This Echo is READ ONLY !   NO Un-Authorized Messages Please!
 ~~~~~~~~~~~~~~~~~~~~~~~~   ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

John Bluck                      July 8, 2003
NASA Ames Research Center, Moffett Field, Calif.
Phone: 650/604-5026 or 604-9000
E-mail:  John.G.Bluck{at}nasa.gov

Ann Marie Menting
Boston University, Boston
Phone: 617/358-1240
E-mail: amenting{at}bu.edu

Release: 03-51AR     
NASA DATA MINING REVEALS A NEW HISTORY OF NATURAL DISASTERS

NASA is using satellite data to paint a detailed global picture of 
the interplay among natural disasters, human activities and the rise 
of carbon dioxide in the Earth's atmosphere during the past 20 years.

According to a new scientific study that appears in the July issue of 
the journal Global Change Biology, scientists used satellite 
observations to estimate the amount of leafy cover worldwide and 
sudden decreases in 'greenness.' Greenness is a measure of the amount 
of chlorophyll in live plants.

"Green leaf cover is probably the most fragile and vulnerable piece 
of Earth's ecosystem that scientists can easily monitor during 
ecological disturbances," said Christopher Potter, a scientist at 
NASA Ames Research Center, located in California's Silicon Valley, 
and the principal author of the technical paper. His co-authors 
include Pang-Ning Tan, Michael Steinbach and Vipin Kumar, all of the 
University of Minnesota, Minneapolis; Steven Klooster and Vanessa 
Genovese, both of California State University-Monterey Bay, Seaside, 
Calif.; and Ranga Myneni, Boston University, Boston.

"The new results come from a technique called 'data mining,' which 
sorts through a huge amount of satellite and scientific data to 
detect patterns and events that otherwise would have been 
overlooked," added Kumar, the principal investigator of a joint 
project of the University of Minnesota, California State University 
and NASA Ames to develop data-mining techniques to help Earth 
scientists discover changes in the global carbon cycle and climate 
system.

The Earth's land cover is so vast that much of it in the tropics and 
the tundra is inaccessible to regular ground observations there, 
according to the study's scientists. "Many years of satellite 
observations of remote areas have revealed completely new pictures of 
ecological changes and disasters, but we have had to develop new 
formulas to clearly reveal sudden changes in greenness over extensive 
areas," said Potter.

Detecting sudden changes from large amounts of global data required 
the development of automated techniques that take into account the 
timing, location and magnitude of such changes, according to Tan.

Researchers then matched abrupt changes in plant greenness with 
records of large wildfires or massive crop losses to validate the 
study's conclusions. "The majority of the potential disturbance 
events that caused carbon to go into the atmosphere occurred in 
tropical savanna and shrub lands or in cold forest ecosystems," 
Klooster said.

Scientists define an ecological disturbance as an event that disrupts 
the physical make-up of an ecosystem and how it works for longer than 
one growing season of native plants. Natural disturbances may include 
fires, hurricanes, floods, droughts, lava flows and ice storms. Other 
natural disturbances are due to plant-eating insects and mammals, and 
disease-causing microorganisms.

Human-caused disturbances could happen as a result of logging, 
deforestation, draining wetlands, clearing, chemical pollution and 
introducing non-native species to an area, according to scientists.

"Ecosystem disturbances can contribute to the current rise of carbon 
dioxide in the atmosphere," Potter said. Nine billion metric tons of 
carbon may have moved from the Earth's soil and surface life forms 
into the atmosphere in 18 years beginning in 1982 due to wildfires 
and other disturbances, according to the study. A metric ton is 2,205 
pounds, equivalent to the weight of a small car. In comparison, 
fossil fuel emission of carbon dioxide to the atmosphere each year 
was about seven billion metric tons in 1990.

Some of the carbon dioxide that goes into the air reenters the 
Earth's biosphere when plants recover this gas during 'natural 
recycling.'

Scientists used the Advanced Very High Resolution Radiometer aboard 
National Oceanic and Atmospheric Administration satellites to measure 
monthly changes in leafy plant cover worldwide. Boston University 
used unique NASA computer codes to produce global greenness values. 
These codes removed interfering data from atmospheric effects. When 
statistics showed there was much less greenness in specific areas 
that lasted more than a year, scientists also found a high 
probability of ecological disturbances.

"Watching for changes in the amount of absorption of sunlight by 
green plants is an effective way to look for ecological disasters," 
Potter said. "This study was literally a proof of concept because we 
learned how to use data mining to bring new knowledge out of existing 
Earth observation data," Klooster added.

Follow-up studies using much higher resolution satellite images are 
likely to reveal more localized events, such as floods, hurricanes 
and major logging operations, according to the study's scientists. 
"This is important because many natural disasters in remote areas are 
not noticed and never recorded," Potter explained.

"In the new era of worldwide carbon accounting and management, we 
need an accurate method to tell us how much carbon dioxide is moving 
from the biosphere and into the atmosphere," Potter said. "Global 
satellite images go beyond the capability of human eyesight. All we 
need to do is look at the data with the proper formulas to filter out 
just what we need," he concluded.

Publication size images are on the World Wide Web at:

http://amesnews.arc.nasa.gov/releases/2003/03images/datamine/
datamine.html

-end-

 - END OF FILE -
==========

@Message posted automagically by IMTHINGS POST 1.30
---