CU Geology Professor Eric Small

Professor Small treks into the classroom, handing out the daily class exercise labeled Pleistocene Glaciers to the front row of students. He pulls out a flyer as he gets to the center of the room, and tells the class “This morning I got this on my door.” The front of the flyer reads Global Warming: Crisis, or Delusion?” The classroom, full of students majoring in Geology, bursts out in laughter as Small grins.

Eric Small is a Professor of Geology at the University of Colorado Boulder. At the same time, Small has his own research group, and has many ongoing projects with other scientists and graduate students alike. One of these award-winning projects is a study in the development of GPS for monitoring the water cycle on Earth.

The topic for the day’s class discussion is land ice, meaning glaciers and ice sheets. As he reviews to the class how we know the changes in land ice coverage from the past, Small notes for us to pay attention to how this relates to the flyer he showed earlier. The key point is, land ice would advance and retract on a yearly basis and long-term basis. With all of the information collected, the class sees how humans have affected both long-term and short-term glacial change.

GPS Interferometric Reflectometry, (GPS-IR) is a technique discovered by Small and three other researchers. This method uses current Global Positioning Systems to figure out important water resource information. The team noticed that, by measuring specular reflections of signals sent to GPS units from satellites, they could calculate changes in snow cover, glacier and ice sheet thickness, soil moisture, and even water content in vegetation.

As class ends, Small agrees to discuss his research and how it relates to our class. As a hydrologist and climate specialist, he exhibits to our class how important water and snow are to our environment, and describes how different changes in climate can attribute to loss or gain of land ice and soil moisture.

The information collected from GPS-IR can tell us important information about current water resources. It will allow communities to know how much snow has accumulated in a certain area near a GPS site, which allows us to calculate how much melt to expect during a wet season. Also, because soil moisture can also cause a reflection interference pattern in the GPS signal, it allows us to calculate how dry or wet the soil in an area is. This information is vital in knowing what water resources exist.

Small sits at his desk, preparing to post the notes from lecture onto the class website. He removes his blue sweater he had previously been wearing, to reveal a plain grey t-shirt. As we discuss how the team discovered this technique, he looks up from his computer. “It was just an accident” he says. “The person who I work with, Kristine (Larson), says ‘Look at this funny signal, it changed on this day when it rained. I think i’m measuring rainfall.’ But it stayed high for five days afterwards, so it’s not the rain, it’s the soil moisture. And we can measure soil moisture and compare that to the GPS signal to confirm that’s the case.”

But science comes at a cost, right? And in order to get the money needed, they must continuously prove their research is important. “It basically costs $100 thousand a year to pay a graduate student and one third of my research time, and to put the lights on in the building, because CU puts overhead on it. So, we’ve probably spent $3 million on government money on the project. But to get that money, you need to write proposals, so part of my job is to make sure there’s money.” Small says. “I’ve calculated that basically fifty people-years have been spent on this project.” That’s a small amount of money when you think about how much time it has afforded.

GPS-IR currently only uses one GPS network, called the PBO or Plate Boundary Observatory network. It is very inexpensive to bring the technology needed for this technique into all GPS sites around the world, which would allow for much more information to be collected.

When looking to receive grants, a team must prove their cost-effectiveness. “Part of the reason why the government is interested in paying for it is because they spent a couple hundred million dollars putting in these GPS networks, completely for studying earthquakes and plate deformation. So now, it’s like, is it worth another $2 million to get double the value of your network? Yeah, we’d be fools not to get more out of it if we can.”

Water resources are a growing concern today, as many communities worldwide are facing issues like droughts and floods. In Colorado, water and snow are current hot issues. On an almost-yearly basis, the state faces problems relating to water. Some years are extremely dry, and there can be many wildfires; however some years, like the Fall 2013 flood, there can be an unexpected, extreme amount of water, resulting in destruction. The knowledge gained from GPS-IR will help us know what’s going on with water resources, before they become an issue.

As more information is received worldwide, we find ways to be smarter about our water use, and make sure important resources aren’t used up. The team currently puts all of the data collected on an open portal, so that anybody can use the information. The importance of information can not be overrated, and as this technology spreads into other GPS networks, its influence will as well.


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