How Does Snowpack Evolution Affect Climate?

Current uncertainties associated with climate model projections can be attributed in part to incomplete understanding of specific climate feedbacks, such as the snow albedo feedback. Fluctuations in snow albedo [reflectivity]... [ view full abstract ]

Current uncertainties associated with climate model projections can be attributed in part to incomplete understanding of specific climate feedbacks, such as the snow albedo feedback. Fluctuations in snow albedo [reflectivity] caused by changes to the snowpack impact local, regional and global climates. Ground-based snow albedo data at high temporal and spatial resolution are needed to address gaps in model representation as well as in understanding of overall snow evolution processes. In this study, a network of 20 volunteer citizen scientists located throughout the state of New Hampshire were trained to collect daily snow albedo, snow depth and snow density measurements starting in winter 2011-2012 and continuing to the present. Volunteers in the network receive training and education, low-cost measuring equipment and access to an interactive website where data are entered, visualized and downloaded. Roughly half of the participants in the network are middle or high school teachers and students while the other half are volunteer weather observers who are already part of the CoCoRAHS (Community Collaborative Rain, Hail & Snow) Network. Unfortunately, some participants struggle to make daily albedo measurements, but overall the majority contribute consistent, high quality albedo data that are valuable for research and education purposes. Snow albedo values range from 0.78-0.99 for newly fallen snow, 0.34-0.88 for aged snow and 0.09-0.39 for snow-free conditions. Collectively, albedo values are found to decrease with increasing snow age, increasing snow density and increasing air temperature with much variability across the state and through time. These relationships inform an empirical formula that uses snow age, snow depth and air temperature to predict albedo. This research will increase understanding of snow albedo evolution processes as well as improve the simulation of snowpack evolution by regional climate models.