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Parameters available in the ECMWF ERA-40 Re-analysis data held at the BADC


Introduction

The BADC archives a range of parameters produced by the ECMWF ERA-40 Re-analysis project.

The tables on this web page display all the parameters that are available for each grid type and resolution. The tables also include the time period and the type and number of levels for which each parameter is available.

Descriptions of the various grids and level types are also provided.

Details of the available parameters are also listed for the Operational and ERA-15 data sets on separate pages.

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N80 Reduced Gaussian Gridded data

There are 7 types of ERA-40 data archived on the N80 Reduced Gaussian Grid, 5 analysis archives and 2 forecasts archives. The analyses are available on model levels, pressure levels, on surface/single levels, on potential temperature levels and on potential vorticity levels. Forecasts are available on model levels and on surface/single levels. Please see the ECMWF Model Grids page for an explanation of the N80 Reduced Gaussian Grid.

Gaussian Gridded Analyses on Model Levels (ggamYYYYDDHHTTPPP.grb)

Table 1 shows the Model Level parameters available for ERA-40 analysis data on the N80 Reduced Gaussian Grid. These files are located in the directory:

/badc/ecmwf-e40/data/gg/am/

They can also be accessed via the web-interface (by registered BADC users) at:
http://www.badc.rl.ac.uk/cgi-bin/data_browser/data_browser/badc/ecmwf-e40/data/gg/am/

The N80 Reduced Gaussian Gridded model level analyses are stored following the BADC's ERA-40 file-naming convention.

The complete file and directory structure of the N80 Reduced Gaussian Gridded model level data takes the form of:

/badc/ecmwf-e40/data/gg/am/YYYY/MM/DD/ggamYYYYDDHHTTPPP.grb

Table 1.   Parameters, dates and levels available for the ECMWF ERA-40 Re-analysis N80 Reduced Gaussian Gridded model level fields.
Dates Parameters Levels
Start End Parameters (Name) ECMWF code (numeric) ECMWF code Units Levels

Total Levels

See Status pageSee Status pageSpecific humidity133Qkg/kg1-6060
""Ozone mass mixing ratio203O3kg/kg""

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Gaussian Gridded Analyses on Pressure Levels (ggapYYYYDDHHTTPPP.grb)

Table 2 shows the Pressure Level parameters available for ERA-40 analysis data on the N80 Reduced Gaussian Grid. There are also two parameters, u-velocity and v-velocity, that are stored on a N80 Full Gaussian Grid (due to the interpolation from spectral fields). These files are located in the directory:

/badc/ecmwf-e40/data/gg/ap/

They can also be accessed via the web-interface (by registered BADC users) at:
http://www.badc.rl.ac.uk/cgi-bin/data_browser/data_browser/badc/ecmwf-e40/data/gg/ap/

The N80 Reduced Gaussian Gridded pressure level analyses are stored following the BADC's ERA-40 file-naming convention.

The complete file and directory structure of the N80 Reduced Gaussian Gridded pressure level data takes the form of:

/badc/ecmwf-e40/data/gg/ap/YYYY/MM/DD/ggapYYYYDDHHTTPPP.grb

Table 2.   Parameters, dates and levels available for the ECMWF ERA-40 Re-analysis N80 Reduced Gaussian Gridded pressure level fields.
Dates Parameters Levels
Start End Parameters (Name) ECMWF code (numeric) ECMWF code Units Levels

Total Levels

See Status pageSee Status pagePotential vorticity60PVm2 s-1 K kg-11,2,3,5,7,10,20,30,50,70,100,150,200,250,300,400,500,600,700,775,850,925,100023
""U-velocity*131Um2 s-2""
""V-velocity*132Vm2 s-2""
""Specific humidity133Qkg/kg""
""Ozone Mass Mixing Ratio203O3kg/kg""
* u-velocity and v-velocity are held on an N80 Full Gaussian Grid as opposed to a reduced grid. The extraction process requires them to be generated from spectral vorticity and divergence fields and therefore these parameters cannot be obtained on the reduced grid.

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Gaussian Gridded Analyses on Surface/Single Levels (ggasYYYYDDHHTTPPP.grb)

Table 3 shows the Surface/Single Level parameters available for ERA-40 analysis data on the N80 Reduced Gaussian Grid. These files are located in the directory:

/badc/ecmwf-e40/data/gg/as/

They can also be accessed via the web-interface (by registered BADC users) at:
http://www.badc.rl.ac.uk/cgi-bin/data_browser/data_browser/badc/ecmwf-e40/data/gg/as/

The N80 Reduced Gaussian Gridded surface/single level analyses are stored following the BADC's ERA-40 file-naming convention.

The complete file and directory structure of the N80 Reduced Gaussian Gridded surface/single level data takes the form of:

/badc/ecmwf-e40/data/gg/as/YYYY/MM/DD/ggasYYYYDDHHTTPPP.grb

Table 3.   Parameters, dates and levels available for the ECMWF ERA-40 Re-analysis N80 Reduced Gaussian Gridded surface/single level fields.
Dates Parameters Levels
Start End Parameters (Name) ECMWF code (numeric) ECMWF code Units Levels

Total Levels

See Status pageSee Status pageLow vegetation cover27LVC(0-1)11
""High vegetation cover28HVC(0-1)""
""Low vegetation type (table index)29LVTindex""
""High vegetation type (table index)30HVTindex""
""Sea ice fraction (1 = full ice, 0 = no ice)31CI(0, 1)""
""Snow albedo32ASN-""
""Snow density33RSNkg""
""Sea surface temperature34SSTKK""
""Sea ice temperature layer 135ISTL1K""
""Sea ice temperature layer 236ISTL2K""
""Sea ice temperature layer 337ISTL3K""
""Sea ice temperature layer 438ISTL4K""
""Soil moisture level 1 (volumetric)39SWVL1m3/m3""
""Soil moisture level 2 (volumetric)40SWVL2m3/m3""
""Soil moisture level 3 (volumetric)41SWVL3m3/m3""
""Soil moisture level 4 (volumetric)42SWVL4m3/m3""
""Geopotential (at the surface = orography)129Zm2 s-2""
""Total column water136TCWkg/m2""
""Total column water vapour137TCWVkg/m2""
""Soil temperature level 1139STL1K""
""Snow Depth141SDm (of water equivalent)""
""Charnock parameter148CHNK-""
""Mean sea level pressure151MSLPa""
""Standard deviation of subgrid scale orography160SDOR-""
""Anisotropy of subgrid scale orography161ISOR-""
""Angle of subgrid scale orography162ANOR-""
""Slope of subgrid scale orography163SLOR-""
""Total cloud cover164TCC(0-1)""
""10 metre u-wind component16510Um s-1""
""10 metre v-wind component16610Vm s-1""
""2 metre temperature1672TK""
""2 metre dewpoint temperature1682DK""
""Soil temperature level 2170STL2K""
""Land/sea mask172LSM(0, 1)""
""Surface roughness173SRm""
""Albedo174AL-""
""Soil temperature level 3183STL3K""
""Low cloud cover186LCC(0-1)""
""Medium cloud cover187MCC(0-1)""
""High cloud cover188HCC(0-1)""
""Skin reservoir content198SRCm (of water)""
""Total column ozone206TCO3kg m-2""
""Logarithm of surface roughness length for heat234LSRH-""
""Skin temperature235SKTK""
""Soil temperature level 4236STL4K""
""Temperature of snow layer238TSNK""

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Gaussian Gridded Analyses on Potential Temperature Levels (ggatYYYYDDHHTTPPP.grb)

Table 4 shows the Potential Temperature Level parameters available for ERA-40 analysis data on the N80 Reduced Gaussian Grid. These files are located in the directory:

/badc/ecmwf-e40/data/gg/at/

They can also be accessed via the web-interface (by registered BADC users) at:
http://www.badc.rl.ac.uk/cgi-bin/data_browser/data_browser/badc/ecmwf-e40/data/gg/at/

The N80 Reduced Gaussian Gridded potential temperature level analyses are stored following the BADC's ERA-40 file-naming convention.

The complete file and directory structure of the N80 Reduced Gaussian Gridded potential temperature level data takes the form of:

/badc/ecmwf-e40/data/gg/at/YYYY/MM/DD/ggatYYYYDDHHTTPPP.grb

Table 4.   Parameters, dates and levels available for the ECMWF ERA-40 Re-analysis N80 Reduced Gaussian Gridded potential temperature level fields.
Dates Parameters Levels
Start End Parameters (Name) ECMWF code (numeric) ECMWF code Units Levels

Total Levels

See Status pageSee Status pagePotential vorticity60PVm2 s-1 K kg-1265, 275, 285, 300, 315, 330, 350, 370, 395, 430, 475, 530, 600, 700, 85015
""Specific humidity133Qkg/kg""
""Ozone mass mixing ratio203O3kg/kg""

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Gaussian Gridded Analyses on Potential Vorticity Levels (ggavYYYYDDHHTTPPP.grb)

Table 5 shows the Potential Vorticity Level parameters available for ERA-40 analysis data on the N80 Reduced Gaussian Grid. These files are located in the directory:

/badc/ecmwf-e40/data/gg/av/

They can also be accessed via the web-interface (by registered BADC users) at:
http://www.badc.rl.ac.uk/cgi-bin/data_browser/data_browser/badc/ecmwf-e40/data/gg/av/

The N80 Reduced Gaussian Gridded potential vorticity level analyses are stored following the BADC's ERA-40 file-naming convention.

The complete file and directory structure of the N80 Reduced Gaussian Gridded potential vorticity level data takes the form of:

/badc/ecmwf-e40/data/gg/av/YYYY/MM/DD/ggavYYYYDDHHTTPPP.grb

Table 5.   Parameters, dates and levels available for the ECMWF ERA-40 Re-analysis N80 Reduced Gaussian Gridded potential vorticity level fields.
Dates Parameters Levels
Start End Parameters (Name) ECMWF code (numeric) ECMWF code Units Levels

Total Levels

See Status pageSee Status pagePotential temperature3PTK11
""Pressure54PRESPa""
""Geopotential (at the surface = orography)129Zm2 s-2""
""U-velocity131Ums-1""
""V-velocity132Vms-1""
""Specific humidity133Qkg/kg""
""Ozone mass mixing ratio203O3kg/kg""

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Gaussian Gridded Forecasts on Model Levels (ggfmYYYYDDHHTTPPP.grb)

Table 6 shows the Model Level parameters available for ERA-40 forecast data on the N80 Reduced Gaussian Grid. These files are located in the directory:

/badc/ecmwf-e40/data/gg/fm/

They can also be accessed via the web-interface (by registered BADC users) at:
http://www.badc.rl.ac.uk/cgi-bin/data_browser/data_browser/badc/ecmwf-e40/data/gg/fm/

The N80 Reduced Gaussian Gridded potential vorticity level forecasts are stored following the BADC's ERA-40 file-naming convention.

The complete file and directory structure of the N80 Reduced Gaussian Gridded model level data takes the form of:

/badc/ecmwf-e40/data/gg/fm/YYYY/MM/DD/ggfmYYYYDDHHTTPPP.grb

Table 6.   Parameters, dates and levels available for the ECMWF ERA-40 Re-analysis N80 Reduced Gaussian Gridded model level fields.
Dates Parameters Levels
Start End Parameters (Name) ECMWF code (numeric) ECMWF code Units Levels

Total Levels

See Status pageSee Status pageCloud liquid water content246CLWCkg/kg1-6060
""Cloud ice water content247CIWCkg/kg""
""Cloud cover248CC(0-1)""

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Gaussian Gridded Forecasts on Surface/Single Levels (ggfsYYYYDDHHTTPPP.grb)

Table 7 shows the Surface/Single Level parameters available for ERA-40 forecast data on the N80 Reduced Gaussian Grid. These files are located in the directory:

/badc/ecmwf-e40/data/gg/fs/

They can also be accessed via the web-interface (by registered BADC users) at:
http://www.badc.rl.ac.uk/cgi-bin/data_browser/data_browser/badc/ecmwf-e40/data/gg/fs/

The N80 Reduced Gaussian Gridded surface/single level forecasts are stored following the BADC's ERA-40 file-naming convention.

The complete file and directory structure of the N80 Reduced Gaussian Gridded surface/single level data takes the form of:

/badc/ecmwf-e40/data/gg/fsYYYY/MM/DD/ggfsYYYYDDHHTTPPP.grb

Table 7.   Parameters, dates and levels available for the ECMWF ERA-40 Re-analysis N80 Reduced Gaussian Gridded surface/single level fields.
Dates Parameters Levels
Start End Parameters (Name) ECMWF code (numeric) ECMWF code Units Levels

Total Levels

See Status pageSee Status pageSnow evaporation (accum.)44ESm11
""Snow melt (accum.)45SMLTm""
""Wind gusts at 10 m4910FGm s-1""
""Large scale precipitation fraction (accum.)50LSPFs""
""Large scale precipitation (accum.)142LSPm""
""Convective precipitation (accum.)143CPm""
""Snow fall (accum.)144SFm (of water equivalent)""
""Boundary layer dissipation (accum.)145BLDW m-2s""
""Surface sensible heat flux (accum.)146SSHFW m-2s""
""Surface latent heat flux (accum.)147SLHFW m-2s""
""Boundary layer height159BLHm""
""Downward surface solar radiation (accum.)169SSRDW m-2s""
""Downward surface thermal radiation (accum.)175STRDW m-2s""
""Surface solar radiation (accum.)176SSRW m-2s""
""Surface thermal radiation (accum.)177STRW m-2s""
""Top solar radiation (accum.)178TSRW m-2s""
""Top thermal radiation (accum.)179TTRW m-2s""
""East/West surface stress (accum.)180EWSSN m-2s""
""North/South surface stress (accum.)181NSSSN m-2s""
""Evaporation (accum.)182Em (of water)""
""Sunshine duration since last post-processing step189SUNDs""
""Latitudinal component of gravity wave stress (accum.)195LGWSN m-2s""
""Meridional component of gravity wave stress (accum.)196MGWSN m-2s""
""Gravity wave dissipation (accum.)197GWDW m-2s""
""Runoff (accum.)201ROm""
""Minimum temp. at 2m since previous post-processing202MN2TK""
""Ozone mass mixing ratio205O3kg/kg""
""Top solar radiation clear sky (accum.)208TSRCW m-2s""
""Top thermal radiation clear sky (accum.)209TTRCW m-2s""
""Surface solar radiation clear sky (accum.)210SSRCW m-2s""
""Surface thermal radiation clear sky (accum.)211STRCW m-2s""
""Instantaneous X surface stress229IEWSN m-2s""
""Instantaneous Y surface stress230INSSN m-2s""
""Instantaneous surface heat flux231ISHFW/m2""
""Instantaneous surface moisture flux (evaporation)232IEkg m-2s""
""Convective snow fall (accum.)239CSFm (of water equivalent)""
""Large scale snow fall (accum.)240LSFm (of water equivalent)""
""Forecast albedo243FAL-""
""Forecast surface roughness244FSRm""
""Forecast logarithm of surface roughness for heat245FLSR-""

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Spectral T159 data

There are 3 types of ERA-40 data archived at Spectral T159 resolution as analyses. They are held on model levels, pressure levels and on potential temperature levels. Please see the ECMWF Model Grids page for an explanation of the Spectral T159 resolution.

Spectral T159 Analyses on Model Levels (spamYYYYDDHHTTPPP.grb)

Table 8 shows the Model Level parameters available for ERA-40 analysis data at Spectral T159 resolution. These files are located in the directory:

/badc/ecmwf-e40/data/sp/am/

They can also be accessed via the web-interface (by registered BADC users) at:
http://www.badc.rl.ac.uk/cgi-bin/data_browser/data_browser/badc/ecmwf-e40/data/sp/am/

The Spectral T159 model level analyses are stored following the BADC's ERA-40 file-naming convention.

The complete file and directory structure of the N80 Reduced Gaussian Gridded model level data takes the form of:

/badc/ecmwf-e40/data/sp/am/YYYY/MM/DD/spamYYYYDDHHTTPPP.grb

Table 8.   Parameters, dates and levels available for the ECMWF ERA-40 Re-analysis Spectral T159 model level fields.
Dates Parameters Levels
Start End Parameters (Name) ECMWF code (numeric) ECMWF code Units Levels

Total Levels

See Status pageSee Status pageGeopotential (at the surface = orography)129Zm2 s-21-6060
""Temperature130TK""
""U-velocity131Ums-1""
""V-velocity132Vms-1""
""Vertical velocity135WPa s-1""
""Vorticity (relative)138VOs-1""
""Log surface pressure152LNSP-""
""Divergence155Ds-1""

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Spectral T159 Analyses on Pressure Levels (spapYYYYDDHHTTPPP.grb)

Table 9 shows the Pressure Level parameters available for ERA-40 analysis data at Spectral T159 resolution. These files are located in the directory:

/badc/ecmwf-e40/data/sp/ap/

They can also be accessed via the web-interface (by registered BADC users) at:
http://www.badc.rl.ac.uk/cgi-bin/data_browser/data_browser/badc/ecmwf-e40/data/sp/ap/

The Spectral T159 pressure level analyses are stored following the BADC's ERA-40 file-naming convention.

The complete file and directory structure of the N80 Reduced Gaussian Gridded pressure level data takes the form of:

/badc/ecmwf-e40/data/sp/ap/YYYY/MM/DD/spapYYYYDDHHTTPPP.grb

Table 9.   Parameters, dates and levels available for the ECMWF ERA-40 Re-analysis Spectral T159 pressure level fields.
Dates Parameters Levels
Start End Parameters (Name) ECMWF code (numeric) ECMWF code Units Levels

Total Levels

See Status pageSee Status pageGeopotential (at the surface = orography)129Zm2 s-21,2,3,5,7,10,20,30,50,70,100,150,200,250,300,400, 500,600,700,775,850,925,100023
""Temperature130TK""
""U-velocity131Ums-1""
""V-velocity132Vms-1""
""Vertical velocity135WPa s-1""
""Vorticity (relative)138VOs-1""
""Divergence155Ds-1""
""Relative humidity157R%""

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Spectral T159 Analyses on Potential Temperature Levels (spatYYYYDDHHTTPPP.grb)

Table 10 shows the Potential Temperature Level parameters available for ERA-40 analysis data at Spectral T159 resolution. These files are located in the directory:

/badc/ecmwf-e40/data/sp/at/

They can also be accessed via the web-interface (by registered BADC users) at:
http://www.badc.rl.ac.uk/cgi-bin/data_browser/data_browser/badc/ecmwf-e40/data/sp/at/

The Spectral T159 potential temperature level analyses are stored following the BADC's ERA-40 file-naming convention.

The complete file and directory structure of the N80 Reduced Gaussian Gridded potential temperature level data takes the form of:

/badc/ecmwf-e40/data/sp/at/YYYY/MM/DD/spatYYYYDDHHTTPPP.grb

Table 10.   Parameters, dates and levels available for the ECMWF ERA-40 Re-analysis Spectral T159 potential temperature level fields.
Dates Parameters Levels
Start End Parameters (Name) ECMWF code (numeric) ECMWF code Units Levels

Total Levels

See Status pageSee Status pageMontgomery potential53MONTm2 s-21,2,3,5,7,10,20,30,50,70,100,150,200,250,300,400,500,600,700,775,850,925,100023
""Pressure54PRESPa""
""U-velocity131Ums-1""
""V-velocity132Vms-1""
""Vorticity (relative)138VOs-1""
""Divergence155Ds-1""

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Regular Gridded data

Surface/single level ERA-40 data is archived on the 1° x 1° Regular Grid for both analyses and forecasts. Please see the ECMWF Model Grids page for an explanation of the 1° x 1° Regular Grid.

The software and method of interpolation used to convert the data from the N80 Reduced Gaussian grid to a 1° x 1° regular grid is described on the Model Grids page.

1° x 1° Regular Gridded Analyses on Surface/Single Levels (gpasYYYYDDHHTTPPP.grb)

Table 11 shows the Surface/Single Level parameters available for ERA-40 analysis data on the 1° x 1° Regular Grid. These files are located in the directory:

/badc/ecmwf-e40/data/gp/as/

They can also be accessed via the web-interface (by registered BADC users) at:
http://www.badc.rl.ac.uk/cgi-bin/data_browser/data_browser/badc/ecmwf-e40/data/gp/as/

The 1° x 1° Regular Gridded surface/single level analyses are stored following the BADC's ERA-40 file-naming convention.

The complete file and directory structure of the 1° x 1° Regular Gridded surface/single level data takes the form of:

/badc/ecmwf-e40/data/gp/as/YYYY/MM/DD/gpasYYYYDDHHTTPPP.nc

Table 11.   Parameters, dates and levels available for the ECMWF ERA-40 Re-analysis 1° x 1° Regular Gridded surface/single level fields.
Dates Parameters Levels
Start End Parameters (Name) ECMWF code (numeric) ECMWF code Units Levels

Total Levels

See Status pageSee Status pageLow vegetation cover27LVC(0-1)11
""High vegetation cover28HVC(0-1)""
""Low vegetation type (table index)29LVTindex""
""High vegetation type (table index)30HVTindex""
""Snow albedo32ASN-""
""Snow density33RSNkg""
""Sea ice temperature layer 135ISTL1K""
""Sea ice temperature layer 236ISTL2K""
""Sea ice temperature layer 337ISTL3K""
""Sea ice temperature layer 438ISTL4K""
""Soil moisture level 1 (volumetric)39SWVL1m3/m3""
""Soil moisture level 2 (volumetric)40SWVL2m3/m3""
""Soil moisture level 3 (volumetric)41SWVL3m3/m3""
""Soil moisture level 4 (volumetric)42SWVL4m3/m3""
""Geopotential (at the surface = orography)129Zm2 s-2""
""Total column water136TCWkg/m2""
""Total column water vapour137TCWVkg/m2""
""Soil temperature level 1139STL1K""
""Snow Depth141SDm (of water equivalent)""
""Charnock parameter148CHNK-""
""Mean sea level pressure151MSLPa""
""Standard deviation of subgrid scale orography160SDOR-""
""Anisotropy of subgrid scale orography161ISOR-""
""Angle of subgrid scale orography162ANOR-""
""Slope of subgrid scale orography163SLOR-""
""Total cloud cover164TCC(0-1)""
""10 metre u-wind component16510Um s-1""
""10 metre v-wind component16610Vm s-1""
""2 metre temperature1672TK""
""2 metre dewpoint temperature1682DK""
""Soil temperature level 2170STL2K""
""Land/sea mask172LSM(0, 1)""
""Surface roughness173SRm""
""Albedo174AL-""
""Soil temperature level 3183STL3K""
""Low cloud cover186LCC(0-1)""
""Medium cloud cover187MCC(0-1)""
""High cloud cover188HCC(0-1)""
""Skin reservoir content198SRCm (of water)""
""Total column ozone206TCO3kg m-2""
""Logarithm of surface roughness length for heat234LSRH-""
""Skin temperature235SKTK""
""Soil temperature level 4236STL4K""
""Temperature of snow layer238TSNK""

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1° x 1° Regular Gridded Forecasts on Surface/Single Levels (gpfsYYYYDDHHTTPPP.grb)

Table 12 shows the Surface/Single Level parameters available for ERA-40 forecast data on the 1° x 1° Regular Grid. These files are located in the directory:

/badc/ecmwf-e40/data/gp/fs/

They can also be accessed via the web-interface (by registered BADC users) at:
http://www.badc.rl.ac.uk/cgi-bin/data_browser/data_browser/badc/ecmwf-e40/data/gp/fs/

The 1° x 1° Regular Gridded surface/single level forecasts are stored following the BADC's ERA-40 file-naming convention.

The complete file and directory structure of the 1° x 1° Regular Gridded surface/single level data takes the form of:

/badc/ecmwf-e40/data/gp/fsYYYY/MM/DD/gpfsYYYYDDHHTTPPP.nc

Table 12.   Parameters, dates and levels available for the ECMWF ERA-40 Re-analysis 1° x 1° Regular Gridded surface/single level fields.
Dates Parameters Levels
Start End Parameters (Name) ECMWF code (numeric) ECMWF code Units Levels

Total Levels

See Status pageSee Status pageSnow evaporation (accum.)44ESm11
""Snow melt (accum.)45SMLTm""
""Wind gusts at 10 m4910FGm s-1""
""Large scale precipitation fraction (accum.)50LSPFs""
""Large scale precipitation (accum.)142LSPm""
""Convective precipitation (accum.)143CPm""
""Snow fall (accum.)144SFm (of water equivalent)""
""Boundary layer dissipation (accum.)145BLDW m-2s""
""Surface sensible heat flux (accum.)146SSHFW m-2s""
""Surface latent heat flux (accum.)147SLHFW m-2s""
""Boundary layer height159BLHm""
""Downward surface solar radiation (accum.)169SSRDW m-2s""
""Downward surface thermal radiation (accum.)175STRDW m-2s""
""Surface solar radiation (accum.)176SSRW m-2s""
""Surface thermal radiation (accum.)177STRW m-2s""
""Top solar radiation (accum.)178TSRW m-2s""
""Top thermal radiation (accum.)179TTRW m-2s""
""East/West surface stress (accum.)180EWSSN m-2s""
""North/South surface stress (accum.)181NSSSN m-2s""
""Evaporation (accum.)182Em (of water)""
""Sunshine duration since last post-processing step189SUNDs""
""Latitudinal component of gravity wave stress (accum.)195LGWSN m-2s""
""Meridional component of gravity wave stress (accum.)196MGWSN m-2s""
""Gravity wave dissipation (accum.)197GWDW m-2s""
""Runoff (accum.)201ROm""
""Minimum temp. at 2m since previous post-processing202MN2TK""
""Ozone mass mixing ratio205O3kg/kg""
""Top solar radiation clear sky (accum.)208TSRCW m-2s""
""Top thermal radiation clear sky (accum.)209TTRCW m-2s""
""Surface solar radiation clear sky (accum.)210SSRCW m-2s""
""Surface thermal radiation clear sky (accum.)211STRCW m-2s""
""Instantaneous X surface stress229IEWSN m-2s""
""Instantaneous Y surface stress230INSSN m-2s""
""Instantaneous surface heat flux231ISHFW/m2""
""Instantaneous surface moisture flux (evaporation)232IEkg m-2s""
""Convective snow fall (accum.)239CSFm (of water equivalent)""
""Large scale snow fall (accum.)240LSFm (of water equivalent)""
""Forecast albedo243FAL-""
""Forecast surface roughness244FSRm""
""Forecast logarithm of surface roughness for heat245FLSR-""

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An explanation of the forecast files

The BADC archives ERA-40 data as both analyses and forecasts. Analyses represent the state of the atmosphere at the zero time-step, i.e. the start of a forecast. This is the point at which initial observations have been assimilated with the 6-hour forecast of the previous model run. Many parameters are available in the analyses and are archived only at the zero time-step (i.e. a file for 15 January 1991 at midday would include "1991011512" in its name and would represent the state of the atmosphere at midday on that day). The analyses are calculated and archived 4 times a day, at 00hr, 06hr, 12hr and 18hrs.

Forecast files contain parameters that are not available in the analyses. Such parameters are accumulated from the analysis time to the time of the forecast. In order to make the forecasts compatible with the analysis fields of the same time-step we archive the 24-hour forecasts starting at midnight for ERA-40. This means that the forecasts files any particular day will be accumulated throughout the 24-hours of that day. For example, a forecast file for 25 February 1992 would include "1992022500" in its name and would represent accumulated fields for the entire 24-hour period of that day. Hence, there is only 1 forecast file per day. Note that the ECMWF actually provides all the analysis fields at forecast times as well, this data is not archived at the BADC.

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