A new approach to retrieval of aerosol size distributions and integral properties from SAGE II aerosol extinction spectra
A new approach to retrieval of aerosol size distributions and integral properties from SAGE II aerosol extinction spectra
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从 SAGE II 气溶胶消光光谱中检索气溶胶尺寸分布和积分特性的新方法
DOI：
10.1029/1999jd900455
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发表时间：
1999
影响因子：
--
通讯作者：
G. Yue
中科院分区：
文献类型：
--
作者：
G. Yue
提出了一种从平流层气溶胶和气体实验(SAGE)II气溶胶消光谱中反演气溶胶尺寸分布和积分性质的新方法。该方法假定气溶胶的尺寸分布可以用数密度的直方图作为颗粒大小的函数来近似。每个面元中的反演数密度被表示为四个或更少波长的SAGE II气溶胶消光的线性组合。加权线性组合中的系数是通过最小化一组测试大小分布的平均检索误差来获得的。同样的方法也被应用于从SAGE II气溶胶消光中提取气溶胶的表面积和体积密度。通过计算气溶胶的表面积和体积密度，研究了线性最小误差方法对6个气溶胶粒子尺度分布的反演精度。一般来说，随着可用于反演的与波长相关的消光测量的数量减少，反演误差增加。除了精度外，该方法还具有不需要初始猜测或权重函数的优点。此外，它非常简单和快速。另一个优点是，所提出的方法仍然适用于可靠的气溶胶消光次数少于4次的情况。本文给出的公式可以方便地被研究人员用来从不同高度的SAGE II气溶胶消光光谱中提取表面积和体积密度，以用于各种目的。所提出的新方法还可以扩展到从其他遥感系统中提取属性。讨论了该方法在仪器设计中的应用。
A new approach to the retrieval of aerosol size distributions and integral properties from Stratospheric Aerosol and Gas Experiment (SAGE) II aerosol extinction spectra is proposed. This method assumes that the aerosol size distribution can be approximated by a histogram of number density as a function of particle size. The retrieved number density in each bin is expressed as a linear combination of the SAGE II aerosol extinctions at four or fewer wavelengths. The coefficients in the weighted linear combination are obtained by minimizing the retrieval error averaged for a set of testing size distributions. The same method has been applied to retrieve aerosol surface area and volume densities from SAGE II aerosol extinctions. The retrieval accuracy was studied by calculating the aerosol surface area and volume densities for six aerosol size distributions retrieved by using the proposed linear minimizing error method. In general, the retrieval error increases with the decreasing number of wavelength-dependent extinction measurements available for retrieval. Besides accuracy, the proposed method has the advantage of not requiring an initial guess or a weighting function. Furthermore, it is very simple and fast. Another advantage is that the proposed method can still be applied to the case when the number of reliable aerosol extinction is less than four. The formulas presented in this paper can be used easily by investigators to retrieve surface area and volume densities from SAGE II aerosol extinction spectra at different altitudes for a variety of purposes. The proposed new method can also be extended to retrieve properties from other remote sensing systems. The application of the proposed method for instrument design is discussed.