-0.196*sin(4.*rnum)+ & |
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| 83 | 0.552*cos(rnum)-3.020*cos(2.*rnum)- & |
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| 84 | 0.076*cos(3.*rnum)-0.125*cos(4.*rnum))/60. |
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| 85 | |
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| 86 | sinsol=sin(rylat)*sin(rdekl)+cos(rylat)*cos(rdekl)* & |
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| 87 | cos((ttime-12.+xlon/15.+eq)*pi/12.) |
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| 88 | ! Calculate the maximum solar elevation on that day |
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| 89 | !sinsol=sin(rylat)*sin(rdekl)+cos(rylat)*cos(rdekl)* |
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| 90 | ! & cos((eq)*pi/12.) |
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| 91 | solelev=asin(sinsol)*180./pi |
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| 92 | zenithangle=90.-solelev |
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| 93 | |
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| 94 | return |
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| 95 | end function zenithangle |
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