Mars is Dropping it Low!

Researchers using NASA's Mars Reconnaissance Orbiter have found that temperatures in the Martian atmosphere regularly rise and fall not just once each day, but twice. Temperatures swing by as much as 58 degrees Fahrenheit (32 kelvins) in this odd, twice-a-day pattern, as detected by the orbiter's Mars Climate Sounder instrument.

Global oscillations of wind, temperature and pressure repeating each day or fraction of a day are called atmospheric tides. In contrast to ocean tides, they are driven by variation in heating between day and night. Earth has atmospheric tides, too, but the ones on Earth produce little temperature difference in the lower atmosphere away from the ground. On Mars, which has only about one percent as much atmosphere as Earth, they dominate short-term temperature variations throughout the atmosphere.

"We think of Mars as a cold and dry world with little water, but there is actually more water vapor in the Martian atmosphere than in the upper layers of Earth's atmosphere," maximum a little after midnight," said Armin Kleinboehl of NASA's Jet Propulsion Laboratory in. "Water-ice clouds have been known to form in regions of cold temperatures, but the feedback of these clouds on the Mars temperature structure had not been appreciated. We know now that we will have to consider the cloud structure if we want to understand the Martian atmosphere. This is comparable to scientific studies concerning Earth's atmosphere, where we have to better understand clouds to estimate their influence on climate."

Chemistry group: Melissa Cruz, Dasmany Deniz, and Marlenys Rey