_RL exf_outscal_ustress
& , exf_outscal_ustress
fu(i,j,bi,bj) = exf_outscal_ustress*
fu(i,j,bi,bj) = exf_outscal_ustress*ustress(i,j,bi,bj)
& exf_outscal_hflux, exf_outscal_ustress, exf_outscal_vstress,
exf_outscal_ustress = 1. _d 0