Josset Damien, Rogers Raymond, Pelon Jacques, Hu Yongxiang, Liu Zhaoyan, Omar Ali, Zhai Peng-Wang
SSAI, Hampton, VA 23681, USA.
Opt Express. 2011 Sep 12;19(19):18696-706. doi: 10.1364/OE.19.018696.
We are demonstrating on a few cases the capability of CALIPSO to retrieve the 532 nm lidar ratio over the ocean when CloudSat surface scattering cross section is used as a constraint. We are presenting the algorithm used and comparisons with the column lidar ratio retrieved by the NASA airborne high spectral resolution lidar. For the three cases presented here, the agreement is fairly good. The average CALIPSO 532 nm column lidar ratio bias is 13.7% relative to HSRL, and the relative standard deviation is 13.6%. Considering the natural variability of aerosol microphysical properties, this level of accuracy is significant since the lidar ratio is a good indicator of aerosol types. We are discussing dependencies of the accuracy of retrieved aerosol lidar ratio on atmospheric aerosol homogeneity, lidar signal to noise ratio, and errors in the optical depth retrievals. We are obtaining the best result (bias 7% and standard deviation around 6%) for a nighttime case with a relatively constant lidar ratio (in the vertical) indicative of homogeneous aerosol type.
我们通过几个案例展示了CALIPSO在将CloudSat表面散射截面用作约束条件时，获取海洋上空532纳米激光雷达比的能力。我们介绍了所使用的算法，并与美国国家航空航天局（NASA）机载高光谱分辨率激光雷达反演的柱状激光雷达比进行了比较。对于此处展示的三个案例，二者吻合度相当不错。相对于高光谱分辨率激光雷达（HSRL），CALIPSO的532纳米柱状激光雷达比平均偏差为13.7%，相对标准偏差为13.6%。考虑到气溶胶微物理特性的自然变异性，这样的精度水平意义重大，因为激光雷达比是气溶胶类型的良好指标。我们正在探讨反演气溶胶激光雷达比的精度对大气气溶胶均匀性、激光雷达信噪比以及光学深度反演误差的依赖性。对于一个夜间案例，我们获得了最佳结果（偏差7%，标准偏差约为6%），该案例中激光雷达比（在垂直方向上）相对恒定，表明气溶胶类型均匀。
