發信人: Morbert.bbs@ptt.cc () 看板: AtmosSci
標 題: [新聞] 格陵蘭冰原快速萎縮,每年損失冰量較新增降雪量多兩成
發信站: 批踢踢實業 (10/21/06 10:37:10 Sat)
格陵蘭冰原快速萎縮,每年損失冰量較新增降雪量多兩成
Greenland Ice Sheet on a Downward Slide
撰文：Stephen Cole（Goddard Space Flight Center, NASA）
--------------------------------------------------------------------------
For the first time NASA scientists have analyzed data from direct,
detailed satellite measurements to show that ice losses now far surpass
ice gains in the shrinking Greenland ice sheet.
http://www.nasa.gov/images/content/160994main_greenland_icesheet.jpg
Image: Greenland's massive ice sheet has lost nearly 100 gigatons of
ice annually recently, much of it in low-elevation regions along the
continent's southeastern coast, including the southern tip (pictured
here). (Credit: NASA MODIS Land Rapid Response Team)
Using a novel technique that reveals regional changes in the weight of
the massive ice sheet across the entire continent, scientists at NASA's
Goddard Space Flight Center, Greenbelt, Md., report that Greenland's
low coastal regions lost 155 gigatons (41 cubic miles) of ice per year
between 2003 and 2005 from excess melting and icebergs, while the high-
elevation interior gained 54 gigatons (14 cubic miles) annually from
excess snowfall.
"With this new analysis we observe dramatic ice mass losses concentrated
in the low-elevation coastal regions, with nearly half of the loss
coming from southeast Greenland," said lead author Scott Luthcke of
NASA Goddard's Planetary Geodynamics Laboratory. "In the 1990's the
ice was very close to balance with gains at about the same level as
losses. That situation has now changed significantly, with an annual
net loss of ice equal to nearly six years of average water flow from
the Colorado River."
The study is based on an innovative use of data from the Gravity Recovery
and Climate Experiment (GRACE) satellite that reveals detailed information
about where and when the Greenland ice mass has changed. Other recent
studies using GRACE observations have reported continent-wide ice mass
declines, but none has shown these changes in enough detail for scientists
to investigate how much different areas of the ice sheet are losing.
http://www.nasa.gov/images/content/160992main_mass_trend_greenland_md.jpg
Image: NASA satellite data has revealed regional changes in the weight
of the Greenland ice sheet between 2003 and 2005. Low coastal regions
(blue) lost three times as much ice per year from excess melting and
icebergs than the high-elevation interior (orange/red) gained from
excess snowfall.
+ High resolution:
http://www.nasa.gov/images/content/160991main_mass_trend_greenland_lg.jpg
image Credit: Scott Luthcke, NASA Goddard
To achieve this more-detailed view of the ice sheet's behavior, Luthcke
and his colleagues used a technique that brings GRACE's global view
of the Earth down to a more local and frequent view. The pair of GRACE
satellites orbiting in close formation detect changes in the Earth's
mass directly below them by measuring changes in the distance between
the two satellites as the gravitational force of the mass causes each
to speed up or slow down.
To achieve this more-detailed view of the ice sheet's behavior, Luthcke
and his colleagues used a technique that brings GRACE's global view of
the Earth down to a more local and frequent view. The pair of GRACE
satellites orbiting in close formation detect changes in the Earth's
mass directly below them by measuring changes in the distance between
the two satellites as the gravitational force of the mass causes each
to speed up or slow down.
Standard GRACE data products infer local mass changes from a global
data set of these satellite measurements. The new study used only data
from over the Greenland region.
http://www.nasa.gov/mov/161008main_GraceBeauty1web.mov
Animation:The changes in the ice sheet's mass were measured from space
by the GRACE mission. GRACE is a pair of satellites orbiting in close
formation that can detect changes in the Earth's mass directly below
them by measuring changes in the distance between the two spacecraft
as the gravitational force of the mass causes each to speed up or slow
down. Click to view animation. Credit: NASA
"With this new detailed view of the Greenland ice sheet, we have come
a long way toward resolving the differences among recent observations
and what we know about how the ice sheet behaves," said co-author Waleed
Abdalati, head of Goddard's Cryospheric Sciences Branch. "A consistent
picture from the different data sets is emerging."
"The seasonal cycle of increased mass loss during the summer melt season
and growth during winter is clearly captured," said co-author Jay Zwally,
ICESat project scientist. The new results also capture more precisely
where changes are taking place, showing that the losses of ice mass are
occurring in the same three drainage systems where other studies have
reported increased glacier flow and ice-quakes in outlet glaciers.
GRACE is a joint partnership between NASA and the German Aerospace
Center, Deutsches Zentrum fur Luft und Raumfahrt. The satellites,
launched in 2002, are managed by the Jet Propulsion Laboratory.
Continued monitoring in the future is needed to determine whether this
ice loss is a long-term trend, the authors point out. The new study
appears in Science Express, the advance edition of the journal Science,
on Oct. 19.
Related links:
+ Climate Warming on Polar Ice Sheets
http://www.nasa.gov/vision/earth/environment/ice_sheets.html
+ GRACE mission
http://www.csr.utexas.edu/grace/
+ ICESat Mission
http://icesat.gsfc.nasa.gov/
--------------------------------------------------------------------------
Greenland ice sheet shrinking fast: NASA
WASHINGTON (Reuters) - The vast sheet of ice that covers Greenland is
shrinking fast, but still not as fast as previous research indicated,
NASA scientists said on Thursday.
Greenland's low coastal regions lost 155 gigatons (41 cubic miles) of
ice each year between 2003 and 2005 from excess melting and icebergs,
the scientists said in a statement.
The high-elevation interior gained 54 gigatons (14 cubic miles) annually
from excess snowfall, they said.
This is a change from the 1990s, when ice gains approximately equaled
losses, said Scott Luthcke of NASA's Planetary Geodynamics Laboratory
outside Washington.
"That situation has now changed significantly, with an annual net loss
of ice equal to nearly six years of average water flow from the Colorado
River," Luthcke said.
Luthcke and his team reported their findings in Science Express, the
advance edition of the journal Science.
The ice mass loss in this study is less than half that reported in other
recent research, NASA said in a statement, but it still shows that
Greenland is losing 20 percent more mass than it gets in new snowfall
each year.
The Greenland ice sheet is considered an early indicator of the con-
sequences of global warming, so even a slower ice melt there raises
concerns.
"This is a very large change in a very short time," said Jay Zwally, a
co-author of the study. "In the 1990s, the ice sheet was growing inland
and shrinking significantly at the edges, which is what climate models
predicted as a result of global warming.
"Now the processes of mass loss are clearly beginning to dominate the
inland growth, and we are only in the early stages of the climate warming
predicted for this century," Zwally said.
More information is available online at
http://www.nasa.gov/vision/earth/lookingatearth/greenland_slide.html.
c Reuters 2006. All Rights Reserved
--------------------------------------------------------------------------
NASA:格陵蘭冰原快速萎縮,每年損失冰量較新增降雪量多兩成
來源：路透社
路透華盛頓電---美國太空總署(NASA)科學家周四表示，覆蓋著格陵
蘭的廣大冰原正快速萎縮，但不像先前研究所指的那麼急速。
科學家在聲明中說，在2003至2005年間，格陵蘭的低海岸區域因為陸
冰的融解和海冰的融化，每年失去1,550億噸的冰。
他們說，內陸高海拔處每年新增的降雪量為540億噸。
這是1990年代以來的一個改變，在那個年代，新增冰量和損失冰量大
致相當，NASA位於華盛頓外圍的行星地球動力學研究所的呂特克(Sco
tt Luthcke)說。
「現在情況已經有了顯著的改變，每年損失的冰量等同於科羅拉多河
將近六年的平均水量，」他說。
呂特克與其團隊的報告刊登於科學雜誌《科學快訊》(Science Expre
ss)的搶先曝光版中。
NASA在聲明中說，這項研究所發現的冰團損失量不及近期其他研究報
告的一半，但它仍顯示出格陵蘭每年損失的冰團比新增的降雪量多出
20%。
格陵蘭冰原的融解被視為全球暖化的早期跡象，所以即使冰融化得較
先前估計為慢，仍然引人擔憂。
**十數年間的大轉變**
「這是在很短的時間內很巨大的改變，」研究的共同撰述人齊瓦利(J
ay Zwally)說。「在1990年代，冰原在內陸成長，邊緣則快速萎縮，
而這正是氣候模型預測出的全球暖化結果。」
「現在冰團損失的情況顯然開始超越內陸冰原的成長，而我們還只在
預測到的本世紀氣候暖化的早期階段，」他說。
詳細資訊可參考線上網站，網址為
http://www.nasa.gov/vision/earth/lookingatearth/greenland_slide.html
(完)
--編譯 林雨蒨;審校 鄒衡天
--------------------------------------------------------------------------
來源：1.NASA
http://www.nasa.gov/vision/earth/lookingatearth/greenland_slide.html
2.REUTERS（路透社）
http://tinyurl.com/y3t4ut
3.REUTERS（yahoo.NEWS）
http://tw.news.yahoo.com/article/url/d/a/061021/16/5j5j.html
--
歈灨﹜~灨↗歈灨↗歈灨↗歈裐歈灨↗歈
矙 矙 矙 矙 矙 矙
矙 矙 矙 矙 矙 矙
矙 矙 ╯ 矙 禊 ╯裺裐歈
矙矙矙 矙 摃↗矙 矙 禊 摃↗ 矙
裺潁潁憓ｑ灨裺潁裺潁裺灨裺潁裺潁裺 裺
--
※ 發信站: 批踢踢實業坊(ptt.cc)
◆ From: 140.122.150.47
標 題: [新聞] 格陵蘭冰原快速萎縮,每年損失冰量較新增降雪量多兩成
發信站: 批踢踢實業 (10/21/06 10:37:10 Sat)
格陵蘭冰原快速萎縮,每年損失冰量較新增降雪量多兩成
Greenland Ice Sheet on a Downward Slide
撰文：Stephen Cole（Goddard Space Flight Center, NASA）
--------------------------------------------------------------------------
For the first time NASA scientists have analyzed data from direct,
detailed satellite measurements to show that ice losses now far surpass
ice gains in the shrinking Greenland ice sheet.
http://www.nasa.gov/images/content/160994main_greenland_icesheet.jpg
Image: Greenland's massive ice sheet has lost nearly 100 gigatons of
ice annually recently, much of it in low-elevation regions along the
continent's southeastern coast, including the southern tip (pictured
here). (Credit: NASA MODIS Land Rapid Response Team)
Using a novel technique that reveals regional changes in the weight of
the massive ice sheet across the entire continent, scientists at NASA's
Goddard Space Flight Center, Greenbelt, Md., report that Greenland's
low coastal regions lost 155 gigatons (41 cubic miles) of ice per year
between 2003 and 2005 from excess melting and icebergs, while the high-
elevation interior gained 54 gigatons (14 cubic miles) annually from
excess snowfall.
"With this new analysis we observe dramatic ice mass losses concentrated
in the low-elevation coastal regions, with nearly half of the loss
coming from southeast Greenland," said lead author Scott Luthcke of
NASA Goddard's Planetary Geodynamics Laboratory. "In the 1990's the
ice was very close to balance with gains at about the same level as
losses. That situation has now changed significantly, with an annual
net loss of ice equal to nearly six years of average water flow from
the Colorado River."
The study is based on an innovative use of data from the Gravity Recovery
and Climate Experiment (GRACE) satellite that reveals detailed information
about where and when the Greenland ice mass has changed. Other recent
studies using GRACE observations have reported continent-wide ice mass
declines, but none has shown these changes in enough detail for scientists
to investigate how much different areas of the ice sheet are losing.
http://www.nasa.gov/images/content/160992main_mass_trend_greenland_md.jpg
Image: NASA satellite data has revealed regional changes in the weight
of the Greenland ice sheet between 2003 and 2005. Low coastal regions
(blue) lost three times as much ice per year from excess melting and
icebergs than the high-elevation interior (orange/red) gained from
excess snowfall.
+ High resolution:
http://www.nasa.gov/images/content/160991main_mass_trend_greenland_lg.jpg
image Credit: Scott Luthcke, NASA Goddard
To achieve this more-detailed view of the ice sheet's behavior, Luthcke
and his colleagues used a technique that brings GRACE's global view
of the Earth down to a more local and frequent view. The pair of GRACE
satellites orbiting in close formation detect changes in the Earth's
mass directly below them by measuring changes in the distance between
the two satellites as the gravitational force of the mass causes each
to speed up or slow down.
To achieve this more-detailed view of the ice sheet's behavior, Luthcke
and his colleagues used a technique that brings GRACE's global view of
the Earth down to a more local and frequent view. The pair of GRACE
satellites orbiting in close formation detect changes in the Earth's
mass directly below them by measuring changes in the distance between
the two satellites as the gravitational force of the mass causes each
to speed up or slow down.
Standard GRACE data products infer local mass changes from a global
data set of these satellite measurements. The new study used only data
from over the Greenland region.
http://www.nasa.gov/mov/161008main_GraceBeauty1web.mov
Animation:The changes in the ice sheet's mass were measured from space
by the GRACE mission. GRACE is a pair of satellites orbiting in close
formation that can detect changes in the Earth's mass directly below
them by measuring changes in the distance between the two spacecraft
as the gravitational force of the mass causes each to speed up or slow
down. Click to view animation. Credit: NASA
"With this new detailed view of the Greenland ice sheet, we have come
a long way toward resolving the differences among recent observations
and what we know about how the ice sheet behaves," said co-author Waleed
Abdalati, head of Goddard's Cryospheric Sciences Branch. "A consistent
picture from the different data sets is emerging."
"The seasonal cycle of increased mass loss during the summer melt season
and growth during winter is clearly captured," said co-author Jay Zwally,
ICESat project scientist. The new results also capture more precisely
where changes are taking place, showing that the losses of ice mass are
occurring in the same three drainage systems where other studies have
reported increased glacier flow and ice-quakes in outlet glaciers.
GRACE is a joint partnership between NASA and the German Aerospace
Center, Deutsches Zentrum fur Luft und Raumfahrt. The satellites,
launched in 2002, are managed by the Jet Propulsion Laboratory.
Continued monitoring in the future is needed to determine whether this
ice loss is a long-term trend, the authors point out. The new study
appears in Science Express, the advance edition of the journal Science,
on Oct. 19.
Related links:
+ Climate Warming on Polar Ice Sheets
http://www.nasa.gov/vision/earth/environment/ice_sheets.html
+ GRACE mission
http://www.csr.utexas.edu/grace/
+ ICESat Mission
http://icesat.gsfc.nasa.gov/
--------------------------------------------------------------------------
Greenland ice sheet shrinking fast: NASA
WASHINGTON (Reuters) - The vast sheet of ice that covers Greenland is
shrinking fast, but still not as fast as previous research indicated,
NASA scientists said on Thursday.
Greenland's low coastal regions lost 155 gigatons (41 cubic miles) of
ice each year between 2003 and 2005 from excess melting and icebergs,
the scientists said in a statement.
The high-elevation interior gained 54 gigatons (14 cubic miles) annually
from excess snowfall, they said.
This is a change from the 1990s, when ice gains approximately equaled
losses, said Scott Luthcke of NASA's Planetary Geodynamics Laboratory
outside Washington.
"That situation has now changed significantly, with an annual net loss
of ice equal to nearly six years of average water flow from the Colorado
River," Luthcke said.
Luthcke and his team reported their findings in Science Express, the
advance edition of the journal Science.
The ice mass loss in this study is less than half that reported in other
recent research, NASA said in a statement, but it still shows that
Greenland is losing 20 percent more mass than it gets in new snowfall
each year.
The Greenland ice sheet is considered an early indicator of the con-
sequences of global warming, so even a slower ice melt there raises
concerns.
"This is a very large change in a very short time," said Jay Zwally, a
co-author of the study. "In the 1990s, the ice sheet was growing inland
and shrinking significantly at the edges, which is what climate models
predicted as a result of global warming.
"Now the processes of mass loss are clearly beginning to dominate the
inland growth, and we are only in the early stages of the climate warming
predicted for this century," Zwally said.
More information is available online at
http://www.nasa.gov/vision/earth/lookingatearth/greenland_slide.html.
c Reuters 2006. All Rights Reserved
--------------------------------------------------------------------------
NASA:格陵蘭冰原快速萎縮,每年損失冰量較新增降雪量多兩成
來源：路透社
路透華盛頓電---美國太空總署(NASA)科學家周四表示，覆蓋著格陵
蘭的廣大冰原正快速萎縮，但不像先前研究所指的那麼急速。
科學家在聲明中說，在2003至2005年間，格陵蘭的低海岸區域因為陸
冰的融解和海冰的融化，每年失去1,550億噸的冰。
他們說，內陸高海拔處每年新增的降雪量為540億噸。
這是1990年代以來的一個改變，在那個年代，新增冰量和損失冰量大
致相當，NASA位於華盛頓外圍的行星地球動力學研究所的呂特克(Sco
tt Luthcke)說。
「現在情況已經有了顯著的改變，每年損失的冰量等同於科羅拉多河
將近六年的平均水量，」他說。
呂特克與其團隊的報告刊登於科學雜誌《科學快訊》(Science Expre
ss)的搶先曝光版中。
NASA在聲明中說，這項研究所發現的冰團損失量不及近期其他研究報
告的一半，但它仍顯示出格陵蘭每年損失的冰團比新增的降雪量多出
20%。
格陵蘭冰原的融解被視為全球暖化的早期跡象，所以即使冰融化得較
先前估計為慢，仍然引人擔憂。
**十數年間的大轉變**
「這是在很短的時間內很巨大的改變，」研究的共同撰述人齊瓦利(J
ay Zwally)說。「在1990年代，冰原在內陸成長，邊緣則快速萎縮，
而這正是氣候模型預測出的全球暖化結果。」
「現在冰團損失的情況顯然開始超越內陸冰原的成長，而我們還只在
預測到的本世紀氣候暖化的早期階段，」他說。
詳細資訊可參考線上網站，網址為
http://www.nasa.gov/vision/earth/lookingatearth/greenland_slide.html
(完)
--編譯 林雨蒨;審校 鄒衡天
--------------------------------------------------------------------------
來源：1.NASA
http://www.nasa.gov/vision/earth/lookingatearth/greenland_slide.html
2.REUTERS（路透社）
http://tinyurl.com/y3t4ut
3.REUTERS（yahoo.NEWS）
http://tw.news.yahoo.com/article/url/d/a/061021/16/5j5j.html
--
歈灨﹜~灨↗歈灨↗歈灨↗歈裐歈灨↗歈
矙 矙 矙 矙 矙 矙
矙 矙 矙 矙 矙 矙
矙 矙 ╯ 矙 禊 ╯裺裐歈
矙矙矙 矙 摃↗矙 矙 禊 摃↗ 矙
裺潁潁憓ｑ灨裺潁裺潁裺灨裺潁裺潁裺 裺
--
※ 發信站: 批踢踢實業坊(ptt.cc)
◆ From: 140.122.150.47
全站熱搜
留言列表
