1 | ! |
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2 | ! $Id: top_bound.f90 5312 2024-11-01 12:22:08Z jyg $ |
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3 | ! |
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4 | SUBROUTINE top_bound(vcov,ucov,teta,masse,dt) |
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5 | |
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6 | USE iniprint_mod_h |
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7 | USE comgeom2_mod_h |
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8 | USE comdissipn_mod_h |
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9 | USE comconst_mod, ONLY: iflag_top_bound, mode_top_bound, & |
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10 | tau_top_bound |
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11 | USE comvert_mod, ONLY: presnivs, preff, scaleheight |
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12 | |
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13 | USE dimensions_mod, ONLY: iim, jjm, llm, ndm |
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14 | USE paramet_mod_h |
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15 | IMPLICIT NONE |
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16 | ! |
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17 | |
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18 | |
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19 | |
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20 | |
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21 | ! .. DISSIPATION LINEAIRE A HAUT NIVEAU, RUN MESO, |
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22 | ! F. LOTT DEC. 2006 |
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23 | ! ( 10/12/06 ) |
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24 | |
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25 | !======================================================================= |
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26 | ! |
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27 | ! Auteur: F. LOTT |
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28 | ! ------- |
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29 | ! |
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30 | ! Objet: |
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31 | ! ------ |
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32 | ! |
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33 | ! Dissipation lin�aire (ex top_bound de la physique) |
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34 | ! |
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35 | !======================================================================= |
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36 | |
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37 | ! top_bound sponge layer model: |
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38 | ! Quenching is modeled as: A(t)=Am+A0*exp(-lambda*t) |
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39 | ! where Am is the zonal average of the field (or zero), and lambda the inverse |
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40 | ! of the characteristic quenching/relaxation time scale |
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41 | ! Thus, assuming Am to be time-independent, field at time t+dt is given by: |
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42 | ! A(t+dt)=A(t)-(A(t)-Am)*(1-exp(-lambda*t)) |
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43 | ! Moreover lambda can be a function of model level (see below), and relaxation |
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44 | ! can be toward the average zonal field or just zero (see below). |
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45 | |
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46 | ! NB: top_bound sponge is only called from leapfrog if ok_strato=.true. |
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47 | |
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48 | ! sponge parameters: (loaded/set in conf_gcm.F ; stored in comconst_mod) |
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49 | ! iflag_top_bound=0 for no sponge |
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50 | ! iflag_top_bound=1 for sponge over 4 topmost layers |
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51 | ! iflag_top_bound=2 for sponge from top to ~1% of top layer pressure |
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52 | ! mode_top_bound=0: no relaxation |
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53 | ! mode_top_bound=1: u and v relax towards 0 |
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54 | ! mode_top_bound=2: u and v relax towards their zonal mean |
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55 | ! mode_top_bound=3: u,v and pot. temp. relax towards their zonal mean |
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56 | ! tau_top_bound : inverse of charactericstic relaxation time scale at |
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57 | ! the topmost layer (Hz) |
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58 | |
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59 | |
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60 | |
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61 | ! Arguments: |
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62 | ! ---------- |
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63 | |
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64 | real,intent(inout) :: ucov(iip1,jjp1,llm) ! covariant zonal wind |
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65 | real,intent(inout) :: vcov(iip1,jjm,llm) ! covariant meridional wind |
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66 | real,intent(inout) :: teta(iip1,jjp1,llm) ! potential temperature |
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67 | real,intent(in) :: masse(iip1,jjp1,llm) ! mass of atmosphere |
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68 | real,intent(in) :: dt ! time step (s) of sponge model |
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69 | |
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70 | ! Local: |
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71 | ! ------ |
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72 | |
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73 | REAL :: massebx(iip1,jjp1,llm),masseby(iip1,jjm,llm),zm |
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74 | REAL :: uzon(jjp1,llm),vzon(jjm,llm),tzon(jjp1,llm) |
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75 | |
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76 | integer :: i |
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77 | REAL,SAVE :: rdamp(llm) ! quenching coefficient |
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78 | real,save :: lambda(llm) ! inverse or quenching time scale (Hz) |
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79 | |
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80 | LOGICAL,SAVE :: first=.true. |
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81 | |
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82 | INTEGER :: j,l |
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83 | |
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84 | if (iflag_top_bound.eq.0) return |
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85 | |
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86 | if (first) then |
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87 | if (iflag_top_bound.eq.1) then |
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88 | ! sponge quenching over the topmost 4 atmospheric layers |
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89 | lambda(:)=0. |
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90 | lambda(llm)=tau_top_bound |
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91 | lambda(llm-1)=tau_top_bound/2. |
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92 | lambda(llm-2)=tau_top_bound/4. |
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93 | lambda(llm-3)=tau_top_bound/8. |
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94 | else if (iflag_top_bound.eq.2) then |
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95 | ! sponge quenching over topmost layers down to pressures which are |
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96 | ! higher than 100 times the topmost layer pressure |
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97 | lambda(:)=tau_top_bound & |
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98 | *max(presnivs(llm)/presnivs(:)-0.01,0.) |
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99 | endif |
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100 | |
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101 | ! quenching coefficient rdamp(:) |
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102 | ! rdamp(:)=dt*lambda(:) ! Explicit Euler approx. |
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103 | rdamp(:)=1.-exp(-lambda(:)*dt) |
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104 | |
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105 | write(lunout,*)'TOP_BOUND mode',mode_top_bound |
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106 | write(lunout,*)'Sponge layer coefficients' |
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107 | write(lunout,*)'p (Pa) z(km) tau(s) 1./tau (Hz)' |
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108 | do l=1,llm |
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109 | if (rdamp(l).ne.0.) then |
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110 | write(lunout,'(6(1pe12.4,1x))') & |
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111 | presnivs(l),log(preff/presnivs(l))*scaleheight, & |
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112 | 1./lambda(l),lambda(l) |
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113 | endif |
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114 | enddo |
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115 | first=.false. |
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116 | endif ! of if (first) |
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117 | |
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118 | CALL massbar(masse,massebx,masseby) |
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119 | |
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120 | ! ! compute zonal average of vcov and u |
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121 | if (mode_top_bound.ge.2) then |
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122 | do l=1,llm |
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123 | do j=1,jjm |
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124 | vzon(j,l)=0. |
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125 | zm=0. |
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126 | do i=1,iim |
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127 | ! NB: we can work using vcov zonal mean rather than v since the |
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128 | ! cv coefficient (which relates the two) only varies with latitudes |
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129 | vzon(j,l)=vzon(j,l)+vcov(i,j,l)*masseby(i,j,l) |
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130 | zm=zm+masseby(i,j,l) |
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131 | enddo |
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132 | vzon(j,l)=vzon(j,l)/zm |
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133 | enddo |
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134 | enddo |
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135 | |
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136 | do l=1,llm |
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137 | do j=2,jjm ! excluding poles |
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138 | uzon(j,l)=0. |
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139 | zm=0. |
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140 | do i=1,iim |
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141 | uzon(j,l)=uzon(j,l)+massebx(i,j,l)*ucov(i,j,l)/cu(i,j) |
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142 | zm=zm+massebx(i,j,l) |
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143 | enddo |
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144 | uzon(j,l)=uzon(j,l)/zm |
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145 | enddo |
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146 | enddo |
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147 | else ! ucov and vcov will relax towards 0 |
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148 | vzon(:,:)=0. |
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149 | uzon(:,:)=0. |
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150 | endif ! of if (mode_top_bound.ge.2) |
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151 | |
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152 | ! ! compute zonal average of potential temperature, if necessary |
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153 | if (mode_top_bound.ge.3) then |
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154 | do l=1,llm |
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155 | do j=2,jjm ! excluding poles |
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156 | zm=0. |
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157 | tzon(j,l)=0. |
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158 | do i=1,iim |
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159 | tzon(j,l)=tzon(j,l)+teta(i,j,l)*masse(i,j,l) |
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160 | zm=zm+masse(i,j,l) |
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161 | enddo |
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162 | tzon(j,l)=tzon(j,l)/zm |
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163 | enddo |
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164 | enddo |
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165 | endif ! of if (mode_top_bound.ge.3) |
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166 | |
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167 | if (mode_top_bound.ge.1) then |
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168 | ! ! Apply sponge quenching on vcov: |
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169 | do l=1,llm |
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170 | do i=1,iip1 |
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171 | do j=1,jjm |
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172 | vcov(i,j,l)=vcov(i,j,l) & |
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173 | -rdamp(l)*(vcov(i,j,l)-vzon(j,l)) |
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174 | enddo |
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175 | enddo |
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176 | enddo |
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177 | |
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178 | ! ! Apply sponge quenching on ucov: |
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179 | do l=1,llm |
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180 | do i=1,iip1 |
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181 | do j=2,jjm ! excluding poles |
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182 | ucov(i,j,l)=ucov(i,j,l) & |
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183 | -rdamp(l)*(ucov(i,j,l)-cu(i,j)*uzon(j,l)) |
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184 | enddo |
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185 | enddo |
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186 | enddo |
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187 | endif ! of if (mode_top_bound.ge.1) |
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188 | |
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189 | if (mode_top_bound.ge.3) then |
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190 | ! ! Apply sponge quenching on teta: |
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191 | do l=1,llm |
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192 | do i=1,iip1 |
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193 | do j=2,jjm ! excluding poles |
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194 | teta(i,j,l)=teta(i,j,l) & |
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195 | -rdamp(l)*(teta(i,j,l)-tzon(j,l)) |
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196 | enddo |
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197 | enddo |
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198 | enddo |
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199 | endif ! of if (mode_top_bound.ge.3) |
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200 | |
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201 | END SUBROUTINE top_bound |
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