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obsinter_z1d.h90 in branches/UKMO/dev_r5518_obs_oper_update/NEMOGCM/NEMO/OPA_SRC/OBS – NEMO

source: branches/UKMO/dev_r5518_obs_oper_update/NEMOGCM/NEMO/OPA_SRC/OBS/obsinter_z1d.h90 @ 7960

Last change on this file since 7960 was 7960, checked in by jwhile, 8 years ago

Updated namelist_ref and 2nd attemp at updating SVN keywords

File size: 7.4 KB
Line 
1   !!----------------------------------------------------------------------
2   !! NEMO/OPA 3.3 , NEMO Consortium (2010)
3   !! $Id$
4   !! Software governed by the CeCILL licence (NEMOGCM/NEMO_CeCILL.txt)
5   !!----------------------------------------------------------------------
6
7   SUBROUTINE obs_int_z1d( kpk, kkco, k1dint, kdep, &
8      &                    pobsdep, pobsk, pobs2k,  &
9      &                    pobs, pdep, pobsmask )
10      !!---------------------------------------------------------------------
11      !!
12      !!                   ***  ROUTINE obs_int_z1d ***
13      !!
14      !! ** Purpose : Vertical interpolation to the observation point.
15      !! 
16      !! ** Method  : If k1dint = 0 then use linear interpolation.
17      !!              If k1dint = 1 then use cubic spline interpolation.
18      !!
19      !! ** Action  :
20      !!
21      !! References :
22      !!
23      !! History
24      !!      ! 97-11 (A. Weaver, S. Ricci, N. Daget)
25      !!      ! 06-03 (G. Smith) Conversion to F90 for use with NEMOVAR
26      !!      ! 06-10 (A. Weaver) Cleanup
27      !!      ! 07-01 (K. Mogensen) Use profile rather than single level
28      !!---------------------------------------------------------------------
29
30      !! * Arguments
31      INTEGER, INTENT(IN) :: kpk        ! Number of vertical levels
32      INTEGER, INTENT(IN) :: k1dint     ! 0 = linear; 1 = cubic spline interpolation
33      INTEGER, INTENT(IN) :: kdep       ! Number of levels in profile
34      INTEGER, INTENT(IN), DIMENSION(kdep) :: &
35         & kkco                 ! Array indicies for interpolation
36      REAL(KIND=wp), INTENT(IN), DIMENSION(kdep) :: &
37         & pobsdep              ! Depth of the observation
38      REAL(KIND=wp), INTENT(IN), DIMENSION(kpk) :: &
39         & pobsk,  &            ! Model profile at a given (lon,lat)
40         & pobs2k, &            ! 2nd derivative of the interpolating function
41         & pdep,   &            ! Model depth array
42         & pobsmask             ! Vertical mask
43      REAL(KIND=wp), INTENT(OUT), DIMENSION(kdep) :: &
44         & pobs                 ! Model equivalent at observation point
45 
46      !! * Local declarations
47      REAL(KIND=wp) :: z1dm       ! Distance above and below obs to model grid points
48      REAL(KIND=wp) :: z1dp         
49      REAL(KIND=wp) :: zsum       ! Dummy variables for computation
50      REAL(KIND=wp) :: zsum2
51      INTEGER :: jdep             ! Observation depths loop variable
52   
53      !------------------------------------------------------------------------
54      ! Loop over all observation depths
55      !------------------------------------------------------------------------
56
57      DO jdep = 1, kdep
58
59         !---------------------------------------------------------------------
60         ! Initialization
61         !---------------------------------------------------------------------
62         z1dm = ( pdep(kkco(jdep)) - pobsdep(jdep)      )
63         z1dp = ( pobsdep(jdep)    - pdep(kkco(jdep)-1) )
64         IF ( pobsmask(kkco(jdep)) == 0.0_wp ) z1dp = 0.0_wp
65
66         zsum = z1dm + z1dp
67         
68         IF ( k1dint == 0 ) THEN
69
70            !-----------------------------------------------------------------
71            !  Linear interpolation
72            !-----------------------------------------------------------------
73            pobs(jdep) = (   z1dm * pobsk(kkco(jdep)-1) &
74               &           + z1dp * pobsk(kkco(jdep)  ) ) / zsum
75
76         ELSEIF ( k1dint == 1 ) THEN
77
78            !-----------------------------------------------------------------
79            ! Cubic spline interpolation
80            !-----------------------------------------------------------------
81            zsum2 = zsum * zsum
82            pobs(jdep)  = (  z1dm                             * pobsk (kkco(jdep)-1) &
83               &           + z1dp                             * pobsk (kkco(jdep)  ) &
84               &           + ( z1dm * ( z1dm * z1dm - zsum2 ) * pobs2k(kkco(jdep)-1) &
85               &           +   z1dp * ( z1dp * z1dp - zsum2 ) * pobs2k(kkco(jdep)  ) &
86               &             ) / 6.0_wp                                              &
87               &          ) / zsum
88
89         ENDIF
90      END DO
91
92   END SUBROUTINE obs_int_z1d
93
94   SUBROUTINE obs_int_z1d_spl( kpk, pobsk, pobs2k, &
95      &                        pdep, pobsmask )
96      !!--------------------------------------------------------------------
97      !!
98      !!                  *** ROUTINE obs_int_z1d_spl ***
99      !!
100      !! ** Purpose : Compute the local vector of vertical second-derivatives
101      !!              of the interpolating function used with a cubic spline.
102      !! 
103      !! ** Method  :
104      !!
105      !!    Top and bottom boundary conditions on the 2nd derivative are
106      !!    set to zero.
107      !!
108      !! ** Action  :
109      !!
110      !! References :
111      !!
112      !! History
113      !!      ! 01-11 (A. Weaver, S. Ricci, N. Daget)
114      !!      ! 06-03 (G. Smith) Conversion to F90 for use with NEMOVAR
115      !!      ! 06-10 (A. Weaver) Cleanup
116      !!----------------------------------------------------------------------
117     
118      !! * Arguments
119      INTEGER, INTENT(IN) :: kpk               ! Number of vertical levels
120      REAL(KIND=wp), INTENT(IN), DIMENSION(kpk) :: &
121         & pobsk, &          ! Model profile at a given (lon,lat)
122         & pdep,  &          ! Model depth array
123         & pobsmask          ! Vertical mask
124      REAL(KIND=wp), INTENT(OUT), DIMENSION(kpk) :: &
125         & pobs2k            ! 2nd derivative of the interpolating function
126 
127      !! * Local declarations
128      INTEGER :: jk
129      REAL(KIND=wp) :: za
130      REAL(KIND=wp) :: zb
131      REAL(KIND=wp) :: zc
132      REAL(KIND=wp) :: zpa
133      REAL(KIND=wp) :: zkm
134      REAL(KIND=wp) :: zkp
135      REAL(KIND=wp) :: zk
136      REAL(KIND=wp), DIMENSION(kpk-1) :: &
137         & zs, &
138         & zp, &
139         & zu, &
140         & zv
141
142      !-----------------------------------------------------------------------
143      ! Matrix initialisation
144      !-----------------------------------------------------------------------
145      zs(1) =  0.0_wp
146      zp(1) =  0.0_wp
147      zv(1) = -0.5_wp
148      DO jk = 2, kpk-1
149         zs(jk) =  ( pdep(jk  ) - pdep(jk-1) ) &
150            &    / ( pdep(jk+1) - pdep(jk-1) )
151         zp(jk) = zs(jk) * zv(jk-1) + 2.0_wp
152         zv(jk) = ( zs(jk) - 1.0_wp ) / zp(jk)
153      END DO
154 
155      !-----------------------------------------------------------------------
156      ! Solution of the tridiagonal system
157      !-----------------------------------------------------------------------
158 
159      ! Top boundary condition
160      zu(1) = 0.0_wp
161 
162      DO jk = 2, kpk-1
163         za = pdep(jk+1) - pdep(jk-1)
164         zb = pdep(jk+1) - pdep(jk  )
165         zc = pdep(jk  ) - pdep(jk-1)
166 
167         zpa = 6.0_wp / ( zp(jk) * za )
168         zkm = zpa / zc
169         zkp = zpa / zb
170         zk  = - ( zkm + zkp )
171 
172         zu(jk) =  pobsk(jk+1) * zkp  &
173            &    + pobsk(jk  ) * zk   &
174            &    + pobsk(jk-1) * zkm  &
175            &    + zu(jk-1) * ( -zs(jk) / zp(jk) )
176      END DO
177 
178      !-----------------------------------------------------------------------
179      ! Second derivative
180      !-----------------------------------------------------------------------
181      pobs2k(kpk) = 0.0_wp
182 
183      ! Bottom boundary condition
184      DO jk = kpk-1, 1, -1
185         pobs2k(jk) = zv(jk) * pobs2k(jk+1) + zu(jk)
186         IF ( pobsmask(jk+1) == 0.0_wp ) pobs2k(jk) = 0.0_wp
187      END DO
188 
189  END SUBROUTINE obs_int_z1d_spl
190
191
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