Featured Research

from universities, journals, and other organizations

Radar Altimetry Confirms Global Warming Is Affecting Polar Glaciers

Date:
March 21, 2006
Source:
European Space Agency
Summary:
Scientists have confirmed that climate warming is changing how much water remains locked in the Antarctic and Greenland ice sheets, according to an article published in the Journal of Glaciology.

This image of South Greenland was acquired on 16 February 2006 by Envisat's Medium Resolution Imaging Spectrometer (MERIS), working in Reduced Resolution mode.
Credit: ESA

Scientists have confirmed that climate warming is changing how much water remains locked in the Antarctic and Greenland ice sheets, according to an article published in the Journal of Glaciology.

Using radar altimeter data from ESA’s ERS-1 and ERS-2, Jay Zwally, a scientist at NASA's Goddard Space Flight Center, and his colleagues mapped the height of the ice sheets and found there was a net loss of ice from the combined sheets between 1992 and 2002 and a corresponding rise in sea level.

Polar ice plays a crucial role in regulating global climate because it reflects about 80 percent of the incoming sunlight. If the ice caps over the polar ocean melt, the ocean water would absorb a large part of the radiation energy, which would lead to further melting of the ice and further warming of the climate.

According to the NASA study, published in the March edition, 20 billion net tonnes of water are added to oceans each year as a result of Greenland’s ice sheet gaining some 11 billion tonnes of water annually, while Antarctica loses about 31 billion tonnes per year.

The study found that Antarctica lost much more ice to the sea than it gained from snowfall, resulting in an increase in sea level, while the Greenland ice sheet gained more ice from snowfall at high altitudes than it lost from melting ice along its coast.

A recent study by Eric Rignot of NASA’s Jet Propulsion Laboratory and University of Kansas scientist Pannir Kanagaratnam, published in Science in February, showed Greenland glaciers are melting into the sea twice as fast as previously believed.

Using satellite data collected between 1996 and 2005 by ESA’s remote sensing satellites ERS-1 and ERS-2, ESA’s Envisat and Canada’s Radarsat-1, they found Greenland’s southern glaciers are now dumping twice as much ice yearly into the Atlantic as they did in 1996, accounting for nearly 17 percent of the estimated 2.54 millimetre annual rise in global sea levels.

The fact that the Greenland glaciers are melting, as determined in Rignot’s study, coupled with the new findings that Greenland’s glaciers are gaining more snow at the top suggests global warming is affecting the ice sheets. When the environment becomes warmer, it builds up water in the atmosphere which can then increase snow fall over Greenland. At the same time, however, the oceans are warming causing the outer sheets of ice to melt.

The question of whether and to what extent global climate change is causing the polar ice caps to shrink is one of the topics being addressed by glaciologists, hydrologists, oceanographers and geodesists from around the world at the ‘15 Years of Progress in Radar Altimetry’ symposium in Venice, Italy, from 13-18 March 2006.

For the last 15 years, radar altimetry – an instrument originally designed to measure the sea surface height – has been successful in measuring large-scale homogenous ice surfaces of Greenland and Antarctica and providing initial global monitoring results for sea ice thickness.

However, in an effort to improve the understanding of the relationship between the Earth’s ice cover and global climate, ESA designed a mission, called CryoSat, to provide detailed views of irregular sloping edges of land ice, as well as non-homogenous ocean ice over a three-year period.

Unfortunately, the mission was lost, on 8 October 2005, due to a malfunction of the Russian rocket launcher. But on 24 February 2006, ESA received the green light from its Member States to build and launch a CryoSat recovery mission, CryoSat-2.

CryoSat-2 will be equipped with an enhanced radar altimeter instrument, called the Synthetic Aperture Interferometric Radar Altimeter (SIRAL), that will allow it to send 17 800 separate radar pulses per second down to Earth per second then record how long their echoes take to bounce back. Currently, the second generation radar altimeter on ESA's Envisat measures height using the same technique, but sends 1800 pulses down to Earth.

It is important to carry on monitoring over Greenland and Antarctica because the long-term observations by satellites provide authoritative evidence of trends and enable estimation of the consequences should such melting continue into the future.


Story Source:

The above story is based on materials provided by European Space Agency. Note: Materials may be edited for content and length.


Cite This Page:

European Space Agency. "Radar Altimetry Confirms Global Warming Is Affecting Polar Glaciers." ScienceDaily. ScienceDaily, 21 March 2006. <www.sciencedaily.com/releases/2006/03/060317112333.htm>.
European Space Agency. (2006, March 21). Radar Altimetry Confirms Global Warming Is Affecting Polar Glaciers. ScienceDaily. Retrieved July 23, 2014 from www.sciencedaily.com/releases/2006/03/060317112333.htm
European Space Agency. "Radar Altimetry Confirms Global Warming Is Affecting Polar Glaciers." ScienceDaily. www.sciencedaily.com/releases/2006/03/060317112333.htm (accessed July 23, 2014).

Share This




More Earth & Climate News

Wednesday, July 23, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

New Orleans Plans to Recycle Cigarette Butts

New Orleans Plans to Recycle Cigarette Butts

AP (July 21, 2014) New Orleans is the first U.S. city to participate in a large-scale recycling effort for cigarette butts. The city is rolling out dozens of containers for smokers to use when they discard their butts. (July 21) Video provided by AP
Powered by NewsLook.com
Shark Sightings a Big Catch for Cape Tourism

Shark Sightings a Big Catch for Cape Tourism

AP (July 21, 2014) A rise in shark sightings along the shores of Chatham, Massachusetts is driving a surge of eager vacationers to the beach town looking to catch a glimpse of a great white. (July 21) Video provided by AP
Powered by NewsLook.com
Spectacular Lightning Storm Hits London

Spectacular Lightning Storm Hits London

AFP (July 19, 2014) A spectaCular lightning storm struck the UK overnight Friday. Images of lightning strikes over the Shard and Tower Bridge in central London. Duration: 00:23 Video provided by AFP
Powered by NewsLook.com
A Centuries' Old British Tradition Is Far from a Swan Song

A Centuries' Old British Tradition Is Far from a Swan Song

AFP (July 19, 2014) As if it weren't enough that the Queen is the Sovereign of the UK and 15 other Commonwealth realms, she is also the owner of all Britain's unmarked swans. Duration: 02:18 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