Double-Receiver-Based Pure Rotational Raman LiDAR for Measuring Atmospheric Temperature at Altitudes Between Near Ground and Up To 35 km

Abstract

We report on a double-receiver-based pure rotational Raman (PRR) LiDAR that can, for the first time, obtain nighttime temperature profiles simultaneously at altitudes between 0.05 and 35 km. The LiDAR emits a 532.2-nm laser light and collects atmospheric backscatters with near-range (0.05–10 km) and far-range (8–35 km) receivers. The two receivers differ in telescope apertures and design of receiving optics. A unique calibration module with ~35.3- <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu $ </tex-math></inline-formula> rad angular positioning accuracy is developed for easy and convenient optical adjustment of the receiving optics. Typical LiDAR-retrieved temperature profiles on a clear-sky observational night are provided and compared with data from radiosonde launched at Wuhan Weather Station (~23.4-km northwest of the LiDAR site). For a 15-min temporal and 90-m spatial resolution, the 1- <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\sigma $ </tex-math></inline-formula> statistical uncertainty has a maximum of 1.9 K at 35 km, while the maximum absolute temperature deviation between the LiDAR and concurrent radiosonde reaches only 2 K at altitudes of 0.05–30 km under the conditions of stable atmosphere and no inversion layers. The temperature variability has been studied. The 15-min-to-15-min temperature variability tends to rise with increasing altitude in the altitude range from 2.2 to 35 km as a whole. In the troposphere, the significant variability is found to occur only at the inversion layer altitudes.