This study summarizes the results from re-forecast experiments initialized with ERA5. Results suggest that initializing the re-forecasts from ERA5 instead of ERA Interim improves the extended-range skill scores up to week 4. The use of the ERA5 EDA to perturb the re-forecast initial conditions has been assessed. The ERA5 EDA provides flow-dependent EDA initial perturbations across the re-forecast years instead of the non-flow-dependent perturbations in the current operational set-up. Results show that it is beneficial to use the ERA5 EDA, even if the impact is limited to just the first week of the re-forecasts. Different strategies for land and wave re-forecast initialization have been tested. The consistency of the re-reforecast land surface climatology with real-time forecasts is improved when initializing from ERA5 and, as a consequence, no separate offline land simulation would be needed to initialize the land in the ERA5 reforecasts.
BT - ECMWF Technical Memoranda DA - 02/2019 DO - 10.21957/w8i57wuz6 LA - eng M1 - 841 N2 -This study summarizes the results from re-forecast experiments initialized with ERA5. Results suggest that initializing the re-forecasts from ERA5 instead of ERA Interim improves the extended-range skill scores up to week 4. The use of the ERA5 EDA to perturb the re-forecast initial conditions has been assessed. The ERA5 EDA provides flow-dependent EDA initial perturbations across the re-forecast years instead of the non-flow-dependent perturbations in the current operational set-up. Results show that it is beneficial to use the ERA5 EDA, even if the impact is limited to just the first week of the re-forecasts. Different strategies for land and wave re-forecast initialization have been tested. The consistency of the re-reforecast land surface climatology with real-time forecasts is improved when initializing from ERA5 and, as a consequence, no separate offline land simulation would be needed to initialize the land in the ERA5 reforecasts.
PB - ECMWF PY - 2019 T2 - ECMWF Technical Memoranda TI - Use of ERA5 to Initialize Ensemble Re-forecasts UR - https://www.ecmwf.int/node/18872 ER -