Researchers Find Important Details About Thermal Tides and Planetary Waves on Venus Through a Unique Method
Scientists have discovered a new method to monitor planets, which is weather satellites, and it has already supplied them with a decade's worth of data about the "Morning Star" (Venus), according to Science Daily. The images captured by these satellites have turned out to be a gold mine for astronomers. They have been able to figure out many phenomena functioning on the planet, as well as rectify data brought forth by other missions. The pair of satellites involved in this endeavor is set to go on for four more years, which could lead to more valuable insights. The data brought by these satellites has been discussed in detail in the Earth, Planets and Space journal.
Himawari-8 and -9 Satellites
The weather satellites, the subject of this study, are Japan's Himawari-8 and -9 satellites. They were launched in 2014 and 2016, respectively. Initially, they built these satellites to help astronomers monitor atmospheric phenomena on Earth with the help of equipment called multispectral Advanced Himawari Imagers (AHIs). The study's lead author, Gaku Nishiyama, suggested that the satellites could also be used to get observations on Venus' cloud tops. The satellites have been monitoring Venus along with Earth for a long time due to their positioning near the Earth's rim. The satellites must have images of the Morning Star's cloud tops, and he and his team decided to take a look at them.
Insights Gathered from the Satellites
The team collected a decade's worth of Venus' images from the satellites. They stitched together 437 images, which focused on the Morning Star's cloud tops and observed phenomena like daily thermal tides and shifting planetary waves. These two facets were specifically chosen because, for a long time, they have been a mystery for astronomers.
Researchers were surprised to spot unknown temperature patterns in the infrared images, according to Universe Today. There were multiple infrared bands, like Near-Infrared, Mid-Infrared, and Far-Infrared, in the cloud tops. It implied that there were distinct temperatures in different regions. These variations were detected by mapping the temporal dynamics of Venus' atmosphere on the composite of images, and then comparing them with previous insights available about these phenomena. These changes were then analyzed over daily and yearly periods to understand how thermal tides and planetary waves behave on Venus.
The findings confirmed that thermal tides as well as planetary waves change in terms of amplitude over time. The strength of both phenomena was proportional to their height. The more altitude they had, the stronger they were. The lower they went, the weaker they became. Researchers also found links between the strength of thermal tides and changes in Venus' atmosphere that happened every decade. The processes behind these variations remain a secret, as the resolution of AHIs is not sharp enough to capture that. These findings are crucial in noticing and rectifying certain discrepancies in the data about Venus from previous missions.
Better Option Than Other Alternatives
The team believes that satellite is a better option for observation than missions due to their longevity. These two satellites can track Venus for around two decades, while a mission cannot give more than 10 years in this pursuit. This feature is essential to consider, as Venus' atmosphere changes every year. Hence, the method that provides more continuous data is much preferable, which is the weather satellites. Ground-based satellites face a huge barrier in the form of Earth's atmosphere, which could hamper their readings. The weather satellites have no such thing to worry about.