Were Noctilucent Clouds Caused by the Krakatoa Eruption? A Case Study of the Research Problems before 1885

Abstract

It is known that noctilucent clouds were first observed in 1885, two years after the great Krakatoa eruption in the Sunda Straits. The preeminent question of whether noctilucent clouds appeared before 1885 is studied here in detail. Using various literature sources and observational records for the nineteenth century from several observers it can be shown that before 1885 noctilucent clouds were never described in the literature. The so-called bright nights or Leuchtstreifen phenomenon was well known in the nineteenth century, but no observer described any structures that can be identified as noctilucent clouds. This result makes it clear that the noctilucent clouds seen in 1885 were the first such observations to be made. A possible increase in frequency of occurrence can be estimated from the year of discovery up to the present day.