Giant pattern discovered in the clouds of planet Venus

January 10, 2019, Kobe University
Giant pattern discovered in the clouds of planet Venus
Figure 1: (left) the lower clouds of Venus observed with the Akatsuki IR2 camera (after edge-emphasis process). The bright parts show where the cloud cover is thin. You can see the planetary-scale streak structure within the yellow dotted lines. (right) The planetary-scale streak structure reconstructed by AFES-Venus simulations. The bright parts show a strong downflow. Credit: Nature Communications. CC BY 4.0

A Japanese research group has identified a giant streak structure among the clouds covering planet Venus based on observation from the spacecraft Akatsuki. The team also revealed the origins of this structure using large-scale climate simulations. The group was led by Project Assistant Professor Hiroki Kashimura (Kobe University, Graduate School of Science) and these findings were published on January 9 in Nature Communications.

Venus is often called Earth's twin because of their similar size and gravity, but the climate on Venus is very different. Venus rotates in the opposite direction to Earth, and a lot more slowly (about one rotation for 243 Earth days). Meanwhile, about 60 km above Venus' surface a speedy east wind circles the planet in about 4 Earth days (at 360 km/h), a phenomenon known as atmospheric .

The sky of Venus is fully covered by thick of sulfuric acid that are located at a height of 45-70 km, making it hard to observe the planet's surface from Earth-based telescopes and orbiters circling Venus. Surface temperatures reach a scorching 460 degrees Celsius, a harsh environment for any observations by entry probes. Due to these conditions, there are still many unknowns regarding Venus' atmospheric phenomena.

To solve the puzzle of Venus' atmosphere, the Japanese spacecraft Akatsuki began its orbit of Venus in December 2015. One of the observational instruments of Akatsuki is an infrared camera "IR2" that measures wavelengths of 2 μm (0.002 mm). This camera can capture detailed cloud morphology of the lower cloud levels, about 50 km from the surface. Optical and ultraviolet rays are blocked by the upper cloud layers, but thanks to infrared technology, dynamic structures of the lower clouds are gradually being revealed.

Before the Akatsuki mission began, the research team developed a program called AFES-Venus for calculating simulations of Venus' atmosphere. On Earth, atmospheric phenomena on every scale are researched and predicted using , from the daily weather forecast and typhoon reports to anticipated climate change arising from global warming. For Venus, the difficulty of observation makes numerical simulations even more important, but this same issue also makes it hard to confirm the accuracy of the simulations.

Giant pattern discovered in the clouds of planet Venus
Figure 2: The formation mechanism for the planetary-scale streak structure. The giant vortexes caused by Rossby waves (left) are tilted by the high-latitude jet streams and stretch (right). Within the stretched vortexes, the convergence zone of the streak structure is formed, a downflow occurs, and the lower clouds become thin. Venus rotates in a westward direction, so the jet streams also blow west. Credit: Kobe University

AFES-Venus had already succeeded in reproducing superrotational winds and polar temperature structures of the Venus atmosphere. Using the Earth Simulator, a supercomputer system provided by the Japan Agency for Marine-Earth Science and Technology (JAMSTEC), the research team created numerical simulations at a . However, because of the low quality of observational data before Akatsuki, it was hard to prove whether these simulations were accurate reconstructions.

This study compared detailed observational data of the lower cloud levels of Venus taken by Akatsuki's IR2 camera with the high-resolution simulations from the AFES-Venus program. The left part of Figure 1 shows the lower cloud levels of Venus captured by the IR2 camera. Note the almost symmetrical giant streaks across the northern and southern hemispheres. Each streak is hundreds of kilometers wide and stretches diagonally almost 10,000 kilometers across. This pattern was revealed for the first time by the IR2 camera, and the team have named it a planetary-scale streak structure. This scale of streak structure has never been observed on Earth, and could be a phenomenon unique to Venus. Using the AFES-Venus high-resolution simulations, the team reconstructed the pattern (Figure 1 right-hand side). The similarity between this structure and the camera observations prove the accuracy of the AFES-Venus simulations.

Next, through detailed analyses of the AFES-Venus simulation results, the team revealed the origin of this giant streak structure. The key to this structure is a phenomenon closely connected to Earth's everyday weather: polar jet streams. In mid and high latitudes of Earth, a large-scale dynamics of winds (baroclinic instability) forms extratropical cyclones, migratory high-pressure systems, and polar jet streams. The results of the simulations showed the same mechanism at work in the cloud layers of Venus, suggesting that jet streams may be formed at high latitudes. At lower latitudes, an atmospheric wave due to the distribution of large-scale flows and the planetary rotation effect (Rossby wave) generates large vortexes across the equator to latitudes of 60 degrees in both directions (figure 2, left). When jet streams are added to this phenomenon, the vortexes tilt and stretch, and the between the north and south winds forms as a streak. The north-south wind that is pushed out by the convergence zone becomes a strong downward flow, resulting in the planetary-scale streak structure (figure 2, right). The Rossby wave also combines with a large atmospheric fluctuation located over the equator (equatorial Kelvin wave) in the lower cloud levels, preserving the symmetry between hemispheres.

This study revealed the giant streak structure on the planetary scale in the lower cloud levels of Venus, replicated this structure with simulations, and suggested that this streak structure is formed from two types of atmospheric fluctuations (waves), baroclinic instability and jet streams. The successful simulation of the planetary-scale streak structure formed from multiple atmospheric phenomena is evidence for the accuracy of the simulations for individual phenomena calculated in this process.

Until now, studies of Venus' climate have mainly focused on average calculations from east to west. This finding has raised the study of Venus' climate to a new level in which discussion of the detailed three-dimensional structure of Venus is possible. The next step, through collaboration with Akatsuki and AFES-Venus, is to solve the puzzle of the climate of Earth's twin Venus, veiled in the thick cloud of sulfuric acid.

Explore further: Image: Cloudy Venus

More information: Hiroki Kashimura et al. Planetary-scale streak structure reproduced in high-resolution simulations of the Venus atmosphere with a low-stability layer, Nature Communications (2018). DOI: 10.1038/s41467-018-07919-y

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Phyllis Harmonic
4.2 / 5 (10) Jan 10, 2019
So, not caused by magnetism / plasma /electrical whatevers. No surprise there, but you just know there's going to be at least one bafflegabber who'll be calling BS on this finding in favor of their EU gospel.
Whydening Gyre
4.5 / 5 (8) Jan 10, 2019
Lol... YOu KNOW CD won't be able to resist. For him, vortex wind patterns are ALWAYS signs of electrical activity...
cantdrive85
1.9 / 5 (9) Jan 11, 2019
Yep, there is little doubt these are cause by Birkeland currents regardless of the results of their computer games.
Da Schneib
4.4 / 5 (7) Jan 11, 2019
Curiously, no Birkeland currents have been detected in the Earth's jet stream. /s
cantdrive85
2 / 5 (8) Jan 11, 2019
Curiously, no Birkeland currents have been detected in the Earth's jet stream. /s

The moron da schnied decides to add his two cents, obviously not grasping how Birkeland currents work. Back to your hole da schnied.
Phyllis Harmonic
5 / 5 (4) Jan 11, 2019
Lol... YOu KNOW CD won't be able to resist. For him, vortex wind patterns are ALWAYS signs of electrical activity...

CD is right on cue . . . . talk about an easy call! : )
antigoracle
1 / 5 (2) Jan 11, 2019
Curiously, no Birkeland currents have been detected in the Earth's jet stream. /s

There you go again, Da Snot, braying like a jackass and pulling another nugget out of Uranus.
Da Schneib
3.4 / 5 (5) Jan 11, 2019
Still waiting for someone to show Birkeland currents in the jet stream.

Or plasmoids making the rings of Saturn.
prpuk
1 / 5 (1) Jan 12, 2019
"On Earth, atmospheric phenomena on every scale are researched and predicted using numerical simulations, from the daily weather forecast and typhoon reports to anticipated climate change arising from global warming"

Many climate behaviors on Earth are still not understood nor are they predictable, such as ENSO and QBO. The clue in comparing Venus and Earth is in the fact that Venus has no moons to perturb it's flow. Contrast that to Saturn and Jupiter where the moons have a significant role in the behavior of the rings and jet streams.
cantdrive85
2.3 / 5 (6) Jan 12, 2019
The Birkeland currents are entering the poles, the planet is sitting in the barrel of a series of counter-rotating concentric cylindrical tubes (just as figure 2 shows above). The "jet stream" is one of these cylinders connecting to the planet's atmosphere. The rotation of the cylinder is the jet stream, this mechanism explains the super-rotation of Venus' atmosphere as well. The same cylindrical Birkeland current and the energy they carry is what drives weather and climate on all planets.
Jupiter's Birkeland currents with counter-rotating cylinders easily visible here;
https://youtu.be/Z69NfO6iY4c
Gorgar
1 / 5 (2) Jan 12, 2019
Vortices are caused by magnetic precession.
jonesdave
3.4 / 5 (5) Jan 12, 2019
The Birkeland currents are entering the poles, the planet is sitting in the barrel of a series of counter-rotating concentric cylindrical tubes (just as figure 2 shows above). The "jet stream" is one of these cylinders connecting to the planet's atmosphere. The rotation of the cylinder is the jet stream, this mechanism explains the super-rotation of Venus' atmosphere as well. The same cylindrical Birkeland current and the energy they carry is what drives weather and climate on all planets.
Jupiter's Birkeland currents with counter-rotating cylinders easily visible here;
https://youtu.be/Z69NfO6iY4c


Lol. Cranks, eh?
jonesdave
3.4 / 5 (5) Jan 12, 2019
Just a little clue for the hard of thinking - Birkeland currents in the Earth's polar regions are due to the interaction of the solar wind with the Earth's magnetic field. There is plenty in the literature about it.
Venus doesn't have an intrinsic magnetic field. The interaction with the solar wind is more like that of a comet. So, where are the Birkeland currents popping into existence from?
cantdrive85
2.3 / 5 (3) Jan 13, 2019
Birkeland currents in the Earth's polar regions are due to the interaction of the solar wind with the Earth's magnetic field

Backwards as usual, the magnetic field is duev to the Birkeland current. The "dynamo" that creates Earth's magnetic field is these Birkeland that are driven by the Sun. And yes, Venus interaction is different due to the different conditions.
Da Schneib
3.7 / 5 (3) Jan 13, 2019
And actually, that's technically wrong. Birkeland currents aren't "entering the poles."
Da Schneib
3.7 / 5 (3) Jan 13, 2019
And OBTW, the weather patterns on Venus do not coincide with a magnetic field. Several nations have orbited satellites around Venus and found none. Yet, here this effect is, with no forces but gravity and EM to drive it. No EM detected. What's your conclusion?
Da Schneib
5 / 5 (1) Jan 13, 2019
The most interesting thing about the differences between Venus and Earth is that one is orbitally locked and the other is not, and one doesn't have a magnetic field and the other does. To my mind this seems to be the reason for the differences between them. It would be facile to attribute these differences to the difference in irradiance, but I don't think that's the cause given the vast differences in their magnetospheres.
cantdrive85
3 / 5 (2) Jan 13, 2019
So, where are the Birkeland currents popping into existence from?


Birkeland currents aren't "entering the poles."


Remember, flux rope is plasma ignoramus terminology for Birkeland current.
https://www.space...pes.html
FredJose
1 / 5 (1) Jan 15, 2019
Heated arguments about EU and other speculations.

In the meantime, Venus represents a perfect contradiction of the Nebular hypothesis of planet formation. The fact that it is spinning in the opposite direction to earth and the other planets in the solar system is a dead give away that that nebulous speculation is just a religious stronghold.

Each planet has characteristics that belie the nebulous story. Those characteristics make for fascinating reading.
Whydening Gyre
5 / 5 (1) Jan 15, 2019
Heated arguments about EU and other speculations.

In the meantime, Venus represents a perfect contradiction of the Nebular hypothesis of planet formation. The fact that it is spinning in the opposite direction to earth and the other planets in the solar system is a dead give away that that nebulous speculation is just a religious stronghold.

Why is it a dead giveaway?
Each planet has characteristics that belie the nebulous story. Those characteristics make for fascinating reading.

The only thing nebulous here, is your comment...

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