Liu Yu-li, Xie Chen-bo, Shang Zhen, Zhao Ming, Cao Kai-fa, Sun Yue-sheng
Guang Pu Xue Yu Guang Pu Fen Xi. 2016 Jun;36(6):1978-86.
Due to the existence of the aerosol, the traditional method of measuring atmospheric temperature by using Rayleigh scattering technique has limitations in the low altitude. A pure rotational Raman lidar to get tropospheric temperature profiles is built. We carried out the atmospheric temperature observation in Beijing for two months. The atmospheric temperature profile was retrieved using the observed rotational Raman scattering signals. The effect of smooth window, calibration range and calibration constant on the retrieval precision of the atmospheric temperature was evaluated and analyzed. The results show that with the increase of smooth window, the mean absolute deviation between the lidar and radiosonde firstly decreases and then increases; in order to remove effectively the effect of random error in the return signals, while maintaining the fine vertical structure of temperature profile, it is better to choose the range between 600 and 1 200 m for smooth window. When calibration range is different, the mean absolute deviation between the lidar and radiosonde is varied, the relative variation of the deviation is about 0.07 K. When both calibration constant a and b increase or decrease, the mean deviation between the lidar and radiosonde increases; when one increases and another decreases, the mean deviation has a tendency to cancel each other out. The variance probability of a or b is not equal, and the variance of a and b is always contrary in the sign; the mean deviation is not sensitive to variance of a or b, and it is sensitive to the whole variance of a and b, about 91.7% of the mean deviation is in the range between -3 and 3 K. These results provide the theoretical basis for the selection of smooth window and calibration range in pure rotational Raman lidar data retrieval, and the reference for the error of actual temperature inversion result caused by lidar calibration constant.
由于气溶胶的存在，传统的利用瑞利散射技术测量大气温度的方法在低空存在局限性。搭建了一台用于获取对流层温度廓线的纯转动拉曼激光雷达。在北京进行了为期两个月的大气温度观测。利用观测到的转动拉曼散射信号反演大气温度廓线。评估并分析了平滑窗口、校准范围和校准常数对大气温度反演精度的影响。结果表明，随着平滑窗口增大，激光雷达与探空仪之间的平均绝对偏差先减小后增大；为有效去除回波信号中随机误差的影响，同时保持温度廓线良好的垂直结构，平滑窗口选择600～1200 m范围较好。校准范围不同时，激光雷达与探空仪之间的平均绝对偏差不同，偏差的相对变化约为0.07 K。当校准常数a和b同时增大或减小时，激光雷达与探空仪之间的平均偏差增大；当一个增大另一个减小，平均偏差有相互抵消的趋势。a或b的方差概率不相等，且a和b的方差符号始终相反；平均偏差对a或b的方差不敏感，对a和b的整体方差敏感，约91.7%的平均偏差在-3～3 K范围内。这些结果为纯转动拉曼激光雷达数据反演中平滑窗口和校准范围的选择提供了理论依据，也为激光雷达校准常数引起的实际温度反演结果误差提供了参考。
