Raging winds on Mars

On Mars, dust devils and winds reach speeds of up to 160 km/h and are therefore faster than previously assumed: This shows a study by an international research team led by the University of Bern. The researchers analyzed images taken by the Bernese Mars camera CaSSIS and the stereo camera HRSC with the help of machine learning. The study provides a valuable data basis for a better understanding of atmospheric dynamics, which is important for better climate models and future Mars missions.

Despite the very thin Martian atmosphere, there are also winds on Mars that are central to the climate and the distribution of dust. The wind movements and the whirling up of dust also create so-called dust devils, rotating columns of dust and air that move across the surface. In images of Mars, the wind itself is invisible, but dust devils are clearly visible. Due to their movement, they are valuable indicators for researchers to determine the otherwise invisible winds.

A new study led by Dr. Valentin Bickel from the Center for Space and Habitability at the University of Bern shows that the dust devils and the winds that surround them reach significantly higher speeds than previously assumed. The stronger winds could be responsible for a large part of the dust uplift on Mars, which in turn has a major influence on the weather and climate of Mars. The study, in which researchers from the Department of Space Research and Planetology at the Physics Institute at the University of Bern, the Open University in the UK and the German Aerospace Center (DLR) are also involved, has just been published in the journal Science Advances.

Movement of dust devils studied with the help of deep learning

"Using a state-of-the-art deep learning approach, we were able to identify dust devils in over 50,000 satellite images," explains first author Valentin Bickel. The team used images from the Bern-based Mars camera CaSSIS (Color and Stereo Surface Imaging System) and the stereo camera HRSC (High Resolution Stereo Camera). CaSSIS is on board the European Space Agency’s (ESA) ExoMars Trace Gas Orbiter, while the HRSC camera is on board the ESA orbiter Mars Express. "Our study is therefore based exclusively on data from European Mars exploration," Bickel continues.

In a next step, the research team examined stereo images for around 300 of the identified dust devils in order to measure their directions of movement and velocities. Co-author Nicolas Thomas, under whose leadership the CaSSIS camera system was developed and built at the University of Bern and which is funded by SERI's Swiss Space Office through ESA's PRODEX program (see info box), explains: "Stereo images are images of the same spot on the surface of Mars, but taken a few seconds apart. These images can therefore be used to measure the movement of dust devils." Bickel emphasizes: "If you put the stereo images together in a sequence, you can observe how dynamically the dust devils move across the surface." 

Winds on Mars stronger than previously assumed

The results show that the dust devils and the winds surrounding them on Mars can reach speeds of up to 44 m/s, i.e. around 160 km/h, across the entire planet, which is much faster than previously assumed (previous measurements on the surface had shown that winds mostly remain below 50 km/h and – in rare cases – can reach a maximum of 100 km/h). The high wind speed in turn influences the dust cycle on the Red Planet: "These strong, straight-line winds are very likely to bring a considerable amount of dust into the Martian atmosphere – much more than previously assumed," says Bickel. He continues: "Our data show where and when the winds on Mars seem to be strong enough to lift dust from the surface. This is the first time that such findings are available on a global scale for a period of around two decades."

Future Mars missions can benefit from the research results

The results obtained are also particularly important for future Mars missions. "A better understanding of the wind conditions on Mars is crucial for the planning and execution of future landed missions," explains Daniela Tirsch from the Institute of Space Research at the German Aerospace Center (DLR) and co-author of the study. "With the help of the new findings on wind dynamics, we can model the Martian atmosphere and the associated surface processes more precisely," Tirsch continues. These models are essential to better assess risks for future missions and adapt technical systems accordingly. The new study thus provides important findings for a number of research areas on Mars, such as research into the formation of dunes and slope streaks, as well as the creation of weather and climate models of Mars.

The researchers plan to further intensify the observations of dust devils and supplement the data obtained with targeted and coordinated observations of dust devils using CaSSIS and HRSC. "In the long term, our research should help to make the planning of Mars missions more efficient," concludes Bickel.

Publication details:

Valentin T. Bickel, Miguel Almeida, Matthew Read, Antonia Schriever, Daniela Tirsch, Ernst Hauber, Klaus Gwinner, Nicolas Thomas, Thomas Roatsch (2025). Dust Devil Migration Patterns Reveal Strong Near-surface Winds across Mars. Science Advances. https://www.science.org/doi/10.1126/sciadv.adw5170
DOI: 10.1126/sciadv.adw5170

Support of the SERI / Swiss Space Office

CaSSIS is a project of the University of Bern and funded through the Swiss Space Office via the European Space Agency's PRODEX programme. The instrument hardware development was also supported by the Italian Space Agency (ASI), INAF/Astronomical Observatory of Padova, and the Space Research Center (CBK) in Warsaw. For all instruments developed in Switzerland, major contributions and/or partial deliveries come from Swiss industry. The PRODEX programme, under which scientific instruments or sub-systems are provided, requires industrial participation and thus promotes knowledge and technology transfer between universities and industry and gives Switzerland a structural competitive advantage as a business location – not least thanks to spill-over effects on other sectors of the participating companies. Swiss participation in ESA programmes enables Swiss players from science and industry to position themselves ideally in ESA activities in this field.
More information on CaSSIS: https://www.cassis.unibe.ch/

Center for Space and Habitability (CSH)

The Center for Space and Habitability (CSH) was established in 2011 and fosters interdisciplinary research across Earth and planetary sciences, the search for life in our Universe, philosophy of science and biomedical research. The CSH is part of a rich scientific environment, at the local, national and international levels.

The CSH connects research groups located at different institutes and faculties of the University of Bern to trigger curiosity-driven research and cross-fertilization of ideas. At the national level, the CSH is an important partner of the National Center for Competence in Research (NCCR) PlanetS created in 2014. Internationally, the CSH is involved in the scientific exploitation a number of large-scale projects and missions, such as CHEOPS, the first Swiss-led satellite, the James Webb Space Telescope (JWST) and the Saint-Ex astronomical observatory.

The CSH runs a number of programs in order to stimulate interdisciplinary research and support early career researchers, such as the CSH and Bernoulli Fellowships as well as the Visiting Professorship program. The CSH also runs a number of interaction mechanisms to encourage dialogue and exchange of ideas across all fields. The CSH also promotes equality and diversity at the University to foster an inclusive workplace.
More information: https://www.csh.unibe.ch/index_eng.html  

Bernese space exploration: With the world’s elite since the first moon landing

When the second man, "Buzz" Aldrin, stepped out of the lunar module on July 21, 1969, the first task he did was to set up the Bernese Solar Wind Composition experiment (SWC) also known as the “solar wind sail” by planting it in the ground of the moon, even before the American flag. This experiment, which was planned, built and the results analyzed by Prof. Dr. Johannes Geiss and his team from the Physics Institute of the University of Bern, was the first great highlight in the history of Bernese space exploration. Ever since Bernese space exploration has been among the world’s elite, and the University of Bern has been participating in space missions of the major space organizations, such as ESA, NASA, and JAXA. With CHEOPS the University of Bern shares responsibility with ESA for a whole mission. In addition, Bernese researchers are among the world leaders when it comes to models and simulations of the formation and development of planets. The successful work of the Space Research and Planetary Sciences Division (WP) from the Physics Institute of the University of Bern was consolidated by the foundation of a university competence center, the Center for Space and Habitability (CSH). The Swiss National Fund also awarded the University of Bern the National Center of Competence in Research (NCCR) PlanetS, which it manages together with the University of Geneva.

2025/10/08