Obstacles to determine how much water is locked up in the world's mountain snow have yet to be conquered. No single instrument, even the space-based, had ever come close to hurdle it.
Against this backdrop, NASA's SnowEx has joined the fray with a goal — to find the best snow-measuring techniques.
"This is the most comprehensive campaign we have ever done on snow," declared Edward Kim, a remote sensing scientist at NASA Goddard and the SnowEx project scientist.
Too Much Water But Too Little
Seventy percent of the world's surface is covered by water of which only 2.5 percent of this is fresh water. Of the available fresh water, more than two-thirds are locked in glaciers.
In addition, about 20 percent of the Earth's land surface is covered by snow land, which also has water locked in it.
This has far-reaching consequences on a society where more than a billion people depend largely on snow for their fresh water, Kim said.
The water locked in the world's mountain snow has other consequences for people, such as devastating floods, drought, and instability when its supply is scarce. It is said some 663 million people worldwide have no access to drinking water.
Snow packs that melt, for instance, provided a major supply to the annual streamflow in the western United States when spring and summer arrive. Yet there is no information available, at present, how much water will pour out from melting snow owing to inadequate ground measurement sites.
This situation has led to the birth of SnowEx.
Scientists and resource managers wanted to have a comprehensive view from space the amount of water contained in the snow-covered land that will eventually melt into streams, rivers, and reservoirs.
SnowEx: Multi-Year Research Campaign
The snow-covered mountains of Colorado were combed by aircraft with sensors as researchers have completed the first flights of the SnowEx campaign this month.
The NASA-led experiment uses five aircraft with 10 sensors with a goal to find the right combination to develop instruments and techniques which could be used in a snow-observing space mission in the future.
"We will also figure out a better way to optimize the use of existing satellites to make measurements," Jared Entin of the Terrestrial Hydrology Program at NASA said.
Multiple sensors are needed to address the difficulty in measuring water content in snow including those under the canopies.
"We will work closely with our ground team to try new techniques to see if we can figure out how to do that accurately," said Charles Gatebe from NASA Goddard, SnowEx deputy project scientist and senior scientist with Universities Space Research Association.
The Terrestrial Hydrology Program at NASA Headquarters in Washington, D.C. sponsored SnowEx while NASA's Goddard Space Flight Center in Greenbelt, Maryland managed the multi-year campaign.
Storage of data generated from the campaign will be at the National Snow and Ice Data Center in Boulder, Colorado and will be accessible to all.
The campaign is expected to "generate the best ideas from the global community of snow experts," Kim said.
