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XIOS training sessions

Mar 15, 2021 02:00 PM to Apr 16, 2021 05:00 PM (Europe/Vienna / UTC100)
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The XIOS team will open two online training sessions on XIOS and dr2xml. 

The first session will take place from 2pm to 5pm CET on March 15th to 19th 2021 and the second one is planned for April 12th - 16th 2021.

This training session will include presentations of XIOS & dr2xml and most importantly several hands-on exercises.

A dedicated webpage for this training is available here and information will be updated regularly including a more detailed program of the training and slides.

The slides used for the training sessions are available here !

What is XIOS:

The climate simulation models launched on super-computers produce a significant amount of data. At this scale, the management of output files and post-treatment on data become the  performance bottleneck for those climate models. In order to generate efficiently the output from models while taking advantage of the calculate resources, Institut Pierre Simon Laplace has launched the XIOS project.

XIOS is a library dedicated to generate efficiently and easily the parallel input/output of climate models. It uses a client-server methodology in which clients (or models) will simulate the physics and send data asynchronously to servers. It is the XIOS servers who are in charge of writing data to files. In this way, we can smooth the I/O peaks by sending to servers a constant data flux all along the simulations and the I/O is overlapped with calculates.

What's more, XIOS provides multiple functionalities which allow an "in situ" data post-treatment. For example, we can read the data from models, operate transformations on those data, combine data from different source models, and send results to multiple output files. All these operations are defined from an external XML file with a very compact and flexible way. Any modifications in this XML file will not require re-compilation of XIOS or models.

XIOS is written in C++ and uses MPI for asynchronous communications between clients and servers. NETCDF, HDF5, and MPIIO are also used in XIOS for efficient file writing.

What is dr2xml:

DR2XML is a python package useful for climate models whose I/O are handled by XIOS. It has been originally designed to facilitate the configuration of XIOS (automatic generation of XML files) so as to fully satisfy the CMIP6 DataRequest. With DR2XML, the NetCDF files output by the model are directly CMOR3 compliant.  Some extended functionalities were also developed so that DR2XML enables the user to set up his own Data Request. Consequently DR2XML can be used to customize the official CMIP6 DR or even to work off the CMIP6 framework, but benefiting from the CF-NetCDF, CMOR, and CMIP6 standards (file naming convention, file structure, variable definitions, file and variable attributes, etc.).

Registration to the training:

If you are interested in following the XIOS&dr2xml training, please fill up the registration form.

By applying to the XIOS virtual trainings, you agree that the IS-ENES3 project and its selection committee will collect your personal data according to the IS-ENES3 data privacy policy: Your data will only be used in the purpose of the organization of the IS-ENES3 XIOS virtual trainings. If you want to modify or erase your personal data, please send an email to

If you have any questions about this training, please contact Yushan Wang (


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IS-ENES3 has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 824084