Stratospheric Transparency Derived from Total Lunar Eclipse Colors, 1801–1881

Abstract

A catalog of the observed colors of the totally eclipsed Moon during the period 1665 - 1800 has been prepared from published contemporary reports. Nearly all of the observations were made from Europe. Usable eclipses number 36 in all, or on average, about one eclipse every 4 years. The hue and intensity of the faint illumination of the Moon's disk during totality yield a measure of the aerosol optical depth of the Earth's stratosphere. Unlike the 19th and 20th centuries, the period under study showed a relatively clear stratosphere at nearly all times. Independent but less direct evidence from Greenland ice cores, which contain an annual record of aerosol fallout from large volcanic eruptions, confirms that this was a period of very few, if any, large stratosphere-penetrating volcanic eruptions.