First 3D view of Jupiter’s atmosphere

The new data from NASA Juno Probe orbiting around Jupiter provides a more complete picture of its atmosphere, offering clues to the unseen processes taking place beneath its clouds. The results highlight the inner workings of the cloud belts and areas surrounding Jupiter, as well as its polar cyclones and its well-known Great Red Spot.

An international group of researchers this week publishes several articles about these findings in journals. Science it’s him Journal of Geophysical Research: Planets, which are added to others that have recently appeared in Geophysical Research Letters, and they also explained them in a presentation connected. “Each article sheds light on different aspects of the planet’s atmospheric processes,” he highlights. lori enamel, director of NASA’s Division of Planetary Sciences.

We’re starting to put all the pieces together to get our first real understanding of how Jupiter’s beautiful and violent atmosphere works in 3D.

Scott Bolton (Southwest Research Institute)

Juno entered Jupiter’s orbit in 2016. During each of the 37 passes As the spacecraft has operated on the planet thus far, its instruments have looked down from its turbulent cloud cover.

“Juno has previously surprised us with indications that phenomena in Jupiter’s atmosphere were deeper than expected,” he explains. Scott Bolton, principal investigator of this mission who works at the Southwest Research Institute in San Antonio (USA) and lead author of an article in Science about the depth of Jupiter’s vortices. “Now, we’re starting to put all these individual pieces together and get our first real understanding of how Jupiter’s beautiful and violent atmosphere works in 3D.”

O microwave radiometer (MWR) Juno allowed his team to peek below the top of Jupiter’s clouds and probe the structure of its many vortex storms. The most famous is the iconic anticyclone known as big red spot, a colossal storm 16,000 kilometers wide. Wider than Earth, this crimson vortex has intrigued scientists since its discovery nearly two centuries ago.

This illustration combines an image of Jupiter from Juno’s JunoCam instrument with one of Earth to represent the size and depth of Jupiter’s Great Red Spot. / JunoCam Image data: NASA / JPL-Caltech / SwRI / MSSS; JunoCam Image Processing by Kevin M. Gill (CC BY); Earth Image: NASA

The new results show that cyclones they are warmer at the top, with lower atmospheric densities, while they are cooler at the bottom, with higher densities. However, the anticyclones, which rotate in the opposite direction, are cooler at the top and warmer at the bottom.

The findings also indicate that these storms are much larger or deeper than expected, with some extending 100 kilometers below the cloud tops and others, including the Great Red Spot, extending more than 350 kilometers. This surprising finding shows that the vortices cover regions beyond those where water condenses and clouds form, below the depth at which sunlight warms the atmosphere.

The height and size of the Great Red Spot mean that the concentration of atmospheric mass within the storm can be detected by instruments that study Jupiter’s gravitational field. Two close-by flights over it offered the opportunity to research the gravitational signature of the storm and complement the MWR results in depth.

With Juno traveling low above Jupiter’s cloud cover at about 209,000 km/h, scientists were able to measure velocity changes as small as 0.01 millimeters per second using an antenna tracking the NASA Deep Space Network on Earth, at a distance of more than 650 million kilometers. This allowed the team limit the depth of the Great Red Spot to about 500 kilometers below the top of the clouds.

“The precision needed to obtain the gravity of the Great Red Spot during the July 2019 flyover is staggering,” he says. Marzia Paris, a Juno scientist at NASA’s Jet Propulsion Laboratory in Southern California and lead author of another article in Science. “Being able to complement the MWR finding with depth information; we are confident that future gravitational experiments on Jupiter will yield equally intriguing results. “

Belts and zones

In addition to cyclones and anticyclones, Jupiter is known for its characteristic belts and zones: white and reddish bands of clouds that involve the planet. Strong east-west winds moving in opposite directions separate the tracks. Juno had already discovered that these winds, or jet streams, they reached depths of approximately 3,200 kilometers. Researchers are still trying to solve the mystery of how these currents form. The data collected by the MWR offer a possible clue: the ammonia gas in the atmosphere rises and falls substantially in line with the observed jets.

“By following ammonia, we find circulating cells in the northern and southern hemispheres that are similar in nature to the so-called Ferrel Cells, which control much of our climate here on Earth,” he says. Keren Duer, researcher at the Weizmann Institute of Science in Israel and lead author of another article in Geophysical survey charts in these structures. “While Earth has one Ferrel cell per hemisphere, Jupiter has eight, each at least 30 times larger.”

The MWR radiometer data also show that the belts and zones transition about 40 miles below Jupiter’s water clouds. At shallow depths, the planet’s belts are brighter in microwave light than neighboring areas. But at deeper levels, below the water clouds, the opposite occurs, revealing a resemblance to our oceans.

“We call this level joviclina by analogy with the transition layer observed in Earth’s oceans, known as thermocline, where the sea water changes abruptly from relatively warm to relatively cold”, he explains. Leigh Fletcher, a scientist at the University of Leicester (UK) and lead author of the article in Journal of Geophysical Research: Planets where Juno’s microwave observations of the Jupiter belts and temperate zones stand out.

Stable polar cyclones

Juno also observed polygonal arrays of giant cyclonic storms at both of Jupiter’s poles: eight arranged in an octagonal pattern in the north and five in a pentagonal pattern in the south. Now, five years later, the data from the Jovian Infrared Auroral Mapper (JIRAM) of the ship to determine that these atmospheric phenomena are extremely resistant, remaining in the same place.

“Jupiter’s cyclones affect each other in its movement, causing it to oscillate around an equilibrium position,” he says. alessandro wall, Juno’s co-investigator at the National Institute of Astrophysics in Rome and lead author of another article from Geophysical survey charts in the oscillations and stability of Jupiter’s polar cyclones. “The behavior of these slow oscillations suggests that they have deep roots,” he adds.

JIRAM data also indicate that, like hurricanes on Earth, these cyclones try to move towards the poles but are pushed back by centrally located cyclones. This balance explains where the cyclones reside and the different numbers that appear at each pole.