Add atm_ozone_frequency drv_flds_in namelist variable

The logic for how this is set still needs to be fixed

bld/build-namelist

@@ -3841,8 +3841,10 @@ my $outfile;
 my %nl_group = ();
 foreach my $name (@nl_groups) { $nl_group{$name} = ''; }
 
-# Dry deposition and MEGAN VOC emis namelists
-@comp_groups = qw(drydep_inparm megan_emis_nl fire_emis_nl carma_inparm ndep_inparm);
+# Dry deposition, MEGAN VOC emis and ozone namelists
+@comp_groups = qw(drydep_inparm megan_emis_nl fire_emis_nl carma_inparm ndep_inparm ozone_coupling_nl);
+# FIXME The following add_default call needs to be moved and the right logic needs to be put in place
+add_default($nl, 'atm_ozone_frequency', 'val'=>'monthly_interpolated');
 $outfile = "$opts{'dir'}/drv_flds_in";
 $nl->write($outfile, 'groups'=>\@comp_groups);
 if ($print>=1) {

bld/namelist_files/namelist_definition.xml

@@ -6805,6 +6805,17 @@ List of fluxes needed by the CARMA model, from CLM to CAM.
 Default: set by build-namelist.
 </entry>
 
+<!-- Ozone namelist variables shared between CAM and driver -->
+
+<entry id="atm_ozone_frequency" type="char*64" category="ozone_coupling"
+       group="ozone_coupling_nl" valid_values="instantaneous,monthly_interpolated">
+Frequency of surface ozone field passed from CAM to surface components.
+Surface ozone is passed every coupling interval, but this namelist flag
+indicates whether the timestep-level values are interpolated from a
+coarser temporal resolution.
+Default: set by build-namelist.
+</entry>
+
 <!-- WACCM_GHG Chemistry -->
 
 <entry id="waccm_forcing_file" type="char*256" input_pathname="rel:waccm_forcing_datapath" category="waccm_sc"