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KU radar research provides significant input to climate study in Nature

Thu, 01/24/2013

LAWRENCE — A collection of breakthrough discoveries that provide new details on changes in the Earth’s climate from more than 100,000 years ago — made possible in part by a team of researchers from the University of Kansas — is featured in the most recent issue of one of the world’s most prestigious scientific journals.

The Jan. 24 issue of Nature contains an article on the findings from a deep ice core drilled in northern Greenland, at a camp known as the North Greenland Eemian Ice (NEEM) drilling camp. Research at the drill site is led by the Center for Ice and Climate at the University of Copenhagen, which partners with the KU-led Center for Remote Sensing of Ice Sheets (CReSIS).

“It’s great that this paper got accepted in such a prestigious publication,” said Dorthe Dahl-Jensen, leader of the Center for Ice and Climate. “It shows what a great team of researchers we have assembled and how valuable these findings are.”

Research at the NEEM site centers on climate data contained in layers of ice 1.5 miles deep, brought to the surface in 3-foot chunks through a hollow, 4-inch-wide tube during parts of three summers from 2008 to 2010. Data being analyzed reveal key information about global temperatures, sea-level rise and changes to polar ice sheets during what is known as the Eemian period, which began about 130,000 years ago and ended about 114,000 years ago. The period bridged two ice ages and is known for warm temperatures worldwide.

“From the findings within the ice core samples, we now know the Eemian period was four to eight degrees warmer than today. We already knew it was warmer, but an eight-degree spike is higher than we realized. We’ve never had data this clear or accurate,” said Dahl-Jensen.

Beyond the information contained within the small samples of ice brought to the surface for further study, Dahl-Jensen’s group relies on radars designed by KU’s CReSIS team to geographically extend these results for modeling larger areas of the ice sheet.

“The first and most important parameter to modeling an ice sheet is knowing where the bedrock is, and the radar from CReSIS detects that beautifully,” Dahl-Jensen said. “The radar detects a lot of internal layering and provides a clear picture of climate transitions over time. By analyzing these images, we can determine the conditions and the age of the ice over a large area.”

The Nature article praises KU’s CReSIS team, noting:

“The consistency of the radar images and deep ice core results at NEEM is a breakthrough result, and it demonstrates that radar imaging can now be used to predict folded ice layering. This opens the potential for a systematic reconstruction of the Eemian Greenland ice sheet layering from new radar imaging. Assimilation of such data in ice sheet models should lead to much improved histories of the configuration of the ice sheet in the past, improving our ability to predict the future evolution of the ice sheet.”

A commitment to innovation has fueled CReSIS’ success in remote sensing.

“We have substantially improved the sensitivity and capability of radars used to sound ice and image the ice bed at CReSIS over the last few years, and this is resulting in data that are very useful for a wide range of glaciological studies, including the interpretation of ice cores,” said Prasad Gogineni, Distinguished Professor of Electrical Engineering and Computer Science. Gogineni serves as director of CReSIS, which was established at KU by the National Science Foundation in 2005.

Analysis of the radar images shows a vast majority of the ice layers are undisturbed, flowing smoothly from year to year for centuries, but the radar soundings occasionally return distorted images from deep within the ice. Ice core samples taken at NEEM reveal the distortion in the radar images corresponds to ice layers mixing, which occurs when temperatures rise.

“From the ice core studies, we learned that the ice that’s broken is from the warming during the Eemian period,” Dahl-Jensen said. “We also discovered ice crystals from this period are much larger (approximately 1 inch) than those present when it’s much cooler and the ice flows smoothly. Those ice crystals are less than (a tenth of an inch).”

As layers of snow accumulate year after year on the glacial surface, they pile up and compact, transforming to solid ice about 230 feet below the surface. Sealed within the ice throughout layers that date back thousands of years are miniscule air bubbles that provide a remarkably clear snapshot of the atmospheric conditions at the time of each year’s snowfall. Using this data, researchers can accurately gauge changes to the overall ice sheet.

“About 128,000 years ago (at the outset of the Eemian), the ice was about 650 feet higher than it is today. About 122,000 years (peak temperatures during the Eemian), the ice was about 425 feet lower than today,” a drop of nearly a quarter of a mile, Dahl-Jensen said. “That tells us there was about 6,000 years of intense heat.”

Elevation changes also reveal new information about Greenland’s impact on sea level rise during the Eemian period. The Greenland ice sheet saw an overall reduction of 5 to 10 percent, which Dahl-Jensen suspects would lead to about a 6 1/2-foot rise in the sea level.

“We know from other observations that during this period, sea levels were actually 20 to 30 feet higher than today. So this tells us indirectly that Antarctica must have contributed at least 16 to 23 feet of sea level rise. Smaller glaciers in total don’t have enough volume to account for more than 2 feet of sea level rise, so Antarctica appears to have a played a bigger role,” Dahl-Jensen said.

Nature was first published in 1869 and is one of the most cited interdisciplinary scientific journals in the world.



Wanna Skype? Chancellor gets creative to surprise Truman winner. See it here: http://bit.ly/1awodaa
Rock Chalk! Junior Ashlie Koehn named KU's 18th Truman Scholar
Ashlie Koehn, a University of Kansas junior from Burns studying in Kyrgyzstan, interrupted helping her host family prepare dinner to make a Skype call on Monday evening.

.@NYTimes columnist @WCRhoden will speak at a symposium about race and sports April 23. http://t.co/UiKA9MYNv0 http://t.co/PHwCOHqcfD
Wanna Skype? Chancellor gets creative to surprise Truman winner From KU News Service: http://bit.ly/1awodaa Ashlie Koehn, a University of Kansas junior from Burns studying in Kyrgyzstan, interrupted helping her host family prepare dinner to make a Skype call on Monday evening. To her surprise, Chancellor Bernadette Gray-Little was on the other end of the call letting Koehn know she had been named a 2015 Harry S. Truman Scholar. Koehn is the 18th KU student to be named a Truman Scholar and the only 2015 recipient from the state of Kansas. Earlier this month, she was also named a 2015 Udall Scholar. And in spite of a distance of more than 10,800 kilometers and 11 time zones, Koehn’s thrill from hearing the news from the chancellor came through loud and clear. “Ashlie’s experience at KU epitomizes a quality undergraduate experience. She challenged herself in her coursework, exposed herself to different research opportunities, studied abroad in Germany, Switzerland and Kyrgyzstan, and participated in both student government and community service projects,” Gray-Little said. “This is quite a year for Ashlie. Her hard work is a wonderful reflection on her and also a great reflection on the university, and we all congratulate her.” Each new Truman Scholar receives up to $30,000 for graduate study. Scholars also receive priority admission and supplemental financial aid at some premier graduate institutions, leadership training, career and graduate school counseling, and special internship opportunities within the federal government. Koehn, a member of KU’s nationally recognized University Honors Program, is majoring in environmental studies, economics and international studies. Her goal after earning her KU degree is to pursue a master’s degree in economics at either the London School of Economics or the University of Reading, with a focus on the economics of climate change. In 2014, she received KU’s Newman Civic Engagement Award for her work establishing the Coalition against Slavery and Trafficking. Her involvement with the issue was sparked by Hannah Britton, associate professor of political science and women, gender, and sexuality studies, who hosted national conference on contemporary slavery at KU three years ago. “Ashlie and I met several times to think about what KU students could contribute to the issue of slavery and human trafficking, and the result was her founding of KU CAST,” Britton said. “After a year as president, Ashlie successfully handed the organization over to the next student leader. She demonstrated her strong leadership qualities by setting a unique goal and then pursuing it with her sense of passion, engagement and dedication. No matter the country or context, her leadership strength is evident in her coursework, her public service and her work experiences.” The University Honors Program works with a campus committee to select KU’s nominees for the Truman Scholarship and supports them during the application process. Anne Wallen, assistant director of national fellowships and scholarships, noted it was an amazing ruse to pull off the surprise. Originally, the call was set up to be between Wallen and Koehn. “I was totally not prepared to be greeted by Chancellor Gray-Little, but it was an amazing surprise for sure,” Koehn said. “As a first-generation student, it took time to learn the collegiate system, but my parents taught me to be resourceful and independent from a young age and KU and the Kansas Air National Guard have provided me with the opportunities to drive me into the future, both at graduate school and in my career. I plan to use the Truman Scholarship to pursue a career as an environmental economist helping to shape future trade agreements and leverage action on important international environmental issues, particularly concerning climate change.” Koehn also had a surprise of her own for the chancellor — the meal she was helping to prepare was not exactly typical Kansas dinner fare. On the menu with her host family in Kyrgyzstan on Monday was a traditional Kyrgyz meal called Beshbarmak, or “five fingers,” because you eat it with your hands. The dish is made of horse and sheep and was being prepared as a birthday celebration for Koehn’s host mom. Chancellor Gray-Little, as she signed off from Skype, made sure to encourage Koehn to enjoy her Beshbarmak. Koehn is the daughter of Rodney and Carolyn Koehn of Burns. She graduated from Fredric Remington High School in Moundridge. She is an active member of the Kansas Air National Guard and currently on leave while studying abroad in Bishkek, Kyrgyzstan. She is a member of the KU Global Scholars Program and a past member of the Student Senate. In addition to being named a 2015 Truman and Udall scholar, she was named a 2014 Boren Scholar and Gilman Scholar and in 2013 was named the Kansas Air National Guard Airman of the Year.


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