The researchers found that the principles that govern air turbulence in the troposphere also apply in the thermosphere. The study, published in the journal Geophysical Research Letters, shows that turbulence in the thermosphere obeys the same physical laws as wind in the lower atmosphere. The study also found that wind in the thermosphere is predominantly cyclonic, meaning it rotates counterclockwise in the Northern Hemisphere and clockwise in the Southern Hemisphere.

The results provide a new unifying principle for Earth’s diverse ecological systems and could potentially improve future predictions of both terrestrial and space weather.

Night clouds in Kühlungsborn, Germany. Their delicate and complex structure and motion indicate the existence of atmospheric gravity waves and turbulence. Copyright: Gerd Baumgarten/The Institute for Atmospheric Physics is named after Leibniz

Sooner or later we start checking the latest weather forecast, and while that gives us a good idea of ​​our daily atmospheric conditions, the research that goes into how air moves around the Earth is dizzyingly complex.

“At a fundamental level, we study the interaction of kinetic energy in the atmosphere at different sizes and scales, mainly in the form of wind and turbulence. Over the decades, a huge amount of data has given us insight into how this energy flows and disperses, affecting weather in the troposphere, the lowest layer of the atmosphere,” explains Professor Huixing Liu from the School of Natural Sciences at Kyushu University, who led the study. “My research focuses on motions in the upper atmosphere, particularly in the thermosphere, where we study the dynamics and related laws governing energy flows in this region.”

Research collaboration and results

The thermosphere is the part of the atmosphere located approximately 80-550 km above sea level and is often referred to as the gateway to space. It is a critical region for space activities and is home to the International Space Station and most satellites. Auroras are also formed here.

Liu collaborated with meteorology researcher Dr. Facundo L. Poblet of the Institute of Atmospheric Physics Leibniz of the University of Rostock, whose work focuses on dynamics and turbulence in the lower atmosphere below 100 km altitude.

“My research is in space physics, and I wanted to see if we could apply his meteorological methods to my own field of research,” Liu explains.

The team analyzed thermospheric wind data from two satellites: the Challenging Minisatellite Payload (CHAMP) and the Gravity Field and Steady-State Ocean Circulation Explorer (GOCE). Using this data, the team calculated the third-order wind structure function, a statistical quantity that provides information about the underlying turbulence. Surprisingly, they found that the thermosphere exhibits a scaling law similar to the lower atmosphere.

“This means that both the thermosphere and the troposphere – despite the radically different composition and dynamics of the atmosphere – are subject to the same physical laws. The way energy flows and dissipates in these two regions is very similar,” Liu continues.

Despite significant progress in understanding the thermosphere, the complex interaction of turbulence and waves at different scales remains largely elusive, and the team is pleased that their results shed new light on this little-studied aspect of near-space dynamics.

“As with atmospheric weather forecasting, understanding the distribution of energy in the thermosphere is vital to advancing our understanding of cosmic dynamics,” Liu concludes. “We hope these findings can be used to improve space weather forecasting and ensure the continued functionality and safety of satellite technologies essential to daily life.”