NCAR Resarch Data Archive logo

ERA5 Reanalysis Monthly Means

ds630.1
| DOI: 10.5065/D63B5XW1
 

This historical dataset is recommended for ancillary use only and not as a primary research dataset. It has likely been superseded by a newer, improved dataset.

Abstract:

Please note: Please use ds633.1 to access RDA maintained ERA-5 Monthly Mean data, see ERA5 Reanalysis (Monthly Mean 0.25 Degree Latitude-Longitude Grid), RDA dataset ds633.1. This dataset is no longer being updated, and web access has been removed.

After many years of research and technical preparation, the production of a new ECMWF climate reanalysis to replace ERA-Interim is in progress. ERA5 is the fifth generation of ECMWF atmospheric reanalyses of the global climate, which started with the FGGE reanalyses produced in the 1980s, followed by ERA-15, ERA-40 and most recently ERA-Interim. ERA5 will cover the period January 1950 to near real time, though the first segment of data to be released will span the period 2010-2016.

ERA5 is produced using high-resolution forecasts (HRES) at 31 kilometer resolution (one fourth the spatial resolution of the operational model) and a 62 kilometer resolution ten member 4D-Var ensemble of data assimilation (EDA) in CY41r2 of ECMWF's Integrated Forecast System (IFS) with 137 hybrid sigma-pressure (model) levels in the vertical, up to a top level of 0.01 hPa. Atmospheric data on these levels are interpolated to 37 pressure levels (the same levels as in ERA-Interim). Surface or single level data are also available, containing 2D parameters such as precipitation, 2 meter temperature, top of atmosphere radiation and vertical integrals over the entire atmosphere. The IFS is coupled to a soil model, the parameters of which are also designated as surface parameters, and an ocean wave model. Generally, the data is available at an hourly frequency and consists of analyses and short (18 hour) forecasts, initialized twice daily from analyses at 06 and 18 UTC. Most analyses parameters are also available from the forecasts. There are a number of forecast parameters, e.g. mean rates and accumulations, that are not available from the analyses. Together, the hourly analysis and twice daily forecast parameters form the basis of the monthly means (and monthly diurnal means) found in this dataset.

Improvements to ERA5, compared to ERA-Interim, include use of HadISST.2, reprocessed ECMWF climate data records (CDR), and implementation of RTTOV11 radiative transfer. Variational bias corrections have not only been applied to satellite radiances, but also ozone retrievals, aircraft observations, surface pressure, and radiosonde profiles.

NCAR's Data Support Section (DSS) is performing and supplying a grid transformed version of ERA5, in which variables originally represented as spectral coefficients or archived on a reduced Gaussian grid are transformed to a regular 1280 longitude by 640 latitude N320 Gaussian grid. In addition, DSS is also computing horizontal winds (u-component, v-component) from spectral vorticity and divergence where these are available. Finally, the data is reprocessed into single parameter time series.

Please note: As of November 2017, DSS is also producing a CF 1.6 compliant netCDF-4/HDF5 version of ERA5 for CISL RDA at NCAR. The netCDF-4/HDF5 version is the de facto RDA ERA5 online data format. The GRIB1 data format is only available via NCAR's High Performance Storage System (HPSS). We encourage users to evaluate the netCDF-4/HDF5 version for their work, and to use the currently existing GRIB1 files as a reference and basis of comparison. To ease this transition, there is a one-to-one correspondence between the netCDF-4/HDF5 and GRIB1 files, with as much GRIB1 metadata as possible incorporated into the attributes of the netCDF-4/HDF5 counterpart.

Temporal Range:
2008-01-01 00:00 +0000 to 2017-12-31 23:00 +0000 (Entire dataset) Period details by dataset product
Updates:
Monthly
Variables:
Air Temperature Albedo Albedo Cloud Frequency
Cloud Liquid Water/Ice Convection Convergence Dew Point Temperature
Geopotential Height Heat Flux Humidity Ice Extent
Planetary Boundary Layer Height Sea Level Pressure Sea Surface Temperature Skin Temperature
Snow Density Snow Depth Snow/Ice Temperature Snow/Ice Temperature
Soil Classification Soil Moisture/Water Content Soil Temperature Surface Pressure
Surface Roughness Surface Winds Terrain Elevation Total Precipitable Water
Tropospheric Ozone Upper Air Temperature Upper Level Winds Vegetation Cover
Vegetation Species Vertical Wind Velocity/Speed Vorticity Water Vapor
Wind Stress
GRIB parameter table: HTML | XML
Vertical Levels:
See the detailed metadata for level information.
Data Types:
Grid
Spatial Coverage:
Longitude Range: Westernmost=180W Easternmost=180E
Latitude Range: Southernmost=89.785S Northernmost=89.785N Detailed coverage information
Data Contributors:
ECMWF
European Centre for Medium-Range Weather Forecasts
Publications:
Malardel, S., N. Wedi, W. Deconinck, M. Diamantakis, C. Kuhnlein, G. Mozdzynski, M. Hamrud, and P. Smolarkiewicz, 2015: A new grid for the IFS. Newsletter No. 146 - Winter 2015/16, ECMWF, 6 pp.

Total Volume:
5.05 TB (Entire dataset) Volume details by dataset product
Data Formats:
Related RDA Datasets:
 - 
ERA-Interim Project
 - 
ERA-Interim Project, Monthly Means
 - 
ERA-Interim Project, Single Parameter 6-Hourly Surface Analysis and Surface Forecast Time Series
 - 
JRA-55: Japanese 55-year Reanalysis, Daily 3-Hourly and 6-Hourly Data
 - 
JRA-55: Japanese 55-year Reanalysis, Monthly Means and Variances
 - 
ERA5 Reanalysis
 - 
ERA5 Reanalysis (0.25 Degree Latitude-Longitude Grid)
 - 
ERA5 Reanalysis (Monthly Mean 0.25 Degree Latitude-Longitude Grid)
More Details:
View a more detailed summary of the data, including specific date ranges and locations by parameter
Metadata Record:
Data License:
Citation counts are compiled through information provided by publicly-accessible APIs according to the guidelines developed through the https://makedatacount.org/ project. If journals do not provide citation information to these publicly-accessible services, then this citation information will not be included in RDA citation counts. Additionally citations that include dataset DOIs are the only types included in these counts, so legacy citations without DOIs, references found in publication acknowledgements, or references to a related publication that describes a dataset will not be included in these counts.