Assessment of Météo-France current seasonal forecasting system S7 and outlook on the upcoming S8
<p>In the framework of the EU <span>C</span><span>opernicus</span> <span>Climate Change Service </span><span>(</span>C3S) program, a new coupled system has been developed at M&#233;t&#233;o-France (MF) to carry out seasonal forecasts at a 7-month range. This system (called S7) is in operation in real time since October 2019. S7 is based upon the MF coupled climate model CNRM-CM6 used for CMIP6 simulations, in its high resolution configuration: ARPEGE-Climat (Tl359-0.5&#176; l91, including different tuning choices for the physics), NEMO 3.6 (0.25&#176; l75) and the OASIS coupler. The aim of this presentation is twofold.</p><p>First, an assessment of S7 performance will be presented in terms of biases, and both deterministic and probabilistic predictability scores. A comparison with the earlier MF system and the current ECMWF system will be shown.</p><p>Second, incremental updates from S7 to S8, to be in operation in June 2021, will be presented and assessed versus S7. The upgrade includes a larger atmospheric resolution from l91 to l137, together with a coupled initialization strategy to replace the earlier independent atmospheric and oceanic initialization.</p>