diff --git a/mediator/med_phases_aofluxes_mod.F90 b/mediator/med_phases_aofluxes_mod.F90
index dcb73692..7c27abce 100644
--- a/mediator/med_phases_aofluxes_mod.F90
+++ b/mediator/med_phases_aofluxes_mod.F90
@@ -1647,6 +1647,8 @@ subroutine set_aoflux_in_pointers(fldbun_a, fldbun_o, aoflux_in, lsize, xgrid, r
     if (FB_fldchk(fldbun_a, 'Sa_pslv', rc=rc)) then
        call fldbun_getfldptr(fldbun_a, 'Sa_pslv', aoflux_in%psfc, xgrid=xgrid, rc=rc)
        if (chkerr(rc,__LINE__,u_FILE_u)) return
+    else
+       allocate(aoflux_in%psfc(lsize))
     end if
 
     ! if either density or potential temperature are computed, will need bottom level pressure