Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Scientists use satellite to ’pond-er’ melted Arctic ice

06.10.2003


NASA researchers and other scientists used a satellite combined with aircraft video to create a new technique for detecting ponds of water on top of Arctic sea ice. Until now, it was not possible to accurately monitor these ponds on ice from space.



Water that forms on sea ice during the summer, called a melt pond, absorbs the Sun’s energy rather than reflecting it back to space the way ice does. The balance between reflected and absorbed energy has a large effect on Arctic and global climate. When more ponds of water form on the Arctic sea ice cover in early summer, more heat is absorbed, causing the Arctic’s sea ice cover to melt faster during the summer. Knowledge of when and where these melt ponds form will help scientists calculate the balance of energy in the Arctic and improve their knowledge and projections of climate both regionally and globally.

By using detailed aircraft video of Arctic surfaces and comparing those with coarser satellite imagery, the researchers were able to recognize rough features in the satellite data that corresponded to ponds on ice, ocean water, and un-melted sea ice. Now, they are able to use a satellite to monitor sea ice, without the aid of the aircraft video. Satellites offer the advantages of frequent regular flyovers that cover vast areas all at once.


"Our new technique offers the possibility of determining when and mapping where these melt ponds form and would greatly aid our understanding of the Arctic heat balance," said co-author Donald Cavalieri, a senior research scientist at NASA’s Goddard Space Flight Center (GSFC), Greenbelt, Md. An article describing the new technique appeared in a recent issue of the journal, Remote Sensing of Environment.

During spring and summer, these melt ponds cause existing sea ice to melt faster and greatly reduce the ice’s ability to reflect sunlight. This can create a positive feedback, where an increasing number of melt ponds absorbs more heat and causes sea ice cover to melt even faster.

During the warmer months, melt ponds can cover up to 50 percent of the Arctic sea ice area. There may be a relationship between the fraction of melt ponds and the amount of sea ice cover at summer’s end. Researchers know from satellite records covering the last 30-years that the Arctic sea ice cover at summer’s end has been decreasing rapidly. This new technique may help them determine whether there has also been an increase in the number of melt ponds over this period.

This new technique to detect melt pond coverage uses NASA’s Enhanced Thematic Mapper Plus (ETM+) instrument on the Landsat 7 satellite, developed with the aid of much higher resolution video imagery from a NASA supported aircraft experiment during the summer of 2000.

"This result is an excellent example of how the coordinated use of satellites and research aircraft are used to develop new techniques for observing the Earth," Cavalieri added.

By using video footage from an aircraft flight at an altitude of almost one and a half kilometers, the researchers were able to compare that higher resolution footage with Landsat 7 images passing over the same path above Baffin Bay in the Arctic on the same day. They then compared the Landsat imagery with the aircraft video.

While Landsat 7 shows less detail, it covers vast areas all at once. The aircraft video, on the other hand, allows researchers to view a 1.5 meter area in detail.

By classifying 13 high resolution images from the aircraft into areas of ocean, ice with ponds, and pond-free ice and then comparing these areas with the different wavelength bands of Landsat, the researchers were able to develop a new method to calculate the extent of open water, melt ponds, and sea ice over large areas using Landsat data by itself.

"Previously there were no systematic measurements of melt ponds, but this technique with the Landsat creates the possibility of determining when and where these melt ponds form," Cavalieri said. "It helps us understand the heat balance, which ties into the global climate system."



Lead author Thorsten Markus, who is currently conducting research at sea, is also a scientist at NASA GSFC. Other co-authors include Mark Tschudi, National Center for Atmospheric Research, Boulder, Colo., and Alvaro Ivanoff, Science Systems and Applications, Inc., Lanham, Md.

The study was funded by NASA. NASA’s Earth Science Enterprise is dedicated to understanding the Earth as an integrated system and applying Earth System Science to improve prediction of climate, weather, and natural hazards using the unique vantage point of space.

Krishna Ramanujan | GSFC

More articles from Earth Sciences:

nachricht New Study Will Help Find the Best Locations for Thermal Power Stations in Iceland
19.01.2017 | University of Gothenburg

nachricht Water - as the underlying driver of the Earth’s carbon cycle
17.01.2017 | Max-Planck-Institut für Biogeochemie

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Traffic jam in empty space

New success for Konstanz physicists in studying the quantum vacuum

An important step towards a completely new experimental access to quantum physics has been made at University of Konstanz. The team of scientists headed by...

Im Focus: How gut bacteria can make us ill

HZI researchers decipher infection mechanisms of Yersinia and immune responses of the host

Yersiniae cause severe intestinal infections. Studies using Yersinia pseudotuberculosis as a model organism aim to elucidate the infection mechanisms of these...

Im Focus: Interfacial Superconductivity: Magnetic and superconducting order revealed simultaneously

Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.

While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...

Im Focus: Studying fundamental particles in materials

Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales

Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...

Im Focus: Designing Architecture with Solar Building Envelopes

Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.

As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Sustainable Water use in Agriculture in Eastern Europe and Central Asia

19.01.2017 | Event News

12V, 48V, high-voltage – trends in E/E automotive architecture

10.01.2017 | Event News

2nd Conference on Non-Textual Information on 10 and 11 May 2017 in Hannover

09.01.2017 | Event News

 
Latest News

New Study Will Help Find the Best Locations for Thermal Power Stations in Iceland

19.01.2017 | Earth Sciences

Not of Divided Mind

19.01.2017 | Life Sciences

Molecule flash mob

19.01.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>