Using everything from a customized DC-8 jetliner to ground radars to 4-inch rain gauges, scientists are fanning out across one of the soggiest places in the United States this month to measure raindrops and snowflakes.
Led by NASA and the University of Washington, the field experiment on the Olympic Peninsula will try to validate, on the ground, how well global satellites measure precipitation from space, which is crucial for areas of the world that lack rain gauges or other equipment.
That’ll be helpful for years to come in helping scientists craft better models to predict a range of phenomena, from the intensity of weather events to the likelihood of a snowpack accumulating.
“If everything goes right, generations of students will use this data,” said Simone Tanelli, a radar scientist from NASA’s Jet Propulsion Laboratory who will be gathering data from the air.
The four-month Olympex project will collect detailed atmospheric data — right down to the size of raindrops — over the ocean, along the coast, in the foothills and across the rugged Olympic Mountains.
Ground instruments already have started collecting data.
And this week, NASA’s DC-8, a flying science laboratory, touched down at what will be its home base for the exercise — Joint Base Lewis-McChord.
It’s one of three aircraft equipped with special radars and other devices that will gather information to create a three-dimensional view of weather events over the next six weeks. Two of them will fly out of JBLM.
Tanelli gave a tour of the DC-8 on Wednesday. It contains several work stations where up to 10 scientists can watch data roll in instantaneously. On past experiments, the aircraft has held more than 50 scientists.
The plane’s guts are filled with sophisticated equipment that can scan precipitation in layers, from the plane’s altitude at 35,000 feet all the way down to the ground.
Another device equipped with a parachute can be ejected from the DC-8, gathering data as it slowly drops to the ocean.
The idea is “to connect the dots between what we’re seeing on the surface and what we’re seeing from space and what we’re seeing in the clouds,” said Walt Petersen, NASA’s deputy project scientist for ground validation.
Specifically, the scientists are making sure that global measurements made by a group of satellites are accurate. Those satellites are part of a joint mission of NASA and the Japan Aerospace Exploration Agency that launched last year.
“There are a lot of parts in the globe where there are no weather radars and no capability to put radars or a rain gauge in,” Petersen said, adding that such places rely on satellite weather forecasting.
Those satellites need to be able to accurately detect heavy tropical rain, light snowfall and other forms of precipitation. Such information would improve forecasting for floods and droughts as well as management of water resources.
The Olympic Peninsula, home to a protected temperate rain forest, is ideal for the project because it’s in the middle of an active winter storm track, said Lynn McMurdie, a UW researcher and one of the project’s lead scientists.
It’s reliably wet on the peninsula, where the annual precipitation ranges from more than 8 feet of rain on the coast to about 15 feet of snow in the mountains. The landscape changes from sea level to more than 6,500 feet in a short distance of about 30 miles, offering a comprehensive picture of how precipitation falls over such extreme differences in terrain.
The scientists are deploying an arsenal of equipment at all levels, including a high-altitude aircraft, a variety of radars, a network of tipping bucket rain gauges and remote cameras that will provide images of snow stake measurements in higher elevations.
“We’re looking at everything from above the clouds down to the ground in the river valleys,” said Robert Houze, a UW professor of atmospheric sciences and principal investigator.
While there have been other field campaigns, “none has ever been attempted in such rugged, complex terrain where it’s very difficult to set up measurements on the ground to go with the ones from the airplanes,” Houze added.
The end result is to get a better way to predict precipitation around the globe, Petersen said.
Partners involved in the project include the Quinault Indian Nation, Environment Canada, the National Park Service and the U.S. Forest Service.
“We’re rooting for the rainy weather. We’re excited, and we’re a little nervous,” Houze said. “Even after years of preparing, you’re still dependent on nature giving us what we want to look at.”
The experiment comes at a busy time for McChord Air Field. It’s hosting its usual fleet of about 40 C-17 Globemaster III cargo jets that fly military support missions around the world.
It’s also taking part in the Air Force’s testing of a next-generation refueling tanker that Boeing is developing south of Seattle. That assignment has F-16 fighter jets and older refueling tankers flying out of McChord.
And now it’s sharing in the weather experiment by giving ramp space to the NASA DC-8 and a separate high-altitude aircraft called an ER-2 that also will gather precipitation data.
“It’s going very well,” said Col. Tony Clavenna, the commander of the maintenance group for the 62nd Airlift Wing. “We’ve got a good amount of ramp space. It’s really neat to have the rest of the team here.”