We just published a paper in Geophysical Research Letters (GRL) on the first lidar observations of regular occurrence of mid-latitude thermosphere-ionosphere Na (TINa) layers over Boulder.
https://doi.org/10.1029/2021GL093729
This is the first time that metal layers are regularly seen at these extreme altitudes in the atmosphere. Just 10 years ago, Chu’s team discovered such high-altitude metal layers over McMurdo, Antarctica, but there they occur more irregularly.
In the future, lidars with high detection sensitivity enabled by large-aperture telescope, high-efficiency receiver architecture, and powerful transmitter likely lead to the detection of tenuous TIMt layers globally. These layers provide a natural laboratory for studying the ion-neutral coupling and act as tracers for profiling the neutral wind and temperature in the E to lower F regions.
Congratulations on the new discovery!!!
If you don’t mind me asking, could you explain what TINa is? Thank you for your time!
The permanent (main) layers of metal atoms (75–105 km) have been observed from the ground for nearly a century, but neutral metal layers in the thermosphere were not discovered from ground until Chu, Yu, et al. (2011) reported the first lidar observations of TIFe (thermosphere‐ionosphere Fe) layers from Antarctica. Since then, TIMt (thermosphere‐ionosphere metal) observations have been reported
from high to low latitudes, including TINa (thermosphere‐ionosphere Na). But TIMt layers occur irregularly at high and low latitudes and rarely at midlatitudes. Then in this paper, we reported the first lidar observations of regular occurrence of mid-latitude TINa layers. Hope this explanation can help you understand better.