A Combined Rotational Raman-Rayleigh Lidar for Atmospheric Temperature Measurements Over 5-80 km With Self-Calibration

作者:Li, Yajuan; Lin, Xin; Song, Shalei*; Yang, Yong; Cheng, Xuewu; Chen, Zhenwei; Liu, Linmei; Xia, Yuan; Xiong, Jun; Gong, Shunsheng; Li, Faquan
来源:IEEE Transactions on Geoscience and Remote Sensing, 2016, 54(12): 7055-7065.
DOI:10.1109/TGRS.2016.2594828

摘要

A combined lidar system on the basis of conventional Rayleigh lidar has been extended by two rotational Raman (RR) channels for nocturnal atmospheric temperature measurements from 5 to 80 km over Wuhan, China (30.5 degrees N, 114.5 degrees E). An overlapping altitude range of about 10 km is obtained with the RR-technique temperatures reaching upward to 40 km and the Rayleigh-integration-technique temperatures above 30 km. Temperature values obtained by two different mechanisms match nicely in the overlapping area. By using a data-merge method, complete temperature profiles covering widely from 5 to 80 km are obtained for the observation of the thermal structure and perturbations from the troposphere up to the mesosphere. Based on the overlapping-region (30-40 km) data obtained from this combined RR-Rayleigh lidar system and Rayleigh-integration-technique temperatures initialized with model data at an upper height (90 km), we develop a self-calibration method for the determination of the system-dependent constants for RR temperature retrieval. Compared with the conventional radiosonde calibration method, the self-calibration obtained in the overlap region of both lidar temperature measurement techniques can be extrapolated to the lower temperatures in the tropopause region by using the simpler two-constant calibration function. With this new calibration method, the combined lidar system can perform independent and accurate atmospheric temperature measurements when a coincident (in time and space) radiosonde is not available, as it is often the case. This combined RR-Rayleigh lidar thus has the potential for long-term studies of atmospheric thermal structure and associate perturbations.