diff --git a/bld/build-namelist b/bld/build-namelist
index 8413f96f57..e88ca9ecc4 100755
--- a/bld/build-namelist
+++ b/bld/build-namelist
@@ -3848,9 +3848,9 @@ foreach my $name (@nl_groups) { $nl_group{$name} = ''; }
 # nature of ozone data passed to surface models -- only if cmeps (nuopc) coupling is used
 if ($opts{'cmeps'}) {
   if ($rad_prog_ozone) {
-    add_default($nl, 'atm_ozone_frequency', 'val'=>'instantaneous');
+    add_default($nl, 'atm_ozone_frequency', 'val'=>'subdaily');
   } else {
-    add_default($nl, 'atm_ozone_frequency', 'val'=>'monthly_interpolated');
+    add_default($nl, 'atm_ozone_frequency', 'val'=>'multiday_average');
   }
 }
 $outfile = "$opts{'dir'}/drv_flds_in";
diff --git a/bld/namelist_files/namelist_definition.xml b/bld/namelist_files/namelist_definition.xml
index 7a3da3c322..f592fd1f71 100644
--- a/bld/namelist_files/namelist_definition.xml
+++ b/bld/namelist_files/namelist_definition.xml
@@ -6808,7 +6808,7 @@ Default: set by build-namelist.
 <!-- 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">
+       group="ozone_coupling_nl" valid_values="subdaily,multiday_average">
 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