study of melting ice fields

1. Rachel Haneline

2. At the Edge
By Annette Varani
1995

3. National Snow and Ice Data Center DAAC
(NSIDC DAAC)
 The NSIDC DAAC provides data and information for
snow and ice processes, particularly interactions
among snow, ice, atmosphere, and ocean, in support of
research in global change detection and model
validation. It archives and distributes cryosphere and
climate related products from several EOS sensors
including MODIS, AMSR-E, and GLAS. NSIDC also
provides general data and information services to the
cryospheric and polar processes research community

4. Background: Why They Did This…
 The extent of Arctic sea ice is seen as a insightful indicator
of climate change. Scientists agree that long-term changes
in Arctic sea ice extent could have important consequences
for Northern Hemisphere climate.
 However, sea ice extent is like the stock market -- it
fluctuates. With large differences from season to season
and year to year it can be as hard to assess a trend as
predicting the direction your investments are taking. Only
long-term tracking can give consistency to the
characteristically dramatic variations inherent to the extent
of polar sea ice.

5. Background: What They Found…
 1995 marked the accumulation of 17 years of remotely sensed passive
microwave sea ice data from polar orbiting satellites. Now, analyses of
the Arctic record show a quantifiable downtick in sea ice extent and ice
area. Researchers say the decreases seem to be accelerating, and what's
more, that the trend appears to be linked to significant shifts in
Northern Hemisphere atmospheric circulation patterns.
 Scientists at the Nansen Environmental and Remote Sensing Center
(NERSC) in Bergen, Norway, using the passive microwave record
processed by the National Snow and Ice Data Center (NSIDC) DAAC
are finding that Arctic sea ice extent -- the region with at least 15
percent ice cover -- is shrinking 2.7 percent per decade. Total ice-
covered ocean area is falling 3.4 percent per decade. These decreases
represent the overall trend from the beginning of the passive
microwave record in 1978 through mid-1995.

6. Background: The Significance
 Is the trend a harbinger of global warming, or merely the result of
interannual variability?
 The shrinking and receding sea ice has dire consequences. First, as the
white ice that normally reflects sunlight away from Earth melts, more
of the dark open water of the Arctic Ocean is exposed, absorbing heat
and causing more ice to melt. This is a loop where ice melt causes more
ice to melt.
 Second, distinctive Arctic species such as the polar bear, walrus and ice
seals depend on the sea ice; they cannot survive without it, so as the sea
ice shrinks and thins, these animals' continued existence is
jeopardized, as are the Arctic peoples whose cultures and ways of life
have depended on the animals and the ice for millennia.

7. 1995 Sea Ice Extent
January 1995 – December 1995

8. 1995 Sea Ice Extent Montage

9. 1995 Sea Ice Extent (cont.)
Within two months, the Arctic sea ice extent has receded
immensely, especially over Canada and Russia
June 1995 August 1995

10. 2004 Sea Ice Extent
January 2004 – December 2004

11. 2004 Sea Ice Extent Montage

12. 2004 Sea Ice Extent (cont.)
Again, within two months, the Sea ice extent receded a lot, especially over Russia and Canada
June 2004 August 2004

13. Larsen B Ice Shelf

14. Larsen B Ice Shelf (cont.)
Within about three months, a multitude of ice has slipped off of the Larsen B Shelf
January 21, 2002 April 13, 2002

15. Summary: What I Learned…
 Sea ice reflects up to about 80 percent of spring time solar
radiation, and from 40 to 50 percent during the summer. In winter, it
slows heat loss from the relatively warm ocean water to the cold
atmosphere. Primarily fresh water, sea ice has a strong effect on deep
water production in the Arctic peripheral seas, and influences critical
interactions within horizontal and vertical ocean structures.
 If long-term changes were to occur in the Arctic sea ice extent, it could
seriously alter the Northern Hemisphere climate.
 Scientists identify increased storm activity over the Arctic as the cause
of the decreases in ice extent in more recent years. The increase in high
latitude storm activity appears to be part of a much larger change in
Northern Hemisphere circulation and temperature patterns.
 Whether the summer time sea ice reductions in the East Siberian Sea
hold clues to global warming is still speculative, and climate
investigators are not ready to sell short on the basis of the data to date.

16. Citations:
 http://earthdata.nasa.gov/featured-stories/featured-
research/edge (At the Edge)
 http://neo.sci.gsfc.nasa.gov/Search.html (NEO 1)
 http://earthobservatory.nasa.gov/Features/WorldOfC
hange/hobet.php (NEO 2)