Elevation readings captured by satellites confirm that glaciers in the western United States are fading away at a worrisome rate.
The fade-out isn’t a surprise, considering the rise in global mean temperatures that’s ascribed to climate change. The new twist has to do with how the measurements were made.
University of Washington researcher David Shean looked back at satellite readings that have been amassed in databases, plus fresh readings that are being taken by DigitalGlobe’s constellation of GeoEye and WorldView satellites.
An analysis of the data, facilitated with NASA’s Ames Stereo Pipeline software, produces a 3-D elevation model of mountainous terrain. The method supplements other techniques to estimate glacier size, including area measurements based on aerial imagery and depth measurements made using stakes in the snow.
The result is a year-by-year record tracing the ups and downs of a glacier.