Synda

What is synda?

Synda is a command line tool to search and download files from the Earth System Grid Federation (ESGF) archive. Synda is a useful tool if you need to download Climate Model Intercomparison Project Phase 6 (CMIP6) data in particular. Synda supports different download protocols (e.g. HTTPS) and can download files in parallel.

We'll describe the steps to install and use synda on Mahuika or Maui_ancil.

How to install synda

1. Load Anaconda3

module load Anaconda3

2. Create a conda environment and activate the environment

conda create --prefix=<SYNDA_ENV>

where <SYNDA_ENV> is a directory of your choice. Activate your new environment

conda activate <SYNDA_ENV>

3. Install synda (currently version 3.10)

conda install -c IPSL synda

4. Configure synda

Set the ST_HOME environment variable and populate $ST_HOME, for instance

export ST_HOME=/nesi/nobackup/<YOUR PROJECT>/synda_home

Note: you may want to add the above "export ST_HOME=<...>" somewhere near the bottom of your ~/.bashrc file.

To search and download climate model data you will in addition need to create an account on one or more of the ESGF nodes, e.g. https://esgf-node.llnl.gov/projects/esgf-llnl/. This will require you to provide a user name (USER_NAME) and a password - you will receive an openID in return. Copy your openID string as you will need later.

To configure and store your ESGF credentials, type

synda -h
synda check-env

Paste in the openID you received when creating your ESGF account. If you created an account on esgf-node.llnl.gov then your openID will be:

openID url: https://esgf-node.llnl.gov/esgf-idp/openid/USER_NAME

(USER_NAME is the user name you chose when creating the account). You can change your default configuration by editing $ST_HOME/conf/sdt.conf. I have

indexes = esgf-node.llnl.gov
default_index = esgf-node.llnl.gov

Example

Find all the datasets for given ocean surface temperature ("tos"), variant label ("r1i1p1f1") produced by institution "NOAA-GFDL" for historical data and table Id "Omon":

synda search project=CMIP6 realm=ocean variable=tos variant_label=r1i1p1f1 institution_id=NOAA-GFDL table_id=Omon experiment_id=historical

This will return

new  CMIP6.CMIP.NOAA-GFDL.GFDL-CM4.historical.r1i1p1f1.Omon.tos.gn.v20180701
new  CMIP6.CMIP.NOAA-GFDL.GFDL-CM4.historical.r1i1p1f1.Omon.tos.gr.v20180701
new  CMIP6.CMIP.NOAA-GFDL.GFDL-ESM4.historical.r1i1p1f1.Omon.tos.gn.v20190726
new  CMIP6.CMIP.NOAA-GFDL.GFDL-ESM4.historical.r1i1p1f1.Omon.tos.gr.v20190726

Choose one of the datasets. To find out how big the dataset is, type: 

synda stat CMIP6.CMIP.NOAA-GFDL.GFDL-ESM4.historical.r1i1p1f1.Omon.tos.gr.v20190726

which returns

Total files count: 9
New files count: 9
Total size: 262.8 MB
New files size: 262.8 MB

To download the dataset, type

synda get CMIP6.CMIP.NOAA-GFDL.GFDL-CM4.historical.r1i1p1f1.Omon.tos.gn.v2018070

The datasets (NetCDF files) will be downloaded locally in your directory.

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