The Ends of the Earth: Studying the Polar Regions

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The Ends of the Earth Studying the Polar Regions

• Guest Scientist Michael Studinger
• Originally Presented 11 Feb 2006

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IPY 2007 - 2008

• IGYInternational Geophysical Year1957 1958
• Sputnik, Van Allen Belts, exploration of
  Antarctica
• Large-scale international cooperative
  investigations
• International Polar Year 2007 - 2008

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http//www.ipy.org/

• What is IPY?
• IPY Timeline
• IPY Draft Themes

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Satellite Studies of Polar Regions

• Making accurate observations in polar regions is
  difficult and, for people, dangerous
• So one of the most important advances during the
  last 50 years is use of satellite observation
• Several polar-orbiting satellites with a variety
  of instruments routinely observe winds, ice, and
  other conditions

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NASAs Earth Observing System

• TERRA
• ASTER Advanced Spaceborne Thermal Emission and
  Reflection Radiometer
• CERES Clouds and the Earth's Radiant Energy
  System
• MODIS Moderate-resolution Imaging
  Spectroradiometer

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A Tour of the Cryosphere

• NASA recently released an 8-minute multimedia
  DVD, which is also available on the Internet at
  http//www.nasa.gov/vision/earth/environment/cryos
  phere.html

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Even so, for those of us in the US and most of
the Northern Hemisphere, the Southern Hemisphere
is largely Terra Incognito

• We can look at maps, such as the one in the
  next slide, and see shapes and names.
• But we tend to think of the Southern Ocean
  and surrounding land masses merely as the bottom
  half of maps or globes. New techniques are
  beginning to allow us to show more about this
  interesting portion of our planet
• http//www.ngdc.noaa.gov/mgg/image/predict.gif

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http//tea.armadaproject.org/activity/demello/ICE_
CONTINENT_ENCOUNTER.docAntarcticMaps
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Our focus today will be on studying features
beneath the ice sheets of Antarctica

• In the Nov 2003 E2C Workshop, Dr. Studinger
  paired with Dr. Martin Visbeck to describe their
  researches about Antarctica and ocean currents
  http//www.earth2class.org/k12/w3_f2003/index
  .htm
• In April 2005, Dr. Studinger explained more about
  how scientists understand features hidden
  beneath polar ice capshttp//www.earth2class.org/
  k12/w8_s2005/index.php
• Today, he will discuss his more recent
  investigations and discoveries

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Useful background informationThe most important
feature about Antarctica is that it is now very
cold!

• Located at Earths southern pole means
  that little or no solar energy is received during
  half the year, and although the sun shines for
  long day lengths in the other half, not much
  energy is absorbed

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But it wasnt always this way!

• 200 mya, what was to become Antarctica was at the
  center of Gondwanaland, the southern
  supercontinent created as Pangaea began to split
  apart
• It was connected to Australia, Africa, South
  America, India, and New Zealand
• Fossils provide evidence that climate was much
  warmer and lush vegetation covered much of the
  surface
• Any polar ice cap was much smaller, so sea level
  was much higher

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Becoming Antarctica

• Formation of the Circumpolar Current (West Wind
  Drift) played a major role in isolating and
  cooling Antarctica
• Changes in ocean circulation had major effects on
  energy transfer on the globe, which will explored
  in the next few slides
• Consequently, the ice cap grew and sea level was
  lowered, and Antarctica became Earths ice box

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• You can study an animation from a PBS NOVA
  program showing the breakup of Gondwanaland at
• http//www.pbs.org/wgbh/nova/eden/media/stt.html

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Modern Antarctica results largely from its
isolation at the pole and the ocean currents that
surround it.
http//www.windows.ucar.edu/tour/link/earth/Water
/images/Surface_currents_jpg_image.html
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What did you notice abut these currents?

• The Southern Ocean is the only area of the world
  with flow uninterrupted by land
• The general movement is west-to-east
• There are connections with other surface currents
  to the north and poleward
• These involve both wind-driven surface currents
  and density-driven deeper circulations

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Connections between Surface and Deep-Sea Currents

• In the past few years, greater
  under-standings have developed concerning the
  elaborate interactions between the wind-driven
  surface patterns and the thermo-haline
  (temperature and salinity) deeper flows.
• One model of this is the Ocean Conveyor
  Belt, depicted in the next slide

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http//www.grida.no/climate/vital/32.htm
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Much attention has been given to this model,
especially speculations about what might happen
if it changes

• LDEOs Wally Broecker, who helped devise
  this model, recently considered the impact on
  climate that might ensue if the conveyor belt
  slowed or stopped
• http//faculty.washington.edu/wcalvin/teaching/Bro
  ecker99.html

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Returning to our Southern Hemisphere focus,
lets consider a model of what happens as the
ocean currents flow around the world. Of special
consideration are places where land masses
constrict their movements, such as Drakes
Passage between South American and Antarctica
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Warm circumpolar water passes through the Drake
Passage and flows eastward in the Antarctic
Circumpolar Current (red arrow). Some of the flow
is diverted southward into the Weddell Gyre and
becomes more dense, sinks, and flows out near the
bottom (blue arrow). The inset illustrates the
two processes that increase the density lowering
the temperature by giving up heat to the
atmosphere, and raising the salinity of the
remaining sea water by forming nearly salt-free
ice in the very cold environment.

• http//www.nsf.gov/pubs/1996/nstc96rp/sb6.htm

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So the circulation patterns around Antarctica
play major roles in global air-sea exchanges
http//www.glacier.rice.edu/oceans/4_antsurfwater.
html
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What lies beneath Antarcticas Ice?

http//www.earthinstitute.columbia.edu/news/story3
_2_01.html
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And what does Lake Vostok look like?

• From the surface, nothing that would
  indicate theres an interesting lake can be seen
• In fact, more than 70 subglacial lakes have
  been identified by remote sensing

http//www.earthinstitute.columbia.edu/news/story3
_2_01a.html
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Probing Beneath the Ice Cap

• Between 1988 1997, NASAs RADARSAT program
  studied our planet using SAR (Synthetic Aperture
  Radar) techniques.
• (Jeff Weissel presented an E2C Workshop in May
  2004 about SAR strategies to provide rapid
  response to natural hazards)
• NASAs Scientific Visualization Studio has
  created an animation using these data.

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Lake Vostok Animation

• LDEO scientists Robin Bell, Michael Studinger,
  and colleagues have created their animation about
  Lake Vostok
• http//www.earthinstitute.columbia.edu/news/vostok
  /vostok.swf

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• In his talk, Dr. Studinger will describe these
  techniques and what has been learned in more
  detail.
• You can view his web pages about Lake Vostok
  through
• http//www.ldeo.columbia.edu/mstuding/vostok

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Life Under Extreme Conditions

• One of the major reasons to study Lake Vostok is
  that it is possible that bacteria and other
  microbes may exist under the ice in vast extreme
  ecosystems.
• Understanding how these extremophiles exist may
  be vital to studying possible lifeforms
  elsewhere, especially Europa, the frozen moon of
  Jupiter

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Antarctic seas also teem with interesting
lifeforms and ecosystems

• Dr. Sam Bowser was the 2003 Keynote Speaker at
  the 108th STANYS Conference
• Dr. Bowsers research about foraminifer and other
  life in Antarctic waters is available at

http//members.global2000.net/bowser/
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• For all these reasons and more,
  understanding Antarctica, Lake Vostok, and other
  polar regions pose some of the most interesting
  and potentially important research questions
  facing us at the start of the 21st century.