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Volume 46 | Issue 2 | March 2004

Research Roundup

photo: research

This stream, photographed during NASA's AirSAR 2004 campaign, is located in the La Selva region of the Costa Rican rain forest. The goal of the mission is to unearth archeological secrets and preserve resources and biological and cultural diversity. Dryden photographer Jim Ross and videographer Lori Losey are documenting the beauty and uniqueness encountered during the AirSAR mission. The AirSAR (Airborne Synthetic Aperture Radar) is an all-weather imaging tool developed and managed by NASA's Jet Propulsion Laboratory, Pasadena, Calif. Carried aboard a NASA DC-8 Airborne Science laboratory, it can penetrate clouds and also collect data at night.
NASA Photo / Jim Ross

Earth Science: From dense rain forests to frigid Antarctica

By Beth Hagenauer and Alan Buis
Dryden Public Affairs and JPL Public Affairs

An international team of scientists from NASA and other research institutions has embarked on a three-week expedition of discovery that will take them from the dense rain forests of Central America to the frigid isolation of Antarctica.

Armed with a unique radar instrument, the team will survey selected sites in Central America in efforts to unearth archaeological secrets and preserve resources and biological and cultural diversity. Scientists will then move to South America's Patagonian ice fields and Antarctica to conduct topographic surveys aimed at gauging the effects of climate change in that region.

The team's savvy tour guide is AirSAR, an all-weather imaging tool. Developed and managed by NASA's Jet Propulsion Laboratory, Pasadena, Calif., AirSAR is the Airborne Synthetic Aperture Radar. Carried aboard a NASA DC-8 Airborne Science laboratory, it can penetrate clouds and also collect data at night. AirSAR's high-resolution sensors operate at multiple wavelengths, polarizations and in interferometric modes, which allows the radar tool to "see" beneath treetops, through thin sand and dry snow pack. The sensors, in turn, produce topographic models.

photo: research

This tree trunk is typical of those found in the La Selva region of the Costa Rican rain forest.
NASA Photo / Jim Ross

The highly modified aircraft bearing AirSAR departed Dryden March 1, bound first for southern Mexico and Central America.

"Central America's unique environment and irreplaceable archaeology are being altered and destroyed at an alarming rate," said Dr. Ghassem Asrar, NASA Associate Administrator for Earth Science.   "Natural and cultural resources may disappear unless accurately inventoried. NASA's AirSAR campaign provides unique data not available from other spaceborne or commercial observational platforms that will help scientists characterize past and present human impacts on the landscape. "

photo: research

The DC-8 flying laboratory takes off from Juan Santamaria International Airport in San Jose, Costa Rica, on NASA's AirSAR 2004 campaign.
NASA Photo / Jim Ross

"Meanwhile, in South America and Antarctica, AirSAR will enable better assessments of how climate change is impacting glaciers and ice shelves and contributing to sea-level rise."

Much of the archaeological evidence needed to understand Pre-Columbian societies in Central America comes from identifying and documenting remaining features on the landscape. Difficult terrain and logistics limit ground-data collection; previous remote-sensing techniques were unable to penetrate the forest canopy. AirSAR is expected to detect features such as fortifications, causeways, walls and other evidence of advanced civilizations hidden beneath the forest. Images will shed insight into how modern humans interact with their landscape, how ancient peoples lived and what became of them.

photo: research

Tom Mace, left, and Walter Klein brief John Danilovich, center, U.S. Ambassador to Costa Rica, and NASA Administrator Sean O'Keefe on board NASA's DC-8.
NASA Photo / Jim Ross

AirSAR's archaeological applications were first demonstrated at Angkor, Cambodia, in 1996. It provided better detail than radar images obtained from a previous Space Shuttle flight.

After leaving Central America, the team will continue on to survey Patagonian ice fields in Chile and then to the Antarctic Peninsula, where AirSAR will collect imagery and high-precision topography data to help determine the contribution of southern-hemisphere glaciers to sea level rise due to climate change. In the Patagonian region, a recent study by NASA and others found that the contribution more than doubled from 1995 to 2000 as compared to the previous 25 years. AirSAR will make it possible to determine whether that trend is continuing at the present pace or accelerating.

photo: research

Jet Propulsion Laboratory researcher Tim Miller, above, sits at the primary AirSAR station on board NASA's DC-8 Flying Laboratory.
NASA Photo / Jim Ross

Little is known about the poorly mapped glaciers in the Antarctic Peninsula, an area 10 times larger than the region of Patagonia, which encompasses territory in Chile and Argentina. The Antarctic region recently experienced rapid atmospheric warming, triggering a widespread retreat of floating ice shelves, reducing permanent snow cover and lengthening the melt season. Information on ice shelf thickness provided by AirSAR will aid in measuring the contribution of glacial melting to sea level rise. The data also will provide a precise topographic reference for comparison with satellite laser-altimetry data from NASA's Icesat satellite and airborne data previously collected.

AirSAR's scientific mission would not be possible without NASA's unique DC-8 flying laboratory, a converted jetliner that has flown hundreds of Earth Science payloads.

"Dryden has provided the international science community with this heavy-lift airborne laboratory and its flight crew, engineering staff, ground and maintenance personnel and support staff, capable of flying virtually anywhere," said Dryden's DC-8 mission manager, Walter Klein.

The 2004 AirSAR campaign is a collaborative effort among U.S. and Central American scientists and institutions, including NASA, the National Science Foundation, the Smithsonian Institute, the National Geographic Society, Conservation International, the Organization of Tropical Studies, the Central American Commission for Environment and Development and the Inter-American Development Bank.

photo: A rain forest lizard. Photo: A Tree Frog
A lizard is documented in his natural rain forest habitat.
NASA Photo / Jim Ross
A tree frog goes about his business in his natural surroundings.
NASA Photo / Jim Ross

For information about AirSAR on the Internet, visit: and /centers/dryden/research/AirSci/index2.html

New photos of NASA's DC-8 flying laboratory can be downloaded at: