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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 in CY41R2 of ECMWF’s Integrated Forecast System (IFS), with 137 hybrid sigma/pressure (model) levels in the vertical , with 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, 2m temperature, top of atmosphere radiation and vertical integrals over the entire depth of the atmosphere. The IFS is coupled to a soil model, the parameters of which are also designated as surface parameters, and an ocean wave model.
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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.
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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 will be is available as a separate entry in the CDS catalogue (it will be available and in MARS at a later date) 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 fields (see below) are in GRIB2 format. All other fields are in GRIB1, unless otherwise indicated, see Parameter listings.
In the CDS, there is the option of retrieving the data in netCDF format.
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ERA5 data in MARS can be accessed with the CDS API by specifying dataset whereas member state users can access data in MARS by specifying class and expver, according to the following table:
Subdivisions of the data are labelled using the keywords stream, type and levtype: Stream:
Type:
Levtype:
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(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 |
*Soil 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).
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(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 |
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(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 |
Accumulations are described in section Mean rates and accumulations. The accumulations in monthly means of daily means (stream=moda/edmo) have been scaled to have units that include "per day", so for accumulations in these streams:
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(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 in Table 4 provide similar information to the accumulations in Table 3, except that they are expressed as temporal averages instead of accumulations, and so have units of "per second". The hydrological parameters are in 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.
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(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 |
Anchor | ||||
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(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 |
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(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 | m | altimeter_wave_height | awh | 140246 | x | |||||||
44 | m | altimeter_corrected_wave_height | acwh | 140247 | x | |||||||
45 | ~ | altimeter_range_relative_correction | arrc | 140248 | x | |||||||
46 | degrees | ocean_surface_stress_equivalent_10m_neutral_wind_direction | dwi | 140249 | x | x | ||||||
47 | dimensionless | wave_spectral_kurtosis | wsk | 140252 | x | x | ||||||
48 | dimensionless | benjamin_feir_index | bfi | 140253 | x | x | ||||||
49 | dimensionless | wave_spectral_peakedness | wsp | 140254 | x | x | ||||||
50 | m**2 s radian**-1 | 2dfd | 140251* | x |
*for 30 frequencies and 24 directions
...
(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 | magss | 48 | x | |||
6 | Mean magnitude of turbulent surface stress | N m**-2 | 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 | 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 | altimeter_wave_height | awh | 140246 | no mean | ||
14 | m | altimeter_corrected_wave_height | acwh | 140247 | no mean | ||
15 | ~ | altimeter_range_relative_correction | arrc | 140248 | no mean | ||
16 | m**2 s radian**-1 | 2dfd | 140251 | no mean |
Anchor | ||||
---|---|---|---|---|
|
(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 |
Anchor | ||||
---|---|---|---|---|
|
(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 |
Anchor | ||||
---|---|---|---|---|
|
(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 |
Anchor | ||||
---|---|---|---|---|
|
(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 |
*Only archived on level=1.
...
(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 flux* | kg m**-2 s**-1 | mumf | 235009 | x | |
10 | Mean downdraught mass flux* | 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 flux* | kg m**-2 s**-1 | mtpf | 235013 | x | |
14 | Mean turbulent diffusion coefficient for heat* | m**2 s**-1 | mtdch | 235014 | x |
*These parameters provide data for the model half levels, at the interfaces of the model layers.
...
Anchor | ||||
---|---|---|---|---|
|
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
Anchor | ||||
---|---|---|---|---|
|
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 |
Anchor | ||||
---|---|---|---|---|
|
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) |
Computation of near-surface humidity and snow cover
...
- 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 ERA5Discontinuities 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 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 and 21:00 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 above section, Data organisation and how to download ERA5.
- ERA5: large 10m windsERA5: 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.
- Wind values are far too low on pressure levels at the poles in the Climate Data Store (CDS)Wind values are far too low on pressure levels at the poles in the Climate Data Store (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.
- ERA5 surface photosynthetically available radiation (PAR) is too low, so surface PAR and clear sky surface PAR have not been published. ERA5 is produced by the ECMWF Integrated Forecasting System (IFS), which we suspect has a bug in the calculation of surface PAR in that it looks like it is taken from the wrong parts of the spectrum. We have shortwave bands that include 0.442-0.625 micron, 0.625-0.778 micron and 0.778-1.24 micron. PAR is coded as if it was intending to sum all of the radiation in the first of these and 0.42 of the second (to account for the fact that PAR is normally defined to stop at 0.7 microns. However, 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, but it is not possible to correct previously released data.
Expand title The instantaneous turbulent surface stress components (eastward and northward) and friction velocity tend to be too small ERA5 has output analysis values for the instantaneous surface stress components and friction velocity.
There is however an issue with those analysis values over the oceans.
The analysis for those type of surface parameters is obtained by running the surface module to connect the surface with the model level analysed variables.
However, at that stage, the surface aero-dynamical roughness length scale (z0) over the oceans is not initialised from its actual value but a constant value of 0.0001 is used instead.
This initial value of z0 is needed to determine the initial value of u* and the surface stress based on solving for a simple logarithmic wind profile between the surface and the lowest model wind. This initial u* is in turn used to determine the value of the exchange coefficients needed to determine the output 10m winds (normal and neutral) and u* (see (3.91) to (3.94) with (3.26) in the IFS documentation). The surface stress is output as initialised.
This initial value for z0 is generally too low ( by one order of magnitude or more):
Over the oceans, for winds above few m/s, z0 is modelled using the Charnock relation:
z0 ~ (alpha/g) u*^2
where alpha is the Charnock parameter, g is gravity, and u* is the friction velocity
with typical values of
alpha ~ 0.018
g=9.81
u*^2 = Cd U10^2
where Cd is the drag coefficient
Cd ~ 0.008 + 0.0008 U10
for U10=10m/s => z0 ~ 0.003
As a consequence, the instantaneous surface stress components and friction velocity will tend to be too low
For forecast data, the same problem affects step 0, however, it will not affect the accumulated surface stress parameters (recall the accumulated parameters are produced by running short range forecasts),
because, the accumulation starts from the first time step (i.e. at time step 0 all accumulated variables are initialised to 0.).
Note that this problem can easily be fixed, by using the initial value of Charnock that is available at initial time.
- 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
...
- Wrong values of U/V on pressure levels in the Climate Data Store (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.
Expand title More information and details for downloading ERA5.1 ERA5.1 is a re-run of ERA5 for the years 2000 to 2006 only. ERA5.1 was produced to improve upon the cold bias in the lower stratosphere exhibited by ERA5 during this period. Moreover, ERA5.1 analyses have a better representation of the following features:
- upper stratospheric temperature
- stratospheric humidity
The lower and middle troposphere in ERA5.1 are similar to those in ERA5, as is the synoptic evolution in the extratropical stratosphere.
For access to ERA5.1 data read Data organisation and how to download ERA5. The dataset is 'reanalysis-era5.1-complete' in the CDS API.
If you retrieved ERA5.1 from the CDS 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.
...
- If you have downloaded ERA5 data interactively from the Climate Data Store website or programmatically using the CDS API service (except
'reanalysis-era5-complete'
or'reanalysis-era5.
1
-complete' or '
), then please proceed as follows:reanalysis-era5-complete-preliminary-back-extension'
...
- If you have downloaded ERA5 data from the complete archive, physically stored on the MARS Tape archive system using the CDS-API (
'reanalysis-era5-complete'
or'reanalysis-era5.
1
-complete' or '
) or via authorised access to MARS, then please contact the C3S Helpdesk at ECMWF.reanalysis-era5-complete-preliminary-back-extension'
...