Clouds, weather, global climate

It started with clouds: “They not only look nice, but clouds are also very interesting and challenging to understand because of the scales and processes they encompass,” says Mirjana Sakradzija. Since October 2023, Sakradzija has been Professor of Physical Geography and Land-Atmosphere Coupling at the Faculty of Geosciences at LMU. Or a professional cloud-watcher, you might say. At least, the shape-shifting structures of water vapor between heaven and Earth play a major role in her research.

Intriguingly, clouds represent a link between small-scale phenomena and the grand processes that shape our planet – between local weather and global climate. The scale of clouds ranges from a few meters to kilometers, they organize into systems hundreds of kilometers wide, while their impact reaches far beyond. From fueling thunderstorms over land to intensifying the planetary-scale circulations over the ocean, the complex cloud fields determine our weather forecasts and climate simulations.

Cloud-watching for science

This aspect – the connection between small and large – is something that fascinates Sakradzija: “I’m seeking to understand the local weather processes that then form the local climate, and then influence the larger and longer-term scales.” She wants to understand, for example, how convective clouds (the typical clouds you see on warm summer days) affect the heat and moisture exchange between land and atmosphere and thus larger-scale phenomena such as convective storms and the development of heatwaves.

Clouds have been puzzling climate and atmosphere experts for decades. “We’re dealing with extremely unpredictable processes,” explains the atmospheric researcher. Furthermore, “the very fine-scale interactions between land and the atmosphere are practically invisible to ordinary weather and climate models.” This introduces biases. “We’re researching in order to better represent these processes in numerical models so that we can then create more reliable forecasts and projections.” Shallow cumulus clouds are one of the largest sources of uncertainty in climate projections. They are at the center of research today because this gap in our knowledge entails major uncertainties for both weather and climate. Through her work, Sakradzija wants to close this gap.

Is the future in the clouds?

“I remember during my PhD, all the excitement when I finally understood why the statistics looked the way they looked.” This meant she was able to explain why the distribution of cloud sizes changes sometimes and what affects that change. “Once I was able to connect this physical understanding with the statistical representation – that was amazing!”

After studying physics and meteorology at Novi Sad in Serbia, Sakradzija undertook her doctorate at the Max Planck Institute for Meteorology in Hamburg, where she worked on clouds in numerical weather and climate models. “After my post-doc period, I moved to Germany’s national meteorological service in Offenbach, where I co-led the group on Boundary Layer Meteorology, which is located at the Goethe University in Frankfurt.”

Sakradzija has been at LMU since last year – although not in the physics department, but the geography department. “Nevertheless, I cooperate closely with colleagues from the meteorology group. And not only since I came to LMU, but since I arrived in Germany in 2011.” Indeed, her PhD thesis was inspired by the work of Professor George Craig from the Meteorological Institute at LMU. She views the close links between different specialist departments and groups as a major advantage of the research environment at LMU. “The strong connection to social sciences would probably not be possible in a different setting,” she says, alluding primarily to the fact that the research spectrum in the geography department includes and brings together natural and social scientific elements.

At the geography department, she also gets the opportunity to directly use the research findings for the benefit of society. “We have the research on carbon dioxide removal, which is closely related to land-atmosphere interactions. The plan is to do more research on how the changes in land use and land cover impact the clouds and climate, but also how we can benefit from better land management to mitigate and adapt to climate change.”