Abstract. In this work a novel approach to determine the particle size distribution (PSD) parameters of stratospheric sulfate aerosols is presented. For this, ratios of extinction coefficients obtained from SAGE III/ISS solar occultation measurements at 449 nm, 756 nm and 1544 nm were used to retrieve the mode width and median radius of a size distribution assumed to be monomodal lognormal. The estimated errors at the peak of the stratospheric aerosol layer on average lie between 20 % and 25 % for the median radius and 5 % and 7 % for the mode width. The results are consistent in magnitude with other retrieval results from the literature, but a robust comparison is difficult, mainly because of differences in temporal and spatial coverage. Other quantities like number density and effective radius were also calculated. A major advantage of the described method over other retrieval techniques is that both the median radius and the mode width can be retrieved simultaneously, without having to assume one of them, due to the broad wavelength spectrum covered by the SAGE III/ISS measurements. Also the extinction coefficients from SAGE III/ISS solar occultation measurements, on which the retrieval is based, are calculated without a priori assumptions about the PSD. For those reasons, the data produced with the presented retrieval technique may be a valuable contribution to better understand the variability of stratospheric aerosol size distributions, e.g. after volcanic eruptions. While this study focuses on describing the retrieval method and a future study will discuss the PSD parameter data set produced in depth, some exemplary results for background conditions in June 2017 are shown.

中文翻译：

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使用SAGE-III / ISS消光测量在三个波长处检索平流层气溶胶粒径分布参数

摘要。在这项工作中，提出了一种确定平流层硫酸盐气溶胶粒径分布（PSD）参数的新颖方法。为此，使用在449 nm，756 nm和1544 nm处从SAGE III / ISS太阳掩星测量中获得的消光系数之比来检索假定为单峰对数正态的尺寸分布的众数宽度和中值半径。平流层气溶胶层峰值的估计误差平均为中值半径在20％至25％之间，模式宽度为5％至7％。结果与文献中的其他检索结果在大小上是一致的，但是主要由于时间和空间覆盖范围的差异，很难进行可靠的比较。还计算了其他数量，例如数密度和有效半径。相对于其他检索技术，所描述方法的主要优势在于，由于SAGE III / ISS测量所涵盖的宽光谱范围，可以同时检索中值半径和模式宽度，而不必假设其中之一。同样，在没有先验假设关于PSD的情况下，计算了基于SAGE III / ISS太阳掩星测量的消光系数。出于这些原因，使用提出的检索技术产生的数据可能对更好地了解平流层气溶胶粒径分布的变化（例如火山喷发后）具有重要意义。尽管本研究着重于描述检索方法，而未来的研究将深入探讨PSD参数数据集，