1 | ! SPDX-FileCopyrightText: FLEXPART 1998-2019, see flexpart_license.txt |
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2 | ! SPDX-License-Identifier: GPL-3.0-or-later |
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3 | |
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4 | subroutine re_initialize_particle(zp,ust,wst,h,sigmaw,wp,nrand,ol) |
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5 | ! i i i i i io io i |
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6 | !=============== CBL skewed vertical profiles and formulation of LHH 1996 with profile of w3 from lHB 2000 ====== |
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7 | !=============== LHH formulation has been modified to account for variable density profiles and backward in time or forward in time simulations ====== |
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8 | !=============== this routine re-initiaalize particle velocity if a numerical instability in the cbl scheme generated a NaN value ====== |
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9 | !=============== the particle velocity is extracted from the updraft and downdraft distribution as required ====== |
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10 | !=============== the re-initialization si not perfect see e.g. Cassiani et al(2015) BLM ====== |
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11 | !====================================================================================================================================================== |
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12 | !====================================================================================================================================================== |
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13 | use par_mod, only:pi |
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14 | use com_mod, only:ldirect,rannumb |
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15 | |
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16 | implicit none |
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17 | |
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18 | |
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19 | real :: usurad2,usurad2p,C0,costluar4,eps |
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20 | parameter (usurad2=0.7071067812,usurad2p=0.3989422804,C0=2,costluar4=0.66667,eps=0.000001) |
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21 | |
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22 | integer idum,nrand |
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23 | real :: wp,zp,ust,wst,h,dens,ddens,sigmaw,dsigmawdz,tlw,dcas,dcas1 !,ran3,gasdev |
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24 | real :: w3,w2 |
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25 | real :: z, & |
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26 | skew, & |
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27 | skew2, & |
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28 | radw2, & |
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29 | fluarw,fluarw2, & |
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30 | rluarw, & |
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31 | xluarw, & |
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32 | aluarw, & |
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33 | bluarw, & |
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34 | sigmawa, & |
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35 | sigmawb, & |
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36 | ath, & |
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37 | bth, & |
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38 | wb,wa |
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39 | real timedir |
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40 | real ol,transition |
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41 | |
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42 | !--------------------------------------------------------------------------- |
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43 | !timedir direction of time forward (1) or backward(-1) |
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44 | nrand=nrand+1 |
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45 | dcas1=rannumb(nrand) |
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46 | timedir=ldirect |
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47 | z=zp/h |
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48 | transition=1. |
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49 | |
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50 | if (-h/ol.lt.15) transition=((sin((((-h/ol)+10.)/10.)*pi)))/2.+0.5 |
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51 | |
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52 | w2=sigmaw*sigmaw |
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53 | w3=(((1.2*z*((1.-z)**(3./2.)))+eps)*wst**3)*transition |
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54 | skew=w3/(w2**1.5) |
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55 | skew2=skew*skew |
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56 | radw2=sqrt(w2) !sigmaw |
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57 | |
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58 | fluarw=costluar4*skew**0.333333333333333 |
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59 | fluarw2=fluarw*fluarw |
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60 | rluarw=(1.+fluarw2)**3.*skew2/((3.+fluarw2)**2.*fluarw2) !-> r |
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61 | xluarw=rluarw**0.5 !(1.+fluarw2)**1.5*skew/((3.+fluarw2)*fluarw) !----> r^1/2 |
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62 | |
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63 | aluarw=0.5*(1.-xluarw/(4.+rluarw)**0.5) |
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64 | bluarw=1.-aluarw |
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65 | |
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66 | sigmawa=radw2*(bluarw/(aluarw*(1.+fluarw2)))**0.5 |
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67 | sigmawb=radw2*(aluarw/(bluarw*(1.+fluarw2)))**0.5 |
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68 | |
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69 | wa=(fluarw*sigmawa) |
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70 | wb=(fluarw*sigmawb) |
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71 | |
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72 | |
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73 | |
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74 | if ((sign(1.,wp)*timedir).gt.0) then !updraft |
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75 | 100 wp=(dcas1*sigmawa+wa) |
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76 | if (wp.lt.0) then |
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77 | nrand=nrand+1 |
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78 | dcas1=rannumb(nrand) |
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79 | goto 100 |
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80 | end if |
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81 | wp=wp*timedir |
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82 | else if ((sign(1.,wp)*timedir).lt.0) then !downdraft |
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83 | 101 wp=(dcas1*sigmawb-wb) |
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84 | if (wp.gt.0) then |
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85 | nrand=nrand+1 |
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86 | dcas1=rannumb(nrand) |
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87 | goto 101 |
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88 | end if |
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89 | wp=wp*timedir |
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90 | end if |
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91 | |
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92 | return |
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93 | end subroutine re_initialize_particle |
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