Monitoring polar climate change from space

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Monitoring polar climate change from
space Thorsten Markus Cryospheric Sciences
Branch NASA Goddard Space Flight
Center Greenbelt, MD
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IPY sea ice project in the Antarctic sea ice
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The big news last year The record minimum in
Arctic sea ice
Data from satellite passive microwave data
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Previous minimum 2005
2007
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From Rothrock et al.
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From Holland and Bitz, 2006
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February 1996
September 1996
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February 1996
September 1996
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Importance of sea ice (1) Global energy
balance Ice/snow albedo feedback
Ocean
Snow/ice
Forest
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Importance of sea ice (2) Ocean circulation
What makes the ocean move? 1) Wind-driven
surface currents 2) Thermohaline circulation
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Change in temperature 30 years after collapse of
the thermohaline circulation
Michael Vellinga, Hadley Centre
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Importance of sea ice (3) Ecology, e.g. polar
bears
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February 1996
September 1996
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?
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Processes
Precipitation
Ice drift
Moisture flux
Albedo
From Gordon and Comiso, 1988
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Antarctic sea ice increase with global warming?
Warmer temperatures More moisture More
precipitation More freshwater input into
ocean More stable Southern Ocean Less
entrainment of WDW
More sea ice production
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Antarctic sea ice increase with global warming?
Warmer temperatures More moisture More
precipitation More freshwater input into
ocean More stable Southern Ocean Less
entrainment of WDW
Thicker snow on sea ice
More thermal insulation
More snow- to-ice conversion
More sea ice production
Less basal freezing
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Change in sea ice volume as a function of
precipitation (Balance between thermal insulation
and snow-to-ice conversion)
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IPY sea ice campaign in the Antarctic sea
ice Part of the project was dedicated to validate
ICESat measurements
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What is ICESat?
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What is missing? The 3rd dimension!
ICESat (laser altimeter)
Cryosat2 (radar altimeter, 2009)
hs
?s
hf
hi
?i
?w
hs snow depth hi ice thickness hf
freeboard
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Preliminary ICESat freeboard measurements (for
cloud-free areas only) on top of AMSR-E sea ice
concentrations.
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ICESat-derived freeboard (the height over the sea
ice above water)
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It is a long process to carefully validate
satellite measurements of the polar regions and
international collaboration is essential. The
polar regions are experiencing drastic changes
and we still dont fully understand all the
processes but we cannot effort to turn our heads
away.