Read `input_ssh_nml` before

Read `input_ssh_nml` before reading the NetCDF files. Preparing to
read from the namelist whether the grid is uniform.

Inst_eddies/input_ssh.f90

@@ -57,6 +57,9 @@ contains
 
     !----------------------------------------------------------------------
 
+    periodic = .false. ! default value
+    print *, "input_ssh: Enter input_ssh_nml:"
+    read(unit = *, nml = input_ssh_nml)
     call nf95_open(ssh_fname, nf95_nowrite, ncid)
     call nf95_find_coord(ncid, dimid = dimid, varid = varid, &
          std_name = "longitude")
@@ -77,9 +80,6 @@ contains
     write(unit, nml = grid_nml)
     close(unit)
     step = step_deg * deg_to_rad
-    periodic = .false. ! default value
-    print *, "input_ssh: Enter input_ssh_nml:"
-    read(unit = *, nml = input_ssh_nml)
     if (periodic) call assert(4 * max_radius(1) < nlon, "input_ssh: max_radius")
     copy = merge(max_radius(1), 0, periodic)
     allocate(ssh(1 - copy:nlon + copy, nlat), u(1 - copy:nlon + copy, nlat), &