Direct-detection Doppler wind measurements with a Cabannes-Mie lidar: b. Impact of aerosol variation on iodine vapor filter methods.
Direct-detection Doppler wind measurements with a Cabannes-Mie lidar: b. Impact of aerosol variation on iodine vapor filter methods.
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DOI：
10.1364/ao.46.004444
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发表时间：
2007-07
期刊：
影响因子：
1.9
通讯作者：
C. She;J. Yue;Zhaoai Yan;J. Hair;Jin-Jia Guo;Songhua Wu;Zhishen Liu
中科院分区：
文献类型：
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作者：
C. She;J. Yue;Zhaoai Yan;J. Hair;Jin-Jia Guo;Songhua Wu;Zhishen Liu
大气视距（LOS）风测量方法采用非相干Cabannes- Mie激光雷达，带有三个频率分析仪，两个双边Fabry-Perot干涉仪，一个在1064 nm (IR-FPI)，另一个在3555 nm (UV-FPI)，以及一个碘蒸汽过滤器（IVF）在532 nm，利用单吸收边，单边缘（se-IVF），或两个吸收边，双边（de-IVF），在一篇论文中被考虑。[j]，假设已知大气温度和气溶胶混合比，Rb。研究了温度和气溶胶变化对LOS风测量的不确定性的影响，发现虽然温度变化的影响很小，但R(b)的变化会导致IVF系统的风测量出现重大误差。因此，提出了将可靠的R(b)确定纳入风测量的方法，以及对风测量不确定性影响的评估。与体外受精方法不同，研究人员可以利用FPI方法的设计灵活性来脱敏IR-FPI的分子散射或UV-FPI的气溶胶散射。因此，对于这些配置，FPI方法中R(b)变化引起的额外风测量不确定性可以忽略不计。假设来自Cabannes散射的100,000个光子，并考虑到本文IVF方法中纳入的Rb测量，发现在无气溶胶的空气中，低风速下的最低风不确定性仍然是UV-FPI，比de-IVF低约32%。对于0.050.07，IR-FPI优于所有其他方法。除了对高风速条件下的LOS风不确定性进行比较外，还讨论了在阳光条件下在可见光波段运行风激光雷达所需的合适且容易获得的窄带滤波器；对于实际的激光雷达系统，使用这样的滤波器，由于晴空背景导致的LOS风测量的退化估计为5%或更少。
Atmospheric line-of-sight (LOS) wind measurement by means of incoherent Cabannes- Mie lidar with three frequency analyzers, two double-edge Fabry-Perot interferometers, one at 1064 nm (IR-FPI) and another at 355 nm (UV-FPI), as well as an iodine vapor filter (IVF) at 532 nm, utilizing either a single absorption edge, single edge (se-IVF), or both absorption edges, double edge (de-IVF), was considered in a companion paper [Appl. Opt. 46, 4434 (2007)], assuming known atmospheric temperature and aerosol mixing ratio, Rb. The effects of temperature and aerosol variations on the uncertainty of LOS wind measurements are investigated and it is found that while the effect of temperature variation is small, the variation in R(b) can cause significant errors in wind measurements with IVF systems. Thus the means to incorporate a credible determination of R(b) into the wind measurement are presented as well as an assessment of the impact on wind measurement uncertainty. Unlike with IVF methods, researchers can take advantage of design flexibility with FPI methods to desensitize either molecular scattering for IR-FPI or aerosol scattering for UV-FPI. The additional wind measurement uncertainty caused by R(b) variation with FPI methods is thus negligible for these configurations. Assuming 100,000 photons from Cabannes scattering, and accounting for the Rb measurement incorporated into the IVF method in this paper, it is found that the lowest wind uncertainty at low wind speeds in aerosol-free air is still with UV-FPI, ~32% lower than with de-IVF. For 0.050.07, the IR-FPI outperforms all other methods. In addition to LOS wind uncertainty comparison under high wind speed conditions, the need of an appropriate and readily available narrowband filter for operating the wind lidar at visible wavelengths under sunlit condition is discussed; with such a filter the degradation of LOS wind measurement attributable to clear sky background is estimated to be 5% or less for practical lidar systems.