This article show different approaches to convert GRIB to netCDF for use in other analysis and visualisation software. It also describes different methods to interpolate the reduced Gaussian grid to regular grids.
GRIB files are the file format used at ECMWF. GRIB is a WMO standard and consists of GRIB Edition 1 and Edition 2.
The OpenIFS/IFS models output in GRIB format. These files are a mix of GRIB-1 & GRIB-2 messages, the multi-level fields are encoded as GRIB-2, whereas surface fields are GRIB-1. GRIB files can also contain multiple vertical coordinates: pressure levels, model levels, sub-surface levels etc. This can cause a problem with some 3rd party tools, as the same GRIB variable code is used for each axis. The instructions below show how to work around this by splitting the file to separate fields on different vertical axes.
OpenIFS model output
The OpenIFS model outputs two types of files: those beginning with ICMSH contain fields represented as spherical harmonics, those that begin ICMGG contain gridpoint fields. The ICMSH files are the spherical harmonics of the wind fields, pressure and temperature and require a spectral transform to convert to gridded data. Also see controlling the OpenIFS output for more details of output fields and options.
Retrieving data from MARS archive
Please note that if using the MARS archive (apps.ecmwf.int) (e.g. for reanalysis products such as ERA-Interim/ERA-5), it is possible to download the files in netCDF format as well as GRIB.
grib_to_netcdf
This command will convert one or more GRIB files to netCDF and is available with the ECMWF ecCodes software. For more details please see:grib_to_netcdf description.
grib_to_netcdf only works correctly when a single level coordinate is present in the GRIB file. Often the model output files have fields on multiple level types (ie. hybrid model levels and pressure levels).
How to split GRIB file into separate level types
grib_copy ICMGGftkm+001440 ICMGG_[typeOfLevel].grb
In this example, the GRIB model output file ICMGGftkm+001440 contains a number of different model level types. The special square bracket "[ ]" syntax is recognised by grib_copy (and other grib commands such as grib_filter) and can contain any valid GRIB key.
This example will copy the original file, separating the level types into their own file: ICMGG_hybrid.grb, ICMGG_isobaricInhPA.grb, ICMGG_surface ...and so on.
grib_to_netcdf can then be used on the individual files:
Convert GRIB file to netCDF
grib_to_netcdf ICMGG_hybrid.grb -o ICMGG_hybrid.nc
By default, grib_to_netcdf will pack the data into scaled integers with an offset to optimize space.
If you prefer data stored as floats then use:
Convert GRIB to netCDF storing values as floats rather than scaled integers...
grib_to_netcdf -D NC_FLOAT ICMGG_hybrid.grb -o ICMGG_hybrid.nc
To convert from vorticity and divergence to wind u and v, please see CDO instructions below.
Note that grib_to_netcdf does not do any regridding. If the fields use a reduced Gaussian latitude grid, they will not be converted to a regular grid. Use CDO instead to do this as described below.
On this page
The Metview application is available for analysis and visualisation of OpenIFS output and will both convert spectral to gridded parameters and plot reduced Gaussian grid directly.
Please see 'Using Metview with OpenIFS' for more details.
See also...
ecCodes - grib tools
MARS user documentation
EMOSLIB interpolation library
NCL provides a tool to convert both GRIB-1 & GRIB-2 to netCDF called ncl_convert2nc.
NCL example scripts to convert to netCDF are also available.
These instructions assume the use of a recent version of Climate Data Operators (CDO) (available from Max-Planck-Institut, Germany).
CDO supports GRIB-2 but needs either the ecCodes library from ECMWF to be included. This is necessary in order to work correctly with OpenIFS model output.
Check CDO is compiled with grib-api (or ecCodes)
cdo --versionClimate Data Operators version 1.9.6 (http://mpimet.mpg.de/cdo)...........Libraries: HDF5/1.10.4 proj/5.2 xml2/2.9.4Filetypes: srv ext ieg grb1 grb2 nc1 nc2 nc4 nc4c nc5 CDI library version : 1.9.6 cgribex library version : 1.9.2 ecCodes library version : 2.12.5 NetCDF library version : 4.6.2 of Feb 14 2019 10:13:27 $ hdf5 library version : 1.10.4 threadsafe exse library version : 1.4.1 FILE library version : 1.8.3.........
If you find the CDO commands below do not work, you can either build CDO yourself, making sure a recent version of ecCodes is used, or you can use the workaround below.
Interpolate from reduced to regular grid
CDO can be used to interpolate from the reduced Gaussian grid to a regular Gaussian grid:
Convert to regular grid: GRIB-1 only
cdo -R copy <input grib> <output grib>
The -R option only works for GRIB edition 1 (GRIB 1) data as it uses the CGRIBEX decoder.
For GRIB-2 messages it's better to use the setgridtype operator:
Convert to regular grid: GRIB-2
cdo setgridtype,regular <input grib> <output grib>cdo -f nc setgridtype,regular <input grib> <output netcdf>
If you have files with a mix of GRIB-1 and GRIB-2, then either split the file first or compile cdo with "--disable-cgribex --with-eccodes=yes"
If variable names are lost, add the "-t ecmwf" option.
If these steps do not work, see workarounds below.
Steps to convert GRIB to netCDF
Split z axis
Before converting to netCDF, separate the different vertical axes using the generic command: cdo splitzaxis <input file> <output file pattern>.
This will ensure the following steps work correctly:
Example: Separate multiple z axes into individual files
cdo splitzaxis ICMSHg4a4+000000.grb ICMSHg4a4+000000_splitls ICMSH*split*ICMSHg4a4+000000_split01.grbICMSHg4a4+000000_split02.grbICMSHg4a4+000000_split03.grbICMSHg4a4+000000_split04.grb
In this example, the different files might contain: '01' - fields on pressure levels, '02' - fields on model levels, '03' - hybrid levels, '04' - surface and so on. The number of files created depends on the number of different types of levels. Use the command grib_ls to inspect the contents of each split file.
Note that the filename ICMSH in this example, indicates it contains spectral and not gridpoint fields.
Another way to split the file would be using the grib_copy command from the ecCodes software as shown above:
grib_copy ICMSHg4a4+000000.grb ICMSHg4a4+000000_[typeOfLevel].grb
In this case 'typeOfLevel' is a GRIB key. The square brackets is a special syntax to the grib_copy command. This approach works with any GRIB key.
Convert spectral to gridpoint
CDO supports two options for converting spectral to gridpoint data:
- sp2gpl - converts spectral to a linear Gaussian grid, appropriate for IFS data.
- sp2gp - converts spectral to a quadratic Gaussian grid (only use this for T21/42 resolutions)
Both produce a regular Gaussian grid with equal number of longitudes on each latitude row. Remember that a Gaussian grid has irregularly spaced latitudes (but nearly regular). For more details please see the description of these operators on the CDO homepage.
cdo -f nc -sp2gpl <input spectral coefficent grib> <output gridded netcdf>
Convert the resulting output files to netcdf
After any operation converting a GRIB file to any other GRIB file, the conversion to netCDF is just:
Convert GRIB file to netCDF file
cdo -f nc copy <input grib> <output netcdf>
Convert vorticity and divergence to wind
To convert wind components u & v instead of vorticity and divergence, use:
Convert vorticity & divergence to u & v
cdo dv2uvl <input file> <output file>
Interpolate to pressure from model levels
To interpolate to pressure levels from model levels, use:
Interpolate model levels to pressure levels
cdo ml2pl,92500,85000,50000,20000 <input file> <output file>
Viewing contents of GRIB files
There are various commands for inspecting the contents of a GRIB file. The ecCodes software installation required for OpenIFS has useful commands like grib_ls and grib_dump.
Example grib-api command for inspecting a file
grib_ls ICMSHfrq2+000000.grbgrib_dump ICMSHfrq2+000000.grb
Here is another example using the cdo command:
Example cdo command for inspecting GRIB file
$ cdo sinfo ICMSHfrq2+000000.grb File format: GRIB -1 : Institut Source Param Time Typ Grid Size Num Levels Num 1 : ECMWF unknown 11.3 var P16 65792 1 60 1 2 : ECMWF unknown 39.3 var P16 65792 1 60 1 3 : ECMWF unknown 43.3 var P16 65792 1 60 1 4 : ECMWF unknown 44.3 var P16 65792 1 60 1 5 : ECMWF unknown 152.128 var P16 65792 1 1 2 6 : ECMWF unknown 6.3 var P16 65792 1 1 2 Horizontal grids : 1 : spectral > size : dim = 65792 truncation = 255 spc = 32896 complexPacking = 1 Vertical grids : 1 : hybrid level : 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 2 : hybrid level : 1 Time axis : 1 step RefTime = 1999-12-24 12:00:00 Units = hours Calendar = PROLEPTIC YYYY-MM-DD hh:mm:ss YYYY-MM-DD hh:mm:ss YYYY-MM-DD hh:mm:ss YYYY-MM-DD hh:mm:ss 1999-12-24 12:00:00cdo sinfo: Processed 6 variables over 1 timestep. ( 0.04s )
Converting a single file
In this example a single GRIB file with model level data, on a regular Gaussian grid is converted to netCDF with vorticity & divergence replaced by u & v and model level data interpolated to pressure levels.
cdo -f nc copy file.grb file.nccdo dv2uvl file.nc file_uv.nccdo sp2gpl file_uv.nc file_uv_gg.nccdo ml2pl,92500,85000,50000,20000 file_uv_gg.nc file_uv_gg_pl.nc
Converting series of files
The following script shows how to loop over several output files using the steps above to convert to netCDF. Note the spectral parameter files are also converted but the extra command using the sp2gpl operator is first used to convert the variables from spectral to gridpoint on a regular, linear, Gaussian grid.
In this example, we use the pipelining feature of CDO to do both the 'copy' and 'sp2gpl' steps in one command, keeping the entire operations in memory for efficiency.
Sample script to convert OpenIFS GRIB output to netCDF
for i in 000 024 048 072docdo -R copy ICMGGfpp4+000${i}.grb ICMGGfpp4+000${i}_R.grbcdo splitzaxis ICMGGfpp4+000${i}_R.grb ICMGGfpp4+000${i}cdo -f nc copy ICMGGfpp4+000${i}01.grb ICMGGfpp4+000${i}_PL_GP.nc# pressure level gridpoint fieldscdo -f nc copy ICMGGfpp4+000${i}02.grb ICMGGfpp4+000${i}_ML_GP.nc # model level gridpoint fieldscdo splitzaxis ICMSHfpp4+000${i}.grb ICMSHfpp4+000${i}cdo -f nc copy -sp2gpl ICMSHfpp4+000${i}01.grb ICMSHfpp4+000${i}01_PL_GP.grb# spectral fields on press levels transformed to gridpointcdo -f nc copy -sp2gpl ICMSHfpp4+000${i}03.grb ICMSHfpp4+000${i}03_ML_GP.grb# spectral fields on model levels transformed to gridpointcdo -f nc copy -sp2gpl ICMSHfpp4+000${i}04.grb ICMSHfpp4+000${i}04_surf_GP.grb# spectral fields on surface levels transformed to gridpointdonecdo commands can be combined into a single command for greater efficiency.
Using EMOSLIB to interpolate to regular grid
The ECMWF interpolation software library EMOSLIB also provides the capability to interpolate spectral data to regular gaussian grids or regular lat-lon grids, and interpolate regular gaussian grids to regular lat-lon grids.
The EMOSLIB library provides a Fortran library to enable users to write their own interpolation software. Please see the EMOSLIB website for more details and examples.
EMOSLIB also provides two command-line tools for using interpolation. Assuming a recent version of the EMOS library, there are two tools that can be used.
In the 'bin' directory there is a command 'emos_tool' which can be used as:
bin/emos_tool example
emos_tool --regular=256 [--area="40/-10/31/20"] in.grib out.grib
The grid specified for the --regular option follows the grid naming convention for EMOSLIB here: Reduced Gaussian Grids.
Another command can be found in the 'tools' directory. This allows the interpolation function to be specified and is more flexible:
tools/int --INTOUT:gridname=F256 --INTOUT:area="40/-10/31/20" --input=1.grib --output=2.grib --intf2
Here 'F256' means 'full-grid' not reduced, and --intf2 is the EMOSLIB interpolation function to be used.
cdo -R option does not work with GRIB-2 fields to convert to regular grid
CDO's -R option, to convert from reduced Gaussian grid to regular Gaussian grid, only works with GRIB 1 format as the CGRIBEX decoder this uses does not work with GRIB-2 (see cdo man page). This is a problem as multi-level output from OpenIFS is encoded as GRIB-2 data.
The preferred way to deal with this is to use the setgridtype operator as described above:
cdo -f nc setgridtype,regular <input grib> <output netcdf>
However, if this does not work for any reason, a workaround is to temporarily change the edition number to 1 of the GRIB file. Use the grib_set command (from ecCodes) to change the GRIB edition number for all messages:
Workaround to convert GRIB 2 to regular grid
grib_set -s editionNumber=1 in.grb in_1.grbcdo -R copy in_1.grb in_1_R.grbgrib_set -s editionNumber=2 in_1_R.grb in_2_R.grb
This does not actually convert the message to GRIB-1, it only changes the editionNumber. Any GRIB-2 specific elements are unaltered.
It's recommended that the editionNumber is changed back to 2 to ensure that the parameter names remain correct in any subsequent cdo / grib commands.
Workaround if using more than 128 levels
The workaround above will fail if the grib file contains field with more than 128 levels. This is because there are not enough bits available in the GRIB-1 parameter to encode the total number of model half levels (which would exceed 255).
In this case, the 'pv' GRIB parameter causes the problem (nothing to do with potential vorticity!). This is an array holding the half level values of the model's A & B coefficients that define the location of the levels.
The workaround above can be extended to delete this array while setting the edition number to 1, like this:
grib_set -s deletePV=1,editionNumber=1 in.grb in_1.grbcdo -R copy in_1.grb in_1_R.grbgrib_set -s editionNumber=2 in_1_R.grb in_2_R.grb
The deletePV option is known as a 'concept' rather than a parameter contained in the GRIB file itself. It ensures the PV array is deleted correctly by grib_set. Now the cdo regridding will work correctly, but remember to reset the editionNumber back to 2.
The A & B half level coefficients can be recovered from the original file by:
cdo vct in.grb > pv.txt
Parameter names are lost for GRIB-1 fields
ECMWF GRIB-1 use keys which may not be recognised by CDO because they are locally defined (e.g. the shortName key) and not defined in the WMO GRIB tables that CDO uses. This can cause parameter names to be lost or not recognised when using the CDO commands.
A workaround is to use the -t ecmwf option.This will make CDO use ECMWF parameter table 128 for the definitions of variables but 128 is only for GRIB 1. This will work for the surface fields which are encoded by IFS as GRIB 1, but not for the multi-level fields which are encoded in GRIB 2. Variable names become 'unknown' if -t ecmwf is used with the multi-level fields. It is best to omit it completely, even for surface fields, and only use it for GRIB 1 data if you get missing variable names after CDO has converted the data (see CDO documentation for more details).
cdo -t ecmwf -f nc copy mygrib1.grb mygrib1.nc
Do not use this option for GRIB-2 fields. It sets the GRIB table default to be specific to the GRIB-1 ECMWF tables. If problems persist, we recommend using grib_to_netcdf to convert to netCDF.
Thanks to Paul Dando of User Support for help with the contents of this page.
FAQs
How to convert GRIB to netCDF - OpenIFS? ›
A subtle difference is that netCDF/HDF/HDF-EOS are file formats while GRIB is a record format. Because netCDF/HDF/HDF-EOS are file formats there are rules on a file's contents. For example, a simple netCDF rule is that all variable names must be unique.
How to convert grib2 file to netCDF? ›- Size of netCDF files can be further reduced by compression e.g. cdo -f nc4c -z zip_6 copy h14_2019053000_r.grib h14_2019053000_compressed.nc.
- To convert multiple files from grib to netCDF, you can loop over all the files in the directory and apply the commands above e.g.
A subtle difference is that netCDF/HDF/HDF-EOS are file formats while GRIB is a record format. Because netCDF/HDF/HDF-EOS are file formats there are rules on a file's contents. For example, a simple netCDF rule is that all variable names must be unique.
How to read GRIB files in Python? ›To read GRIB data, you can use xarray. load_dataset . The only extra code you need is to specify the engine as cfgrib .
How do I access GRIB files? ›- Panoply by NASA.
- MetView by ECMWF.
- Integrated Data Viewer (IDV) by UCAR unidata.
- zyGRIB.
- ArcGIS by ESRI.
- create the file - Specify the name, optionally the format: classic (the default), 64bit-offset, or 64-bit data.
- define metadata - Specify the names and types of dimensions, data variables, and attributes.
- write data - Write arrays of data from program variables to the netCDF file.
The format is an open standard. NetCDF Classic and 64-bit Offset Format are an international standard of the Open Geospatial Consortium.
How do I write a netCDF file? ›The easiest way to create a netCDF file is to (1) write all the header data (the name, dimensions, variable and attribute specifications, and the values of any coordinate variables) to a CDL file, (2) convert the CDL file to a netCDF file using ncgen, and (3) continue writing the main data arrays to this netCDF file.
What is the file name for netCDF? ›NetCDF files should have the file name extension " . nc ".
What is the difference between netCDF and GeoTIFF? ›GeoTIFF is a collection of 2D "images" or arrays. NetCDF is a general purpose storage for multidimensional arrays. But if you store the arrays in the same way in netCDF as they are in GeoTIFF, you will get the same performance, more or less.
How to read NetCDF file in Python? ›
- import netCDF4 import numpy as np.
- f = netCDF4. Dataset('../../data/rtofs_glo_3dz_f006_6hrly_reg3.nc')
- print(f. variables. ...
- temp = f. variables['temperature'] # temperature variable print(temp)
- for d in f. dimensions. ...
- temp. dimensions.
- temp.
- mt = f. variables['MT'] depth = f.
- Load files containing GRIB2 messages into a Python program.
- Inspect the GRIB2 data to understand which weather variables are included.
- Crop the GRIB2 data to the area defined by a GeoJSON file input.
- Convert the transformed GRIB2 data into a CSV output file for further analysis and visualization.
GRIB2 is more complex than GRIB1 offering a basis to represent a lot more products in WMO standard (e.g. ensemble products) than GRIB1. GRIB_API/EcCodes is a GRIB coding software (from ECMWF) with a key – value approach, enabling the user to code GRIB without detailed knowledge about its structure.
What is a GRIB file format? ›GRIB is a file format for the storage and transport of gridded meteorological data, such as Numerical Weather Prediction model output. It is designed to be self-describing, compact and portable across computer architectures. The GRIB standard was designed and is maintained by the World Meteorological Organization.
What does GRIB file stand for? ›GRIB (GRIdded Binary or General Regularly-distributed Information in Binary form) is a concise data format commonly used in meteorology to store historical and forecast weather data.
How do I open a GRIB file in grads? ›In order to read grib files, you need to make a control (ctl) file for that grib file using wgrib2. Then make index files (idx) for that ctl. Then you will be able to read the control file of your data.
How do I write a NetCDF file in python? ›To write data a netCDF variable object, just treat it like a numpy array and assign values to a slice. You can just treat a netCDF Variable object like a numpy array and assign values to it. The above writes the whole 3D variable all at once, but you can write it a slice at a time instead.
What data is in a NetCDF file? ›NetCDF (network Common Data Form) is a file format for storing multidimensional scientific data (variables) such as temperature, humidity, pressure, wind speed, and direction. Each of these variables can be displayed through a dimension (such as time) in ArcGIS by making a layer or table view from the netCDF file.
How is data stored in NetCDF? ›The data in a netCDF file is stored in the form of arrays. For example, temperature varying over time at a location is stored as a one-dimensional array. Temperature over an area for a given time is stored as a two-dimensional array.
What is the difference between CDF and netCDF? ›NetCDF supports named dimensions (i.e., TEMP[x, y, ...]) whereas CDF utilizes the traditional logical (i.e., TEMP[true, true, ...]) method of indicating dimensionality. CDF supports both multi- and single file filing systems whereas netCDF supports only single file filing systems.
What software read netCDF? ›
Panoply plots geo-referenced and other arrays from netCDF, HDF, GRIB, and other datasets. Panoply is a cross-platform application that runs on Macintosh, Windows, Linux and other desktop computers. Panoply requires that your computer has have had a compatible Java 11 (or later version) JRE or JDK installed.
What is the difference between HDF5 and netCDF? ›The results of the benchmark show that HDF5 is fastest in reading or writing to a dataset, netCDF4 is fastest in creating or opening a dataset, and Zarr generally trails right behind HDF5 in performance.
Can you open NetCDF in Excel? ›CDO (https://code.mpimet.mpg.de/projects/cdo/files), I think is very efficient for the analysis of data in NetCDF format. CDO comes with detailed operator description and examples (https://code.mpimet.mpg.de/projects/cdo/embedded/cdo.pdf) . Yeah you can read netcdf file in excel...
How do I create a NetCDF file in ArcGIS? ›- Start ArcMap.
- Click OK on the ArcMap startup dialog box.
- Open the Make NetCDF Raster Layer tool. ...
- For the Input netCDF File value, type or browse to C:\NetCDF\temperature.nc.
- Accept default values for Variable (tmin), X Dimension (lon), and Y Dimension (lat) parameters.
The netCDF libraries support a machine-independent format for representing scientific data. Together, the interfaces, libraries, and format support the creation, access, and sharing of scientific data.
How do I open and read a netCDF file? ›- open the file - Specify the file name and whether you want read-write or read-only access.
- read variable or attribute data - Read the data or attributes of interest.
- close the file - Release all resources associated with this file.
The data types supported by netCDF are character, byte, short, long, float, and double. These data types are maintained in the netCDF raster layer, feature layer, or table created from a netCDF file.
How to install netCDF libraries? ›- Download the latest NetCDF4 installer from the NetCDF-C Windows Libraries page.
- Install the executable.
- Make sure to add the bin folder of the package you have extracted, to the PATH environment variable.
NetCDF is Self Describing
One of the biggest benefits of working with a data type like netCDF is that it is self-describing. This means that all of the metadata needed to work with the data is often contained within the netCDF file (the . nc file) itself. Netcdf is a hierarchical data format.
- Click the Analysis tab.
- Click Tools.
- Type Make NetCDF Table View in the text box.
- Click Make NetCDF Table View in the returned list to open the tool.
- Type the name in the Input netCDF File, or alternatively, click the browse button to navigate to the input file.
Is netCDF a HDF5? ›
The netCDF-4/HDF5 file format enables the expansion of the netCDF model, libraries, and machine-independent data format for geoscience data. Together the netCDF interfaces, libraries, and formats support the creation, access, and sharing of scientific data.
What is an example of NetCDF data? ›Network common data form (NetCDF) is commonly used to store multidimensional geographic data. Some examples of these data are temperature, precipitation, and wind speed.
Is NetCDF extractor free? ›This tool is flexible to run for various datasets such as CMIP5 models, AgMERRA datasets, Aphrodite, CRU, CORDEX, and etc. In fact, this tool is NetCDF viewer, NetCDF converter, and NetCDF extractor. You can use it free as a NetCDF viewer.
How do I convert NC to CSV? ›- Install ncdf4 and lubridate packages.
- Load your NetCDF file.
- Extract the coordinates.
- Time conversion.
- Extract the variables.
- Export result as CSV.
To write a grib message, you need a "template", a grib message with the correct grid and most of the metadata. Often these templates are created interactively using wgrib2. The procedure is to take an existing grib message, and then modify it to have the correct grid and metadata.
How do I get started with GRIB2 weather data and Python? ›- Load global weather forecast files containing GRIB2 messages into a Python program.
- Inspect the GRIB2 data to understand which weather variables are included.
- Filter the GRIB2 data to just one weather variable of interest.
- Crop the GRIB2 data to a specific area using a geospatial bounding box.
To write a grib message (record), you run the command g2grb (short for grads2grib). To write write two grib messages to a file, you run g2grb twice. The only difference is that for the second (and following writes), you have to prefix the file name with a plus sign '+'.
How often are GRIB files updated? ›The forecasts are generated daily at 0015, 0615, 1215, 1815 GMT for every region of the world. GRIB forecasts are based on the National Weather Service (NOAA), Wave Watch III model forecasts every 6 hours for up to 7 days into the future.
What is a GRIB2 file extension? ›A GRIB2 file is a binary file saved in the World Meteorological Organization (WMO) format. It contains gridded meteorological data and is used by meterological centers to store and exchange gridded fields.
How big is a GRIB file? ›GRIB files delivered by email can be quite an economic way of receiving weather data at sea. Files sizes might be circa 8 - 15 KB for an area covering the Mediterranean Sea.
Who uses the GRIB and what is it for? ›
GRIB is used by the operational meteorological centers for storage and the exchange of gridded fields. GRIB's major advantages are files are typically 1/2 to 1/3 of the size of normal binary files (floats), the fields are self describing, and GRIB is an open, international standard.
How do you read GRIB arrows? ›Wind barbs indicate both the wind speed and wind direction. The barb line represents wind direction by pointing to the direction where the wind is blowing from. The tails extending from the barb are an indication of wind speed; each half of a tail represents 5 knots of wind.
How do I open a GRIB file in ArcGIS? ›You can display GRIB, HDF, or NetCDF data in a map in ArcGIS Pro using the Add Multidimensional Raster Layers dialog box.
How do I open GrADS in Linux? ›- data file, know the content of the file, display a variable, and exit grads. ✓ In the terminal type grads and press enter.
- GrADS will prompt you with a landscape vs. ...
- Just press enter. ...
- open on your console (on the right). ...
- GrADS -- this window will need to be made the 'active' window and you will not want to.
GRIB Edition 2 (Requires Acrobat Reader to view) (GRIB2): the GRIB2 format represents an enlarging and a significant modernization of the GRIB standard. It is being phased in by the ECMWF and some national Numerical Weather Prediction institutions, notably in the US and Europe.
How to create netCDF file in python? ›To write data a netCDF variable object, just treat it like a numpy array and assign values to a slice. You can just treat a netCDF Variable object like a numpy array and assign values to it. The above writes the whole 3D variable all at once, but you can write it a slice at a time instead.
What is the GRIB file name? ›What is GRIB? GRIB is a WMO format for gridded data. GRIB is used by the operational meteorological centers for storage and the exchange of gridded fields.
How to process NetCDF data in Python? ›- import netCDF4 import numpy as np.
- f = netCDF4. Dataset('../../data/rtofs_glo_3dz_f006_6hrly_reg3.nc')
- print(f. variables. ...
- temp = f. variables['temperature'] # temperature variable print(temp)
- for d in f. dimensions. ...
- temp. dimensions.
- temp.
- mt = f. variables['MT'] depth = f.
- Download the latest NetCDF4 installer from the NetCDF-C Windows Libraries page.
- Install the executable.
- Make sure to add the bin folder of the package you have extracted, to the PATH environment variable.
NetCDF (network Common Data Form) is a file format for storing multidimensional scientific data (variables) such as temperature, humidity, pressure, wind speed, and direction. Each of these variables can be displayed through a dimension (such as time) in ArcGIS by making a layer or table view from the netCDF file.
Can you open netCDF in Excel? ›
CDO (https://code.mpimet.mpg.de/projects/cdo/files), I think is very efficient for the analysis of data in NetCDF format. CDO comes with detailed operator description and examples (https://code.mpimet.mpg.de/projects/cdo/embedded/cdo.pdf) . Yeah you can read netcdf file in excel...