Abstract

The intensity and polarization of the twilight-sky background were measured during the epoch of “purple lights” after the Raikoke volcanic eruption in the summer of 2019. The increase in brightness paired with the decrease in polarization was registered, and the changes were especially noticeable in the dusk segment. The altitude distribution of aerosol particles and their mean size were found with previously developed techniques. The median radius of the lognormal distribution (0.11 μm) is typical of the background conditions or weak eruptions; however, the aerosols were mostly concentrated in the upper troposphere and near the tropopause rather than in the stratosphere. From comparison with satellite data obtained almost a decade ago after similar eruptions (like those of the Kasatochi volcano and others), it has been shown that the properties of their aerosols are similar, which confirms that the purple light phenomenon observed in 2019 was of volcanic origin.

中文翻译：

---

火山后气溶胶：暮光-天空极化法测量高度和粒径

摘要

在2019年夏季Raikoke火山喷发后的“紫色光”时期测量了暮色天空背景的强度和偏振。记录到亮度的增加与偏振的减少相对应，并且变化尤为明显在黄昏段。气溶胶颗粒的高度分布及其平均尺寸是通过先前开发的技术发现的。对数正态分布的中值半径（0.11μm）是背景条件或弱喷发的典型特征；然而，气溶胶主要集中在对流层上部和对流层顶附近，而不是在平流层中。通过与近十年前类似喷发（如Kasatochi火山和其他喷发）获得的卫星数据进行比较，