diff --git a/tests/default_vars.sh b/tests/default_vars.sh
index 4c1c259488..e3f3088195 100644
--- a/tests/default_vars.sh
+++ b/tests/default_vars.sh
@@ -624,6 +624,8 @@ export DO_UGWP_V1_W_GSLDRAG=.false.
 export DO_UGWP_V0_OROG_ONLY=.false.
 export DO_GSL_DRAG_LS_BL=.false.
 export DO_GSL_DRAG_SS=.true.
+export DO_GWD_OPT_PSL=.true.
+export PSL_GWD_DX_FACTOR=6.0
 export DO_GSL_DRAG_TOFD=.false.
 export DO_UGWP_V1=.false.
 export DO_UGWP_V1_OROG_ONLY=.false.