A frosty Martian landscape 🔴 All over the image, dark dunes and dune fields can be found, in some areas covered by a thin frost layer. The dune fields take on a ‘yardang’-like shape, creating sharp ridges running parallel to the prevalent wind direction, guided by the morphology of the underlying surface. The dark dust is thought to originate from ancient, buried layers of volcanically erupted material. It can be found all over Mars and is easily spread by strong winds. Individual dark spots hint at a process specific to polar areas on Mars. Jets of carbon dioxide generated by the sublimation of ice into gas have burst through ice layers, ejecting a geyser-like fountain of dark dust that settles into these circular splotches. Monitoring these zones from orbit shows the processes that steadily alter the appearance of the surface in the polar regions on Mars. All over the image numerous large irregular-shaped sublimation features can be found arising from thawing pockets of ice. They have the appearance of (albeit empty) terrestrial lakes that have been scooped out of the landscape. A very pronounced example can be seen at the upper left image border. Hazy clouds – especially in the central part of the image – complete the atmospheric feel of the scene. Clouds in the south polar region often contain water ice and their trajectory is partly influenced by the topography of the terrain. During the seasonal cycle, carbon dioxide ice is deposited at the poles in winter, which sublimates in the springtime. Between 12 to 16% of the planet’s atmosphere is deposited in the poles during winter, with the release of gas the following spring boosting the atmospheric pressure and generating strong winds. This ongoing process creates a huge exchange of material between surface and atmosphere throughout the martian year. 📸 @europeanspaceagency/ @germanaerospacecenter/ @fu_berlin; @creativecommons CC BY-SA 3.0 IGO 📸 @NASA/MGS/MOLA Science Team #Mars #RedPlanet #MarsExpress #CreativeCommons