Analysis comparing time-lapsed, high-resolution satellite imagery of the Ahnewetut Wetlands in Kobuk Valley National Park, Alaska, revealed an accelerated loss of surface water in shallow thaw lakes and ponds over a recent 27-year period compared to the preceding 27-year timespan. Those periods generally coincide with a well-known cooling and warming cycle known as the Pacific Decadal Oscillation, whose period is about five decades.
The analysis compared historical high-resolution aerial photography with more recent satellite imagery to quantify the evolution of 22 shallow lakes and surrounding permafrost in the park over 54 years between 1951 and 2005.
"Total water-body surface area decreased by only 0.4 percent during the first 27 years, but decreased by 5.5 percent during the second 27-year interval," said Dr. Marius Necsoiu, principal investigator for the study and a principal scientist in SwRI's Geosciences and Engineering Division. Water body surface area was relatively stable during the early, cooler time interval, with large relative losses in small ponds balanced by small relative gains in large lakes. More significant decreases in surface area occurred during the latter, warmer timespan, including complete drainage of two ponds.
Meanwhile, ice-wedge "polygons" in the soil between the water bodies (so-named because of their geometric shapes when viewed from above), transformed from having relatively low centers to relatively high centers during the more recent interval after little change was detected during the first 27 years. The change can be explained by the melting away of ice wedges that had formed the elevated rims of the polygons, leaving the rims depressed in comparison to the polygon centers.
"This project showed that semi-automated analysis of remote-sensing data can yield important information about wetland lake dynamics and permafrost degradation in remote areas where limited funding and staff shortages prevent detailed inspections on the ground," Necsoiu said.
The SwRI-funded study was published under the title, "Multi-temporal image analysis of historical aerial photographs and recent satellite imagery reveals evolution of water body surface area and polygonal terrain morphology in Kobuk Valley National Park, Alaska," by Necsoiu, Dinwiddie, Walter, Larsen, and Stothoff in the journal Environmental Research Letters.
For more information, contact Joe Fohn at (210) 522-4630, Communications Department, PO Drawer 28510, San Antonio, TX 78228-0510.
Joe Fohn | EurekAlert!
Dust from the Sahara Desert cools the Iberian Peninsula
30.04.2015 | FECYT - Spanish Foundation for Science and Technology
Two NASA views of newborn Tropical Cyclone Quang
30.04.2015 | NASA/Goddard Space Flight Center
Scientists from Nepal, Switzerland and Germany was now able to show how erosion processes caused by the monsoon are mirrored in the sediment load of a river crossing the Himalaya.
In these days, it was again tragically demonstrated that the Himalayas are one of the most active geodynamic regions of the world. Landslides belong to the...
A world-class prime systems integrator and electronic systems provider known for its rapid, innovative, and agile technology solutions, Sierra Nevada Corporation (SNC) is currently developing a new space transportation system called the Dream Chaser.
The ultimate aim is to construct a multi-mission-capable space utility vehicle, while accelerating the overall development process for this critical capability...
Today, textiles are used for more than just clothes or bags – they are high tech materials for high-tech applications. High-tech textiles must fulfill a number of functions and meet many requirements. That is why the Fraunhofer Institute for Silicate Research ISC dedicated some major developing work to this most intriguing research area. The result can now be seen at Techtextil trade show in Frankfurt from 4 to 7 May. On display will be novel textile-integrated sensors, a unique multifunctional coating system for textiles and fibers, and textile processing of glass, carbon, and ceramics fibers to fiber preforms.
Thin materials and new kinds of sensors now make it possible to integrate silicone elastomer sensors in textiles. They are suitable for applications in medical...
KAIST researchers published an article on the development of a novel technique to precisely track the 3-D positions of optically-trapped particles having complicated geometry in high speed in the April 2015 issue of Optica.
Daejeon, Republic of Korea, April 23, 2015--Optical tweezers have been used as an invaluable tool for exerting micro-scale force on microscopic particles and...
A very small and rare species of shark is swimming its way through scientific literature. But don't worry, the chances of this inches-long vertebrate biting...
23.04.2015 | Event News
23.04.2015 | Event News
13.04.2015 | Event News
30.04.2015 | Earth Sciences
30.04.2015 | Life Sciences
30.04.2015 | Press release