由于气溶胶的影响, 传统的瑞利散射法测量低空大气温度有一定的局限, 为此开展了纯转动拉曼法测量低空大气温度。 利用纯转动拉曼激光雷达在北京进行了2个月的大气温度观测, 由观测数据反演了温度廓线。 在基于N2和O2的纯转动拉曼谱线特征进行大气温度反演过程中, 分析了平滑窗口、 定标范围和定标常数对温度反演精度的影响。 结果显示随着平滑窗口的增大, 雷达和无线电探空仪测量的温度之间的平均绝对偏差先减小后增加, 为有效去除信号中随机误差的影响, 同时保留温度廓线的垂直结构, 平滑窗口应选择600~1 200 m比较好。 定标范围不同, 雷达和无线电探空仪测量的温度之间的平均绝对偏差就不同, 相对变化约为0.07 K。 当定标常数a, b都增大或都减小时, 雷达和无线电探空仪测量的温度之间的平均偏差增大, 当一个增大另一个减小时, 平均偏差相互抵消; a, b的变化不是等几率的, 在符号上总是相反的; 平均偏差对a的变化不敏感, 对b的变化也不敏感, 对a与b的整体变化敏感, 约91.7%平均偏差落入-3~3 K之间。 该研究分析结果对纯转动拉曼激光雷达数据反演中涉及的平滑窗口、 定标范围的选择提供了理论依据, 对激光雷达定标常数造成实际温度反演结果的误差提供了参考。

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.