Scientists at NASA’s Jet Propulsion Laboratory have found one more tool to help monitor California's water supply during this drought year. They’re using GPS to measure the weight of the snowpack in the Sierra Nevada Mountains.
The JPL team looked at data from dozens of GPS receivers. They compared the ground level when the snowpack was at its largest to the level when much of the snow had melted away.
The earth sags in places where the snowpack is heavy so the difference in height allowed them to deduce just how much water had been stored there.
The Sierra Nevada snowpack is one of the most important sources of water for the state and scientists and officials pay close attention to its size. JPL already tracks it using images from airplanes and space satellites and state officials physically survey the snow at several locations.
But project leader Donald Argus says the benefit of GPS is that it provides a constant real-time measure that covers the entire mountain range and it’s more accurate than leading computer models.
"I don’t know if there’s a comprehensive estimate like this," he said. "The network is already out there of GPS receivers so we can use it right away."
He hopes water officials in California can apply the measurement to plan for water scarcity, track groundwater levels in the Central Valley, and even make hydroelectric power generation more efficient.