Mars's radiant energy budget profile offers clues to its climate dynamics

Research by scientists at the University of Houston is changing our understanding of climate and weather on Mars and providing critical insights into Earth's atmospheric processes as well.

The study generated the first-ever meridional profile of Mars's radiant energy budget, or REB, which represents the balance or imbalance between absorbed solar energy and emitted thermal energy across the latitudes. On a global scale, an energy surplus leads to global warming, while a deficit results in global cooling. Furthermore, the meridional profile of Mars's REB fundamentally influences weather and climate patterns on the red planet.

The research team was led by Larry Guan, a graduate student in the Department of Physics at UH's College of Natural Sciences and Mathematics, under the guidance of his advisors, Professor Liming Li from the Department of Physics and Professor Xun Jiang from the Department of Earth and Atmospheric Sciences and several planetary scientists.

The findings are in a new paper just published in AGU Advances.

"The work in establishing Mars's first meridional radiant energy budget profile is noteworthy," Guan said. "Understanding Earth's large-scale climate and atmospheric circulation relies heavily on REB profiles, so having one for Mars allows critical climatological comparisons and lays the groundwork for Martian meteorology."

The profile, based on long-term observations from orbiting spacecraft, offers a detailed comparison of Mars's REB to that of Earth, uncovering striking differences in the way each planet receives and radiates energy. While Earth exhibits an energy surplus in the tropics and a deficit in the polar regions, Mars displays the opposite configuration.

"On Earth, the tropical energy surplus drives warming and upward atmospheric motion, while the polar energy deficit causes cooling and downward atmospheric motion," Jiang explained. "These atmospheric motions significantly influence weather and climate on our home planet. However, on Mars, we observe a polar energy surplus and a tropical energy deficit."

That surplus, Guan says, is especially pronounced in Mars's southern hemisphere during spring, playing a critical role in driving the planet's atmospheric circulation and triggering global dust storms, the most prominent feature of Martian weather. These massive storms, which can envelop the entire planet, significantly alter the distribution of energy, providing a dynamic element that affects Mars's weather patterns and climate.

"The interaction between dust storms and the REB, as well as with polar ice dynamics, brings to light the complex feedback processes that likely shape Martian weather patterns and long-term climate stability," Guan said.