H2O Radio

Making Waves: Science, Research, and Technology About Water

"Dust Up: The Growing Problem Affecting Snowpack and Water Supply"[ Show/Hide Article ]

                                    Mountain snowfall around the globe is an important source of water. In the spring it melts and flows into rivers and reservoirs for cities and farms to use. But there’s been a growing problem that’s sweeping in and causing snowpack worldwide to melt faster.

"It looks apocalyptic," says Jeff Deems, a research scientist at the University of Colorado. With "a big orange-red sky, it really does look Martian."

He’s describing dust storms—layers of windblown particles that are landing on mountain peaks and leaving them coated with a dark layer of sand and soot. As anyone who has sat in a car with black upholstery on hot summer day will attest, black objects absorb more heat than lighter ones, so by the darkening the snow, it’s melting it faster.

Deems explains that "If you put dust on the snowpack, which enhances the absorption of that solar radiation, then that just pushes on the gas pedal for snowmelt." In a recent study looking at the Rocky Mountains of Colorado, Deems and lead author Tom Painter of NASA found that the amount of dust on mountain snowpack will control how fast rivers rise in the spring regardless of air temperature. And the more dust there is, the faster the runoff.

Deems_SenatorBeckBasin_dust_sampling_ChrisLandry_AndrewTemple_May2010_web The particles are carried to the Rockies by winds coming from the Southwest when deserts are drying out. The dust events are frequently on the leading edge of a storm and can be pretty dramatic—closing interstates and making it hard to see and breathe. The dust will get deposited in the mountains and quickly become buried by fresh snow, but Deems explains that the sun can see through about a foot of snow, so if it’s greater than 12 inches (30 cm) of new snow, then that dust is just buried, lurking in there waiting for the melt season to arrive.

The dust storms mostly happen in the spring, so the particulates tend to be near the surface of the snowpack and are deposited in a series of layers. Once the runoff season starts, the snow will melt down and then hit a layer of the dust. The water will drain away, but the dust piles up making the surface darker and darker as each layer is revealed. This darkening supercharges the melting, and the pattern continues until the snowpack is gone.

The problem is getting worse because there’s more dust than there used to be because of less rain with a warming climate and more land development that’s exposing bare soil. Those soil surfaces are naturally armored by crust—lichen and moss combinations that make this black armored surface. Those crusts are virtually impervious to wind erosion. They’re very strong—except when they’re crushed. Beginning back in the mid-to-late 1800s, soil started getting disturbed by people grazing animals.

Since then, Deems says, we’ve got a wide array of disturbance agents—recreational activities, oil and gas exploration and development, suburban development, dry land farming, etc. All of these activities disturb the soil crust and make the fine grain substrates available for wind transport.

And there are various climate change components. As we continue in this warming and drying trajectory in the Southwest, plants that might have anchored the soil are less likely to get the water they need to germinate and grow.

But the study doesn't suggest that air temperature can be ignored. It contributes somewhat, but Deems says their research finds that dust is the dominant force shaping the pace of spring runoff. Also, temperature does control whether precipitation falls as snow or rain, so ultimately it regulates how much snow there is to melt.

All of this has important implications for water managers. The snowpack is Colorado’s biggest reservoir, holding way more water than surface storage. If it runs off faster, it can be a challenge to store it all. And, in order to have water available for later in the summer, it’s vital that the snowpack stick around for as long as possible.

Water managers watch spring runoff to decide when—and how much—water to allocate to users, to store or to release from dams. Deems says that if we shorten the snowmelt period by increasing that rate, they’ll have a much narrower window of time over which to make those decisions.

So, what can be done about the dust? Studies have shown the soil crusts can regenerate if left alone, but land use development along with drier conditions because of climate change, could make that recovery tougher.

The report was published in the journal Geophysical Research Letters. 💧

Published 27 January 2018 | © H2O Media, Ltd.

Past Science Stories

"What Goes Up, Tells Us What Will Come Down" [ Show/Hide Article ]

What are your plans this weekend? Thinking about playing golf, having a picnic, or gardening? Before you head out you’ll probably want to check the local forecast, because when it comes to early summer weather in Denver—anything goes. It could be 80 degrees—or it could snow. How do forecasters keep up?

Of course they look at satellite data, but one of the most vital tools they use may surprise you.

PreparetoLaunch In a building near Denver’s old Stapleton Airport, Chris O’Brien is about to do his second launch of the day. After taking a few quick strides in an open field he releases a large tan balloon into the air for the National Weather Service. The helium-filled orb will drift 20 miles into the stratosphere sending back crucial data every second that it rises.

Gradually reduced air pressure will expand the five-foot-wide balloon to the size of a two-car garage. Eventually it stretches beyond its limits and pops. That releases the "radiosonde," which floats down on a little parachute.

The radiosonde is the instrument dangling beneath the balloon taking measurements on temperature, humidity, air pressure, and wind speed. Once the balloon pops it will stop recording and, in this case, will probably end up somewhere far east of Denver. It’s perfectly harmless, lightweight, and has a friendly message to return it to the National Weather Service if the little box and its orange parachute land in a yard.

LaunchTime It’s a beautiful, cloudless day when O’Brien let's go of the balloon, and you can actually see it even though it’s now easily thousands of feet up. He says if the sun’s hitting it, it lights it up, making it appear as a little white dot. It's understandable why people might mistake it for a UFO because you see a white dot high in the sky and not moving around. And then when it pops, there’s a poof just like a science fiction effect of something going into hyperspace.

It’s not every release that O’Brien gets such ideal conditions. He launches twice a day—once in the early morning darkness and again in the late afternoon—no matter what the weather. He sends up balloons in blizzards, rain, or hail. The only time he’s forbidden to launch is when there’s lightning in the area. Think Ben Franklin and his kite. So how do meteorologists use the data and why can’t they just use satellites? After all, it is 2017.

Weather balloons are the backbone for weather data and modeling in the country, according to Chris Spears, self-described weather nerd and storm chaser for Denver’s CBS 4. So why do forecasters still use balloons to collect data?

The National Weather Service sends up balloons twice a day with instruments attached measuring the atmosphere in real time from bottom to top. Spears says this provides a true snapshot of how the atmosphere is at the moment.

He explains that one example of what data balloons provide that satellites can’t are conditions during severe storms. He looks for what winds are doing from the ground up. If there’s heavy wind shear—meaning changing speed and direction as you leave the ground and go up—that means your atmosphere is rolling. And that could be the beginnings of a thunderstorm that grows into a tornado. That data would not be available without sending balloons up.

BuhBye And not only is data collected here in Colorado helpful in local forecasts, it can also tell the story for the Midwest and East Coast. In fact, sometimes the National Weather Service requests an extra launch in Denver when they’re concerned about tornadoes or maybe watching for a big East Coast snowstorm. Storm systems can go through rapid changes as they come over the Rockies. When a system comes over the Colorado mountains they may lose their identity and fall apart. Sometimes a storm crosses the Rockies, gets onto the Plains, and gains a new life heading across the rest of the nation as it continues its track along the jet stream. Colorado sometimes is candidly known as a birthplace for weather systems.

So with balloons and satellites, why is the forecast still sometimes wrong? The simple answer is, especially in Colorado, there just aren’t enough balloons to give a full picture.

Spears says it’s amazing what forecasters can do with what little data they have. In Colorado, for instance, balloons are sent up in Denver and Grand Junction. There are many miles between the two cities and a lot of terrain. So meteorologists make their best projections based on balloon and satellite data fed into computer models and then interpolate what’s happening between launch sites. But from time to time, it just doesn’t pan out.

Sometimes the reason is that no one saw something called a shortwave, which is just a tiny kink in the atmosphere. It’s a ripple, and that ripple that may have been between Denver and Grand Junction and wasn't sampled. Suddenly, as the day goes on that ripple grows. Forecasting would be improved if the Weather Service could send up balloons from every city in the U.S., but there’s just not the money to fund that.

Speaking of funding, there’s been talk in the Trump administration of cutting the budget for NOAA, which oversees the weather balloon program. What would that do to forecasting?

Spears says bluntly that if NOAA faced budget cuts the weather balloon program must be protected. If not, forecasting would go back to the way it was done in 1920s and '30s.  💧

Published 15 June 2017 | © H2O Media, Ltd.

"New Concerns About Groundwater Contamination Near Military Bases"[ Show/Hide Article ]

EST_CHiggins_PFASs_final A study out this week raises new concerns about groundwater contamination near military bases. Last year it was reported that firefighting foam used at bases contained PFCs—chemicals that have been linked to adverse health effects, including cancer.

In response, some utilities are installing granular activated carbon filters to remove two chemicals, called PFOA and PFOS, that are most often associated with the firefighting foam. But this new study found numerous other compounds are in the mix—and that the filters may not prevent them from getting into drinking water.

Christopher Higgins, associate professor of civil and environmental engineering at Colorado School of Mines, is the senior author of a paper published June 6, 2017, in Environmental Science and Technology. He said that although there's been a lot of focus on PFOS and PFOA, he and his team believed shorter chain versions of those compounds were possibly present in water supplies near bases.

After studying water near a former Air Force base, the researchers observed around 30 "PFOS-like" compounds—half of which they had only recently discovered. Because they found new chemicals, Dr. Higgins and his team wanted to know if the carbon filters being implemented by utilities would prevent the contaminants from getting into drinking water. They found that filters may remove compounds for some time, but the time it takes for that media to be exhausted, in which case you'd have to replace that carbon, is faster for some chemicals than others. In other words, granular activated carbon filters worked, but only if utilities changed them frequently.

While this may sound like more headaches for water providers already coping with the contamination, Curtis Mitchell, utilities director for the city of Fountain, near Peterson AFB in Colorado Springs, said the report’s timing is perfect because the city has not yet installed their first filtration units and is in the process of additional testing and design toward a long-term solution. Fountain is in the midst of a pilot study to determine what type of filters perform the best and then will work with the military to get at least two installed before peak summer demand. To date they've tested four different types of granular activated carbon to see how long and effective the activated carbon is.

The results of the pilot study will not only guide how Fountain filters groundwater but will be helpful to other utilities around the country also dealing with firefighting foam contamination. Which begs the question: Who’s paying for all of this?

As for Fountain, Mitchell has a reasonable expectation that if the findings show that the Air Force is the primary contributor to contamination, then the city would be able to get some sort of assistance. Determining the amount of assistance might come very soon. The Air Force has recently finished their assessment of Peterson Field's contamination, but they have not released their findings to the public. That report is due out any day.  💧

Published 6 June 2017 | © H2O Media, Ltd.

"Can a Tsunami Be Stopped in Its Tracks?" [ Show/Hide Article ]

Tsunamis happen all the time from undersea volcanoes, landslides, earthquakes—and even meteorites. Although warning systems can alert coastal residents about potential waves, just how destructive and dangerous they might be is hard to gauge. Until now, perhaps. A researcher from Cardiff University in Wales says the best way to understand a tsunami's potential impact is to "listen" to the wave itself.

In December 2004, a 9.3 magnitude earthquake struck off the coast of Indonesia, rupturing a trench in the Indian Ocean over 750 miles long. The tremor unleashed a tsunami with energy equal to several atomic bombs, and those waves raced toward coastlines at the speed of a jetliner. The wall of water eventually reached 11 countries and killed nearly 230,000 people—one of the worst natural disasters of all time. Unfortunately, there weren’t enough ways to warn coastal residents and tourists of the looming disaster, nor its gargantuan size.

050101-D-0000B-081 Right now the best predictor of tsunamis is something called "DART," for Deep-Ocean Assessment and Reporting of Tsunamis, which uses open-ocean buoys and coastal tide gauges. The network reliably detects tsunamis hours in advance and provides warning, but predicting their exact size and when they’ll occur is more challenging.

Until now perhaps. Dr. Usama Kadri, a lecturer of applied mathematics at Cardiff University, thinks the key to knowing the potential ferocity of a tsunami is to "listen," so to speak, to the wave itself.

He says when you have an event in the ocean such as a submarine earthquake, it releases a family of waves. That "family" includes the surface waves that we see, but also sound waves called "acoustic gravity waves."

According to Dr. Kadri, acoustic gravity waves travel at the speed of sound in the water, which means by the time a tsunami has traveled hundreds of kilometers, acoustic gravity waves already traveled more than a thousand. And being able to read those sound waves may give crucial extra time to evacuate areas because acoustic gravity waves carry valuable information about the properties of the earthquake and approaching tsunami, which can be employed in an early detection warning system.

Tsunamis happen all the time in the ocean and rarely result in a big monster wave as depicted in the movies. They’re actually a series of waves that can be caused by undersea volcanic eruptions, landslides, or even a meteorite plunging into the ocean. Most commonly though, tsunamis are caused by earthquakes.

And they vary greatly in size. Kadri suggests that by listening to the acoustic gravity waves with hydrophones, or underwater microphones, warning centers could read the data well in advance of the wave hitting the shoreline to know whether the tsunami will end up being a surfer’s dream—or a catastrophic nightmare.

Tsunami Warning Dr. Kadri says the technology exists and proposes a worldwide early detection system that could not only save lives, but millions of dollars in damage. But even with advance notice, once in motion, tsunamis can't be stopped. Or can they?

Kadri has done the math, and he thinks you could actually slow down or reduce an approaching tsunami by using its very own acoustic gravity waves—against it by taking the ones generated naturally by the very same earthquake, modulating them to the right resonant frequencies, amplifying them for an effective interaction, then redirecting them back to the tsunami.

Or, he says, we could "blast" the approaching tsunami with engineered acoustic gravity waves sent from the shore in order to slow them down. But Kadri is the first to say this would be an enormous engineering challenge because his calculations show the energy in the acoustic gravity wave would have to be the comparable to the tsunami, which is huge, impracticably huge.

Undeterred, his next step is to test his theory in the lab. But even if tsunami mitigation is still a dream, he’s got other potential uses for these waves. Remember we said a meteorite plunging into the ocean could generate acoustic gravity waves?

Kadri said they could be have been potentially useful in finding another object smashing into the sea—the missing Malaysia Airlines flight 370. When it hit the water, it likely created vibrations like a meteorite.

He’s not saying he can find that plane, but acoustic gravity wave theory could be a tool in future ocean impacts. Says Kadri, the ocean is a very noisy place. There are sound waves traveling all the time. And for that reason he will likely stay a very busy man. 💧

Published 15 March 2017 | © H2O Media, Ltd.

"Tea Time in the Wetlands"[ Show/Hide Article ]

What Can an Ordinary Tea Bag Tell Us About Climate Change? The Answer Could Be Steeped in Mud.

The kettle’s on the boil and we’re ready for some tea. But instead of dousing our favorite blend in hot water, a group of researchers in Australia would rather we take that tea bag and stick it in the ground—in the mud, to be precise. But don’t worry. They aren’t wanting the bags to go to waste. Burying them in places like wetlands and marshes is going to help the scientists understand how well those ecosystems store carbon. So, why tea bags?

According to Stacey Trevathan-Tackett at Deakin University in Melbourne, Australia, they're using tea because it’s in a little bag and they know how much is in there when they start, and they have standard decomposition rates. She says that if tea in the tea bag decays quickly it’s releasing more carbon dioxide into the atmosphere than if it breaks down slowly. If it decomposes more slowly, it’s storing more greenhouse gas in soils rather than letting it escape.

Blue Carbon Lab deploying tea bagsThe goal of the study is to identify wetlands around the world where decomposition rates are slower and then go and protect or restore those areas. To that end, they have people all over the planet burying tea bags in wet marshy areas and then they’ll map the data. Every few months they'll ask participants to collect some of their bags and they’ll analyze those to get an idea of what’s happening.

Most of us think of rainforests as places that absorb carbon from the atmosphere, but new research suggests that carbon stored in places like mangrove forests, tidal marshes, and wetlands—those places are twice as effective as forests in drawing carbon dioxide from the atmosphere—a process scientists call "sequestration." And the reason is because as trees and plants decay in a wetland, they generally sink underwater and eventually are covered by sediment, which limits the carbon from escaping. Although trees in a forest can harness a lot of carbon from the atmosphere to photosynthesize, when they die and decompose some of that carbon goes right back into the air.

But not every wetland is equal in its ability to sequester carbon and that’s the reason for the study. Wetlands vary according to latitude, climate, soil types, and whether they’re freshwater or saltwater.

Stacey says it’s a good opportunity to look at how all these things are affecting carbon cycling and carbon sequestration.

If we hurry. These valuable wetlands, which already provide much benefit like stabilizing shorelines and filtering water from pollutants are increasingly threatened by development. The bonus about their ability to slow climate change—it could be slipping through our fingers.

Stacey Trevathan-Tackett agrees that they're great no matter what. It’s just whether carbon sequestration can added to the list of the number of services they provide. So if you’re a professional—or citizen scientist, Stacey and her team would love your help in reading the tea leaves by putting tea bags in your local wetland. Visit their website at BlueCarbonLab.org for more information on how to sign up.  💧

Published 1 March 2017 | © H2O Media, Ltd.

Music Credits: 'Technology' by ANTARCTICBREEZE, Creative Commons  |  Masthead photo: Nick Maroulis, Creative Commons

H2O Radio
© 2018 H2O Media, Ltd. All Rights Reserved.