Nakazato Masahisa, Nagai Tomohiro, Sakai Tetsu, Hirose Yasuo
Meteorological Research Institute, Tsukuba, Ibaraki, Japan.
Appl Opt. 2007 Apr 20;46(12):2269-79. doi: 10.1364/ao.46.002269.
A UV ozone differential-absorption lidar (DIAL) utilizing a Nd:YAG laser and a single Raman cell filled with carbon dioxide (CO(2)) is designed, developed, and evaluated. The generated wavelengths are 276, 287, and 299 nm, comprising the first to third Stokes lines of the stimulated Raman scattering technique. The correction terms originated from the aerosol extinction, the backscatter, and the absorption by other gases are estimated using a model atmosphere. The experimental results demonstrate that the emitted output energies were 13 mJ/pulse at 276 nm and 287 nm and 5 mJ/pulse at 299 nm, with pump energy of 91 mJ/pulse and a CO(2) pressure of 0.7 MPa. The three Stokes lines account for 44.0% of the available energy. The use of argon or helium as a buffer gas in the Raman cell was also investigated, but this leads to a dramatic decrease in the third Stokes line, which makes this wavelength practically unusable. Our observations confirmed that 30 min of integration were sufficient to observe ozone concentration profiles up to 10 km. Aerosol extinction and backscatter correction are estimated and applied. The aerosol backscatter correction profile using 287 and 299 nm as reference wavelengths is compared with that using 355 nm. The estimated statistical error is less than 5% at 1.5 km and 10% at 2.6 km. Comparisons with the operational carbon-iodine type chemical ozonesondes demonstrate 20% overestimation of the ozone profiles by the DIAL technique.
设计、开发并评估了一种利用Nd:YAG激光器和充满二氧化碳（CO₂）的单个拉曼池的紫外臭氧差分吸收激光雷达（DIAL）。产生的波长为276、287和299纳米，包括受激拉曼散射技术的第一至第三斯托克斯线。利用标准大气估算了源自气溶胶消光、后向散射以及其他气体吸收的校正项。实验结果表明，在泵浦能量为91 mJ/脉冲且CO₂压力为0.7 MPa的情况下，276纳米和287纳米处的发射输出能量为13 mJ/脉冲，299纳米处为5 mJ/脉冲。这三条斯托克斯线占可用能量的44.0%。还研究了在拉曼池中使用氩气或氦气作为缓冲气体的情况，但这会导致第三斯托克斯线急剧下降，使得该波长几乎无法使用。我们的观测结果证实，30分钟的积分时间足以观测到高达10千米的臭氧浓度剖面。估算并应用了气溶胶消光和后向散射校正。将以287纳米和299纳米作为参考波长的气溶胶后向散射校正剖面与以355纳米作为参考波长的剖面进行了比较。在1.5千米处估算的统计误差小于5%，在2.6千米处为10%。与运行中的碳碘型化学臭氧探空仪的比较表明，DIAL技术对臭氧剖面的估算高估了20%。
