Snow science in support of U.S. water supply

the climate. Scientists have detected changes in snow quantity and snowmelt timing that track with other changes prompted by Earth’s warming climate. While satellites are not able to measure snow-water equivalent accurately over all snowy landscapes, satellites have monitored the extent of seasonal snow-covered areas for decades. Since 1967, Northern Hemisphere spring snow cover has declined by about 1 million square miles. Loss of snow cover results in Earth absorbing more sunlight, accelerating the planet’s warming.

In the air, on the ground
The instruments and techniques developed in campaigns such as SnowEx could one day result in a snow-observing space mission. “We will also figure out a better way to optimize the use of existing satellites to make measurements,” said Jared Entin, program manager of the Terrestrial Hydrology Program at NASA Headquarters.

Five aircraft with a total of 10 different sensors are part of the SnowEx campaign. From an operations base at Peterson Air Force Base, Colorado Springs, SnowEx will deploy a P-3 Orion aircraft operated by the Scientific Development Squadron ONE (VXS-1), stationed at the Naval Air Station Patuxent River, Maryland. High-altitude NASA jets will fly from NASA’s Johnson Space Center in Houston, and NASA’s Armstrong Flight Research Center in Palmdale, California. A King Air and a Twin Otter will fly out of Grand Junction, Colorado.

The planes will carry one passive and four active microwave sensors that are good at measuring snow-water equivalent in dry snow, but are less optimal for measuring snow in forests or light snow cover; a thermal infrared camera and a remote thermometer (KT-15) for measuring surface temperature; a laser instrument that is good at measuring snow depth and snow water equivalent through trees; an imaging spectrometer which measures snow albedo — the amount of sunlight reflected and absorbed by snow, which controls the speed of snowmelt and the timing of its runoff. The King Air carries the Airborne Snow Observatory from NASA’s Jet Propulsion Laboratory in Pasadena, California. ASO is the first remote sensing system to ever measure snow depth, snow water equivalent and snow albedo across entire mountain basins, and has uniquely quantified snow water equivalent over mountainous regions since 2013. 

The field portion of the campaign is based in Grand Mesa and Senator Beck Basin. Scientists will use measurement and sampling procedures that will allow the team to validate the remotely-sensed measurements acquired by the multiple sensors on the various aircraft. Traditional and high-tech