AABCYYYYMMDDTTP[PPPP][_SSh].EXT
AA is the grid type.
B denotes whether the file contains analysis or forecast data.
C is the level type.
YYYY is the year (e.g. 1994).
MM is the month (from 01 to 12).
DD is the day of the month (from 01 to 31).
TT is the time of day (either 00, 06, 12 or 18).
P[PPPP] is the parameter name (from one to five characters).
[_SSh] is the forecast time step (SS is number of hours since analysis). This field is only included for forecast fields where B is 'f'. 'h' represents the unit hours.
.EXT is the file extension, denoting the file format. The main
archive is stored in GRIB format (.grb) although some data will be available
in NetCDF format (.nc).
Table 1 shows the codes for each grid, field and level type.
Table 1. Grid, field and level types in the
ERA-40 file names.
| Grid type | Field type | Level type | |||
| gg | N80 Reduced Gaussian Grid | a | Analysis (at the zero time-step) | m | Model level data |
| sp | Spectral T159 Resolution | - | - | s | Surface or single level data |
| gp | Regular 1.0° x 1.0° Grid | f | Forecast | p | Pressure level data |
| li | Regular 2.5° x 2.5° Grid | - | - | t | Potential temperature level data |
| lf | Regular 1.125° x 1.125° Grid | - | - | v | Potential vorticity level data |
Parameter abbreviations are used in the file names. These vary in length from one to five characters. Table 2 shows a complete list of the ERA-40 parameter names, abbreviations, numeric ECMWF codes and units.
Table 2. Parameters details in the
ERA-40 file names.
| Parameter name | Parameter code (abbreviation) | ECMWF code (numeric) | Units |
| Potential temperature | PT | 3 | K |
| Low vegetation cover | LVC | 27 | (0-1) |
| High vegetation cover | HVC | 28 | (0-1) |
| Low vegetation type (table index) | LVT | 29 | index |
| High vegetation type (table index) | HVT | 30 | index |
| Sea ice fraction (1 = full ice, 0 = no ice) | CI | 31 | (0, 1) |
| Snow albedo | ASN | 32 | - |
| Snow density | RSN | 33 | kg |
| Sea surface temperature | SSTK | 34 | K |
| Sea ice temperature layer 1 | ISTL1 | 35 | K |
| Sea ice temperature layer 2 | ISTL2 | 36 | K |
| Sea ice temperature layer 3 | ISTL3 | 37 | K |
| Sea ice temperature layer 4 | ISTL4 | 38 | K |
| Soil moisture level 1 (volumetric) | SWVL1 | 39 | m3/m3 |
| Soil moisture level 2 (volumetric) | SWVL2 | 40 | m3/m3 |
| Soil moisture level 3 (volumetric) | SWVL3 | 41 | m3/m3 |
| Soil moisture level 4 (volumetric) | SWVL4 | 42 | m3/m3 |
| Snow evaporation (accum.) | ES | 44 | m |
| Snow melt (accum.) | SMLT | 45 | m |
| Wind gusts at 10 m | 10FG | 49 | m s-1 |
| Large scale precipitation fraction (accum.) | LSPF | 50 | s |
| Montgomery potential | MONT | 53 | m2 s-2 |
| Pressure | PRES | 54 | Pa |
| Potential vorticity | PV | 60 | m2 s-1 K kg-1 |
| Geopotential (at the surface = orography) | Z | 129 | m2 s-2 |
| Temperature | T | 130 | K |
| U-velocity | U | 131 | ms-1 |
| V-velocity | V | 132 | ms-1 |
| Specific humidity | Q | 133 | kg/kg |
| Vertical velocity | W | 135 | Pa s-1 |
| Total column water | TCW | 136 | kg/m2 |
| Total column water vapour | TCWV | 137 | kg/m2 |
| Vorticity (relative) | VO | 138 | s-1 |
| Soil temperature level 1 | STL1 | 139 | K |
| Snow Depth | SD | 141 | m (of water equivalent) |
| Large scale precipitation (accum.) | LSP | 142 | m |
| Convective precipitation (accum.) | CP | 143 | m |
| Snow fall (accum.) | SF | 144 | m (of water equivalent) |
| Boundary layer dissipation (accum.) | BLD | 145 | W m-2s |
| Surface sensible heat flux (accum.) | SSHF | 146 | W m-2s |
| Surface latent heat flux (accum.) | SLHF | 147 | W m-2s |
| Charnock parameter | CHNK | 148 | - |
| Mean sea level pressure | MSL | 151 | Pa |
| Log surface pressure | LNSP | 152 | - |
| Divergence | D | 155 | s-1 |
| Relative humidity | R | 157 | % |
| Boundary layer height | BLH | 159 | m |
| Standard deviation of subgrid scale orography | SDOR | 160 | - |
| Anisotropy of subgrid scale orography | ISOR | 161 | - |
| Angle of subgrid scale orography | ANOR | 162 | - |
| Slope of subgrid scale orography | SLOR | 163 | - |
| Total cloud cover | TCC | 164 | (0-1) |
| 10 metre u-wind component | 10U | 165 | m s-1 |
| 10 metre v-wind component | 10V | 166 | m s-1 |
| 2 metre temperature | 2T | 167 | K |
| 2 metre dewpoint temperature | 2D | 168 | K |
| Downward surface solar radiation (accum.) | SSRD | 169 | W m-2s |
| Soil temperature level 2 | STL2 | 170 | K |
| Land/sea mask | LSM | 172 | (0, 1) |
| Surface roughness | SR | 173 | m |
| Albedo | AL | 174 | - |
| Downward surface thermal radiation (accum.) | STRD | 175 | W m-2s |
| Surface solar radiation (accum.) | SSR | 176 | W m-2s |
| Surface thermal radiation (accum.) | STR | 177 | W m-2s |
| Top solar radiation (accum.) | TSR | 178 | W m-2s |
| Top thermal radiation (accum.) | TTR | 179 | W m-2s |
| East/West surface stress (accum.) | EWSS | 180 | N m-2s |
| North/South surface stress (accum.) | NSSS | 181 | N m-2s |
| Evaporation (accum.) | E | 182 | m (of water) |
| Soil temperature level 3 | STL3 | 183 | K |
| Low cloud cover | LCC | 186 | (0-1) |
| Medium cloud cover | MCC | 187 | (0-1) |
| High cloud cover | HCC | 188 | (0-1) |
| Sunshine duration since last post-processing step | SUND | 189 | s |
| Latitudinal component of gravity wave stress (accum.) | LGWS | 195 | N m-2s |
| Meridional component of gravity wave stress (accum.) | MGWS | 196 | N m-2s |
| Gravity wave dissipation (accum.) | GWD | 197 | W m-2s |
| Skin reservoir content | SRC | 198 | m (of water) |
| Maximum temp. at 2m since previous post-processing | MX2T | 201 | K |
| Minimum temp. at 2m since previous post-processing | MN2T | 202 | K |
| Ozone mass mixing ratio | O3 | 203 | kg/kg |
| Runoff (accum.) | RO | 205 | m |
| Total column ozone | TCO3 | 206 | kg m-2 |
| Top solar radiation clear sky (accum.) | TSRC | 208 | W m-2s |
| Top thermal radiation clear sky (accum.) | TTRC | 209 | W m-2s |
| Surface solar radiation clear sky (accum.) | SSRC | 210 | W m-2s |
| Surface thermal radiation clear sky (accum.) | STRC | 211 | W m-2s |
| Instantaneous X surface stress | IEWS | 229 | N m-2s |
| Instantaneous Y surface stress | INSS | 230 | N m-2s |
| Instantaneous surface heat flux | ISHF | 231 | W/m2 |
| Instantaneous surface moistrue flux (evaporation) | IE | 232 | kg m-2s |
| Logarithm of surface roughness length for heat | LSRH | 234 | - |
| Skin temperature | SKT | 235 | K |
| Soil temperature level 4 | STL4 | 236 | K |
| Temperature of snow layer | TSN | 238 | K |
| Convective snow fall (accum.) | CSF | 239 | m (of water equivalent) |
| Large scale snow fall (accum.) | LSF | 240 | m (of water equivalent) |
| Forecast albedo | FAL | 243 | - |
| Forecast surface roughness | FSR | 244 | m |
| Forecast logarithm of surface roughness for heat | FLSR | 245 | - |
| Cloud liquid water content | CLWC | 246 | kg/kg |
| Cloud ice water content | CIWC | 247 | kg/kg |
| Cloud cover | CC | 248 | (0-1) |
ggap1992010618o3.grb - N80 Reduced Gaussian Grid, Analysis, Pressure Levels, 6 January 1992, 18:00 hours, Ozone Mass Mixing Ratio field, GRIB format.
spat1962102712vo.grb - T159 Spectral resolution, Analysis, Potential Temperature Levels, 27 October 1962, 12:00 hours, Vorticity (relative), GRIB format.
ggfm1974123100ciwc_24h.grb - N80 Reduced Gaussian Grid, Forecast, Model Levels, 31 December 1974, 00:00 hours (start time of forecast), 24 hours (forecast step time), therefore valid time of data is 1974-12-31 00:00 + 24 hours = 1975-01-01 00:00, Cloud Ice Water Content field, GRIB format.
/badc/ecmwf-e40/data/AA/BC/YYYY/MM/DD/file_name
AA is the grid type.
B denotes whether the file contains analysis or forecast data.
C is the level type.
YYYY is the year (e.g. 1994).
MM is the month (from 01 to 12).
DD is the day of the month (from 01 to 31).
file_name is the file name as discussed above
(e.g. spat1991041700pres.grb).
Note that if you accessing the data via the BADC web-interface (BADC registered users only), the data can be found at:
http://badc.nerc.ac.uk/cgi-bin/data_browser/data_browser/badc/ecmwf-e40/data/
The directory system beyond the
AA/BC/YYYY/MM/DD/file_name