Himawari meteorological satellites measure temperature changes on Venus

Date:
Sun, 06 Jul 2025 20:48:36 +0000

Description:
On Oct. 7, 2014, and Nov. 2, 2016, the Japanese Himawari 8 and Himawari 9 The post Himawari meteorological satellites measure temperature changes on Venus appeared first on NASASpaceFlight.com .

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On Oct. 7, 2014, and Nov. 2, 2016, the Japanese Himawari 8 and Himawari 9 Earth observation satellites were launched, respectively. Operated by the Japanese Meteorological Agency (JMA), the two satellites are primarily used
to monitor typhoons, rainstorms, and other weather phenomena in the vicinity of Japan, East Asia, and the western Pacific. However, in a new study led by
a team from the University of Tokyo, the two weather satellites were used to observe temperature changes on Venus not Earth.

Using infrared imaging data collected by the two satellites over a 10-year period from 2015 to 2025, the team estimated brightness temperatures on day-to-year scales. The results revealed temporal changes in Venus cloud-top temperatures, as well as previously unseen patterns in the planets
atmospheric temperature structure.



Specifically, the team, led by Gaku Nishiyama, utilized the satellites multispectral Advanced Himawari Imager (AHI) instrument to observe Venus, which is occasionally seen near Earths rim from the satellites orbit. While scientists have had access to Venusian meteorological data for decades thanks to NASAs Magellan mission and several spacecraft flybys, the use of the Himawari satellites to observe Venus highlights how meteorological satellites in Earth orbit can be used to support missions dedicated to exploring Venus.

Similar in size to Earth, Venus is often referred to as Earths twin. However, the two planets are very different, with Venus surface pressure, temperature, and atmospheric composition and structure varying wildly from Earths. In particular, Venus atmosphere is approximately 90 times denser than Earths and is composed of 96.5% carbon dioxide trapping heat and making Venus the hottest planet in the solar system. Launch of Himawari-8 in October 2014. (Credit: JMA)

Measuring and analyzing Venus temperature, specifically in its cloud tops, is vital to understanding Venusian atmospheric dynamics, structure, and phenomena, like thermal tides and planetary-scale waves. However, collecting data that highlights these phenomena and atmospheric characteristics is difficult when it comes to Venus. See Also Japanese Launchers Section Space Science Section Click here to Join L2

The atmosphere of Venus has been known to exhibit year-scale variations in reflectance and wind speed; however, no planetary mission has succeeded in continuous observation for longer than 10 years due to their mission lifetimes. Ground-based observations can also contribute to long-term monitoring, but their observations generally have limitations due to the Earths atmosphere and sunlight during the daytime, explained Nishiyama.

With much longer mission lifetimes than deep-space spacecraft, meteorological spacecraft could become a viable option for long-term observations of
planets, moons, and more. Himawari-8 celebrated its 10-year launch
anniversary last year, and Himawari-9 is set to celebrate its 10-year launch anniversary next year. Both satellites are expected to continue operating until 2029.

Furthermore, multispectral imagers that enable multiband infrared observations, similar to the AHIs on the Himawari satellites, are not often available on deep-space planetary missions. These types of imagers are
crucial for collecting temperature data from different regions of a planets atmosphere while also providing low-noise and frequent observations.
Schematic showing the design of the Himawari-8 and -9 satellites. (Credit: JMA)

Nishiyama et al. were aware of the lack of AHI-like imagers on missions to Venus, as well as the limited number of Venus missions planned for the next decade, which prompted them to utilize the Himawari satellites AHI to investigate the planet.

We believe this method will provide precious data for Venus science because there might not be any other spacecraft orbiting around Venus until the next planetary missions around 2030, said Nishiyama.

To achieve their results, the team first reviewed AHI datasets for images in which Venus was visible. In total, the team identified 437 images in which Venus could be seen, storing them within a data archive. Then, by accounting for background noise and Venus apparent size from Earth, the team was able to identify and track changes in cloud-top temperatures and brightness. Image taken by Himawari-8 showing Earth and Venus. (Credit: Nishiyama et al.)

These variations in temperature and brightness were further analyzed on day and year scales to search for thermal tides and planetary-scale waves.
Thermal tides are repeated variations in pressure, temperature, and wind patterns due to the natural heating and cooling of a planetary body by the Sun. Planetary-scale waves are large-scale atmospheric waves caused by the rotation of a planet that influence weather patterns and conditions.

The data confirmed the presence of both thermal tides and planetary-scale waves, and variations in the amplitudes of both phenomena were observed, with the amplitude of planetary-scale waves decreasing with altitude. The exact physics and processes behind the phenomena could not be definitively determined due to the limited temporal resolution of the AHIs, but the team believes the variations in thermal tide could be due to the change in Venus atmospheric structure that occurs every 10 years.

Nishiyama et al. also used the Himawari data to highlight calibration discrepancies in data collected by previous planetary science missions to Venus. Data collected by Himawari-8 and Himawari-9s AHI showing temperature variation at Venus over a 10-year period. (Credit: Nishiyama et al.)

Being able to collect long-term data on planetary characteristics using Earth observation satellites instead of ground-based telescopes, whose capabilities are often limited due to Earths atmosphere, is an exciting possibility. Nishiyama is already looking to expand this capability to planets other than Venus.

I think that our novel approach in this study successfully opened a new
avenue for long-term and multiband monitoring of solar system bodies. This includes the moon and Mercury, which I also study at present. Their infrared spectra contain various information on physical and compositional properties of their surface, which are hints at how these rocky bodies have evolved
until the present, Nishiyama said.

We hope this study will enable us to assess physical and compositional properties, as well as atmospheric dynamics, and contribute to our further understanding of planetary evolution in general.

Nishiyama et al.s study was published in SpringerOpen on June 30.

(Lead image: Render showing the fully deployed Himawari-8 satellite. Credit: JMA)



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Link to news story:
https://www.nasaspaceflight.com/2025/07/himawari-venus/


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