Test & Measurement
Airborne Snow Observatory: Measuring Snow Water Equivalent
Maps from NASA's Airborne Snow Observatory mission recently gave water resource managers in California precise information about snowpack and water availability that they have always wanted but never had before. The snowpack maps enabled them to achieve near-perfect water operations during the driest year in California history. The data-gathering technology aboard the observatory could improve water management for 1.5 billion people worldwide who rely on snowmelt for their water supply. The observatory's two instruments measure two properties most critical to understanding snowmelt runoff and timing. A scanning lidar system measures snow depth with lasers to determine the first property, snow water equivalent. Snow water equivalent represents the amount of water in the snow on a mountain. It is used to calculate the amount of water that will run off. An imaging spectrometer measures the second property, snow albedo. Snow albedo represents the amount of sunlight reflected and absorbed by snow. Snow albedo controls the speed of snowmelt and timing of its runoff.