Nighttime may be snow-time on Mars.
Low evening temperatures could cool clouds and trigger turbulent winds that fuel fast-falling snowstorms on the Red Planet, new simulations suggest. This process, reported August 21 in Nature Geoscience, may account for surprising observations of snowfall by one of NASA’s Martian landers.
“Clouds and snowfall have emerged in recent years as central players in the water cycle and climate of Mars,” says Paul Hayne, a geophysicist at NASA’s Jet Propulsion Laboratory in Pasadena, Calif., who wasn’t involved in the research. The new study was able to create the rapid snowfall by simulating climate on a much finer scale than previous simulations. That shows the need for local-scale weather data to understand the most fundamental aspects of Mars’ climate, Hayne says.
Satellite observations show that snow made of both water and carbon dioxide cover the Martian poles, and, in 2008, NASA’s Phoenix lander detected streaks of snow falling below a nighttime water-ice cloud (SN Online: 6/20/08). This was the first time scientists had seen evidence of snowfall on Mars.