The ECMWF operational ensemble reanalysis–analysis system for ocean and sea ice: a description of the system and assessment

Abstract. The ECMWF OCEAN5 system is a global ocean and sea-ice ensemble of reanalysis and real-time analysis. This paper gives a full description of the OCEAN5 system, with the focus on upgrades of system components with respect to its predecessors, ORAS4 and ORAP5. An important novelty in OCEAN5 is the ensemble generation strategy that includes perturbation of initial conditions and a generic perturbation scheme for observations and forcing fields. Other upgrades include revisions to the a priori bias correction scheme, observation quality control and assimilation method for sea-level anomalies. The OCEAN5 historical reconstruction of the ocean and sea-ice state is the ORAS5 reanalysis, which includes five…

• ES
  European Space Agency

  Award: 4000109872/13/I-NB
• EC
  European Commission

  Awards: 633211, H2020
• H2
  Horizon 2020 Framework Programme

  Award: 633211