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Volume 15, Number 7
April 12, 2009

nature

Also in this section:
Looking the other way on global warming
A martial arts solution to hospitals being taken out by disasters?
End of dry season colors
Trying to catch up with drug-resistant TB


Looking the other way on global warming
by Eric Jackson, graphics and captions by NASA

Yes, there are powerful people and institutions still in denial, but the global warming issue has informed Panamanian eyes looking north. There, in the Arctic Ocean, the ice cap is melting faster than the experts had expected just a few years ago and it's going to mean brief but expanding northern shipping seasons in which vessels can bypass the Panama Canal and take thousands of miles off of the distances between ports in northeastern Asia and the upper Atlantic seaboard of North America, and between northeastern Asia and northwestern Europe.

But of course, that's not the only effect that polar melting will have on Panama. It's also going to make global sea levels rise and as a small country with two long coastlines we are going to have to make many adjustments. Some of these will be large and others small, some are easily predictable and others are likely to hit us from out of the blue.

And it's not just the Arctic. There is also a melting process underway in the Antarctic, which will also contribute to rising sea levels along Panama's coasts. The changes that are ongoing in the Antarctic are being monitored by the earth observation satellites of the space agencies of several industrialized nations, most of all the US National Aeronautics and Space Administration (NASA).


Byrd Glacier
Size: 40 by 80 kilometers (24.8 by 49.6 miles)
Location: 80.3 degrees South latitude, 159 degrees East longitude
Orientation: East at top
Image Data: ASTER Bands 3, 2, and 1
Original Data Resolution: 15 meters (49.2 feet)
Date Acquired: December 12, 2007
Image Credit: NASA/GSFC/METI/ERSDAC/JAROS,
and US/Japan ASTER Science Team

Byrd Glacier is a major glacier in Antarctica. About 135 kilometers (84 miles) long and 24 kilometers (15 miles) wide, it drains an extensive area of the polar plateau and flows eastward between the Britannia Range and the Churchill Mountains to discharge into the Ross Ice Shelf. This image was created with data from the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) instrument on NASA's Terra satellite.

Using data from ASTER, along with data from other NASA satellites, the Japanese Advanced Land Observing Satellite and the French SPOT satellite, researchers at the universities of Maine and Washington recently discovered a year-long increase in the flow speed of the glacier due to sub-glacial floods and drainage of two large sub-glacial lakes. Scientists want to know more about the processes that control the speed of such glaciers. Should they happen at larger scales, they could cause sea level to rise more rapidly.

With its 14 spectral bands from the visible to the thermal infrared wavelength region and its high spatial resolution of 15 to 90 meters (about 50 to 300 feet), ASTER images Earth to map and monitor the changing surface of our planet.

ASTER is one of five Earth-observing instruments launched December 18, 1999, on NASA's Terra satellite. The instrument was built by Japan's Ministry of Economy, Trade and Industry. A joint US/Japan science team is responsible for validation and calibration of the instrument and the data products.

The broad spectral coverage and high spectral resolution of ASTER provides scientists in numerous disciplines with critical information for surface mapping and monitoring of dynamic conditions and temporal change. Example applications are: monitoring glacial advances and retreats; monitoring potentially active volcanoes; identifying crop stress; determining cloud morphology and physical properties; wetlands evaluation; thermal pollution monitoring; coral reef degradation; surface temperature mapping of soils and geology; and measuring surface heat balance.

The US science team is located at NASA's Jet Propulsion Laboratory, Pasadena, Calif. The Terra mission is part of NASA's Science Mission Directorate.

More information about ASTER is available at http://asterweb.jpl.nasa.gov/.


Larsen B ice shelf
Image Credit: NASA/GSFC/LaRC/JPL, MISR Team

Both single and multi-angle views of the breakup of the northern section of the Larsen B ice shelf are shown in this image pair from the Multi-angle Imaging SpectroRadiometer. The Larsen B ice shelf collapsed and broke away from the Antarctic Peninsula during February and March, 2002 -- a progression observed by Terra's Moderate-resolution Imaging SpectroRadiometer (MODIS) and analyzed at the University of Colorado's National Snow and Ice Data Center. The collapse is thought to have been accelerated by warm summer temperatures which caused meltwater to fill crevasses along the landward side of the Larsen shelf, leading to intensified pressures within the sheet structure.

In the view above, spectral variations across the scene are highlighted by using near-infrared, red and blue data from MISR's nadir (vertical-viewing) camera. Here, the ice within the disintegrating ice shelf appears vibrant blue. Water has an intrinsic blue color due to the selective absorption of longer wavelengths such as red and infrared, and the translucent properties of ice within the collapsing shelf enables this absorption to be observed. The use of the near-infrared band within this false-color composite accentuates the effect. Light brownish streaks across the splintering sheet can also be discerned, and probably indicate regions where rocks and morainal debris were exposed from the interior of the shelf.

Below, data from three different view angles and only one color channel were combined to create a multi-angle composite. This image displays red-band data from MISR's 46-degree forward, nadir, and 46-degree backward-viewing cameras as red, green and blue, respectively. Here, the disintegrating ice shelf and the rough crevasses of glaciers appear orange. In contrast to the spectral composite, which provides information on the chemical composition of water ice, the colors in the image below represent properties related to its physical nature. Because vertical protrusions or depressions within textured surfaces appear brighter on their illuminated faces, the orange color in the multi-angle composite suggests a macroscopically rough ice surface. Low clouds in the multi-angle view appear purple due to their ability to both forward scatter and backward scatter sunlight. Higher clouds and mountainous terrain are subject to geometric parallax which splits the imagery into spatially separated components, and their unusual appearance is an artifact of this effect.

These views were acquired on March 7, 2002, during Terra orbit 11798. Each image represents an area of approximately 149 kilometers x 186 kilometers.

MISR was built and is managed by NASA's Jet Propulsion Laboratory, Pasadena, CA, for NASA's Office of Earth Science, Washington, DC. The Terra satellite is managed by NASA's Goddard Space Flight Center, Greenbelt, MD. JPL is a division of the California Institute of Technology.

Also in this section:
Looking the other way on global warming
A martial arts solution to hospitals being taken out by disasters?
End of dry season colors
Trying to catch up with drug-resistant TB


Panama Hotel: Luxury apartment rentals in Casco Viejo, Panama City
Panama Real Estate: Original travel and investment articles on The Panama Report
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