This catalogue entry provides monthly mean time series from the global ocean and sea-ice reanalysis ORAS5 (Ocean Reanalysis System 5), with data organised to prioritise temporal access at grid point locations rather than full spatial fields. The dataset enables users to efficiently retrieve long, continuous time series for individual ocean points, supporting analyses of ocean variability and change without the need to download and process large global gridded datasets.
The data originate from the European Centre for Medium-range Weather Forecasts (ECMWF) OCEAN5 ocean analysis–reanalysis system and represent one ensemble member from a five-member ensemble. Reanalysis combines numerical model output with a wide range of observations using data assimilation techniques to produce a temporally and spatially consistent record that respects physical laws. ORAS5 provides gap-free monthly information over the global ocean and sea-ice domain.
The underlying reanalysis is produced using the Nucleus for European Modelling of the Ocean (NEMO) ocean model coupled with the NEMOVAR data assimilation system, which applies a 3D-Var First Guess at Appropriate Time (FGAT) approach. The assimilation incorporates observations of subsurface temperature and salinity, sea-ice concentration, sea-level anomalies, sea surface temperature, and sea surface salinity, ensuring physically consistent estimates of the ocean state through time.
Two production streams are included. The consolidated product uses reanalysis atmospheric forcing (ERA-40 up to 1978 and ERA-Interim from 1979 to 2014) together with reprocessed observations, providing a temporally consistent historical record. The operational product, available from 2015 onward, is updated monthly with a latency of approximately 15 days and uses ECMWF operational atmospheric forcing and near-real-time observations. These two streams balance long-term consistency and near-real-time availability.
The dataset presented here is a regridded subset of ORAS5 (see related datasets) stored in an Analysis-Ready, Cloud-Optimised (ARCO) format, specifically designed for rapid extraction of long time series at individual points. When a requested location does not coincide exactly with a model grid point, the nearest grid point is automatically selected. This design ensures fast response times and minimal data handling overhead, making the dataset well suited for workflows focused on temporal variability, trend analysis, and location-specific diagnostics.
This time-series-oriented access is particularly valuable for users interested in ocean climate indicators, long-term monitoring at fixed locations (e.g. moorings, transects, or regions of interest), and applications where temporal evolution is more important than full spatial coverage, such as validation studies, climate services, and operational monitoring.
ORAS5 is produced by ECMWF and funded by the Copernicus Climate Change Service (C3S).
The data originate from the European Centre for Medium-range Weather Forecasts (ECMWF) OCEAN5 ocean analysis–reanalysis system and represent one ensemble member from a five-member ensemble. Reanalysis combines numerical model output with a wide range of observations using data assimilation techniques to produce a temporally and spatially consistent record that respects physical laws. ORAS5 provides gap-free monthly information over the global ocean and sea-ice domain.
The underlying reanalysis is produced using the Nucleus for European Modelling of the Ocean (NEMO) ocean model coupled with the NEMOVAR data assimilation system, which applies a 3D-Var First Guess at Appropriate Time (FGAT) approach. The assimilation incorporates observations of subsurface temperature and salinity, sea-ice concentration, sea-level anomalies, sea surface temperature, and sea surface salinity, ensuring physically consistent estimates of the ocean state through time.
Two production streams are included. The consolidated product uses reanalysis atmospheric forcing (ERA-40 up to 1978 and ERA-Interim from 1979 to 2014) together with reprocessed observations, providing a temporally consistent historical record. The operational product, available from 2015 onward, is updated monthly with a latency of approximately 15 days and uses ECMWF operational atmospheric forcing and near-real-time observations. These two streams balance long-term consistency and near-real-time availability.
The dataset presented here is a regridded subset of ORAS5 (see related datasets) stored in an Analysis-Ready, Cloud-Optimised (ARCO) format, specifically designed for rapid extraction of long time series at individual points. When a requested location does not coincide exactly with a model grid point, the nearest grid point is automatically selected. This design ensures fast response times and minimal data handling overhead, making the dataset well suited for workflows focused on temporal variability, trend analysis, and location-specific diagnostics.
This time-series-oriented access is particularly valuable for users interested in ocean climate indicators, long-term monitoring at fixed locations (e.g. moorings, transects, or regions of interest), and applications where temporal evolution is more important than full spatial coverage, such as validation studies, climate services, and operational monitoring.
ORAS5 is produced by ECMWF and funded by the Copernicus Climate Change Service (C3S).
Interval
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Portal
Climate Data Store
Product Family
Data
Product Type
Reanalysis
Provider
Copernicus C3S
ECMWF
Spatial Coverage
Global
Temporal Coverage
Past
Variable Domain
Ocean (physics)