Science shines light on how the Smokies got their nameNASA studies precipitation in Maggie Valley
The misty fog that often covers this region is much more than just the namesake of the Great Smoky Mountains — it’s apparently a vital source of water in the Appalachians.
That’s one of the conclusions that has been drawn so far from a recent intensive study of precipitation in the area.
The project, called the Integrated Precipitation and Hydrology Experiment (IPHEX), is a field campaign led by NASA’s Global Precipitation Measurement Ground Validation Program, which aims to help scientists better understand difficult-to-predict weather patterns in North Carolina mountains.
A satellite was launched from Japan in February and is being paired with on the ground studies across Western North Carolina.
"What we're trying to do is study and learn about the precipitation from the summit to sea, how it evolves as it moves from the mountains to the plains," said Walt Petersen of NASA's Wallops Flight Facility in Virginia, who is leading the field campaign. "Then we use that information to improve satellite observations of precipitation and how those observations can best be used in applications like hydrologic models."
While looking for a good place to set up one of the ground monitoring stations, scientists stopped in Maggie Valley where they met with Neil Carpenter, who oversees the Maggie Valley Sanitary District. The team needed a safe place to set up equipment and get Internet access, and it just so happened Carpenter had the perfect place just in the backyard.
Within three days, the secure and constantly monitored space behind the sanitary district is now covered in highly specialized equipment that constantly works to measure various elements that play into cloud formation and precipitation in this region.
One of the main studies at the site is on how aerosol affects clouds and rain. According to NASA, aerosols are minute particles suspended in the atmosphere.
“You need aerosol particles in the atmosphere…it impacts everything from clouds to climate,” said Adrian Loftus, a NASA postdoctoral research fellow with Oak Ridge Associated Universities.
On a recent sunny day with little cloud cover, the team was out observing the equipment. A large trailer with a radar on top has the NASA logo plastered on the front. There are also several other pieces of equipment scattered across the grass, moving robotically while gathering information.
One set of equipment called “III Channel Microwave Radiometers” helps gather information that may help better predict flash flooding and landslide threats to the area. The radiometers measure microwave energy from the atmosphere at different frequencies and gather information about the type of precipitation in the air.
Ana Barros, a professor of engineering at Duke University, is part of the science team for NASA’s Global Precipitation Measurement Missions. Since 2007, she and her students have been placing rain gauges in difficult-to-reach places in Cataloochee and the Great Smoky Mountains National Park. There are now more than 100 sensors that will help scientists learn more about precipitation in the mountains.
The current site in Maggie Valley is being used as a prototype, Barros said.
The research so far has revealed that the way rain develops and falls in the Great Smoky Mountains is not unlike many tropical climates, such as Florida.
Annual rainfall in the Everglades is about 54 inches on average and about 50 inches in North Carolina, with about 60 inches in the Appalachian region.
“The physical processes are the same, so we can think of the mountains in the Southern Appalachian Region as an open air laboratory,” Barros said.
About 50 percent of the precipitation here is from fog, which is how the Smoky Mountains got their name.
“There’s always a little bit of fog and low level clouds and there’s always a little bit of rain going in the air,” she said.
This light rainfall from fog is related directly to the regional water cycle, which is why it’s such an important part of the project. Another interesting observation when it comes to aerosol is what happens in the mountains after it rains.
“It’s clearer after it rains. That’s because the aerosols have been washed out of the atmosphere. Right after it rained here the total number of aerosols was less than what you see over the oceans. That tells you that the air is really clean here. Once aerosols start coming back, I would guess it gets really foggy,” said Kyle Dawson, a doctorate student at NC State University who is part of the team.
Part of Dawson’s work is studying what aerosol conditions help with fog cloud formation because of it’s value to our water supply.
“It’s unique here because we have multiple cloud levels. This region depends a lot on precipitation from low-level clouds. Understanding fog will help us understand the water cycle here so it doesn’t go away in the future,” Dawson said.
By validating what the equipment on the ground sees with what the satellite sees, flood warnings could be improved as well.
Steve Nesbitt, a professor at Illinois State University, has also played a part in the study by helping launch two aircrafts with specialized equipment from the Asheville Airport to fly over the Maggie Valley site during rain and storm activity. The planes are equipped with a replica of what is installed in the satellite to help verify what the satellite is seeing, Nesbitt said.
One of the aircrafts measures the amount of water in the clouds and takes pictures of individual droplets, around a million droplets a trip.
“We can look at the same storm from different angles and with different types of sensors all at the same time,” Barros explained.
These types of studies are especially helpful to doctorate students like Dawson and Yajuan (Viola) Duan, a Duke University student who one day wants to do similar work in the Andes.
“I can use all the things I learn working on-site and apply the same technique in other places,” she said.
Not to mention, getting the chance to work as a part of a team with NASA is “awesome” in itself, she added.
Barros thanked everyone in Haywood County and beyond who have shown such support from the project including the Maggie Valley Sanitary District, Western Carolina University, Haywood Community College, University of North Carolina at Asheville and private landowners.
The scientists hope to invite local elementary schools to come take a look at the instruments that are set up before the project ends June 15.