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 Sediment from Himalayas may have made 2004 Indian Ocean earthquake more severe
26.05.2017 | Oregon State University

nachricht Devils Hole: Ancient Traces of Climate History
24.05.2017 | Universität Innsbruck

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Can the immune system be boosted against Staphylococcus aureus by delivery of messenger RNA?

Staphylococcus aureus is a feared pathogen (MRSA, multi-resistant S. aureus) due to frequent resistances against many antibiotics, especially in hospital infections. Researchers at the Paul-Ehrlich-Institut have identified immunological processes that prevent a successful immune response directed against the pathogenic agent. The delivery of bacterial proteins with RNA adjuvant or messenger RNA (mRNA) into immune cells allows the re-direction of the immune response towards an active defense against S. aureus. This could be of significant importance for the development of an effective vaccine. PLOS Pathogens has published these research results online on 25 May 2017.

Staphylococcus aureus (S. aureus) is a bacterium that colonizes by far more than half of the skin and the mucosa of adults, usually without causing infections....

Im Focus: A quantum walk of photons

Physicists from the University of Würzburg are capable of generating identical looking single light particles at the push of a button. Two new studies now demonstrate the potential this method holds.

The quantum computer has fuelled the imagination of scientists for decades: It is based on fundamentally different phenomena than a conventional computer....

Im Focus: Turmoil in sluggish electrons’ existence

An international team of physicists has monitored the scattering behaviour of electrons in a non-conducting material in real-time. Their insights could be beneficial for radiotherapy.

We can refer to electrons in non-conducting materials as ‘sluggish’. Typically, they remain fixed in a location, deep inside an atomic composite. It is hence...

Im Focus: Wafer-thin Magnetic Materials Developed for Future Quantum Technologies

Two-dimensional magnetic structures are regarded as a promising material for new types of data storage, since the magnetic properties of individual molecular building blocks can be investigated and modified. For the first time, researchers have now produced a wafer-thin ferrimagnet, in which molecules with different magnetic centers arrange themselves on a gold surface to form a checkerboard pattern. Scientists at the Swiss Nanoscience Institute at the University of Basel and the Paul Scherrer Institute published their findings in the journal Nature Communications.

Ferrimagnets are composed of two centers which are magnetized at different strengths and point in opposing directions. Two-dimensional, quasi-flat ferrimagnets...

Im Focus: World's thinnest hologram paves path to new 3-D world

Nano-hologram paves way for integration of 3-D holography into everyday electronics

An Australian-Chinese research team has created the world's thinnest hologram, paving the way towards the integration of 3D holography into everyday...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Marine Conservation: IASS Contributes to UN Ocean Conference in New York on 5-9 June

24.05.2017 | Event News

AWK Aachen Machine Tool Colloquium 2017: Internet of Production for Agile Enterprises

23.05.2017 | Event News

Dortmund MST Conference presents Individualized Healthcare Solutions with micro and nanotechnology

22.05.2017 | Event News

 
Latest News

How herpesviruses win the footrace against the immune system

26.05.2017 | Life Sciences

Water forms 'spine of hydration' around DNA, group finds

26.05.2017 | Life Sciences

First Juno science results supported by University of Leicester's Jupiter 'forecast'

26.05.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>