March 22, 2007
‘Cool’ Science: JPL Observes International Polar Year
Vast, yet remote; frigid, yet teeming with life; stark and barren, yet serenely beautiful -- these are just a few of the contradictions of Earth's polar regions.
Within their frozen confines lie secrets -- clues scientists believe can help unravel some of the mysteries that drive Earth's climate. That's because Earth's poles are sensitive barometers to climate change. They react quickly to a warmer environment, and the effects of these reactions are felt on a global scale.
In the past 125 years, scientists have coordinated three international expeditions to study the poles: in 1882, 1932 and 1957. The 1882-83 polar year led to the establishment of a series of Arctic weather stations. The 1932-33 International Polar Year expanded studies of the Arctic's meteorology and upper atmosphere, and included the second Antarctic expedition by Admiral Richard E. Byrd, conducted using both aircraft and surface observations. In 1957-58, the International Geophysical Year included major aircraft and surface research efforts in Antarctica, and saw the launch of the first artificial satellites.
The advent of the Space Age and recent technological advancements have given today's scientists new tools these earlier explorers could only have dreamed of. The time had come to put those tools to work in a new study of the polar regions. This was the genesis of the latest International Polar Year (IPY). It began on March 1 of this year and will continue through March 1, 2009, allowing researchers to conduct two annual observing cycles in each polar region.
Scientists at NASA's Jet Propulsion Laboratory, Pasadena, Calif., have joined colleagues from other NASA centers, U.S. agencies and universities, as well as more than 60 other nations, in a worldwide campaign to better understand the polar regions of Earth. NASA and JPL will also study the polar regions of the moon and Mars.
Combining the latest satellite observations from NASA and other international space agencies with airborne and ground-based instrumentation, scientists will study all aspects of the poles, including the polar land regions, ice sheets, glaciers, sea ice, oceans and atmosphere. Nearly the entire JPL armada of Earth science satellites and instruments will contribute measurements. The combination of data will give scientists new insights into the polar regions and how they're connected to the rest of the Earth system.
So why study the poles so intently? Scientists want to understand the large-scale environmental changes that are occurring in Earth's polar regions because they have major societal and economic impacts. In addition, studying them helps advance new scientific frontiers, such as understanding the role of the Antarctic and Greenland ice sheets in sea level rise.
"The International Polar Year is a unique and timely opportunity for all of us, from scientists to members of the public, regardless of our nationality or backgrounds, to bring Earth's polar regions into focus," said Eric Rignot, a JPL research scientist. "Important changes are taking place in the polar regions, with major consequences for the future. There could not have been a better time for an International Polar Year."
"The International Polar Year offers tremendous opportunities for collaboration with other scientists and for mobilizing the resources and energy needed to understand the changes that are occurring," added JPL research scientist Isabella Velicogna. "The ice sheets are changing much faster than we were expecting, and this makes our job of understanding those changes very exciting."
JPL scientists will be key contributors to International Polar Year Earth studies by:
- Generating continental-scale mosaic maps depicting how fast polar ice sheets are flowing
- Gathering information on glacier thickness in Greenland and Patagonia using a novel low-frequency airborne radar sounder
- Documenting glacier and ice shelf changes on the ground and from a series of international synthetic-aperture radar satellites
"These efforts will greatly improve our knowledge of ice sheet changes and their response to climate change," said Rignot. "They will help us improve our ability to determine how ice sheets in Greenland and Antarctica may affect global sea level in the future."
Measurements of ozone, chlorine monoxide (which destroys ozone), and related chemical species gathered by the JPL-developed and managed Microwave Limb Sounder instrument on NASA's Aura satellite are providing a 3-D view of atmospheric processes over the polar regions. These satellite measurements complement surface activities being conducted during International Polar Year. International regulations have brought about a slight decline in stratospheric chlorine, which should result in higher ozone levels.
However, changes in climate can potentially delay ozone layer recovery. The 2006 Antarctic ozone hole was the most severe on record, and the Arctic region continues to experience large ozone losses in some years. Research conducted during International Polar Year, supported by JPL satellite measurements, is focused on quantifying the relationship between climate change and ozone depletion.
NASA and JPL are also "pole-vaulting" to Mars and the moon by studying, for example, the Martian polar regions, which may hold critical clues about the habitability of the red planet.
NASA's Mars Odyssey orbiter, launched in 2001, and still active, has discovered large amounts of water ice mixed into the top one meter (three feet) of the planet's surface at high latitudes. That discovery prompted development of the Phoenix Mars Lander mission, which will launch in August and travel to a far northern Martian plain equivalent in latitude to southern Greenland. Phoenix will dig into the soil and analyze samples scooped at various depths from the surface to the icy layer. The mission includes investigation of a hypothesis that long-term climate cycles sometimes warm the icy layer enough to create conditions that could sustain microbial life.
NASA's Mars Reconnaissance Orbiter and the European Space Agency's Mars Express orbiter are using cameras, spectrometers and ground-penetrating radar to study Martian polar regions and other portions of the planet. Polar layered terrain holds a record of climate history analogous to tree rings or terrestrial ice cores (samples of accumulated snow and ice drilled from deep within ice sheets or glaciers that contain trapped air bubbles, the composition of which can provide a picture of past climate conditions).
Finally, NASA's mission to extend human exploration into the solar system begins with creating a base in the polar regions of the Earth's moon. Next year, an instrument designed, built and managed by JPL will be carried to the moon aboard the Indian Space Agency's Chandrayaan-1 spacecraft. The Moon Mineralogy Mapper is a state-of-the-art imaging spectrometer that will give scientists their first opportunity to examine lunar mineralogy at high spatial and spectral resolution. The Moon Mineralogy Mapper will map the entire lunar surface from an altitude of 100 kilometers (62 miles).
While International Polar Year will end in 2009, NASA's research into the polar regions of Earth, the moon and Mars will continue for the foreseeable future. "The work we do these next two years will lead to continued cooperation with our international IPY partners in the future," said Rignot. "IPY is only a beginning."
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