Multiyear Ice Studies using AMSR-E and SSM/I data

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Multiyear Ice Studies using AMSR-E and SSM/I data

• Josefino C. Comiso
• NASA Goddard Space Flight Center
• AMSR-E Annual Team Meeting
• Telluride, CO, 14-16 2008

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Scientific Motivations

• The Arctic perennial ice cover is retreating
  rapidly. The decline means that the fraction of
  thick ice type is decreasing and hence a thinning
  in the ice cover.
• Perennial ice consists of second and older ice
  types. Could AMSR-E and SSM/I data be used to
  sort out these two ice types?
• Which ice type is declining the fastest? Can we
  study separately the variability and trends of
  the third and older ice types?
• The perennial ice cover may transition into a
  dominantly second year ice cover as in the
  Antarctic before it becomes a totally seasonal
  ice type. Can we detect when this happens?

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The dramatic drop in the 2007 perennial ice cover
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Data in Winter 2008 showed Coolingand some ice
recovery
Maximum Extent in 2008
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5-year and yearly Averages of ice Area and Extent
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Accelerated Trend in the Total Arctic Sea Ice
Cover
June?
(78 96)
(1978 to 1996)
(96-08)
(1996 to 2008)
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Previous Studies on 2nd Year Ice
Tooma, S.G., et al., J. Glaciology 15(17),
225-239, 1975 Hollinger et al., J. Geophy. Res.,
1984.
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Multi-channel Signatures of Arctic sea ice

• Distinct clusters are apparent in multi-channel
  space.
• The clusters appear to be persistent from one
  year to another.

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Arctic perennial ice and2nd year ice production
The blue area in the difference map likely
represents second year ice. The signature of
this ice is shown in the scatter plot (colored in
blue) during the following winter (15 Dec
1997). The scatter plot uses 36H vs 36V vs 18V
projected to the plane of the plot.
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Signature of 2nd year Icein 1997
In a 5 by 5 pixel study area, the temporal
change in the signature of ice with positive
anomalies and also those in the seasonal and
perennial ice regions are shown for 3 different
AMSR-E frequencies. The signature of 2nd year
ice is lower but closer to that of first year
ice types than the older ice types.
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36V vs 18V vs 6V
Six Years Later 15 January 2003
6V vs 36V vs 89V
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Cluster Map
Multiyear ice Map
sub sonar Wadhams
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Multiyear ice cover using AMSR-E Data
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Multiyear Ice Cover using SSM/I data
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(No Transcript)
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SSM/I vs AMSR-E
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TheWildCard?MultiYear Ice from 1981 to 1998
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Winter and Summer MY/Perennial Ice Cover
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Summary

• The multiyear ice information during the winter
  period in the Arctic provides a means to assess
  how the older ice types has been changing.
• The signature of second year ice appears to be
  intermediate but more similar to that of first
  year ice. This explains the big difference in
  area and extent of multiyear ice in winter as
  compared to those of perennial ice.
• Multichannel cluster analysis may provide the key
  to sorting out ice types of different ages.
  This will help evaluate how and why the ice
  thickness has been changing.
• The joint use of perennial and multiyear ice
  retrievals may provide the means to identify when
  the perennial ice transitions into a dominantly
  2nd year ice cover.

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(No Transcript)
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End of Presentation
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Arctic and Antarctic Extent and Area5-year ave.
and yearly from 2005 up to mid June 2008
14 June