Snow Sensing Using GPS

The Global Positioning System continuously transmits L-band signals to support real-time navigation users. These same signals are being tracked by networks of high-precision GPS instruments that were installed by geophysicists and geodesists to measure plate tectonics. Over 2000 of these systems have been deployed in the United States and make their data publicly available within 24 hours. We are currently using reflected signals recorded by these same GPS networks to measure snow depth. For most sites the footprint of the method is ~30 meter in radius with a snow depth precision of ~3 cm. These data complement other in situ sensors with smaller footprints. We currently operate 5 validation sites in Utah, Idaho, and Colorado. Comparisons between GPS snow depth retrievals and other sensors at these sites will be discussed. Results from ~100 GPS sites operated by the NSF EarthScope Plate Boundary Observatory will also be shown