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In a paper published in Geophysical Research Letters, researchers have discovered that turbulence in the thermosphere follows the same physical laws as wind in the lower atmosphere. Additionally, wind in the thermosphere rotates cyclonically-counterclockwise in the Northern Hemisphere and clockwise in the Southern Hemisphere.
These findings reveal a new principle for Earth's environmental by Riko Seibo
Tokyo, Japan (SPX) Jun 09, 2024
In a paper published in Geophysical Research Letters, researchers have discovered that turbulence in the thermosphere follows the same physical laws as wind in the lower atmosphere. Additionally, wind in the thermosphere rotates cyclonically-counterclockwise in the Northern Hemisphere and clockwise in the Southern Hemisphere.
These findings reveal a new principle for Earth's environmental systems and could improve forecasting of both earth and space weather.
"At the fundamental level, we study the interplay of kinetic energy in the atmosphere at different sizes and scales, that energy is mostly in the form of wind and turbulence. Over the decades, a massive amount of data has given us insight into how this energy flows and dissipates to affect the weather in the troposphere, the lowest layer of the atmosphere," explains Professor Huixin Liu of Kyushu University's Faculty of Science, who led the study. "My research focuses on the movements in the upper atmosphere, specifically the thermosphere, where we explore the corresponding laws governing the dynamics and energy flow in the region."
The thermosphere, located roughly 80-550 km above sea level, is a critical region for space operations, housing the International Space Station and most satellites. It is also where auroras form.
Liu collaborated with meteorology researcher Dr. Facundo L. Poblet of Leibniz Institute of Atmospheric Physics at the University of Rostock, whose work focuses on dynamics and turbulence in the lower atmosphere below 100 km.
"My research is in space physics, and I wanted to see if we could apply his meteorological methods to my research domain," explains Liu.
The team analyzed thermosphere wind data from two satellites, the Challenging Minisatellite Payload (CHAMP) and the Gravity Field and Steady State Ocean Circulation Explorer (GOCE). They calculated the third-order structure function of the wind, a statistical measure of turbulence. To their surprise, they found that the thermosphere exhibits a similar scaling law to the lower atmosphere.
"This means that both the thermosphere and the troposphere-despite having drastically different atmospheric compositions and dynamics-follow the same physical laws. How turbulence moves, forms, and dissipates in these two regions are very similar," continues Liu.
Despite advances in understanding the thermosphere, the intricate interplay of turbulence has remained largely elusive. The team is pleased that their findings shed light on this aspect of near-space dynamics.
"Similar to atmospheric weather forecasting, comprehending the energy distributions in the thermosphere is vital to advance our understanding of space dynamics," concludes Liu. "We hope these findings can be used to improve space weather forecasting and ensure the continued functionality and safety of satellite-based technologies essential to everyday life."
Research Report:Third-order Structure Functions of Zonal Winds in the Thermosphere using CHAMP and GOCE Observations
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