Featured Research

from universities, journals, and other organizations

New way to study permafrost soil, above and below ground

Date:
January 4, 2013
Source:
DOE/Lawrence Berkeley National Laboratory
Summary:
Scientists have developed a new way to explore the little-known world of permafrost soils, which store almost as much carbon as the rest of the world's soils and about twice as much as is in the atmosphere. The new approach combines several remote-sensing tools to study the Arctic landscape, above and below ground, in high resolution and over large spatial scales.

The scientists use data from airborne Lidar, surface geophysical measurements, and point measurements to explore the complex relationships between different layers of permafrost soil.
Credit: Image courtesy of DOE/Lawrence Berkeley National Laboratory

What does pulling a radar-equipped sled across the Arctic tundra have to do with improving our understanding of climate change? It's part of a new way to explore the little-known world of permafrost soils, which store almost as much carbon as the rest of the world's soils and about twice as much as is in the atmosphere.

The new approach combines several remote-sensing tools to study the Arctic landscape -- above and below ground -- in high resolution and over large spatial scales.It was developed by a group of researchers that includes scientists from the U.S. Department of Energy's Lawrence Berkeley National Laboratory (Berkeley Lab).

They use ground-penetrating radar, electrical resistance tomography, electromagnetic data, and LiDAR airborne measurements. Together, these tools allow the scientists to see the different layers of the terrestrial ecosystem, including the surface topography, the active layer that seasonally freezes and thaws, and the deeper permafrost layer.

The goal is to help scientists determine what will happen to permafrost-trapped carbon as the climate changes. Will it stay put? Or will it enter the atmosphere and accelerate climate change?

The scientists report their approach in a paper recently published online in the journal Hydrogeology. Their research is one of the first papers published in association with a new Department of Energy project called the Next-Generation Ecosystem Experiment (NGEE-Arctic), which seeks to gain a predictive understanding of the Arctic terrestrial ecosystem's feedback to climate. The NGEE-Arctic project is a collaboration among scientists and engineers at Oak Ridge National Laboratory, Los Alamos National Laboratory, Brookhaven National Laboratory, Berkeley Lab, and the University of Alaska Fairbanks.

"By combining surface geophysical and airborne remote-sensing methods, we have a new window that allows us to study permafrost systems like never before," says Susan Hubbard, a geophysicist in Berkeley Lab's Earth Sciences Division who leads the Lab's participation in the NGEE-Arctic collaboration.

The scientists tested their system on a plot of land near Barrow, Alaska, that measures about 500 meters long and 40 meters wide. Hubbard and her team conducted their first field campaign at the site last fall when the system was freezing up. They've since returned several times to conduct more research.

To characterize the land surface, they used data from a remote sensing device called LiDAR, which is short for Light Detection And Ranging. The device was mounted on a Cessna aircraft. It uses light to measure the microtopography, which controls water drainage in the Barrow region.

The scientists use data from airborne Lidar, surface geophysical measurements, and point measurements to explore the complex relationships between different layers of permafrost soil.

The scientists also used three tools to explore the hidden world below the surface. Ground-penetrating radar was pulled from one end of the plot to the other. They set up a string of electrodes at different locations to conduct electrical resistance tomography measurements. Electromagnetic data was collected along more than a dozen lines that spanned the length of the plot. The scientists also collected point measurements of temperature, moisture, and other properties at several locations to verify the data from the remote-sensing tools.

These geophysical measurements, coupled with the point measurements, allowed the scientists to see how the different layers of the permafrost system vary spatially, including the topography, the active layer, and the deeper permafrost. They could also see how these layers relate to each other.

These new vantages will enable the team to learn much more about how permafrost systems change over time -- and what this means for trapped carbon.

For example, permafrost is often covered by a patchwork of polygons that form over successive freeze-thaw cycles. Using their suite of tools, the scientists observed arelationship betweenthese surface polygons and the distribution of water on the surface. The LiDAR measurements revealed three types of polygon areas -- high-centered polygons, low-center polygons, and in-between -- each with unique moisture drainage characteristics (High-centered polygons shed water, while water often pools in low-centered polygons).

In addition, geophysical data and point measurement revealed a relationship between the different types of polygons and subsurface thermal, chemical, and hydrological properties. These properties control how microbes degrade soil carbon, which leads to the generation of greenhouse gasses such as carbon dioxide and methane.

More specifically, the ground-penetrating radar and electrical resistance tomography measurements provided high-resolution information about the thickness of the active layer and water content. These instruments also detected the presence of permafrost features such as ice wedges, which help form polygons.

The electromagnetic data provided information about several permafrost characteristics, including the discovery of a region that appears to be unfrozen, possibly due to the intrusion of saline water that lowers the freezing point.

"Overall, this combination of methods helps us understand the spatial and temporal interactions between surface microtopography, the active layer that controls soil respiration and generation of greenhouse gasses, and the deeper permafrost layer, which controls the formation of the polygonal features," says Hubbard. "This approach also allows us to sample over large spatial regions with minimal disturbance to the ecosystem -- two important criteria when it comes to studying the vast and delicate Arctic landscape."

NGEE-Arctic is supported by the Office of Biological and Environmental Research within the Department of Energy's Office of Science.


Story Source:

The above story is based on materials provided by DOE/Lawrence Berkeley National Laboratory. Note: Materials may be edited for content and length.


Journal Reference:

  1. S. S. Hubbard, C. Gangodagamage, B. Dafflon, H. Wainwright, J. Peterson, A. Gusmeroli, C. Ulrich, Y. Wu, C. Wilson, J. Rowland, C. Tweedie, S. D. Wullschleger. Quantifying and relating land-surface and subsurface variability in permafrost environments using LiDAR and surface geophysical datasets. Hydrogeology Journal, 2012; DOI: 10.1007/s10040-012-0939-y

Cite This Page:

DOE/Lawrence Berkeley National Laboratory. "New way to study permafrost soil, above and below ground." ScienceDaily. ScienceDaily, 4 January 2013. <www.sciencedaily.com/releases/2013/01/130104155058.htm>.
DOE/Lawrence Berkeley National Laboratory. (2013, January 4). New way to study permafrost soil, above and below ground. ScienceDaily. Retrieved April 25, 2014 from www.sciencedaily.com/releases/2013/01/130104155058.htm
DOE/Lawrence Berkeley National Laboratory. "New way to study permafrost soil, above and below ground." ScienceDaily. www.sciencedaily.com/releases/2013/01/130104155058.htm (accessed April 25, 2014).

Share This



More Earth & Climate News

Friday, April 25, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Deadly Fungus Killing Bats, Spreading in US

Deadly Fungus Killing Bats, Spreading in US

AP (Apr. 24, 2014) A disease that has killed more than six million cave-dwelling bats in the United States is on the move and wildlife biologists are worried. White Nose Syndrome, discovered in New York in 2006, has now spread to 25 states. (April 24) Video provided by AP
Powered by NewsLook.com
New Pictures of Ship That Sank in 1888

New Pictures of Ship That Sank in 1888

AP (Apr. 24, 2014) Federal researchers have released new images of the City of Chester, a steamship that sank in San Francisco Bay in 1888. Researchers recently found the shipwreck while mapping shipping routes. (April 24) Video provided by AP
Powered by NewsLook.com
Risk of Asteroid Hitting Earth Higher Than Thought, Study Shows

Risk of Asteroid Hitting Earth Higher Than Thought, Study Shows

Reuters - US Online Video (Apr. 23, 2014) A group of space explorers say the chance of a city-obliterating asteroid striking Earth is higher than scientists previously believed. Deborah Gembara reports. Video provided by Reuters
Powered by NewsLook.com
UN Joint Mission Starts Removing Landmines in Cyprus

UN Joint Mission Starts Removing Landmines in Cyprus

AFP (Apr. 23, 2014) The UN mission in Cyprus (UNFICYP) led a mine clearance demonstration on Wednesday in the UN-controlled buffer zone where demining operations are being conducted near the Cypriot village of Mammari. Duration: 01:00 Video provided by AFP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins