Planetary Scale Streak Structures
Using the Earth Simulator, a supercomputer system provided by the Japan Agency for Marine-Earth Science and Technology (JAMSTEC), a research team created numerical simulations at a high spatial resolution. Tehy found massive symmetrical giant streaks across the northern and Southern Hemispheres stretching 10,000 km diagonally across Venus and is hundreds of kilometers wide. It’s been named A PLANETARY SCALE STREAK STRUCTURE.
Observations from the Japanese spacecraft Akatsuki show massive patterns in cloud structures in Venus’ atmosphere.
The team also revealed the origins of this structure using large-scale climate simulations. The group was led by Project Assistant Professor Hiroki Kashimura at Kobe University.
Venus is about the same size and has about the same gravity as Earth however it rotates much slower than earth ph and in the opposite direction. One Venus rotation takes about 243 Earth days.
But Venus’ atmosphere, which is about 60km above its surface rotates in only 4 earth days moving at 360 km/s this is known as atmospheric super rotation.
It’s very difficult for earth based telescopes and even orbiters of Venus to make observations of its surface because of the thick sulfuric acid clouds between 45-70km above the surface. Oh and the temps are around 460 degree C (860F).
This Japanese space craft was able to reveal lower cloud structures using the spacecrafts infrared camera IR2 because any ultraviolet or optical waves are blocked by the upper cloud layers.
Similar to how weather people and scientists calculate and even predict weather conditions here on earth, the Japanese program called AFES-Venus was developed to do the same thing.
By creating simulations the team was able to reproduce super rotational winds and polar temperature structures in Venus’ atmosphere.
Thanks to the sharper observation data from Akatsuki scientists were able to confirm early predictions of the weather on Venus that was made a while back using the supercomputer.
Being able to make a direct comparison from actual collected data to simulations made by the Earth Simulator way back when shows the accuracy of the simulator. Maybe this can be applicable to many other atmospheric structures out there!! Certainly actual data is best. But hey gotta start with simulations first most of the time!
These gatherings suggest that the giant streak structures formed from two types of atmospheric fluctuations (waves), baroclinic instability and jet streams.
Both of which also occur here on Earth.
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.
And when jet streams are added on vortexes tilt and stretch, and the convergence zone 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.
All this being said, Venus seems to be more similar to Earth as the years go on and more research is done. It’s an exciting time for science right now, I can’t wait till we start applying these findings to other things and start learning how to use Earth-technology for other planets too!