CODEWITHSUNDEEP
pythondownloadesgf
Dee1999
Dee1999

Reputation: 55

Downloading CMIP6 data for a specific area

By default, the CMIP6 netcdf data downloaded from any of the different ESGF portals cover the entire globe. Is there a way to download CMIP6 for a box (e.g., with bounds 20°W,20°E and 15°S,25°N) encompassing a particular region of the world?

Upvotes: 1

Views: 1291

Answers (3)

Abel Callejo
Abel Callejo

Reputation: 14939

You can download CMIP6 data for a specific area by getting it from the Climate Change Service of the European Union instead of getting it from ESGF. They have a download form there where you can specify the extent or boundaries of the specified area you want to download. You will then receive the NetCDF data from there.

In my case, I was able to download data for various regions such as, South-East Asia, Africa, and Philippines with no problems.

If you want to know more details about it, you may see my article on how to download the CMIP6 projected climate change weather data. Alternatively, you may also just watch this tutorial on YouTube.

Upvotes: 0

ClimateUnboxed
ClimateUnboxed

Reputation: 8087

As a modification to Robert's anwer, if you don't want to calculate the i and j indices, I think you can specify the lat lon range directly using a decimal point:

ncks -d lat,-15.,25. -d lon,340.,20. http://aims3.llnl.gov/thredds/dodsC/css03_data/CMIP6/CMIP/MOHC/UKESM1-0-LL/historical/r1i1p1f2/Omon/tos/gn/v20190406/tos_Omon_UKESM1-0-LL_historical_r1i1p1f2_gn_185001-194912.nc outfile.nc

Be careful with how you specify the longitude when you have wrapped coordinates across lon=0, as specified in this answer to Robert's own question here. :-)

Upvotes: 0

Robert Wilson
Robert Wilson

Reputation: 3407

This can be done using the opendap options available over ESGF. This can be cropped easily on the command line using NCO. An example, for a different region, is below:

ncks -d i,260,305 -d j,240,290 http://aims3.llnl.gov/thredds/dodsC/css03_data/CMIP6/CMIP/MOHC/UKESM1-0-LL/historical/r1i1p1f2/Omon/tos/gn/v20190406/tos_Omon_UKESM1-0-LL_historical_r1i1p1f2_gn_185001-194912.nc outfile.nc

CMIP6 grids are in no way consistent, so you will need to create a different NCO call (or xarray or whatever you choose to use). If you are working with a lot of different models, this might take some time.

If you already have urls for downloading, you should be able to convert them to opendap urls as follows:

ff.replace("fileServer","dodsC")

where ff is the url.

Upvotes: 4

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