We just published a new paper in Geophysical Research Letters (GRL) on the first-ever simultaneous lidar observations of iron (Fe) and sodium (Na) metal layers in the Antarctic thermosphere and ionosphere system.
https://doi.org/10.1029/2020GL090181
Interplanetary dust particles, also called cosmic dust, have a widespread impact on Earth. They introduce metal atoms and ions into Earth’s upper atmosphere. These metal constituents provide a natural laboratory for exploring upper atmosphere chemistry, dynamics, and energetics. Permanent layers of metal Fe (iron) and Na (sodium), which distribute between 75 and 105 km, have been observed from the ground for nearly a century. However, neutral metals above this region had not been discovered until 2011 when a lidar (laser radar) detected thermospheric Fe (TIFe) layers extending to 155 km. The measurements were made from the Arrival Heights Observatory near McMurdo, Antarctica. After years of efforts in developing sophisticated lidar systems and deploying them to Antarctica, the first simultaneous, common-volume lidar observations of meteoric Fe and Na layers in the thermosphere-ionosphere region (TIFe and TINa) were finally achieved in May 2018. The lidar observations reveal striking and unexpected differences between these two metal layers. Furthermore, the thermospheric Fe layers are highly correlated with auroral activity and ionospheric plasma density, but the thermospheric Na layers exhibit a dynamic background. We make the first report of these observations and explore the possible causes.
It’s so fascinating to learn that our atmosphere has permanent layers of Fe and Na. Furthermore, it’s even more interesting to learn that it extends father than the previous area of 75 to 105km! Congratulations on the discovery!