- Created by Glenn Carver, last modified on Apr 02, 2021
Introduction
This page describes the files typically found in an OpenIFS 43r3 experiment. Experiment files are provided by the OpenIFS team at ECMWF as gzipped tarfile. These files provide initial and boundary conditions and currently are provided on request to the user for download via ftp.ecmwf.int.
In order to request initial data for an experiment please email openifs-support@ecmwf.int
Note that the experiment ID forms part of the name for all binary ICM* GRIB files. The experiment ID is also stored inside each GRIB file. Grib tools can be used to modify the experiment ID if required. Users should not just copy the files to a new name.
Overview of an Initial File Archive
The table below shows an initial data provided in order to run OpenIFS for a 48 hour forecast with experiment ID h9wu, starting on 1990-01-01 at 00 UTC using a Tco159 cubic octahedral grid with 91 vertical model levels.
The files will be provided by OpenIFS at ECMWF as a gzipped tar archive, which can be uncompressed and unpacked using:
% tar xvzf h9wu_19900101.tgz
If your version of the 'tar' command does not support the 'z' uncompress option, do it in two stages using the 'gunzip' command first and then 'tar xvf' on the resulting file.
The directory structure consists of a top-level directory named after the experiment ID, which differs for each experiment (h9wu in the example below), and subdirectories for all available start dates (here only one start date, 1990010100). The subdirectory ecmwf contains namelist files and several pre-run log file outputs to compare your experiment against.
| Path h9wu is an example | File name | Format | Typical Size (Tco159) | Content | |
|---|---|---|---|---|---|
h9wu/1990010100/ | ICMCLh9wuINIT | GRIB-1 | 14 MB | Input file with initial and boundary conditions (for the first 7 days from the start date). This file contains surface and soil information (sea ice area fraction, SSTs, albedo, soil temperature etc.) | ci, stl1, al, aluvp, aluvd, alnip, alnid, lai_lv, lai_hv |
h9wu/1990010100/ | ICMGGh9wuINIT | GRIB-1 | 11 MB | Input file with gridpoint surface initial data (at start date) |
|
h9wu/1990010100/ | ICMGGh9wuINIUA | GRIB-2 | 85 MB | Input file with initial data for the prognostic variables in gridpoint representation on all 91 model levels (at start date) | q, o3, crwc, cswc, clwc, ciwc, cc |
h9wu/1990010100/ | ICMSHh9wuINIT | GRIB-2 | 14 MB | Input file with initial data for the prognostic variables in spectral representation on all 91 model levels (at start date) | lnsp, vo, d, t, z |
h9wu/1990010100/ | cdwavein | GRIB-1 | 64 KB | Input file for the wave model. Initial value of the drag coefficient (at start date) | cdww |
h9wu/1990010100/ | sfcwindin | GRIB-1 | 2.3 MB | Input file for the wave model. Initial value of 10-meter horizontal wind components and sea ice fraction (at start date) | 10u, 10v, ci |
h9wu/1990010100/ | specwavein | GRIB-1 | 16 MB | Input file for the wave model. Initial wave spectra | 2dfd |
h9wu/1990010100/ | uwavein | GRIB-1 | 64 KB | Input file for the wave model. Initial value of wind speed | wind |
h9wu/1990010100/ | wam_grid_tables | Binary | 98 MB | Input file for the wave model. Model grid and tables: other than the IFS model, which obtains the atmospheric grid specifications from the initial data values, the wave model uses this external file to specify its grid parameters | |
h9wu/1990010100/ | wam_subgrid_[0-2] | Binary | 30 MB | Input file for the wave model. Information for model advection, including sub-grid parameterization: pre-computed impact of subgrid bathymetry on wave propagation | |
h9wu/1990010100/ecmwf/ | NODE.001_01.model.1 | Text | 1.6 MB | Output file, this is the main log file of OpenIFS run for a short run of this model experiment, provided for comparison and debugging (may not be provided with each tar archive). | |
h9wu/1990010100/ecmwf/ | ifs.stat.model.1 | Text | 24 KB | Output file, this file provides run time statistics for the model time steps from a pre-calculated model experiment. Useful for debugging (may not be provided with each tar archive). | |
h9wu/1990010100/ecmwf/ | namelistfc | Text | 5 KB | Namelist file with detailed experiment set up. This file serves as a reference namelist and should remain in this directory. | |
h9wu/1990010100/ecmwf/ | fort.4 | Text | 5 KB | This is a copy of namelistfc and should be moved to the start date directory. The model will expect to find fort.4 in its experiment directory, together with the other initial data files. fort.4 should be customised for the model experiment. | |
h9wu/1990010100/ecmwf/ | wam_namelist | Text | 4 KB | Namelist file for the wave model |
CY40R1
Note that in OpenIFS 40r1 the ICMGG****INIT file contained fewer variables as the Lake model was not part of 40r1. Also, ICMSH****INIT contains both GRIB level 1 and level 2 messages.
Contents of the Initial Data Files
In the following sections the content of the individual GRIB initial files is further explained. Click on the parameters in the table in order to link to the ECMWF GRIB parameter database for a more comprehensive description of the variables.
ICMCL****INIT
This file provides surface boundary conditions for the duration of the experiment. The data in this file is interpolated from climatological monthly means to daily values at 12:00 UTC over the duration of the forecast experiment (FCLENGTH).
Origin of the climatological data (climate.v015 for OpenIFS 43r3) and further details are in the IFS documentation, Part IV (Physical Processes) Chapter 11. The data sets that are used for the climatology are described in Section 11.2.
During the preparation process of initial data packages climatological SSTs (which originate from ERA-40) are replaced with daily values from more recent meteorological reanalyses, e.g. such as ERA5.
| Parameter | Grib code | Description |
|---|---|---|
ci | 31 | Sea ice area fraction |
stl1 | 139 | Soil temperature level 1 (includes sea surface temperatures) |
al | 174 | Albedo |
aluvp | 15 | UV visible albedo for direct radiation |
aluvd | 16 | UV visible albedo for diffuse radiation |
alnip | 17 | Near IR albedo for direct radiation |
alnid | 18 | Near IR albedo for diffuse radiation |
lai_lv | 66 | Leaf area index, low vegetation |
lai_hv | 67 | Leaf area index, high vegetation |
ICMGG****INIT
The data in this file contains the initial conditions at the start of the experiment.
Parameters that are not available from requested analyses type (e.g. ERA5) will be substituted from the climatological files described above.
| Parameter | Grib code | Description | Parameter | Grib code | Description | |
|---|---|---|---|---|---|---|
stl1 | 139 | Soil temperature level 1 | chnk | 148 | Charnock parameter | |
stl2 | 170 | Soil temperature level 2 | lsm | 172 | Land-sea mask | |
stl3 | 183 | Soil temperature level 3 | sr | 173 | Surface roughness | |
stl4 | 236 | Soil temperature level 4 | al | 174 | Albedo | |
swvl1 | 39 | Volumetric soil water layer 1 | aluvp | 15 | UV visible albedo for direct radiation | |
swvl2 | 40 | Volumetric soil water layer 2 | aluvd | 16 | UV visible albedo for diffuse radiation | |
swvl3 | 41 | Volumetric soil water layer 3 | alnip | 17 | Near IR albedo for direct radiation | |
swvl4 | 42 | Volumetric soil water layer 4 | alnid | 18 | Near IR albedo for diffuse radiation | |
sd | 141 | Snow depth | lai_lv | 66 | Leaf area index, low vegetation | |
src | 198 | Skin reservoir content | lai_hv | 67 | Leaf area index, high vegetation | |
skt | 235 | Skin temperature | sdfor | 74 | Standard deviation of filtered subgrid orography | |
ci | 31 | Sea ice area fraction | slt | 43 | Soil type | |
lmlt | 228008 | Lake mix-layer temperature | sdor | 160 | Standard deviation of orography | |
lmld | 228009 | Lake mix-layer depth | isor | 161 | Anisotropy of sub-gridscale orography | |
lblt | 228010 | Lake bottom temperature | anor | 162 | Angle of sub-gridscale orography | |
ltlt | 228011 | Lake total layer temperature | slor | 163 | Slope of sub-gridscale orography | |
lshf | 228012 | Lake shape factor | lsrh | 234 | Logarithm of surface roughness length for heat | |
lict | 228013 | Lake ice temperature | cvh | 28 | High vegetation cover | |
licd | 228014 | Lake ice depth | cvl | 27 | Low vegetation cover | |
tsn | 238 | Temperature of snow layer | tvh | 30 | Type of high vegetation | |
asn | 32 | Snow albedo | tvl | 29 | Type of low vegetation | |
rsn | 33 | Snow density | cl | 26 | Lake cover | |
sst | 34 | Sea surface temperature | dl | 228007 | Lake depth | |
istl1 | 35 | Ice temperature layer 1 | ||||
istl2 | 36 | Ice temperature layer 2 | ||||
istl3 | 37 | Ice temperature layer 3 | ||||
istl4 | 38 | Ice temperature layer 4 |
ICMGG****INIUA
This file contains "upper atmosphere" initial data, see the above section for the origin of the data.
| Parameter | Grib code | Description |
|---|---|---|
q | 133 | Specific humidity |
o3 | 203 | Ozone mass mixing ratio |
crwc | 75 | Specific rain water content |
cswc | 76 | Specific snow water content |
clwc | 246 | Specific cloud liquid water content |
ciwc | 247 | Specific cloud ice water content |
cc | 248 | Fraction of cloud cover |
ICMSH****INIT
This file contains initial data in spectral formulation, see the above section for the origin of the data.
| Parameter | Grib code | Description |
|---|---|---|
lnsp | 152 | Logarithm of surface pressure |
vo | 138 | Vorticity (relative) |
d | 155 | Divergence |
t | 130 | Temperature |
z | 129 | Geopotential |
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