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How drones are advancing scientific research – Phys.Org

By Aerospace, Editor's Choice, Hydropower, News, Robotics, Sensors

Drones, or unmanned aerial vehicles (UAVs), have been around since the early 1900s. Originally used for military operations, they became more widely used after about 2010 when electronic technology got smaller, cheaper and more efficient, prices on cameras and sensors dropped, and battery power improved. Where once scientists could only observe earth from above by using manned aircraft or satellites, today they are expanding, developing and refining their research thanks to drones.

Drones can range from the size of airplanes to the size of bumblebees. They comprise part of that have a controller on the ground, and some form of wireless communication (usually radio signals) between the operator and the . Most are powered by lithium-polymer batteries, while larger ones may use airplane engines. Many drones are made of carbon fiber making them light and easy to land without disturbing the environment. The Federal Aviation Administration requires that drones remain within the operator’s line of sight; larger drones that fly longer distances must obtain more involved licenses that allow them to fly outside of the line of sight.

The Scientific Uses for Drones

Depending on their mission, drones are equipped with different payloads or equipment. Digital cameras can identify plants and animals, and help create 3-D maps. Thermal cameras detect heat from living creatures like animals or stressed plants, as well as from water. Hyperspectral imaging identifies features of plants and water through measuring reflected light and can interpret a wider range of wavelengths than the human eye can see. LiDAR, which measures how long it takes for an emitted pulse of light to reach a target and return to the sensor, can be used to calculate the distance to an object and its height, which is used for 3-D maps.

Drones monitor rivers to help predict flooding. They identify areas that are being illegally logged. They can discern the spread of algae in water bodies, as well as saltwater intrusion. They identify plant species and detect forest tree disease.

In the energy industry, drones are being used to identify methane leaks in oil and gas production, and to monitor pipelines and wind and solar installations.

Drones are tracking sea mammals, counting animal populations and monitoring enforcement in marine conservation areas. Duke University drones recently showed that gray seals are returning to the New England and Canadian coasts due to conservation efforts. Researchers at Ocean Alliance, a Massachusetts-based whale conservation organization, used drones flying low above a whale to capture spray from the creature’s blowhole. They then analyzed the collected DNA to study the whale’s microbiome, stress and pregnancy hormones. Drones are also being used to keep an eye on endangered species and to combat poachers. While protecting wildlife with drones seems like an obvious application, there has not been much research done on the actual effects of drones on wildlife. One study on bears showed that they were stressed by the presence of drones.

Some scientists from the Earth Institute’s Lamont-Doherty Earth Observatory are using drones to expand their research as never before.

Alessio Rovere, junior research group leader of the Sea Level and Coastal Changes group at MARUM (University of Bremen)/Leibniz ZMT, and adjunct research scientist at Lamont-Doherty, studies coastal erosion, mangrove communities as well as the distribution of corals and the death of shallow corals (if coral bleaching is severe, drones can see it from above). In his work around the world, he uses off-the-shelf drones whose batteries last 10 to 15 minutes. The drones take many pictures at short intervals, which are later merged through software and algorithms to construct a seamless image of the area and a 3-D digital elevation model. Because coastal areas change rapidly, repeat flights at short intervals can show differences in conditions, for example, before and after a storm.

“Drones make it easy to get a very detailed view of a small area where you want to have elevation measures,” said Rovere. “If I had to do a beach survey before I started to use drones, the typical thing to do is to put a GPS on your backpack and walk along the beach to actually measure points on the beach…Now a drone can fly above our heads, cover the same area and get much higher resolution pictures. It saves you time and allows you to gather much higher detailed data.”

For small areas, it’s a powerful tool to have, he said. For big areas, he thinks it might be more convenient to have sensors mounted on a plane or use a bigger drone that can cover more area and has a longer flight time.

LiDAR Topography Scanning

Einat Lev, a Lamont assistant research professor, studies volcanoes with the aim to improve eruption hazard assessments and predictions. She used a drone equipped with a camera to take thousands of photos of the 2014-2015 lava flow of the Holuhraun volcano in Iceland, one of the largest lava flows in recorded history. The photos are being used to create a 3-D digital topographic map of the flow. LiDAR scanned the topography of the main vent and a thermal camera recorded temperatures at cracks and hot springs. Because Lev and her colleagues visited the volcano not long after it erupted, the lava flow was still unstable and hot.

“The biggest advantage of using drones is that they can take you places that are very difficult to get to…We couldn’t map the structure of the lava flows in Iceland in the interior part of it because it was just too difficult to reach, and the drone just flies above and gets us that data,” said Lev in a video about her work.

Christopher Zappa, a Lamont associate research professor, specializes in ocean and climate physics.

In the marginalized zones (transition zones between open ocean and sea ice) of the Arctic and in the tropics, he studies how the atmosphere generates waves through wind, how waves break, and how that energy injected into the ocean affects the transfer of gases, heat and energy between the ocean and the atmosphere. Zappa uses large fixed wing drones with wingspans of 10 to 12 feet and 5 to 6-foot fuselages. These sophisticated unmanned aerial systems that can fly up to 24 hours and carry payloads of 10 lbs, require two ground crew, two flight crew and a lot of technical expertise.

Zappa developed six payloads for drones, miniaturizing technology that he previously used on ships or manned aircraft:

  • Infrared imaging tells the temperature of any surface, whether ocean, ice or land. The temperature maps help determine rates of exchange between the ocean and atmosphere; the stages of ice growth, melt or refreezing; the temperature of the meltwater relative to ocean water and how sea ice drifts.
  • Visible hyperspectral camera can show when ice breaks up and sunlight penetrates, which can influence when phytoplankton blooms occur. Since phytoplankton absorbs solar radiation, this may lead to more ocean heat close to the surface, which can affect ice melt.
  • Near infrared hyperspectral imaging shows surface properties, and can reveal the ages of sea ice.
  • Broadband long wave/short wave radiation measures how much solar energy is coming from the sun, how much is absorbed by the surface and how much is reflected back to the atmosphere.
  • Meteorological turbulent fluxes measures fluxes of momentum, heat and water vapor over the ocean. This payload also includes LiDAR which can measure ocean waves that break up the ice, and determine how much ice lies out of the water and how thick is is.
  • Drone deployed micro-drifter is a soda-can-sized pod ejected from the drone. As it falls, it analyzes the atmosphere for temperature, water vapor and pressure. In the ocean, it becomes a micro-buoy and measures the temperature and salinity of the ocean surface at different depths. The pod conveys atmospheric information in real time back to the drone where it is stored. The ocean data is kept onboard the micro-pod; once it sees the drone, it transmits the information.

Zappa is currently developing sea ice radar that will measure sea ice thickness.

“I use all these instruments in general, but we always used them from platforms that are very big and bulky [ships]. One thing drones allow us to do is get away from these superstructures that may or may not affect the environment,” said Zappa. “These UAVs [drones] allow me to get away from the ship and measure everything I want to measure in undisturbed ocean.”

“Most oceanographers never cared about the top 10 meters of the ocean where the water is going to be disturbed by the ship,” he said. “But everything I do is related to the top 10 meters of the ocean and the bottom 10 meters of the atmosphere, right where they interact. So for me, it’s critical to get away from the ship or look at areas undisturbed by the ship, both in the atmospheric side and the ocean side. Drones allow me to do this very nicely.”

Markus Hilpert, an associate professor of environmental health sciences at Columbia University’s Mailman School of Public Health, is collaborating with Lamont-Doherty on developing a drone to measure air pollution emitted by industrial smokestacks. Most air pollution data comes from ground measurements, but drones will enable the scientists to gather data about pollution at different altitudes to study how pollutants disperse in the environment. Without a drone, it would be difficult and dangerous to gather this kind of information.

At the University of Nebraska, the NIMBUS (Nebraska Intelligent MoBile Unmanned Systems) Lab is developing a variety of capabilities for drones. Prescribed fires, traditionally done by hand or helicopter, help eradicate invasive species and control wildfires by safely getting rid of excess vegetation that might otherwise catch fire. NIMBUS has developed a drone that drops ping-pong ball-sized fireball igniters. As the drone flies, the balls of ignition material are injected with alcohol then dropped to the ground. Seconds later, they burst into flames. They can be dropped in a straight line or in a particular pattern in areas that might be too dangerous or difficult to access in other ways.

 

NIMBUS has also developed drones that can measure the height of crops, which allow scientists to study crop health and reaction to environmental factors. Flying close to crops, the drone uses a 2-D laser scanner to estimate crop height. Scientists here are also developing a drone that can pick leaves off crops so that they can be analyzed for crop health or to determine the identity of a weed.

The Nebraska lab’s drone-mounted water sampling system can monitor water quality, locate toxic algae and find invasive species in hard to access areas. The drone uses a one-meter long tube to suck up water as it flies over the water body. The water is stored in vials on the drone and is measured for temperature and salinity. Some day drones could potentially carry miniaturized genetic sequencing instruments that would enable them to analyze the DNA in the samples to identify disease, and endangered or .

NIMBUS is also working on a drone that can fly to a remote sensor, determine if its battery needs to be recharged and wirelessly recharge it. Since drones could do this repeatedly, they can keep all sensors operating continuously so no data is lost. Scientists are also exploring a drone that can retrieve data from underwater ocean sensors that are able to surface.

Like the NIMBUS scientists, Zappa is a pioneer pushing the boundaries of drone capabilities. He would one day like drones to be able to fly over the ocean and measure atmospheric gases with precision. He dreams of fleets of drones with different payloads flying in formation, and he has a vision for a hybrid system combining a drone with an underwater vehicle that could fly, land on the , become a submersible and sample underwater, then surface, take off and sample the atmosphere.

Drones are constantly being improved—being made smaller, cheaper and more capable. But while they have tremendous potential for scientific research, they have some drawbacks. Smaller ones cannot fly out of the controller’s line of sight, limiting the size of the area that can be studied. Larger ones need a lot of people to run them and serious technical expertise to fly them. There is also the risk of losing a drone through accidents. And because drone use in science is still in its infancy, scientists are building the guidelines as they go, finding their way programmatically, with funding agencies and with restrictions on flying them.

“What’s beautiful about drones is they do provide a new territory for making measurements which was not possible before,” said Zappa. “But you still want to use the best possible instrument and platform for whatever experiment you’re doing…. sometimes it would be the UAV, sometimes not…You want to identify the tool that’s most useful for your science goal.”

Explore further: Chinese online retailer developing one-ton delivery drones

Flooding fight continues in parts of the Northland – Duluth News Tribune

By Editor's Choice, Engineering and construction, Hydropower, Water level monitoring

Volunteers filled and placed sandbags to protect buildings and infrastructure in Moose Lake and Hayward on Wednesday as some Northland rivers continued to rise after torrential rainfall earlier in the week.

It was a day of damage assessment and the start of cleanup in parts of the region where the 8- to 10-plus inches of rain that fell late Monday and early Tuesday caused flash flooding that receded quickly. Elsewhere, the level of rivers and lakes crept slowly upward as the day wore on.

“The lake is still rising, the river is still rising — we’re hoping that it will slow down and start heading the other direction here within the next couple of hours,” Moose Lake city administrator Tim Peterson reported late Wednesday afternoon. “There are a few homes that are starting to have water seep up through the basement.”

Community members, city workers and inmates from the state prison facilities in town helped with sandbagging efforts — something that happened four years ago, too, when floodwaters from the Moose Horn River and Moosehead Lake caused major damage in the city.

“Everybody’s a lot more prepared — everybody seems to know what could happen, how fast the water can rise, how high it can rise,” Peterson said. “People are a lot more prepared than they were in 2012.”

A top priority was protecting the city’s sewer system, Mayor Ted Shaw reported earlier Wednesday, as runoff from the north funneled into the lake and river.

“If we lose (the main pumps) that can back up into hundreds of homes and creates an immediate problem. … We’ve put sandbags in a ‘U’ around the pump house and put plastic over the sandbags,” he said.

The Minnesota Pollution Control Agency reported that untreated sewage was being discharged into the lake and river on Wednesday at an estimated 450 gallons a minute. Peterson said the release into the river was necessary to bypass the lift stations that pump sewage to Moose Lake’s wastewater treatment plant; the release eases the burden on the pumps to keep them from overheating and potentially breaking down — which would cause larger problems.

Minnesota Lt. Gov. Tina Smith visited Moose Lake on Wednesday for an update on the flooding; she also stopped in Sturgeon Lake and in Aitkin, where the Mississippi River was above flood stage but was forecast to crest a few feet lower than initially forecast. The Carlton and Aitkin county boards have declared local states of emergency, paving the way for possible assistance from the state.

In Moose Lake, the city park, campground and boat landing are closed until further notice. The Moose Horn River feeds into the Kettle River, which crested at 17.73 feet on Wednesday — not far from the record 18.22 feet set in the 2012 flood.

Willow River

Another Kettle tributary, the Willow River, was causing concern Wednesday in the city of the same name.

The Pine County Sheriff’s Office reported Wednesday afternoon that a voluntary evacuation notice had been issued for the city of Willow River amid concerns about high water at the dam in town.

County Highway 61 in Willow River was closed earlier in the day as a precaution, and the sheriff’s office and the U.S. Army Corps of Engineers were monitoring the dam.

“Water is and has been rising and flowing over the top of the dam,” the sheriff’s office reported at 4:30 p.m. “At this time the dam is holding and appears to be structurally intact. An earthen levee to either side of the dam has water flowing over the top of it.”

The sheriff’s office stressed that the evacuation notice is “strictly a voluntary measure” and included Willow River as well as areas to the south, including Rutledge.

As of 8 p.m., the sheriff’s office reported that the water level appeared to be dropping slowly, but Highway 61 remained closed.

Dam failure

There was a dam failure during the heavy rain in Washburn County. Part of the levee that held back the waters of Colton Flowage northeast of Minong gave way late Monday or early Tuesday. On Wednesday, where there once was a 47-acre reservoir, there were mudflats dotted with the stumps of trees that were inundated when the dam was built decades ago.

“There’s water running through it, but it’s no longer a lake — it’s a river,” said Joyce Palucci, who lives near the dam.

Palucci said a neighbor measured 12 inches of rain from the storms. Washouts and high water had left residents in the area with few options to drive to town, she said — and there were concerns about whether rising waters might cause more havoc.

Officials were monitoring the Totagatic River as it neared the bottom of the U.S. Highway 53 north of Minong.

To the east, sandbagging efforts were taking place in Hayward on Wednesday, along Smith Creek north of downtown, according to state officials. The Sawyer County Sheriff’s Office reported Wednesday night that U.S. Highway 63 was closed in Hayward, along with several other city streets.

Flooding damage estimates

Preliminary estimates provided by Sawyer County to the state reported $365,000 in damage to infrastructure — roads and bridges — and about $70,000 total in damage to 15 homes.

Douglas County reported about $600,000 in infrastructure damage to the state.

Countywide estimates from Bayfield, Ashland and Iron counties were not yet available on Wednesday. But the damage just at Saxon Harbor in Iron County, where floodwaters destroyed a marina and claimed a life, was estimated in the millions of dollars. The Wisconsin Department of Natural Resources has surveyed the damage at Saxon Harbor, and the U.S. Coast Guard was patrolling the area to monitor stranded and swamped boats, state officials reported. Gov. Scott Walker has toured the damage and met with local officials.

Road closures

U.S. Highway 2 remained closed between Ashland and Hurley on Wednesday; Wisconsin Emergency Management reported that the National Guard helped transport five patients by helicopter from the Bad River Reservation to a dialysis center in Ashland. Gas and electricity service to the reservation was in the process of being restored.

Other highways still closed Wednesday because of washouts included State Highway 13 between Mellen and Ashland; U.S. Highway 63 near Grand View; and State Highway 35 north of Danbury.

A new closure on Wednesday was the Highways 48/77 bridge across the St. Croix River between Hinckley and Danbury. The St. Croix River crested just shy of a record at Danbury on Wednesday, and had surpassed the record — and was still rising late Wednesday — at a river gauge near Grantsburg.

Find more closure information here.

The National Park Service closed all of its river landings along the Namekagon River, as well as the St. Croix River north of Highway 70, because of the rising water and debris.

Chequamegon-Nicolet National Forest officials reported that flooding caused significant damage to roads and facilities in parts of the forest, and the Beaver Lake Campground near Mellen and the St. Peter’s Dome-Morgan Falls area are closed until further notice.

A road and area closure is in effect for parts of the national forest west of Highway 13, north of Highway 77 and east of Highway 63. Find more information at fs.usda.gov/CNNF.

News Tribune reporter Brady Slater contributed to this report.

Surveys one element of Dam Safety program | Article | The United States Army

By Construction and Engineering, Editor's Choice, Hydropower, News, Structural monitoring

By Eileen Williamson

Dam Monitoring Survey data from the Omaha District Surveys, Mapping and Geographic Information Systems Section Field Survey team is one element of a larger Dam Safety inspection and monitoring program.

“Our Dam Safety program and supporting deformation monitoring surveys help to ensure each of the District’s 27 dams is ready to capture floodwater from the next storm,” said John Bertino, Omaha District Engineering Division Chief.

The field survey team consists of five surveyors whose services include boundary, topographic, and hydrographic surveys using the latest high tech surveying equipment and tools.

In addition to conducting surveys at military installations, for civil works water resource projects, and supporting other U.S. Army Corps of Engineers Districts, Field Survey crews perform surveys at USACE dams as part of a regular inspection and monitoring program.

Field surveyor Dave Salter uses a digital level to transfer elevations between piezometers on the downstream slope of Oahe Dam located near Pierre, South Dakota.

Field surveyor Dave Salter uses a digital level to transfer elevations between piezometers on the downstream slope of Oahe Dam located near Pierre, South Dakota.

The Omaha District is charged with operating and maintaining 27 dams within the Missouri River Basin. Among them are six large hydropower dams on the main stem of the Missouri River, and several smaller tributary dams located in Colorado, North Dakota, South Dakota and Nebraska.

There are 14 dams in Nebraska; 10 Salt Creek dams in the Lincoln area and four Papillion Creek dams in the Omaha area.

The dam safety program at each dam includes annual and five-year periodic inspection requirements. As part of the periodic inspection, Field Survey teams perform a deformation monitoring survey. Each dam has an assigned Dam Safety Engineer who is responsible for plotting the field survey results and evaluating the data against design assumptions and historical trends to ensure the continued safe operation of each project.

Field surveyors Nick Michael, Dave Salter and Michael Swinford run a level loop to establish current year elevations for tiltmeters, sensitive inclinometers designed to measure small structure changes, at Cherry Creek Dam near Denver, Colorado.

Field surveyors Nick Michael, Dave Salter and Michael Swinford run a level loop to establish current year elevations for tiltmeters, sensitive inclinometers designed to measure small structure changes, at Cherry Creek Dam near Denver, Colorado.

This process, including collecting survey data, is called a dam deformation study. Part of the dam monitoring process also requires that, whenever dam safety replacement instruments or additional instruments are installed at a dam, the team conducts a survey to provide information and document these modifications for comparison in future deformation studies.

Approximately five of the Omaha District’s 27 dams undergo periodic inspections each year. One of the dams that will soon be undergoing a periodic inspection is Salt Creek Dam Site 8 at Wagon Train Lake near Hickman, Nebraska.

One of the dams that will soon be undergoing a periodic Dam Safety Inspection is Salt Creek Dam Site #8 at Wagon Train Lake near Hickman, Nebraska

One of the dams that will soon be undergoing a periodic Dam Safety Inspection is Salt Creek Dam Site #8 at Wagon Train Lake near Hickman, Nebraska

The dam safety engineer for Salt Creek Dam Site 8 provided a survey data task list, which requires the team to survey and record five different types of data points at the dam. The data point types include vertical or horizontal movement for 15 piezometers, four slope or crest movement markers, intake structure movement markers, outlet works conduit movement points, and a centerline profile of the dam.

Each dam has a minimum of two static (non-moving) project control points. The points, placed during construction, are designed to avoid shifting or displacement. A GPS base station is set up on each of the two fixed control points, then GPS data for instrumentation, such as a piezometer, is collected. This data is compared against previous surveys to determine if there are changes in the position. The project control points are ultra-precise and have a 1/1000-inch accuracy variance vertically and approximately a 0.02 tenths of a foot accuracy horizontally.

Any indication of movement from these data points can provide an early indication of a possible issue at a dam.

“Established points could be affected by a mower or other heavy equipment so redundant measuring of each data point ensures measurements are accurate,” said Survey Crew Liaison, Danielle Campbell. “If movement or shifting is occurring, we’ll see a change when we compare multiple data points with previous years’ surveys. Movement of a single point could indicate a data collection error or damage to the point itself. But, to eliminate the possibility of a collection error, redundant measurements are taken to virtually eliminate systematic errors and make our measurements very reliable and prove, or disprove, that there is shift or damage to each respective movement point.”

“On any given day, we have crews in the field,” said Campbell. “Our annual dam safety monitoring includes surveying and analyzing established and new dam safety instruments, as well as verifying existing data points (the control points). For instance, the inspection at Wagon Train Lake required shooting 150 historically documented data points. Some of our larger projects can require collecting more than 1,000 data points.”

Measuring movement for outlet works requires confined space training and using personal protective equipment to enter the conduit and measure for movement at each joint within the conduit. “These measurements determine if the elevation between the joints of each section of conduit is higher or lower than historical measurements. In other words, they determine a comparative elevation to evaluate against historical data. With our survey methods and equipment, we can measure movement in each section of conduit and plot the movement on an X, Y, Z axis,” said Campbell.

Once all the data is collected, it is compared to previously collected data as a way to look for errors and then the survey deformation data is provided to the dam safety engineer.

“We use the survey data to analyze vertical movement (settlement) and horizontal movement of the dam and outlet works. Additionally, it allows us to understand the vertical location (elevation) of the piezometers to more accurately define groundwater levels that are recorded quarterly and during any high water event,” said Carlie Mander, the dam safety engineer who will lead dam safety efforts for the Salt Creek Dams.

Source: Surveys one element of Dam Safety program | Article | The United States Army