[e200b7a] | 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 hanna_short(z) |
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| 23 | ! i |
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| 24 | !***************************************************************************** |
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| 25 | ! * |
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| 26 | ! Computation of \sigma_i and \tau_L based on the scheme of Hanna (1982) * |
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| 27 | ! * |
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| 28 | ! Author: A. Stohl * |
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| 29 | ! * |
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| 30 | ! 4 December 1997 * |
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| 31 | ! * |
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| 32 | !***************************************************************************** |
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| 33 | ! * |
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| 34 | ! Variables: * |
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| 35 | ! dsigwdz [1/s] vertical gradient of sigw * |
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| 36 | ! ol [m] Obukhov length * |
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| 37 | ! sigu, sigv, sigw standard deviations of turbulent velocity fluctuations * |
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| 38 | ! tlu [s] Lagrangian time scale for the along wind component. * |
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| 39 | ! tlv [s] Lagrangian time scale for the cross wind component. * |
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| 40 | ! tlw [s] Lagrangian time scale for the vertical wind component. * |
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| 41 | ! ust, ustar [m/s] friction velocity * |
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| 42 | ! wst, wstar [m/s] convective velocity scale * |
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| 43 | ! * |
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| 44 | !***************************************************************************** |
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| 45 | |
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| 46 | use par_mod |
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| 47 | use com_mod |
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| 48 | use hanna_mod |
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| 49 | |
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| 50 | implicit none |
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| 51 | |
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| 52 | real :: z |
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| 53 | |
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| 54 | |
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| 55 | |
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| 56 | !********************** |
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| 57 | ! 1. Neutral conditions |
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| 58 | !********************** |
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| 59 | |
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| 60 | if (h/abs(ol).lt.1.) then |
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| 61 | ust=max(1.e-4,ust) |
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| 62 | sigw=1.3*exp(-2.e-4*z/ust) |
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| 63 | dsigwdz=-2.e-4*sigw |
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| 64 | sigw=sigw*ust+1.e-2 |
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| 65 | tlw=0.5*z/sigw/(1.+1.5e-3*z/ust) |
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| 66 | |
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| 67 | |
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| 68 | !*********************** |
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| 69 | ! 2. Unstable conditions |
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| 70 | !*********************** |
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| 71 | |
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| 72 | else if (ol.lt.0.) then |
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| 73 | |
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| 74 | |
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| 75 | ! Determine sigmas |
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| 76 | !***************** |
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| 77 | |
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| 78 | sigw=sqrt(1.2*wst**2*(1.-.9*zeta)*zeta**0.66666+ & |
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| 79 | (1.8-1.4*zeta)*ust**2)+1.e-2 |
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| 80 | dsigwdz=0.5/sigw/h*(-1.4*ust**2+wst**2* & |
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| 81 | (0.8*max(zeta,1.e-3)**(-.33333)-1.8*zeta**0.66666)) |
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| 82 | |
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| 83 | |
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| 84 | ! Determine average Lagrangian time scale |
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| 85 | !**************************************** |
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| 86 | |
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| 87 | if (z.lt.abs(ol)) then |
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| 88 | tlw=0.1*z/(sigw*(0.55-0.38*abs(z/ol))) |
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| 89 | else if (zeta.lt.0.1) then |
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| 90 | tlw=0.59*z/sigw |
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| 91 | else |
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| 92 | tlw=0.15*h/sigw*(1.-exp(-5*zeta)) |
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| 93 | endif |
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| 94 | |
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| 95 | |
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| 96 | !********************* |
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| 97 | ! 3. Stable conditions |
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| 98 | !********************* |
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| 99 | |
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| 100 | else |
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| 101 | sigw=1.e-2+1.3*ust*(1.-zeta) |
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| 102 | dsigwdz=-1.3*ust/h |
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| 103 | tlw=0.1*h/sigw*zeta**0.8 |
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| 104 | endif |
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| 105 | |
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| 106 | |
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| 107 | tlu=max(10.,tlu) |
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| 108 | tlv=max(10.,tlv) |
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| 109 | tlw=max(30.,tlw) |
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| 110 | if (dsigwdz.eq.0.) dsigwdz=1.e-10 |
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| 111 | |
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| 112 | end subroutine hanna_short |
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