A giant streak structure among the clouds covering planet Venus has been revealed by the observation of the Japanese spacecraft Akatsuki, according to reports from Kobe University.
Thanks to large-scale climate simulations, scientists revealed the origins of the structures.
The discovery was made by scientists led by Project Assistant Professor Hiroki Kashimura (Kobe University, Graduate School of Science) and the findings were published in Nature Communications.
Venus is often called Earth’s twin because of its similar size and gravity, but the weather on Venus is very different from that of Earth.
Venus rotates in the opposite direction to Earth and does so much more slowly (approximately one rotation during 243 Earth days).
Meanwhile, above Venus’ surface a speedy east wind circles the planet in about 4 Earth days, at a speed of 360 km/h, a phenomenon known as atmospheric superrotation.
The Venusian sky is completely covered by thick clouds of sulfuric acid that are located at an average height between 45-70 kilometers, making it difficult to observe the surface of the planet from telescopes and terrestrial orbiters that study Venus.
The temperatures of the surface reach a scorching 460 degrees Celsius, which means that landing a probe on the surface is an extremely difficult mission.
Because of these hostile conditions, there are still many unknowns regarding the atmospheric phenomena of Venus, and what its landscape looks like in detail.
But to help us understand more about Venus, the Japanese spacecraft Akatsuki began orbiting the planet in December 2015.
The Japanese spacecraft carries a number of observational instruments, among them an infrared camera dubbed as “IR2” that measures wavelengths of 2 μm (0.002 mm).
This camera has the ability to capture detailed cloud morphology of the lower cloud levels on Venus, 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, explain experts in the article published by Kobe University.
Before the Akatsuki mission began, the research team developed a program called AFES-Venus that allows calculating simulations of Venus’ atmosphere.
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.
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.
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 high spatial resolution. However, because of the low quality of observational data before Akatsuki, it was hard to prove whether these simulations were accurate reconstructions.