A Brief Introduction to the Global Ocean Reanalysis (GLORe)

A GLobal Ocean Reanalysis (GLORe) system for climate monitoring and predictions is configured based on MOM6 ocean and CICE6 sea ice models and with the JEDI-SOCA 3DVar data assimilation scheme (developed by JCSDA). The GLORe is an extension of NG-GODAS (Kim et al. 2022), but with modifications to meet the operational requirements for climate monitoring and diagnostics. In this presentation, we will present the latest updates about the GLORe, particularly on the sea ice component. The performance of GLORe will be evaluated by (1) a reanalysis completed for 1979-2022 which assimilated various types of in situ and satellite observations (including in situ temperature and salinity profiles, sea surface temperature, satellite absolute dynamic topography, sea ice concentration); and (2) a set of seasonal hindcasts (1982-2021) using Unified Forecast System (UFS) prototype 8 (UFSp8). Evaluations about the reanalysis indicate that GLORe provides improved temperature and salinity analyses compared to current NOAA operational systems (i.e., GODAS and CFSR); sea ice coverage and volume in GLORe also present more realistic trends and interannual variability than in NG-GODAS. Evaluations about the hindcasts show that the UFSp8 together with GLORe achieves better prediction skill than current operational prediction systems at NOAA (e.g., CFSv2) for both Arctic sea ice and ENSO, and provide further confidence in the credibility of the ocean analysis.