Using Curiosity’s navigation camera, Moores and Kloos recorded eight-frame movies of this wispy cloud belt for two martian years. They’ve used two angles to capture the clouds: one pointed directly up, to see wind direction and speed, and another that keeps the rover’s horizon in the frame, allowing a view into the clouds’ depth. The captured clouds are so thin as to be invisible without painstaking computer enhancement, Kloos said in his presentation Tuesday.
...Given the limited water vapor, solar energy, and atmosphere, the martian clouds lack the variety of shapes seen on Earth. But during one day of cloud gazing—Curiosity’s 1302th martian day, to be precise—the team got lucky and saw something unusual. That day, when Curiosity looked to the horizon, it saw a sequence of straight, parallel rows of clouds flowing in the same direction: the first ground-based view of a gravity wave cloud. Similar to the waves that follow a pebble tossed into a pond, gravity waves are created when some unknown feature of the martian landscape causes a ripple in the atmosphere that is then seen in clouds. Such waves are common at the edge of the martian ice caps, but thought to be less frequent over its equator.
Sunday, March 26, 2017
Gravity Wave Clouds Imaged By Mars Rover