calcpv_nests.f90 8.57 KB
Newer Older
Matthias Langer's avatar
 
Matthias Langer committed
1
subroutine calcpv_nests(l,n,uuhn,vvhn,pvhn)
2
  !                     i i  i    i    o
Matthias Langer's avatar
 
Matthias Langer committed
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
  !*****************************************************************************
  !                                                                            *
  !  Calculation of potential vorticity on 3-d nested grid                     *
  !                                                                            *
  !     Author: P. James                                                       *
  !     22 February 2000                                                       *
  !                                                                            *
  !*****************************************************************************
  !                                                                            *
  ! Variables:                                                                 *
  ! n                  temporal index for meteorological fields (1 to 2)       *
  ! l                  index of current nest                                   *
  !                                                                            *
  ! Constants:                                                                 *
  !                                                                            *
  !*****************************************************************************

  use par_mod
  use com_mod

  implicit none

  integer :: n,ix,jy,i,j,k,kl,ii,jj,klvrp,klvrm,klpt,kup,kdn,kch
  integer :: jyvp,jyvm,ixvp,ixvm,jumpx,jumpy,jux,juy,ivrm,ivrp,ivr
  integer :: nlck,l
  real :: vx(2),uy(2),phi,tanphi,cosphi,dvdx,dudy,f
29
30
  real :: theta,thetap,thetam,dthetadp,dt1,dt2,dt
  real :: ppml(0:nxmaxn-1,0:nymaxn-1,nuvzmax),ppmk(0:nxmaxn-1,0:nymaxn-1,nuvzmax)
Matthias Langer's avatar
 
Matthias Langer committed
31
32
33
34
35
36
37
38
39
40
41
  real :: thup,thdn
  real,parameter :: eps=1.e-5,p0=101325
  real :: uuhn(0:nxmaxn-1,0:nymaxn-1,nuvzmax,maxnests)
  real :: vvhn(0:nxmaxn-1,0:nymaxn-1,nuvzmax,maxnests)
  real :: pvhn(0:nxmaxn-1,0:nymaxn-1,nuvzmax,maxnests)

  ! Set number of levels to check for adjacent theta
  nlck=nuvz/3
  !
  ! Loop over entire grid
  !**********************
42
43
44
45
46
47
48
  do kl=1,nuvz
    do jy=0,nyn(l)-1
      do ix=0,nxn(l)-1
         ppml(ix,jy,kl)=akz(kl)+bkz(kl)*psn(ix,jy,1,n,l)
      enddo
    enddo
  enddo
49
50
!  ppmk=(100000./ppml)**kappa
  ppmk(0:nxn(l)-1,0:nyn(l)-1,1:nuvz)=(100000./ppml(0:nxn(l)-1,0:nyn(l)-1,1:nuvz))**kappa
51

Matthias Langer's avatar
 
Matthias Langer committed
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
  do jy=0,nyn(l)-1
    phi = (ylat0n(l) + jy * dyn(l)) * pi / 180.
    f = 0.00014585 * sin(phi)
    tanphi = tan(phi)
    cosphi = cos(phi)
  ! Provide a virtual jy+1 and jy-1 in case we are on domain edge (Lat)
      jyvp=jy+1
      jyvm=jy-1
      if (jy.eq.0) jyvm=0
      if (jy.eq.nyn(l)-1) jyvp=nyn(l)-1
  ! Define absolute gap length
      jumpy=2
      if (jy.eq.0.or.jy.eq.nyn(l)-1) jumpy=1
      juy=jumpy
  !
    do ix=0,nxn(l)-1
  ! Provide a virtual ix+1 and ix-1 in case we are on domain edge (Long)
      ixvp=ix+1
      ixvm=ix-1
      jumpx=2
      if (ix.eq.0) ixvm=0
      if (ix.eq.nxn(l)-1) ixvp=nxn(l)-1
      ivrp=ixvp
      ivrm=ixvm
  ! Define absolute gap length
      if (ix.eq.0.or.ix.eq.nxn(l)-1) jumpx=1
      jux=jumpx
  !
  ! Loop over the vertical
  !***********************

      do kl=1,nuvz
84
        theta=tthn(ix,jy,kl,n,l)*ppmk(ix,jy,kl)
Matthias Langer's avatar
 
Matthias Langer committed
85
86
87
88
89
90
91
92
        klvrp=kl+1
        klvrm=kl-1
        klpt=kl
  ! If top or bottom level, dthetadp is evaluated between the current
  ! level and the level inside, otherwise between level+1 and level-1
  !
        if (klvrp.gt.nuvz) klvrp=nuvz
        if (klvrm.lt.1) klvrm=1
93
94
95
        thetap=tthn(ix,jy,klvrp,n,l)*ppmk(ix,jy,klvrp)
        thetam=tthn(ix,jy,klvrm,n,l)*ppmk(ix,jy,klvrm)
        dthetadp=(thetap-thetam)/(ppml(ix,jy,klvrp)-ppml(ix,jy,klvrm))
Matthias Langer's avatar
 
Matthias Langer committed
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117

  ! Compute vertical position at pot. temperature surface on subgrid
  ! and the wind at that position
  !*****************************************************************
  ! a) in x direction
        ii=0
        do i=ixvm,ixvp,jumpx
          ivr=i
          ii=ii+1
  ! Search adjacent levels for current theta value
  ! Spiral out from current level for efficiency
          kup=klpt-1
          kdn=klpt
          kch=0
40        continue
  ! Upward branch
          kup=kup+1
          if (kch.ge.nlck) goto 21     ! No more levels to check,
  !                                       ! and no values found
          if (kup.ge.nuvz) goto 41
          kch=kch+1
          k=kup
118
119
          thdn=tthn(ivr,jy,k,n,l)*ppmk(ivr,jy,k)
          thup=tthn(ivr,jy,k+1,n,l)*ppmk(ivr,jy,k+1)
Matthias Langer's avatar
 
Matthias Langer committed
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139

      if (((thdn.ge.theta).and.(thup.le.theta)).or. &
           ((thdn.le.theta).and.(thup.ge.theta))) then
              dt1=abs(theta-thdn)
              dt2=abs(theta-thup)
              dt=dt1+dt2
              if (dt.lt.eps) then   ! Avoid division by zero error
                dt1=0.5             ! G.W., 10.4.1996
                dt2=0.5
                dt=1.0
              endif
    vx(ii)=(vvhn(ivr,jy,k,l)*dt2+vvhn(ivr,jy,k+1,l)*dt1)/dt
              goto 20
            endif
41        continue
  ! Downward branch
          kdn=kdn-1
          if (kdn.lt.1) goto 40
          kch=kch+1
          k=kdn
140
141
          thdn=tthn(ivr,jy,k,n,l)*ppmk(ivr,jy,k)
          thup=tthn(ivr,jy,k+1,n,l)*ppmk(ivr,jy,k+1)
Matthias Langer's avatar
 
Matthias Langer committed
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
      if (((thdn.ge.theta).and.(thup.le.theta)).or. &
           ((thdn.le.theta).and.(thup.ge.theta))) then
              dt1=abs(theta-thdn)
              dt2=abs(theta-thup)
              dt=dt1+dt2
              if (dt.lt.eps) then   ! Avoid division by zero error
                dt1=0.5             ! G.W., 10.4.1996
                dt2=0.5
                dt=1.0
              endif
    vx(ii)=(vvhn(ivr,jy,k,l)*dt2+vvhn(ivr,jy,k+1,l)*dt1)/dt
              goto 20
            endif
            goto 40
  ! This section used when no values were found
21      continue
  ! Must use vv at current level and long. jux becomes smaller by 1
        vx(ii)=vvhn(ix,jy,kl,l)
        jux=jux-1
  ! Otherwise OK
20        continue
        end do
      if (jux.gt.0) then
      dvdx=(vx(2)-vx(1))/real(jux)/(dxn(l)*pi/180.)
      else
      dvdx=vvhn(ivrp,jy,kl,l)-vvhn(ivrm,jy,kl,l)
      dvdx=dvdx/real(jumpx)/(dxn(l)*pi/180.)
  ! Only happens if no equivalent theta value
  ! can be found on either side, hence must use values
  ! from either side, same pressure level.
      end if

  ! b) in y direction

        jj=0
        do j=jyvm,jyvp,jumpy
          jj=jj+1
  ! Search adjacent levels for current theta value
  ! Spiral out from current level for efficiency
          kup=klpt-1
          kdn=klpt
          kch=0
70        continue
  ! Upward branch
          kup=kup+1
          if (kch.ge.nlck) goto 51     ! No more levels to check,
  !                                     ! and no values found
          if (kup.ge.nuvz) goto 71
          kch=kch+1
          k=kup
192
193
          thdn=tthn(ix,j,k,n,l)*ppmk(ix,j,k)
          thup=tthn(ix,j,k+1,n,l)*ppmk(ix,j,k+1)
Matthias Langer's avatar
 
Matthias Langer committed
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
      if (((thdn.ge.theta).and.(thup.le.theta)).or. &
           ((thdn.le.theta).and.(thup.ge.theta))) then
              dt1=abs(theta-thdn)
              dt2=abs(theta-thup)
              dt=dt1+dt2
              if (dt.lt.eps) then   ! Avoid division by zero error
                dt1=0.5             ! G.W., 10.4.1996
                dt2=0.5
                dt=1.0
              endif
        uy(jj)=(uuhn(ix,j,k,l)*dt2+uuhn(ix,j,k+1,l)*dt1)/dt
              goto 50
            endif
71        continue
  ! Downward branch
          kdn=kdn-1
          if (kdn.lt.1) goto 70
          kch=kch+1
          k=kdn
213
214
          thdn=tthn(ix,j,k,n,l)*ppmk(ix,j,k)
          thup=tthn(ix,j,k+1,n,l)*ppmk(ix,j,k+1)
Matthias Langer's avatar
 
Matthias Langer committed
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
      if (((thdn.ge.theta).and.(thup.le.theta)).or. &
           ((thdn.le.theta).and.(thup.ge.theta))) then
              dt1=abs(theta-thdn)
              dt2=abs(theta-thup)
              dt=dt1+dt2
              if (dt.lt.eps) then   ! Avoid division by zero error
                dt1=0.5             ! G.W., 10.4.1996
                dt2=0.5
                dt=1.0
              endif
        uy(jj)=(uuhn(ix,j,k,l)*dt2+uuhn(ix,j,k+1,l)*dt1)/dt
              goto 50
            endif
            goto 70
  ! This section used when no values were found
51      continue
  ! Must use uu at current level and lat. juy becomes smaller by 1
        uy(jj)=uuhn(ix,jy,kl,l)
        juy=juy-1
  ! Otherwise OK
50        continue
        end do
      if (juy.gt.0) then
      dudy=(uy(2)-uy(1))/real(juy)/(dyn(l)*pi/180.)
      else
      dudy=uuhn(ix,jyvp,kl,l)-uuhn(ix,jyvm,kl,l)
      dudy=dudy/real(jumpy)/(dyn(l)*pi/180.)
      end if
  !
      pvhn(ix,jy,kl,l)=dthetadp*(f+(dvdx/cosphi-dudy &
           +uuhn(ix,jy,kl,l)*tanphi)/r_earth)*(-1.e6)*9.81

  !
  ! Resest jux and juy
      jux=jumpx
      juy=jumpy
      end do
    end do
  end do
  !
end subroutine calcpv_nests