Stratospheric aerosol particle size information in Odin-OSIRIS limb scatter spectra
Stratospheric aerosol particle size information in Odin-OSIRIS limb scatter spectra
复制标题
Odin-OSIRIS 临边散射光谱中的平流层气溶胶粒径信息
DOI：
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发表时间：
2013
期刊：
影响因子：
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通讯作者：
D. Degenstein
中科院分区：
文献类型：
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作者：
L. Rieger;A. Bourassa;D. Degenstein
抽象的。Odin卫星上的光学光谱仪和红外成像系统(OSIRIS)现在已经进行了十多年的肢体散射测量，用于提取版本5的平流层气溶胶消光产品。该乘积使用典型的颗粒尺寸分布来计算散射截面和散射相函数，用于正演模型计算。在这项工作中，系统地研究了关于平流层气溶胶的OSIRIS测量的信息量，目的是反演颗粒尺寸信息和消光系数。研究了在不同波长和散射角下使用测量的好处，发现结合1530 nm辐射度测量是稳健地提取颗粒尺寸信息的关键。还发现，在Odin轨道上的不同太阳几何位置同时使用OSIRIS测量几乎没有额外的好处。在此基础上，提出了一种改进的气溶胶反演算法，该算法将气溶胶消光系数与对数正态粒子尺寸分布的模式半径相结合。将这些结果与SAGE III的一致测量结果进行比较，结果表明，在大部分气溶胶层上，反演的消光系数在约10%以内，这与版本5相当。当转换为Angstrom系数时，反演的粒子尺寸与SAGE II在较短波长下的测量结果显示出很好的定性一致性。
Abstract. The Optical Spectrograph and InfraRed Imaging System (OSIRIS) onboard the Odin satellite has now taken over a decade of limb scatter measurements that have been used to retrieve the version 5 stratospheric aerosol extinction product. This product is retrieved using a representative particle size distribution to calculate scattering cross sections and scattering phase functions for the forward model calculations. In this work the information content of OSIRIS measurements with respect to stratospheric aerosol is systematically examined for the purpose of retrieving particle size information along with the extinction coefficient. The benefit of using measurements at different wavelengths and scattering angles in the retrieval is studied, and it is found that incorporation of the 1530 nm radiance measurement is key for a robust retrieval of particle size information. It is also found that using OSIRIS measurements at the different solar geometries available on the Odin orbit simultaneously provides little additional benefit. Based on these results, an improved aerosol retrieval algorithm is developed that couples the retrieval of aerosol extinction and mode radius of a log-normal particle size distribution. Comparison of these results with coincident measurements from SAGE III shows agreement in retrieved extinction to within approximately 10% over the bulk of the aerosol layer, which is comparable to version 5. The retrieved particle size, when converted to Angstrom coefficient, shows good qualitative agreement with SAGE II measurements made at somewhat shorter wavelengths.