Su Jia, Zhang Yin-chao, Hu Shun-xing, Cao Kai-fa, Zhao Pei-tao, Wang Shao-lin, Xie Jun
Key Lab of Atmospheric Optics, Anhui Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Hefei 230031, China.
Guang Pu Xue Yu Guang Pu Fen Xi. 2008 Aug;28(8):1781-5.
Due to lower tropospheric aerosols, the Rayleigh and vibrational Raman methods can't measure lower tropospheric temperature profiles accurately. By using N2 and O2 molecular pure rotational Raman scattering signals, lower tropospheric temperature profiles can be gained without influence of lower tropospheric aerosols. So we decide to use a pure rotational Raman Lidar to get lower tropospheric temperature profiles. At present, because the most light-splitting systems of pure rotational Raman Lidar measure temperature by gaining a single rotational Raman line, the signal to noise ratio (SNR) of these Lidar systems are very low. So we design a new kind of Lidar light-splitting system which can sum different rotational Raman lines and it can improve SNR And we can find the sensitivity of the temperature of the ratios of multi rotational Raman lines is as same as single rotational Raman line's through theoretical analysis. Moreover, we can obtain the temperature profiles with good SNR fromthis new the system with a normal laser and a small telescope up to several kilometers. At last, with the new light-splitting system, the lower tropospheric temperature profiles are measured from 0.3 km to 5 km altitude. They agree well with radiosonde observations, which demonstrate the results of our rotational Raman lidar are reasonable.
由于对流层低层气溶胶的存在，瑞利散射和振动拉曼散射方法无法准确测量对流层低层的温度廓线。利用N2和O2分子的纯转动拉曼散射信号，可以获取不受对流层低层气溶胶影响的对流层低层温度廓线。因此，我们决定使用一台纯转动拉曼激光雷达来获取对流层低层温度廓线。目前，由于大多数纯转动拉曼激光雷达的分光系统通过获取单一转动拉曼线来测量温度，这些激光雷达系统的信噪比非常低。所以我们设计了一种新型的激光雷达分光系统，它可以对不同的转动拉曼线进行求和，从而提高信噪比。通过理论分析发现，多转动拉曼线比值的温度灵敏度与单转动拉曼线的相同。此外，利用一台普通激光器和一台小望远镜，我们可以从这个新系统中获得信噪比良好的温度廓线，测量高度可达数公里。最后，使用新的分光系统，在0.3公里至5公里的高度范围内测量了对流层低层温度廓线。它们与无线电探空仪观测结果吻合良好，这表明我们的转动拉曼激光雷达测量结果是合理的。
