An intercomparison of lidar‐derived aerosol optical properties with airborne measurements near Tokyo during ACE‐Asia
An intercomparison of lidar‐derived aerosol optical properties with airborne measurements near Tokyo during ACE‐Asia
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DOI：
10.1029/2002jd003259
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发表时间：
2003-12
影响因子：
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通讯作者：
T. Murayama;S. Masonis;J. Redemann;T. Anderson;B. Schmid;J. Livingston;P. Russell;B. Huebert;
中科院分区：
文献类型：
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作者：
T. Murayama;S. Masonis;J. Redemann;T. Anderson;B. Schmid;J. Livingston;P. Russell;B. Huebert;
[1] 在ACE-Asia密集观测期（IOP）期间，在东京附近进行了地面激光雷达和飞机观测的比对实验。 2001年4月23日，四台三重后向散射激光雷达在东京地区同时运行，同时国家大气研究中心的C-130飞机在地面和东京西南相模湾上空6公里处以阶梯式飞行。 C-130 观测包包括跟踪太阳光度计和原位包，用于测量气溶胶光学特性、气溶胶尺寸分布、气溶胶离子成分和 SO2 浓度。三个偏振激光雷达表明，观测到的自由对流层中亚洲尘埃的适度浓度延伸至 8 公里的高度。我们发现激光雷达和原位 180° 反向散射浊度计观测结果在 532 nm 处的反向散射系数非常一致。对比表明，1.6~3.5 km之间的气溶胶层在中尺度上表现出非常稳定和均匀。我们还发现机载跟踪太阳光度计、原位光学仪器得出的气溶胶消光系数 (sa ± 0.03 km ± 1) 与行星边界层 (PBL) 上方激光雷达估算的气溶胶消光系数之间存在合理的一致性。我们还发现气溶胶去极化比（da）的垂直变化相当大，并且da与3.5公里以下的后向散射系数（da）之间呈负相关。对尺寸相关光学参数（例如，散射的精细模式分数）和气溶胶离子成分的机载测量表明，累积模式和粗模式（灰尘）气溶胶的混合比是观察到的 da 变化的主要原因。比对期间的气溶胶观测捕获了大气中以下三种类型的层： PBL（表面至 1.2-1.5 公里），其中以低 da（<10%）的细颗粒（主要是硫酸盐）为主；中间层（PBL顶部和3.5公里之间），细颗粒和尘埃颗粒在外部适度混合，产生中等da；上层（超过 3.5 公里）以灰尘为主，具有较高的 da (30%)。机载仪器在日本西部 4.5 至 6.5 公里处观察到大量尘埃层，发现激光雷达比为 50.4 ± 9.4 sr。这与稍后在该尘埃层经过东京时对同一尘埃层进行的夜间拉曼激光雷达测量非常吻合，该测量发现激光雷达比为 46.5 ± 10.5 sr。索引术语：0305 大气成分和结构：气溶胶和颗粒
[1] During the ACE-Asia intensive observation period (IOP), an intercomparison experiment with ground-based lidars and aircraft observations was conducted near Tokyo. On 23 April 2001, four Mie backscatter lidars were simultaneously operated in the Tokyo region, while the National Center for Atmospheric Research C-130 aircraft flew a steppedascent profile between the surface and 6 km over Sagami Bay southwest of Tokyo. The C-130 observation package included a tracking Sun photometer and in situ packages measuring aerosol optical properties, aerosol size distribution, aerosol ionic composition, and SO2 concentration. The three polarization lidars suggested that the observed modest concentrations of Asian dust in the free troposphere extended up to an altitude of 8 km. We found a good agreement in the backscattering coefficient at 532 nm among lidars and in situ 180� backscatter nephelometer observations. The intercomparison indicated that the aerosol layer between 1.6 and 3.5 km was a remarkably stable and homogenous in mesoscale. We also found reasonable agreement between the aerosol extinction coefficients (sa � 0.03 km � 1 ) derived from the airborne tracking Sun photometer, in situ optical instruments, and those estimated from the lidars above the planetary boundary layer (PBL). We also found considerable vertical variation of the aerosol depolarization ratio (da) and a negative correlation between da and the backscattering coefficient (da) below 3.5 km. Airborne measurements of size-dependent optical parameters (e.g., the fine mode fraction of scattering) and of aerosol ionic compositions suggests that the mixing ratio of the accumulation-mode and coarse-mode (dust) aerosols was primarily responsible for the observed variation of da. Aerosol observations during the intercomparison period captured the following three types of layers in the atmosphere: a PBL (surface to 1.2–1.5 km) where fine (mainly sulfate) particles with a low da (<10%) dominated; an intermediate layer (between the top of the PBL and 3.5 km) where fine particles and dust particles were moderately externally mixed, giving moderate da; and an upper layer (above � 3.5 km) where dust dominated, giving a high da (30%). A substantial dust layer between 4.5 and 6.5 km was observed just west of Japan by the airborne instruments and found to have a lidar ratio of 50.4 ± 9.4 sr. This agrees well with nighttime Raman lidar measurements made later on this same dust layer as it passed over Tokyo, which found a lidar ratio of 46.5 ± 10.5 sr. INDEX TERMS: 0305 Atmospheric Composition and Structure: Aerosols and particles