1. System

System name (version)ERA5
Date of implementation2016


2. Configuration


Earth system components included in the analysis system

(e.g., ocean, sea-ice, land, etc.)


Horizontal resolution of the model, with indication of grid spacing in km

(for the different Earth system component included in the model)

TL639, 31 km atmosphere

0.36o ocean waves

Number of levels in the different Earth system components

(for the different Earth system component included in the model)

137 levels in the atmosphere
Frequency of the outputs1-hourly
Top of the atmospheric model

1 Pa

Number of analysis cycle per day2
Earliest start date1 January 1940
Integration time stepThe model time step is 12 minutes for the HRES and 20 minutes for the EDA, though occasionally these numbers are adjusted to cope with instabilities
Length and frequency of the longest forecast18 hour forecasts initialised twice daily from analyses at 06 and 18 UTC
Dataset latency

ERA5T 5 days behind real time (preliminary product)

ERA5 2–3 months (final product)

Additional comments:

IFS cycle 41r2 used.


3. Analysis system
Data assimilation method4D-Var
Length of the analysis window12 hours
Number of ensemble members and their resolution10, TL319, 63km

Additional comments:


4. Externally prescribed boundary conditions and their source


Sea surface temperature

January 1949–December 1960, HadISST2.1.0.0 (monthly), 0.25 x 0.25

January 1961–August 2007, HadISST2.1.1.0 (pentad), 0.25 x 0.25

September 2007 onwards, OSTIA, 0.05 x 0.05

Sea-ice

January 1949–December 1960, HadISST2.0.0.0, 0.25 x 0.25

January 1961–December 1978, HadISST2.0.0.0, 0.25 x 0.25

January 1979–August 2007, OSI SAF (409a), 0.25 x 0.25

September 2007 onwards, OSI SAF oper 0.05 x 0.05

Snowin-situ, IMS 2004 onwards
Vegetationprescribed non-time varying tiles, but using seasonally varying LAI
Land use (and its evolution in time)prescribed non-time varying tiles
AerosolsCMIP5 for volcanic and tropospheric sulphate; only seasonal variations for other species
Green House GasesCMIP5
Solar forcingCMIP5, TIM scaling

Additional comments:



5. Details of model
Dynamical core (e.g., semi-Lagrangian)semi-Lagrangian
Grid structureTL639
Hydrostatic or nonhydrostaticHydrostatic
Radiations parameterization

Chapter 2: https://www.ecmwf.int/en/elibrary/79697-ifs-documentation-cy41r2-part-iv-physical-processes

Boundary layer parameterizationChapter 3: https://www.ecmwf.int/en/elibrary/79697-ifs-documentation-cy41r2-part-iv-physical-processes
Convection parameterizationChapter 6: https://www.ecmwf.int/en/elibrary/79697-ifs-documentation-cy41r2-part-iv-physical-processes
Cloud parameterizationChapter 7: https://www.ecmwf.int/en/elibrary/79697-ifs-documentation-cy41r2-part-iv-physical-processes
Land surface parameterization

Chapter 8: https://www.ecmwf.int/en/elibrary/79697-ifs-documentation-cy41r2-part-iv-physical-processes

Land surface scheme: HTESSEL, Balsamo et al., 2009

Other relevant details:

Soil moisture DA: SEKF

Snow DA: 2D-OI

Radiative transfer model: RTTOVv11

Full details of cycle 41r2: Detailed information of implementation of IFS cycle 41r2

Detailed updated documentation on ERA5: ERA5: data documentation



6. Further information
Operational contact point

Hans Hersbach, hans.hersbach@ecmwf.int

URL of the technical note/ reference paper

Hersbach et al. (2020) https://rmets.onlinelibrary.wiley.com/doi/full/10.1002/qj.3803

DOI: 10.1002/qj.3803

URL for list of productshttps://cds.climate.copernicus.eu/datasets?q=era5



7. Observational data used
URL with the list of observational data used in the reanalysis
DOI of data product if available


Other sources for data access, if available



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