Study of a lidar for measurement of thermospheric He I 1083 nm for Lorentzian profile

Using the lidar backscatter cross-section and the normalized Lorentzian profile, we investigate the backscatter cross-section and the returned signal of He I 1083 nm for the Lorentzian profile theoretically. Taking the average temperature and pressure, we find that the backscattering cross-section for Lorentzian profile is larger than that for Gaussian profile near the line center, while is smaller than that for Gaussian profile far away from the line center. Through simulation, we find that the returned signal is strong enough for measurement of thermospheric metastable helium. This investigation is significant in the thermospheric metastable helium by lidar.