Merge branch '333-bug-in-ice-ocean-stress' into 'branch_4.2'

Resolve "bug in ice-ocean stress"

See merge request nemo/nemo!402

src/ICE/iceupdate.F90

@@ -383,8 +383,8 @@ CONTAINS
          zat_v  = ( at_i(ji,jj) * tmask(ji,jj,1) + at_i (ji  ,jj+1  ) * tmask(ji  ,jj+1,1) )  &
             &     / MAX( 1.0_wp , tmask(ji,jj,1) + tmask(ji  ,jj+1,1) )
          !                                                   ! linearized quadratic drag formulation
-         zutau_ice   = 0.5_wp * ( tmod_io(ji,jj) + tmod_io(ji+1,jj) ) * ( u_ice(ji,jj) - pu_oce(ji,jj) )
-         zvtau_ice   = 0.5_wp * ( tmod_io(ji,jj) + tmod_io(ji,jj+1) ) * ( v_ice(ji,jj) - pv_oce(ji,jj) )
+         zutau_ice   = 0.5_wp * ( tmod_io(ji,jj) + tmod_io(ji+1,jj) ) * ( u_ice(ji,jj) - zflagi * pu_oce(ji,jj) )
+         zvtau_ice   = 0.5_wp * ( tmod_io(ji,jj) + tmod_io(ji,jj+1) ) * ( v_ice(ji,jj) - zflagi * pv_oce(ji,jj) )
          !                                                   ! stresses at the ocean surface
          utau(ji,jj) = ( 1._wp - zat_u ) * utau_oce(ji,jj) + zat_u * zutau_ice
          vtau(ji,jj) = ( 1._wp - zat_v ) * vtau_oce(ji,jj) + zat_v * zvtau_ice