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.
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 -n syndaenv
Activate your new environment in a separate window (otherwise you will get a conda init error),
conda activate syndaenv
3. Install synda
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 synda -h
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 store your ESGF credentials, type
Pate 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 (USER_NAME is the user name you chose when creating the account):
openID url: https://esgf-node.llnl.gov/esgf-idp/openid/USER_NAME
Find all the datasets for ocean surface temperature ("tos") available at a monthly frequency
synda search CMIP6 variable=tos realm=ocean frequency=mon
This will return many potential datasets. Choose one of the datasets. Next we want to find out how big the dataset is
synda stat CMIP6.AerChemMIP.CNRM-CERFACS.CNRM-ESM2-1.hist-1950HC.r1i1p1f2.Omon.tos.gn.v20190621
New files size: 161.2 MB
To download the data, type
synda get CMIP6.AerChemMIP.CNRM-CERFACS.CNRM-ESM2-1.hist-1950HC.r1i1p1f2.Omon.tos.gn.v20190621
The datasets (NetCDF files) will be downloaded locally in your directory.