Allow reading from files with multiple time steps

Inst_eddies/input_ssh.f90

@@ -61,6 +61,13 @@ contains
     integer unit
     integer ncid, dimid, varid
 
+    integer:: nc_time = 1
+    ! Index, 1-based, in the NetCDF time coordinate, if any, of the
+    ! time slice to read. If there is no time coordinate, then leave
+    ! nc_time to its default 1 value. If there is a time coordinate
+    ! then we assume that the dimensions of the ssh, u and v NetCDF
+    ! variables are longitude, latitude and time, in Fortran order.
+
     real:: corner_deg(2) = huge(0.)
     ! longitude and latitude of the corner of the whole grid, in degrees
 
@@ -69,7 +76,7 @@ contains
     integer copy
     namelist /grid_nml/ corner_deg, step_deg, nlon, nlat, periodic, &
          uniform_lon_lat
-    namelist /input_ssh_nml/ periodic, uniform_lon_lat
+    namelist /input_ssh_nml/ periodic, uniform_lon_lat, nc_time
 
     !----------------------------------------------------------------------
 
@@ -121,7 +128,7 @@ contains
 
     ! Read ssh, u and v:
 
-    call get_var(periodic, ssh, ncid, name = "adt", &
+    call get_var(periodic, ssh, ncid, nc_time, name = "adt", &
          new_fill_value = huge(0.))
     ! (We cannot keep the original fill value because Contour_531
     ! works with an upper limit for valid values.)
@@ -131,7 +138,7 @@ contains
        call nf95_open(u_fname, nf95_nowrite, ncid)
     end if
 
-    call get_var(periodic, u, ncid, name = "ugos", &
+    call get_var(periodic, u, ncid, nc_time, name = "ugos", &
          new_fill_value = ieee_value(0., IEEE_QUIET_NAN))
 
     if (v_fname /= u_fname) then
@@ -139,7 +146,7 @@ contains
        call nf95_open(v_fname, nf95_nowrite, ncid)
     end if
 
-    call get_var(periodic, v, ncid, name = "vgos", &
+    call get_var(periodic, v, ncid, nc_time, name = "vgos", &
          new_fill_value = ieee_value(0., IEEE_QUIET_NAN))
     ! (We will need quiet NaNs rather the original fill values for u and
     ! v when we compute the max-speed contours and when we search the
@@ -150,7 +157,7 @@ contains
 
   !*********************************************************************
 
-  subroutine get_var(periodic, values, ncid, name, new_fill_value)
+  subroutine get_var(periodic, values, ncid, nc_time, name, new_fill_value)
 
     ! Read a NetCDF variable, change the missing value and extend it
     ! in longitude if periodic.
@@ -169,6 +176,14 @@ contains
     ! declaration references periodic.
 
     integer, intent(in):: ncid
+
+    integer, intent(in):: nc_time
+    ! Index, 1-based, in the NetCDF time coordinate, if any, of the
+    ! time slice to read. If there is no time coordinate, then nc_time
+    ! should be equal to 1. If there is a time coordinate then we
+    ! assume that the dimension of the NetCDF variable to read are
+    ! longitude, latitude and time, in Fortran order.
+
     character(len = *), intent(in):: name ! of NetCDF variable
     real, intent(in):: new_fill_value
 
@@ -179,7 +194,14 @@ contains
     !-------------------------------------------------------------------------
 
     call nf95_inq_varid(ncid, name, varid)
-    call nf95_get_var(ncid, varid, values(1:nlon, :))
+
+    if (nc_time == 1) then
+       call nf95_get_var(ncid, varid, values(1:nlon, :))
+    else
+       call nf95_get_var(ncid, varid, values(1:nlon, :), &
+            start = [1, 1, nc_time])
+    end if
+
     call nf95_get_missing(ncid, varid, Fill_Value)
 
     ! Change the missing value: