diff --git a/mediator/fd_nems.yaml b/mediator/fd_nems.yaml
index 75db4177d..314a3ab01 100644
--- a/mediator/fd_nems.yaml
+++ b/mediator/fd_nems.yaml
@@ -188,6 +188,11 @@
        canonical_units: W m-2
        description: atmosphere import - merged ocn/ice flux
      #
+     - standard_name: Sa_ofrac
+       alias: openwater_frac_in_atm
+       canonical_units: 1
+       description: atm export to mediator - open water ocean fraction (varies with time)
+     #
      - standard_name: Sa_u10m
        alias: inst_zonal_wind_height10m
        canonical_units: m s-1