Capturing the beauty of the sky is a beloved hobby for many people on Earth, but the allure of atmospheric phenomena extends to other planets as well. Recently, scientists unveiled a remarkable “cloud atlas” for Mars, a comprehensive database featuring two decades’ worth of imagery showcasing clouds and storms on the red planet.
This cloud atlas is now accessible online, allowing users to explore a variety of Martian weather images captured by the Mars Express spacecraft. This mission by the European Space Agency has been orbiting Mars since 2005, utilizing its High Resolution Stereo Camera (HRSC) to document numerous cloud formations.
“The clouds we observe on Mars are as varied and intriguing as those found in Earth’s atmosphere, including some that are entirely unique to the Martian environment,” stated Daniela Tirsch from the German aerospace center DLR, who shared this research at the recent Europlanet Science Congress.
“One of my favorite phenomena is the spectacular ‘cloud streets’—linear formations of fluffy clouds that form around the massive Tharsis volcano and the northern lowlands during Mars’ spring and summer months. Although they resemble Earth’s cumulus clouds, they form under distinct atmospheric conditions and we also observe vast dust clouds that can span hundreds of kilometers—an occurrence we are fortunate not to experience on Earth.”
Beyond cloud streets, the images document dust-lifting events, where high winds and low gravity work together to raise particulate matter from the surface into the atmosphere. These dust storms can grow immensely large, occasionally enveloping the entire planet.
Other observed phenomena include Lee waves, which occur as clouds ripple in response to wind interacting with geological barriers like ridges and mountains, creating patterns similar to those observed on Earth.
Investigation of Martian clouds contributes vital knowledge about the planet’s atmosphere, weather patterns, and the regolith—dusty material that carpets its surface. This understanding is crucial not only for comprehending Mars’ current state and history, but also for future exploration efforts, including safely landing larger spacecraft on its surface.
Researchers are leveraging the cloud atlas to produce global cloud maps and analyze seasonal and regional variations, with ambitions to expand this database further. As Tirsch noted, “With the ESA extending the Mars Express mission at least until 2026, we can continue to update this invaluable database and deepen our understanding of the Martian atmosphere.”