Climate modeling with HPC – access for students

Hands-on experience on VSC-4

In the "Modeling and Data Analysis" class led by Blaž Gasparini the students received a trainee access to VSC-4, one of Austria's flagship supercomputers. Working directly on the supercomputer, the learning curve was steep — especially when the ongoing meteorologists encountered cryptic error messages while compiling model code or submitting jobs to the queue. But the students persevered, and in the end, each of them successfully ran their own climate simulations.

They worked with ICON, a highly versatile atmospheric model used for both weather forecasting and climate projections. After navigating the complexities of running the model and processing output files, the students were relieved to find that their simulated present-day climate actually resembled the real world. Given that ICON is a 400,000-line beast of a model, their initial skepticism was understandable.

Investigating global warming in a real-world context

After that, the fun part began: Instead of just analyzing pre-existing datasets, students tackled a real scientific question using their own climate model experiments: How much of global warming is due to the direct radiative impact of greenhouse gases versus the resulting increase in surface temperature? In reality, these effects are intertwined, making it difficult to separate them. But this is where climate models are indispensable — they let us ask "what if" questions and isolate specific processes.

The students ran two simulations: one where only greenhouse gases increased (without changing surface temperatures), and another where surface temperatures were artificially raised by 4°C. The first experiment showed only minor climate changes, while the second revealed dramatic shifts. In particular, they noticed that the troposphere — the atmospheric layer where weather happens — expanded in a warmer world. Thunderstorm clouds and other cloud layers formed at higher altitudes.

Increasing demand for the course

Ultimately, hands-on experience makes climate science more accessible. This year even more students joined the course than last year, showing a growing interest in scientific computing. Who knows — maybe some of them will push the boundaries of computational climate science in the near future!

A visit to VSC

To make the experience even more tangible, the students also had the opportunity to visit the VSC and see firsthand the high-performance computing cluster on which they ran their simulations. Seeing the physical infrastructure behind their work was a particularly memorable moment that was possible through the VSC team who opened the gates for the students.