Subscribe free to our newsletters via your
. Earth Science News .

Arctic lakes show climate on thin ice
by Staff Writers
Paris (ESA) Feb 05, 2014

Floating ice (light blue) and grounded ice (dark blue) in lakes of Alaska's North Slope near Barrow, as seen by ESA's ERS-2 satellite in 2011. Image courtesy Planetary Visions / University of Waterloo, Canada / ESA. Watch full animation here.

Ice in northern Alaska's lakes during winter months is on the decline. Twenty years of satellite radar imagery show how changes in our climate are affecting high-latitude environments. Changes in air temperature and winter precipitation over the last five decades have affected the timing, duration and thickness of the ice cover on lakes in the Arctic.

In this region, warmer climate conditions result in thinner ice cover on shallow lakes and, consequently, a smaller fraction of lakes freezing all the way through during winter months.

These changes in ice cover affect the local and regional climate, the dynamics of the underlying permafrost and the availability of water for residential and industrial use throughout the winter. They also alter the physical, thermal and chemical properties of the water, affecting the ecology dependent on them.

But the magnitude of these changes had not yet been comprehensively documented until now.

In a recent study of Alaska's North Slope, published in The Cryosphere, the ice regimes of shallow lakes were documented using radar images from ESA's ERS-1 and -2 satellites.

The study reveals a 22% decrease of 'grounded ice' - or ice frozen through to the lakebed - from 1991 to 2011. This is equivalent to an overall thinning of ice by 21-38 cm.

"Prior to starting our analysis, we were expecting to find a decline in ice thickness and grounded ice based on our examination of temperature and precipitation records of the past five decades from the Barrow meteorological station," said Cristina Surdu, lead author of the study.

"At the end of the analysis, when looking at trend analysis results, we were stunned to observe such a dramatic ice decline during a period of only 20 years."

The greatest change was observed during late winter (April-May) over the 20-year period, which gradually decreased from 1991 to 2005. The ice experienced a more abrupt decline during the final six years of the analysis, reaching its lowest in 2011.

Radars such as those on the ERS mission can 'see' through clouds and in the dark, providing continuous imagery over areas like northern Alaska that are prone to bad weather and long periods of darkness.

How the radar signals bounce back can also be used to determine if the lake ice was grounded or 'floating' (with water underneath).

ERS-1 operations ended in 2000 and ERS-2 retired in 2011.

While radar imagery from these two satellites, as well as from the Envisat mission - which ended in 2012 - allowed adequate monitoring of freezing lakes, continued coverage would improve the investigation of ice regimes at high latitudes.

The upcoming Sentinel-1 mission of the Copernicus programme will provide more frequent coverage of this area while ensuring global continuity of radar acquisitions for operational lake-ice monitoring.

The first of this two-satellite mission is set for launch this spring.

Read full study in The Cryosphere


Related Links
Space for our climate
Beyond the Ice Age

Comment on this article via your Facebook, Yahoo, AOL, Hotmail login.

Share this article via these popular social media networks DiggDigg RedditReddit GoogleGoogle

Memory Foam Mattress Review
Newsletters :: SpaceDaily :: SpaceWar :: TerraDaily :: Energy Daily
XML Feeds :: Space News :: Earth News :: War News :: Solar Energy News

NASA Radar Maps the Winter Pace of Iceland's Glaciers
Pasadena CA (JPL) Feb 03, 2014
A high-precision radar instrument from NASA's Jet Propulsion Laboratory, Pasadena, Calif., left Southern California for Iceland today to create detailed maps of how glaciers move in the dead of winter. This will help scientists better understand some of the most basic processes involved in melting glaciers, which are major contributors to rising sea levels. The JPL-developed instrument, wh ... read more

Fire erupts at US nuclear waste plant

Repairs may mean darker hue for Rio's iconic Christ statue

Prisoners again bolt typhoon-damaged Philippine jail

One in 4 Japan tsunami children needs psychiatric care

Oman orders NASAMS air defense system

A Proposal For The Space Debris Society

Storage system for 'big data' dramatically speeds access to information

Raytheon secures first international customer for its F-16 RACR AESA radar

Satellites Show California Water Storage at Near-Decade Low

Is there an ocean beneath our feet?

Smithsonian reports fiery-red coral species discovered in the Peruvian Pacific

Can workshops on household water use impact consumer behavior?

NASA Radar Maps the Winter Pace of Iceland's Glaciers

Arctic lakes show climate on thin ice

Greenland's fastest glacier reaches record speeds

Greenhouse "Time Machine" Sheds Light on Corn Domestication

Herbicides may not be sole cause of declining plant diversity

Local foods offer tangible economic benefits in some regions

Are invasive plants a problem in Europe? Controversial views among invasion biologists

Beneficial insects, nematodes not harmed by genetically modified, insect-resistant crops

New Indonesian volcanic eruption halts search

New quake inflicts fresh damage on Greek island

Cut off by floods, British village becomes an island

Philippine typhoon survivors brace for new storm

'Do not disappoint', Nigeria's new top brass told

Vodacom sees surge in Africa mobile data usage

Head of Algeria ruling party attacks powerful intel chief

Zambia national park mining plan draws protests

Researchers discover how brain regions work together, or alone

Experiments show human brain uses one code for space, time, distance

Neanderthal lineages excavated from modern human genomes

When populations collide

The content herein, unless otherwise known to be public domain, are Copyright 1995-2014 - Space Media Network. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA Portal Reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. Advertising does not imply endorsement,agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. Privacy Statement