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2 - Prerequisites

• Learn more about the family of ERA5 datasets, and browse through the ERA5 data documentation and ERA5-Land data documentation.
• CDS account - If you do not yet have a CDS account, please create one HERE.
• Accept the Copernicus licence by creating a test download using the CDS Download web form interface (see below).

3 - Downloading online ERA5 family data through the CDS web interface

1. Go to the C3S climate data store (CDS).
2. Type  'ERA5' in the search box.
3. Follow the ERA5 dataset title link of interest (there will be many more hits).

4. Currently there are eight online ERA5 and two ERA5-Land catalogue entries  

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   title Show ERA5 catalogue entries in the CDS
   ERA5 hourly data on single levels from 1940 to present ERA5 monthly averaged data on single levels from 1940 to present ERA5 hourly data on pressure levels from 1940 to present ERA5 monthly averaged data on pressure levels from 1940 to present ERA5-Land hourly data from 1950 to present ERA5-Land monthly averaged data from 1950 to present

   
   

5. Each of these dataset catalogue entries includes the following tabs:
   • Overview . This gives a description of the selected dataset and metadata information (e.g. spatial details, file format, variables, etc).
   • Documentation . This provides links to detailed documentation about the dataset.
     
   • Download data . This is a download web form.
6. Go to the Download data tab to make your selection for ERA5 data retrieval. Using this web interface, you can:
   • make selections as per your requirements. For your convenience only valid combinations will show; invalid combinations are greyed out interactively.

   • accept the data licence in the Terms of use section (in case you had not yet accepted it). You will only see this section after you have logged in.

     Note
     You will need to do this regardless whether you are accessing data through the web interface or through the CDS API (see below).

     
     

7. Click on the button Submit Form at the bottom right to submit your data request (you must be logged in and have accepted the terms and conditions before submitting your request).

8. You will now be redirected to the Your requests page.

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1. This is Python based.
   • This may require some basic knowledge of Python. However, in most cases common-sense adaptions of example requests obtained from the web interface should be sufficient.
2. Install the CDS API:
   • this may require some basic knowledge of pip, in particular know how to install packages on your local machine using pip.
   • On linux or on cygwin, please follow the instructions HERE.
   • Windows users may follow the instructions HERE instead.
   • Mac users may follow the instructions HERE.
3. You are recommended to use the latest release of package CDS API.
4. Run CDS API requests, either interactively or in batch mode.

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1. Build a basic CDS API request.

   • You can use the CDS web interface to help you build your CDS API download script.

   • In the Download data  tab, make some selections, then click the button Show API request at the bottom left and you will be presented with the script.

   • Copy and paste this to your preferred text editor.

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     title Basic CDS API script example (for ERA5 1940-present) to download temperature geopotential at a given pressure level, 1000 hPa is shown HERE.
     Code Block language text py #!/usr/bin/env python import cdsapi cclient = cdsapi.Client() c.retrieve( dataset = 'reanalysis-era5-pressure-levels', request = { 'product_type': ['reanalysis'], 'variable': ['temperaturegeopotential'], 'pressure_level'year': ['10002024'], 'yearmonth': ['200803'], 'monthday': ['01'], 'daytime': ['0113:00'], 'time'pressure_level': ['12:001000'], 'data_format': 'netcdfgrib', # Supported format: grib and netcdf. Default: grib }, target = 'download.nc') grib' # Output file. Adapt as you wish. client.retrieve(dataset, request, target)

     
     

2. Refine your CDS API script for ERA5 data listed in CDS for optional post-processing.
   
   • For a different grid resolution, use the key 'grid'.
   • Please note that the ERA5 native grid of online CDS is 0.25°x0.25° (atmosphere), 0.5°x0.5° (ocean waves), mean, spread and members: 0.5°x0.5° (atmosphere), 1°x1° (ocean waves). ERA5-Land: 0.1°x0.1°. So this will be returned by default.

   • 
     

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     title Click here for a sample script (for ERA5 1940-present) that downloads temperature at a given pressure level at 1000 hPa for a geographical subset of the data and specified grid
     Code Block language text py #!/usr/bin/env python import cdsapi cclient = cdsapi.Client() c.retrieve( dataset = 'reanalysis-era5-pressure-levels', { 'product_type': 'reanalysis', request = { 'variableproduct_type': ['temperaturereanalysis'], 'pressure_level'variable': ['1000geopotential'], 'year': ['20082024'], 'month': ['0103'], 'day': ['01'], 'time': ['1213:00'], 'format'pressure_level': ['netcdf1000'], 'data_format': 'grib', # Supported format: grib and netcdf. Default: grib 'area' : [60, -10, 50, 2], # North, West, South, East. Default: global 'grid' : [1.0, 1.0], # Latitude/longitude grid. Default: 0.25 x 0.25 }, target = 'era5_temperature_sub_area.nc')download.grib' # Output file. Adapt as you wish. client.retrieve(dataset, request, target)

     
     

To retrieve data efficiently using the CDS API please have a look at the efficiency tips section on CDS documentation.

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You can discover the ERA5-complete structure (1940-present) and learn how to build a CDS API request by following these steps:

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