多条转动拉曼谱线雷达测量对流层大气温度

由于对流层大气中气溶胶的存在,传统的利用大气中瑞利散射和振动拉曼散射测量大气温度的方法具有一定的局限性,然而利用大气N2和O2分子的的转动拉曼信号获得大气温度信息的方法不受对流层大气中气溶胶的影响.因此利用N2和O2分子纯转动拉曼散射激光雷达开展了测量对流层下部温度分布的实验研究.现有的转动拉曼雷达系统基本上是通过获取单一的转动拉曼谱线来反演大气温度,这就导致了系统的信噪比低,不能很好的反演温度.作者在双光栅单色仪的基础上提出了一种新的雷达信号分光系统.这种新的分光系统的每条通道所获得的信号并不是单独的转动拉曼谱线,而是多条转动拉曼谱线之和,这样就能提高整个系统的信噪比.在较小的激光能量和小口径望远镜的情况下,利用这种方法,雷达系统可以在几公里内获得较好的信噪比.最后实验得到了对流层0.3～5 km高度内的大气温度分布,它与球载无线电探空仪比较,二者一致性较好.

Raman Lidar Measuring Tropospheric Temperature Profiles With Many Rotational Raman Lines

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 from this 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.