[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 | function psih (z,l) |
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| 23 | |
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| 24 | !***************************************************************************** |
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| 25 | ! * |
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| 26 | ! Calculation of the stability correction term * |
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| 27 | ! * |
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| 28 | ! AUTHOR: Matthias Langer, adapted by Andreas Stohl (6 August 1993) * |
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| 29 | ! Update: G. Wotawa, 11 October 1994 * |
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| 30 | ! * |
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| 31 | ! Literature: * |
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| 32 | ! [1] C.A.Paulson (1970), A Mathematical Representation of Wind Speed * |
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| 33 | ! and Temperature Profiles in the Unstable Atmospheric Surface * |
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| 34 | ! Layer. J.Appl.Met.,Vol.9.(1970), pp.857-861. * |
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| 35 | ! * |
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| 36 | ! [2] A.C.M. Beljaars, A.A.M. Holtslag (1991), Flux Parameterization over* |
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| 37 | ! Land Surfaces for Atmospheric Models. J.Appl.Met. Vol. 30,pp 327-* |
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| 38 | ! 341 * |
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| 39 | ! * |
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| 40 | ! Variables: * |
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| 41 | ! L = Monin-Obukhov-length [m] * |
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| 42 | ! z = height [m] * |
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| 43 | ! zeta = auxiliary variable * |
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| 44 | ! * |
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| 45 | ! Constants: * |
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| 46 | ! eps = 1.2E-38, SUN-underflow: to avoid division by zero errors * |
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| 47 | ! * |
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| 48 | !***************************************************************************** |
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| 49 | |
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| 50 | use par_mod |
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| 51 | |
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| 52 | implicit none |
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| 53 | |
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| 54 | real :: psih,x,z,zeta,l |
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| 55 | real,parameter :: a=1.,b=0.667,c=5.,d=0.35,eps=1.e-20 |
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| 56 | |
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| 57 | if ((l.ge.0).and.(l.lt.eps)) then |
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| 58 | l=eps |
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| 59 | else if ((l.lt.0).and.(l.gt.(-1.*eps))) then |
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| 60 | l=-1.*eps |
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| 61 | endif |
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| 62 | |
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| 63 | if ((log10(z)-log10(abs(l))).lt.log10(eps)) then |
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| 64 | psih=0. |
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| 65 | else |
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| 66 | zeta=z/l |
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| 67 | if (zeta.gt.0.) then |
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| 68 | psih = - (1.+0.667*a*zeta)**(1.5) - b*(zeta-c/d)*exp(-d*zeta) & |
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| 69 | - b*c/d + 1. |
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| 70 | else |
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| 71 | x=(1.-16.*zeta)**(.25) |
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| 72 | psih=2.*log((1.+x*x)/2.) |
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| 73 | end if |
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| 74 | end if |
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| 75 | |
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| 76 | end function psih |
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