@misc{80956,
  author = {Frédéric Vitart and Gianpaolo Balsamo and Jean-Raymond Bidlot and Simon Lang and Ivan Tsonevsky and David Richardson and Magdalena Alonso-Balmaseda},
  title = {Use of ERA5 to Initialize Ensemble Re-forecasts},
  abstract = {<p>
  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. &nbsp;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.</p>
},
  year = {2019},
  journal = {ECMWF Technical Memoranda},
  number = {841},
  month = {02/2019},
  publisher = {ECMWF},
  url = {https://www.ecmwf.int/node/18872},
  doi = {10.21957/w8i57wuz6},
  language = {eng},
}