Featured Research

from universities, journals, and other organizations

Snowmelt In Antarctica Creeping Inland, Based On 20 Year Of NASA Data

Date:
September 24, 2007
Source:
NASA/Goddard Space Flight Center
Summary:
In a new NASA study, researchers using 20 years of data from space-based sensors have confirmed that Antarctic snow is melting farther inland from the coast over time, melting at higher altitudes than ever and increasingly melting on Antarctica's largest ice shelf.

A map of Antarctica indicates first time persistent melting detected within the study period from 1987-2006. Areas where persistent melting took place are shown in darker shades of green.
Credit: NASA/Rob Simmon

On the world's coldest continent of Antarctica, the landscape is so vast and varied that only satellites can fully capture the extent of changes in the snow melting across its valleys, mountains, glaciers and ice shelves.

In a new NASA study, researchers using 20 years of data from space-based sensors have confirmed that Antarctic snow is melting farther inland from the coast over time, melting at higher altitudes than ever and increasingly melting on Antarctica's largest ice shelf.

With a surface size about 1.5 times the size of the United States, Antarctica contains 90 percent of Earth's fresh water, making it the largest potential source of sea level rise. It is also a place where snow melting is quite limited because even in summer, most areas typically record temperatures well below zero.

Nevertheless, NASA researchers using data collected from 1987 to 2006 found snow melting in unlikely places in 2005: as far inland as 500 miles away from the Antarctic coast and as high as 1.2 miles above sea level in the Transantarctic Mountains.

The 20-year data record was three times longer than previous studies and reaffirmed the extreme melting irregularity observed in 2005. During the same period, they also found that melting had increased on the Ross Ice Shelf, both in terms of the geographic area affected and the duration of increased melting across affected areas.

"Snow melting is very connected to surface temperature change, so it's likely warmer temperatures are at the root of what we've observed in Antarctica," said lead author Marco Tedesco, a research scientist at the Joint Center for Earth Systems Technology cooperatively managed by NASA's Goddard Space Flight Center, Greenbelt, Md., and the University of Maryland at Baltimore County, Baltimore. The study will be published on Sept. 22 in the American Geophysical Union's Geophysical Research Letters.

The Special Sensor Microwave Imager radiometer aboard the Defense Meteorological Satellite Program's satellites provided the researchers an update on previous studies by showing evidence of persistent snow melting -- melting that occurs for at least three days or for one consecutive day and night. As the sensors fly over Antarctica, they measure the radiation naturally emitted by snow and ice at microwave frequencies. Unlike visible sensors, Microwave instruments can also detect melting below the snow surface.

"Microwave instruments are very sensitive to wet snow and can see through clouds day and night, allowing us to separate melting from dry snow to better understand when, where and for how long melting took place," said Tedesco.

Although the researchers observed less melting in some locations on the continent during the 20-year period, melting increased in others such as the Ross Ice Shelf. Increased snowmelt on the ice shelf surface can lead to melt ponds, with meltwater filling small cracks. The liquid water puts pressure on the cracks causing larger fractures in the ice shelf.

"Persistent melting on the Ross Ice Shelf is something we should not lose sight of because of the ice shelf's role as a 'brake system' for glaciers," said Tedesco. "Ice shelves are thick ice masses covering coastal land with extended areas that float on the sea, keeping warmer marine air at a distance from glaciers and preventing a greater acceleration of melting. The Ross Ice Shelf acts like a freezer door, separating ice on the inside from warmer air on the outside. So the smaller that door becomes, the less effective it will be at protecting the ice inside from melting and escaping."

The study's results from the satellite data support related research reporting a direct link between changes in near surface air temperatures and the duration and geographic area of snow melting on Antarctica. These studies, when taken together, indicate a relationship to climate change.

"Satellites have given us a remarkable ability to monitor the melting trends of glaciers and ice shelves on this immense and largely unknown continent, and to watch for unusual occurrences like those observed in 2005," said co-author Waleed Abdalati, head of the Cryospheric Sciences Branch at NASA's Goddard Space Flight Center. "Through this space-based perspective, we are really only just beginning to understand the nature of the changes that are occurring in Antarctica, and what these changes will mean for Antarctica's future contributions to sea level."


Story Source:

The above story is based on materials provided by NASA/Goddard Space Flight Center. Note: Materials may be edited for content and length.


Cite This Page:

NASA/Goddard Space Flight Center. "Snowmelt In Antarctica Creeping Inland, Based On 20 Year Of NASA Data." ScienceDaily. ScienceDaily, 24 September 2007. <www.sciencedaily.com/releases/2007/09/070920122154.htm>.
NASA/Goddard Space Flight Center. (2007, September 24). Snowmelt In Antarctica Creeping Inland, Based On 20 Year Of NASA Data. ScienceDaily. Retrieved October 1, 2014 from www.sciencedaily.com/releases/2007/09/070920122154.htm
NASA/Goddard Space Flight Center. "Snowmelt In Antarctica Creeping Inland, Based On 20 Year Of NASA Data." ScienceDaily. www.sciencedaily.com/releases/2007/09/070920122154.htm (accessed October 1, 2014).

Share This



More Earth & Climate News

Wednesday, October 1, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Raw: 12 More Bodies Found on Japan Volcano

Raw: 12 More Bodies Found on Japan Volcano

AP (Oct. 1, 2014) — A dozen more bodies were found Wednesday as Japanese rescuers resumed efforts to find survivors and retrieve bodies of those trapped by Mount Ontake's eruption. (Oct. 1) Video provided by AP
Powered by NewsLook.com
Cultural Learning In Wild Chimps Observed For The First Time

Cultural Learning In Wild Chimps Observed For The First Time

Newsy (Oct. 1, 2014) — Cultural transmission — the passing of knowledge from one animal to another — has been caught on camera with chimps teaching other chimps. Video provided by Newsy
Powered by NewsLook.com
Raw: Trapped Scientist Rescued from Cave in Peru

Raw: Trapped Scientist Rescued from Cave in Peru

AP (Oct. 1, 2014) — A Spanish scientist, who spent 12 days trapped about 1300 feet underground in a cave in Peru's remote Amazon region, was rescued on Tuesday. (Oct. 1) Video provided by AP
Powered by NewsLook.com
Earth Has Lost Half Its Vertebrate Wildlife Since 1970: WWF

Earth Has Lost Half Its Vertebrate Wildlife Since 1970: WWF

Newsy (Sep. 30, 2014) — A new study published by the World Wide Fund for Nature found that more than half of the world's wildlife population has declined since 1970. Video provided by Newsy
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:

Strange & Offbeat Stories

 

Plants & Animals

Earth & Climate

Fossils & Ruins

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