Atmospheric sodium has been observed over Urbana (40°10′N, 88°10′W) using a monostatic lidar tuned to 589.0 nm. The photocount data are processed using digital smoothing filters to obtain continuous estimates of the sodium density versus altitude. The filter cutoff frequency is related to the height resolution and accuracy of the estimated profile. Wavelike structures in the sodium layer have been observed with typical wavelengths of 3-15 km and phase velocities of 1-3 m s-1. The layer is characterized by a sharp falloff on the bottomside and often an undulatory motion of the bottomside of the layer accompanies the wave motion. The topside gradient of the layer is frequently observed to decrease through the night.
ASJC Scopus subject areas
- Environmental Science(all)
- Atmospheric Science
- Earth and Planetary Sciences(all)