Photography and the Science of Snowflakes, Raindrops and Aerosols

From the early nineteenth century to present-day, photography has been an essential tool for visualizing, documenting and analyzing a variety of atmospheric phenomena. Indeed, photography and atmospheric science have had an enduring relationship, one that has propelled innovations in photographic technology while also advancing scientific understanding of weather and climate. In this talk, I will focus on the historical relationship between photography and its role in exposing the physical properties of snowflakes, raindrops and aerosols. This extraordinary historical relationship has many facets: individuals who used cameras in novel ways; scientific problems that spurred new photographic technologies; and new understanding of atmospheric aerosols, among the least understood components of the climate system. In my presentation, I will tell the story of Wilson Bentley, who developed innovative ways to photograph snowflakes, which he fondly called “miracles of beauty.” Bentley made the first microphotograph of a snowflake and produced an extraordinary collection of snowflake photographs that are known for their visual beauty as well as their scientific content. I will also talk about the historical development and application of a variety of cameras that were designed for unique purposes. These cameras include the multi-angle snowflake camera, which was designed to measure the fall speed of snowflakes; and the fast-line scanning camera, which was designed to measure the two-dimensional shape of a raindrop. Finally, I will discuss the various techniques that are used to analyze the photographic information and to reach conclusions that can be used to improve numerical modeling of clouds and their role in the climate system.