The cores we gather from Greenland will get shipped back to Snow Optics Laboratory (SOL), at NASA’s Jet Propulsion Laboratory, in Pasadena. SOL is designed to analyze snow and ice samples for impurity content. Here, McKenzie will separate impurities between black carbon and other light-absorbing components, like mineral dust. She then can use the optical and chemical properties to tie back the deposited impurities to their source—black carbon from industry or from wildfire. This “source attribution” utilizes a combination of advanced instrumentation and numerical modeling.
Once the impurity content has been determined, the impact due to the impurities can be quantified. Determining the additional energy light-absorbing impurities contribute to melt, known as the radiative forcing, requires a combination of field measured (snow grain size, density, and reflectivity), lab measured (impurity content and characteristics), and modeled (radiative transfer) components.
Living on the ice sheet in summer exposes you to big views of flat white, to deafening silence on rare occasions when it’s not windy, to incredible brightness with high-altitude sun reflecting 60-80 percent right back upward, 24 hours a day. Creature comforts are important, as you’re not bathing so often. To sleep after long days working in the field, we'll need to wear dark face masks during bright nights. It is by no means a pleasure cruise, but it's better than living next to a wildfire.
Jason Box is a professor at the Geological Survey of Denmark and Greenland. McKenzie Skiles is a doctoral candidate in the UCLA Department of Geography, and manager of Snow Optics Lab at the Jet Propulsion Lab at the California Institute of Technology.