NASA’s Jet Propulsion Laboratory will provide daily weather reports for Mars, thanks to the Red Planet’s newest robotic resident, InSight, mission scientists announced on Thursday. “The InSight lander is close to the Martian equator—just north of the equator—so it is experiencing Martian winter,” said Don Banfield, the mission’s lead for the lander’s Auxiliary Payload Subsystem (APSS).
APSS is a suite of meteorological sensors on the lander’s deck that also helps with quake detection. “For our mission, APSS will help us filter out noise in our data and know when we’re seeing a Mars quake and when we aren’t,” said Banfield, a principal research scientist at Cornell University in the US.
“But by operating continuously, we’ll also see a more detailed view of the weather than most surface missions, which usually collect data for just a few hours at a time,” Banfield said in a statement. Currently, Mars’ northern hemisphere sits in winter—the stormy season, researchers said.
“Since the lander is close to the equator, I did not think we would see any evidence of the storms that are 60-degrees north latitude, but we are already seeing evidence of the high and low pressure-signal waves that create weather on Mars,” Banfield said.
“We can see those waves all the way down near the equator, as the waves are big enough that they have a signature. That was a surprise,” he said in a statement. The pressure signals oscillate every 2.5 sols (the name for days on Mars), and the waves are easier to predict as opposed to how pressure waves behave on Earth. One sol is about 24 hours, 39 minutes long.
“High and low pressure is indicative of the weather systems,” Banfield said. “Compared to Mars, Earth is pretty chaotic. Mars has a nearly perfect, smooth sinusoidal (up and down) waves—it is a very regular seesaw guided by a metronome on Mars. On Earth, the pressure is guided by a hyperactive child,” he said.
Mission scientists said the coldest temperatures—as cold as minus 59 degrees Celsius—occur at around 5 am local time. The warmest temperatures have been minus five degrees Celsius. When the sun heats up the Martian surface, scientists have observed strong convective overturning.
“Think of a pot of water boiling—the water is overturning vigorously. That happens on Mars, too,” Banfield said. “The atmosphere near the ground bubbles up like a buoyant plume of air. It happens on Earth, too, but you don’t feel it as much. On Mars it happens with a lot more vigour,” he said.
In another surprise, mission scientists are observing many “dust devils”—those ghostly, low-pressure, tornado-like whirls of Martian soil. “They spin at nearly 96 kilometres per hour. They do shake the lander, and we have seen a lot of that. They even tilt the ground, because we have such a sensitive seismometer,” Banfield said.
“On Earth, the desert’s dust devils would be likely 15 metres across and almost a kilometer tall. On Mars, they can be five to 10 kilometers tall. Big ones are 100 metres or more in diameter,” he said. The InSight craft landed on Mars in late November and is preparing to monitor the geologic interior of the planet.