TY - SLIDE KW - Symposium KW - 4D-Var AU - Massimo Bonavita 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 - Advancing data assimilation in global NWP: the ECMWF perspective ER -