Posts Tagged ‘GPS’

Scientists use underwater robots to excite students about science

March 3, 2014

Can underwater robots catch the imagination of middle and high school students and spark an interest in science, technology, engineering and mathematics? Researchers and educators from the University of Georgia’s Skidaway Institute of Oceanography and Marine Extension (MAREX) think so. They are creating an education program focused on autonomous underwater vehicles (AUVs), also called gliders or underwater robots.

The program, “Choose Your Own Adventure,” will capitalize on Skidaway Institute’s expertise with AUVs and MAREX’s extensive history of marine education. Skidaway Institute scientist and UGA faculty member Catherine Edwards, and MAREX faculty members Mary Sweeney-Reeves and Mare Timmons will direct the one-year project.

Catherine Edwards (center) demonstrates an AUV to Mary Sweeney-Reeves (left) and Mare Timmons.

Catherine Edwards (center) demonstrates an AUV to Mary Sweeney-Reeves (left) and Mare Timmons.

The AUVs are a cutting-edge technology in marine research. The torpedo-shaped vehicles can be equipped with sensors and recorders to collect observations under all conditions. They are launched into the ocean and move through the water by adjusting their buoyancy and pitch. Because they are highly energy-efficient, gliders can remain on a mission for weeks at a time. Every four to six hours over their mission, they surface, report their data by satellite phone and receive instructions as needed.

Skidaway Institute’s AUV, nicknamed “Modena,” has been used in several recent projects, including “Gliderpalooza,” a simultaneous, cooperative launch of 13 AUVs from different institutions in 2013.

“Gliders are education-friendly, but the existing outreach activities are stale,” said Edwards. “Our program will develop the next generation of AUV outreach programs by combining cutting-edge, interdisciplinary research with educational activities and strong STEM components.”

The proposed work will highlight the problem of working with the strong tides that are characteristic of the Georgia coast. A big issue in operating gliders there is developing a guidance and navigation system that will function well in that kind of environment. The fast-moving Gulf Stream, located roughly 100 miles off the Georgia beaches, also introduces navigation problems.

“Although the AUVs have Global Positioning Systems and can be programmed to travel a set course, tidal and Gulf Stream currents can exceed the glider’s forward speed, which can take the instrument off course and keep us from collecting data where we need it,” Edwards said.

However, on the education side, the predictability of tides makes the proposed program highly intuitive and education-friendly.

“Students who grow up and live on the water already have an intuitive sense of tidal currents,” said Timmons. “Students understand why currents change during certain phases of the moon. This coastal intuition will provide a foundation for us to start an innovative, hands-on approach to STEM activities.”

Activities will depend on grade level so middle school students will have different objectives than those in high school. However, all the activities will address the direction and speed the AUV travels to a destination. The AUV direction and speed will depend on the sea state of coastal waters such as strong currents, storms or high winds.

To address the problem of strong tides, Edwards and a team of Georgia Tech graduate students, co-advised by Fumin Zhang, have developed the Glider Environmental Network Information System, called GENIoS, which optimizes a glider’s path based on data from real-time observations and ocean models. Current doctoral students Dongsik Chang and Sungjin Cho are working to upgrade the system to integrate real-time maps of surface currents measured by Skidaway Institute radar systems.

The education plan is to involve two local educators, April Meeks and Ben Wells, who teach in the Savannah-Chatham County Public School System. Since the activities are multidisciplinary, their expertise in building math curriculum will be valuable as the team integrates concepts of marine science, math and engineering into classroom activities.

“After the initial planning phase, we will be taking the program on the road to Chatham County schools,” said Sweeney-Reeves.

Activities will include student role-playing as an AUV maneuvers through a playing field of vector currents on a large game board. Successful arrival at their destination depends on how the individual pilot responds to currents, wind and density changes in route.

“The real fun will begin when obstacles, like underwater volcanoes, a giant squid or other surprises, cause the pilot to reroute the course of the AUV,” said Sweeney-Reeves.

The activities will allow students to develop analytical skills in a program that will be compliant with Next Generation Science Standards for the 21st Century in the common core state curriculum.

The funded study will include two short glider deployments. A summer 2014 deployment will be used for field-testing, software validation and developing real-world scenarios for the outreach program. A fall deployment will serve as an opportunity for classroom participants to communicate with the glider in real time.

“We hope this one-year program will serve as a springboard for future funding and continued joint outreach by Skidaway Institute and Marine Extension,” said Edwards. “We’d love to develop computer games and apps for tablets and mobile phones that let students fly gliders through even more realistic scenarios based on the measurements we collect in real time.”

The program is being funded through a joint grant from Skidaway Institute, UGA Public Service and Outreach, and the UGA President’s Venture Fund. The UGA President’s Venture Fund is intended to assist with significant funding challenges or opportunities. The fund also supports small programs and projects in amounts typically ranging from $500 to $5,000.

For additional information, contact Catherine Edwards at 912-598-2471 or catherine.edwards@skio.uga.edu; Mary Sweeney-Reeves at 912-598-2350 or msweeney@uga.edu; or Maryellen Timmons at 912-598-2353 or mare@uga.edu.

 

UGA Skidaway Institute participates in Gliderpalooza 2013

September 18, 2013

More than a dozen underwater robotic vehicles called “gliders” will be launched simultaneously this month in a massive, cooperative project involving 10 east coast research institutions, including the University of Georgia Skidaway Institute of Oceanography. Dubbed Gliderpalooza 2013, the fleet of gliders will cruise the waters of the east coast for several weeks, collecting data that could help improve future hurricane forecasts. 

UGA Skidaway Institute scientist Catherine Edwards makes adjustments to the glider “Modena” while R/V Savannah crewman Mickey Baxley assists.

UGA Skidaway Institute scientist Catherine Edwards makes adjustments to the glider “Modena” while R/V Savannah crewman Mickey Baxley assists.

The gliders are torpedo-shaped vehicles, equipped with sensors and recorders to collect observations under all conditions. These autonomous underwater vehicles, or AUVs, move through the water by adjusting their buoyancy and pitch. Because they are highly energy efficient, gliders can remain on a mission for weeks at a time. Every 4 to 6 hours over their mission, they surface, report their data by satellite phone and receive instructions as needed.

According to Skidaway Institute scientist Catherine Edwards, one goal of Gliderpalooza 2013 is to test the feasibility of using a fleet of gliders to work together and to integrate their data—collected in the same time period, but over a wide geographical range.

“Gliders are powerful tools for oceanographers,” Edwards said. “We believe there is great potential to expand the value of them by working together on the deployments and integrating the data each collects.”

Another reason for promoting the use of gliders is their relatively inexpensive cost of operation. Gliders can operate for weeks at a time and in all kinds of weather conditions for a small fraction of the daily coast of an ocean-going research vessel.

“Gliders will never replace ships in oceanography—ship surveys are often the best way to collect data,” Edwards said. “But AUVs require far fewer resources and personnel than shipboard work, and can operate in conditions that would be impossible for traditional ship surveys. For lengthy data-collection missions, a glider can operate for pennies on the dollar by comparison.”

Scientists at Rutgers University are coordinating the project. Computers there will gather the data from the various glider groups, and make it available through a data assembly center for access to and visualization of the data in real time. Glider groups participating in Gliderpalooza will contribute pictures, updates and other notes of interest to scientists and the general public on a blog available at http://maracoos.org/blogs/main/

September was chosen as the month for deployment because many important fish species migrate in that month, and a coordinated experiment can provide a more complete picture of oceanographic conditions and fish populations. September is the most active month for hurricanes, and there is interest in the use of gliders to better understand the effects of major storms on the mixing and transport of heat, nutrients and material.

The Skidaway Institute glider, nicknamed “Modena,” and several others will also be equipped with a special instrument to monitor fish migration. In order to track fish migration, some fisheries biologists tag fish with an acoustic transmitter. The tag-transmitter sends out a sound signal identifying the fish. Typically, receivers on buoys and other stationary platforms monitor these signals. This will be the first time a fleet of moving gliders will be used to monitor fish migration.

Gliderpalooza will also serve as a field test of a new glider navigation system developed by Georgia Tech graduate students, Dongsik Chang, Klimka Szwaykowska and Sungjin Cho, who are supervised by Edwards and Georgia Tech collaborator Fumin Zhang.

Catherine Edwards works on Modena with her team of grad students.

Catherine Edwards works on Modena with her team of grad students.

Gliders can only receive GPS information at the surface. They navigate underwater by dead reckoning, using information on ocean currents from the last leg of their mission. However, the strong tidal currents on the Georgia shelf, combined with the fast-moving Gulf Stream at the shelf edge often exceed a glider’s forward speed. This creates the opportunity for significant navigational errors.

The Glider Environmental Network Information System (GENIoS) is an automated system that optimizes glider navigation based on real time data from ocean models, high frequency radar and measurements from the glider itself. By integrating these data with ocean models, GENIoS provides a more accurate prediction of the currents the glider will navigate through, and chooses the most efficient target waypoints for the glider to aim for as those currents change in space and time.   

During Gliderpalooza, the Skidaway Institute glider will conduct a triangle-shaped mission that includes one leg along the edge of the continental shelf, which also corresponds roughly to the western edge of the Gulf Stream.

“The combination of strong tidal currents and the influence of the Gulf Stream will serve as a strong test of the system,” Edwards said.

The collected glider data will go through NOAA’s National Data Buoy Center to the National Weather Service, the U.S. Navy and other data users for modeling. Data from the glider missions will also be public and available on the Integrated Ocean Observing System Glider Asset Map and at http://www.ndbc.noaa.gov/gliders.pahp.

Funding for Modena’s mission is provided by the UGA Skidaway Institute of Oceanography and the Southeast Coastal Ocean Observing Regional Association.

More information and an ongoing update on the progress of the project are available on the Gliderpalooza 2013 blog at http://maracoos.org/blogs/main/?p=448.

Skidaway Institute scientists study Intracoastal Waterway erosion

November 17, 2011

The banks of the Atlantic Intracoastal Waterway (AIWW), an artificial channel running through Georgia’s marshes behind the barrier islands, are steadily eroding, and there are several possible causes, including wakes from recreational boats. That is the conclusion of a year-long study by scientists at the Skidaway Institute of Oceanography.

 “Our goal was to quantify the impact that waves are having on the Georgia segment of the AIWW,” said Skidaway Institute professor Clark Alexander. “We also wanted to see if the salt marshes that line much of the waterway were expanding or retreating.”

Georgia contains more than one third of the salt marsh on the eastern coast of the United States and more than 90 percent of its AIWW shoreline is salt marsh. These marshes are essential habitat for fish and crustaceans because they play an important role in the life cycle of most local commercial and recreational species. The AIWW was designed to support both recreational and commercial vessel traffic.

“The major environmental impact of boats on the estuarine environment is the erosion of the channel margins from wakes,” said Alexander. “In Georgia, this diminishes the extent of the salt marsh habitat and causes the channels to widen – in some cases, at rates of up to half meter a year, which is pretty significant.”

Wakes undercut the marsh, causing to them to fail and collapse, particularly at low and mid-tides. Frequently, intertidal oyster bars are buried by eroded sediment, and oyster larvae are hindered from settling because shell material is not available upon which to settle.

Erosion is a natural process in salt marshes. However, in a natural setting, when one side of a tidal creek erodes, the other side usually accretes. Along the AIWW this was typically not the case. Alexander found extensive stretches where the shoreline was eroding on both sides of the channel.

Alexander and his team used historic and recent charts and aerial photography to track the erosion and accretion along the entire 91 mile length of the waterway between South Carolina to Florida. They also used a combination of high-definition video camera connected to a Global Positioning System (GPS) receiver to document both sides of the waterway along its length.

The research team examined shoreline change over two time periods, the first from 1933 to 1976 and the second from 1976 to 2004. The team limited their study to the eight relatively narrow main sections and six alternative sections of the waterway, avoiding the sounds where wind and storm waves might have a significant impact on shoreline change.

“Erosion has become increasingly significant and widespread in the 1976  -2002 time period,” Alexander said. “That isn’t to say that every section is eroding, but most of them are.”

Comparing the earlier time period to the later, the study found a strong trend towards more erosion in the more recent time period. Boat traffic and their wakes provide a mechanism for bank erosion.

“We don’t see commercial boating as being significant because the number of ships and tonnage in the AIWW has gone down by about 80 per cent in the past 18 years,” said Alexander. “But recreational boat registrations in coastal counties (currently about 29,000) have continued to increase.”

Alexander also has another explanation that cannot be ruled out with current information. Except for two short segments, the Corps of Engineers is no longer dredging the AIWW to maintain its target depth and sea level is rising at about 1 foot per century.  The channel could be widening because it is becoming shallower but must still transport and contain the same amount of water.  “Boating is most likely the immediate primary erosion force, but rearrangement of the channel cross section may contribute as well,” he said. “We just don’t know absolutely at this time.”

Erosion threatens Coastal Georgia archaeological sites

August 1, 2011

Along the Savannah River in Chatham County are the remains of a large, complex, former rice plantation. Archaeologists may be able to learn much about the life of Georgia’s early inhabitants by studying this site, but only if they hurry. Site 9CH685, as it is known, is threatened by shoreline and tidal creek erosion – the result of the nearby river moving closer to the site every day.

Site 9CH685 is just one of 42 archaeological sites on Georgia’s back barrier islands recently studied by a team from the Skidaway Institute of Oceanography and the Georgia Department of Natural Resources (DNR) Historic Preservation Division. The sites include a range of types, from Native American shell middens to colonial cemeteries and Civil War artillery batteries. The team spent two years studying the erosion and accretion patterns near each site to assist DNR in prioritizing the sites that require the most immediate attention. Funding for the project came from the Georgia Coastal Zone Management Program.

“The Georgia coast is constantly evolving,” said Clark Alexander, the Skidaway Institute scientist who directed the project. “During the past 150 years, the shoreline has moved more than a hundred meters along many parts of the Georgia coast.  The natural forces of wind and water have formed and changed the shape of our coastline over the centuries and continue to do so.”

Typically it is not feasible to preserve sites against these forces, so it is critical to document the sites before they are lost if there is any hope to record the history contained within them.

“Once an archaeological site has been eroded away, it cannot be replaced and the information it contained is lost forever, said Chris McCabe,  deputy state archaeologist for the Georgia Department of Natural Resources (DNR). “The loss of archaeological information to natural processes in our dynamic coastal setting is an ongoing issue for us.”

The team used a combination of current shoreline measurements near the known sites, combined with historical shoreline information from aerial photographs, charts and maps, some dating back to the mid-19th century.

Skidaway Institute's Claudia Venhern uses a highly accurate GPS instrument to record the shoreline of a Georgia coastal island.

It was Skidaway Institute researcher Claudia Venherm’s job to survey the current shoreline. Using an extremely precise GPS receiver, she walked the shorelines measuring the exact location of the high water mark within a few inches. Later, she mapped the shoreline and compared it with the historic data for the same location to determine how fast the shoreline is changing.

“We can use Geographic Information System (GIS) technology to overlay the location of the current shoreline with the shorelines from older photos and maps and obtain a very good picture of what is happening to any piece of coast,” Venherm said.

All the sites were examined to determine which were in the most danger of loss to erosion. The projected life of each site was calculated as the number of years until erosion would destroy the entire site.

Six sites had already been lost to erosion by the time the team visited the coordinates for these sites. Four more sites were still present, but are completely or almost completely submerged at all stages of the tide. The team determined 21 of the sites were eroding, and three of those have a projected life of less than 50 years.

“This study will be a big help to us,” said McCabe. “We can’t stop the erosion, but we can prioritize our work, and maximize the amount of cultural information we obtain before a site is lost.”

That rice plantation site has already yielded clues about the early Georgia economy. The tidal creek threatening the main site has produced several surface artifacts from the late 19th and early 20th centuries. A section of whiteware dinner plate etched with the name “Greenwood China Company”, which designed dinnerware specifically for use aboard coastal steamboats, was found in the creek bed.

“This artifact suggests that materials from maritime vessels had found their way to a group of individuals living at the plantation,” said McCabe. “In addition, an aqua colored bottle embossed with the name ‘Packard & James New York’ was found.”

This merchant firm distributed spices and coffee at the end of the 19th century, and its discovery at a Savannah River site hints at important turn-of-the-century maritime sail and steam trading networks.

These glimpses into the past are fleeting however, as time and tide erase these ephemeral fragments of history.  This study provides the data that the DNR needs to save as much of Georgia’s rich coastal history as possible.

1991 tritium release prompts current salt marsh research

April 14, 2010

A release of radioactive cooling water from the Savannah River Site near Aiken, S.C. provided the spark for a current research project at Skidaway Institute of Oceanography. The object of the study is to test a mathematical model that can be used to predict the way particular salt marshes may interact with future spills of radioactive water or other contaminants.

The story began in December 1991, when the Savannah River Site accidentally released nuclear reactor cooling water containing a radioactive isotope of hydrogen called tritium. Scientists followed the slug of radioactive water as it traveled downstream to the salt marshes near Savannah, where the tritium became affected by the tides. Initially, they found what they expected. Sensors in tidal creeks detected the tritium as high tides pushed it into the marshes, and at low tide it was diminished. After a few days, most of the radioactive water had moved on out to sea. The sensors still detected tritium, but the cycle was reversed. They detected very little on the incoming tide, but higher levels on the outgoing flows.

“What was happening was something we really hadn’t thought too much about before this,” said Skidaway Institute researcher Jack Blanton. “It turns out the salt marshes had absorbed a portion of the tritium.

“After the main body of the radioactive water had moved on, the salt marshes were releasing the tritium they had absorbed, and we were detecting it on the outgoing tide.”

Blanton compared the process to a soapy sponge that must be rinsed and squeezed several times to get all the soap out.

“The pumping of water in and out by the tide was causing the rinsing and squeezing,” he said.

This discovery motivated Blanton and other scientists to explore how efficiently a marsh can detain a tracer like tritium, a pollutant from a treatment plant or any other substance.

The 3-year project is sponsored by the Department of Energy through a subcontract with the Savannah River National Laboratory (SRNL) and is directed by Blanton and fellow Skidaway Institute scientist Clark Alexander, along with Al Garrett, Jim Bollinger and David Hayes from the SRNL, and Raymond Torres from the University of South Carolina.

The SRNL built a mathematical model to be used to predict this process. The idea is that the model could be applied to any salt marsh area in the world to predict how it would react to the influx of a pollutant.

The key to testing the model is to have accurate and highly detailed data regarding the morphology of the marsh.

Mike Robinson uses a specially designed small boat with GPS and sonar to survey the Groves Creek marsh.

That includes both the topographical (above the water) and bathymetric (below the water) profile of the intertidal marsh and tidal creeks at high and low tide. The scientists selected the salt marshes around Groves Creek, adjacent to the Skidaway campus, for the test. Under Alexander’s guidance, research associate Mike Robinson has been using highly sophisticated GPS equipment to develop an elevation profile of the marsh’s high ground and tidal platforms, and a combination of GPS and sonar equipment to create a bathymetric profile of the creeks and waterways.

A survey vessel from Coastal Carolina University (CCU) was used to survey the larger creeks in the study area. The crew was lead by Dr. Rich Viso of CCU.

The researchers will dump dye into Groves Creek to observe how the marsh imports and releases the dye over a several-day period. This information will be compared to predictions calculated by the model to determine how well it simulates reality.

“The problem is that if you have a spill in some other area of the world, you probably aren’t going to have the kind of detailed information we have for Groves Creek,” said Alexander.

After testing the model with the detailed Groves Creek’s profile, the model will be run multiple times while reducing the accuracy of the profile data.

“Starting with the best morphology data available, we can degrade it and see how that changes the model results,” said Blanton. “Then we can see how well the model will work to predict flow patterns and marsh flushing in an area where we don’t know all the exact details.”

Blanton and Alexander plan to complete the study by mid-2012. If verified, the model could then be used to predict the way salt marshes anywhere in the world may be affected by a contaminant spill.

Nice newspaper article

November 24, 2009

Mike Sullivan writes:

Several of us spent most of last Friday taking a boat trip to one of Georgia’s undeveloped coastal islands

Capt. Jay Fripp and Claudia Venherm

and stomping around looking for archaeological sites that may be threatened by erosion.

Claudia Venherm using a precise GPS to map the shoreline.

It is a joint project with Chris McCabe, the Georgia DNR archaeologist who is stationed on our campus.

Chris and Mary

Mary Landers from the Savannah Morning News came along and wrote a very nice story on the excursion, which can be seen here.