Iron Boltzmann lidar temperature and density observations from Arecibo - An initial comparison with other techniques

Abstract

We introduce the first measurements of upper atmospheric temperature made from the Arecibo Observatory using the iron Boltzmann lidar technique. We use a single laser transmitter that can flip between two emissions every other pulse, which is suitable to observe the two iron transitions within the same region of space. Comparisons are made with airglow measurements and the MSIS-90 model to estimate temperature, and with incoherent scatter radar observations to associate the structure of electron concentration with enhancements observed in the concentration of neutral iron. We find good agreement between lidar and airglow derived temperatures near the mesopause, while the model tends to underestimate the thermal depth of the mesopause at Arecibo compared with observations. In addition, simultaneous temperatures measured via lidar and airglow may help to clarify the heights where the airglow emissions occur.