Lidar ratio of Saharan dust over Cape Verde Islands: Assessment and error calculation
Lidar ratio of Saharan dust over Cape Verde Islands: Assessment and error calculation
复制标题
佛得角群岛撒哈拉沙尘的激光雷达比率：评估和误差计算
DOI：
10.1029/2010jd015435
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发表时间：
2011
影响因子：
--
通讯作者：
C. Toledano
中科院分区：
文献类型：
--
作者：
S. Groß;M. Wiegner;V. Freudenthaler;C. Toledano
在撒哈拉矿物尘实验第二阶段的框架内，在佛得角群岛测定了撒哈拉沙尘的激光雷达比Sp，以调查从源区运输的头几天可能发生的变化。利用德国路德维希-马克西米利安大学气象研究所的MULIS和POLIS两套拉曼激光雷达系统在355和532 nm同时测量的粒子消光系数和后向散射系数的垂直剖面反演激光雷达比值。由于以往的研究缺乏，本文的主要重点之一是详细阐述Sp检索的广泛误差分析。只有确定由检索输入参数的不确定性引起的系统误差，以及由信号噪声引起的Sp的统计误差，才能比较不同地点的测量结果，并深入了解尘埃激光雷达比随时间的变化。2008年1月28日至30日的一次强撒哈拉沙尘爆发满足了Sp评估和误差分析的适宜条件，在紫外和可见光谱区观测到沙尘层的粒子消光系数高达0.2-0.4 km−1。我们发现佛得角群岛在355和532 nm处的平均激光雷达尘埃比为63±6 sr。
[1] Lidar ratios Sp of Saharan dust were determined at the Cape Verde Islands in the framework of the second phase of the Saharan Mineral Dust Experiment to investigate possible changes during the first few days of transport from the source regions. Lidar ratios were retrieved from vertical profiles of particle extinction coefficients and backscatter coefficients measured simultaneously at 355 and 532 nm with the two Raman lidar systems MULIS and POLIS of the Meteorological Institute of the Ludwig-Maximilians-Universitat. As previous studies are lacking, one of the main foci of this paper is the elaboration of an extensive error analysis of the Sp retrieval. Only the determination of systematic errors, resulting from the uncertainties of the input parameters of the retrieval, and statistical errors of Sp due to signal noise allows one to compare measurements at different sites and to gain insight into the changes of the dust lidar ratio with time. Suitable conditions for the assessment of Sp and the error analysis were met during a strong Saharan dust outbreak from 28 to 30 January 2008, where particle extinction coefficients of the dust layer as high as 0.2–0.4 km−1 in the UV and visible spectral region were observed. We found an average lidar ratio of dust over Cape Verde Islands of 63 ± 6 sr at 355 and 532 nm.