NASA and Snow
NASA’S airborne snow observatory comes to town
Dr. Thomas Painter, Lead Investigator for The NASA Airborne Snow Observatory (ASO), says he and his team have found a way to determine precisely how much water is in a given High Sierra basin at a given time.
After his team flies a particular drainage, it takes them just 24 hours to collect the data, feed it into a computerized model called ISNOBAL, and generate a short and long-term forecast for how much of that water will manifest as runoff in a river in that basin. Four and a half years into the project, Dr. Painter says his team is able to predict the volume of annual runoff in a given river drainage with as little as 2 percent error. The increased accuracy of those predictions may allow water managers to maximize efficient use of California’s water supply.
The team conducts aerial snowpack surveys from a King Air plane that is specially rigged to allow an imaging spectrometer and a scanning LiDAR machine to capture detailed imagery of the topography below the plane.
LiDAR captures the distance between the plane and the surface of the ground by recording the length of time needed for a pulse of light to travel from the machine to the ground’s surface, and back. This information, collected continually, is then used to create an image of the topography below.
During the winter months, flight surveys are conducted monthly. That data is then entered into ISNOBAL, which compares the “snow-on” data with a snow-free topographic map of the basin being analyzed created from data collected by the same means in the summer of 2012. The difference between the two maps is the volume of snow in the basin at a given time.
