A Low-Cost, Open-Source Snowflake Imager

Falling and blowing snow are challenging hydrometeors to observe at the surface. The widespread lack of observations of these processes limits the development and verification of microphysical parameterizations and retrievals, hindering the development of the next generation of weather and climate models. Historically, a number of techniques have been used to observe ice crystals at the surface. Ranging from capturing hydrometeors in formvar solution to direct and indirect imaging of snowflakes, each instrument has its advantages and disadvantages. While analog devices are cheaper to develop and deploy, they are also more cumbersome to analyze. Conversely, digital instruments such as re-purposed aircraft probes or newer imagers such as the Multi-Angle Snowflake Camera (MASC) ease analysis but are prohibitively expensive for widespread deployments for educational or research purposes. These instruments are also challenged in wind-blown settings where significant interaction of the flow can impact the sampling of hydrometeors.

Ideally, a low-cost imager should exist to allow for basic properties (crystal habit, size, and orientation) of these hydrometeors to be observed. Herein, the design choices for a new snowflake imager will be described. Designed to take photos of falling and blowing snow particles, a machine vision camera is paired to a high-speed LED strobe to image snowflakes in flight regardless of environmental wind speed. Fundamental aspects of the design include the use of off the shelf systems, 3d printed parts, and open-source code. This will lower the design cost to a point that facilitates the deployment for both educational and research purposes. In the spirit of open design, plans will be made publicly available so devices can be built at other institutions.