TY - SLIDE KW - Symposium KW - 4D-Var AU - A. Lorenc BT - Symposium: 20 years of 4D-Var at ECMWF C1 - Events DA - 2018 LA - eng PY - 2018 T2 - Symposium: 20 years of 4D-Var at ECMWF TI - A comparision of hybrid variational data assimilation methods in the Met Office global NWP system ER -