Introduction
Here we document the ERA5 dataset, which, eventually, will cover the period from January 1950 onwards. Complete ERA5 data released so far covers the period from 1979 and continues to be extended forward in near real time. For up to date information on ERA5, please consult the C3S Announcements on the Copernicus user forum.
ERA5 is produced using 4D-Var data assimilation and model forecasts in CY41R2 of the ECMWF Integrated Forecast System (IFS), with 137 hybrid sigma/pressure (model) levels in the vertical and the top level at 0.01 hPa. Atmospheric data are available on these levels and they are also interpolated to 37 pressure, 16 potential temperature and 1 potential vorticity level(s) by FULL-POS in the IFS. "Surface or single level" data are also available, containing 2D parameters such as precipitation, top of atmosphere radiation and vertical integrals over the entire depth of the atmosphere. The atmospheric model in the IFS is coupled to a land-surface model (HTESSEL), which produces parameters such as 2m temperature and soil temperatures, and an ocean wave model (WAM), the parameters of which are also designated as surface or single level parameters.
The ERA5 dataset contains one (hourly, 31 km) high resolution realisation (referred to as "reanalysis" or "HRES") and a reduced resolution ten member ensemble (referred to as "ensemble" or "EDA"). Generally, the data are available at a sub-daily and monthly frequency and consist of analyses and short (18 hour) forecasts, initialised twice daily from analyses at 06 and 18 UTC. Most analysed parameters are also available from the forecasts. There are a number of forecast parameters, e.g. mean rates/fluxes and accumulations, that are not available from the analyses.
The data are archived in the ECMWF data archive (MARS) and a pertinent sub-set of the data, interpolated to a regular latitude/longitude grid, has been copied to the C3S Climate Data Store (CDS) disks. On the CDS disks, where single level and pressure level data are available, analyses are provided rather than forecasts, unless the parameter is only available from the forecasts.
ERA5.1 is a re-run of ERA5, for the years 2000 to 2006 only, and was produced to improve upon the cold bias in the lower stratosphere seen in ERA5 during this period.
An ERA5 back extension 1950-1978 (Preliminary version) has been produced. Although in many other respects the quality is relatively good, this preliminary data does suffer from excessively intense tropical cyclones. This dataset is available as a separate entry in the CDS catalogue (and in MARS) for a short period of time, after which it will be deprecated and replaced by a new updated version which will be accessible through the main ERA5 entry. The main entry currently contains data from 1979 onwards.
Data format
Model level parameters are archived in GRIB2 format. All other parameters are in GRIB1 unless otherwise indicated, see Parameter listings.
In the CDS, there is the option of retrieving the data in netCDF format.
Data update frequency
Initial release data, i.e. data no more than three months behind real time, is called ERA5T. In the event that serious flaws are detected in ERA5T, this data could be different to the final ERA5 data. In practice, though, this will be very unlikely to occur. Based on experience with the production of ERA5 so far (and ERA-Interim in the past), our expectation is that such an event would not occur more than once every few years, if at all. In the unlikely event that such a correction is required, users will be notified as soon as possible.
For the CDS, daily updates are available about 5 days behind real time and monthly mean updates are available about 5 days after the end of the month.
Note: At the moment the timing of the availability of ERA5T data on the CDS on a daily basis can vary. We do not work to a specific target schedule. However, the D-5 data are typically available by 12UTC, but not guaranteed. We are working on reducing the variability of the time of availability, but this may take several months to achieve.
For MARS ERA5 data, monthly updates are available about two months after the month in question.
For GRIB data, ERA5T can be identified by the key expver=0005 in the GRIB header. ERA5 is identified by the key expver=0001.
For netCDF data requests which return just ERA5 or just ERA5T data, there is no means of differentiating between ERA5 and ERA5T data in the resulting netCDF files.
For netCDF data requests which return a mixture of ERA5 and ERA5T data, the origin of the variables (1 or 5) will be identifiable in the resulting netCDF files. See the link for more details.
The IFS and data assimilation
For ERA5, the IFS documentation for CY41R2 should be used.
The 4D-Var data assimilation uses 12 hour windows from 09 UTC to 21 UTC and 21 UTC to 09 UTC (the following day).
The 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.
Data organisation and how to download ERA5
The full ERA5 and ERA5T datasets are held in the ECMWF data archive (MARS) and a pertinent sub-set of these data, interpolated to a regular latitude/longitude grid, has been copied to the C3S Climate Data Store (CDS) disks. ERA5.1 is not available from the CDS disks, but is available from MARS (for advice on using ERA5.1 in conjunction with ERA5, CDS data, see "ERA5: mixing CDS and MARS data" in ERA5: data documentation#Guidelines). On the CDS disks, where most single level and pressure level parameters are available, analyses are provided rather than forecasts, unless the parameter is only available from the forecasts.
ERA5 data on the CDS disks can be downloaded either from the relevant CDS download page or using the CDS API.
Getting data from the CDS disks provides the fastest access to ERA5.
ERA5 data in MARS can be accessed using the CDS API, but access is relatively slow.
Documentation is available on How to download ERA5.
Date and time specification
In MARS: the date and time of the data is specified with three MARS keywords: date, time and (forecast) step. For analyses, step=0 hours so that date and time specify the analysis date/time. For forecasts, date and time specify the forecast start time and step specifies the number of hours since that start time. The combination of date, time and step defines the validity date/time. For analyses, the validity date/time is equal to the analysis date/time.
In the CDS: analyses are provided rather than forecasts, unless the parameter is only available from the forecasts. The date and time of the data is specified using the validity date/time, so step does not need to be specified. For forecasts, steps between 1 and 12 hours have been used to provide data for all the validity times in each 24 hours, see Table 0 below.
Spatial grid
The ERA5 HRES atmospheric data has a resolution of 31km, 0.28125 degrees, and the EDA has a resolution of 63km, 0.5625 degrees. (Depending on the parameter, the data are archived either as spectral coefficients with a triangular truncation of T639 (HRES) and T319 (EDA) or on a reduced Gaussian grid with a resolution of N320 (HRES) and N160 (EDA). These grids are so called "linear grids", sometimes referred to as TL639 (HRES) and TL319 (EDA).)
The wave data are produced and archived on a different grid to that of the atmospheric model, namely a reduced latitude/longitude grid with a resolution of 0.36 degrees (HRES) and 1.0 degrees (EDA).
ERA5 data available from the CDS disks has been pre-interpolated to a regular latitude/longitude grid appropriate for that data.
The article Model grid box and time step might be useful.
Surface elevation datasets used by ERA5
In order to define the surface geopotential in ERA5, the IFS uses surface elevation data interpolated from a combination of SRTM30 and other surface elevation datasets. For more details please see the IFS documentation, Cycle 41r2, Part IV. Physical processes, section 11.2.2 Surface elevation data at 30 arc seconds.
Spatial reference systems
The IFS assumes the Earth is a perfect sphere, but the geodetic latitude/longitude of the surface elevation datasets are used as if they were the spherical latitude/longitude of the IFS.
ECMWF data is referenced in the horizontal with respect to the WGS84 ellipse (which defines the major/minor axes) but in the vertical it is referenced to the Geoid (EGM96).
Earth model
For data in GRIB1 format the earth model is a sphere with radius = 6367.47 km, as defined in the WMO GRIB Edition 1 specifications, Table 7, GDS Octet 17
For data in GRIB2 format the earth model is a sphere with radius = 6371.2290 km, as defined in the WMO GRIB2 specifications, section 2.2.1, Code Table 3.2, Code figure 6.
For data in NetCDF format (i.e. converted from the native GRIB format to NetCDF), the earth model is inherited from the GRIB data.
Temporal frequency
For sub-daily data for the HRES (stream=oper/wave) the analyses (type=an) are available hourly. The short forecasts, run twice daily from 06 and 18 UTC, provide hourly output forecast steps from 0 to 18 hours. For the EDA, the sub-daily non-wave data (stream=enda) are available every 3 hours but the sub-daily wave data (stream=ewda) are available hourly.
Instantaneous parameters
All the analysed parameters and many of the forecast parameters are described as "instantaneous". Such instantaneous parameters may, or may not, have been averaged in time, to produce monthly means. For more information on what instantaneous means, see Parameters valid at the specified time.
Mean rates/fluxes and accumulations
Such parameters, which are only available from forecasts, have undergone particular types of statistical processing (temporal mean or accumulation, respectively) over a period of time called the processing period. In addition, these parameters may, or may not, have been averaged in time, to produce monthly means.
The accumulations (over the accumulation/processing period) in the short forecasts (from 06 and 18 UTC) of ERA5 are treated differently compared with those in ERA-Interim and operational data (where the accumulations are from the beginning of the forecast to the validity date/time). In the short forecasts of ERA5, the accumulations are since the previous post processing (archiving), so for:
- reanalysis: accumulations are over the hour (the accumulation/processing period) ending at the validity date/time
- ensemble: accumulations are over the 3 hours (the accumulation/processing period) ending at the validity date/time
- Monthly means (of daily means, stream=moda/edmo): accumulations have been scaled to have an "effective" processing period of one day, see section Monthly means
Mean rate/flux parameters in ERA5 (e.g. Table 4 for surface and single levels) provide similar information to accumulations (e.g. Table 3 for surface and single levels), except they are expressed as temporal means, over the same processing periods, and so have units of "per second".
- Mean rate/flux parameters are easier to deal with than accumulations because the units do not vary with the processing period.
- The mean rate hydrological parameters (e.g. the "Mean total precipitation rate") have units of "kg m-2 s-1", which are equivalent to "mm s-1". They can be multiplied by 86400 seconds (24 hours) to convert to kg m-2 day-1 or mm day-1.
Note that:
- For the CDS time, or validity time, of 00 UTC, the mean rates/fluxes and accumulations are over the hour (3 hours for the EDA) ending at 00 UTC i.e. the mean or accumulation is during the previous day.
- Mean rates/fluxes and accumulations are not available from the analyses.
- Mean rates/fluxes and accumulations at step=0 have values of zero because the length of the processing period is zero.
Minimum/maximum since the previous post processing
The short forecasts of ERA5 contain some surface and single level parameters that are the minimum or maximum value since the previous post processing (archiving), see Table 5 below. So, for:
- reanalysis: the minimum or maximum values are in the hour (the processing period) ending at the validity date/time
- ensemble: the minimum or maximum values are in the 3 hours (the processing period) ending at the validity date/time
Wave spectra
The ERA5 wave model uses wave spectra with 24 directions and 30 frequencies (see "2D wave spectra (single)", Table 7),
Monthly means
In addition to the sub-daily data, most parameters are also available as monthly means. For the surface and single level parameters, there are some exceptions which are listed in Table 8.
Monthly means are available in two forms:
- Synoptic monthly means, for each particular time and forecast step (stream=mnth/wamo/edmm/ewmm) - in the CDS, referred to as "monthly averaged by hour of day".
- Monthly means (of daily means, stream=moda/wamd/edmo/ewmo) for the month as a whole - in the CDS, referred to as "monthly averaged". These monthly means are created from all the hourly (3 hourly for the ensemble) data in the month.
Monthly means for:
- forecast parameters are created using the first 12 hours of the twice daily short forecasts (beginning at 06 and 18 UTC).
- analysis and instantaneous forecast parameters are created from data with a validity time in the month, between 00 and 23 UTC, which excludes the time 00 UTC on the first day of the following month.
- accumulation and mean rate/flux forecast parameters are created from data with processing periods that fall within the month.
- monthly means of daily means, for accumulations and mean rates/fluxes are created from contiguous data with processing periods spanning from 00 UTC on the first day of the month to 00 UTC on the first day of the following month i.e. they are accumulations or mean rates/fluxes for the complete, whole month.
The accumulations in monthly means (of daily means, stream=moda/edmo) have been scaled to have an "effective" processing period of one day, so for accumulations in these streams:
- The hydrological parameters have effective units of "m of water per day" and so they should be multiplied by 1000 to convert to kgm-2day-1 or mmday-1.
- The energy (turbulent and radiative) and momentum fluxes should be divided by 86400 seconds (24 hours) to convert to the commonly used units of Wm-2 and Nm-2, respectively.
Ensemble means and standard deviations
For the EDA sub-daily data (stream=enda/ewda), compared with HRES sub-daily data (stream=oper/wave), there are also ensemble means and standard deviations (type=em/es).
Ensemble standard deviation is often referred to as ensemble spread and is calculated as the standard deviation of the 10-members in the ensemble (i.e., including the control). It is not the sample stdv, so we divide by 10 rather than 9 (N-1).
Ensemble means and standard deviations contain analysed parameters when step=0, otherwise they contain forecast parameters. However, only surface and pressure level data (levtype=sfc/pl) contain forecast steps beyond 3 hours. There are no monthly means for ensemble means and standard deviations.
Level listings
Pressure levels: 1000/975/950/925/900/875/850/825/800/775/750/700/650/600/550/500/450/400/350/300/250/225/200/175/150/125/100/70/50/30/20/10/7/5/3/2/1
Potential temperature levels: 265/275/285/300/315/320/330/350/370/395/430/475/530/600/700/850
Potential vorticity level: 2000
Model levels: 1/to/137, which are described at https://www.ecmwf.int/en/forecasts/documentation-and-support/137-model-levels. The model levels are hybrid pressure/sigma. See the documentation of the underlying model, ECMWF's IFS, cycle 41R2, Part III. Dynamics and numerical procedures, Chapter 2 Basic equations and discretisation.
Parameter listings
Tables 1-6 below describe the surface and single level parameters (levtype=sfc), Table 7 describes wave parameters, Table 8 describes the monthly mean exceptions for surface and single level and wave parameters and Tables 9-13 describe upper air parameters on various levtypes.
Information on all ECMWF parameters (e.g. columns shortName and paramId) is available from the ECMWF parameter database
Table 1: surface and single level parameters: invariants (in time)
(stream=oper/enda/mnth/moda/edmm/edmo, levtype=sfc)
count | name | units | Variable name in CDS | shortName | paramId | an | fc |
---|---|---|---|---|---|---|---|
1 | (0 - 1) | lake_cover | cl | 26 | x | x | |
2 | m | lake_depth | dl | 228007 | x | x | |
3 | (0 - 1) | low_vegetation_cover | cvl | 27 | x | ||
4 | (0 - 1) | high_vegetation_cover | cvh | 28 | x | ||
5 | ~ | type_of_low_vegetation | tvl | 29 | x | ||
6 | ~ | type_of_high_vegetation | tvh | 30 | x | ||
7 | ~ | soil_type | slt | 43 | x | ||
8 | m | standard_deviation_of_filtered_subgrid_orography | sdfor | 74 | x | ||
9 | m**2 s**-2 | geopotential | z | 129 | x | x | |
10 | ~ | standard_deviation_of_orography | sdor | 160 | x | ||
11 | ~ | anisotropy_of_sub_gridscale_orography | isor | 161 | x | ||
12 | radians | angle_of_sub_gridscale_orography | anor | 162 | x | ||
13 | ~ | slope_of_sub_gridscale_orography | slor | 163 | x | ||
14 | (0 - 1) | land_sea_mask | lsm | 172 | x | x |
1Soil type (texture) determines the saturation, field capacity and permanent wilting point at all the soil levels, see Table 8.9 in Chapter 8 Surface parametrization, Part IV Physical Processes of the IFS documentation (CY41R2 for ERA5).
Table 2: surface and single level parameters: instantaneous
(stream=oper/enda/mnth/moda/edmm/edmo, levtype=sfc)
count | name | units | Variable name in CDS | shortName | paramId | an | fc |
---|---|---|---|---|---|---|---|
1 | J kg**-1 | convective_inhibition | cin | 228001 | x | ||
2 | m s**-1 | friction_velocity | zust | 228003 | x | ||
3 | K | lake_mix_layer_temperature | lmlt | 228008 | x | x | |
4 | m | lake_mix_layer_depth | lmld | 228009 | x | x | |
5 | K | lake_bottom_temperature | lblt | 228010 | x | x | |
6 | K | lake_total_layer_temperature | ltlt | 228011 | x | x | |
7 | dimensionless | lake_shape_factor | lshf | 228012 | x | x | |
8 | K | lake_ice_temperature | lict | 228013 | x | x | |
9 | m | lake_ice_depth | licd | 228014 | x | x | |
10 | (0 - 1) | uv_visible_albedo_for_direct_radiation | aluvp | 15 | x | x | |
11 | Minimum vertical gradient of refractivity inside trapping layer | m**-1 | minimum_vertical_gradient_of_refractivity_inside_trapping_layer | dndzn | 228015 | x | |
12 | (0 - 1) | uv_visible_albedo_for_diffuse_radiation | aluvd | 16 | x | x | |
13 | Mean vertical gradient of refractivity inside trapping layer | m**-1 | mean_vertical_gradient_of_refractivity_inside_trapping_layer | dndza | 228016 | x | |
14 | (0 - 1) | near_ir_albedo_for_direct_radiation | alnip | 17 | x | x | |
15 | m | duct_base_height | dctb | 228017 | x | ||
16 | (0 - 1) | near_ir_albedo_for_diffuse_radiation | alnid | 18 | x | x | |
17 | m | trapping_layer_base_height | tplb | 228018 | x | ||
18 | m | trapping_layer_top_height | tplt | 228019 | x | ||
19 | m | cloud_base_height | cbh | 228023 | x | ||
20 | m | deg0l | 228024 | x | |||
21 | m s**-1 | instantaneous_10m_wind_gust | i10fg | 228029 | x | ||
22 | (0 - 1) | sea-ice_cover | ci | 31 | x | x | |
23 | (0 - 1) | snow_albedo | asn | 32 | x | x | |
24 | kg m**-3 | snow_density | rsn | 33 | x | x | |
25 | K | sea_surface_temperature | sst | 34 | x | x | |
26 | K | ice_temperature_layer_1 | istl1 | 35 | x | x | |
27 | K | ice_temperature_layer_2 | istl2 | 36 | x | x | |
28 | K | ice_temperature_layer_3 | istl3 | 37 | x | x | |
29 | K | ice_temperature_layer_4 | istl4 | 38 | x | x | |
30 | m**3 m**-3 | volumetric_soil_water_layer_1 | swvl1 | 39 | x | x | |
31 | m**3 m**-3 | volumetric_soil_water_layer_2 | swvl2 | 40 | x | x | |
32 | m**3 m**-3 | volumetric_soil_water_layer_3 | swvl3 | 41 | x | x | |
33 | m**3 m**-3 | volumetric_soil_water_layer_4 | swvl4 | 42 | x | x | |
34 | J kg**-1 | convective_available_potential_energy | cape | 59 | x | x | |
35 | m**2 m**-2 | leaf_area_index_low_vegetation | lai_lv | 66 | x | x | |
36 | m**2 m**-2 | leaf_area_index_high_vegetation | lai_hv | 67 | x | x | |
37 | m s**-1 | 10m_u-component_of_neutral_wind | u10n | 228131 | x | x | |
38 | m s**-1 | 10m_v-component_of_neutral_wind | v10n | 228132 | x | x | |
39 | Pa | surface_pressure | sp | 134 | x | x | |
40 | K | soil_temperature_level_1 | stl1 | 139 | x | x | |
41 | m of water equivalent | snow_depth | sd | 141 | x | x | |
42 | ~ | charnock | chnk | 148 | x | x | |
43 | Pa | mean_sea_level_pressure | msl | 151 | x | x | |
44 | m | boundary_layer_height | blh | 159 | x | x | |
45 | (0 - 1) | total_cloud_cover | tcc | 164 | x | x | |
46 | m s**-1 | 10m_u-component_of_wind | 10u | 165 | x | x | |
47 | m s**-1 | 10m_v-component_of_wind | 10v | 166 | x | x | |
48 | K | 2m_temperature | 2t | 167 | x | x | |
49 | K | 2m_dewpoint_temperature | 2d | 168 | x | x | |
50 | K | soil_temperature_level_2 | stl2 | 170 | x | x | |
51 | K | soil_temperature_level_3 | stl3 | 183 | x | x | |
52 | (0 - 1) | low_cloud_cover | lcc | 186 | x | x | |
53 | (0 - 1) | medium_cloud_cover | mcc | 187 | x | x | |
54 | (0 - 1) | high_cloud_cover | hcc | 188 | x | x | |
55 | m of water equivalent | skin_reservoir_content | src | 198 | x | x | |
56 | (0 - 1) | instantaneous_large_scale_surface_precipitation_fraction | ilspf | 228217 | x | ||
57 | kg m**-2 s**-1 | convective_rain_rate | crr | 228218 | x | ||
58 | kg m**-2 s**-1 | large_scale_rain_rate | lsrr | 228219 | x | ||
59 | kg m**-2 s**-1 | convective_snowfall_rate_water_equivalent | csfr | 228220 | x | ||
60 | kg m**-2 s**-1 | large_scale_snowfall_rate_water_equivalent | lssfr | 228221 | x | ||
61 | N m**-2 | instantaneous_eastward_turbulent_surface_stress | iews | 229 | x | x | |
62 | N m**-2 | instantaneous_northward_turbulent_surface_stress | inss | 230 | x | x | |
63 | W m**-2 | instantaneous_surface_sensible_heat_flux | ishf | 231 | x | x | |
64 | kg m**-2 s**-1 | instantaneous_moisture_flux | ie | 232 | x | x | |
65 | K | skin_temperature | skt | 235 | x | x | |
66 | K | soil_temperature_level_4 | stl4 | 236 | x | x | |
67 | K | temperature_of_snow_layer | tsn | 238 | x | x | |
68 | (0 - 1) | forecast_albedo | fal | 243 | x | x | |
69 | m | forecast_surface_roughness | fsr | 244 | x | x | |
70 | ~ | forecast_logarithm_of_surface_roughness_for_heat | flsr | 245 | x | x | |
71 | m s**-1 | 100m_u-component_of_wind | 100u | 228246 | x | x | |
72 | m s**-1 | 100m_v-component_of_wind | 100v | 228247 | x | x | |
73 | code table (4.201) | precipitation_type | ptype | 260015 | x | ||
74 | K | k_index | kx | 260121 | x | ||
75 | K | total_totals_index | totalx | 260123 | x |
2GRIB2 format
3Leaf Area Index (LAI) parameters are based on a monthly climatology. Users will only see monthly variability, but not inter-annual variability.
Table 3: surface and single level parameters: accumulations
(stream=oper/enda/mnth/moda/edmm/edmo, levtype=sfc)
count | name | units | Variable name in CDS | shortName | paramId | an | fc |
---|---|---|---|---|---|---|---|
1 | s | large_scale_precipitation_fraction | lspf | 50 | x | ||
2 | J m**-2 | downward_uv_radiation_at_the_surface | uvb | 57 | x | ||
3 | J m**-2 | boundary_layer_dissipation | bld | 145 | x | ||
4 | J m**-2 | surface_sensible_heat_flux | sshf | 146 | x | ||
5 | J m**-2 | surface_latent_heat_flux | slhf | 147 | x | ||
6 | J m**-2 | surface_solar_radiation_downwards | ssrd | 169 | x | ||
7 | J m**-2 | surface_thermal_radiation_downwards | strd | 175 | x | ||
8 | J m**-2 | surface_net_solar_radiation | ssr | 176 | x | ||
9 | J m**-2 | surface_net_thermal_radiation | str | 177 | x | ||
10 | J m**-2 | top_net_solar_radiation | tsr | 178 | x | ||
11 | J m**-2 | top_net_thermal_radiation | ttr | 179 | x | ||
12 | N m**-2 s | eastward_turbulent_surface_stress | ewss | 180 | x | ||
13 | N m**-2 s | northward_turbulent_surface_stress | nsss | 181 | x | ||
14 | N m**-2 s | eastward_gravity_wave_surface_stress | lgws | 195 | x | ||
15 | N m**-2 s | northward_gravity_wave_surface_stress | mgws | 196 | x | ||
16 | J m**-2 | gravity_wave_dissipation | gwd | 197 | x | ||
17 | J m**-2 | top_net_solar_radiation_clear_sky | tsrc | 208 | x | ||
18 | J m**-2 | top_net_thermal_radiation_clear_sky | ttrc | 209 | x | ||
19 | J m**-2 | surface_net_solar_radiation_clear_sky | ssrc | 210 | x | ||
20 | J m**-2 | surface_net_thermal_radiation_clear_sky | strc | 211 | x | ||
21 | J m**-2 | toa_incident_solar_radiation | tisr | 212 | x | ||
22 | kg m**-2 | vertically_integrated_moisture_divergence | vimd | 213 | x | ||
23 | J m**-2 | total_sky_direct_solar_radiation_at_surface | fdir | 228021 | x | ||
24 | J m**-2 | clear_sky_direct_solar_radiation_at_surface | cdir | 228022 | x | ||
25 | J m**-2 | surface_solar_radiation_downward_clear_sky | ssrdc | 228129 | x | ||
26 | J m**-2 | surface_thermal_radiation_downward_clear_sky | strdc | 228130 | x | ||
27 | m | surface_runoff | sro | 8 | x | ||
28 | m | sub_surface_runoff | ssro | 9 | x | ||
29 | m of water equivalent | snow_evaporation | es | 44 | x | ||
30 | m of water equivalent | snowmelt | smlt | 45 | x | ||
31 | m | large_scale_precipitation | lsp | 142 | x | ||
32 | m | convective_precipitation | cp | 143 | x | ||
33 | m of water equivalent | snowfall | sf | 144 | x | ||
34 | m of water equivalent | evaporation | e | 182 | x | ||
35 | m | runoff | ro | 205 | x | ||
36 | m | total_precipitation | tp | 228 | x | ||
37 | m of water equivalent | convective_snowfall | csf | 239 | x | ||
38 | m of water equivalent | large_scale_snowfall | lsf | 240 | x | ||
39 | m | potential_evaporation | pev | 228251 | x |
The accumulations in monthly means of daily means (stream=moda/edmo), see monthly means, have been scaled to have units that include "per day", so for accumulations in these streams:
- Most hydrological parameters are in units of "m of water per day", so these should be multiplied by 1000 to convert to kg m-2 day-1 or mm day-1.
- Energy (turbulent and radiative) and momentum fluxes should be divided by 86400 seconds (24 hours) to convert to the commonly used units of W m-2 and N m-2, respectively.
Table 4: surface and single level parameters: mean rates/fluxes
(stream=oper/enda/mnth/moda/edmm/edmo, levtype=sfc)
count | name | units | Variable name in CDS | shortName | paramId | an | fc |
---|---|---|---|---|---|---|---|
1 | kg m**-2 s**-1 | mean_surface_runoff_rate | msror | 235020 | x | ||
2 | kg m**-2 s**-1 | mean_sub_surface_runoff_rate | mssror | 235021 | x | ||
3 | kg m**-2 s**-1 | mean_snow_evaporation_rate | mser | 235023 | x | ||
4 | kg m**-2 s**-1 | mean_snowmelt_rate | msmr | 235024 | x | ||
5 | Proportion | mean_large_scale_precipitation_fraction | mlspf | 235026 | x | ||
6 | W m**-2 | mean_surface_downward_uv_radiation_flux | msdwuvrf | 235027 | x | ||
7 | kg m**-2 s**-1 | mean_large_scale_precipitation_rate | mlspr | 235029 | x | ||
8 | kg m**-2 s**-1 | mean_convective_precipitation_rate | mcpr | 235030 | x | ||
9 | kg m**-2 s**-1 | mean_snowfall_rate | msr | 235031 | x | ||
10 | W m**-2 | mean_boundary_layer_dissipation | mbld | 235032 | x | ||
11 | W m**-2 | mean_surface_sensible_heat_flux | msshf | 235033 | x | ||
12 | W m**-2 | mean_surface_latent_heat_flux | mslhf | 235034 | x | ||
13 | W m**-2 | mean_surface_downward_short_wave_radiation_flux | msdwswrf | 235035 | x | ||
14 | W m**-2 | mean_surface_downward_long_wave_radiation_flux | msdwlwrf | 235036 | x | ||
15 | W m**-2 | mean_surface_net_short_wave_radiation_flux | msnswrf | 235037 | x | ||
16 | W m**-2 | mean_surface_net_long_wave_radiation_flux | msnlwrf | 235038 | x | ||
17 | W m**-2 | mean_top_net_short_wave_radiation_flux | mtnswrf | 235039 | x | ||
18 | W m**-2 | mean_top_net_long_wave_radiation_flux | mtnlwrf | 235040 | x | ||
19 | N m**-2 | mean_eastward_turbulent_surface_stress | metss | 235041 | x | ||
20 | N m**-2 | mean_northward_turbulent_surface_stress | mntss | 235042 | x | ||
21 | kg m**-2 s**-1 | mean_evaporation_rate | mer | 235043 | x | ||
22 | N m**-2 | mean_eastward_gravity_wave_surface_stress | megwss | 235045 | x | ||
23 | N m**-2 | mean_northward_gravity_wave_surface_stress | mngwss | 235046 | x | ||
24 | W m**-2 | mean_gravity_wave_dissipation | mgwd | 235047 | x | ||
25 | kg m**-2 s**-1 | mean_runoff_rate | mror | 235048 | x | ||
26 | W m**-2 | mean_top_net_short_wave_radiation_flux_clear_sky | mtnswrfcs | 235049 | x | ||
27 | W m**-2 | mean_top_net_long_wave_radiation_flux_clear_sky | mtnlwrfcs | 235050 | x | ||
28 | W m**-2 | mean_surface_net_short_wave_radiation_flux_clear_sky | msnswrfcs | 235051 | x | ||
29 | W m**-2 | mean_surface_net_long_wave_radiation_flux_clear_sky | msnlwrfcs | 235052 | x | ||
30 | W m**-2 | mean_top_downward_short_wave_radiation_flux | mtdwswrf | 235053 | x | ||
31 | kg m**-2 s**-1 | mean_vertically_integrated_moisture_divergence | mvimd | 235054 | x | ||
32 | kg m**-2 s**-1 | mean_total_precipitation_rate | mtpr | 235055 | x | ||
33 | kg m**-2 s**-1 | mean_convective_snowfall_rate | mcsr | 235056 | x | ||
34 | kg m**-2 s**-1 | mean_large_scale_snowfall_rate | mlssr | 235057 | x | ||
35 | W m**-2 | mean_surface_direct_short_wave_radiation_flux | msdrswrf | 235058 | x | ||
36 | W m**-2 | mean_surface_direct_short_wave_radiation_flux_clear_sky | msdrswrfcs | 235059 | x | ||
37 | W m**-2 | mean_surface_downward_short_wave_radiation_flux_clear_sky | msdwswrfcs | 235068 | x | ||
38 | W m**-2 | mean_surface_downward_long_wave_radiation_flux_clear_sky | msdwlwrfcs | 235069 | x | ||
39 | kg m**-2 s**-1 | mean_potential_evaporation_rate | mper | 235070 | x |
The mean rates/fluxes in Table 4 provide similar information to the accumulations in Table 3, except they are expressed as temporal averages, and so have units of "per second". The mean rate hydrological parameters have units of "kg m-2 s-1" and so they can be multiplied by 86400 seconds (24 hours) to convert to kg m-2 day-1 or mm day-1.
Table 5: surface and single level parameters: minimum/maximum
(stream=oper/enda, levtype=sfc)
count | name | units | Variable name in CDS | shortName | paramId | an | fc |
---|---|---|---|---|---|---|---|
1 | m s**-1 | 10m_wind_gust_since_previous_post_processing | 10fg | 49 | x | ||
2 | Maximum temperature at 2 metres since previous post-processing | K | maximum_2m_temperature_since_previous_post_processing | mx2t | 201 | x | |
3 | Minimum temperature at 2 metres since previous post-processing | K | minimum_2m_temperature_since_previous_post_processing | mn2t | 202 | x | |
4 | Maximum total precipitation rate since previous post-processing | kg m**-2 s**-1 | maximum_total_precipitation_rate_since_previous_post_processing | mxtpr | 228226 | x | |
5 | Minimum total precipitation rate since previous post-processing | kg m**-2 s**-1 | minimum_total_precipitation_rate_since_previous_post_processing | mntpr | 228227 | x |
Table 6: surface and single level parameters: vertical integrals and total column: instantaneous
(stream=oper/enda/mnth/moda/edmm/edmo - vertical integrals not available for type=em/es, levtype=sfc
count | name | units | Variable name in CDS | shortName | paramId | an | fc |
---|---|---|---|---|---|---|---|
1 | kg m**-2 | vertical_integral_of_mass_of_atmosphere | vima | 162053 | x | x | |
2 | K kg m**-2 | vertical_integral_of_temperature | vit | 162054 | x | x | |
3 | J m**-2 | vertical_integral_of_kinetic_energy | vike | 162059 | x | x | |
4 | J m**-2 | vertical_integral_of_thermal_energy | vithe | 162060 | x | x | |
5 | J m**-2 | vertical_integral_of_potential_and_internal_energy | vipie | 162061 | x | x | |
6 | J m**-2 | vertical_integral_of_potential_internal_and_latent_energy | vipile | 162062 | x | x | |
7 | J m**-2 | vertical_integral_of_total_energy | vitoe | 162063 | x | x | |
8 | W m**-2 | vertical_integral_of_energy_conversion | viec | 162064 | x | x | |
9 | kg m**-1 s**-1 | vertical_integral_of_eastward_mass_flux | vimae | 162065 | x | x | |
10 | kg m**-1 s**-1 | vertical_integral_of_northward_mass_flux | viman | 162066 | x | x | |
11 | W m**-1 | vertical_integral_of_eastward_kinetic_energy_flux | vikee | 162067 | x | x | |
12 | W m**-1 | vertical_integral_of_northward_kinetic_energy_flux | viken | 162068 | x | x | |
13 | W m**-1 | vertical_integral_of_eastward_heat_flux | vithee | 162069 | x | x | |
14 | W m**-1 | vertical_integral_of_northward_heat_flux | vithen | 162070 | x | x | |
15 | kg m**-1 s**-1 | vertical_integral_of_eastward_water_vapour_flux | viwve | 162071 | x | x | |
16 | kg m**-1 s**-1 | vertical_integral_of_northward_water_vapour_flux | viwvn | 162072 | x | x | |
17 | W m**-1 | vertical_integral_of_eastward_geopotential_flux | vige | 162073 | x | x | |
18 | W m**-1 | vertical_integral_of_northward_geopotential_flux | vign | 162074 | x | x | |
19 | W m**-1 | vertical_integral_of_eastward_total_energy_flux | vitoee | 162075 | x | x | |
20 | W m**-1 | vertical_integral_of_northward_total_energy_flux | vitoen | 162076 | x | x | |
21 | kg m**-1 s**-1 | vertical_integral_of_eastward_ozone_flux | vioze | 162077 | x | x | |
22 | kg m**-1 s**-1 | vertical_integral_of_northward_ozone_flux | viozn | 162078 | x | x | |
23 | kg m**-2 s**-1 | vertical_integral_of_divergence_of_cloud_liquid_water_flux | vilwd | 162079 | x | x | |
24 | kg m**-2 s**-1 | vertical_integral_of_divergence_of_cloud_frozen_water_flux | viiwd | 162080 | x | x | |
25 | kg m**-2 s**-1 | vertical_integral_of_divergence_of_mass_flux | vimad | 162081 | x | x | |
26 | W m**-2 | vertical_integral_of_divergence_of_kinetic_energy_flux | viked | 162082 | x | x | |
27 | W m**-2 | vertical_integral_of_divergence_of_thermal_energy_flux | vithed | 162083 | x | x | |
28 | kg m**-2 s**-1 | vertical_integral_of_divergence_of_moisture_flux | viwvd | 162084 | x | x | |
29 | W m**-2 | vertical_integral_of_divergence_of_geopotential_flux | vigd | 162085 | x | x | |
30 | W m**-2 | vertical_integral_of_divergence_of_total_energy_flux | vitoed | 162086 | x | x | |
31 | kg m**-2 s**-1 | vertical_integral_of_divergence_of_ozone_flux | viozd | 162087 | x | x | |
32 | kg m**-1 s**-1 | vertical_integral_of_eastward_cloud_liquid_water_flux | vilwe | 162088 | x | x | |
33 | kg m**-1 s**-1 | vertical_integral_of_northward_cloud_liquid_water_flux | vilwn | 162089 | x | x | |
34 | kg m**-1 s**-1 | vertical_integral_of_eastward_cloud_frozen_water_flux | viiwe | 162090 | x | x | |
35 | kg m**-1 s**-1 | vertical_integral_of_northward_cloud_frozen_water_flux | viiwn | 162091 | x | x | |
36 | kg m**-2 s**-1 | vertical_integral_of_mass_tendency | vimat | 162092 | x | ||
37 | kg m**-2 | total_column_cloud_liquid_water | tclw | 78 | x | x | |
38 | kg m**-2 | total_column_cloud_ice_water | tciw | 79 | x | x | |
39 | kg m**-2 | total_column_supercooled_liquid_water | tcslw | 228088 | x | ||
40 | kg m**-2 | total_column_rain_water | tcrw | 228089 | x | x | |
41 | kg m**-2 | total_column_snow_water | tcsw | 228090 | x | x | |
42 | kg m**-2 | total_column_water | tcw | 136 | x | x | |
43 | kg m**-2 | total_column_water_vapour | tcwv | 137 | x | x | |
44 | kg m**-2 | total_column_ozone | tco3 | 206 | x | x |
Table 7: wave parameters: instantaneous
(stream=wave/ewda/wamo/wamd/ewmm/ewmo)
count | name | units | Variable name in CDS | shortName | paramId | an | fc |
---|---|---|---|---|---|---|---|
1 | m | significant_wave_height_of_first_swell_partition | swh1 | 140121 | x | x | |
2 | degrees | mean_wave_direction_of_first_swell_partition | mwd1 | 140122 | x | x | |
3 | s | mean_wave_period_of_first_swell_partition | mwp1 | 140123 | x | x | |
4 | m | significant_wave_height_of_second_swell_partition | swh2 | 140124 | x | x | |
5 | degrees | mean_wave_period_of_second_swell_partition | mwd2 | 140125 | x | x | |
6 | s | mean_wave_period_of_second_swell_partition | mwp2 | 140126 | x | x | |
7 | m | significant_wave_height_of_third_swell_partition | swh3 | 140127 | x | x | |
8 | degrees | mean_wave_direction_of_third_swell_partition | mwd3 | 140128 | x | x | |
9 | s | mean_wave_period_of_third_swell_partition | mwp3 | 140129 | x | x | |
10 | dimensionless | wave_spectral_skewness | wss | 140207 | x | x | |
11 | m s**-1 | free_convective_velocity_over_the_oceans | wstar | 140208 | x | x | |
12 | kg m**-3 | air_density_over_the_oceans | rhoao | 140209 | x | x | |
13 | dimensionless | normalized_energy_flux_into_waves | phiaw | 140211 | x | x | |
14 | dimensionless | normalized_energy_flux_into_ocean | phioc | 140212 | x | x | |
15 | dimensionless | normalized_stress_into_ocean | tauoc | 140214 | x | x | |
16 | m s**-1 | u_component_stokes_drift | ust | 140215 | x | x | |
17 | m s**-1 | v_component_stokes_drift | vst | 140216 | x | x | |
18 | s | period_corresponding_to_maximum_individual_wave_height | tmax | 140217 | x | x | |
19 | m | maximum_individual_wave_height | hmax | 140218 | x | x | |
20 | m | model_bathymetry | wmb | 140219 | x | x | |
21 | s | mean_wave_period_based_on_first_moment | mp1 | 140220 | x | x | |
22 | s | mean_zero_crossing_wave_period | mp2 | 140221 | x | x | |
23 | dimensionless | wave_spectral_directional_width | wdw | 140222 | x | x | |
24 | s | mean_wave_period_based_on_first_moment_for_wind_waves | p1ww | 140223 | x | x | |
25 | s | mean_wave_period_based_on_second_moment_for_wind_waves | p2ww | 140224 | x | x | |
26 | dimensionless | wave_spectral_directional_width_for_wind_waves | dwww | 140225 | x | x | |
27 | s | mean_wave_period_based_on_first_moment_for_swell | p1ps | 140226 | x | x | |
28 | s | mean_wave_period_based_on_second_moment_for_wind_waves | p2ps | 140227 | x | x | |
29 | dimensionless | wave_spectral_directional_width_for_swell | dwps | 140228 | x | x | |
30 | m | significant_height_of_combined_wind_waves_and_swell | swh | 140229 | x | x | |
31 | degrees | mean_wave_direction | mwd | 140230 | x | x | |
32 | s | peak_wave_period | pp1d | 140231 | x | x | |
33 | s | mean_wave_period | mwp | 140232 | x | x | |
34 | dimensionless | coefficient_of_drag_with_waves | cdww | 140233 | x | x | |
35 | m | significant_height_of_wind_waves | shww | 140234 | x | x | |
36 | degrees | mean_direction_of_wind_waves | mdww | 140235 | x | x | |
37 | s | mean_period_of_wind_waves | mpww | 140236 | x | x | |
38 | m | significant_height_of_total_swell | shts | 140237 | x | x | |
39 | degrees | mean_direction_of_total_swell | mdts | 140238 | x | x | |
40 | s | mean_period_of_total_swell | mpts | 140239 | x | x | |
41 | dimensionless | mean_square_slope_of_waves | msqs | 140244 | x | x | |
42 | m s**-1 | ocean_surface_stress_equivalent_10m_neutral_wind_speed | wind | 140245 | x | x | |
43 | degrees | ocean_surface_stress_equivalent_10m_neutral_wind_direction | dwi | 140249 | x | x | |
44 | dimensionless | wave_spectral_kurtosis | wsk | 140252 | x | x | |
45 | dimensionless | benjamin_feir_index | bfi | 140253 | x | x | |
46 | dimensionless | wave_spectral_peakedness | wsp | 140254 | x | x | |
47 | m | Not available from the CDS disks | awh | 140246 | x | ||
48 | m | Not available from the CDS disks | acwh | 140247 | x | ||
49 | ~ | Not available from the CDS disks | arrc | 140248 | x | ||
50 | m**2 s radian**-1 | Not available from the CDS disks | 2dfd | 140251 | x |
1for 30 frequencies and 24 directions
Table 8: monthly mean surface and single level and wave parameters: exceptions from Tables 1-7
(stream=mnth/moda/edmm/edmo, levtype=sfc or wamo/wamd/ewmm/ewmo)
count | name | units | Variable name in CDS | shortName | paramId | an | fc |
---|---|---|---|---|---|---|---|
1 | (0 - 1) | uv_visible_albedo_for_direct_radiation | aluvp | 15 | x | no mean | |
2 | (0 - 1) | uv_visible_albedo_for_diffuse_radiation | aluvd | 16 | x | no mean | |
3 | (0 - 1) | near_ir_albedo_for_direct_radiation | alnip | 17 | x | no mean | |
4 | (0 - 1) | near_ir_albedo_for_diffuse_radiation | alnid | 18 | x | no mean | |
5 | N m**-2 s | magnitude of turbulent surface stress | magss | 48 | x | ||
6 | Mean magnitude of turbulent surface stress2 | N m**-2 | mean magnitude of turbulent surface stress | mmtss | 235025 | x | |
7 | m s**-1 | 10m_wind_gust_since_previous_post_processing | 10fg | 49 | no mean | ||
8 | Maximum temperature at 2 metres since previous post-processing | K | maximum_2m_temperature_since_previous_post_processing | mx2t | 201 | no mean | |
9 | Minimum temperature at 2 metres since previous post-processing | K | minimum_2m_temperature_since_previous_post_processing | mn2t | 202 | no mean | |
10 | m s**-1 | 10m wind speed | 10si | 207 | x | x | |
11 | Maximum total precipitation rate since previous post-processing | kg m**-2 s**-1 | maximum_total_precipitation_rate_since_previous_post_processing | mxtpr | 228226 | no mean | |
12 | Minimum total precipitation rate since previous post-processing | kg m**-2 s**-1 | minimum_total_precipitation_rate_since_previous_post_processing | mntpr | 228227 | no mean | |
13 | m | Not available from the CDS disks | awh | 140246 | no mean | ||
14 | m | Not available from the CDS disks | acwh | 140247 | no mean | ||
15 | ~ | Not available from the CDS disks | arrc | 140248 | no mean | ||
16 | m**2 s radian**-1 | Not available from the CDS disks | 2dfd | 140251 | no mean |
1Accumulated parameter
2Mean rate/flux parameter
3Instantaneous parameter
Table 9: pressure level parameters: instantaneous
(stream=oper/enda/mnth/moda/edmm/edmo, levtype=pl)
count | name | units | Variable name in CDS | shortName | paramId | an | fc |
---|---|---|---|---|---|---|---|
1 | K m**2 kg**-1 s**-1 | potential_vorticity | pv | 60 | x | x | |
2 | kg kg**-1 | specific_rain_water_content | crwc | 75 | x | x | |
3 | kg kg**-1 | specific_snow_water_content | cswc | 76 | x | x | |
4 | m**2 s**-2 | geopotential | z | 129 | x | x | |
5 | K | temperature | t | 130 | x | x | |
6 | m s**-1 | u_component_of_wind | u | 131 | x | x | |
7 | m s**-1 | v_component_of_wind | v | 132 | x | x | |
8 | kg kg**-1 | specific_humidity | q | 133 | x | x | |
9 | Pa s**-1 | vertical_velocity | w | 135 | x | x | |
10 | s**-1 | vorticity | vo | 138 | x | x | |
11 | s**-1 | divergence | d | 155 | x | x | |
12 | % | relative_humidity | r | 157 | x | x | |
13 | kg kg**-1 | ozone_mass_mixing_ratio | o3 | 203 | x | x | |
14 | kg kg**-1 | specific_cloud_liquid_water_content | clwc | 246 | x | x | |
15 | kg kg**-1 | specific_cloud_ice_water_content | ciwc | 247 | x | x | |
16 | (0 - 1) | fraction_of_cloud_cover | cc | 248 | x | x |
Table 10: potential temperature level parameters: instantaneous
(not available from the CDS disks)
(stream=oper/enda/mnth/moda/edmm/edmo, levtype=pt)
count | name | units | shortName | paramId | an | fc |
---|---|---|---|---|---|---|
1 | m**2 s**-2 | mont | 53 | x | ||
2 | Pa | pres | 54 | x | ||
3 | K m**2 kg**-1 s**-1 | pv | 60 | x | ||
4 | m s**-1 | u | 131 | x | ||
5 | m s**-1 | v | 132 | x | ||
6 | kg kg**-1 | q | 133 | x | ||
7 | s**-1 | vo | 138 | x | ||
8 | s**-1 | d | 155 | x | ||
9 | kg kg**-1 | o3 | 203 | x |
Table 11: potential vorticity level parameters: instantaneous
(not available from the CDS disks)
(stream=oper/enda/mnth/moda/edmm/edmo, levtype=pv)
count | name | units | shortName | paramId | an | fc |
---|---|---|---|---|---|---|
1 | K | pt | 3 | x | ||
2 | Pa | pres | 54 | x | ||
3 | m**2 s**-2 | z | 129 | x | ||
4 | m s**-1 | u | 131 | x | ||
5 | m s**-1 | v | 132 | x | ||
6 | kg kg**-1 | q | 133 | x | ||
7 | kg kg**-1 | o3 | 203 | x |
Table 12: model level parameters: instantaneous
(GRIB2 format)
(not available from the CDS disks)
(stream=oper/enda/mnth/moda/edmm/edmo, levtype=ml)
count | name | units | shortName | paramId | an | fc |
---|---|---|---|---|---|---|
1 | kg kg**-1 | crwc | 75 | x | x | |
2 | kg kg**-1 | cswc | 76 | x | x | |
3 | s**-1 | etadot | 77 | x | x | |
4 | m**2 s**-2 | z | 129 | x | x | |
5 | K | t | 130 | x | x | |
6 | m s**-1 | u | 131 | x | x | |
7 | m s**-1 | v | 132 | x | x | |
8 | kg kg**-1 | q | 133 | x | x | |
9 | Pa s**-1 | w | 135 | x | x | |
10 | s**-1 | vo | 138 | x | x | |
11 | ~ | lnsp | 152 | x | x | |
12 | s**-1 | d | 155 | x | x | |
13 | kg kg**-1 | o3 | 203 | x | x | |
14 | kg kg**-1 | clwc | 246 | x | x | |
15 | kg kg**-1 | ciwc | 247 | x | x | |
16 | (0 - 1) | cc | 248 | x | x |
1Only archived on level=1.
Table 13: model level parameters: mean rates/fluxes
(GRIB2 format)
(not available from the CDS disks)
(stream=oper/enda/mnth/moda/edmm/edmo, levtype=ml)
count | name | units | shortName | paramId | an | fc |
---|---|---|---|---|---|---|
1 | Mean temperature tendency due to short-wave radiation | K s**-1 | mttswr | 235001 | x | |
2 | Mean temperature tendency due to long-wave radiation | K s**-1 | mttlwr | 235002 | x | |
3 | Mean temperature tendency due to short-wave radiation, clear sky | K s**-1 | mttswrcs | 235003 | x | |
4 | Mean temperature tendency due to long-wave radiation, clear sky | K s**-1 | mttlwrcs | 235004 | x | |
5 | Mean temperature tendency due to parametrisations | K s**-1 | mttpm | 235005 | x | |
6 | Mean specific humidity tendency due to parametrisations | kg kg**-1 s**-1 | mqtpm | 235006 | x | |
7 | Mean eastward wind tendency due to parametrisations | m s**-2 | mutpm | 235007 | x | |
8 | Mean northward wind tendency due to parametrisations | m s**-2 | mvtpm | 235008 | x | |
9 | Mean updraught mass flux1 | kg m**-2 s**-1 | mumf | 235009 | x | |
10 | Mean downdraught mass flux1 | kg m**-2 s**-1 | mdmf | 235010 | x | |
11 | Mean updraught detrainment rate | kg m**-3 s**-1 | mudr | 235011 | x | |
12 | Mean downdraught detrainment rate | kg m**-3 s**-1 | mddr | 235012 | x | |
13 | Mean total precipitation flux1 | kg m**-2 s**-1 | mtpf | 235013 | x | |
14 | Mean turbulent diffusion coefficient for heat1 | m**2 s**-1 | mtdch | 235014 | x |
1These parameters provide data for the model half levels - the interfaces of the model layers.
Observations
The observations (satellite and in-situ) used as input into ERA5 are listed below.
Table 14: Satellite Data
Sensor | Satellite | Satellite agency | Data provider+ | Measurement (sensitivities exploited in ERA5 / variables analysed) |
---|---|---|---|---|
Satellite radiances (infrared and microwave) | ||||
AIRS | AQUA | NASA | NOAA | BT (T, humidity and ozone) |
AMSR-2 | GCOM-W1* | JAXA | BT (column water vapour, cloud liquid water, precipitation and ocean surface wind speed) | |
AMSRE | AQUA* | JAXA | BT (column water vapour, cloud liquid water, precipitation and ocean surface wind speed) | |
AMSUA | NOAA-15/16/17/18/19, AQUA, METOP-A/B | NOAA,ESA,EUMETSAT | BT (T) | |
AMSUB | NOAA-15/16/17 | NOAA | BT (humidity) | |
ATMS | NPP | NOAA | BT (T and humidity) | |
CRIS | NPP | NOAA | BT (T, humidity and ozone) | |
HIRS | TIROS-N, NOAA-6 /7/8/9/11/14 | NOAA | BT (T, humidity and ozone) | |
IASI | METOP-A/B | EUMETSAT/ESA | EUMETSAT | BT (T, humidity and ozone) |
GMI | GPM | NASA/JAXA | BT (humidity, column water vapour, cloud liquid water, precipitation, ocean surface wind speed) | |
MHS | NOAA-18/19, METOP-A/B | NOAA, EUMETSAT/ESA | BT (humidity and precipitation) | |
MSU | TIROS-N, NOAA-6 to 12, NOAA-14 | BT (T) | ||
MWHS | FY-3-A/B | NRSCC | BT (humidity) | |
MWHS2 | FY-3-C | CMA | BT (T, humidity and precipitation) | |
MWTS | FY-3A/B | NRSCC | BT (T) | |
MWTS2 | FY-3C | CMA | BT (T) | |
SSM/I | DMSP-08*/10*/11*/13*/14*/15* | US Navy | NOAA,CMSAF* | BT (column water vapour, cloud liquid water, precipitation and ocean surface wind speed) |
SSMIS | DMSP-16/17/18 | US Navy | NOAA | BT (T, humidity, column water vapour, cloud liquid water, precipitation and ocean surface wind speed) |
SSU | TIROS-N, NOAA-6/7/8/9/11/14 | NOAA | BT (T) | |
TMI | TRMM | NASA/JAXA | BT (column water vapour, cloud liquid water, precipitation, ocean surface wind speed) | |
MVIRI | METEOSAT 5/7 | EUMETSAT/ESA | EUMETSAT | BT (water vapour, surface/cloud top T) |
SEVIRI | METEOSAT-8*/9*/10 | EUMETSAT/ESA | EUMETSAT | BT (water vapour, surface/cloud top T) |
GOES IMAGER | GOES-8/9/10/11/12/13/15 | NOAA | CIMMS,NESDIS | BT (water vapour, surface/cloud top T) |
MTSAT IMAGER | MTSAT-1R/MTSAT-2 | JMA | BT (water vapour, surface/cloud top T) | |
AHI | Himawari-8 | JMA | BT (water vapour, surface/cloud top T) | |
Satellite retrievals from radiance data | ||||
MVIRI | METEOSAT-2*/3*/4*/5*/7* | EUMETSAT/ESA | EUMETSAT | wind vector |
SEVIRI | METEOSAT-8*/9*/10 | EUMETSAT/ESA | EUMETSAT | wind vector |
GOES IMAGER | GOES-4-6/8*/9*/10*/11*/12*/13*/15* | NOAA | CIMMS*,NESDIS | wind vector |
GMS IMAGER | GMS-1*/2/3*/4*/5* | JMA | wind vector | |
MTSAT IMAGER | MTSAT-1R*/MTSAT2 | JMA | wind vector | |
AHI | Himawari-8 | JMA | JMA | wind vector |
AVHRR | NOAA-7 /9/10/11/12/14 to 18, METOP-A | NOAA | CIMMS,EUMETSAT | wind vector |
MODIS | AQUA/TERRA | NASA | NESDIS,CIMMS | wind vector |
GOME | ERS-2* | ESA | Ozone | |
GOME-2 | METOP*-A/B | ESA/EUMETSAT | Ozone | |
MIPAS | ENVISAT* | ESA | Ozone | |
MLS | EOS-AURA* | NASA | Ozone | |
OMI | EOS-AURA* | NASA | Ozone | |
SBUV,SBUV-2 | NIMBUS-7*,NOAA*9/11/14/16/17/18/19 | NOAA | NASA | Ozone |
SCIAMACHY | ENVISAT* | ESA | Ozone | |
TOMS | NIMBUS-7*,METEOR-3-5,ADEOS-1*,EARTH PROBE | NASA | Ozone | |
Satellite GPS-Radio Occultation data | ||||
BlackJack | CHAMP,GRACE*-A/B,SAC-C* | DLR,NASA/DLR,NASA/COMAE | GFZ,UCAR* | Bending angle |
GRAS | METOP-A/B | EUMETSAT/ESA | EUMETSAT | Bending angle |
IGOR | TerraSAR-X*, TanDEM-X, COSMIC*-1 to 6 | NSPO/NOAA | GFZ,UCAR* | Bending angle |
Satellite scatterometer data | ||||
AMI | ERS-1,ERS-2 | ESA | Backscatter sigma0, soil moisture | |
ASCAT | METOP-A/B* | EUMETSAT/ESA | EUMETSAT/TU Wien | Backscatter sigma0, soil moisture |
OSCAT | OCEANSAT-2 | ISRO | KNMI | Backscatter sigma0, vector wind |
SEAWINDS | QUIKSCAT | NASA | NASA | Backscatter sigma0 |
Satellite Altimeter data | ||||
RA | ERS-1*/2* | ESA | Wave Height | |
RA-2 | ENVISAT* | ESA | Wave Height | |
Poseidon-2 | JASON-1* | CNES/NASA | CNES | Wave Height |
Poseidon-3 | JASON-2 | CNES/NOAA/NASA/EUMETSAT | NOAA/EUMETSAT | Wave Height |
SIRAL | CRYOSAT-2 | ESA | Wave Height | |
AltiKa | SARAL | CNES/ISRO | EUMETSAT | Wave Height |
* reprocessed dataset
+ when different than the satellite agency
Table 15: In-situ data, provided by WMO WIS
Dataset name | Observation type | Measurement |
---|---|---|
SYNOP | Land station | Surface Pressure, Temperature, wind, humidity |
METAR | Land station | Surface Pressure, Temperature, wind,humidity |
DRIBU/DRIBU-BATHY/DRIBU-TESAC/BUFR Drifting Buoy | Drifting buoys | 10m-wind, Surface Pressure |
BUFR Moored Buoy | Moored buoys | 10m-wind, Surface Pressure |
SHIP | ship station | Surface Pressure, Temperature, wind, humidity |
Land/ship PILOT | Radiosondes | wind profiles |
American Wind Profiler | Radar | wind profiles |
European Wind Profiler | Radar | wind profiles |
Japanese Wind Profiler | Radar | wind profiles |
TEMP SHIP | Radiosondes | Temperature, wind, humidity profiles |
DROP Sonde | Aircraft-sondes | Temperature, wind profiles |
Land/Mobile TEMP | Radiosondes | Temperature, wind, humidity profiles |
AIREP | Aircraft data | Temperature, wind profiles |
AMDAR | Aircraft data | Temperature, wind profiles |
ACARS | Aircraft data | Temperature, wind profiles, humidity |
WIGOS AMDAR | Aircraft data | Temperature, wind profiles |
Ground based radar | Radar precipitation composites | Rain rates |
Table 16: Snow data
Dataset name | Observation type | Measurement |
---|---|---|
SYNOP | Land station | Snow depth |
Additional national reports | Land station | Snow depth |
NOAA/NESDIS IMS | Merged satellite | Snow cover (NH only) |
Guidelines
The following advice is intended to help users understand particular features of the ERA5 data:
- ERA5: compute pressure and geopotential on model levels, geopotential height and geometric height
- ERA5: How to calculate wind speed and wind direction from u and v components of the wind?
- Sea surface temperature and sea-ice cover (sea ice area fraction), see Table 2 above, are available at the usual times, eg hourly for the HRES, but their content is only updated once daily.
- Mean rates/fluxes and accumulations at step=0 have values of zero because the length of the processing period is zero.
Known issues
Currently, we are aware of these issues with ERA5:
- ERA5 uncertainty: although small values of ensemble spread correctly mark more confident estimates than large values, numerical values are over confident. The spread does give an indication of the relative, random uncertainty in space and time.
ERA5 suffers from an overly strong equatorial mesospheric jet, particularly in the transition seasons.
From 2000 to 2006, ERA5 has a poor fit to radiosonde temperatures in the stratosphere, with a cold bias in the lower stratosphere. In addition, a warm bias higher up persists for much of the period from 1979. The lower stratospheric cold bias was rectified in a re-run for the years 2000 to 2006, called ERA5.1, see "Resolved issues" below.
- Discontinuities in ERA5: ERA5 is produced by several parallel experiments, each for a different period, which are then appended together to create the final product. This can create discontinuities at the transition points.
- The analysed "2 metre temperature" can be larger than the forecast "Maximum temperature at 2 metres since previous post-processing".
- The analysed 10 metre wind speed (derived from the 10 metre wind components) can be larger than the forecast "10 metre wind gust since previous post-processing".
- ERA5 diurnal cycle for near surface winds: the hourly data reveals a mismatch in the analysed near surface wind speed between the end of one assimilation cycle and the beginning of the next (which occurs at 9:00 - 10:00 and 21:00 - 22:00 UTC). This problem mostly occurs in low latitude oceanic regions, though it can also be seen over Europe and the USA. We cannot rectify this problem in the analyses. The forecast near surface winds show much better agreement between the assimilation cycles, at least on average, so if this mismatch is problematic for a particular application, our advice would be to use the forecast winds. The forecast near surface winds are available from MARS, see the section, Data organisation and how to download ERA5.
- ERA5 diurnal cycle for near surface temperature and humidity: some locations do suffer from a mismatch in the analysed values between the end of one assimilation cycle and the beginning of the next, in a similar fashion to that for the near surface winds (see above), but this problem is thought not to be so widespread as that for the near surface winds. The forecast values for near surface temperature and humidity are usually smoother than the analyses, but the forecast low level temperatures suffer from a cold bias over most parts of the globe. The forecast near surface temperature and humidity are available from MARS, see the section Data organisation and how to download ERA5.
- ERA5: large 10m winds: up to a few times per year, the analysed low level winds, eg 10m winds, become very large in a particular location, which varies amongst a few apparently preferred locations. The largest values seen so far are about 300 ms-1.
- ERA5 rain bombs: from time to time, the rainfall (precipitation) can become extremely large in small areas.
- Large values of CAPE: occasionally, the Convective available potential energy in ERA5 is unrealistically large.
- Ship tracks in the SST: prior to September 2007, in the period when HadISST2 was used, ship tracks can be visible in the SST.
- Prior to 2014, the SST was not used over the Great Lakes to nudge the lake model. Consequently, the 2 metre temperature has an annual cycle that is too strong, with temperatures being too cold in winter and too warm in summer.
- ERA5 CDS: wind values are far too low on pressure levels at the poles in the CDS
- The Potential Evaporation field (pev, parameter Id 228251) is largely underestimated over deserts and high-forested areas. This is due to a bug in the code that does not allow transpiration to occur in the situation where there is no low vegetation.
- Wave parameters (Table 7 above) for the three swell partitions: these parameters have been calculated incorrectly. The problem is most evident in the swell partition parameters involving the mean wave period: Mean wave period of first swell partition, Mean wave period of second swell partition and Mean wave period of third swell partition, where the periods are far too long.
- Surface photosynthetically available radiation (PAR) is too low in the version (CY41R2) of the ECMWF Integrated Forecasting System (IFS) used to produce ERA5, so PAR and clear sky PAR have not been published in ERA5. There is a bug in the calculation of PAR, with it being taken from the wrong parts of the spectrum. The shortwave bands include 0.442-0.625 micron, 0.625-0.778 micron and 0.778-1.24 micron. PAR should be coded to be the sum of the radiation in the first of these bands and 0.42 of the second (to account for the fact that PAR is normally defined to stop at 0.7 microns). However, in CY41R2, PAR is in fact calculated from the sum of the second band plus 0.42 of the third. We will try to fix this in a future cycle.
- ERA5 back extension 1950-1978 (Preliminary version): tropical cyclones are too intense
- ERA5 back extension 1950-1978 (Preliminary version): large bias in surface analysis over Australia prior to 1970
- ERA5 back extension 1950-1978 (Preliminary version): the deep soil moisture tends to be too dry
Resolved issues
- ERA5 CDS: incorrect values of U/V on pressure levels in the CDS
ERA5.1 is a re-run of ERA5, for the years 2000 to 2006 only, and was produced to improve upon the cold bias in the lower stratosphere seen in ERA5.
ERA5.1 CDS: If you retrieved ERA5.1 using the CDS API anytime before 20/05/2020 08:00 UTC, for any stream other than oper (i.e. streams: wave, enda, edmo, ewmo, edmm, ewmm, ewda, moda, wamd, mnth, wamo), you will need to request the data again. Prior to this date, stream oper would be delivered regardless of which stream was requested.
- ERA5 CDS: Data corruption
User support
There is a range of user support available for ERA5, including a Knowledge Base (where this article resides), a Forum and a ticketed system for questions - for more information see the C3S Help and Support Page.
How to acknowledge, cite and refer to ERA5
For ERA5 data on the "CDS disks"
All users of data on the Climate Data Store (CDS) disks (using either the web interface or the CDS API) must provide clear and visible attribution to the Copernicus programme and are asked to cite and reference the dataset provider:
- Acknowledge according to the licence to use Copernicus Products.
- Cite each dataset used as indicated on the relevant CDS entries (see link to "Citation" under References on the Overview page of the dataset entry) .
- Throughout the content of your publication, the dataset used is referred to as Author (YYYY)
For complete details, please refer to How to acknowledge, cite and reference data published on the Climate Data Store.
For ERA5 data in MARS,
If you have downloaded ERA5 data in MARS, using either the CDS API ('reanalysis-era5-complete'
or 'reanalysis-era5.
1
-complete' or '
) or via authorised direct access to MARS, please contact the C3S Helpdesk at ECMWF.reanalysis-era5-complete-preliminary-back-extension'
References
Global stratospheric temperature bias and other stratospheric aspects of ERA5 and ERA5.1
Further ERA5 references are available from the ECMWF e-Library.