Andrew Yee[_1_]
September 16th 08, 03:24 AM
ESA News
http://www.esa.int
28 August 2008
Arctic ice on the verge of another all-time low
Following last summer's record minimum ice cover in the Arctic, current
observations from ESA's Envisat satellite suggest that the extent of polar
sea-ice may again shrink to a level very close to that of last year.
Envisat observations from mid-August depict that a new record of low sea-ice
coverage could be reached in a matter of weeks. The animation above is a
series of mosaics of the Arctic Ocean created from images acquired between
early June and mid-August 2008 from the Advanced Synthetic Aperture Radar
(ASAR) instrument aboard Envisat. The dark grey colour represents ice-free
areas while blue represents areas covered with sea ice.
Current ice coverage in the Arctic has already reached the second absolute
minimum since observations from space began 30 years ago. Because the extent
of ice cover is usually at its lowest about mid-September, this year's
minimum could still fall to set another record low.
Each year, the Arctic Ocean experiences the formation and then melting of
vast amounts of ice that floats on the sea surface. An area of ice the size
of Europe melts away every summer reaching a minimum in September. Since
satellites began surveying the Arctic in 1978, there has been a regular
decrease in the area covered by ice in summer -- with ice cover shrinking to
its lowest level on record and opening up the most direct route through the
Northwest Passage in September 2007.
The direct route through the Northwest Passage -- highlighted in the image
above by an orange line -- is currently almost free of ice, while the
indirect route, called the Amundsen Northwest Passage, has been passable for
almost a month. This is the second year in a row that the most direct route
through the Northwest Passage has opened up.
Prof. Heinrich Miller from the Alfred Wegener Institute (AWI) in
Bremerhaven, Germany commented that, "Our ice-breaking research vessel
'Polarstern' is currently on a scientific mission in the Arctic Ocean.
Departing from Iceland, the route has taken the ship through the Northwest
Passage into the Canadian Basin where geophysical and geological studies
will be carried out along profiles into the Makarov Basin to study the
tectonic history and submarine geology of the central Arctic Ocean. In
addition, oceanographic as well as biological studies will be carried out.
Polarstern will circumnavigate the whole Arctic Ocean and exit through the
Northeast Passage."
Regarding the use of satellite data for polar research Miller continues,
"The polar regions, especially the Arctic, are very sensitive indicators of
climate change. The UNs Intergovernmental Panel on Climate Change has shown
that these regions are highly vulnerable to rising temperatures and
predicted that the Arctic would be virtually ice-free in the summer months
by 2070. Other scientists claim it could become ice-free as early as 2040.
Latest satellite observations suggest that the Arctic could be mainly
ice-free even earlier."
Miller added, "At AWI we place particular emphasis on studying Arctic
sea-ice, and along with in-situ studies of sea-ice thickness change
satellite data have been used extensively -- not only for the regular
observation of changes in the Arctic and Antarctic, but also for optimising
the operation of Polarstern in regions covered by sea ice."
The Arctic is one of the most inaccessible regions on Earth, so obtaining
measurements of sea ice was difficult before the advent of satellites. For
more than 20 years, ESA has been providing satellite data for the study of
the cryosphere and hence revolutionising our understanding of the polar
regions.
Satellite measurements from radar instruments can acquire images through
clouds and also at night. This capability is especially important in areas
prone to long periods of bad weather and extended darkness -- conditions
frequently encountered in the polar regions.
By making available a comprehensive dataset from its Earth Observation
satellites and other ground and air-based capabilities, ESA is currently
also contributing to one of the most ambitious coordinated science programme
ever undertaken in the Arctic and Antarctic -- the International Polar Year
2007-2008.
Further exploitation of data collected over the Arctic since 1991 is part of
an ESA Initiative on Climate Change that will be proposed to the ESA Member
States at its Ministerial Conference in November 2008. The proposal aims to
ensure delivery of appropriate information on climate variables derived from
satellites.
In 2009, ESA will make another significant contribution research into the
cryosphere with the launch of CryoSat-2. The observations made over the
three-year lifetime of the mission will provide conclusive evidence on the
rates at which ice thickness and cover is diminishing.
[NOTE: Images and weblinks supporting this release are available at
http://www.esa.int/esaCP/SEMCKX0SAKF_index_1.html ]
http://www.esa.int
28 August 2008
Arctic ice on the verge of another all-time low
Following last summer's record minimum ice cover in the Arctic, current
observations from ESA's Envisat satellite suggest that the extent of polar
sea-ice may again shrink to a level very close to that of last year.
Envisat observations from mid-August depict that a new record of low sea-ice
coverage could be reached in a matter of weeks. The animation above is a
series of mosaics of the Arctic Ocean created from images acquired between
early June and mid-August 2008 from the Advanced Synthetic Aperture Radar
(ASAR) instrument aboard Envisat. The dark grey colour represents ice-free
areas while blue represents areas covered with sea ice.
Current ice coverage in the Arctic has already reached the second absolute
minimum since observations from space began 30 years ago. Because the extent
of ice cover is usually at its lowest about mid-September, this year's
minimum could still fall to set another record low.
Each year, the Arctic Ocean experiences the formation and then melting of
vast amounts of ice that floats on the sea surface. An area of ice the size
of Europe melts away every summer reaching a minimum in September. Since
satellites began surveying the Arctic in 1978, there has been a regular
decrease in the area covered by ice in summer -- with ice cover shrinking to
its lowest level on record and opening up the most direct route through the
Northwest Passage in September 2007.
The direct route through the Northwest Passage -- highlighted in the image
above by an orange line -- is currently almost free of ice, while the
indirect route, called the Amundsen Northwest Passage, has been passable for
almost a month. This is the second year in a row that the most direct route
through the Northwest Passage has opened up.
Prof. Heinrich Miller from the Alfred Wegener Institute (AWI) in
Bremerhaven, Germany commented that, "Our ice-breaking research vessel
'Polarstern' is currently on a scientific mission in the Arctic Ocean.
Departing from Iceland, the route has taken the ship through the Northwest
Passage into the Canadian Basin where geophysical and geological studies
will be carried out along profiles into the Makarov Basin to study the
tectonic history and submarine geology of the central Arctic Ocean. In
addition, oceanographic as well as biological studies will be carried out.
Polarstern will circumnavigate the whole Arctic Ocean and exit through the
Northeast Passage."
Regarding the use of satellite data for polar research Miller continues,
"The polar regions, especially the Arctic, are very sensitive indicators of
climate change. The UNs Intergovernmental Panel on Climate Change has shown
that these regions are highly vulnerable to rising temperatures and
predicted that the Arctic would be virtually ice-free in the summer months
by 2070. Other scientists claim it could become ice-free as early as 2040.
Latest satellite observations suggest that the Arctic could be mainly
ice-free even earlier."
Miller added, "At AWI we place particular emphasis on studying Arctic
sea-ice, and along with in-situ studies of sea-ice thickness change
satellite data have been used extensively -- not only for the regular
observation of changes in the Arctic and Antarctic, but also for optimising
the operation of Polarstern in regions covered by sea ice."
The Arctic is one of the most inaccessible regions on Earth, so obtaining
measurements of sea ice was difficult before the advent of satellites. For
more than 20 years, ESA has been providing satellite data for the study of
the cryosphere and hence revolutionising our understanding of the polar
regions.
Satellite measurements from radar instruments can acquire images through
clouds and also at night. This capability is especially important in areas
prone to long periods of bad weather and extended darkness -- conditions
frequently encountered in the polar regions.
By making available a comprehensive dataset from its Earth Observation
satellites and other ground and air-based capabilities, ESA is currently
also contributing to one of the most ambitious coordinated science programme
ever undertaken in the Arctic and Antarctic -- the International Polar Year
2007-2008.
Further exploitation of data collected over the Arctic since 1991 is part of
an ESA Initiative on Climate Change that will be proposed to the ESA Member
States at its Ministerial Conference in November 2008. The proposal aims to
ensure delivery of appropriate information on climate variables derived from
satellites.
In 2009, ESA will make another significant contribution research into the
cryosphere with the launch of CryoSat-2. The observations made over the
three-year lifetime of the mission will provide conclusive evidence on the
rates at which ice thickness and cover is diminishing.
[NOTE: Images and weblinks supporting this release are available at
http://www.esa.int/esaCP/SEMCKX0SAKF_index_1.html ]